Targeting the transient receptor potential vanilloid type 1 (TRPV1) assembly domain attenuates inflammation-induced hypersensitivity.

PubMed

Flynn, Robyn; Chapman, Kevin; Iftinca, Mircea; Aboushousha, Reem; Varela, Diego; Altier, Christophe

2014-06-13

The transient receptor potential channel vanilloid type 1 (TRPV1) is a non-selective cation channel expressed in sensory neurons of the dorsal root and trigeminal ganglia. TRPV1 is a polymodal channel activated by noxious heat, capsaicin, and protons. As a sensor for noxious stimuli, TRPV1 channel has been described as a key contributor to pain signaling. To form a functional channel, TRPV1 subunits must assemble into tetramers, and several studies have identified the TRPV1 C terminus as an essential element in subunit association. Here we combined biochemical assays with electrophysiology and imaging-based bimolecular fluorescence complementation (BiFC) and bioluminescence resonance energy transfer (BRET) in live cells to identify a short motif in the C-terminal tail of the TRPV1 subunit that governs channel assembly. Removing this region through early truncation or targeted deletion results in loss of subunit association and channel function. Importantly, we found that interfering with TRPV1 subunit association using a plasma membrane-tethered peptide attenuated mechanical and thermal hypersensitivity in two mouse models of inflammatory hyperalgesia. This represents a novel mechanism to disrupt TRPV1 subunit assembly and hence may offer a new analgesic tool for pain relief. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

What do we know about the transient receptor potential vanilloid 2 (TRPV2) ion channel?

PubMed

Perálvarez-Marín, Alex; Doñate-Macian, Pau; Gaudet, Rachelle

2013-11-01

Transient receptor potential (TRP) ion channels are emerging as a new set of membrane proteins involved in a vast array of cellular processes and regulated by a large number of physical and chemical stimuli, which involves them with sensory cell physiology. The vanilloid TRP subfamily (TRPV) named after the vanilloid receptor 1 (TRPV1) consists of six members, and at least four of them (TRPV1-TRPV4) have been related to thermal sensation. One of the least characterized members of the TRP subfamily is TRPV2. Although initially characterized as a noxious heat sensor, TRPV2 now seems to have little to do with temperature sensing but a much more complex physiological profile. Here we review the available information and research progress on the structure, physiology and pharmacology of TRPV2 in an attempt to shed some light on the physiological and pharmacological deorphanization of TRPV2. © 2013 FEBS.

What do we know about the Transient Receptor Potential Vanilloid 2 (TRPV2) ion channel?

PubMed Central

Perálvarez-Marín, Alex; Doñate-Macian, Pau; Gaudet, Rachelle

2013-01-01

Transient receptor potential (TRP) ion channels are emerging as a new set of membrane proteins involved in a vast array of cellular processes and regulated by a large number of physical and chemical stimuli, which involves them with sensory cell physiology. The vanilloid TRP subfamily (TRPV) named after the vanilloid receptor 1 (TRPV1) consists of six members, and at least four of them (TRPV1-TRPV4) have been related to thermal sensation. One of the least characterized members of the TRP subfamily is TRPV2. Although initially characterized as a noxious heat sensor, TRPV2 now seems to have little to do with temperature sensing, but a much more complex physiological profile. Here we review the available information and research progress on the structure, physiology and pharmacology of TRPV2 in an attempt to shed some light on the physiological and pharmacological deorphanization of TRPV2. PMID:23615321

Adrenergic receptors inhibit TRPV1 activity in the dorsal root ganglion neurons of rats.

PubMed

Matsushita, Yumi; Manabe, Miki; Kitamura, Naoki; Shibuya, Izumi

2018-01-01

Transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor channel that responds to multiple types of stimuli, such as heat, acid, mechanical pressure and some vanilloids. Capsaicin is the most commonly used vanilloid to stimulate TRPV1. TRPV1 channels are expressed in dorsal root ganglion neurons that extend to Aδ- and C-fibers and have a role in the transduction of noxious inputs to the skin into the electrical signals of the sensory nerve. Although noradrenergic nervous systems, including the descending antinociceptive system and the sympathetic nervous system, are known to modulate pain sensation, the functional association between TRPV1 and noradrenaline in primary sensory neurons has rarely been examined. In the present study, we examined the effects of noradrenaline on capsaicin-evoked currents in cultured dorsal root ganglion neurons of the rat by the whole-cell voltage clamp method. Noradrenaline at concentrations higher than 0.1 pM significantly reduced the amplitudes of the inward capsaicin currents recorded at -60 mV holding potential. This inhibitory action was reversed by either yohimbine (an α2 antagonist, 10 nM) or propranolol (a β antagonist, 10 nM). The α2 agonists, clonidine (1 pM) and dexmedetomidine (1 pM) inhibited capsaicin currents, and yohimbine (1 nM) reversed the effects of clonidine. The inhibitory action of noradrenaline was not seen in the neurons pretreated with pertussis toxin (100 μg/ml for 24 h) and the neurons dialyzed intracellularly with guanosine 5'- [β-thio] diphosphate (GDPβS, 200 μM), the catalytic subunit of protein kinase A (250 U/ml) or okadaic acid (1 μM). These results suggest that noradrenaline directly acts on dorsal root ganglion neurons to inhibit the activity of TRPV1 depending on the activation of α2-adrenoceptors followed by the inhibition of the adenylate cyclase/cAMP/protein kinase A pathway.

Identification of a tetramerization domain in the C terminus of the vanilloid receptor.

PubMed

García-Sanz, Nuria; Fernández-Carvajal, Asia; Morenilla-Palao, Cruz; Planells-Cases, Rosa; Fajardo-Sánchez, Emmanuel; Fernández-Ballester, Gregorio; Ferrer-Montiel, Antonio

2004-06-09

TRPV1 (transient receptor potential vanilloid receptor subtype 1) is a member of the TRP channel family gated by vanilloids, protons, and heat. Structurally, TRPV1 appears to be a tetramer formed by the assembly of four identical subunits around a central aqueous pore. The molecular determinants that govern its subunit oligomerization remain elusive. Here, we report the identification of a segment comprising 684Glu-721Arg (referred to as the TRP-like domain) in the C terminus of TRPV1 as an association domain (AD) of the protein. Purified recombinant C terminus of TRPV1 (TRPV1-C) formed discrete and stable multimers in vitro. Yeast two-hybrid and pull-down assays showed that self-association of the TRPV1-C is blocked when segment 684Glu-721Arg is deleted. Biochemical and immunological analysis indicate that removal of the AD from full-length TRPV1 monomers blocks the formation of stable heteromeric assemblies with wild-type TRPV1 subunits. Deletion of the AD in a poreless TRPV1 subunit suppressed its robust dominant-negative phenotype. Together, these findings are consistent with the tenet that the TRP-like domain in TRPV1 is a molecular determinant of the tetramerization of receptor subunits into functional channels. Our observations suggest that the homologous TRP domain in the TRP protein family may function as a general, evolutionary conserved AD involved in subunit multimerization.

Nociceptor Response - A Review of Literature

DTIC Science & Technology

2015-02-20

receptor potential vanilloid, type 4 (TRPV4) receptors respond to temperatures above 27 °C; TRPV3, TRPV1 , and TRPV2 respond to temperature increases...respond to temperatures above 27 °C; TRPV3, TRPV1 , and TRPV2 respond to temperature increases above 31 °C, 43 °C, and 52 °C, respectively (Kandel et al...2013). TRPV1 channels are intrinsically heat sensitive and negatively regulated by phosphoinositide lipids. Neuron, 77(4), 667-679. 15

Possible involvement of the transient receptor potential vanilloid type 1 channel in postoperative adhesive obstruction and its prevention by a kampo (traditional Japanese) medicine, daikenchuto.

PubMed

Tokita, Yohei; Yamamoto, Masahiro; Satoh, Kazuko; Nishiyama, Mitsue; Iizuka, Seiichi; Imamura, Sachiko; Kase, Yoshio

2011-01-01

This study focused on the localization of transient receptor potential vanilloid type 1 (TRPV1) in the intestines in postoperative adhesion model rats and investigated the underlying mechanism for the anti-adhesion action of daikenchuto (DKT), especially in relation to TRPV1. Postoperative intestinal adhesion was induced by sprinkling talc in the small intestine. The expression of TRPV1 mRNA was examined by in situ hybridization and real-time RT-PCR. The effects of DKT and its major ingredient, hydroxy sanshool, with or without ruthenium red, a TRP-channel antagonist, on talc-induced intestinal adhesions were evaluated. The level of TRPV1 mRNA was higher in the adhesion regions of talc-treated rats than in normal small intestine of sham-operated rats. Localization of TRPV1 mRNA expression was identified in the submucosal plexus of both sham-operated and talc-treated rats; and in talc-treated rats, it was observed also in the myenteric plexus and regions of adhesion. Capsaicin, DKT, and hydroxy sanshool significantly prevented formation of intestinal adhesions. The effects of DKT and hydroxy sanshool were abrogated by subcutaneous injection of ruthenium red. These results suggest that pharmacological modulation of TRPV1 might be a possible therapeutic option in postoperative intestinal adhesion, which might be relevant to the prevention of postoperative adhesive obstruction by DKT.

N-arachidonoyl l-serine, an endocannabinoid-like brain constituent with vasodilatory properties

PubMed Central

Milman, Garry; Maor, Yehoshua; Abu-Lafi, Saleh; Horowitz, Michal; Gallily, Ruth; Batkai, Sandor; Mo, Fong-Ming; Offertaler, Laszlo; Pacher, Pal; Kunos, George; Mechoulam, Raphael

2006-01-01

The endocannabinoid N-arachidonoyl ethanolamine (anandamide), found both in the CNS and in the periphery, plays a role in numerous physiological systems. One might expect that the chemically related N-arachidonoyl-l-serine (ARA-S) could also be formed alongside anandamide. We have now isolated ARA-S from bovine brain and elucidated its structure by comparison with synthetic ARA-S. Contrary to anandamide, ARA-S binds very weakly to cannabinoid CB1 and CB2 or vanilloid TRPV1 (transient receptor potential vanilloid 1) receptors. However, it produces endothelium-dependent vasodilation of rat isolated mesenteric arteries and abdominal aorta and stimulates phosphorylation of p44/42 mitogen-activated protein (MAP) kinase and protein kinase B/Akt in cultured endothelial cells. ARA-S also suppresses LPS-induced formation of TNF-α in a murine macrophage cell line and in wild-type mice, as well as in mice deficient in CB1 or CB2 receptors. Many of these effects parallel those reported for abnormal cannabidiol (Abn-CBD), a synthetic agonist of a putative novel cannabinoid-type receptor. Hence, ARA-S may represent an endogenous agonist for this receptor. PMID:16467152

Structural insights into transient receptor potential vanilloid type 1 (TRPV1) from homology modeling, flexible docking, and mutational studies.

PubMed

Lee, Jin Hee; Lee, Yoonji; Ryu, HyungChul; Kang, Dong Wook; Lee, Jeewoo; Lazar, Jozsef; Pearce, Larry V; Pavlyukovets, Vladimir A; Blumberg, Peter M; Choi, Sun

2011-04-01

The transient receptor potential vanilloid subtype 1 (TRPV1) is a non-selective cation channel composed of four monomers with six transmembrane helices (TM1-TM6). TRPV1 is found in the central and peripheral nervous system, and it is an important therapeutic target for pain relief. We describe here the construction of a tetrameric homology model of rat TRPV1 (rTRPV1). We experimentally evaluated by mutational analysis the contribution of residues of rTRPV1 contributing to ligand binding by the prototypical TRPV1 agonists, capsaicin and resiniferatoxin (RTX). We then performed docking analysis using our homology model. The docking results with capsaicin and RTX showed that our homology model was reliable, affording good agreement with our mutation data. Additionally, the binding mode of a simplified RTX (sRTX) ligand as predicted by the modeling agreed well with those of capsaicin and RTX, accounting for the high binding affinity of the sRTX ligand for TRPV1. Through the homology modeling, docking and mutational studies, we obtained important insights into the ligand-receptor interactions at the molecular level which should prove of value in the design of novel TRPV1 ligands.

Involvement of Transient Receptor Potential Vanilloid (TRPV) 4 in mouse sperm thermotaxis.

PubMed

Hamano, Koh-Ichi; Kawanishi, Tae; Mizuno, Atsuko; Suzuki, Makoto; Takagi, Yuji

2016-08-25

Transient Receptor Potential Vanilloid (TRPV) 4 is one of the temperature-sensitive ion channels involved in temperature receptors, and it is known to be activated from 35 to 40ºC. Here we analyzed sperm motility function of Trpv4 knockout (KO) mouse in temperature-gradient conditions to elucidate the thermotaxis of mouse sperm and the involvement of TRPV4 in thermotaxis. The sperm were introduced at the vertical column end of a T-shaped chamber filled with medium in a plastic dish, and we measured the number of sperm that arrived at both ends of the wide column where we had established a temperature gradient of approx. 2ºC, and we evaluated the sperm's thermotaxis. Large numbers of wild-type (WT) mouse sperm migrated into the high level of the temperature gradient that was set in the wide column, and thermotaxis was confirmed. The ratio of migrated sperm at the high temperature level of the T-shaped chamber was decreased in the KO sperm and Ruthenium red (a TRPV antagonist) treated sperm compared with the WT sperm. The thermotaxis of the mouse sperm was confirmed, and the involvement of TRPV4 in this thermotaxis was suggested.

Structural insights into transient receptor potential vanilloid type 1 (TRPV1) from homology modeling, flexible docking, and mutational studies

NASA Astrophysics Data System (ADS)

Lee, Jin Hee; Lee, Yoonji; Ryu, HyungChul; Kang, Dong Wook; Lee, Jeewoo; Lazar, Jozsef; Pearce, Larry V.; Pavlyukovets, Vladimir A.; Blumberg, Peter M.; Choi, Sun

2011-04-01

The transient receptor potential vanilloid subtype 1 (TRPV1) is a non-selective cation channel composed of four monomers with six transmembrane helices (TM1-TM6). TRPV1 is found in the central and peripheral nervous system, and it is an important therapeutic target for pain relief. We describe here the construction of a tetrameric homology model of rat TRPV1 (rTRPV1). We experimentally evaluated by mutational analysis the contribution of residues of rTRPV1 contributing to ligand binding by the prototypical TRPV1 agonists, capsaicin and resiniferatoxin (RTX). We then performed docking analysis using our homology model. The docking results with capsaicin and RTX showed that our homology model was reliable, affording good agreement with our mutation data. Additionally, the binding mode of a simplified RTX (sRTX) ligand as predicted by the modeling agreed well with those of capsaicin and RTX, accounting for the high binding affinity of the sRTX ligand for TRPV1. Through the homology modeling, docking and mutational studies, we obtained important insights into the ligand-receptor interactions at the molecular level which should prove of value in the design of novel TRPV1 ligands.

Acetaminophen Metabolite N-Acylphenolamine Induces Analgesia via Transient Receptor Potential Vanilloid 1 Receptors Expressed on the Primary Afferent Terminals of C-fibers in the Spinal Dorsal Horn.

PubMed

Ohashi, Nobuko; Uta, Daisuke; Sasaki, Mika; Ohashi, Masayuki; Kamiya, Yoshinori; Kohno, Tatsuro

2017-08-01

The widely used analgesic acetaminophen is metabolized to N-acylphenolamine, which induces analgesia by acting directly on transient receptor potential vanilloid 1 or cannabinoid 1 receptors in the brain. Although these receptors are also abundant in the spinal cord, no previous studies have reported analgesic effects of acetaminophen or N-acylphenolamine mediated by the spinal cord dorsal horn. We hypothesized that clinical doses of acetaminophen induce analgesia via these spinal mechanisms. We assessed our hypothesis in a rat model using behavioral measures. We also used in vivo and in vitro whole cell patch-clamp recordings of dorsal horn neurons to assess excitatory synaptic transmission. Intravenous acetaminophen decreased peripheral pinch-induced excitatory responses in the dorsal horn (53.1 ± 20.7% of control; n = 10; P < 0.01), while direct application of acetaminophen to the dorsal horn did not reduce these responses. Direct application of N-acylphenolamine decreased the amplitudes of monosynaptic excitatory postsynaptic currents evoked by C-fiber stimulation (control, 462.5 ± 197.5 pA; N-acylphenolamine, 272.5 ± 134.5 pA; n = 10; P = 0.022) but not those evoked by stimulation of Aδ-fibers. These phenomena were mediated by transient receptor potential vanilloid 1 receptors, but not cannabinoid 1 receptors. The analgesic effects of acetaminophen and N-acylphenolamine were stronger in rats experiencing an inflammatory pain model compared to naïve rats. Our results suggest that the acetaminophen metabolite N-acylphenolamine induces analgesia directly via transient receptor potential vanilloid 1 receptors expressed on central terminals of C-fibers in the spinal dorsal horn and leads to conduction block, shunt currents, and desensitization of these fibers.

Photothermal and mechanical stimulation of cells via dualfunctional nanohybrids

NASA Astrophysics Data System (ADS)

Chechetka, Svetlana A.; Doi, Motomichi; Pichon, Benoit P.; Bégin-Colin, Sylvie; Miyako, Eijiro

2016-11-01

Stimulating cells by light is an attractive technology to investigate cellular function and deliver innovative cell-based therapy. However, current techniques generally use poorly biopermeable light, which prevents broad applicability. Here, we show that a new type of composite nanomaterial, synthesized from multi-walled carbon nanotubes, magnetic iron nanoparticles, and polyglycerol, enables photothermal and mechanical control of Ca2+ influx into cells overexpressing transient receptor potential vanilloid type-2. The nanohybrid is simply operated by application of highly biotransparent near-infrared light and a magnetic field. The technology may revolutionize remote control of cellular function.

Transient receptor potential vanilloid type 2 (TRPV2) expression in normal urothelium and in urothelial carcinoma of human bladder: correlation with the pathologic stage.

PubMed

Caprodossi, Sara; Lucciarini, Roberta; Amantini, Consuelo; Nabissi, Massimo; Canesin, Giacomo; Ballarini, Patrizia; Di Spilimbergo, Adriana; Cardarelli, Marco Andrea; Servi, Lucilla; Mammana, Gabriele; Santoni, Giorgio

2008-09-01

To evaluate the expression of transient receptor potential vanilloid type 2 (TRPV2) in normal human bladder and urothelial carcinoma (UC) tissues. Bladder specimens were obtained by transurethral resection or radical cystectomy. TRPV2 mRNA expression in normal human urothelial cells (NHUCs), UC cell lines, and formalin-fixed paraffin-embedded normal (n=6) and cancer bladder tissues (n=58) was evaluated by polymerase chain reaction (PCR) and quantitative real-time PCR (RT-PCR). TRPV2 protein expression was assessed by cytofluorimetric and confocal microscopy analyses in NHUCs and UC cells and by Western blotting and immunohistochemistry in normal and UC tissues. Enhanced TRPV2 mRNA and protein expression was found in high-grade and -stage UC specimens and UC cell lines. Both the full-length TRPV2 (hTRPV2) and a short splice-variant (s-TRPV2) were detected in NHUC and normal bladder specimens, whereas a progressive decline of s-TRPV2 in pTa, pT1, and pT2 stages was observed, up to a complete loss in pT3 and pT4 UC specimens. Normal human urothelial cells and bladder tissue specimens express TRPV2 at both the mRNA and protein levels. A progressive loss of s-TRPV2 accompanied by a marked increase of hTRPV2 expression was found in high-grade and -stage UC tissues.

A shifted repertoire of endocannabinoid genes in the zebrafish (Danio rerio).

PubMed

McPartland, J M; Glass, Michelle; Matias, Isabel; Norris, Ryan W; Kilpatrick, C William

2007-05-01

The zebrafish has served as a model organism for developmental biology. Sequencing its genome has expanded zebrafish research into physiology and drug-development testing. Several cannabinoid pharmaceuticals are in development, but expression of endocannabinoid receptors and enzymes remains unknown in this species. We conducted a bioinformatics analysis of the zebrafish genome using 17 human endocannabinoid genes as a reference set. Putative zebrafish orthologs were identified in filtered BLAST searches as reciprocal best hits. Orthology was confirmed by three in silico methods: phylogenetic testing, synteny analysis, and functional mapping. Zebrafish expressed orthologs of cannabinoid receptor 1, transient receptor potential channel vanilloid receptor 4, GPR55 receptor, fatty acid amide hydrolase 1, monoacylglycerol lipase, NAPE-selective phospholipase D, abhydrolase domain-containing protein 4, and diacylglycerol lipase alpha and beta; and paired paralogs of cannabinoid receptor 2, fatty acid amide hydrolase 2, peroxisome proliferator-activated receptor alpha, prostaglandin-endoperoxide synthase 2, and transient receptor potential cation channel subtype A1. Functional mapping suggested the orthologs of transient receptor potential vanilloid receptor 1 and peroxisome proliferator-activated receptor gamma lack specific amino acids critical for cannabinoid ligand binding. No orthologs of N-acylethanolamine acid amidase or protein tyrosine phosphatase, non-receptor type 22 were identified. In conclusion, the zebrafish genome expresses a shifted repertoire of endocannabinoid genes. In vitro analyses are warranted before using zebrafish for cannabinoid development testing.

The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature.

PubMed

Alawi, Khadija M; Aubdool, Aisah A; Liang, Lihuan; Wilde, Elena; Vepa, Abhinav; Psefteli, Maria-Paraskevi; Brain, Susan D; Keeble, Julie E

2015-10-01

Transient receptor potential vanilloid 1 (TRPV1) is involved in sensory nerve nociceptive signaling. Recently, it has been discovered that TRPV1 receptors also regulate basal body temperature in multiple species from mice to humans. In the present study, we investigated whether TRPV1 modulates basal sympathetic nervous system (SNS) activity. C57BL6/J wild-type (WT) mice and TRPV1 knockout (KO) mice were implanted with radiotelemetry probes for measurement of core body temperature. AMG9810 (50 mg/kg) or vehicle (2% DMSO/5% Tween 80/10 ml/kg saline) was injected intraperitoneally. Adrenoceptor antagonists or vehicle (5 ml/kg saline) was injected subcutaneously. In WT mice, the TRPV1 antagonist, AMG9810, caused significant hyperthermia, associated with increased noradrenaline concentrations in brown adipose tissue. The hyperthermia was significantly attenuated by the β-adrenoceptor antagonist propranolol, the mixed α-/β-adrenoceptor antagonist labetalol, and the α1-adrenoceptor antagonist prazosin. TRPV1 KO mice have a normal basal body temperature, indicative of developmental compensation. d-Amphetamine (potent sympathomimetic) caused hyperthermia in WT mice, which was reduced in TRPV1 KO mice, suggesting a decreased sympathetic drive in KOs. This study provides new evidence that TRPV1 controls thermoregulation upstream of the SNS, providing a potential therapeutic target for sympathetic hyperactivity thermoregulatory disorders. © FASEB.

Drug-induced mild therapeutic hypothermia obtained by administration of a transient receptor potential vanilloid type 1 agonist.

PubMed

Fosgerau, Keld; Weber, Uno J; Gotfredsen, Jacob W; Jayatissa, Magdalena; Buus, Carsten; Kristensen, Niels B; Vestergaard, Mogens; Teschendorf, Peter; Schneider, Andreas; Hansen, Philip; Raunsø, Jakob; Køber, Lars; Torp-Pedersen, Christian; Videbaek, Charlotte

2010-10-09

The use of mechanical/physical devices for applying mild therapeutic hypothermia is the only proven neuroprotective treatment for survivors of out of hospital cardiac arrest. However, this type of therapy is cumbersome and associated with several side-effects. We investigated the feasibility of using a transient receptor potential vanilloid type 1 (TRPV1) agonist for obtaining drug-induced sustainable mild hypothermia. First, we screened a heterogeneous group of TRPV1 agonists and secondly we tested the hypothermic properties of a selected candidate by dose-response studies. Finally we tested the hypothermic properties in a large animal. The screening was in conscious rats, the dose-response experiments in conscious rats and in cynomologus monkeys, and the finally we tested the hypothermic properties in conscious young cattle (calves with a body weight as an adult human). The investigated TRPV1 agonists were administered by continuous intravenous infusion. Screening: Dihydrocapsaicin (DHC), a component of chili pepper, displayed a desirable hypothermic profile with regards to the duration, depth and control in conscious rats. Dose-response experiments: In both rats and cynomologus monkeys DHC caused a dose-dependent and immediate decrease in body temperature. Thus in rats, infusion of DHC at doses of 0.125, 0.25, 0.50, and 0.75 mg/kg/h caused a maximal ΔT (°C) as compared to vehicle control of -0.9, -1.5, -2.0, and -4.2 within approximately 1 hour until the 6 hour infusion was stopped. Finally, in calves the intravenous infusion of DHC was able to maintain mild hypothermia with ΔT > -3°C for more than 12 hours. Our data support the hypothesis that infusion of dihydrocapsaicin is a candidate for testing as a primary or adjunct method of inducing and maintaining therapeutic hypothermia.

The vanilloid receptor TRPV1 is tonically activated in vivo and involved in body temperature regulation.

PubMed

Gavva, Narender R; Bannon, Anthony W; Surapaneni, Sekhar; Hovland, David N; Lehto, Sonya G; Gore, Anu; Juan, Todd; Deng, Hong; Han, Bora; Klionsky, Lana; Kuang, Rongzhen; Le, April; Tamir, Rami; Wang, Jue; Youngblood, Brad; Zhu, Dawn; Norman, Mark H; Magal, Ella; Treanor, James J S; Louis, Jean-Claude

2007-03-28

The vanilloid receptor TRPV1 (transient receptor potential vanilloid 1) is a cation channel that serves as a polymodal detector of pain-producing stimuli such as capsaicin, protons (pH <5.7), and heat. TRPV1 antagonists block pain behaviors in rodent models of inflammatory, neuropathic, and cancer pain, suggesting their utility as analgesics. Here, we report that TRPV1 antagonists representing various chemotypes cause an increase in body temperature (hyperthermia), identifying a potential issue for their clinical development. Peripheral restriction of antagonists did not eliminate hyperthermia, suggesting that the site of action is predominantly outside of the blood-brain barrier. Antagonists that are ineffective against proton activation also caused hyperthermia, indicating that blocking capsaicin and heat activation of TRPV1 is sufficient to produce hyperthermia. All TRPV1 antagonists evaluated here caused hyperthermia, suggesting that TRPV1 is tonically activated in vivo and that TRPV1 antagonism and hyperthermia are not separable. TRPV1 antagonists caused hyperthermia in multiple species (rats, dogs, and monkeys), demonstrating that TRPV1 function in thermoregulation is conserved from rodents to primates. Together, these results indicate that tonic TRPV1 activation regulates body temperature.

TRPV2.

PubMed

Kojima, Itaru; Nagasawa, Masahiro

2014-01-01

Transient receptor potential vanilloid type 2, TRPV2, is a calcium-permeable cation channel belonging to the TRPV channel family. This channel is activated by heat (>52 °C), various ligands, and mechanical stresses. In most of the cells, a large portion of TRPV2 is located in the endoplasmic reticulum under unstimulated conditions. Upon stimulation of the cells with phosphatidylinositol 3-kinase-activating ligands, TRPV2 is translocated to the plasma membrane and functions as a cation channel. Mechanical stress may also induce translocation of TRPV2 to the plasma membrane. The expression of TRPV2 is high in some types of cells including neurons, neuroendocrine cells, immune cells involved in innate immunity, and certain types of cancer cells. TRPV2 may modulate various cellular functions in these cells.

Capsaicin: Friend or Foe in Skin Cancer and Other Related Malignancies?

PubMed

Georgescu, Simona-Roxana; Sârbu, Maria-Isabela; Matei, Clara; Ilie, Mihaela Adriana; Caruntu, Constantin; Constantin, Carolina; Neagu, Monica; Tampa, Mircea

2017-12-16

Capsaicin is the main pungent in chili peppers, one of the most commonly used spices in the world; its analgesic and anti-inflammatory properties have been proven in various cultures for centuries. It is a lipophilic substance belonging to the class of vanilloids and an agonist of the transient receptor potential vanilloid 1 receptor. Taking into consideration the complex neuro-immune impact of capsaicin and the potential link between inflammation and carcinogenesis, the effect of capsaicin on muco-cutaneous cancer has aroused a growing interest. The aim of this review is to look over the most recent data regarding the connection between capsaicin and muco-cutaneous cancers, with emphasis on melanoma and muco-cutaneous squamous cell carcinoma.

Caged vanilloid ligands for activation of TRPV1 receptors by 1- and 2-photon excitation†

PubMed Central

Zhao, Jun; Gover, Tony D.; Muralidharan, Sukumaran; Auston, Darryl A.; Weinreich, Daniel; Kao, Joseph P. Y.

2008-01-01

Nociceptive neurons in the peripheral nervous system detect noxious stimuli and report the information to the central nervous system. Most nociceptive neurons express the vanilloid receptor, TRPV1, a non-selective cation channel gated by vanilloid ligands such as capsaicin, the pungent essence of chili peppers. Here, we report the synthesis and biological application of two caged vanilloids—biologically inert precursors that, when photolyzed, release bioactive vanilloid ligands. The two caged vanilloids, Nb-VNA and Nv-VNA, are photoreleased with quantum efficiency of 0.13 and 0.041, respectively. Under flash photolysis conditions, photorelease of Nb-VNA and Nv-VNA is 95% complete in ∼40 μs and ∼125 μs, respectively. Through 1-photon excitation with ultraviolet light (360 nm), or 2-photon excitation with red light (720 nm), the caged vanilloids can be photoreleased in situ to activate TRPV1 receptors on nociceptive neurons. The consequent increase in intracellular free Ca2+ concentration ([Ca2+]i) can be visualized by laser-scanning confocal imaging of neurons loaded with the fluorescent Ca2+ indicator, fluo-3. Stimulation results from TRPV1 receptor activation, because the response is blocked by capsazepine, a selective TRPV1 antagonist. In Ca2+-free extracellular medium, photoreleased vanilloid can still elevate [Ca2+]i, which suggests that TRPV1 receptors also reside on endomembranes in neurons and can mediate Ca2+ release from intracellular stores. Notably, whole-cell voltage clamp measurements showed that flash photorelease of vanilloid can activate TRPV1 channels in < 4 msec at 22°C. In combination with 1- or 2-photon excitation, caged vanilloids are a powerful tool for probing morphologically distinct structures of nociceptive sensory neurons with high spatial and temporal precision. PMID:16605259

Functional transient receptor potential vanilloid 1 and transient receptor potential vanilloid 4 channels along different segments of the renal vasculature.

PubMed

Chen, L; Kaßmann, M; Sendeski, M; Tsvetkov, D; Marko, L; Michalick, L; Riehle, M; Liedtke, W B; Kuebler, W M; Harteneck, C; Tepel, M; Patzak, A; Gollasch, M

2015-02-01

Transient receptor potential vanilloid 1 (TRPV1) and vanilloid 4 (TRPV4) cation channels have been recently identified to promote endothelium-dependent relaxation of mouse mesenteric arteries. However, the role of TRPV1 and TRPV4 in the renal vasculature is largely unknown. We hypothesized that TRPV1/4 plays a role in endothelium-dependent vasodilation of renal blood vessels. We studied the distribution of functional TRPV1/4 along different segments of the renal vasculature. Mesenteric arteries were studied as control vessels. The TRPV1 agonist capsaicin relaxed mouse mesenteric arteries with an EC50 of 25 nm, but large mouse renal arteries or rat descending vasa recta only at >100-fold higher concentrations. The vasodilatory effect of capsaicin in the low-nanomolar concentration range was endothelium-dependent and absent in vessels of Trpv1 -/- mice. The TRPV4 agonist GSK1016790A relaxed large conducting renal arteries, mesenteric arteries and vasa recta with EC50 of 18, 63 nm and ~10 nm respectively. These effects were endothelium-dependent and inhibited by a TRPV4 antagonist, AB159908 (10 μm). Capsaicin and GSK1016790A produced vascular dilation in isolated mouse perfused kidneys with EC50 of 23 and 3 nm respectively. The capsaicin effects were largely reduced in Trpv1 -/- kidneys, and the effects of GSK1016790A were inhibited in Trpv4 -/- kidneys. Our results demonstrate that two TRPV channels have unique sites of vasoregulatory function in the kidney with functional TRPV1 having a narrow, discrete distribution in the resistance vasculature and TRPV4 having more universal, widespread distribution along different vascular segments. We suggest that TRPV1/4 channels are potent therapeutic targets for site-specific vasodilation in the kidney. © 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

[6]-shogaol induces Ca²⁺ signals by activating the TRPV1 channels in the rat insulinoma INS-1E cells.

PubMed

Rebellato, Paola; Islam, Md Shahidul

2014-01-10

[6]-shogaol is a vanilloid compound present in steamed ginger (Zingiber officinale), a commonly used spice. Pancreatic beta-cells respond to nutrients like glucose, amino acids and fatty acids, by an increase in the cytoplasmic free Ca²⁺ concentration ([Ca²⁺](i)), which mediates diverse cellular processes in these cells. Some vanilloid compounds activate the transient receptor potential vanilloid receptor type 1 (TRPV1) channel. We investigated whether [6]-shogaol could trigger Ca²⁺ signals in the beta-cell. [Ca²⁺](i) was measured from single INS-1E cells by microscope-based fluorometry using fura-2 as the Ca²⁺ indicator. In fura-2 loaded single rat insulinoma INS-1E cells, a widely used model of beta-cell, [6]-shogaol increased [Ca²⁺](i) in a concentration-dependent manner. [Ca²⁺](i) increase by [6]-shogaol was completely blocked when Ca²⁺ was omitted from the extracellular medium. Capsazepine, an inhibitor of the TRPV1 ion channel completely inhibited the [6]-shogaol-induced [Ca²⁺](i) increase. [Ca²⁺](i) increase obtained by 1 µM [6]-shogaol was greater than that obtained by 10 mM glucose. Moreover, a sub-stimulatory concentration of [6]-shogaol (300 nM), significantly enhanced the glucose-induced [Ca²⁺](i) increase in these cells. We conclude that [6]-shogaol induces Ca²⁺ signals in the beta-cell by activating the TRPV1 channels, and it sensitizes the beta-cells to stimulation by glucose.

Functionally important amino acid residues in the transient receptor potential vanilloid 1 (TRPV1) ion channel – an overview of the current mutational data

PubMed Central

2013-01-01

This review aims to create an overview of the currently available results of site-directed mutagenesis studies on transient receptor potential vanilloid type 1 (TRPV1) receptor. Systematization of the vast number of data on the functionally important amino acid mutations of TRPV1 may provide a clearer picture of this field, and may promote a better understanding of the relationship between the structure and function of TRPV1. The review summarizes information on 112 unique mutated sites along the TRPV1, exchanged to multiple different residues in many cases. These mutations influence the effect or binding of different agonists, antagonists, and channel blockers, alter the responsiveness to heat, acid, and voltage dependence, affect the channel pore characteristics, and influence the regulation of the receptor function by phosphorylation, glycosylation, calmodulin, PIP2, ATP, and lipid binding. The main goal of this paper is to publish the above mentioned data in a form that facilitates in silico molecular modelling of the receptor by promoting easier establishment of boundary conditions. The better understanding of the structure-function relationship of TRPV1 may promote discovery of new, promising, more effective and safe drugs for treatment of neurogenic inflammation and pain-related diseases and may offer new opportunities for therapeutic interventions. PMID:23800232

The endocannabinoid/endovanilloid N-arachidonoyl dopamine (NADA) and synthetic cannabinoid WIN55,212-2 abate the inflammatory activation of human endothelial cells.

PubMed

Wilhelmsen, Kevin; Khakpour, Samira; Tran, Alphonso; Sheehan, Kayla; Schumacher, Mark; Xu, Fengyun; Hellman, Judith

2014-05-09

Although cannabinoids, such as Δ(9)-tetrahydrocannabinol, have been studied extensively for their psychoactive effects, it has become apparent that certain cannabinoids possess immunomodulatory activity. Endothelial cells (ECs) are centrally involved in the pathogenesis of organ injury in acute inflammatory disorders, such as sepsis, because they express cytokines and chemokines, which facilitate the trafficking of leukocytes to organs, and they modulate vascular barrier function. In this study, we find that primary human ECs from multiple organs express the cannabinoid receptors CB1R, GPR18, and GPR55, as well as the ion channel transient receptor potential cation channel vanilloid type 1. In contrast to leukocytes, CB2R is only minimally expressed in some EC populations. Furthermore, we show that ECs express all of the known endocannabinoid (eCB) metabolic enzymes. Examining a panel of cannabinoids, we demonstrate that the synthetic cannabinoid WIN55,212-2 and the eCB N-arachidonoyl dopamine (NADA), but neither anandamide nor 2-arachidonoylglycerol, reduce EC inflammatory responses induced by bacterial lipopeptide, LPS, and TNFα. We find that endothelial CB1R/CB2R are necessary for the effects of NADA, but not those of WIN55,212-2. Furthermore, transient receptor potential cation channel vanilloid type 1 appears to counter the anti-inflammatory properties of WIN55,212-2 and NADA, but conversely, in the absence of these cannabinoids, its inhibition exacerbates the inflammatory response in ECs activated with LPS. These data indicate that the eCB system can modulate inflammatory activation of the endothelium and may have important implications for a variety of acute inflammatory disorders that are characterized by EC activation.

Dopamine modulation of transient receptor potential vanilloid type 1 (TRPV1) receptor in dorsal root ganglia neurons.

PubMed

Chakraborty, Saikat; Rebecchi, Mario; Kaczocha, Martin; Puopolo, Michelino

2016-03-15

The transient receptor potential vanilloid type 1 (TRPV1) receptor plays a key role in the modulation of nociceptor excitability. To address whether dopamine can modulate the activity of TRPV1 channels in nociceptive neurons, the effects of dopamine and dopamine receptor agonists were tested on the capsaicin-activated current recorded from acutely dissociated small diameter (<27 μm) dorsal root ganglia (DRG) neurons. Dopamine or SKF 81297 (an agonist at D1/D5 receptors), caused inhibition of both inward and outward currents by ∼60% and ∼48%, respectively. The effect of SKF 81297 was reversed by SCH 23390 (an antagonist at D1/D5 receptors), confirming that it was mediated by activation of D1/D5 dopamine receptors. In contrast, quinpirole (an agonist at D2 receptors) had no significant effect on the capsaicin-activated current. Inhibition of the capsaicin-activated current by SKF 81297 was mediated by G protein coupled receptors (GPCRs), and highly dependent on external calcium. The inhibitory effect of SKF 81297 on the capsaicin-activated current was not affected when the protein kinase A (PKA) activity was blocked with H89, or when the protein kinase C (PKC) activity was blocked with bisindolylmaleimide II (BIM). In contrast, when the calcium-calmodulin-dependent protein kinase II (CaMKII) was blocked with KN-93, the inhibitory effect of SKF 81297 on the capsaicin-activated current was greatly reduced, suggesting that activation of D1/D5 dopamine receptors may be preferentially linked to CaMKII activity. We suggest that modulation of TRPV1 channels by dopamine in nociceptive neurons may represent a way for dopamine to modulate incoming noxious stimuli. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Elevated expression of transient receptor potential vanilloid type 1 in dorsal root ganglia of rats with endometriosis

PubMed Central

Lian, Yu-Ling; Cheng, Ming-Jun; Zhang, Xian-Xia; Wang, Li

2017-01-01

Pain is the most pronounced complaint of women with endometriosis, however the underlying mechanism is still poorly understood. In the present study, the authors evaluate the effect of transient receptor potential vanilloid type 1 (TRPV1) of dorsal root ganglia (DRG) on endometriosis-associated pain. A total of 36 SD rats were randomly divided into a sham group (n=9) and a Model group (n=27), accepted auto-transplanted pieces of fat or uterus to the pelvic cavity. At 4 weeks, the Model group was randomly subdivided into the following groups: ENDO group (no treatment, n=9), BCTC group (Model + BCTC, an antagonist of TRPV1, n=9), Vehicle group (Model + cyclodextrin, the vehicle of BCTC, n=9). Tail-flick test was performed prior to surgery, 1 h prior to and following treatment of BCTC or cyclodextrin. The expression of TRPV1, substance P (SP), calcitonin gene-related peptide (CGRP) in L1-L6 DRG was measured via immunohistochemistry, western blotting and RT-qPCR. The results indicated that the Model group exhibited a significant decrease in tail flick latency compared to pre-surgical baseline, and the expression of TRPV1, SP, CGRP protein and mRNA in L1-L6 DRG significantly increased compared to the sham group. BCTC significantly improved tail flick latency, and downregulated the expression of TRPV1, SP and CGRP protein and mRNA levels in L1-L6 DRG compared to ENDO group. However, there were no significant differences of those in Vehicle group compared with the ENDO group. Taken together, the current study provides evidence that TRPV1 expressed in DRG may serve an important role in endometriosis-associated pain. PMID:28627595

Elevated expression of transient receptor potential vanilloid type 1 in dorsal root ganglia of rats with endometriosis.

PubMed

Lian, Yu-Ling; Cheng, Ming-Jun; Zhang, Xian-Xia; Wang, Li

2017-08-01

Pain is the most pronounced complaint of women with endometriosis, however the underlying mechanism is still poorly understood. In the present study, the authors evaluate the effect of transient receptor potential vanilloid type 1 (TRPV1) of dorsal root ganglia (DRG) on endometriosis-associated pain. A total of 36 SD rats were randomly divided into a sham group (n=9) and a Model group (n=27), accepted auto‑transplanted pieces of fat or uterus to the pelvic cavity. At 4 weeks, the Model group was randomly subdivided into the following groups: ENDO group (no treatment, n=9), BCTC group (Model + BCTC, an antagonist of TRPV1, n=9), Vehicle group (Model + cyclodextrin, the vehicle of BCTC, n=9). Tail‑flick test was performed prior to surgery, 1 h prior to and following treatment of BCTC or cyclodextrin. The expression of TRPV1, substance P (SP), calcitonin gene‑related peptide (CGRP) in L1‑L6 DRG was measured via immunohistochemistry, western blotting and RT‑qPCR. The results indicated that the Model group exhibited a significant decrease in tail flick latency compared to pre‑surgical baseline, and the expression of TRPV1, SP, CGRP protein and mRNA in L1‑L6 DRG significantly increased compared to the sham group. BCTC significantly improved tail flick latency, and downregulated the expression of TRPV1, SP and CGRP protein and mRNA levels in L1‑L6 DRG compared to ENDO group. However, there were no significant differences of those in Vehicle group compared with the ENDO group. Taken together, the current study provides evidence that TRPV1 expressed in DRG may serve an important role in endometriosis-associated pain.

Bladder pain induced by prolonged peripheral alpha 1A adrenoceptor stimulation involves the enhancement of transient receptor potential vanilloid 1 activity and an increase of urothelial adenosine triphosphate release.

PubMed

Matos, R; Cordeiro, J M; Coelho, A; Ferreira, S; Silva, C; Igawa, Y; Cruz, F; Charrua, A

2016-12-01

Pathophysiological mechanisms of chronic visceral pain (CVP) are unknown. This study explores the association between the sympathetic system and bladder nociceptors activity by testing the effect of a prolonged adrenergic stimulation on transient receptor potential vanilloid 1 (TRPV1) activity and on urothelial adenosine triphosphate (ATP) release. Female Wistar rats received saline, phenylephrine (PHE), PHE + silodosin, PHE + naftopidil or PHE + prazosin. TRPV1 knockout and wild-type mice received saline or PHE. Visceral pain behaviour tests were performed before and after treatment. Cystometry was performed, during saline and capsaicin infusion. Fos immunoreactivity was assessed in L6 spinal cord segment. Human urothelial ATP release induced by mechanical and thermal stimulation was evaluated. Subcutaneous, but not intrathecal, PHE administration induced pain, which was reversed by silodosin, a selective alpha 1A adrenoceptor antagonist, but not by naftopidil, a relatively selective antagonist for alpha 1D adrenoceptor. Silodosin also reversed PHE-induced bladder hyperactivity and L6 spinal cord Fos expression. Thus, in subsequent experiments, only silodosin was used. Wild-type, but not TRPV1 knockout, mice exhibited phenylephrine-induced pain. Capsaicin induced a greater increase in voiding contractions in PHE-treated rats than in control animals, and silodosin reversed this effect. When treated with PHE, ATP release from human urothelial cells was enhanced either by mechanical stimulation or by lowering the thermal threshold of urothelial TRPV1, which becomes abnormally responsive at body temperature. This study suggests that the activation of peripheral alpha 1A adrenoceptors induces CVP, probably through its interaction with TRPV1 and ATP release. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

The Endocannabinoid/Endovanilloid N-Arachidonoyl Dopamine (NADA) and Synthetic Cannabinoid WIN55,212-2 Abate the Inflammatory Activation of Human Endothelial Cells*

PubMed Central

Wilhelmsen, Kevin; Khakpour, Samira; Tran, Alphonso; Sheehan, Kayla; Schumacher, Mark; Xu, Fengyun; Hellman, Judith

2014-01-01

Although cannabinoids, such as Δ9-tetrahydrocannabinol, have been studied extensively for their psychoactive effects, it has become apparent that certain cannabinoids possess immunomodulatory activity. Endothelial cells (ECs) are centrally involved in the pathogenesis of organ injury in acute inflammatory disorders, such as sepsis, because they express cytokines and chemokines, which facilitate the trafficking of leukocytes to organs, and they modulate vascular barrier function. In this study, we find that primary human ECs from multiple organs express the cannabinoid receptors CB1R, GPR18, and GPR55, as well as the ion channel transient receptor potential cation channel vanilloid type 1. In contrast to leukocytes, CB2R is only minimally expressed in some EC populations. Furthermore, we show that ECs express all of the known endocannabinoid (eCB) metabolic enzymes. Examining a panel of cannabinoids, we demonstrate that the synthetic cannabinoid WIN55,212-2 and the eCB N-arachidonoyl dopamine (NADA), but neither anandamide nor 2-arachidonoylglycerol, reduce EC inflammatory responses induced by bacterial lipopeptide, LPS, and TNFα. We find that endothelial CB1R/CB2R are necessary for the effects of NADA, but not those of WIN55,212-2. Furthermore, transient receptor potential cation channel vanilloid type 1 appears to counter the anti-inflammatory properties of WIN55,212-2 and NADA, but conversely, in the absence of these cannabinoids, its inhibition exacerbates the inflammatory response in ECs activated with LPS. These data indicate that the eCB system can modulate inflammatory activation of the endothelium and may have important implications for a variety of acute inflammatory disorders that are characterized by EC activation. PMID:24644287

Establishing a Mouse Model of a Pure Small Fiber Neuropathy with the Ultrapotent Agonist of Transient Receptor Potential Vanilloid Type 1.

PubMed

Lee, Yi-Chen; Lu, Shui-Chin; Hsieh, Yu-Lin

2018-02-13

Patients with diabetes mellitus (DM) or those experiencing the neurotoxic effects of chemotherapeutic agents may develop sensation disorders due to degeneration and injury of small-diameter sensory neurons, referred to as small fiber neuropathy. Present animal models of small fiber neuropathy affect both large- and small-diameter sensory fibers and thus create a neuropathology too complex to properly assess the effects of injured small-diameter sensory fibers. Therefore, it is necessary to develop an experimental model of pure small fiber neuropathy to adequately examine these issues. This protocol describes an experimental model of small fiber neuropathy specifically affecting small-diameter sensory nerves with resiniferatoxin (RTX), an ultrapotent agonist of transient receptor potential vanilloid type 1 (TRPV1), through a single dose of intraperitoneal injection, referred to as RTX neuropathy. This RTX neuropathy showed pathological manifestations and behavioral abnormalities that mimic the clinical characteristics of patients with small fiber neuropathy, including intraepidermal nerve fiber (IENF) degeneration, specifically injury in small-diameter neurons, and induction of thermal hypoalgesia and mechanical allodynia. This protocol tested three doses of RTX (200, 50, and 10 µg/kg, respectively) and concluded that a critical dose of RTX (50 µg/kg) is required for the development of typical small fiber neuropathy manifestations, and prepared a modified immunostaining procedure to investigate IENF degeneration and neuronal soma injury. The modified procedure is fast, systematic, and economic. Behavioral evaluation of neuropathic pain is critical to reveal the function of small-diameter sensory nerves. The evaluation of mechanical thresholds in experimental rodents is particularly challenging and this protocol describes a customized metal mesh that is suitable for this type of assessment in rodents. In summary, RTX neuropathy is a new and easily established experimental model to evaluate the molecular significance and intervention underlying neuropathic pain for the development of therapeutic agents.

Targeting Transient Receptor Potential Vanilloid 1 (TRPV1) Channel Softly: The Discovery of Passerini Adducts as a Topical Treatment for Inflammatory Skin Disorders.

PubMed

Serafini, Marta; Griglio, Alessia; Aprile, Silvio; Seiti, Fabio; Travelli, Cristina; Pattarino, Franco; Grosa, Giorgio; Sorba, Giovanni; Genazzani, Armando A; Gonzalez-Rodriguez, Sara; Butron, Laura; Devesa, Isabel; Fernandez-Carvajal, Asia; Pirali, Tracey; Ferrer-Montiel, Antonio

2018-05-24

Despite being an old molecule, capsaicin is still a hot topic in the scientific community, and the development of new capsaicinoids is a promising pharmacological approach in the management of skin disorders related to inflammation and pruritus. Here we report the synthesis and the evaluation of capsaicin soft drugs that undergo deactivation by the hydrolyzing activity of skin esterases. The implanting of an ester group in the lipophilic moiety of capsaicinoids by the Passerini multicomponent reaction affords both agonists and antagonists that retain transient receptor potential vanilloid 1 channel (TRPV1) modulating activity and, at the same time, are susceptible to hydrolysis. The most promising antagonist identified shows in vivo anti-nociceptive activity on pruritus and hyperalgesia without producing hyperthermia, thus validating it as novel treatment for dermatological conditions that implicate TRPV1 channel dysfunction.

Cannabinoid actions at TRPV channels: effects on TRPV3 and TRPV4 and their potential relevance to gastrointestinal inflammation.

PubMed

De Petrocellis, L; Orlando, P; Moriello, A Schiano; Aviello, G; Stott, C; Izzo, A A; Di Marzo, V

2012-02-01

Plant cannabinoids, like Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD), activate/desensitize thermosensitive transient receptor potential (TRP) channels of vanilloid type-1 or -2 (TRPV1 or TRPV2). We investigated whether cannabinoids also activate/desensitize two other 'thermo-TRP's', the TRP channels of vanilloid type-3 or -4 (TRPV3 or TRPV4), and if the TRPV-inactive cannabichromene (CBC) modifies the expression of TRPV1-4 channels in the gastrointestinal tract. TRP activity was assessed by evaluating elevation of [Ca(2+)](i) in rat recombinant TRPV3- and TRPV4-expressing HEK-293 cells. TRP channel mRNA expression was measured by quantitative RT-PCR in the jejunum and ileum of mice treated with vehicle or the pro-inflammatory agent croton oil. (i) CBD and tetrahydrocannabivarin (THCV) stimulated TRPV3-mediated [Ca(2+)](i) with high efficacy (50-70% of the effect of ionomycin) and potency (EC(50∼) 3.7 μm), whereas cannabigerovarin (CBGV) and cannabigerolic acid (CBGA) were significantly more efficacious at desensitizing this channel to the action of carvacrol than at activating it; (ii) cannabidivarin and THCV stimulated TRPV4-mediated [Ca(2+)](i) with moderate-high efficacy (30-60% of the effect of ionomycin) and potency (EC(50) 0.9-6.4 μm), whereas CBGA, CBGV, cannabinol and cannabigerol were significantly more efficacious at desensitizing this channel to the action of 4-α-phorbol 12,13-didecanoate (4α-PDD) than at activating it; (iii) CBC reduced TRPV1β, TRPV3 and TRPV4 mRNA in the jejunum, and TRPV3 and TRPV4 mRNA in the ileum of croton oil-treated mice. Cannabinoids can affect both the activity and the expression of TRPV1-4 channels, with various potential therapeutic applications, including in the gastrointestinal tract. © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.

Engineering vanilloid-sensitivity into the rat TRPV2 channel

PubMed Central

Zhang, Feng; Hanson, Sonya M; Jara-Oseguera, Andres; Krepkiy, Dmitriy; Bae, Chanhyung; Pearce, Larry V; Blumberg, Peter M; Newstead, Simon; Swartz, Kenton J

2016-01-01

The TRPV1 channel is a detector of noxious stimuli, including heat, acidosis, vanilloid compounds and lipids. The gating mechanisms of the related TRPV2 channel are poorly understood because selective high affinity ligands are not available, and the threshold for heat activation is extremely high (>50°C). Cryo-EM structures of TRPV1 and TRPV2 reveal that they adopt similar structures, and identify a putative vanilloid binding pocket near the internal side of TRPV1. Here we use biochemical and electrophysiological approaches to investigate the resiniferatoxin(RTx) binding site in TRPV1 and to explore the functional relationships between TRPV1 and TRPV2. Collectively, our results support the interaction of vanilloids with the proposed RTx binding pocket, and demonstrate an allosteric influence of a tarantula toxin on vanilloid binding. Moreover, we show that sensitivity to RTx can be engineered into TRPV2, demonstrating that the gating and permeation properties of this channel are similar to TRPV1. DOI: http://dx.doi.org/10.7554/eLife.16409.001 PMID:27177419

Engineering vanilloid-sensitivity into the rat TRPV2 channel.

PubMed

Zhang, Feng; Hanson, Sonya M; Jara-Oseguera, Andres; Krepkiy, Dmitriy; Bae, Chanhyung; Pearce, Larry V; Blumberg, Peter M; Newstead, Simon; Swartz, Kenton J

2016-05-13

The TRPV1 channel is a detector of noxious stimuli, including heat, acidosis, vanilloid compounds and lipids. The gating mechanisms of the related TRPV2 channel are poorly understood because selective high affinity ligands are not available, and the threshold for heat activation is extremely high (>50°C). Cryo-EM structures of TRPV1 and TRPV2 reveal that they adopt similar structures, and identify a putative vanilloid binding pocket near the internal side of TRPV1. Here we use biochemical and electrophysiological approaches to investigate the resiniferatoxin(RTx) binding site in TRPV1 and to explore the functional relationships between TRPV1 and TRPV2. Collectively, our results support the interaction of vanilloids with the proposed RTx binding pocket, and demonstrate an allosteric influence of a tarantula toxin on vanilloid binding. Moreover, we show that sensitivity to RTx can be engineered into TRPV2, demonstrating that the gating and permeation properties of this channel are similar to TRPV1.

CO-LOCALIZATION OF THE VANILLOID CAPSAICIN RECEPTOR AND SUBSTANCE P IN SENSORY NERVE FIBERS INNERVATING COCHLEAR AND VERTEBRO-BASILAR ARTERIES

PubMed Central

VASS, Z.; DAI, C. F.; STEYGER, P. S.; JANCSÓ, G.; TRUNE, D. R.; NUTTALL, A. L.

2014-01-01

Evidence suggests that capsaicin-sensitive substance P (SP)-containing trigeminal ganglion neurons innervate the spiral modiolar artery (SMA), radiating arterioles, and the stria vascularis of the cochlea. Antidromic electrical or chemical stimulation of trigeminal sensory nerves results in neurogenic plasma extravasation in inner ear tissues. The primary aim of this study was to reveal the possible morphological basis of cochlear vascular changes mediated by capsaicin-sensitive sensory nerves. Therefore, the distribution of SP and capsaicin receptor (transient receptor potential vanilloid type 1—TRPV1) was investigated by double immunolabeling to demonstrate the anatomical relationships between the cochlear and vertebro-basilar blood vessels and the trigeminal sensory fiber system. Extensive TRPV1 and SP expression and co-localization were observed in axons within the adventitial layer of the basilar artery, the anterior inferior cerebellar artery, the SMA, and the radiating arterioles of the cochlea. There appears to be a functional relationship between the trigeminal ganglion and the cochlear blood vessels since electrical stimulation of the trigeminal ganglion induced significant plasma extravasation from the SMA and the radiating arterioles. The findings suggest that stimulation of paravascular afferent nerves may result in permeability changes in the basilar and cochlear vascular bed and may contribute to the mechanisms of vertebro-basilar type of headache through the release of SP and stimulation of TPVR1, respectively. We propose that vertigo, tinnitus, and hearing deficits associated with migraine may arise from perturbations of capsaicin-sensitive trigeminal sensory ganglion neurons projecting to the cochlea. PMID:15026132

Pore helix domain is critical to camphor sensitivity of transient receptor potential vanilloid 1 channel.

PubMed

Marsakova, Lenka; Touska, Filip; Krusek, Jan; Vlachova, Viktorie

2012-04-01

The recent discovery that camphor activates and strongly desensitizes the capsaicin-sensitive and noxious heat-sensitive channel transient receptor potential vanilloid subfamily member 1 (TRPV1) has provided new insights and opened up new research paths toward understanding why this naturally occurring monoterpene is widely used in human medicine for its local counter-irritant, antipruritic, and anesthetic properties. However, the molecular basis for camphor sensitivity remains mostly unknown. The authors attempt to explore the nature of the activation pathways evoked by camphor and narrow down a putative interaction site at TRPV1. The authors transiently expressed wild-type or specifically mutated recombinant TRPV1 channels in human embryonic kidney cells HEK293T and recorded cation currents with the whole cell, patch clamp technique. To monitor changes in the spatial distribution of phosphatidylinositol 4,5-bisphosphate, they used fluorescence resonance energy transfer measurements from cells transfected with the fluorescent protein-tagged pleckstrin homology domains of phospholipase C. The results revealed that camphor modulates TRPV1 channel through the outer pore helix domain by affecting its overall gating equilibrium. In addition, camphor, which generally is known to decrease the fluidity of cell plasma membranes, may also regulate the activity of TRPV1 by inducing changes in the spatial distribution of phosphatidylinositol-4,5-bisphosphate on the inner leaflet of the plasma membrane. The findings of this study provide novel insights into the structural basis for the modulation of TRPV1 channel by camphor and may provide an explanation for the mechanism by which camphor modulates thermal sensation in vivo.

Moxibustion relieves visceral hyperalgesia via inhibition of transient receptor potential vanilloid 1 (TRPV1) and heat shock protein (HSP) 70 expression in rat bone marrow cells.

PubMed

Zou, Weiying; Lin, Hua; Liu, Wenwen; Yang, Bei; Wu, Lei; Duan, Limin; Ling, Ping; Zhu, Lingyan; Dai, Qun; Zhao, Lintong; Zou, Ting; Zhang, Dalei

2016-04-01

To investigate the effects of moxibustion on visceral hyperalgesia (VH) and bone marrow cell transient receptor potential vanilloid type 1 (TRPV1) and heat shock protein (HSP) 70 expression in a rat model of VH. Mechanical colorectal distension was performed to induce VH in neonatal Sprague-Dawley rats. Eight-week-old VH rats were treated with moxibustion at acupuncture point BL25 or an ipsilateral non-acupuncture point. Abdominal withdrawal reflex (AWR) scoring and pain threshold pressure assessment were performed before and after moxibustion treatment for 7 consecutive days. The expression of TRPV1 and HSP70 in bone marrow cells was quantified by real-time quantitative PCR. The expression of TRPV1 and HSP70 in bone marrow cells was increased in rats with VH. Moxibustion at BL25 significantly decreased AWR scores and increased pain threshold pressure in rats with VH. Furthermore, moxibustion at BL25 significantly inhibited the VH-induced increase in the expression of TRPV1 and HSP70 in bone marrow cells. The up-regulation of TRPV1 and HSP70 expression in bone marrow cells may be involved in visceral pain development and the analgesic effect of moxibustion on VH may be mediated through down-regulation of TRPV1 and HSP70 expression in bone marrow cells. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Characterization of Transient Receptor Potential Vanilloid-1 (TRPV1) Variant Activation by Coal Fly Ash Particles and Associations with Altered Transient Receptor Potential Ankyrin-1 (TRPA1) Expression and Asthma*

PubMed Central

Stockmann, Chris; Romero, Erin G.; Lu, Zhenyu; Shapiro, Darien; Stone, Bryan L.; Fassl, Bernhard; Nkoy, Flory; Uchida, Derek A.; Ward, Robert M.; Veranth, John M.; Reilly, Christopher A.

2016-01-01

Transient receptor potential (TRP) channels are activated by environmental particulate materials. We hypothesized that polymorphic variants of transient receptor potential vanilloid-1 (TRPV1) would be uniquely responsive to insoluble coal fly ash compared with the prototypical soluble agonist capsaicin. Furthermore, these changes would manifest as differences in lung cell responses to these agonists and perhaps correlate with changes in asthma symptom control. The TRPV1-I315M and -T469I variants were more responsive to capsaicin and coal fly ash. The I585V variant was less responsive to coal fly ash particles due to reduced translation of protein and an apparent role for Ile-585 in activation by particles. In HEK-293 cells, I585V had an inhibitory effect on wild-type TRPV1 expression, activation, and internalization/agonist-induced desensitization. In normal human bronchial epithelial cells, IL-8 secretion in response to coal fly ash treatment was reduced for cells heterozygous for TRPV1-I585V. Finally, both the I315M and I585V variants were associated with worse asthma symptom control with the effects of I315M manifesting in mild asthma and those of the I585V variant manifesting in severe, steroid-insensitive individuals. This effect may be due in part to increased transient receptor potential ankyrin-1 (TRPA1) expression by lung epithelial cells expressing the TRPV1-I585V variant. These findings suggest that specific molecular interactions control TRPV1 activation by particles, differential activation, and desensitization of TRPV1 by particles and/or other agonists, and cellular changes in the expression of TRPA1 as a result of I585V expression could contribute to variations in asthma symptom control. PMID:27758864

Characterization of Transient Receptor Potential Vanilloid-1 (TRPV1) Variant Activation by Coal Fly Ash Particles and Associations with Altered Transient Receptor Potential Ankyrin-1 (TRPA1) Expression and Asthma.

PubMed

Deering-Rice, Cassandra E; Stockmann, Chris; Romero, Erin G; Lu, Zhenyu; Shapiro, Darien; Stone, Bryan L; Fassl, Bernhard; Nkoy, Flory; Uchida, Derek A; Ward, Robert M; Veranth, John M; Reilly, Christopher A

2016-11-25

Transient receptor potential (TRP) channels are activated by environmental particulate materials. We hypothesized that polymorphic variants of transient receptor potential vanilloid-1 (TRPV1) would be uniquely responsive to insoluble coal fly ash compared with the prototypical soluble agonist capsaicin. Furthermore, these changes would manifest as differences in lung cell responses to these agonists and perhaps correlate with changes in asthma symptom control. The TRPV1-I315M and -T469I variants were more responsive to capsaicin and coal fly ash. The I585V variant was less responsive to coal fly ash particles due to reduced translation of protein and an apparent role for Ile-585 in activation by particles. In HEK-293 cells, I585V had an inhibitory effect on wild-type TRPV1 expression, activation, and internalization/agonist-induced desensitization. In normal human bronchial epithelial cells, IL-8 secretion in response to coal fly ash treatment was reduced for cells heterozygous for TRPV1-I585V. Finally, both the I315M and I585V variants were associated with worse asthma symptom control with the effects of I315M manifesting in mild asthma and those of the I585V variant manifesting in severe, steroid-insensitive individuals. This effect may be due in part to increased transient receptor potential ankyrin-1 (TRPA1) expression by lung epithelial cells expressing the TRPV1-I585V variant. These findings suggest that specific molecular interactions control TRPV1 activation by particles, differential activation, and desensitization of TRPV1 by particles and/or other agonists, and cellular changes in the expression of TRPA1 as a result of I585V expression could contribute to variations in asthma symptom control. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Potential therapeutic value of TRPV1 and TRPA1 in diabetes mellitus and obesity.

PubMed

Derbenev, Andrei V; Zsombok, Andrea

2016-05-01

Diabetes mellitus and obesity, which is a major risk factor in the development of type 2 diabetes mellitus, have reached epidemic proportions worldwide including the USA. The current statistics and forecasts, both short- and long-term, are alarming and predict severe problems in the near future. Therefore, there is a race for developing new compounds, discovering new receptors, or finding alternative solutions to prevent and/or treat the symptoms and complications related to obesity and diabetes mellitus. It is well demonstrated that members of the transient receptor potential (TRP) superfamily play a crucial role in a variety of biological functions both in health and disease. In the recent years, transient receptor potential vanilloid type 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1) were shown to have beneficial effects on whole body metabolism including glucose homeostasis. TRPV1 and TRPA1 have been associated with control of weight, pancreatic function, hormone secretion, thermogenesis, and neuronal function, which suggest a potential therapeutic value of these channels. This review summarizes recent findings regarding TRPV1 and TRPA1 in association with whole body metabolism with emphasis on obese and diabetic conditions.

The potentiating effect of calcitonin gene-related peptide on transient receptor potential vanilloid-1 activity and the electrophysiological responses of rat trigeminal neurons to nociceptive stimuli.

PubMed

Chatchaisak, Duangthip; Connor, Mark; Srikiatkhachorn, Anan; Chetsawang, Banthit

2018-05-01

Growing evidence suggests that calcitonin gene-related peptide (CGRP) participates in trigeminal nociceptive responses. However, the role of CGRP in sensitization or desensitization of nociceptive transduction remains poorly understood. In this study, we sought to further investigate the CGRP-induced up-regulation of transient receptor potential vanilloid-1 (TRPV1) and the responses of trigeminal neurons to nociceptive stimuli. Rat trigeminal ganglion (TG) organ cultures and isolated trigeminal neurons were incubated with CGRP. An increase in TRPV1 levels was observed in CGRP-incubated TG organ cultures. CGRP potentiated capsaicin-induced increase in phosphorylated CaMKII levels in the TG organ cultures. The incubation of the trigeminal neurons with CGRP significantly increased the inward currents in response to capsaicin challenge, and this effect was inhibited by co-incubation with the CGRP receptor antagonist, BIBN4068BS or the inhibitor of protein kinase A, H-89. These findings reveal that CGRP acting on trigeminal neurons may play a significant role in facilitating cellular events that contribute to the peripheral sensitization of the TG in nociceptive transmission.

Transient Receptor Potential Vanilloid 4 Activation-Induced Increase in Glycine-Activated Current in Mouse Hippocampal Pyramidal Neurons.

PubMed

Qi, Mengwen; Wu, Chunfeng; Wang, Zhouqing; Zhou, Li; Men, Chen; Du, Yimei; Huang, Songming; Chen, Lei; Chen, Ling

2018-01-01

Glycine plays an important role in regulating hippocampal inhibitory/ excitatory neurotransmission through activating glycine receptors (GlyRs) and acting as a co-agonist of N-methyl-d-aspartate-type glutamate receptors. Activation of transient receptor potential vanilloid 4 (TRPV4) is reported to inhibit hippocampal A-type γ-aminobutyric acid receptor, a ligand-gated chloride ion channel. GlyRs are also ligand-gated chloride ion channels and this paper aimed to explore whether activation of TRPV4 could modulate GlyRs. Whole-cell patch clamp recording was employed to record glycine-activated current (IGly) and Western blot was conducted to assess GlyRs subunits protein expression. Application of TRPV4 agonist (GSK1016790A or 5,6-EET) increased IGly in mouse hippocampal CA1 pyramidal neurons. This action was blocked by specific antagonists of TRPV4 (RN-1734 or HC-067047) and GlyR (strychnine), indicating that activation of TRPV4 increases strychnine-sensitive GlyR function in mouse hippocampal pyramidal neurons. GSK1016790A-induced increase in IGly was significantly attenuated by protein kinase C (PKC) (BIM II or D-sphingosine) or calcium/calmodulin-dependent protein kinase II (CaMKII) (KN-62 or KN-93) antagonists but was unaffected by protein kinase A or protein tyrosine kinase antagonists. Finally, hippocampal protein levels of GlyR α1 α2, α3 and β subunits were not changed by treatment with GSK1016790A for 30 min or 1 h, but GlyR α2, α3 and β subunits protein levels increased in mice that were intracerebroventricularly (icv.) injected with GSK1016790A for 5 d. Activation of TRPV4 increases GlyR function and expression, and PKC and CaMKII signaling pathways are involved in TRPV4 activation-induced increase in IGly. This study indicates that GlyRs may be effective targets for TRPV4-induced modulation of hippocampal inhibitory neurotransmission. © 2018 The Author(s). Published by S. Karger AG, Basel.

A possible participation of transient receptor potential vanilloid type 1 channels in the antidepressant effect of fluoxetine.

PubMed

Manna, Shyamshree S S; Umathe, Sudhir N

2012-06-15

The present study investigated the influence of transient receptor vanilloid type 1 (TRPV1) channel agonist (capsaicin) and antagonist (capsazepine) either alone or in combination with traditional antidepressant drug, fluoxetine; or a serotonin hydroxylase inhibitor, para-chlorophenylalanine; or a glutamate N-methyl-D-aspartate (NMDA) receptor agonist, NMDA on the forced swim test and tail suspension test using male Swiss mice. Results revealed that intracerebroventricular injections of capsaicin (200 and 300 μg/mouse) and capsazepine (100 and 200 μg/mouse) reduced the immobility time, exhibiting antidepressant-like activity that was comparable to the effects of fluoxetine (2.5-10 μg/mouse) in both the tests. However, in the presence of inactive dose (10 μg/mouse) of capsazepine, capsaicin (300 μg/mouse) had no influence on the indices of both tests, signifying that the effects are TRPV1-mediated. Further, the antidepressant-like effects of both the TRPV1 ligands were neutralized in mice-pretreated with NMDA (0.1 μg/mouse), suggestive of the fact that decreased glutamatergic transmission might contribute to the antidepressant-like activity. In addition, co-administration of sub-threshold dose of capsazepine (10 μg/mouse) and fluoxetine (1.75 μg/mouse) produced a synergistic effect in both the tests. In contrast, inactive doses of capsaicin (10 and 100 μg/mouse) partially abolished the antidepressant effect of fluoxetine (10 μg/mouse), while its effect was potentiated by active dose of capsaicin (200 μg/mouse). Moreover, pretreatment of mice with para-chlorophenylalanine (300 mg/kg/day × 3 days, i.p.) attenuated the effects of capsaicin and capsazepine, demonstrating a probable interplay between serotonin and TRPV1, at least in parts. Thus, our data indicate a possible role of TRPV1 in depressive-like symptoms. Copyright © 2012 Elsevier B.V. All rights reserved.

Efficacy of ABT-116, an antagonist of transient receptor potential vanilloid type 1, in providing analgesia for dogs with chemically induced synovitis.

PubMed

Cathcart, Curtis J; Johnston, Spencer A; Reynolds, Lisa R; Al-Nadaf, Sami; Budsberg, Steven C

2012-01-01

To investigate the ability of ABT-116 (a proprietary antagonist of transient receptor potential vanilloid type 1) administered at 2 doses to attenuate lameness in dogs with experimentally induced urate synovitis. 8 purpose-bred mixed-breed dogs. In a 4-way crossover study, dogs orally received each of low-dose ABT-116 treatment (LDA; 10 mg/kg), high-dose ABT-116 treatment (HDA; 30 mg/kg), firocoxib (5 mg/kg), and no treatment (nontreatment) once a day for 2 days, in a randomly assigned order. Synovitis was induced on the second day of each treatment period by intra-articular injection of either stifle joint with sodium urate, alternating between joints for each treatment period, beginning with the left stifle joint. Ground reaction forces, clinical lameness scores, and rectal temperature were assessed before the injection (baseline) and at various points afterward. Lameness scores at the 2-, 6-, and 12-hour assessment points were higher than baseline scores for HDA and nontreatment, whereas scores at the 2- and 6-hour points were higher than baseline scores for LDA. For firocoxib, there was no difference from baseline scores in lameness scores at any point. Compared with baseline values, peak vertical force and vertical impulse were lower at 2 and 6 hours for HDA and nontreatment and at 2 hours for LDA. No changes in these values were evident for firocoxib. The HDA or LDA resulted in higher rectal temperatures than did treatment with firocoxib or nothing, but those temperatures did not differ among treatments. HDA had no apparent effect on sodium urate-induced lameness; LDA did attenuate the lameness but not as completely as firocoxib treatment. High rectal temperature is an adverse effect of oral ABT-116 administration that may be of clinical concern.

The stress protein heat shock cognate 70 (Hsc70) inhibits the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel.

PubMed

Iftinca, Mircea; Flynn, Robyn; Basso, Lilian; Melo, Helvira; Aboushousha, Reem; Taylor, Lauren; Altier, Christophe

2016-01-01

Specialized cellular defense mechanisms prevent damage from chemical, biological, and physical hazards. The heat shock proteins have been recognized as key chaperones that maintain cell survival against a variety of exogenous and endogenous stress signals including noxious temperature. However, the role of heat shock proteins in nociception remains poorly understood. We carried out an expression analysis of the constitutively expressed 70 kDa heat-shock cognate protein, a member of the stress-induced HSP70 family in lumbar dorsal root ganglia from a mouse model of Complete Freund's Adjuvant-induced chronic inflammatory pain. We used immunolabeling of dorsal root ganglion neurons, behavioral analysis and patch clamp electrophysiology in both dorsal root ganglion neurons and HEK cells transfected with Hsc70 and Transient Receptor Potential Channels to examine their functional interaction in heat shock stress condition. We report an increase in protein levels of Hsc70 in mouse dorsal root ganglia, 3 days post Complete Freund's Adjuvant injection in the hind paw. Immunostaining of Hsc70 was observed in most of the dorsal root ganglion neurons, including the small size nociceptors immunoreactive to the TRPV1 channel. Standard whole-cell patch-clamp technique was used to record Transient Receptor Potential Vanilloid type 1 current after exposure to heat shock. We found that capsaicin-evoked currents are inhibited by heat shock in dorsal root ganglion neurons and transfected HEK cells expressing Hsc70 and TRPV1. Blocking Hsc70 with matrine or spergualin compounds prevented heat shock-induced inhibition of the channel. We also found that, in contrast to TRPV1, both the cold sensor channels TRPA1 and TRPM8 were unresponsive to heat shock stress. Finally, we show that inhibition of TRPV1 depends on the ATPase activity of Hsc70 and involves the rho-associated protein kinase. Our work identified Hsc70 and its ATPase activity as a central cofactor of TRPV1 channel function and points to the role of this stress protein in pain associated with neurodegenerative and/or metabolic disorders, including aging. © The Author(s) 2016.

7-tert-Butyl-6-(4-chloro-phenyl)-2-thioxo-2,3-dihydro-1H-pyrido[2,3-d]pyrimidin-4-one, a classic polymodal inhibitor of transient receptor potential vanilloid type 1 with a reduced liability for hyperthermia, is analgesic and ameliorates visceral hypersensitivity.

PubMed

Nash, Mark S; McIntyre, Peter; Groarke, Alex; Lilley, Elliot; Culshaw, Andrew; Hallett, Allan; Panesar, Moh; Fox, Alyson; Bevan, Stuart

2012-08-01

The therapeutic potential of transient receptor potential vanilloid type 1 (TRPV1) antagonists for chronic pain has been recognized for more than a decade. However, preclinical and clinical data revealed that acute pharmacological blockade of TRPV1 perturbs thermoregulation, resulting in hyperthermia, which is a major hurdle for the clinical development of these drugs. Here, we describe the properties of 7-tert-butyl-6-(4-chloro-phenyl)-2-thioxo-2,3-dihydro-1H-pyrido[2,3-d]pyrimidin-4-one (BCTP), a TRPV1 antagonist with excellent analgesic properties that does not induce significant hyperthermia in rodents at doses providing maximal analgesia. BCTP is a classic polymodal inhibitor of TRPV1, blocking activation of the human channel by capsaicin and low pH with IC(50) values of 65.4 and 26.4 nM, respectively. Similar activity was observed with rat TRPV1, and the inhibition by BCTP was competitive and reversible. BCTP also blocked heat-induced activation of TRPV1. In rats, the inhibition of capsaicin-induced mechanical hyperalgesia was observed with a D(50) value of 2 mg/kg p.o. BCTP also reversed visceral hypersensitivity and somatic inflammatory pain, and using a model of neuropathic pain in TRPV1 null mice we confirmed that its analgesic properties were solely through the inhibition of TRPV1. We were surprised to find that BCTP administered orally induced only a maximal 0.6°C increase in core body temperature at the highest tested doses (30 and 100 mg/kg), contrasting markedly with N-[4-({6-[4-(trifluoromethyl)phenyl]pyrimidin-4-yl}oxy)-1,3-benzothiazol-2-yl]acetamide (AMG517), a clinically tested TRPV1 antagonist, which induced marked hyperthermia (>1°C) at doses eliciting submaximal reversal of capsaicin-induced hyperalgesia. The combined data indicate that TRPV1 antagonists with a classic polymodal inhibition profile can be identified where the analgesic action is separated from the effects on body temperature.

Diversity effect of capsaicin on different types of skeletal muscle.

PubMed

Zhou, Gan; Wang, Lina; Xu, Yaqiong; Yang, Kelin; Luo, Lv; Wang, Leshan; Li, Yongxiang; Wang, Jiawen; Shu, Gang; Wang, Songbo; Gao, Ping; Zhu, Xiaotong; Xi, Qianyun; Sun, Jiajie; Zhang, Yongliang; Jiang, Qingyan

2018-06-01

Capsaicin is a major pungent content in green and red peppers which are widely used as spice, and capsaicin may activate different receptors. To determine whether capsaicin has different effects on different types of skeletal muscle, we applied different concentrations (0, 0.01, and 0.02%) of capsaicin in the normal diet and conducted a four-week experiment on Sprague-Dawley rats. The fiber type composition, glucose metabolism enzyme activity, and different signaling molecules' expressions of receptors were detected. Our results suggested that capsaicin reduced the body fat deposition, while promoting the slow muscle-related gene expression and increasing the enzyme activity in the gastrocnemius and soleus muscles. However, fatty acid metabolism was significantly increased only in the soleus muscle. The study of intracellular signaling suggested that the transient receptor potential vanilloid 1 (TRPV1) and cannabinoid receptors in the soleus muscle were more sensitive to capsaicin. In conclusion, the distribution of TRPV1 and cannabinoid receptors differs in different types of muscle, and the different roles of capsaicin in different types of muscle may be related to the different degrees of activation of receptors.

Trypsin induces biphasic muscle contraction and relaxation via transient receptor potential vanilloid 1 and neurokinin receptors 1/2 in porcine esophageal body.

PubMed

Xiaopeng, Bai; Tanaka, Yoshimasa; Ihara, Eikichi; Hirano, Katsuya; Nakano, Kayoko; Hirano, Mayumi; Oda, Yoshinao; Nakamura, Kazuhiko

2017-02-15

Duodenal reflux of fluids containing trypsin relates to refractory gastroesophageal reflux disease (GERD). Esophageal peristalsis and clearance are important factors in GERD pathogenesis. However, the function of trypsin in esophageal body contractility is not fully understood. In this study, effects of trypsin on circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) of the porcine esophageal body were examined. Trypsin elicited a concentration dependent biphasic response, a major contraction and a subsequent relaxation only in CSM. In CSM, contraction occurred at trypsin concentrations of 100nM and relaxation at 1μM. A proteinase-activated receptor (PAR)2 activating peptide, SLIGKV-NH 2 (1mM), induced a monophasic contraction. Those responses were unaffected by tetrodotoxin though abolished by the gap junction uncouplers carbenoxolone and octanol. They were also partially inhibited by a transient receptor potential vanilloid type 1 (TRPV1) antagonist and abolished by combination of neurokinin receptor 1 (NK 1 ) and NK 2 antagonists, but not by an NK 3 antagonist, suggesting a PAR2-TRPV1-substance P pathway in sensory neurons. Substance P (100nM), an agonist for various NK receptors (NK 1 , NK 2 and NK 3 ) with differing affinities, induced significant contraction in CSM, but not in LSM. The contraction was also blocked by the combination of NK 1 and NK 2 antagonists, but not by the NK 3 antagonist. Moreover, substance P-induced contractions were unaffected by the TRPV1 antagonist, but inhibited by a gap junction uncoupler. In conclusion, trypsin induced a biphasic response only in CSM and this was mediated by PAR2, TRPV1 and NK 1/2 . Gap junctions were indispensable in this tachykinin-induced response. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrophysiological characteristics of IB4-negative TRPV1-expressing muscle afferent DRG neurons.

PubMed

Lin, Yi-Wen; Chen, Chih-Cheng

2015-01-01

Muscle afferent neurons that express transient receptor potential vanilloid type I (TRPV1) are responsible for muscle pain associated with tissue acidosis. We have previously found that TRPV1 of isolectin B4 (IB4)-negative muscle nociceptors plays an important role in the acid-induced hyperalgesic priming and the development of chronic hyperalgesia in a mouse model of fibromyalgia. To understand the electrophysiological properties of the TRPV1-expressing muscle afferent neurons, we used whole-cell patch clamp recording to study the acid responsiveness and action potential (AP) configuration of capsaicin-sensitive neurons innervating to gastrocnemius muscle. Here we showed that IB4-negative TRPV1-expressing muscle afferent neurons are heterogeneous in terms of cell size, resting membrane potential, AP configuration, tetrodotoxin (TTX)-resistance, and acid-induced current (I acid), as well as capsaicin-induced current (I cap). TRPV1-expressing neurons were all acid-sensitive and could be divided into two acid-sensitive groups depending on an acid-induced sustained current (type I) or an acid-induced biphasic ASIC3-like current (type II). Type I TRPV1-expressing neurons were distinguishable from type II TRPV1-expressing neurons in AP overshoot, after-hyperpolarization duration, and all I acid parameters, but not in AP threshold, TTX-resistance, resting membrane potential, and I cap parameters. These differential biophysical properties of TRPV1-expressing neurons might partially annotate their different roles involved in the development and maintenance of chronic muscle pain.

Type III Nrg1 back signaling enhances functional TRPV1 along sensory axons contributing to basal and inflammatory thermal pain sensation.

PubMed

Canetta, Sarah E; Luca, Edlira; Pertot, Elyse; Role, Lorna W; Talmage, David A

2011-01-01

Type III Nrg1, a member of the Nrg1 family of signaling proteins, is expressed in sensory neurons, where it can signal in a bi-directional manner via interactions with the ErbB family of receptor tyrosine kinases (ErbB RTKs). Type III Nrg1 signaling as a receptor (Type III Nrg1 back signaling) can acutely activate phosphatidylinositol-3-kinase (PtdIns3K) signaling, as well as regulate levels of α7* nicotinic acetylcholine receptors, along sensory axons. Transient receptor potential vanilloid 1 (TRPV1) is a cation-permeable ion channel found in primary sensory neurons that is necessary for the detection of thermal pain and for the development of thermal hypersensitivity to pain under inflammatory conditions. Cell surface expression of TRPV1 can be enhanced by activation of PtdIns3K, making it a potential target for regulation by Type III Nrg1. We now show that Type III Nrg1 signaling in sensory neurons affects functional axonal TRPV1 in a PtdIns3K-dependent manner. Furthermore, mice heterozygous for Type III Nrg1 have specific deficits in their ability to respond to noxious thermal stimuli and to develop capsaicin-induced thermal hypersensitivity to pain. Cumulatively, these results implicate Type III Nrg1 as a novel regulator of TRPV1 and a molecular mediator of nociceptive function.

Deletion of vanilloid receptor (TRPV1) in mice alters behavioral effects of ethanol

PubMed Central

Blednov, Y.A.; Harris, R.A.

2009-01-01

The vanilloid receptor TRPV1 is activated by ethanol and this may be important for some of the central and peripheral actions of ethanol. To determine if this receptor has a role in ethanol-mediated behaviors, we studied null mutant mice in which the Trpv1 gene was deleted. Mice lacking this gene showed significantly higher preference for ethanol and consumed more ethanol in a two-bottle choice test as compared with wild type littermates. Null mutant mice showed shorter duration of loss of righting reflex induced by low doses of ethanol (3.2 and 3.4 g/kg) and faster recovery from motor incoordination induced by ethanol (2 g/kg). However, there were no differences between null mutant and wild type mice in severity of ethanol-induced acute withdrawal (4 g/kg) or conditioned taste aversion to ethanol (2.5 g/kg). Two behavioral phenotypes (decreased sensitivity to ethanol-induced sedation and faster recovery from ethanol-induced motor incoordination) seen in null mutant mice were reproduced in wild type mice by injection of a TRPV1 antagonist, capsazepine (10 mg/kg). These two ethanol behaviors were changed in the opposite direction after injection of capsaicin, a selective TRPV1 agonist, in wild type mice. The studies provide the first evidence that TRPV1 is important for specific behavioral actions of ethanol. PMID:19705551

Activation of transient receptor potential vanilloid-1 (TRPV1) influences how retinal ganglion cell neurons respond to pressure-related stress

PubMed Central

Sappington, Rebecca M; Sidorova, Tatiana; Ward, Nicholas J; Chakravarthy, Rohini; Ho, Karen W; Calkins, David J

2015-01-01

Our recent studies implicate the transient receptor potential vanilloid-1 (TRPV1) channel as a mediator of retinal ganglion cell (RGC) function and survival. With elevated pressure in the eye, TRPV1 increases in RGCs, supporting enhanced excitability, while Trpv1 -/- accelerates RGC degeneration in mice. Here we find TRPV1 localized in monkey and human RGCs, similar to rodents. Expression increases in RGCs exposed to acute changes in pressure. In retinal explants, contrary to our animal studies, both Trpv1 -/- and pharmacological antagonism of the channel prevented pressure-induced RGC apoptosis, as did chelation of extracellular Ca2+. Finally, while TRPV1 and TRPV4 co-localize in some RGC bodies and form a protein complex in the retina, expression of their mRNA is inversely related with increasing ocular pressure. We propose that TRPV1 activation by pressure-related insult in the eye initiates changes in expression that contribute to a Ca2+-dependent adaptive response to maintain excitatory signaling in RGCs. PMID:25713995

Peripheral inflammation induces up-regulation of TRPV2 expression in rat DRG.

PubMed

Shimosato, Goshun; Amaya, Fumimasa; Ueda, Masashi; Tanaka, Yoshifumi; Decosterd, Isabelle; Tanaka, Masaki

2005-12-15

The transient receptor potential vanilloid subfamily member 2 (TRPV2) is a cation channel activated by temperatures above 52 degrees C. To analyze the contribution of TRPV2 to the development of inflammation-induced hyperalgesia, the expression of TRPV2 in primary sensory neurons was analyzed after intraplantar injection of complete Freund's adjuvant (CFA). Using specific antibodies, an increase in TRPV2-expressing neurons was identified after inflammation. TRPV2 expression is concentrated in a subset of medium-sized dorsal root ganglion neurons, independent of transient receptor potential vanilloid subfamily member 1 (TRPV1) expression. A similar distribution of TRPV2 was observed after inflammation. Intraplantar injection of nerve growth factor increased TRPV1 expression but not TRPV2, suggesting that induction of TRPV2 expression is driven by a mechanism distinct from that for TRPV1. Heat hyperalgesia assessment after chemical desensitization of TRPV1 by resiniferatoxin demonstrates a possible role for TRPV2 in inflammation at high temperatures (>56 degrees C). These results suggest that TRPV2 upregulation contributes to peripheral sensitization during inflammation and is responsible for pain hypersensitivity to noxious high temperature stimuli.

Mutation of I696 and W697 in the TRP box of vanilloid receptor subtype I modulates allosteric channel activation.

PubMed

Gregorio-Teruel, Lucia; Valente, Pierluigi; González-Ros, José Manuel; Fernández-Ballester, Gregorio; Ferrer-Montiel, Antonio

2014-03-01

The transient receptor potential vanilloid receptor subtype I (TRPV1) channel acts as a polymodal sensory receptor gated by chemical and physical stimuli. Like other TRP channels, TRPV1 contains in its C terminus a short, conserved domain called the TRP box, which is necessary for channel gating. Substitution of two TRP box residues-I696 and W697-with Ala markedly affects TRPV1's response to all activating stimuli, which indicates that these two residues play a crucial role in channel gating. We systematically replaced I696 and W697 with 18 native l-amino acids (excluding cysteine) and evaluated the effect on voltage- and capsaicin-dependent gating. Mutation of I696 decreased channel activation by either voltage or capsaicin; furthermore, gating was only observed with substitution of hydrophobic amino acids. Substitution of W697 with any of the 18 amino acids abolished gating in response to depolarization alone, shifting the threshold to unreachable voltages, but not capsaicin-mediated gating. Moreover, vanilloid-activated responses of W697X mutants showed voltage-dependent gating along with a strong voltage-independent component. Analysis of the data using an allosteric model of activation indicates that mutation of I696 and W697 primarily affects the allosteric coupling constants of the ligand and voltage sensors to the channel pore. Together, our findings substantiate the notion that inter- and/or intrasubunit interactions at the level of the TRP box are critical for efficient coupling of stimulus sensing and gate opening. Perturbation of these interactions markedly reduces the efficacy and potency of the activating stimuli. Furthermore, our results identify these interactions as potential sites for pharmacological intervention.

Inhibition of TRPV1 channels by a naturally occurring omega-9 fatty acid reduces pain and itch

PubMed Central

Morales-Lázaro, Sara L.; Llorente, Itzel; Sierra-Ramírez, Félix; López-Romero, Ana E.; Ortíz-Rentería, Miguel; Serrano-Flores, Barbara; Simon, Sidney A.; Islas, León D.; Rosenbaum, Tamara

2016-01-01

The transient receptor potential vanilloid 1 (TRPV1) ion channel is mainly found in primary nociceptive afferents whose activity has been linked to pathophysiological conditions including pain, itch and inflammation. Consequently, it is important to identify naturally occurring antagonists of this channel. Here we show that a naturally occurring monounsaturated fatty acid, oleic acid, inhibits TRPV1 activity, and also pain and itch responses in mice by interacting with the vanilloid (capsaicin)-binding pocket and promoting the stabilization of a closed state conformation. Moreover, we report an itch-inducing molecule, cyclic phosphatidic acid, that activates TRPV1 and whose pruritic activity, as well as that of histamine, occurs through the activation of this ion channel. These findings provide insights into the molecular basis of oleic acid inhibition of TRPV1 and also into a way of reducing the pathophysiological effects resulting from its activation. PMID:27721373

Structure of the full-length TRPV2 channel by cryo-EM

NASA Astrophysics Data System (ADS)

Huynh, Kevin W.; Cohen, Matthew R.; Jiang, Jiansen; Samanta, Amrita; Lodowski, David T.; Zhou, Z. Hong; Moiseenkova-Bell, Vera Y.

2016-03-01

Transient receptor potential (TRP) proteins form a superfamily Ca2+-permeable cation channels regulated by a range of chemical and physical stimuli. Structural analysis of a `minimal' TRP vanilloid subtype 1 (TRPV1) elucidated a mechanism of channel activation by agonists through changes in its outer pore region. Though homologous to TRPV1, other TRPV channels (TRPV2-6) are insensitive to TRPV1 activators including heat and vanilloids. To further understand the structural basis of TRPV channel function, we determined the structure of full-length TRPV2 at ~5 Å resolution by cryo-electron microscopy. Like TRPV1, TRPV2 contains two constrictions, one each in the pore-forming upper and lower gates. The agonist-free full-length TRPV2 has wider upper and lower gates compared with closed and agonist-activated TRPV1. We propose these newly revealed TRPV2 structural features contribute to diversity of TRPV channels.

Structure of the full-length TRPV2 channel by cryo-EM

PubMed Central

Huynh, Kevin W.; Cohen, Matthew R.; Jiang, Jiansen; Samanta, Amrita; Lodowski, David T.; Zhou, Z. Hong; Moiseenkova-Bell, Vera Y.

2016-01-01

Transient receptor potential (TRP) proteins form a superfamily Ca2+-permeable cation channels regulated by a range of chemical and physical stimuli. Structural analysis of a ‘minimal' TRP vanilloid subtype 1 (TRPV1) elucidated a mechanism of channel activation by agonists through changes in its outer pore region. Though homologous to TRPV1, other TRPV channels (TRPV2–6) are insensitive to TRPV1 activators including heat and vanilloids. To further understand the structural basis of TRPV channel function, we determined the structure of full-length TRPV2 at ∼5 Å resolution by cryo-electron microscopy. Like TRPV1, TRPV2 contains two constrictions, one each in the pore-forming upper and lower gates. The agonist-free full-length TRPV2 has wider upper and lower gates compared with closed and agonist-activated TRPV1. We propose these newly revealed TRPV2 structural features contribute to diversity of TRPV channels. PMID:27021073

Structure of the full-length TRPV2 channel by cryo-EM.

PubMed

Huynh, Kevin W; Cohen, Matthew R; Jiang, Jiansen; Samanta, Amrita; Lodowski, David T; Zhou, Z Hong; Moiseenkova-Bell, Vera Y

2016-03-29

Transient receptor potential (TRP) proteins form a superfamily Ca(2+)-permeable cation channels regulated by a range of chemical and physical stimuli. Structural analysis of a 'minimal' TRP vanilloid subtype 1 (TRPV1) elucidated a mechanism of channel activation by agonists through changes in its outer pore region. Though homologous to TRPV1, other TRPV channels (TRPV2-6) are insensitive to TRPV1 activators including heat and vanilloids. To further understand the structural basis of TRPV channel function, we determined the structure of full-length TRPV2 at ∼5 Å resolution by cryo-electron microscopy. Like TRPV1, TRPV2 contains two constrictions, one each in the pore-forming upper and lower gates. The agonist-free full-length TRPV2 has wider upper and lower gates compared with closed and agonist-activated TRPV1. We propose these newly revealed TRPV2 structural features contribute to diversity of TRPV channels.

αCGRP is essential for algesic exocytotic mobilization of TRPV1 channels in peptidergic nociceptors

PubMed Central

Devesa, Isabel; Ferrándiz-Huertas, Clotilde; Mathivanan, Sakthikumar; Wolf, Christoph; Luján, Rafael; Changeux, Jean-Pierre; Ferrer-Montiel, Antonio

2014-01-01

Proalgesic sensitization of peripheral nociceptors in painful syndromes is a complex molecular process poorly understood that involves mobilization of thermosensory receptors to the neuronal surface. However, whether recruitment of vesicular thermoTRP channels is a general mechanism underlying sensitization of all nociceptor types or is subtype-specific remains controversial. We report that sensitization-induced Ca2+-dependent exocytotic insertion of transient receptor potential vanilloid 1 (TRPV1) receptors to the neuronal plasma membrane is a mechanism specifically used by peptidergic nociceptors to potentiate their excitability. Notably, we found that TRPV1 is present in large dense-core vesicles (LDCVs) that were mobilized to the neuronal surface in response to a sensitizing insult. Deletion or silencing of calcitonin-gene–related peptide alpha (αCGRP) gene expression drastically reduced proalgesic TRPV1 potentiation in peptidergic nociceptors by abrogating its Ca2+-dependent exocytotic recruitment. These findings uncover a context-dependent molecular mechanism of TRPV1 algesic sensitization and a previously unrecognized role of αCGRP in LDCV mobilization in peptidergic nociceptors. Furthermore, these results imply that concurrent secretion of neuropeptides and channels in peptidergic C-type nociceptors facilitates a rapid modulation of pain signaling. PMID:25489075

Design, synthesis, and biological evaluation of novel biphenyl-4-carboxamide derivatives as orally available TRPV1 antagonists.

PubMed

Oka, Hiromasa; Yonezawa, Koichi; Kamikawa, Akio; Ikegai, Kazuhiro; Asai, Norio; Shirakami, Shohei; Miyamoto, Satoshi; Watanabe, Toshihiro; Kiso, Tetsuo; Takemoto, Yukihiro; Tamura, Seiji; Kuramochi, Takahiro

2018-07-23

A new series of transient receptor potential vanilloid type 1 (TRPV1) antagonists were designed and synthesized from N-(3-hydroxyphenyl)-2-(piperidin-1-ylmethyl)biphenyl-4-carboxamide hydrochloride (8). SAR studies identified (R)-N-(1-methyl-2-oxo-1,2,3,4-tetrahydro-7-quinolyl)-2-[(2-methylpyrrolidin-1-yl)methyl]biphenyl-4-carboxamide hydrochloride (ASP8370, 7), as a compound with high aqueous solubility, satisfactory stability in human liver microsomes, and reduced CYP3A4 inhibition. ASP8370 was selected as a clinical development candidate with significant ameliorative effects on neuropathic pain. SAR studies also revealed the structural mechanisms underlying the switching between TRPV1 antagonism and agonism. Copyright © 2018 Elsevier Ltd. All rights reserved.

Piperine: researchers discover new flavor in an ancient spice.

PubMed

Szallasi, Arpad

2005-09-01

Studies with animals that are deficient in the vanilloid (capsaicin) receptor TRPV1 have confirmed the pivotal role that TRPV1 has in the development of post-inflammatory hyperalgesia, and enhanced TRPV1 expression has been described in various human disorders. Natural products have provided several lead structures for the development of vanilloid ligands. A recent study shows that piperine, the irritant principle in black pepper, is more efficient than capsaicin in the desensitization of human TRPV1, which suggests that this pharmacological aspect of vanilloids can be dissociated from its potency. This finding raises the intriguing possibility that piperine can be used as a chemical template for the design of improved TRPV1 agonists.

Single-residue molecular switch for high-temperature dependence of vanilloid receptor TRPV3

PubMed Central

Liu, Beiying; Qin, Feng

2017-01-01

Thermal transient receptor potential (TRP) channels, a group of ion channels from the transient receptor potential family, play important functions in pain and thermal sensation. These channels are directly activated by temperature and possess strong temperature dependence. Furthermore, their temperature sensitivity can be highly dynamic and use-dependent. For example, the vanilloid receptor transient receptor potential 3 (TRPV3), which has been implicated as a warmth detector, becomes responsive to warm temperatures only after intensive stimulation. Upon initial activation, the channel exhibits a high-temperature threshold in the noxious temperature range above 50 °C. This use dependence of heat sensitivity thus provides a mechanism for sensitization of thermal channels. However, how the channels acquire the use dependence remains unknown. Here, by comparative studies of chimeric channels between use-dependent and use-independent homologs, we have determined the molecular basis that underlies the use dependence of temperature sensitivity of TRPV3. Remarkably, the restoration of a single residue that is apparently missing in the use-dependent homologs could largely eliminate the use dependence of heat sensitivity of TRPV3. The location of the region suggests a mechanism of temperature-dependent gating of thermal TRP channels involving an intracellular region assembled around the TRP domain. PMID:28154143

Downregulation of Endothelial Transient Receptor Potential Vanilloid Type 4 Channel and Small-Conductance of Ca2+-Activated K+ Channels Underpins Impaired Endothelium-Dependent Hyperpolarization in Hypertension.

PubMed

Seki, Takunori; Goto, Kenichi; Kiyohara, Kanako; Kansui, Yasuo; Murakami, Noboru; Haga, Yoshie; Ohtsubo, Toshio; Matsumura, Kiyoshi; Kitazono, Takanari

2017-01-01

Endothelium-dependent hyperpolarization (EDH)-mediated responses are impaired in hypertension, but the underlying mechanisms have not yet been determined. The activation of small- and intermediate-conductance of Ca 2+ -activated K + channels (SK Ca and IK Ca ) underpins EDH-mediated responses. It was recently reported that Ca 2+ influx through endothelial transient receptor potential vanilloid type 4 channel (TRPV4) is a prerequisite for the activation of SK Ca /IK Ca in endothelial cells in specific beds. Here, we attempted to determine whether the impairment of EDH in hypertension is attributable to the dysfunction of TRPV4 and S/IK Ca , using isolated superior mesenteric arteries of 20-week-old stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched Wistar-Kyoto (WKY) rats. In the WKY arteries, EDH-mediated responses were reduced by a combination of SK Ca /IK Ca blockers (apamin plus TRAM-34; 1-[(2-chlorophenyl)diphenylmethl]-1H-pyrazole) and by the blockade of TRPV4 with the selective antagonist RN-1734 or HC-067047. In the SHRSP arteries, EDH-mediated hyperpolarization and relaxation were significantly impaired when compared with WKY. GSK1016790A, a selective TRPV4 activator, evoked robust hyperpolarization and relaxation in WKY arteries. In contrast, in SHRSP arteries, the GSK1016790A-evoked hyperpolarization was small and relaxation was absent. Hyperpolarization and relaxation to cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine, a selective SK Ca activator, were marginally decreased in SHRSP arteries compared with WKY arteries. The expression of endothelial TRPV4 and SK Ca protein was significantly decreased in the SHRSP mesenteric arteries compared with those of WKY, whereas function and expression of IK Ca were preserved in SHRSP arteries. These findings suggest that EDH-mediated responses are impaired in superior mesenteric arteries of SHRSP because of a reduction in both TRPV4 and SK Ca input to EDH. © 2016 American Heart Association, Inc.

Type III Nrg1 Back Signaling Enhances Functional TRPV1 along Sensory Axons Contributing to Basal and Inflammatory Thermal Pain Sensation

PubMed Central

Canetta, Sarah E.; Luca, Edlira; Pertot, Elyse; Role, Lorna W.; Talmage, David A.

2011-01-01

Type III Nrg1, a member of the Nrg1 family of signaling proteins, is expressed in sensory neurons, where it can signal in a bi-directional manner via interactions with the ErbB family of receptor tyrosine kinases (ErbB RTKs) [1]. Type III Nrg1 signaling as a receptor (Type III Nrg1 back signaling) can acutely activate phosphatidylinositol-3-kinase (PtdIns3K) signaling, as well as regulate levels of α7* nicotinic acetylcholine receptors, along sensory axons [2]. Transient receptor potential vanilloid 1 (TRPV1) is a cation-permeable ion channel found in primary sensory neurons that is necessary for the detection of thermal pain and for the development of thermal hypersensitivity to pain under inflammatory conditions [3]. Cell surface expression of TRPV1 can be enhanced by activation of PtdIns3K [4], [5], [6], making it a potential target for regulation by Type III Nrg1. We now show that Type III Nrg1 signaling in sensory neurons affects functional axonal TRPV1 in a PtdIns3K-dependent manner. Furthermore, mice heterozygous for Type III Nrg1 have specific deficits in their ability to respond to noxious thermal stimuli and to develop capsaicin-induced thermal hypersensitivity to pain. Cumulatively, these results implicate Type III Nrg1 as a novel regulator of TRPV1 and a molecular mediator of nociceptive function. PMID:21949864

Topical Mannitol Reduces Capsaicin-Induced Pain: Results of a Pilot-Level, Double-Blind, Randomized Controlled Trial.

PubMed

Bertrand, Helene; Kyriazis, Marylene; Reeves, K Dean; Lyftogt, John; Rabago, David

2015-11-01

Capsaicin specifically activates, and then gradually exhausts, the transient receptor potential vanilloid type 1 (TRPV1) receptor, a key receptor in neuropathic pain. Activation of the TRPV-1 receptor is accompanied by burning pain. A natural substance or medication that can reduce the burning pain resulting from capsaicin application may have therapeutic potential in neuropathic pain. To assess the pain-relieving effects of a mannitol-containing cream in a capsaicin-based pain model. Randomized, placebo-controlled, double-blind clinical trial. Outpatient pain clinic. Twenty-five adults with pain-free lips. Capsaicin .075% cream was applied to both halves of each participant's upper lip, inducing pain via stimulation of the transient receptor potential vanilloid 1 (TRPV1, capsaicin) receptor, then removed after 5 minutes or when participants reported a burning pain of 8/10, whichever came first. A cream containing mannitol and the same cream without mannitol (control) were then immediately applied, 1 on each side of the lip, in an allocation-masked manner. Participants self-recorded a numeric rating scale (NRS, 0-10) pain score for each side of the lip per minute for 10 minutes. A t-test was performed to evaluate the pain score change from baseline between each side of the lip at each recording. Area under the curve (AUC) analysis was used to determine the overall difference between groups. Participants reached a capsaicin-induced pain level of 7.8 ± 1.0 points in 3.3 ± 1.6 minutes that was equal on both sides of the lip. Both groups reported progressive diminution of pain over the 10-minute study period. However, participants reported significantly reduced pain scores on the mannitol cream half-lip compared to control at 3 through 10 minutes (P < .05) and in AUC analysis (P < .001). Mannitol cream reduced self-reported pain scores in a capsaicin pain model more rapidly than a control cream, potentially via a TRPV1 receptor effect. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Ionotropic and metabotropic receptor mediated airway sensory nerve activation.

PubMed

Lee, Min-Goo; Kollarik, Marian; Chuaychoo, Benjamas; Undem, Bradley J

2004-01-01

There are several receptors capable of inducing activating generator potentials in cough-associated afferent terminals in the airways. The chemical receptors leading to generator potentials can be subclassified into ionotropic and metabotropic types. An ionotropic receptor has an agonist-binding domain, and also serves directly as an ion channel that is opened upon binding of the agonist. Examples of ionotropic receptors found in airway sensory nerve terminals include receptors for serotonin (5-HT3 receptors), ATP (P2X receptors), acetylcholine (nicotinic receptors), receptors for capsaicin and related vanilloids (TRPV1 receptors), and acid receptors (acid sensing ion channels). Afferent nerve terminals can also be depolarized via activation of metabotropic or G-protein coupled receptors (GPCRs). Among the GPCRs that can lead to activation of airway afferent fibers include bradykinin B2 and adenosine A1 receptors. The signaling events leading to GPCR-mediated membrane depolarization are more complex than that seen with ionotropic receptors. The GPCR-mediated effects are thought to occur through classical second messenger systems such as activation of phospholipase C. This may lead to membrane depolarization through interaction with specific ionotropic receptors (such as TRPV1) and/or various types of calcium activated channels.

Molecular Cloning and Functional Characterization of Xenopus tropicalis Frog Transient Receptor Potential Vanilloid 1 Reveal Its Functional Evolution for Heat, Acid, and Capsaicin Sensitivities in Terrestrial Vertebrates*

PubMed Central

Ohkita, Masashi; Saito, Shigeru; Imagawa, Toshiaki; Takahashi, Kenji; Tominaga, Makoto; Ohta, Toshio

2012-01-01

The functional difference of thermosensitive transient receptor potential (TRP) channels in the evolutionary context has attracted attention, but thus far little information is available on the TRP vanilloid 1 (TRPV1) function of amphibians, which diverged earliest from terrestrial vertebrate lineages. In this study we cloned Xenopus tropicalis frog TRPV1 (xtTRPV1), and functional characterization was performed using HeLa cells heterologously expressing xtTRPV1 (xtTRPV1-HeLa) and dorsal root ganglion neurons isolated from X. tropicalis (xtDRG neurons) by measuring changes in the intracellular calcium concentration ([Ca2+]i). The channel activity was also observed in xtTRPV1-expressing Xenopus oocytes. Furthermore, we tested capsaicin- and heat-induced nocifensive behaviors of the frog X. tropicalis in vivo. At the amino acid level, xtTRPV1 displays ∼60% sequence identity to other terrestrial vertebrate TRPV1 orthologues. Capsaicin induced [Ca2+]i increases in xtTRPV1-HeLa and xtDRG neurons and evoked nocifensive behavior in X. tropicalis. However, its sensitivity was extremely low compared with mammalian orthologues. Low extracellular pH and heat activated xtTRPV1-HeLa and xtDRG neurons. Heat also evoked nocifensive behavior. In oocytes expressing xtTRPV1, inward currents were elicited by heat and low extracellular pH. Mutagenesis analysis revealed that two amino acids (tyrosine 523 and alanine 561) were responsible for the low sensitivity to capsaicin. Taken together, our results indicate that xtTRPV1 functions as a polymodal receptor similar to its mammalian orthologues. The present study demonstrates that TRPV1 functions as a heat- and acid-sensitive channel in the ancestor of terrestrial vertebrates. Because it is possible to examine vanilloid and heat sensitivities in vitro and in vivo, X. tropicalis could be the ideal experimental lower vertebrate animal for the study of TRPV1 function. PMID:22130664

Role of the Outer Pore Domain in Transient Receptor Potential Vanilloid 1 Dynamic Permeability to Large Cations*

PubMed Central

Munns, Clare H.; Chung, Man-Kyo; Sanchez, Yuly E.; Amzel, L. Mario; Caterina, Michael J.

2015-01-01

Transient receptor potential vanilloid 1 (TRPV1) has been shown to alter its ionic selectivity profile in a time- and agonist-dependent manner. One hallmark of this dynamic process is an increased permeability to large cations such as N-methyl-d-glucamine (NMDG). In this study, we mutated residues throughout the TRPV1 pore domain to identify loci that contribute to dynamic large cation permeability. Using resiniferatoxin (RTX) as the agonist, we identified multiple gain-of-function substitutions within the TRPV1 pore turret (N628P and S629A), pore helix (F638A), and selectivity filter (M644A) domains. In all of these mutants, maximum NMDG permeability was substantially greater than that recorded in wild type TRPV1, despite similar or even reduced sodium current density. Two additional mutants, located in the pore turret (G618W) and selectivity filter (M644I), resulted in significantly reduced maximum NMDG permeability. M644A and M644I also showed increased and decreased minimum NMDG permeability, respectively. The phenotypes of this panel of mutants were confirmed by imaging the RTX-evoked uptake of the large cationic fluorescent dye YO-PRO1. Whereas none of the mutations selectively altered capsaicin-induced changes in NMDG permeability, the loss-of-function phenotypes seen with RTX stimulation of G618W and M644I were recapitulated in the capsaicin-evoked YO-PRO1 uptake assay. Curiously, the M644A substitution resulted in a loss, rather than a gain, in capsaicin-evoked YO-PRO1 uptake. Modeling of our mutations onto the recently determined TRPV1 structure revealed several plausible mechanisms for the phenotypes observed. We conclude that side chain interactions at a few specific loci within the TRPV1 pore contribute to the dynamic process of ionic selectivity. PMID:25568328

Role of the outer pore domain in transient receptor potential vanilloid 1 dynamic permeability to large cations.

PubMed

Munns, Clare H; Chung, Man-Kyo; Sanchez, Yuly E; Amzel, L Mario; Caterina, Michael J

2015-02-27

Transient receptor potential vanilloid 1 (TRPV1) has been shown to alter its ionic selectivity profile in a time- and agonist-dependent manner. One hallmark of this dynamic process is an increased permeability to large cations such as N-methyl-D-glucamine (NMDG). In this study, we mutated residues throughout the TRPV1 pore domain to identify loci that contribute to dynamic large cation permeability. Using resiniferatoxin (RTX) as the agonist, we identified multiple gain-of-function substitutions within the TRPV1 pore turret (N628P and S629A), pore helix (F638A), and selectivity filter (M644A) domains. In all of these mutants, maximum NMDG permeability was substantially greater than that recorded in wild type TRPV1, despite similar or even reduced sodium current density. Two additional mutants, located in the pore turret (G618W) and selectivity filter (M644I), resulted in significantly reduced maximum NMDG permeability. M644A and M644I also showed increased and decreased minimum NMDG permeability, respectively. The phenotypes of this panel of mutants were confirmed by imaging the RTX-evoked uptake of the large cationic fluorescent dye YO-PRO1. Whereas none of the mutations selectively altered capsaicin-induced changes in NMDG permeability, the loss-of-function phenotypes seen with RTX stimulation of G618W and M644I were recapitulated in the capsaicin-evoked YO-PRO1 uptake assay. Curiously, the M644A substitution resulted in a loss, rather than a gain, in capsaicin-evoked YO-PRO1 uptake. Modeling of our mutations onto the recently determined TRPV1 structure revealed several plausible mechanisms for the phenotypes observed. We conclude that side chain interactions at a few specific loci within the TRPV1 pore contribute to the dynamic process of ionic selectivity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Expression and diagnosis of transient receptor potential vanilloid1 in urothelium of patients with overactive bladder.

PubMed

Zhang, H Y; Chu, J F; Li, P; Li, N; Lv, Z H

2015-01-01

This study was carried out to test expression of transient receptor potential vanilloid1 (TRPV1) in urothelium of female patients with overactive bladder (OAB) and explore clinical significance of TRPV1 in diagnosing female OAB. TRPV1 expression in urothelium of female OAB patients (n=21) and healthy females (n=9) was detected using Strept Avidin-Biotin Complex (SABC), an immunohistochemical method and image analysis system. Relative content of TRPV1 was expressed by average optical density (AOD) and was analyzed through data of urodynamics. Compared to TRPV1 expression in urothelium of healthy females (AOD 0.3658 ± 0.1009), TRPV1 expression in OAB patients was much higher (AOD 0.4834 ± 0.1252) and the difference was significant P less than 0.05. Observation and comparison in clinic of urodynamic parameters of female patients and healthy females revealed that the former had lower indexes with remarkable differences (P less than 0.05) such as Qmax, first desire volume (FDV), strong desire volume (SDV), maximum cyst capacity (MCC) and bladder compliance (BC). Thus high expression of TRPV1 in urothelium of female OAB patients is closely correlated to OAB occurrence, showing great importance of improved bladder sensitivity in female OAB occurrence mechanism.

Nerve Growth Factor Regulates Transient Receptor Potential Vanilloid 2 via Extracellular Signal-Regulated Kinase Signaling To Enhance Neurite Outgrowth in Developing Neurons

PubMed Central

Cohen, Matthew R.; Johnson, William M.; Pilat, Jennifer M.; Kiselar, Janna; DeFrancesco-Lisowitz, Alicia; Zigmond, Richard E.

2015-01-01

Neurite outgrowth is key to the formation of functional circuits during neuronal development. Neurotrophins, including nerve growth factor (NGF), increase neurite outgrowth in part by altering the function and expression of Ca2+-permeable cation channels. Here we report that transient receptor potential vanilloid 2 (TRPV2) is an intracellular Ca2+-permeable TRPV channel upregulated by NGF via the mitogen-activated protein kinase (MAPK) signaling pathway to augment neurite outgrowth. TRPV2 colocalized with Rab7, a late endosome protein, in addition to TrkA and activated extracellular signal-regulated kinase (ERK) in neurites, indicating that the channel is closely associated with signaling endosomes. In line with these results, we showed that TRPV2 acts as an ERK substrate and identified the motifs necessary for phosphorylation of TRPV2 by ERK. Furthermore, neurite length, TRPV2 expression, and TRPV2-mediated Ca2+ signals were reduced by mutagenesis of these key ERK phosphorylation sites. Based on these findings, we identified a previously uncharacterized mechanism by which ERK controls TRPV2-mediated Ca2+ signals in developing neurons and further establish TRPV2 as a critical intracellular ion channel in neuronal function. PMID:26416880

Berberine via suppression of transient receptor potential vanilloid 4 channel improves vascular stiffness in mice

PubMed Central

Wang, Jie; Guo, Tao; Peng, Qi-Sheng; Yue, Shou-Wei; Wang, Shuang-Xi

2015-01-01

Berberine, as an alkaloid found in many Chinese herbs, improves vascular functions in patients with cardiovascular diseases. We determined the effects of berberine in hypertension and vascular ageing, and elucidated the underlying mechanisms. In isolated aortas, berberine dose-dependently elicited aortic relaxation. In cultured cells, berberine induced the relaxation of vascular smooth muscle cells (VSMCs). Overexpression of transient receptor potential vanilloid 4 (TRPV4) channel by genetic approaches abolished the berberine-induced reduction in intracellular Ca2+ concentration in VSMCs and attenuated berberine-elicited vessel dilation in mice aortas. In deoxycorticosterone acetate (DOCA)-induced hypertensive model, treatment of mice with berberine or RN-1734, a pharmacological inhibitor of TRPV4, significantly decreased systemic blood pressure (BP) in control mice or mice infected with an adenovirus vector. However, berberine-induced effects of lowering BP were reversed by overexpressing TRPV4 in mice by infecting with adenovirus. Furthermore, long-term administration of berberine decreased mean BP and pulse BP, increased artery response to vasodilator and reduced vascular collagen content in aged mice deficient in apolipoprotein E (Apoe-KO), but not in Apoe-KO old mice with lentivirus-mediated overexpression of TRPV4 channel. In conclusion, berberine induces direct vasorelaxation to lower BP and reduces vascular stiffness in aged mice through suppression of TRPV4. PMID:26177349

Measurement of Basal and Forskolin-stimulated Lipolysis in Inguinal Adipose Fat Pads.

PubMed

Baskaran, Padmamalini; Thyagarajan, Baskaran

2017-07-21

Lipolysis is a process by which the lipid stored as triglycerides in adipose tissues are hydrolyzed into glycerol and fatty acids. This article describes the method for the measurement of basal and forskolin (FSK)-stimulated lipolysis in the inguinal fat pads isolated from wild type mice fed either normal chow diet (NCD), high fat diet (HFD) or a high fat diet containing 0.01% of capsaicin (CAP; transient receptor potential vanilloid subfamily 1 (TRPV1) agonist) for 32 weeks. The method described here for performing ex vivo lipolysis is adopted from Schweiger et al. 1 We present a detailed protocol for measuring glycerol levels by UV-Visible (UV/VIS) spectrophotometry. The method described here can be used to successfully isolate inguinal fat pads for lipolysis measurements to obtain consistent results. The protocol described for inguinal fat pads can readily be extended to measure lipolysis in other tissues.

Role of Piezo Channels in Joint Health and Injury.

PubMed

Lee, W; Guilak, F; Liedtke, W

2017-01-01

Cartilage is an intrinsically mechanically sensitive tissue composed of chondrocytes as the only cell type. Chondrocyte mechanotransduction is not well understood, but recently we identified critical components of the mechanotransduction machinery demonstrating how mechanical stimulation of these cells can be converted into cellular calcium signals. Physiologic mechanical cues induce anabolic responses of (post-mitotic) chondrocytes via transient receptor potential vanilloid 4 ion channels, whereas injurious mechanical stress is transduced by Piezo1 jointly with Piezo2 ion channels. This chapter sheds light on the latter discovery and provides a rationale for follow-up questions, such as the nature of interaction between Piezo1 and Piezo2, and their tethering to the cytoskeleton. These recent insights can be leveraged toward translational medical progress to benefit diagnosis and treatment of osteoarthritis, representing a large and growing unmet medical need in the United States and large parts of the world. Copyright © 2017 Elsevier Inc. All rights reserved.

Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A.

PubMed

Charrua, Ana; Avelino, António; Cruz, Francisco

2011-01-01

The persisting interest around neurotoxins such as vanilloids and botulinum toxin (BoNT) derives from their marked effect on detrusor overactivity refractory to conventional antimuscarinic treatments. In addition, both are administered by intravesical route. This offers three potential advantages. First, intravesical therapy is an easy way to provide high concentrations of pharmacological agents in the bladder tissue without causing unsuitable levels in other organs. Second, drugs effective on the bladder, but inappropriate for systemic administration, can be safely used as it is the case of vanilloids and BoNT. Third, the effects of one single treatment might be extremely longlasting, contributing to render these therapies highly attractive to patients despite the fact that the reasons to the prolonged effect are still incompletely understood. Attractive as it may be, intravesical pharmacological therapy should still be considered as a second-line treatment in patients refractory to conventional oral antimuscarinic therapy or who do not tolerate its systemic side effects. However, the increasing off-label use of these neurotoxins justifies a reappraisal of their pharmacological properties.

Rational design and validation of a vanilloid-sensitive TRPV2 ion channel.

PubMed

Yang, Fan; Vu, Simon; Yarov-Yarovoy, Vladimir; Zheng, Jie

2016-06-28

Vanilloids activation of TRPV1 represents an excellent model system of ligand-gated ion channels. Recent studies using cryo-electron microcopy (cryo-EM), computational analysis, and functional quantification revealed the location of capsaicin-binding site and critical residues mediating ligand-binding and channel activation. Based on these new findings, here we have successfully introduced high-affinity binding of capsaicin and resiniferatoxin to the vanilloid-insensitive TRPV2 channel, using a rationally designed minimal set of four point mutations (F467S-S498F-L505T-Q525E, termed TRPV2_Quad). We found that binding of resiniferatoxin activates TRPV2_Quad but the ligand-induced open state is relatively unstable, whereas binding of capsaicin to TRPV2_Quad antagonizes resiniferatoxin-induced activation likely through competition for the same binding sites. Using Rosetta-based molecular docking, we observed a common structural mechanism underlying vanilloids activation of TRPV1 and TRPV2_Quad, where the ligand serves as molecular "glue" that bridges the S4-S5 linker to the S1-S4 domain to open these channels. Our analysis revealed that capsaicin failed to activate TRPV2_Quad likely due to structural constraints preventing such bridge formation. These results not only validate our current working model for capsaicin activation of TRPV1 but also should help guide the design of drug candidate compounds for this important pain sensor.

U.S. Army Aeromedical Research Laboratory Annual Progress Report Fiscal Year 2010

DTIC Science & Technology

2011-03-01

S. (2010). Epidermal growth factor receptor transactivation by the cannabinoid receptor (CB1) and transient receptor potential vanilloid 1 ( TRPV1 ...induced by TRPV1 in human corneal epithelial cells. Proceedings of the Association for Research in Vision and Ophthalmology Annual Meeting, 5899/A94...presented “Novel TRPV1 -linked cell signaling pathways mediating inflammatory responses and wound healing in human corneal epithelial cells” at the Fouth

Stretch-activated TRPV2 channels: Role in mediating cardiopathies.

PubMed

Aguettaz, Elizabeth; Bois, Patrick; Cognard, Christian; Sebille, Stéphane

2017-11-01

Transient receptor potential vanilloid type 2, TRPV2, is a calcium-permeable cation channel belonging to the TRPV channel family. Although this channel has been first characterized as a noxious heat sensor, its mechanosensor property recently gained importance in various physiological functions. TRPV2 has been described as a stretch-mediated channel and a regulator of calcium homeostasis in several cell types and has been shown to be involved in the stretch-dependent responses in cardiomyocytes. Hence, several studies in the last years support the idea that TRPV2 play a key role in the function and structure of the heart, being involved in the cardiac compensatory mechanisms in response to pathologic or exercise-induced stress. We present here an overview of the current literature and concepts of TRPV2 channels involvement (i) in the mechanical coupling mechanisms in heart and (ii) in the mechanisms that lead to cardiomyopathies. All these studies lead us to think that TRPV2 may also be an important cardiac drug target based on its major physiological roles in heart. Copyright © 2017 Elsevier Ltd. All rights reserved.

Expression Profiling of the Transient Receptor Potential Vanilloid (TRPV) Channels 1, 2, 3 and 4 in Mucosal Epithelium of Human Ulcerative Colitis.

PubMed

Rizopoulos, Theodoros; Papadaki-Petrou, Helen; Assimakopoulou, Martha

2018-06-15

The Transient Receptor Potential (TRP) family of selective and non-selective ion channels is well represented throughout the mammalian gastrointestinal track. Several members of the Transient Receptor Potential Vanilloid (TRPV) subfamily have been identified in contributing to modulation of mobility, secretion and sensitivity of the human intestine. Previous studies have focused on the detection of TRPV mRNA levels in colon tissue of patients with inflammatory bowel disease (IBD) whereas little information exists regarding TRPV channel expression in the colonic epithelium. The aim of this study was to evaluate the expression levels of TRPV1, TRPV2, TRPV3 and TRPV4 in mucosa epithelial cells of colonic biopsies from patients with ulcerative colitis (UC) in comparison to colonic resections from non-IBD patients (control group). Immunohistochemistry, using specific antibodies and quantitative analyses of TRPV-immunostained epithelial cells, was performed in semi-serial sections of the samples. TRPV1 expression was significantly decreased whereas TRPV4 expression was significantly increased in the colonic epithelium of UC patients compared to patients in the control group ( p < 0.05). No significant difference for TRPV2 and TRPV3 expression levels between UC and control specimens was detected ( p > 0.05). There was no correlation between TRPV channel expression and the clinical features of the disease ( p > 0.05). Further investigation is needed to clarify the role of TRPV channels in human bowel inflammatory response.

Forsythoside A exerts antipyretic effect on yeast-induced pyrexia mice via inhibiting transient receptor potential vanilloid 1 function

PubMed Central

Liu, Cuiling; Su, Hongchang; Wan, Hongye; Qin, Qingxia; Wu, Xuan; Kong, Xiangying; Lin, Na

2017-01-01

Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel gated by noxious heat, playing major roles in thermoregulation. Forsythoside A (FT-A) is the most abundant phenylethanoid glycosides in Fructus Forsythiae, which has been prescribed as a medicinal herb for treating fever in China for a long history. However, how FT-A affects pyrexia and what is the underlying molecular mechanism remain largely unknown. Here we found that FT-A exerted apparent antipyretic effect through decreasing the levels of prostaglandin E2 (PGE2) and interleukin 8 (IL-8) in a dose-dependent fashion on the yeast induced pyrexia mice. Interestingly, FT-A significantly downregulated TRPV1 expression in the hypothalamus and dorsal root ganglion (DRG) of the yeast induced pyrexia mice. Moreover, FT-A inhibited IL-8 and PGE2 secretions, and calcium influx in the HEK 293T-TRPV1 cells after stimulated with capsaicin, the specific TRPV1 agonist. Further investigation of the molecular mechanisms revealed that FT-A treatment rapidly inhibited phosphorylation of extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 in both yeast induced pyrexia mice and HEK 293T-TRPV1 cells. These results suggest that FT-A may serve as a potential antipyretic agent and the therapeutic action of Fructus Forsythiae on pyretic related disease is, in part, due to the FT-A activities. PMID:28123347

Transient receptor potential vanilloid-3 (TRPV3) activation plays a central role in cardiac fibrosis induced by pressure overload in rats via TGF-β1 pathway.

PubMed

Liu, Yan; Qi, Hanping; E, Mingyao; Shi, Pilong; Zhang, Qianhui; Li, Shuzhi; Wang, Ye; Cao, Yonggang; Chen, Yunping; Ba, Lina; Gao, Jingquan; Huang, Wei; Sun, Hongli

2018-02-01

Cardiac fibrosis is a common pathologic change along with pressure overload. Recent studies indicated that transient receptor potential (TRP) channels played multiple roles in heart. However, the functional role of transient receptor potential vanilloid-3 (TRPV3) in cardiac fibrosis remained unclear. The present study was designed to investigate the relationship between TRPV3 activation and pressure overload-induced cardiac fibrosis. Pressure overload rats were successfully established by abdominal aortic constriction (AAC), and cardiac fibrosis was simulated by 100 nM angiotensin II (Ang II) in neonatal cardiac fibroblasts. Echocardiographic parameters, cardiac fibroblast proliferation, cell cycle, intracellular calcium concentration ([Ca 2+ ] i ), and the protein expressions of collagen I, collagen III, transforming growth factor beta 1 (TGF-β 1 ), cyclin E, and cyclin-dependent kinase 2 (CDK2) were measured. Echocardiographic and histological measurements suggested that the activation of TRPV3 exacerbated the cardiac dysfunction and increased interstitial fibrosis in pressure overload rats. Further results showed that TRPV3 activation upregulated the expressions of collagen I, collagen III, TGF-β 1 , cyclin E, and CDK2 in vivo and in vitro. At the same time, blocking TGF-β 1 pathway could partially reverse the effect of TRPV3 activation. These results suggested that TRPV3 activation exacerbated cardiac fibrosis by promoting cardiac fibroblast proliferation through TGF-β 1 /CDK2/cyclin E pathway in the pressure-overloaded rat hearts.

Capsaicin in Metabolic Syndrome

PubMed Central

Bliss, Edward

2018-01-01

Capsaicin, the major active constituent of chilli, is an agonist on transient receptor potential vanilloid channel 1 (TRPV1). TRPV1 is present on many metabolically active tissues, making it a potentially relevant target for metabolic interventions. Insulin resistance and obesity, being the major components of metabolic syndrome, increase the risk for the development of cardiovascular disease, type 2 diabetes, and non-alcoholic fatty liver disease. In vitro and pre-clinical studies have established the effectiveness of low-dose dietary capsaicin in attenuating metabolic disorders. These responses of capsaicin are mediated through activation of TRPV1, which can then modulate processes such as browning of adipocytes, and activation of metabolic modulators including AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α (PPARα), uncoupling protein 1 (UCP1), and glucagon-like peptide 1 (GLP-1). Modulation of these pathways by capsaicin can increase fat oxidation, improve insulin sensitivity, decrease body fat, and improve heart and liver function. Identifying suitable ways of administering capsaicin at an effective dose would warrant its clinical use through the activation of TRPV1. This review highlights the mechanistic options to improve metabolic syndrome with capsaicin. PMID:29772784

Capsaicin in Metabolic Syndrome.

PubMed

Panchal, Sunil K; Bliss, Edward; Brown, Lindsay

2018-05-17

Capsaicin, the major active constituent of chilli, is an agonist on transient receptor potential vanilloid channel 1 (TRPV1). TRPV1 is present on many metabolically active tissues, making it a potentially relevant target for metabolic interventions. Insulin resistance and obesity, being the major components of metabolic syndrome, increase the risk for the development of cardiovascular disease, type 2 diabetes, and non-alcoholic fatty liver disease. In vitro and pre-clinical studies have established the effectiveness of low-dose dietary capsaicin in attenuating metabolic disorders. These responses of capsaicin are mediated through activation of TRPV1, which can then modulate processes such as browning of adipocytes, and activation of metabolic modulators including AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α (PPARα), uncoupling protein 1 (UCP1), and glucagon-like peptide 1 (GLP-1). Modulation of these pathways by capsaicin can increase fat oxidation, improve insulin sensitivity, decrease body fat, and improve heart and liver function. Identifying suitable ways of administering capsaicin at an effective dose would warrant its clinical use through the activation of TRPV1. This review highlights the mechanistic options to improve metabolic syndrome with capsaicin.

Pregnancy-induced remodelling and enhanced endothelium-derived hyperpolarization-type vasodilator activity in rat uterine radial artery: transient receptor potential vanilloid type 4 channels, caveolae and myoendothelial gap junctions

PubMed Central

Senadheera, Sevvandi; Bertrand, Paul P; Grayson, T Hilton; Leader, Leo; Murphy, Timothy V; Sandow, Shaun L

2013-01-01

In pregnancy, the vasculature of the uterus undergoes rapid remodelling to increase blood flow and maintain perfusion to the fetus. The present study determines the distribution and density of caveolae, transient receptor potential vanilloid type 4 channels (TRPV4) and myoendothelial gap junctions, and the relative contribution of related endothelium-dependent vasodilator components in uterine radial arteries of control virgin non-pregnant and 20-day late-pregnant rats. The hypothesis examined is that specific components of endothelium-dependent vasodilator mechanisms are altered in pregnancy-related uterine radial artery remodelling. Conventional and serial section electron microscopy were used to determine the morphological characteristics of uterine radial arteries from control and pregnant rats. TRPV4 distribution and expression was examined using conventional confocal immunohistochemistry, and the contribution of endothelial TRPV4, nitric oxide (NO) and endothelium-derived hyperpolarization (EDH)-type activity determined using pressure myography with pharmacological intervention. Data show outward hypertrophic remodelling occurs in uterine radial arteries in pregnancy. Further, caveolae density in radial artery endothelium and smooth muscle from pregnant rats was significantly increased by ∼94% and ∼31%, respectively, compared with control, whereas caveolae density did not differ in endothelium compared with smooth muscle from control. Caveolae density was significantly higher by ∼59% on the abluminal compared with the luminal surface of the endothelium in uterine radial artery of pregnant rats but did not differ at those surfaces in control. TRPV4 was present in endothelium and smooth muscle, but not associated with internal elastic lamina hole sites in radial arteries. TRPV4 fluorescence intensity was significantly increased in the endothelium and smooth muscle of radial artery of pregnant compared with control rats by ∼2.6- and 5.5-fold, respectively. The TRPV4 signal was significantly higher in the endothelium compared with the smooth muscle in radial artery of both control and pregnant rats, by ∼5.7- and 2.7-fold, respectively. Myoendothelial gap junction density was significantly decreased by ∼37% in radial artery from pregnant compared with control rats. Pressure myography with pharmacological intervention showed that NO contributes ∼80% and ∼30%, and the EDH-type component ∼20% and ∼70% of the total endothelium-dependent vasodilator response in radial arteries of control and pregnant rats, respectively. TRPV4 plays a functional role in radial arteries, with a greater contribution in those from pregnant rats. The correlative association of increased TRPV4 and caveolae density and role of EDH-type activity in uterine radial artery of pregnant rats is suggestive of their causal relationship. The decreased myoendothelial gap junction density and lack of TRPV4 density at such sites is consistent with their having an integral, albeit complex, interactive role in uterine vascular signalling and remodelling in pregnancy. PMID:24128141

Modulation of neuroinflammation: Role and therapeutic potential of TRPV1 in the neuro-immune axis.

PubMed

Kong, Wei-Lin; Peng, Yuan-Yuan; Peng, Bi-Wen

2017-08-01

Transient receptor potential vanilloid type 1 channel (TRPV1), as a ligand-gated non-selective cation channel, has recently been demonstrated to have wide expression in the neuro-immune axis, where its multiple functions occur through regulation of both neuronal and non-neuronal activities. Growing evidence has suggested that TRPV1 is functionally expressed in glial cells, especially in the microglia and astrocytes. Glial cells perform immunological functions in response to pathophysiological challenges through pro-inflammatory or anti-inflammatory cytokines and chemokines in which TRPV1 is involved. Sustaining inflammation might mediate a positive feedback loop of neuroinflammation and exacerbate neurological disorders. Accumulating evidence has suggested that TRPV1 is closely related to immune responses and might be recognized as a molecular switch in the neuroinflammation of a majority of seizures and neurodegenerative diseases. In this review, we evidenced that inflammation modulates the expression and activity of TRPV1 in the central nervous system (CNS) and TRPV1 exerts reciprocal actions over neuroinflammatory processes. Together, the literature supports the hypothesis that TRPV1 may represent potential therapeutic targets in the neuro-immune axis. Copyright © 2017 Elsevier Inc. All rights reserved.

The evolution and comparative neurobiology of endocannabinoid signalling

PubMed Central

Elphick, Maurice R.

2012-01-01

CB1- and CB2-type cannabinoid receptors mediate effects of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide in mammals. In canonical endocannabinoid-mediated synaptic plasticity, 2-AG is generated postsynaptically by diacylglycerol lipase alpha and acts via presynaptic CB1-type cannabinoid receptors to inhibit neurotransmitter release. Electrophysiological studies on lampreys indicate that this retrograde signalling mechanism occurs throughout the vertebrates, whereas system-level studies point to conserved roles for endocannabinoid signalling in neural mechanisms of learning and control of locomotor activity and feeding. CB1/CB2-type receptors originated in a common ancestor of extant chordates, and in the sea squirt Ciona intestinalis a CB1/CB2-type receptor is targeted to axons, indicative of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling. Although CB1/CB2-type receptors are unique to chordates, enzymes involved in biosynthesis/inactivation of endocannabinoids occur throughout the animal kingdom. Accordingly, non-CB1/CB2-mediated mechanisms of endocannabinoid signalling have been postulated. For example, there is evidence that 2-AG mediates retrograde signalling at synapses in the nervous system of the leech Hirudo medicinalis by activating presynaptic transient receptor potential vanilloid-type ion channels. Thus, postsynaptic synthesis of 2-AG or anandamide may be a phylogenetically widespread phenomenon, and a variety of proteins may have evolved as presynaptic (or postsynaptic) receptors for endocannabinoids. PMID:23108540

The Transient Receptor Potential Vanilloid 1 Antagonist Capsazepine Improves the Impaired Lung Mechanics during Endotoxemia.

PubMed

Cabral, Layla D M; Giusti-Paiva, Alexandre

2016-11-01

Acute lung injury (ALI) caused by systemic inflammatory response remains a leading cause of morbidity and mortality in critically ill patients. Management of patients with sepsis is largely limited to supportive therapies, reflecting an incomplete understanding of the underlying pathophysiology. Furthermore, there have been limited advances in the treatments for ALI. In this study, lung function and a histological analysis were performed to evaluate the impact of transient receptor potential vanilloid-1 receptor (TRPV1) antagonist (capsazepine; CPZ) on the lipopolysaccharide (LPS)-induced lung injury in mice. For this, adult mice pre-treated with CPZ or vehicle received intraperitoneal injections of LPS or saline and 24 hr after, the mice were anaesthetized, and lung mechanics was evaluated. The LPS-challenged mice exhibited substantial mechanical impairment, characterized by increases in respiratory system resistance, respiratory system elastance, tissue damping and tissue elastance. The pre-treatment with CPZ prevented the increase in respiratory system resistance and decreased the increase in tissue damping during endotoxemia. In addition, mice pre-treated with CPZ had an attenuated lung injury evidenced by reduction on collapsed area of the lung parenchyma induced by LPS. This suggests that the TRPV1 antagonist capsazepine has a protective effect on lung mechanics in ALI during endotoxemia and that it may be a target for enhanced therapeutic efficacy in ALI. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Distribution profiles of transient receptor potential melastatin- and vanilloid-related channels in rat spermatogenic cells and sperm.

PubMed

Li, Shilin; Wang, Xinghuan; Ye, Haixia; Gao, Weicheng; Pu, Xiaoyong; Yang, Zhonghua

2010-03-01

In the present study, we aimed to investigate the expression and distribution of transient receptor potential melastatin (TRPM)- and vanilloid (TRPV)- related channels in rat spermatogenic cells and spermatozoa. Spermatogenic cells and spermatozoa were obtained from male Sprague-Dawley rats. Reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of all TRPM and TRPV channel members with specific primers. Western blot analysis was applied for detecting the expression of TRPM and TRPV channel proteins. Immunohistochemistry staining for TRPM4, TRPM7 and TRPV5 was also performed in rat testis. The mRNAs of TRPM3, TRPM4, TRPM7 and TRPV5 were detected in the spermatogenic cells and spermatozoa in rat. Western blot analysis verified the expression of TRPM4, TRPM7 and TRPV5 in the rat spermatogenic cells and spermatozoa. Immunocytochemistry staining for TRPM and TRPV channel families indicated that TRPM4 and TRPM7 proteins were highly expressed in different stages of spermatogenic cells and spermatozoa, while TRPV5 protein was lowly expressed in these cells. Our results demonstrate that mRNAs or proteins for TRPM3, TRPM4, TRPM7 and TRPV5 exist in rat spermatogenic cells and spermatozoa. These data presented here may assist in elucidating the possible physiological function of TRPM and TRPV channels in spermatogenic cells and spermatozoa.

Pharmacology of modality-specific transient receptor potential vanilloid-1 antagonists that do not alter body temperature.

PubMed

Reilly, Regina M; McDonald, Heath A; Puttfarcken, Pamela S; Joshi, Shailen K; Lewis, LaGeisha; Pai, Madhavi; Franklin, Pamela H; Segreti, Jason A; Neelands, Torben R; Han, Ping; Chen, Jun; Mantyh, Patrick W; Ghilardi, Joseph R; Turner, Teresa M; Voight, Eric A; Daanen, Jerome F; Schmidt, Robert G; Gomtsyan, Arthur; Kort, Michael E; Faltynek, Connie R; Kym, Philip R

2012-08-01

The transient receptor potential vanilloid-1 (TRPV1) channel is involved in the development and maintenance of pain and participates in the regulation of temperature. The channel is activated by diverse agents, including capsaicin, noxious heat (≥ 43°C), acidic pH (< 6), and endogenous lipids including N-arachidonoyl dopamine (NADA). Antagonists that block all modes of TRPV1 activation elicit hyperthermia. To identify efficacious TRPV1 antagonists that do not affect temperature antagonists representing multiple TRPV1 pharmacophores were evaluated at recombinant rat and human TRPV1 channels with Ca(2+) flux assays, and two classes of antagonists were identified based on their differential ability to inhibit acid activation. Although both classes of antagonists completely blocked capsaicin- and NADA-induced activation of TRPV1, select compounds only partially inhibited activation of the channel by protons. Electrophysiology and calcitonin gene-related peptide release studies confirmed the differential pharmacology of these antagonists at native TRPV1 channels in the rat. Comparison of the in vitro pharmacological properties of these TRPV1 antagonists with their in vivo effects on core body temperature confirms and expands earlier observations that acid-sparing TRPV1 antagonists do not significantly increase core body temperature. Although both classes of compounds elicit equivalent analgesia in a rat model of knee joint pain, the acid-sparing antagonist tested is not effective in a mouse model of bone cancer pain.

Involvement of transient receptor potential vanilloid 2 in intra-oral incisional pain.

PubMed

Urata, K; Shinoda, M; Ikutame, D; Iinuma, T; Iwata, K

2018-03-05

To examine whether transient receptor potential vanilloid 2 (TRPV2) contributes to the changes in intra-oral thermal and mechanical sensitivity following the incision of buccal mucosa. Buccal mucosal pain threshold was measured after the incision. Changes in the number of TRPV2-immunoreactive (IR) trigeminal ganglion (TG) neurons which innervate the whisker pad skin and buccal mucosa, changes in the number of isolectin B4-negative/isolectin B4-positive TRPV2-IR TG neurons which innervate the whisker pad skin and the buccal mucosa, and the effect of peripheral TRPV2 antagonism on the pain threshold of incisional whisker pad skin and buccal mucosa were examined after these injuries. Buccal mucosal pain hypersensitivities were induced on day 3 following the incision. The total number of TRPV2-IR TG neurons and the number of isolectin B4-negative TRPV2-IR TG neurons which innervate the whisker pad skin and buccal mucosa were increased. Buccal mucosal TRPV2 antagonism completely suppressed the heat and mechanical hypersensitivities, but not cold hypersensitivity. TRPV2 antagonist administration to the incisional whisker pad skin only partially suppressed pain hypersensitivities. The increased expression of TRPV2 in peptidergic TG neurons innervating the incisional buccal mucosa is predominantly involved in buccal mucosal heat hyperalgesia and mechanical allodynia following buccal mucosal incision. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.

[6]-Gingerol induces bone loss in ovary intact adult mice and augments osteoclast function via the transient receptor potential vanilloid 1 channel.

PubMed

Khan, Kainat; Singh, Akanksha; Mittal, Monika; Sharan, Kunal; Singh, Nidhi; Dixit, Preety; Sanyal, Sabyasachi; Maurya, Rakesh; Chattopadhyay, Naibedya

2012-12-01

[6]-Gingerol, a major constituent of ginger, is considered to have several health beneficial effects. The effect of 6-gingerol on bone cells and skeleton of mice was investigated. The effects of 6-gingerol on mouse bone marrow macrophages and osteoblasts were studied. 6-Gingerol-stimulated osteoclast differentiation of bone marrow macrophages but had no effect on osteoblasts. Capsazepine, an inhibitor of TRPV1 (transient receptor potential vanilloid 1) channel, attenuated the pro-osteoclastogenic effect of 6-gingerol or capsaicin (an agonist of TRPV1). Similar to capsaicin, 6-gingerol stimulated Ca(2) + influx in osteoclasts. The effect of daily feeding of 6-gingerol for 5 wk on the skeleton of adult female Balb/cByJ mice was investigated. Mice treated with capsaicin and ovariectomized (OVx) mice served as controls for osteopenia. 6-Gingerol caused increase in trabecular osteoclast number, microarchitectural erosion at all trabecular sites and loss of vertebral stiffness, and these effects were comparable to capsaicin or OVx group. Osteoclast-specific serum and gene markers of 6-gingerol-treated mice were higher than the OVx group. Bone formation was unaffected by 6-gingerol. Daily feeding of 6-gingerol to skeletally mature female mice caused trabecular osteopenia, and the mechanism appeared to be activation of osteoclast formation via the TRPV1 channel. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rational design and validation of a vanilloid-sensitive TRPV2 ion channel

PubMed Central

Yang, Fan; Vu, Simon; Yarov-Yarovoy, Vladimir; Zheng, Jie

2016-01-01

Vanilloids activation of TRPV1 represents an excellent model system of ligand-gated ion channels. Recent studies using cryo-electron microcopy (cryo-EM), computational analysis, and functional quantification revealed the location of capsaicin-binding site and critical residues mediating ligand-binding and channel activation. Based on these new findings, here we have successfully introduced high-affinity binding of capsaicin and resiniferatoxin to the vanilloid-insensitive TRPV2 channel, using a rationally designed minimal set of four point mutations (F467S–S498F–L505T–Q525E, termed TRPV2_Quad). We found that binding of resiniferatoxin activates TRPV2_Quad but the ligand-induced open state is relatively unstable, whereas binding of capsaicin to TRPV2_Quad antagonizes resiniferatoxin-induced activation likely through competition for the same binding sites. Using Rosetta-based molecular docking, we observed a common structural mechanism underlying vanilloids activation of TRPV1 and TRPV2_Quad, where the ligand serves as molecular “glue” that bridges the S4–S5 linker to the S1–S4 domain to open these channels. Our analysis revealed that capsaicin failed to activate TRPV2_Quad likely due to structural constraints preventing such bridge formation. These results not only validate our current working model for capsaicin activation of TRPV1 but also should help guide the design of drug candidate compounds for this important pain sensor. PMID:27298359

Targeting TRPV1 and TRPV2 for potential therapeutic interventions in cardiovascular disease.

PubMed

Robbins, Nathan; Koch, Sheryl E; Rubinstein, Jack

2013-06-01

Cardiovascular disease is a leading cause of morbidity and mortality worldwide, encompassing a variety of cardiac and vascular conditions. Transient receptor potential vanilloid (TRPV) channels, specifically TRPV type 1 (TRPV1) and TRPV type 2 (TRPV2), are relatively recently described channels found throughout the body including within and around the cardiovascular system. They are activated by a variety of stimuli including high temperatures, stretch, and pharmacologic and endogenous ligands. The TRPV1 channel has been found to be an important player in the pathway of the detection of chest pain after myocardial injury. Activation of peripheral TRPV1 via painful stimuli or capsaicin has been shown to have cardioprotective effects, whereas genetic abrogation of TRPV1 results in increased myocardial damage after ischemia and reperfusion injury in comparison to wild-type mice. Furthermore, blood pressure changes have been noted upon TRPV1 stimulation. Similarly, the TRPV2 channel has also been associated with changes in blood pressure and cardiac function depending on how and where the channel is activated. Interestingly, overexpression of TRPV2 channels in the heart induces dystrophic cardiomyopathy; however, stimulation under physiologic conditions leads to improved cardiac function. Probenecid, a TRPV2 agonist, has been studied as a model therapy for its inotropic effects and potential use in the treatment of cardiomyopathy. In this review, we present an up to date account of the growing evidence that supports the study of TRPV1 and TRPV2 channels as targets for therapeutic agents of cardiovascular diseases. Published by Mosby, Inc.

[Effect of high-fat diet on expression of transient receptor potential vanilloid 1 in respiratory tract and dorsal root ganglion of mice].

PubMed

Zhu, Lian; Xu, Zhi-Liang

2017-07-01

To investigate the effect of high-fat diet on the expression of transient receptor potential vanilloid 1 (TRPV1) in the respiratory system and the dorsal root ganglion (DRG) of mice, as well as its effect on the excitability of sensory neurons. A total of 20 C57BL/6 mice were randomly divided into normal-diet (ND) group and high-fat diet (HFD) group, with 10 mice in each group. The mice were given corresponding diets and body weights were monitored. After 7 weeks of feeding, lung tissue, bronchial tissue, and DRG at thoracic segments 3-4 were collected and immunohistochemical staining was performed. A patch clamp was used to measure the number of action potentials and TRPV1 current intensity in the DRG. After 7 weeks of feeding, the HFD group had significantly greater mean weight gain than the ND group (6.4±2.6 g vs 2.3±0.5 g; P<0.001). The HFD group had significantly higher expression of TRPV1 in the bronchus, pulmonary alveoli, and DRG than the ND group (P<0.05). Compared with the ND group, the HFD group had significant increases in the TRPV1 current intensity and number of action potentials in the DRG (P<0.05). High-fat diet induces a significant increase in body weight and leads to high expression of TRPV1 and high excitability in the respiratory system and the peripheral sensory neurons. This suggests that TRPV1 may be an important factor in the physiopathological mechanisms of bronchial hyperresponsiveness.

Transient receptor potential vanilloid 2 (TRPV2), a potential novel biomarker in childhood asthma.

PubMed

Cai, Xin; Yang, Yong-chang; Wang, Jing-feng; Wang, Qiang; Gao, Jie; Fu, Wen-liang; Zhu, Ze-yi; Wang, Yuan-yuan; Zou, Min-ji; Wang, Jia-xi; Xu, Dong-qun; Xu, Dong-gang

2013-03-01

The presence of transient receptor potential vanilloid 2 (TRPV2) in human peripheral blood cells may suggest a role under pathological conditions. The aim of this study was to explore the relationship between the expression profile of TRPV2 gene and childhood asthma in the north of China. The effects of allergens exposure on the expression of TRPV2 gene were also investigated. Sixty asthmatics children confirmed by physician diagnosis and 60 healthy children as a control group were recruited. Serum total IgE and specific IgE were measured. Using quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR), TRPV2 was detected in total RNA extracted from peripheral blood lymphocytes. Student's t-test and chi-square test were used to analyze the relationship between TRPV2 transcript and different parameter variables on susceptibility of childhood asthma. Multiple logistic regression was used to analyze the associations between TRPV2 gene and allergens. The expression level of TRPV2 gene was increased 2.6 times in asthmatic children compared with controls (p < .01). The up-regulation of TRPV2 gene and sensitization to one of three the allergens-spring pollen, dust mite, and dog and cat hair-were correlated with childhood asthma. In addition, the hypersensitivity to spring pollen, cockroach, and dust mite and up-regulation of TRPV2 gene expression may be the risk factors for the childhood asthma in Beijing. The increased expression of TRPV2 gene in peripheral lymphocytes is closely correlated with childhood asthma in the north of China. This study provides a potential new biomarker of childhood asthma and lays the basis for further clarification of the pathogenesis underlying asthma.

Plant-derived cannabinoids modulate the activity of transient receptor potential channels of ankyrin type-1 and melastatin type-8.

PubMed

De Petrocellis, Luciano; Vellani, Vittorio; Schiano-Moriello, Aniello; Marini, Pietro; Magherini, Pier Cosimo; Orlando, Pierangelo; Di Marzo, Vincenzo

2008-06-01

The plant cannabinoids (phytocannabinoids), cannabidiol (CBD), and Delta(9)-tetrahydrocannabinol (THC) were previously shown to activate transient receptor potential channels of both vanilloid type 1 (TRPV1) and ankyrin type 1 (TRPA1), respectively. Furthermore, the endocannabinoid anandamide is known to activate TRPV1 and was recently found to antagonize the menthol- and icilin-sensitive transient receptor potential channels of melastatin type 8 (TRPM8). In this study, we investigated the effects of six phytocannabinoids [i.e., CBD, THC, CBD acid, THC acid, cannabichromene (CBC), and cannabigerol (CBG)] on TRPA1- and TRPM8-mediated increase in intracellular Ca2+ in either HEK-293 cells overexpressing the two channels or rat dorsal root ganglia (DRG) sensory neurons. All of the compounds tested induced TRPA1-mediated Ca2+ elevation in HEK-293 cells with efficacy comparable with that of mustard oil isothiocyanates (MO), the most potent being CBC (EC(50) = 60 nM) and the least potent being CBG and CBD acid (EC(50) = 3.4-12.0 microM). CBC also activated MO-sensitive DRG neurons, although with lower potency (EC(50) = 34.3 microM). Furthermore, although none of the compounds tested activated TRPM8-mediated Ca2+ elevation in HEK-293 cells, they all, with the exception of CBC, antagonized this response when it was induced by either menthol or icilin. CBD, CBG, THC, and THC acid were equipotent (IC(50) = 70-160 nM), whereas CBD acid was the least potent compound (IC(50) = 0.9-1.6 microM). CBG inhibited Ca2+ elevation also in icilin-sensitive DRG neurons with potency (IC(50) = 4.5 microM) similar to that of anandamide (IC(50) = 10 microM). Our findings suggest that phytocannabinoids and cannabis extracts exert some of their pharmacological actions also by interacting with TRPA1 and TRPM8 channels, with potential implications for the treatment of pain and cancer.

Mechanisms of transient receptor potential vanilloid 1 activation and sensitization by allyl isothiocyanate.

PubMed

Gees, Maarten; Alpizar, Yeranddy A; Boonen, Brett; Sanchez, Alicia; Everaerts, Wouter; Segal, Andrei; Xue, Fenqin; Janssens, Annelies; Owsianik, Grzegorz; Nilius, Bernd; Voets, Thomas; Talavera, Karel

2013-09-01

Allyl isothiocyanate (AITC; aka, mustard oil) is a powerful irritant produced by Brassica plants as a defensive trait against herbivores and confers pungency to mustard and wasabi. AITC is widely used experimentally as an inducer of acute pain and neurogenic inflammation, which are largely mediated by the activation of nociceptive cation channels transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 (TRPV1). Although it is generally accepted that electrophilic agents activate these channels through covalent modification of cytosolic cysteine residues, the mechanism underlying TRPV1 activation by AITC remains unknown. Here we show that, surprisingly, AITC-induced activation of TRPV1 does not require interaction with cysteine residues, but is largely dependent on S513, a residue that is involved in capsaicin binding. Furthermore, AITC acts in a membrane-delimited manner and induces a shift of the voltage dependence of activation toward negative voltages, which is reminiscent of capsaicin effects. These data indicate that AITC acts through reversible interactions with the capsaicin binding site. In addition, we show that TRPV1 is a locus for cross-sensitization between AITC and acidosis in nociceptive neurons. Furthermore, we show that residue F660, which is known to determine the stimulation by low pH in human TRPV1, is also essential for the cross-sensitization of the effects of AITC and low pH. Taken together, these findings demonstrate that not all reactive electrophiles stimulate TRPV1 via cysteine modification and help understanding the molecular bases underlying the surprisingly large role of this channel as mediator of the algesic properties of AITC.

Determination of Novel Strategies for Hastening Corneal Wound Healing and Reducing Tissue Inflammation

DTIC Science & Technology

2011-10-01

blocking buffer, 5% fat -free milk in 0.1% Tris-buffered solution/Tween-20, for 1 hour at room temperature and then probed overnight at 5°C with...and blotting onto Immun-Blot PVDF membrane (Bio-Rad, Hercules, CA). Membranes were blocked with blocking buffer, 5% fat -free milk in 1x PBS buffer...distribution unlimited 13. SUPPLEMENTARY NOTES The aim of this study is to uncover novel transient receptor potential protein vanilloid-1 (TRPV1

Cannabinoid Receptor Type 1 Agonist ACEA Protects Neurons from Death and Attenuates Endoplasmic Reticulum Stress-Related Apoptotic Pathway Signaling.

PubMed

Vrechi, Talita A; Crunfli, Fernanda; Costa, Andressa P; Torrão, Andréa S

2018-05-01

Neurodegeneration is the result of progressive destruction of neurons in the central nervous system, with unknown causes and pathological mechanisms not yet fully elucidated. Several factors contribute to neurodegenerative processes, including neuroinflammation, accumulation of neurotoxic factors, and misfolded proteins in the lumen of the endoplasmic reticulum (ER). Endocannabinoid signaling has been pointed out as an important modulatory system in several neurodegeneration-related processes, inhibiting the inflammatory response and increasing neuronal survival. Thus, we investigated the presumptive protective effect of the selective cannabinoid type 1 (CB1) receptor agonist arachidonyl-2'-chloroethylamide (ACEA) against inflammatory (lipopolysaccharide, LPS) and ER stress (tunicamycin) stimuli in an in vitro neuronal model (Neuro-2a neuroblastoma cells). Cell viability analysis revealed that ACEA was able to protect against cell death induced by LPS and tunicamycin. This neuroprotective effect occurs via the CB1 receptor in the inflammation process and via the transient receptor potential of vanilloid type-1 (TRPV1) channel in ER stress. Furthermore, the immunoblotting analyses indicated that the neuroprotective effect of ACEA seems to involve the modulation of eukaryotic initiation factor 2 (eIF2α), transcription factor C/EBP homologous protein (CHOP), and caspase 12, as well as the survival/death p44/42 MAPK, ERK1/2-related signaling pathways. Together, these data suggest that the endocannabinoid system is a potential therapeutic target in neurodegenerative processes, especially in ER-related neurodegenerative diseases.

Painful Pathways Induced by Toll-like Receptor Stimulation of Dorsal Root Ganglion Neurons

PubMed Central

Qi, Jia; Buzas, Krisztina; Fan, Huiting; Cohen, Jeffrey I.; Wang, Kening; Mont, Erik; Klinman, Dennis; Oppenheim, Joost J.; Howard, O.M. Zack

2011-01-01

We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that toll-like receptors 3/7/9 (TLRs) are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP10), interleukin-1alpha, interleukin-1beta, and prostaglandin E2 (PGE2), which have previously been shown to augment pain. Further, TLR ligands up-regulated the expression of a nociceptive receptor transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1 expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive ODN, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain. PMID:21515789

Divalent cations potentiate TRPV1 channel by lowering the heat activation threshold

PubMed Central

Cao, Xu; Ma, Linlin; Yang, Fan

2014-01-01

Transient receptor potential vanilloid type 1 (TRPV1) channel responds to a wide spectrum of physical and chemical stimuli. In doing so, it serves as a polymodal cellular sensor for temperature change and pain. Many chemicals are known to strongly potentiate TRPV1 activation, though how this is achieved remains unclear. In this study we investigated the molecular mechanism underlying the gating effects of divalent cations Mg2+ and Ba2+. Using a combination of fluorescence imaging and patch-clamp analysis, we found that these cations potentiate TRPV1 gating by most likely promoting the heat activation process. Mg2+ substantially lowers the activation threshold temperature; as a result, a significant fraction of channels are heat-activated at room temperature. Although Mg2+ also potentiates capsaicin- and voltage-dependent activation, these processes were found either to be not required (in the case of capsaicin) or insufficient (in the case of voltage) to mediate the activating effect. In support of a selective effect on heat activation, Mg2+ and Ba2+ cause a Ca2+-independent desensitization that specifically prevents heat-induced channel activation but does not prevent capsaicin-induced activation. These results can be satisfactorily explained within an allosteric gating framework in which divalent cations strongly promote the heat-dependent conformational change or its coupling to channel activation, which is further coupled to the voltage- and capsaicin-dependent processes. PMID:24344247

Absence of Intracellular Ion Channels TPC1 and TPC2 Leads to Mature-Onset Obesity in Male Mice, Due to Impaired Lipid Availability for Thermogenesis in Brown Adipose Tissue

PubMed Central

Lear, Pamela V.; González-Touceda, David; Porteiro Couto, Begoña; Viaño, Patricia; Guymer, Vanessa; Remzova, Elena; Tunn, Ruth; Chalasani, Annapurna; García-Caballero, Tomás; Hargreaves, Iain P.; Tynan, Patricia W.; Christian, Helen C.; Nogueiras, Rubén

2015-01-01

Intracellular calcium-permeable channels have been implicated in thermogenic function of murine brown and brite/beige adipocytes, respectively transient receptor potential melastin-8 and transient receptor potential vanilloid-4. Because the endo-lysosomal two-pore channels (TPCs) have also been ascribed with metabolic functionality, we studied the effect of simultaneously knocking out TPC1 and TPC2 on body composition and energy balance in male mice fed a chow diet. Compared with wild-type mice, TPC1 and TPC2 double knockout (Tpcn1/2−/−) animals had a higher respiratory quotient and became obese between 6 and 9 months of age. Although food intake was unaltered, interscapular brown adipose tissue (BAT) maximal temperature and lean-mass adjusted oxygen consumption were lower in Tpcn1/2−/− than in wild type mice. Phosphorylated hormone-sensitive lipase expression, lipid density and expression of β-adrenergic receptors were also lower in Tpcn1/2−/− BAT, whereas mitochondrial respiratory chain function and uncoupling protein-1 expression remained intact. We conclude that Tpcn1/2−/− mice show mature-onset obesity due to reduced lipid availability and use, and a defect in β-adrenergic receptor signaling, leading to impaired thermogenic activity, in BAT. PMID:25545384

AKAP150-mediated TRPV1 sensitization is disrupted by calcium/calmodulin

PubMed Central

2011-01-01

Background The transient receptor potential vanilloid type1 (TRPV1) is expressed in nociceptive sensory neurons and is sensitive to phosphorylation. A-Kinase Anchoring Protein 79/150 (AKAP150) mediates phosphorylation of TRPV1 by Protein Kinases A and C, modulating channel activity. However, few studies have focused on the regulatory mechanisms that control AKAP150 association with TRPV1. In the present study, we identify a role for calcium/calmodulin in controlling AKAP150 association with, and sensitization of, TRPV1. Results In trigeminal neurons, intracellular accumulation of calcium reduced AKAP150 association with TRPV1 in a manner sensitive to calmodulin antagonism. This was also observed in transfected Chinese hamster ovary (CHO) cells, providing a model for conducting molecular analysis of the association. In CHO cells, the deletion of the C-terminal calmodulin-binding site of TRPV1 resulted in greater association with AKAP150, and increased channel activity. Furthermore, the co-expression of wild-type calmodulin in CHOs significantly reduced TRPV1 association with AKAP150, as evidenced by total internal reflective fluorescence-fluorescence resonance energy transfer (TIRF-FRET) analysis and electrophysiology. Finally, dominant-negative calmodulin co-expression increased TRPV1 association with AKAP150 and increased basal and PKA-sensitized channel activity. Conclusions the results from these studies indicate that calcium/calmodulin interferes with the association of AKAP150 with TRPV1, potentially extending resensitization of the channel. PMID:21569553

Qiliqiangxin Rescues Mouse Cardiac Function by Regulating AGTR1/TRPV1-Mediated Autophagy in STZ-Induced Diabetes Mellitus.

PubMed

Tong, Jing; Lai, Yan; Yao, Yi-An; Wang, Xue-Jun; Shi, Yu-Shuang; Hou, Han-Jin; Gu, Jian-Yun; Chen, Fei; Liu, Xue-Bo

2018-06-19

To explore the potential role of qiliqiangxin (QLQX) A traditional Chinese medicine and the involvement of angiotensin II receptor type 1 (AGTR1) and transient receptor potential vanilloid 1 (TRPV1) in diabetic mouse cardiac function. Intragastric QLQX was administered for 5 weeks after streptozotocin (STZ) treatment. Additionally, Intraperitoneal injections of angiotensin II (Ang II) or intragastric losartan (Los) were administered to assess the activities of AGTR1 and TRPV1. Two-dimensional echocardiography and tissue histopathology were used to assess cardiac function Western blot was used to detect the autophagic biomarkers Such as light chain 3 P62 and lysosomal-associated membrane protein 2 And transmission electron microscopy was used to count the number of autophagosomes. Decreased expression of TRPV1 and autophagic hallmarks and reduced numbers of autophagolysosomes as well as increased expression of angiotensin converting enzyme 1 and AGTR1 were observed in diabetic hearts. Blocking AGTR1 with Los mimicked the QLQX-mediated improvements in cardiac function Alleviated myocardial fibrosis and enabled autophagy Whereas Ang II abolished the beneficial effects of QLQX in wild type diabetic mice but not in TRPV1-/- diabetic mice. QLQX may improve diabetic cardiac function by regulating AGTR1/ TRPV1-mediated autophagy in STZ-induced diabetic mice. © 2018 The Author(s). Published by S. Karger AG, Basel.

AKAP150-mediated TRPV1 sensitization is disrupted by calcium/calmodulin.

PubMed

Chaudhury, Sraboni; Bal, Manjot; Belugin, Sergei; Shapiro, Mark S; Jeske, Nathaniel A

2011-05-14

The transient receptor potential vanilloid type1 (TRPV1) is expressed in nociceptive sensory neurons and is sensitive to phosphorylation. A-Kinase Anchoring Protein 79/150 (AKAP150) mediates phosphorylation of TRPV1 by Protein Kinases A and C, modulating channel activity. However, few studies have focused on the regulatory mechanisms that control AKAP150 association with TRPV1. In the present study, we identify a role for calcium/calmodulin in controlling AKAP150 association with, and sensitization of, TRPV1. In trigeminal neurons, intracellular accumulation of calcium reduced AKAP150 association with TRPV1 in a manner sensitive to calmodulin antagonism. This was also observed in transfected Chinese hamster ovary (CHO) cells, providing a model for conducting molecular analysis of the association. In CHO cells, the deletion of the C-terminal calmodulin-binding site of TRPV1 resulted in greater association with AKAP150, and increased channel activity. Furthermore, the co-expression of wild-type calmodulin in CHOs significantly reduced TRPV1 association with AKAP150, as evidenced by total internal reflective fluorescence-fluorescence resonance energy transfer (TIRF-FRET) analysis and electrophysiology. Finally, dominant-negative calmodulin co-expression increased TRPV1 association with AKAP150 and increased basal and PKA-sensitized channel activity. the results from these studies indicate that calcium/calmodulin interferes with the association of AKAP150 with TRPV1, potentially extending resensitization of the channel.

Effect of chirality and lipophilicity in the functional activity of evodiamine and its analogues at TRPV1 channels.

PubMed

De Petrocellis, Luciano; Schiano Moriello, Aniello; Fontana, Gabriele; Sacchetti, Alessandro; Passarella, Daniele; Appendino, Giovanni; Di Marzo, Vincenzo

2014-05-01

Evodiamine, a racemic quinazolinocarboline alkaloid isolated from the traditional Chinese medicine Evodiae fructus, has been reported to act as an agonist of the transient receptor potential vanilloid type-1 (TRPV1) cation channel both in vitro and in vivo. Evodiamine is structurally different from all known TRPV1 activators, and has significant clinical potential as a thermogenic agent. Nevertheless, the molecular bases for its actions are still poorly understood. To investigate the structure-activity relationships of evodiamine, the natural racemate was resolved, and a series of 23 synthetic analogues was prepared, using as the end point the intracellular Ca(2+) elevation in HEK-293 cells stably overexpressing either the human or the rat recombinant TRPV1. S-(+) evodiamine was more efficacious and potent than R-(-) evodiamine, and a new potent lead (Evo30) was identified, more potent than the reference TRPV1 agonist, capsaicin. In general, potency and efficacy correlated with the lipophilicity of the analogues. Like other TRPV1 agonists, several synthetic analogues could efficiently desensitize TRPV1 to activation by capsaicin. Evodiamine qualifies as structurally unique lead structure to develop new potent TRPV1 agonists/desensitizers. © 2013 The British Pharmacological Society.

Ca2+ and calpain mediate capsaicin-induced ablation of axonal terminals expressing transient receptor potential vanilloid 1.

PubMed

Wang, Sheng; Wang, Sen; Asgar, Jamila; Joseph, John; Ro, Jin Y; Wei, Feng; Campbell, James N; Chung, Man-Kyo

2017-05-19

Capsaicin is an ingredient in spicy peppers that produces burning pain by activating transient receptor potential vanilloid 1 (TRPV1), a Ca 2+ -permeable ion channel in nociceptors. Capsaicin has also been used as an analgesic, and its topical administration is approved for the treatment of certain pain conditions. The mechanisms underlying capsaicin-induced analgesia likely involve reversible ablation of nociceptor terminals. However, the mechanisms underlying these effects are not well understood. To visualize TRPV1-lineage axons, a genetically engineered mouse model was used in which a fluorophore is expressed under the TRPV1 promoter. Using a combination of these TRPV1-lineage reporter mice and primary afferent cultures, we monitored capsaicin-induced effects on afferent terminals in real time. We found that Ca 2+ influx through TRPV1 is necessary for capsaicin-induced ablation of nociceptive terminals. Although capsaicin-induced mitochondrial Ca 2+ uptake was TRPV1-dependent, dissipation of the mitochondrial membrane potential, inhibition of the mitochondrial transition permeability pore, and scavengers of reactive oxygen species did not attenuate capsaicin-induced ablation. In contrast, MDL28170, an inhibitor of the Ca 2+ -dependent protease calpain, diminished ablation. Furthermore, overexpression of calpastatin, an endogenous inhibitor of calpain, or knockdown of calpain 2 also decreased ablation. Quantitative assessment of TRPV1-lineage afferents in the epidermis of the hind paws of the reporter mice showed that EGTA and MDL28170 diminished capsaicin-induced ablation. Moreover, MDL28170 prevented capsaicin-induced thermal hypoalgesia. These results suggest that TRPV1/Ca 2+ /calpain-dependent signaling plays a dominant role in capsaicin-induced ablation of nociceptive terminals and further our understanding of the molecular mechanisms underlying the effects of capsaicin on nociceptors. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Interactions between superficial and deep dorsal horn spinal cord neurons in the processing of nociceptive information.

PubMed

Petitjean, Hugues; Rodeau, Jean-Luc; Schlichter, Rémy

2012-12-01

In acute rat spinal cord slices, the application of capsaicin (5 μm, 90 s), an agonist of transient receptor potential vanilloid 1 receptors expressed by a subset of nociceptors that project to laminae I-II of the spinal cord dorsal horn, induced an increase in the frequency of spontaneous excitatory and spontaneous inhibitory postsynaptic currents in about half of the neurons in laminae II, III-IV and V. In the presence of tetrodotoxin, which blocks action potential generation and polysynaptic transmission, capsaicin increased the frequency of miniature excitatory postsynaptic currents in only 30% of lamina II neurons and had no effect on the frequency of miniature excitatory postsynaptic currents in laminae III-V or on the frequency of miniature inhibitory postsynaptic currents in laminae II-V. When the communication between lamina V and more superficial laminae was interrupted by performing a mechanical section between laminae IV and V, capsaicin induced an increase in spontaneous excitatory postsynaptic current frequency in laminae II-IV and an increase in spontaneous inhibitory postsynaptic current frequency in lamina II that were similar to those observed in intact slices. However, in laminae III-IV of transected slices, the increase in spontaneous inhibitory postsynaptic current frequency was virtually abolished. Our results indicate that nociceptive information conveyed by transient receptor potential vanilloid 1-expressing nociceptors is transmitted from lamina II to deeper laminae essentially by an excitatory pathway and that deep laminae exert a 'feedback' control over neurons in laminae III-IV by increasing inhibitory synaptic transmission in these laminae. Moreover, we provide evidence that laminae III-IV might play an important role in the processing of nociceptive information in the dorsal horn. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Targeting fatty acid amide hydrolase and transient receptor potential vanilloid-1 simultaneously to modulate colonic motility and visceral sensation in the mouse: A pharmacological intervention with N-arachidonoyl-serotonin (AA-5-HT).

PubMed

Bashashati, M; Fichna, J; Piscitelli, F; Capasso, R; Izzo, A A; Sibaev, A; Timmermans, J-P; Cenac, N; Vergnolle, N; Di Marzo, V; Storr, M

2017-12-01

Endocannabinoid anandamide (AEA) inhibits intestinal motility and visceral pain, but it may also be proalgesic through transient receptor potential vanilloid-1 (TRPV1). AEA is degraded by fatty acid amide hydrolase (FAAH). This study explored whether dual inhibition of FAAH and TRPV1 reduces diarrhea and abdominal pain. Immunostaining was performed on myenteric plexus of the mouse colon. The effects of the dual FAAH/TRPV1 inhibitor AA-5-HT on electrically induced contractility, excitatory junction potential (EJP) and fast (f) and slow (s) inhibitory junction potentials (IJP) in the mouse colon, colonic propulsion and visceromotor response (VMR) to rectal distension were studied. The colonic levels of endocannabinoids and fatty acid amides were measured. CB1-positive neurons exhibited TRPV1; only some TRPV1 positive neurons did not express CB1. CB1 and FAAH did not colocalize. AA-5-HT (100 nM-10 μM) decreased colonic contractility by ~60%; this effect was abolished by TRPV1 antagonist 5'-IRTX, but not by CB1 antagonist, SR141716. AA-5-HT (1 μM-10 μM) inhibited EJP by ~30% and IJPs by ~50%. The effects of AA-5-HT on junction potentials were reversed by SR141716 and 5`-IRTX. AA-5-HT (20 mg/kg; i.p.) inhibited colonic propulsion by ~30%; SR141716 but not 5`-IRTX reversed this effect. AA-5-HT decreased VMR by ~50%-60%; these effects were not blocked by SR141716 or 5`-IRTX. AA-5-HT increased AEA in the colon. The effects of AA-5-HT on visceral sensation and colonic motility are differentially mediated by CB1, TRPV1 and non-CB1/TRPV1 mechanisms, possibly reflecting the distinct neuromodulatory roles of endocannabinoid and endovanilloid FAAH substrates in the mouse intestine. © 2017 John Wiley & Sons Ltd.

Epidermal Growth Factor Receptor Transactivation by the Cannabinoid Receptor (CB1) and Transient Receptor Potential Vanilloid 1 (TRPV1) Induces Differential Responses in Corneal Epithelial Cells

DTIC Science & Technology

2010-01-01

induced Ca2þ signaling as well as phospholipase D (PLD)-mediated phosphatidic acid formation (Islam and Akhtar, 2000; Kang et al., 2000, 2001; Mazie et...Epithelial cell motility is triggered by activation of the EGF receptor through phosphatidic acid signaling. J. Cell Sci. 119, 1645e1654. McIntosh, B.T...buffer. Cell lysates were centrifuged and supernatants were collected for measuring proteins with a bichinchoninic acid assay (BCA) protein assay kit

TRPV1: A Target for Rational Drug Design

PubMed Central

Carnevale, Vincenzo; Rohacs, Tibor

2016-01-01

Transient Receptor Potential Vanilloid 1 (TRPV1) is a non-selective, Ca2+ permeable cation channel activated by noxious heat, and chemical ligands, such as capsaicin and resiniferatoxin (RTX). Many compounds have been developed that either activate or inhibit TRPV1, but none of them are in routine clinical practice. This review will discuss the rationale for antagonists and agonists of TRPV1 for pain relief and other conditions, and strategies to develop new, better drugs to target this ion channel, using the newly available high-resolution structures. PMID:27563913

Transient receptor potential channel superfamily: Role in lower urinary tract function.

PubMed

Ogawa, Teruyuki; Imamura, Tetsuya; Nakazawa, Masaki; Hiragata, Shiro; Nagai, Takashi; Minagawa, Tomonori; Yokoyama, Hitoshi; Ishikawa, Masakuni; Domen, Takahisa; Ishizuka, Osamu

2015-11-01

Lower urinary tract symptoms associated with neurogenic bladder and overactive bladder syndrome are mediated in part by members of the transient receptor potential channel superfamily. The best studied member of this superfamily is the vanilloid receptor. Other transient receptor potential channels, such as the melastatin receptor and the ankyrin receptor, are also active in the pathogenesis of lower urinary tract dysfunction. However, the detailed mechanisms by which the transient receptor potential channels contribute to lower urinary tract symptoms are still not clear, and the therapeutic benefits of modulating transient receptor potential channel activity have not been proved in the clinical setting. In the present review, to better understand the pathophysiology and therapeutic potential for lower urinary tract symptoms, we summarize the presence and role of different members of the transient receptor potential channel superfamily in the lower urinary tract. © 2015 The Japanese Urological Association.

Kunitz-Type Peptide HCRG21 from the Sea Anemone Heteractis crispa Is a Full Antagonist of the TRPV1 Receptor

PubMed Central

Monastyrnaya, Margarita; Peigneur, Steve; Zelepuga, Elena; Sintsova, Oksana; Gladkikh, Irina; Leychenko, Elena; Isaeva, Marina; Tytgat, Jan; Kozlovskaya, Emma

2016-01-01

Sea anemone venoms comprise multifarious peptides modulating biological targets such as ion channels or receptors. The sequence of a new Kunitz-type peptide, HCRG21, belonging to the Heteractis crispa RG (HCRG) peptide subfamily was deduced on the basis of the gene sequence obtained from the Heteractis crispa cDNA. HCRG21 shares high structural homology with Kunitz-type peptides APHC1–APHC3 from H. crispa, and clusters with the peptides from so named “analgesic cluster” of the HCGS peptide subfamily but forms a separate branch on the NJ-phylogenetic tree. Three unique point substitutions at the N-terminus of the molecule, Arg1, Gly2, and Ser5, distinguish HCRG21 from other peptides of this cluster. The trypsin inhibitory activity of recombinant HCRG21 (rHCRG21) was comparable with the activity of peptides from the same cluster. Inhibition constants for trypsin and α-chymotrypsin were 1.0 × 10−7 and 7.0 × 10−7 M, respectively. Electrophysiological experiments revealed that rHCRG21 inhibits 95% of the capsaicin-induced current through transient receptor potential family member vanilloid 1 (TRPV1) and has a half-maximal inhibitory concentration of 6.9 ± 0.4 μM. Moreover, rHCRG21 is the first full peptide TRPV1 inhibitor, although displaying lower affinity for its receptor in comparison with other known ligands. Macromolecular docking and full atom Molecular Dynamics (MD) simulations of the rHCRG21–TRPV1 complex allow hypothesizing the existence of two feasible, intra- and extracellular, molecular mechanisms of blocking. These data provide valuable insights in the structural and functional relationships and pharmacological potential of bifunctional Kunitz-type peptides. PMID:27983679

Kunitz-Type Peptide HCRG21 from the Sea Anemone Heteractis crispa Is a Full Antagonist of the TRPV1 Receptor.

PubMed

Monastyrnaya, Margarita; Peigneur, Steve; Zelepuga, Elena; Sintsova, Oksana; Gladkikh, Irina; Leychenko, Elena; Isaeva, Marina; Tytgat, Jan; Kozlovskaya, Emma

2016-12-15

Sea anemone venoms comprise multifarious peptides modulating biological targets such as ion channels or receptors. The sequence of a new Kunitz-type peptide, HCRG21, belonging to the Heteractis crispa RG (HCRG) peptide subfamily was deduced on the basis of the gene sequence obtained from the Heteractis crispa cDNA. HCRG21 shares high structural homology with Kunitz-type peptides APHC1-APHC3 from H. crispa , and clusters with the peptides from so named "analgesic cluster" of the HCGS peptide subfamily but forms a separate branch on the NJ-phylogenetic tree. Three unique point substitutions at the N-terminus of the molecule, Arg1, Gly2, and Ser5, distinguish HCRG21 from other peptides of this cluster. The trypsin inhibitory activity of recombinant HCRG21 (rHCRG21) was comparable with the activity of peptides from the same cluster. Inhibition constants for trypsin and α-chymotrypsin were 1.0 × 10 -7 and 7.0 × 10 -7 M, respectively. Electrophysiological experiments revealed that rHCRG21 inhibits 95% of the capsaicin-induced current through transient receptor potential family member vanilloid 1 (TRPV1) and has a half-maximal inhibitory concentration of 6.9 ± 0.4 μM. Moreover, rHCRG21 is the first full peptide TRPV1 inhibitor, although displaying lower affinity for its receptor in comparison with other known ligands. Macromolecular docking and full atom Molecular Dynamics (MD) simulations of the rHCRG21-TRPV1 complex allow hypothesizing the existence of two feasible, intra- and extracellular, molecular mechanisms of blocking. These data provide valuable insights in the structural and functional relationships and pharmacological potential of bifunctional Kunitz-type peptides.

Sensing of blood pressure increase by transient receptor potential vanilloid 1 receptors on baroreceptors.

PubMed

Sun, Hao; Li, De-Pei; Chen, Shao-Rui; Hittelman, Walter N; Pan, Hui-Lin

2009-12-01

The arterial baroreceptor is critically involved in the autonomic regulation of homoeostasis. The transient receptor potential vanilloid 1 (TRPV1) receptor is expressed on both somatic and visceral sensory neurons. Here, we examined the TRPV1 innervation of baroreceptive pathways and its functional significance in the baroreflex. Resiniferatoxin (RTX), an ultrapotent analog of capsaicin, was used to ablate TRPV1-expressing afferent neurons and fibers in adult rats. Immunofluorescence labeling revealed that TRPV1 immunoreactivity was present on nerve fibers and terminals in the adventitia of the ascending aorta and aortic arch, the nodose ganglion neurons, and afferent fibers in the solitary tract of the brainstem. RTX treatment eliminated TRPV1 immunoreactivities in the aorta, nodose ganglion, and solitary tract. Renal sympathetic nerve activity, blood pressure, and heart rate were recorded in anesthetized rats. The baroreflex was triggered by lowering and raising blood pressure through intravenous infusion of sodium nitroprusside and phenylephrine, respectively. Inhibition of sympathetic nerve activity and heart rate by the phenylephrine-induced increase in blood pressure was largely impaired in RTX-treated rats. The maximum gain of the baroreflex function was significantly lower in RTX-treated than vehicle-treated rats. Furthermore, blocking of TRPV1 receptors significantly blunted the baroreflex and decreased the maximum gain of baroreflex function in the high blood pressure range. Our findings provide important new information that TRPV1 is expressed along the entire baroreceptive afferent pathway. TRPV1 receptors expressed on baroreceptive nerve endings can function as mechanoreceptors to detect the increase in blood pressure and maintain the homoeostasis.

Sensing of Blood Pressure Increase by Transient Receptor Potential Vanilloid 1 Receptors on Baroreceptors

PubMed Central

Sun, Hao; Li, De-Pei; Chen, Shao-Rui; Hittelman, Walter N.

2009-01-01

The arterial baroreceptor is critically involved in the autonomic regulation of homoeostasis. The transient receptor potential vanilloid 1 (TRPV1) receptor is expressed on both somatic and visceral sensory neurons. Here, we examined the TRPV1 innervation of baroreceptive pathways and its functional significance in the baroreflex. Resiniferatoxin (RTX), an ultrapotent analog of capsaicin, was used to ablate TRPV1-expressing afferent neurons and fibers in adult rats. Immunofluorescence labeling revealed that TRPV1 immunoreactivity was present on nerve fibers and terminals in the adventitia of the ascending aorta and aortic arch, the nodose ganglion neurons, and afferent fibers in the solitary tract of the brainstem. RTX treatment eliminated TRPV1 immunoreactivities in the aorta, nodose ganglion, and solitary tract. Renal sympathetic nerve activity, blood pressure, and heart rate were recorded in anesthetized rats. The baroreflex was triggered by lowering and raising blood pressure through intravenous infusion of sodium nitroprusside and phenylephrine, respectively. Inhibition of sympathetic nerve activity and heart rate by the phenylephrine-induced increase in blood pressure was largely impaired in RTX-treated rats. The maximum gain of the baroreflex function was significantly lower in RTX-treated than vehicle-treated rats. Furthermore, blocking of TRPV1 receptors significantly blunted the baroreflex and decreased the maximum gain of baroreflex function in the high blood pressure range. Our findings provide important new information that TRPV1 is expressed along the entire baroreceptive afferent pathway. TRPV1 receptors expressed on baroreceptive nerve endings can function as mechanoreceptors to detect the increase in blood pressure and maintain the homoeostasis. PMID:19726694

Efficient modulation of γ-aminobutyric acid type A receptors by piperine derivatives.

PubMed

Schöffmann, Angela; Wimmer, Laurin; Goldmann, Daria; Khom, Sophia; Hintersteiner, Juliane; Baburin, Igor; Schwarz, Thomas; Hintersteininger, Michael; Pakfeifer, Peter; Oufir, Mouhssin; Hamburger, Matthias; Erker, Thomas; Ecker, Gerhard F; Mihovilovic, Marko D; Hering, Steffen

2014-07-10

Piperine activates TRPV1 (transient receptor potential vanilloid type 1 receptor) receptors and modulates γ-aminobutyric acid type A receptors (GABAAR). We have synthesized a library of 76 piperine analogues and analyzed their effects on GABAAR by means of a two-microelectrode voltage-clamp technique. GABAAR were expressed in Xenopus laevis oocytes. Structure-activity relationships (SARs) were established to identify structural elements essential for efficiency and potency. Efficiency of piperine derivatives was significantly increased by exchanging the piperidine moiety with either N,N-dipropyl, N,N-diisopropyl, N,N-dibutyl, p-methylpiperidine, or N,N-bis(trifluoroethyl) groups. Potency was enhanced by replacing the piperidine moiety by N,N-dibutyl, N,N-diisobutyl, or N,N-bistrifluoroethyl groups. Linker modifications did not substantially enhance the effect on GABAAR. Compound 23 [(2E,4E)-5-(1,3-benzodioxol-5-yl)-N,N-dipropyl-2,4-pentadienamide] induced the strongest modulation of GABAA (maximal GABA-induced chloride current modulation (IGABA-max = 1673% ± 146%, EC50 = 51.7 ± 9.5 μM), while 25 [(2E,4E)-5-(1,3-benzodioxol-5-yl)-N,N-dibutyl-2,4-pentadienamide] displayed the highest potency (EC50 = 13.8 ± 1.8 μM, IGABA-max = 760% ± 47%). Compound 23 induced significantly stronger anxiolysis in mice than piperine and thus may serve as a starting point for developing novel GABAAR modulators.

Efficient Modulation of γ-Aminobutyric Acid Type A Receptors by Piperine Derivatives

PubMed Central

2014-01-01

Piperine activates TRPV1 (transient receptor potential vanilloid type 1 receptor) receptors and modulates γ-aminobutyric acid type A receptors (GABAAR). We have synthesized a library of 76 piperine analogues and analyzed their effects on GABAAR by means of a two-microelectrode voltage-clamp technique. GABAAR were expressed in Xenopus laevis oocytes. Structure–activity relationships (SARs) were established to identify structural elements essential for efficiency and potency. Efficiency of piperine derivatives was significantly increased by exchanging the piperidine moiety with either N,N-dipropyl, N,N-diisopropyl, N,N-dibutyl, p-methylpiperidine, or N,N-bis(trifluoroethyl) groups. Potency was enhanced by replacing the piperidine moiety by N,N-dibutyl, N,N-diisobutyl, or N,N-bistrifluoroethyl groups. Linker modifications did not substantially enhance the effect on GABAAR. Compound 23 [(2E,4E)-5-(1,3-benzodioxol-5-yl)-N,N-dipropyl-2,4-pentadienamide] induced the strongest modulation of GABAA (maximal GABA-induced chloride current modulation (IGABA-max = 1673% ± 146%, EC50 = 51.7 ± 9.5 μM), while 25 [(2E,4E)-5-(1,3-benzodioxol-5-yl)-N,N-dibutyl-2,4-pentadienamide] displayed the highest potency (EC50 = 13.8 ± 1.8 μM, IGABA-max = 760% ± 47%). Compound 23 induced significantly stronger anxiolysis in mice than piperine and thus may serve as a starting point for developing novel GABAAR modulators. PMID:24905252

Inhibition by TRPA1 agonists of compound action potentials in the frog sciatic nerve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsushita, Akitomo; Ohtsubo, Sena; Fujita, Tsugumi

Highlights: •TRPA1 agonists inhibited compound action potentials in frog sciatic nerves. •This inhibition was not mediated by TRPA1 channels. •This efficacy was comparable to those of lidocaine and cocaine. •We found for the first time an ability of TRPA1 agonists to inhibit nerve conduction. -- Abstract: Although TRPV1 and TRPM8 agonists (vanilloid capsaicin and menthol, respectively) at high concentrations inhibit action potential conduction, it remains to be unknown whether TRPA1 agonists have a similar action. The present study examined the actions of TRPA1 agonists, cinnamaldehyde (CA) and allyl isothiocyanate (AITC), which differ in chemical structure from each other, on compoundmore » action potentials (CAPs) recorded from the frog sciatic nerve by using the air-gap method. CA and AITC concentration-dependently reduced the peak amplitude of the CAP with the IC{sub 50} values of 1.2 and 1.5 mM, respectively; these activities were resistant to a non-selective TRP antagonist ruthenium red or a selective TRPA1 antagonist HC-030031. The CA and AITC actions were distinct in property; the latter but not former action was delayed in onset and partially reversible, and CA but not AITC increased thresholds to elicit CAPs. A CAP inhibition was seen by hydroxy-α-sanshool (by 60% at 0.05 mM), which activates both TRPA1 and TRPV1 channels, a non-vanilloid TRPV1 agonist piperine (by 20% at 0.07 mM) and tetrahydrolavandulol (where the six-membered ring of menthol is opened; IC{sub 50} = 0.38 mM). It is suggested that TRPA1 agonists as well as TRPV1 and TRPM8 agonists have an ability to inhibit nerve conduction without TRP activation, although their agonists are quite different in chemical structure from each other.« less

Randomised clinical trial: the efficacy of a transient receptor potential vanilloid 1 antagonist AZD1386 in human oesophageal pain.

PubMed

Krarup, A L; Ny, L; Astrand, M; Bajor, A; Hvid-Jensen, F; Hansen, M B; Simrén, M; Funch-Jensen, P; Drewes, A M

2011-05-01

Many patients with gastro-oesophageal reflux disease (GERD) are hypersensitive to heat and acid and may respond insufficiently to standard treatment. Antagonists of the heat and acid receptor 'transient receptor potential vanilloid 1'(TRPV1) are a potential drug class for GERD treatment. To investigate the effect of a TRPV1 antagonist (AZD1386) on experimentally induced oesophageal pain. Twenty-two healthy men (20-31 years) participated in this randomised, placebo-controlled, double-blinded, crossover study examining the effects of a single-dose oral AZD1386 (30 and 95 mg). Subjects were block-randomised. On treatment days, participants were stimulated with painful heat, distension, electrical current and acid in the oesophagus. Heat and pressure pain on the forearm were somatic control stimuli. intention-to-treat. A total of 21 participants completed the protocol and 1 voluntarily discontinued. In the oesophagus, both 30 and 95 mg of AZD1386 increased pain thresholds to heat stimuli 23% [95% confidence interval (CI): 10-38%] and 28%, respectively (CI: 14-43%). The skin heat tolerance was increased 2.1 °C (CI: 1.1-3.2 °C) after 30 mg AZD1386 and 4.0 °C (CI: 3.0-5.0 °C) after 95 mg. Heat analgesia persisted for 2.5 h. Pain thresholds to the other stimuli were unaffected by AZD1386. 50% reported 'feeling cold' and body temperature increased in all subjects exposed to 30 and 95 mg AZD1386 (mean increase 0.4±0.3 °C and 0.7±0.3 °C, respectively, P<0.05). AZD1386 increased oesophageal and skin heat pain thresholds and had a safe adverse-event profile. This drug class may have a potential for treatment of GERD. © 2011 Blackwell Publishing Ltd.

TRPV1, TRPA1, and TRPM8 channels in inflammation, energy redirection, and water retention: role in chronic inflammatory diseases with an evolutionary perspective.

PubMed

Straub, Rainer H

2014-09-01

Chronic inflammatory diseases are accompanied by a systemic response of the body, necessary to redirect energy-rich fuels to the activated immune system and to induce volume expansion. The systemic response is switched on by two major pathways: (a) circulating cytokines enter the brain, and (b) signals via sensory nerve fibers are transmitted to the brain. Concerning item b, sensory nerve terminals are equipped with a multitude of receptors that sense temperature, inflammation, osmolality, and pain. Thus, they can be important to inform the brain about peripheral inflammation. Central to these sensory modalities are transient receptor potential channels (TRP channels) on sensory nerve endings. For example, TRP vanilloid 1 (TRPV1) can be activated by heat, inflammatory factors (e.g., protons, bradykinin, anandamide), hyperosmolality, pungent irritants, and others. TRP channels are multimodal switches that transmit peripheral signals to the brain, thereby inducing a systemic response. It is demonstrated how and why these TRP channels (TRPV1, TRP ankyrin type 1 (TRPA1), and TRP melastatin type 8 (TRPM8)) are important to start up a systemic response of energy expenditure, energy allocation, and water retention and how this is linked to a continuously activated immune system in chronic inflammatory diseases.

GABAA receptor activity modulating piperine analogs: In vitro metabolic stability, metabolite identification, CYP450 reaction phenotyping, and protein binding.

PubMed

Zabela, Volha; Hettich, Timm; Schlotterbeck, Götz; Wimmer, Laurin; Mihovilovic, Marko D; Guillet, Fabrice; Bouaita, Belkacem; Shevchenko, Bénédicte; Hamburger, Matthias; Oufir, Mouhssin

2018-01-01

In a screening of natural products for allosteric modulators of GABA A receptors (γ-aminobutyric acid type A receptor), piperine was identified as a compound targeting a benzodiazepine-independent binding site. Given that piperine is also an activator of TRPV1 (transient receptor potential vanilloid type 1) receptors involved in pain signaling and thermoregulation, a series of piperine analogs were prepared in several cycles of structural optimization, with the aim of separating GABA A and TRPV1 activating properties. We here investigated the metabolism of piperine and selected analogs in view of further cycles of lead optimization. Metabolic stability of the compounds was evaluated by incubation with pooled human liver microsomes, and metabolites were analyzed by UHPLC-Q-TOF-MS. CYP450 isoenzymes involved in metabolism of compounds were identified by reaction phenotyping with Silensomes™. Unbound fraction in whole blood was determined by rapid equilibrium dialysis. Piperine was the metabolically most stable compound. Aliphatic hydroxylation, and N- and O-dealkylation were the major routes of oxidative metabolism. Piperine was exclusively metabolized by CYP1A2, whereas CYP2C9 contributed significantly in the oxidative metabolism of all analogs. Extensive binding to blood constituents was observed for all compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

An Aversive Response to Osmotic Upshift in Caenorhabditis elegans.

PubMed

Yu, Jingyi; Yang, Wenxing; Liu, He; Hao, Yingsong; Zhang, Yun

2017-01-01

Environmental osmolarity presents a common type of sensory stimulus to animals. While behavioral responses to osmotic changes are important for maintaining a stable intracellular osmolarity, the underlying mechanisms are not fully understood. In the natural habitat of Caenorhabditis elegans , changes in environmental osmolarity are commonplace. It is known that the nematode acutely avoids shocks of extremely high osmolarity. Here, we show that C. elegans also generates gradually increased aversion of mild upshifts in environmental osmolarity. Different from an acute avoidance of osmotic shocks that depends on the function of a transient receptor potential vanilloid channel, the slow aversion to osmotic upshifts requires the cGMP-gated sensory channel subunit TAX-2. TAX-2 acts in several sensory neurons that are exposed to body fluid to generate the aversive response through a motor network that underlies navigation. Osmotic upshifts activate the body cavity sensory neuron URX, which is known to induce aversion upon activation. Together, our results characterize the molecular and cellular mechanisms underlying a novel sensorimotor response to osmotic stimuli and reveal that C. elegans engages different behaviors and the underlying mechanisms to regulate responses to extracellular osmolarity.

Control of synaptic function by endocannabinoid-mediated retrograde signaling.

PubMed

Kano, Masanobu

2014-01-01

Since the first reports in 2001, great advances have been made towards the understanding of endocannabinoid-mediated synaptic modulation. Electrophysiological studies have revealed that one of the two major endocannabinoids, 2-arachidonoylglycerol (2-AG), is produced from membrane lipids upon postsynaptic Ca(2+) elevation and/or activation of Gq/11-coupled receptors, and released from postsynaptic neurons. The released 2-AG then acts retrogradely onto presynaptic cannabinoid CB1 receptors and induces suppression of neurotransmitter release either transiently or persistently. These forms of 2-AG-mediated retrograde synaptic modulation are functional throughout the brain. The other major endocannabinoid, anandamide, mediates a certain form of endocannabinoid-mediated long-term depression (LTD). Anandamide also functions as an agonist for transient receptor potential vanilloid receptor type 1 (TRPV1) and mediates endocannabinoid-independent and TRPV1-dependent forms of LTD. It has also been demonstrated that the endocannabinoid system itself is plastic, which can be either up- or down-regulated by experimental or environmental conditions. In this review, I will make an overview of the mechanisms underlying endocannabinoid-mediated synaptic modulation.

Control of synaptic function by endocannabinoid-mediated retrograde signaling

PubMed Central

KANO, Masanobu

2014-01-01

Since the first reports in 2001, great advances have been made towards the understanding of endocannabinoid-mediated synaptic modulation. Electrophysiological studies have revealed that one of the two major endocannabinoids, 2-arachidonoylglycerol (2-AG), is produced from membrane lipids upon postsynaptic Ca2+ elevation and/or activation of Gq/11-coupled receptors, and released from postsynaptic neurons. The released 2-AG then acts retrogradely onto presynaptic cannabinoid CB1 receptors and induces suppression of neurotransmitter release either transiently or persistently. These forms of 2-AG-mediated retrograde synaptic modulation are functional throughout the brain. The other major endocannabinoid, anandamide, mediates a certain form of endocannabinoid-mediated long-term depression (LTD). Anandamide also functions as an agonist for transient receptor potential vanilloid receptor type 1 (TRPV1) and mediates endocannabinoid-independent and TRPV1-dependent forms of LTD. It has also been demonstrated that the endocannabinoid system itself is plastic, which can be either up- or down-regulated by experimental or environmental conditions. In this review, I will make an overview of the mechanisms underlying endocannabinoid-mediated synaptic modulation. PMID:25169670

Capsaicin and N-arachidonoyl-dopamine (NADA) decrease tension by activating both cannabinoid and vanilloid receptors in fast skeletal muscle fibers of the frog.

PubMed

Trujillo, Xóchitl; Ortiz-Mesina, Mónica; Uribe, Tannia; Castro, Elena; Montoya-Pérez, Rocío; Urzúa, Zorayda; Feria-Velasco, Alfredo; Huerta, Miguel

2015-02-01

Previous studies have indicated that vanilloid receptor (VR1) mRNA is expressed in muscle fibers. In this study, we evaluated the functional effects of VR1 activation. We measured caffeine-induced contractions in bundles of the extensor digitorum longus muscle of Rana pipiens. Isometric tension measurements showed that two VR1 agonists, capsaicin (CAP) and N-arachidonoyl-dopamine (NADA), reduced muscle peak tension to 57 ± 4 % and 71 ± 3% of control, respectively. The effect of CAP was partially blocked by a VR1 blocker, capsazepine (CPZ), but the effect of NADA was not changed by CPZ. Because NADA is able to act on cannabinoid receptors, which are also present in muscle fibers, we tested the cannabinoid antagonist AM281. We found that AM281 antagonized both CAP and NADA effects. AM281 alone reduced peak tension to 80 ± 6 % of control. With both antagonists, the CAP effect was completely blocked, and the NADA effect was partially blocked. These results provide pharmacological evidence of the functional presence of the VR1 receptor in fast skeletal muscle fibers of the frog and suggest that capsaicin and NADA reduce tension by activating both cannabinoid and vanilloid receptors.

Characterization of Membrane Patch-Ion Channel Probes for Scanning Ion Conductance Microscopy.

PubMed

Shi, Wenqing; Zeng, Yuhan; Zhu, Cheng; Xiao, Yucheng; Cummins, Theodore R; Hou, Jianghui; Baker, Lane A

2018-05-01

Integration of dual-barrel membrane patch-ion channel probes (MP-ICPs) to scanning ion conductance microscopy (SICM) holds promise of providing a revolutionized approach of spatially resolved chemical sensing. A series of experiments are performed to further the understanding of the system and to answer some fundamental questions, in preparation for future developments of this approach. First, MP-ICPs are constructed that contain different types of ion channels including transient receptor potential vanilloid 1 and large conductance Ca2 + -activated K + channels to establish the generalizability of the methods. Next, the capability of the MP-ICP platforms in single ion channel activity measurements is proved. In addition, the interplay between the SICM barrel and the ICP barrel is studied. For ion channels gated by uncharged ligands, channel activity at the ICP barrel is unaffected by the SICM barrel potential; whereas for ion channels that are gated by charged ligands, enhanced channel activity can be obtained by biasing the SICM barrel at potentials with opposite polarity to the charge of the ligand molecules. Finally, a proof-of-principle experiment is performed and site-specific molecular/ionic flux sensing is demonstrated at single-ion-channel level, which show that the MP-ICP platform can be used to quantify local molecular/ionic concentrations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Triggering of the TRPV2 channel by cannabidiol sensitizes glioblastoma cells to cytotoxic chemotherapeutic agents.

PubMed

Nabissi, Massimo; Morelli, Maria Beatrice; Santoni, Matteo; Santoni, Giorgio

2013-01-01

The aggressive behavior of Glioblastoma multiforme (GBM) is mainly due to high invasiveness and proliferation rate as well as to high resistance to standard chemotherapy. Several chemotherapeutic agents like temozolomide (TMZ), carmustine (BCNU) or doxorubicin (DOXO) have been employed for treatment of GBM, but they display limited efficacy. Therefore, it is important to identify new treatment modalities to improve therapeutic effects and enhance GBM chemosensitivity. Recently, activation of the transient receptor potential vanilloid type 2 (TRPV2) has been found to inhibit human GBM cell proliferation and overcome BCNU resistance of GBM cells. Herein, we evaluated the involvement of cannabidiol (CBD)-induced TRPV2 activation, in the modulation of glioma cell chemosensitivity to TMZ, BCNU and DOXO. We found that CBD increases TRPV2 expression and activity. CBD by triggering TRPV2-dependent Ca(2+) influx increases drug uptake and synergizes with cytotoxic agents to induce apoptosis of glioma cells, whereas no effects were observed in normal human astrocytes. Moreover, as the pore region of transient receptor potential (TRP) channels is critical for ion channel permeation, we demonstrated that deletion of TRPV2 poredomain inhibits CBD-induced Ca(2+) influx, drug uptake and cytotoxic effects. Overall, we demonstrated that co-administration of cytotoxic agents together with the TRPV2 agonist CBD increases drug uptake and parallelly potentiates cytotoxic activity in human glioma cells.

Protecting western redcedar from deer browsing—with a passing reference to TRP channels

PubMed Central

Romanovsky, Andrej A

2015-01-01

This editorial is about tree farming. It proposes to test in an experiment whether co-planting (in the same hole) western redcedar (WRC, Thuja plicata) with Sitka spruce (Picea sitchensis) protects WRC seedlings from wildlife browsing. This sustainable protection method is an alternative to the traditional use of mechanical devices and big-game repellents. Many repellents contain transient receptor potential (TRP) agonists, such as capsaicin, a TRP vanilloid-1 agonist. This editorial also delivers a puzzle: while herbivores avoid capsaicin, why do people living in hot climates consume large quantities of it (in chili peppers)? PMID:27227013

TRPV1 Gene Polymorphisms Are Associated with Type 2 Diabetes by Their Interaction with Fat Consumption in the Korean Genome Epidemiology Study.

PubMed

Park, Sunmin; Zhang, Xin; Lee, Na Ra; Jin, Hyun-Seok

2016-01-01

Different transient receptor potential vanilloid 1 (TRPV1) variants may be differently activated by noxious stimuli. We investigated how TRPV1 variants modulated the prevalence of type 2 diabetes and specific gene-nutrient interactions. Among 8,842 adults aged 40-69 years in the Korean Genome Epidemiology Study, the associations between TRPV1 genotypes and the prevalence of type 2 diabetes as well as their gene-nutrient interactions were investigated after adjusting for the covariates of age, gender, residence area, body mass index, daily energy intake, and total activity. The TRPV1 rs161364 and rs8065080 minor alleles lowered HOMA-IR and the risk of type 2 diabetes after adjusting for covariates. There were gene-nutrient interactions between TRPV1 variants rs161364 and rs8065080 and preference for oily taste, intake of oily foods, and fat intake after adjusting for covariates. Among subjects with the minor alleles of TRPV1 rs161364 and rs8065080, the group with a high preference for oily foods had a lower odds ratio for type 2 diabetes. Consistent with the preference for taste, among subjects with the minor alleles, the group with high fat intake from oily foods also exhibited a lower risk of type 2 diabetes than subjects with the major alleles. People with the minor alleles of the TRPV1 single nucleotide polymorphisms rs161364 and rs8065080 have a lower risk of diabetes with a high-fat diet, but people with the major alleles are at a higher risk of type 2 diabetes when consuming high-fat diets. The majority of people should be careful about a high fat intake. © 2016 S. Karger AG, Basel.

Vanilloid receptor-related osmotically activated channel (VR-OAC), a candidate vertebrate osmoreceptor

PubMed Central

Liedtke, Wolfgang; Choe, Yong; Martí-Renom, Marc A.; Bell, Andrea M.; Denis, Charlotte S.; Šali, Andrej; Hudspeth, A. J.; Friedman, Jeffrey M.; Heller, Stefan

2008-01-01

SUMMARY The detection of osmotic stimuli is essential for all organisms, yet few osmoreceptive proteins are known, none of them in vertebrates. By employing a candidate-gene approach based on genes encoding members of the TRP superfamily of ion channels, we cloned cDNAs encoding the vanilloid receptor-related osmotically activated channel (VR-OAC) from the rat, mouse, human, and chicken. This novel cation-selective channel is gated by exposure to hypotonicity within the physiological range. In the central nevous system, the channel is expressed neurons of the circumventricular organs, neurosensory cells responsive to systemic osmotic pressure. The channel also occurs in other neurosensory cells, including inner-ear hair cells, sensory neurons, and Merkel cells. PMID:11081638

International Union of Basic and Clinical Pharmacology. LXXIX. Cannabinoid Receptors and Their Ligands: Beyond CB1 and CB2

PubMed Central

Howlett, A. C.; Abood, M. E.; Alexander, S. P. H.; Di Marzo, V.; Elphick, M. R.; Greasley, P. J.; Hansen, H. S.; Kunos, G.; Mackie, K.; Mechoulam, R.; Ross, R. A.

2010-01-01

There are at least two types of cannabinoid receptors (CB1 and CB2). Ligands activating these G protein-coupled receptors (GPCRs) include the phytocannabinoid Δ9-tetrahydrocannabinol, numerous synthetic compounds, and endogenous compounds known as endocannabinoids. Cannabinoid receptor antagonists have also been developed. Some of these ligands activate or block one type of cannabinoid receptor more potently than the other type. This review summarizes current data indicating the extent to which cannabinoid receptor ligands undergo orthosteric or allosteric interactions with non-CB1, non-CB2 established GPCRs, deorphanized receptors such as GPR55, ligand-gated ion channels, transient receptor potential (TRP) channels, and other ion channels or peroxisome proliferator-activated nuclear receptors. From these data, it is clear that some ligands that interact similarly with CB1 and/or CB2 receptors are likely to display significantly different pharmacological profiles. The review also lists some criteria that any novel “CB3” cannabinoid receptor or channel should fulfil and concludes that these criteria are not currently met by any non-CB1, non-CB2 pharmacological receptor or channel. However, it does identify certain pharmacological targets that should be investigated further as potential CB3 receptors or channels. These include TRP vanilloid 1, which possibly functions as an ionotropic cannabinoid receptor under physiological and/or pathological conditions, and some deorphanized GPCRs. Also discussed are 1) the ability of CB1 receptors to form heteromeric complexes with certain other GPCRs, 2) phylogenetic relationships that exist between CB1/CB2 receptors and other GPCRs, 3) evidence for the existence of several as-yet-uncharacterized non-CB1, non-CB2 cannabinoid receptors; and 4) current cannabinoid receptor nomenclature. PMID:21079038

International Union of Basic and Clinical Pharmacology. LXXIX. Cannabinoid receptors and their ligands: beyond CB₁ and CB₂.

PubMed

Pertwee, R G; Howlett, A C; Abood, M E; Alexander, S P H; Di Marzo, V; Elphick, M R; Greasley, P J; Hansen, H S; Kunos, G; Mackie, K; Mechoulam, R; Ross, R A

2010-12-01

There are at least two types of cannabinoid receptors (CB(1) and CB(2)). Ligands activating these G protein-coupled receptors (GPCRs) include the phytocannabinoid Δ(9)-tetrahydrocannabinol, numerous synthetic compounds, and endogenous compounds known as endocannabinoids. Cannabinoid receptor antagonists have also been developed. Some of these ligands activate or block one type of cannabinoid receptor more potently than the other type. This review summarizes current data indicating the extent to which cannabinoid receptor ligands undergo orthosteric or allosteric interactions with non-CB(1), non-CB(2) established GPCRs, deorphanized receptors such as GPR55, ligand-gated ion channels, transient receptor potential (TRP) channels, and other ion channels or peroxisome proliferator-activated nuclear receptors. From these data, it is clear that some ligands that interact similarly with CB(1) and/or CB(2) receptors are likely to display significantly different pharmacological profiles. The review also lists some criteria that any novel "CB(3)" cannabinoid receptor or channel should fulfil and concludes that these criteria are not currently met by any non-CB(1), non-CB(2) pharmacological receptor or channel. However, it does identify certain pharmacological targets that should be investigated further as potential CB(3) receptors or channels. These include TRP vanilloid 1, which possibly functions as an ionotropic cannabinoid receptor under physiological and/or pathological conditions, and some deorphanized GPCRs. Also discussed are 1) the ability of CB(1) receptors to form heteromeric complexes with certain other GPCRs, 2) phylogenetic relationships that exist between CB(1)/CB(2) receptors and other GPCRs, 3) evidence for the existence of several as-yet-uncharacterized non-CB(1), non-CB(2) cannabinoid receptors; and 4) current cannabinoid receptor nomenclature.

Transient Receptor Potential Vanilloid-1 (TRPV1) Is a Mediator of Lung Toxicity for Coal Fly Ash Particulate Material

PubMed Central

Deering-Rice, Cassandra E.; Johansen, Mark E.; Roberts, Jessica K.; Thomas, Karen C.; Romero, Erin G.; Lee, Jeewoo; Yost, Garold S.; Veranth, John M.

2012-01-01

Environmental particulate matter (PM) pollutants adversely affect human health, but the molecular basis is poorly understood. The ion channel transient receptor potential vanilloid-1 (TRPV1) has been implicated as a sensor for environmental PM and a mediator of adverse events in the respiratory tract. The objectives of this study were to determine whether TRPV1 can distinguish chemically and physically unique PM that represents important sources of air pollution; to elucidate the molecular basis of TRPV1 activation by PM; and to ascertain the contributions of TRPV1 to human lung cell and mouse lung tissue responses exposed to an insoluble PM agonist, coal fly ash (CFA1). The major findings of this study are that TRPV1 is activated by some, but not all of the prototype PM materials evaluated, with rank-ordered responses of CFA1 > diesel exhaust PM > crystalline silica; TRP melastatin-8 is also robustly activated by CFA1, whereas other TRP channels expressed by airway sensory neurons and lung epithelial cells that may also be activated by CFA1, including TRPs ankyrin 1 (A1), canonical 4α (C4α), M2, V2, V3, and V4, were either slightly (TRPA1) or not activated by CFA1; activation of TRPV1 by CFA1 occurs via cell surface interactions between the solid components of CFA1 and specific amino acid residues of TRPV1 that are localized in the putative pore-loop region; and activation of TRPV1 by CFA1 is not exclusive in mouse lungs but represents a pathway by which CFA1 affects the expression of selected genes in lung epithelial cells and airway tissue. PMID:22155782

Lesioning of TRPV1 expressing primary afferent neurons prevents PAR-2 induced motility, but not mechanical hypersensitivity in the rat colon.

PubMed

Suckow, S K; Anderson, E M; Caudle, R M

2012-03-01

Proteinase activated receptor 2 (PAR-2) is expressed by many neurons in the colon, including primary afferent neurons that co-express transient receptor potential vanilloid 1 (TRPV1). Activation of PAR-2 receptors was previously found to enhance colonic motility, increase secretion and produce hypersensitivity to mechanical stimuli. This study examined the functional role of TRPV1/PAR-2 expressing neurons that innervate the colon by lesioning TRPV1 bearing neurons with the highly selective and potent TRPV1 agonist resiniferatoxin. Colonic motility in response to PAR-2 activation was evaluated in vitro using isolated segments of descending colon and in vivo using manometry. Colonic mechanical nociceptive thresholds were measured using colorectal distension. Transient receptor potential vanilloid 1 expressing neurons were selectively lesioned with resiniferatoxin. In vitro, the PAR-2 agonists, trypsin and SLIGRL did not alter contractions of colon segments when applied alone, however, the agents enhanced acetylcholine stimulated contraction. In vivo, PAR-2 agonists administered intraluminally induced contractions of the colon and produced hypersensitivity to colorectal distention. The PAR-2 agonist enhancement of colonic contraction was eliminated when TRPV1 expressing neurons were lesioned with resiniferatoxin, but the PAR-2 agonist induced hypersensitivity remained in the lesioned animals. Our findings indicate that TRPV1/PAR-2 expressing primary afferent neurons mediate an extrinsic motor reflex pathway in the colon. These data, coupled with our previous studies, also indicate that the recently described colospinal afferent neurons are nociceptive, suggesting that these neurons may be useful targets for the pharmacological control of pain in diseases such as irritable bowel syndrome. © 2011 Blackwell Publishing Ltd.

Ameliorating Endothelial Mitochondrial Dysfunction Restores Coronary Function via Transient Receptor Potential Vanilloid 1-Mediated Protein Kinase A/Uncoupling Protein 2 Pathway.

PubMed

Xiong, Shiqiang; Wang, Peijian; Ma, Liqun; Gao, Peng; Gong, Liuping; Li, Li; Li, Qiang; Sun, Fang; Zhou, Xunmei; He, Hongbo; Chen, Jing; Yan, Zhencheng; Liu, Daoyan; Zhu, Zhiming

2016-02-01

Coronary heart disease arising from atherosclerosis is a leading cause of cardiogenic death worldwide. Mitochondria are the principal source of reactive oxygen species (ROS), and defective oxidative phosphorylation by the mitochondrial respiratory chain contributes to ROS generation. Uncoupling protein 2 (UCP2), an adaptive antioxidant defense factor, protects against mitochondrial ROS-induced endothelial dysfunction in atherosclerosis. The activation of transient receptor potential vanilloid 1 (TRPV1) attenuates vascular dysfunction. Therefore, whether TRPV1 activation antagonizes coronary lesions by alleviating endothelial mitochondrial dysfunction and enhancing the activity of the protein kinase A/UCP2 pathway warrants examination. ApoE(-/-), ApoE(-/-)/TRPV1(-/-), and ApoE(-/-)/UCP2(-/-) mice were fed standard chow, a high-fat diet (HFD), or the HFD plus 0.01% capsaicin. HFD intake profoundly impaired coronary vasodilatation and myocardial perfusion and shortened the survival duration of ApoE(-/-) mice. TRPV1 or UCP2 deficiency exacerbated HFD-induced coronary dysfunction and was associated with increased ROS generation and reduced nitric oxide production in the endothelium. The activation of TRPV1 by capsaicin upregulated UCP2 expression via protein kinase A phosphorylation, thereby alleviating endothelial mitochondrial dysfunction and inhibiting mitochondrial ROS generation. In vivo, dietary capsaicin supplementation enhanced coronary relaxation and prolonged the survival duration of HFD-fed ApoE(-/-) mice. These effects were not observed in ApoE(-/-) mice lacking the TRPV1 or UCP2 gene. The upregulation of protein kinase A /UCP2 via TRPV1 activation ameliorates coronary dysfunction and prolongs the lifespan of atherosclerotic mice by ameliorating endothelial mitochondrial dysfunction. Dietary capsaicin supplementation may represent a promising intervention for the primary prevention of coronary heart disease. © 2015 American Heart Association, Inc.

Analysis of transient receptor potential ankyrin 1 (TRPA1) in frogs and lizards illuminates both nociceptive heat and chemical sensitivities and coexpression with TRP vanilloid 1 (TRPV1) in ancestral vertebrates.

PubMed

Saito, Shigeru; Nakatsuka, Kazumasa; Takahashi, Kenji; Fukuta, Naomi; Imagawa, Toshiaki; Ohta, Toshio; Tominaga, Makoto

2012-08-31

Transient receptor potential ankyrin 1 (TRPA1) and TRP vanilloid 1 (V1) perceive noxious temperatures and chemical stimuli and are involved in pain sensation in mammals. Thus, these two channels provide a model for understanding how different genes with similar biological roles may influence the function of one another during the course of evolution. However, the temperature sensitivity of TRPA1 in ancestral vertebrates and its evolutionary path are unknown as its temperature sensitivities vary among different vertebrate species. To elucidate the functional evolution of TRPA1, TRPA1s of the western clawed (WC) frogs and green anole lizards were characterized. WC frog TRPA1 was activated by heat and noxious chemicals that activate mammalian TRPA1. These stimuli also activated native sensory neurons and elicited nocifensive behaviors in WC frogs. Similar to mammals, TRPA1 was functionally co-expressed with TRPV1, another heat- and chemical-sensitive nociceptive receptor, in native sensory neurons of the WC frog. Green anole TRPA1 was also activated by heat and noxious chemical stimulation. These results suggest that TRPA1 was likely a noxious heat and chemical receptor and co-expressed with TRPV1 in the nociceptive sensory neurons of ancestral vertebrates. Conservation of TRPV1 heat sensitivity throughout vertebrate evolution could have changed functional constraints on TRPA1 and influenced the functional evolution of TRPA1 regarding temperature sensitivity, whereas conserving its noxious chemical sensitivity. In addition, our results also demonstrated that two mammalian TRPA1 inhibitors elicited different effect on the TRPA1s of WC frogs and green anoles, which can be utilized to clarify the structural bases for inhibition of TRPA1.

Analysis of Transient Receptor Potential Ankyrin 1 (TRPA1) in Frogs and Lizards Illuminates Both Nociceptive Heat and Chemical Sensitivities and Coexpression with TRP Vanilloid 1 (TRPV1) in Ancestral Vertebrates*

PubMed Central

Saito, Shigeru; Nakatsuka, Kazumasa; Takahashi, Kenji; Fukuta, Naomi; Imagawa, Toshiaki; Ohta, Toshio; Tominaga, Makoto

2012-01-01

Transient receptor potential ankyrin 1 (TRPA1) and TRP vanilloid 1 (V1) perceive noxious temperatures and chemical stimuli and are involved in pain sensation in mammals. Thus, these two channels provide a model for understanding how different genes with similar biological roles may influence the function of one another during the course of evolution. However, the temperature sensitivity of TRPA1 in ancestral vertebrates and its evolutionary path are unknown as its temperature sensitivities vary among different vertebrate species. To elucidate the functional evolution of TRPA1, TRPA1s of the western clawed (WC) frogs and green anole lizards were characterized. WC frog TRPA1 was activated by heat and noxious chemicals that activate mammalian TRPA1. These stimuli also activated native sensory neurons and elicited nocifensive behaviors in WC frogs. Similar to mammals, TRPA1 was functionally co-expressed with TRPV1, another heat- and chemical-sensitive nociceptive receptor, in native sensory neurons of the WC frog. Green anole TRPA1 was also activated by heat and noxious chemical stimulation. These results suggest that TRPA1 was likely a noxious heat and chemical receptor and co-expressed with TRPV1 in the nociceptive sensory neurons of ancestral vertebrates. Conservation of TRPV1 heat sensitivity throughout vertebrate evolution could have changed functional constraints on TRPA1 and influenced the functional evolution of TRPA1 regarding temperature sensitivity, whereas conserving its noxious chemical sensitivity. In addition, our results also demonstrated that two mammalian TRPA1 inhibitors elicited different effect on the TRPA1s of WC frogs and green anoles, which can be utilized to clarify the structural bases for inhibition of TRPA1. PMID:22791718

Sensitization of transient receptor potential vanilloid 1 by the prokineticin receptor agonist Bv8.

PubMed

Vellani, Vittorio; Colucci, Mariantonella; Lattanzi, Roberta; Giannini, Elisa; Negri, Lucia; Melchiorri, Pietro; McNaughton, Peter A

2006-05-10

Small mammalian proteins called the prokineticins [prokineticin 1 (PK1) and PK2] and two corresponding G-protein-coupled receptors [prokineticin receptor 1 (PKR1) and PKR2] have been identified recently, but the physiological role of the PK/PKR system remains mostly unexplored. Bv8, a protein extracted from frog skin, is a convenient and potent agonist for both PKR1 and PKR2, and injection of Bv8 in vivo causes a potent and long-lasting hyperalgesia. Here, we investigate the cellular basis of hyperalgesia caused by activation of PKRs. Bv8 caused increases in [Ca]i in a population of isolated dorsal root ganglion (DRG) neurons, which we identified as nociceptors, or sensors for painful stimuli, from their responses to capsaicin, bradykinin, mustard oil, or proteases. Bv8 enhanced the inward current carried by the heat and capsaicin receptor, transient receptor potential vanilloid 1 (TRPV1) via a pathway involving activation of protein kinase Cepsilon (PKCepsilon), because Bv8 caused translocation of PKCepsilon to the neuronal membrane and because PKC antagonists reduced both the enhancement of current carried by TRPV1 and behavioral hyperalgesia in rodents. The neuronal population expressing PKRs consisted partly of small peptidergic neurons and partly of neurons expressing the N52 marker for myelinated fibers. Using single-cell reverse transcriptase-PCR, we found that mRNA for PKR1 was mainly expressed in small DRG neurons. Exposure to GDNF (glial cell line-derived neurotrophic factor) induced de novo expression of functional receptors for Bv8 in a nonpeptidergic population of neurons. These results show that prokineticin receptors are expressed in nociceptors and cause heat hyperalgesia by sensitizing TRPV1 through activation of PKCepsilon. The results suggest a role for prokineticins in physiological inflammation and hyperalgesia.

Periaqueductal gray glutamatergic, cannabinoid and vanilloid receptor interplay in defensive behavior and aversive memory formation.

PubMed

Back, Franklin P; Carobrez, Antonio P

2018-06-01

Stimulation of the midbrain periaqueductal gray matter (PAG) in humans elicits sensations of fear and impending terror, and mediates predator defensive responses in rodents. In rats, pharmacological stimulation of the dorsolateral portion of the PAG (dlPAG) with N-Methyl-d-Aspartate (NMDA) induces aversive conditioning that acts as an unconditioned stimulus (US). In the present work, we investigated the interplay between the vanilloid TRPV1 and cannabinoid CB1 receptors in the NMDA-dlPAG defensive response and in subsequent aversive learning. Rats were subjected to dlPAG NMDA infusion in an olfactory conditioned stimulus (CS) task allowing the evaluation of immediate and long-term defensive behavioral responses during CS presentation. The results indicated that an intermediate dose of NMDA (50 pmol) induced both immediate and long-term effects. A sub-effective dose of NMDA (25 pmol) was potentiated by the TRPV1 receptor agonist capsaicin (CAP, 1 nmol) and the CB1 receptor antagonist, AM251 (200 pmol). CAP (10 nmol) or the combination of CAP (1 nmol) and AM251 (200 pmol) induced long-term effects without increasing immediate defensive responses. The glutamate release inhibitor riluzole (2 or 4 nmol) and the AMPA/kainate receptor antagonist DNQX (2 or 4 nmol) potentiated the immediate effects but blocked the long-term effects. The results showed that immediate defensive responses rely on NMDA receptors, and aversive learning on the fine-tuning of TRPV1, CB1, metabotropic glutamate and AMPA receptors located in pre- and postsynaptic membranes. In conclusion, the activity of the dlPAG determines core affective aspects of aversive memory formation controlled by local TRPV1/CB1 balance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cancer cachexia causes skeletal muscle damage via transient receptor potential vanilloid 2‐independent mechanisms, unlike muscular dystrophy

PubMed Central

Suzuki, Nobuyuki; Ohtake, Hitomi; Kamauchi, Shinya; Hashimoto, Naohiro; Kiyono, Tohru; Wakabayashi, Shigeo

2015-01-01

Abstract Background Muscle wasting during cancer cachexia contributes to patient morbidity. Cachexia‐induced muscle damage may be understood by comparing its symptoms with those of other skeletal muscle diseases, but currently available data are limited. Methods We modelled cancer cachexia in mice bearing Lewis lung carcinoma/colon adenocarcinoma and compared the associated muscle damage with that in a murine muscular dystrophy model (mdx mice). We measured biochemical and immunochemical parameters: amounts/localization of cytoskeletal proteins and/or Ca2+ signalling proteins related to muscle function and abnormality. We analysed intracellular Ca2+ mobilization and compared results between the two models. Involvement of Ca2+‐permeable channel transient receptor potential vanilloid 2 (TRPV2) was examined by inoculating Lewis lung carcinoma cells into transgenic mice expressing dominant‐negative TRPV2. Results Tumourigenesis caused loss of body and skeletal muscle weight and reduced muscle force and locomotor activity. Similar to mdx mice, cachexia muscles exhibited myolysis, reduced sarcolemmal sialic acid content, and enhanced lysosomal exocytosis and sarcolemmal localization of phosphorylated Ca2+/CaMKII. Abnormal autophagy and degradation of dystrophin also occurred. Unlike mdx muscles, cachexia muscles did not exhibit regeneration markers (centrally nucleated fibres), and levels of autophagic proteolytic pathway markers increased. While a slight accumulation of TRPV2 was observed in cachexia muscles, Ca2+ influx via TRPV2 was not elevated in cachexia‐associated myotubes, and the course of cachexia pathology was not ameliorated by dominant‐negative inhibition of TRPV2. Conclusions Thus, cancer cachexia may induce muscle damage through TRPV2‐independent mechanisms distinct from those in muscular dystrophy; this may help treat patients with tumour‐induced muscle wasting. PMID:27239414

Transient Receptor Potential Vanilloid 1 Expression Mediates Capsaicin-Induced Cell Death.

PubMed

Ramírez-Barrantes, Ricardo; Córdova, Claudio; Gatica, Sebastian; Rodriguez, Belén; Lozano, Carlo; Marchant, Ivanny; Echeverria, Cesar; Simon, Felipe; Olivero, Pablo

2018-01-01

The transient receptor potential (TRP) ion channel family consists of a broad variety of non-selective cation channels that integrate environmental physicochemical signals for dynamic homeostatic control. Involved in a variety of cellular physiological processes, TRP channels are fundamental to the control of the cell life cycle. TRP channels from the vanilloid (TRPV) family have been directly implicated in cell death. TRPV1 is activated by pain-inducing stimuli, including inflammatory endovanilloids and pungent exovanilloids, such as capsaicin (CAP). TRPV1 activation by high doses of CAP (>10 μM) leads to necrosis, but also exhibits apoptotic characteristics. However, CAP dose-response studies are lacking in order to determine whether CAP-induced cell death occurs preferentially via necrosis or apoptosis. In addition, it is not known whether cytosolic Ca 2+ and mitochondrial dysfunction participates in CAP-induced TRPV1-mediated cell death. By using TRPV1-transfected HeLa cells, we investigated the underlying mechanisms involved in CAP-induced TRPV1-mediated cell death, the dependence of CAP dose, and the participation of mitochondrial dysfunction and cytosolic Ca 2+ increase. Together, our results contribute to elucidate the pathophysiological steps that follow after TRPV1 stimulation with CAP. Low concentrations of CAP (1 μM) induce cell death by a mechanism involving a TRPV1-mediated rapid and transient intracellular Ca 2+ increase that stimulates plasma membrane depolarization, thereby compromising plasma membrane integrity and ultimately leading to cell death. Meanwhile, higher doses of CAP induce cell death via a TRPV1-independent mechanism, involving a slow and persistent intracellular Ca 2+ increase that induces mitochondrial dysfunction, plasma membrane depolarization, plasma membrane loss of integrity, and ultimately, cell death.

Participation of transient receptor potential vanilloid 1 in paclitaxel-induced acute visceral and peripheral nociception in rodents.

PubMed

Rossato, Mateus Fortes; Rigo, Flavia Karine; Oliveira, Sara Marchesan; Guerra, Gustavo Petri; Silva, Cássia Regina; Cunha, Thiago Mattar; Gomez, Marcus Vinícius; Ferreira, Juliano; Trevisan, Gabriela

2018-06-05

The clinical use of paclitaxel as a chemotherapeutic agent is limited by the severe acute and chronic hypersensitivity caused when it is administered via intraperitoneal or intravenous routes. Thus far, evidence has suggested that transient receptor potential vanilloid-1 (TRPV1) has a key role in the chronic neuropathy induced by paclitaxel. Despite this, the role of TRPV1 in paclitaxel -related acute nociception, especially the development of visceral nociception, has not been evaluated. Thus, the goal of this study was to evaluate the participation of TRPV1 in a model of acute nociception induced by paclitaxel in rats and mice. A single intraperitoneal (i.p.) paclitaxel administration (1 mg/kg, i.p.) produced an immediate visceral nociception response 1 h after administration, caused mechanical and heat hypersensitivity, and diminished burrowing behaviour 24 h after administration. These nociceptive responses were reduced by SB-366791 treatment (0.5 mg/kg, i.p., a TRPV1 antagonist). In addition, TRPV1-positive sensory fibre ablation (using resiniferatoxin, 200 µg/kg, s.c.) reduced visceral nociception and mechanical or heat hypersensitivity caused by paclitaxel injection. Similarly, TRPV1 deficient mice showed a pronounced reduction in mechanical allodynia to paclitaxel acute injection and did not develop heat hypersensitivity. Moreover, 24 h after its injection, paclitaxel induced chemical hypersensitivity to capsaicin (a TRPV1 agonist, 0.01 nmol/site) and increased TRPV1 immunoreactivity in the dorsal root ganglion and sciatic nerve. In conclusion, TRPV1 is involved in mechanical and heat hypersensitivity and spontaneous-pain behaviour induced 24 h after a single paclitaxel injection. This receptor is also involved in visceral nociception induced immediately after paclitaxel administration. Copyright © 2018 Elsevier B.V. All rights reserved.

Short-term increases in transient receptor potential vanilloid-1 mediate stress-induced enhancement of neuronal excitation.

PubMed

Weitlauf, Carl; Ward, Nicholas J; Lambert, Wendi S; Sidorova, Tatiana N; Ho, Karen W; Sappington, Rebecca M; Calkins, David J

2014-11-12

Progression of neurodegeneration in disease and injury is influenced by the response of individual neurons to stressful stimuli and whether this response includes mechanisms to counter declining function. Transient receptor potential (TRP) cation channels transduce a variety of disease-relevant stimuli and can mediate diverse stress-dependent changes in physiology, both presynaptic and postsynaptic. Recently, we demonstrated that knock-out or pharmacological inhibition of the TRP vanilloid-1 (TRPV1) capsaicin-sensitive subunit accelerates degeneration of retinal ganglion cell neurons and their axons with elevated ocular pressure, the critical stressor in the most common optic neuropathy, glaucoma. Here we probed the mechanism of the influence of TRPV1 on ganglion cell survival in mouse models of glaucoma. We found that induced elevations of ocular pressure increased TRPV1 in ganglion cells and its colocalization at excitatory synapses to their dendrites, whereas chronic elevation progressively increased ganglion cell Trpv1 mRNA. Enhanced TRPV1 expression in ganglion cells was transient and supported a reversal of the effect of TRPV1 on ganglion cells from hyperpolarizing to depolarizing, which was also transient. Short-term enhancement of TRPV1-mediated activity led to a delayed increase in axonal spontaneous excitation that was absent in ganglion cells from Trpv1(-/-) retina. In isolated ganglion cells, pharmacologically activated TRPV1 mobilized to discrete nodes along ganglion cell dendrites that corresponded to sites of elevated Ca(2+). These results suggest that TRPV1 may promote retinal ganglion cell survival through transient enhancement of local excitation and axonal activity in response to ocular stress. Copyright © 2014 the authors 0270-6474/14/3415369-13$15.00/0.

Low-Level Blast Exposure Increases Transient Receptor Potential Vanilloid 1 (TRPV1) Expression in the Rat Cornea

PubMed Central

Por, Elaine D.; Choi, Jae-Hyek; Lund, Brian J.

2016-01-01

ABSTRACT Background: Blast-related ocular injuries sustained by military personnel have led to rigorous efforts to elucidate the effects of blast exposure on neurosensory function. Recent studies have provided some insight into cognitive and visual deficits sustained following blast exposure; however, limited data are available on the effects of blast on pain and inflammatory processes. Investigation of these secondary effects of blast exposure is necessary to fully comprehend the complex pathophysiology of blast-related injuries. The overall purpose of this study is to determine the effects of single and repeated blast exposure on pain and inflammatory mediators in ocular tissues. Methods: A compressed air shock tube was used to deliver a single or repeated blast (68.0 ± 2.7 kPa) to anesthetized rats daily for 5 days. Immunohistochemistry was performed on ocular tissues to determine the expression of the transient receptor potential vanilloid 1 (TRPV1) channel, calcitonin gene-related peptide (CGRP), substance P (SP), and endothelin-1 (ET-1) following single and repeated blast exposure. Neutrophil infiltration and myeloperoxidase (MPO) expression were also assessed in blast tissues via immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) analysis, respectively. Results: TRPV1 expression was increased in rat corneas exposed to both single and repeated blast. Increased secretion of CGRP, SP, and ET-1 was also detected in rat corneas as compared to control. Moreover, repeated blast exposure resulted in neutrophil infiltration in the cornea and stromal layer as compared to control animals. Conclusion: Single and repeated blast exposure resulted in increased expression of TRPV1, CGRP, SP, and ET-1 as well as neutrophil infiltration. Collectively, these findings provide novel insight into the activation of pain and inflammation signaling mediators following blast exposure. PMID:27049881

Repeat low-level blast exposure increases transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1) expression in the trigeminal ganglion

PubMed Central

Burke, Teresa A.; Doyle Brackley, Allison; Jeske, Nathaniel A.; Cleland, Jeffery M.; Lund, Brian J.

2017-01-01

Blast-associated sensory and cognitive trauma sustained by military service members is an area of extensively studied research. Recent studies in our laboratory have revealed that low-level blast exposure increased expression of transient receptor potential vanilloid 1 (TRPV1) and endothelin-1 (ET-1), proteins well characterized for their role in mediating pain transmission, in the cornea. Determining the functional consequences of these alterations in protein expression is critical to understanding blast-related sensory trauma. Thus, the purpose of this study was to examine TRPV1 and ET-1 expression in ocular associated sensory tissues following primary and tertiary blast. A rodent model of blast injury was used in which anesthetized animals, unrestrained or restrained, received a single or repeat blast (73.8 ± 5.5 kPa) from a compressed air shock tube once or daily for five consecutive days, respectively. Behavioral and functional analyses were conducted to assess blast effects on nocifensive behavior and TRPV1 activity. Immunohistochemistry and Western Blot were also performed with trigeminal ganglia (TG) to determine TRPV1, ET-1 and glial fibrillary associated protein (GFAP) expression following blast. Increased TRPV1, ET-1 and GFAP were detected in the TG of animals exposed to repeat blast. Increased nocifensive responses were also observed in animals exposed to repeat, tertiary blast as compared to single blast and control. Moreover, decreased TRPV1 desensitization was observed in TG neurons exposed to repeat blast. Repeat, tertiary blast resulted in increased TRPV1, ET-1 and GFAP expression in the TG, enhanced nociception and decreased TRPV1 desensitization. PMID:28797041

Carboxyl-terminal Domain of Transient Receptor Potential Vanilloid 1 Contains Distinct Segments Differentially Involved in Capsaicin- and Heat-induced Desensitization*

PubMed Central

Joseph, John; Wang, Sen; Lee, Jongseok; Ro, Jin Y.; Chung, Man-Kyo

2013-01-01

Multiple Ca2+-dependent processes are involved in capsaicin-induced desensitization of transient receptor potential vanilloid 1 (TRPV1), but desensitization of TRPV1 by heat occurs even in the absence of extracellular Ca2+, although the mechanisms are unknown. In this study, we tested the hypothesis that capsaicin and heat desensitize TRPV1 through distinct mechanisms involving distinct structural segments of TRPV1. In HEK293 cells that heterologously express TRPV1, we found that heat-induced desensitization was not affected by the inclusion of intracellular ATP or alanine mutation of Lys155, both of which attenuate capsaicin-induced desensitization, suggesting that heat-induced desensitization occurs through mechanisms distinct from capsaicin-induced desensitization. To determine protein domains involved in heat-induced desensitization, we generated chimeric proteins between TRPV1 and TRPV3, a heat-gated channel lacking heat-induced desensitization. We found that TRPV1 with the carboxyl-terminal domain (CTD) of TRPV3 retained heat activation but was impaired in heat-induced desensitization. Further experiments using chimeric or deletion mutants within TRPV1 CTD indicated that the distal half of CTD regulates the activation and desensitization of TRPV1 in modality-specific manners. Within the distal CTD, we identified two segments that distinctly regulated capsaicin- and heat-induced desensitization. The results suggest that the activation and desensitization of TRPV1 by capsaicin and heat can be modulated differentially and disproportionally through different regions of TRPV1 CTD. Identifying the domains involved in thermal regulation of TRPV1 may facilitate the development of novel anti-hyperalgesic approaches aimed at attenuating activation and enhancing desensitization of TRPV1 by thermal stimuli. PMID:24174527

Lysophosphatidylcholine-induced cytotoxicity in osteoblast-like MG-63 cells: involvement of transient receptor potential vanilloid 2 (TRPV2) channels.

PubMed

Fallah, Abdallah; Pierre, Rachel; Abed, Elie; Moreau, Robert

2013-01-01

Epidemiological studies indicate that patients suffering from atherosclerosis are predisposed to develop osteoporosis. Accordingly, atherogenic determinants such as oxidized low density lipoprotein (OxLDL) particles have been shown to alter bone cell functions. In this work, we investigated the cytotoxicity of lysophosphatidylcholine (lysoPC), a major phospholipid component generated upon LDL oxidation, on bone-forming MG-63 osteoblast-like cells. Cell viability was reduced by lysoPC in a concentration-dependent manner with a LC50 of 18.7±0.7 μM. LysoPC-induced cell death was attributed to induction of both apoptosis and necrosis. Since impairment of intracellular calcium homeostasis is often involved in mechanism of cell death, we determined the involvement of calcium in lysoPC-induced cytotoxicity. LysoPC promoted a rapid and transient increase in intracellular calcium attributed to mobilization from calcium stores, followed by a sustained influx. Intracellular calcium mobilization was associated to phospholipase C (PLC)-dependent mobilization of calcium from the endoplasmic reticulum since inhibition of PLC or calcium depletion of reticulum endoplasmic with thapsigargin prevented the calcium mobilization. The calcium influx induced by lysoPC was abolished by inhibition of transient receptor potential vanilloid (TRPV) channels with ruthenium red whereas gadolinium, which inhibits canonical TRP (TRPC) channels, was without effect. Accordingly, expression of TRPV2 and TRPV4 were shown in MG-63 cells. The addition of TRPV2 inhibitor Tranilast in the incubation medium prevent the calcium influx triggered by lysoPC and reduced lysoPC-induced cytotoxicity whereas TRPV4 inhibitor RN 1734 was without effect, which confirms the involvement of TRPV2 activation in lysoPC-induced cell death.

Spontaneous calcium transients in human neural progenitor cells mediated by transient receptor potential channels.

PubMed

Morgan, Peter J; Hübner, Rayk; Rolfs, Arndt; Frech, Moritz J

2013-09-15

Calcium signals affect many developmental processes, including proliferation, migration, survival, and apoptosis, processes that are of particular importance in stem cells intended for cell replacement therapies. The mechanisms underlying Ca(2+) signals, therefore, have a role in determining how stem cells respond to their environment, and how these responses might be controlled in vitro. In this study, we examined the spontaneous Ca(2+) activity in human neural progenitor cells during proliferation and differentiation. Pharmacological characterization indicates that in proliferating cells, most activity is the result of transient receptor potential (TRP) channels that are sensitive to Gd(3+) and La(3+), with the more subtype selective antagonist Ruthenium red also reducing activity, suggesting the involvement of transient receptor potential vanilloid (TRPV) channels. In differentiating cells, Gd(3+) and La(3+)-sensitive TRP channels also appear to underlie the spontaneous activity; however, no sub-type-specific antagonists had any effect. Protein levels of TRPV2 and TRPV3 decreased in differentiated cells, which is demonstrated by western blot. Thus, it appears that TRP channels represent the main route of Ca(2+) entry in human neural progenitor cells (hNPCs), but the responsible channel types are subject to substitution under differentiating conditions. The level of spontaneous activity could be increased and decreased by lowering and raising the extracellular K(+) concentration. Proliferating cells in low K(+) slowed the cell cycle, with a disproportionate increased percentage of cells in G1 phase and a reduction in S phase. Taken together, these results suggest a link between external K(+) concentration, spontaneous Ca(2+) transients, and cell cycle distribution, which is able to influence the fate of stem and progenitor cells.

Nonpsychotropic plant cannabinoids, cannabidivarin (CBDV) and cannabidiol (CBD), activate and desensitize transient receptor potential vanilloid 1 (TRPV1) channels in vitro: potential for the treatment of neuronal hyperexcitability.

PubMed

Iannotti, Fabio Arturo; Hill, Charlotte L; Leo, Antonio; Alhusaini, Ahlam; Soubrane, Camille; Mazzarella, Enrico; Russo, Emilio; Whalley, Benjamin J; Di Marzo, Vincenzo; Stephens, Gary J

2014-11-19

Epilepsy is the most common neurological disorder, with over 50 million people worldwide affected. Recent evidence suggests that the transient receptor potential cation channel subfamily V member 1 (TRPV1) may contribute to the onset and progression of some forms of epilepsy. Since the two nonpsychotropic cannabinoids cannabidivarin (CBDV) and cannabidiol (CBD) exert anticonvulsant activity in vivo and produce TRPV1-mediated intracellular calcium elevation in vitro, we evaluated the effects of these two compounds on TRPV1 channel activation and desensitization and in an in vitro model of epileptiform activity. Patch clamp analysis in transfected HEK293 cells demonstrated that CBD and CBDV dose-dependently activate and rapidly desensitize TRPV1, as well as TRP channels of subfamily V type 2 (TRPV2) and subfamily A type 1 (TRPA1). TRPV1 and TRPV2 transcripts were shown to be expressed in rat hippocampal tissue. When tested on epileptiform neuronal spike activity in hippocampal brain slices exposed to a Mg(2+)-free solution using multielectrode arrays (MEAs), CBDV reduced both epileptiform burst amplitude and duration. The prototypical TRPV1 agonist, capsaicin, produced similar, although not identical effects. Capsaicin, but not CBDV, effects on burst amplitude were reversed by IRTX, a selective TRPV1 antagonist. These data suggest that CBDV antiepileptiform effects in the Mg(2+)-free model are not uniquely mediated via activation of TRPV1. However, TRPV1 was strongly phosphorylated (and hence likely sensitized) in Mg(2+)-free solution-treated hippocampal tissue, and both capsaicin and CBDV caused TRPV1 dephosphorylation, consistent with TRPV1 desensitization. We propose that CBDV effects on TRP channels should be studied further in different in vitro and in vivo models of epilepsy.

Local upregulation of transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 ion channels in rectosigmoid deep infiltrating endometriosis

PubMed Central

Bohonyi, Noémi; Pohóczky, Krisztina; Szalontai, Bálint; Perkecz, Anikó; Kovács, Krisztina; Kajtár, Béla; Orbán, Lajos; Varga, Tamás; Szegedi, Sarolta; Bódis, József; Koppán, Miklós

2017-01-01

Transient Receptor Potential Vanilloid 1 (TRPV1) and Transient Receptor Potential Ankyrin 1 (TRPA1) expressed mainly by primary sensory neurons function as major nociceptive integrators. They are also present on the rat endometrium in an oestrogen-regulated manner. TRPV1 is upregulated in peritoneal and ovarian endometriosis patients, but there is no information about TRPA1 and their pathophysiological significances. In this study, patients undergoing laparoscopic surgery were investigated: severe dysmenorrhoea due to rectosigmoid deep infiltrating endometriosis (n = 15), uterine fibroid-induced moderate dysmenorrhoea (n = 7) and tubal infertility with no pain (n = 6). TRPA1 and TRPV1 mRNA and protein expressions were determined by quantitative polymerase chain reaction and semi-quantitative immunohistochemistry from the endometrium samples taken by curettage. Results were correlated with the clinical characteristics including pain intensity. TRPA1 and TRPV1 receptors were expressed in the healthy human endometrium at mRNA and protein levels. Sparse, scattered cytoplasmic TRPA1 and TRPV1 immunopositivities were found in the stroma and epithelial layers. We detected upregulated mRNA levels in deep infiltrating endometriosis lesions, and TRPV1 gene expression was also elevated in autocontrol endometrium of deep infiltrating endometriosis patients. Histological scoring revealed significant TRPA1 and TRPV1 difference between deep infiltrating endometriosis stroma and epithelium, and in deep infiltrating endometriosis epithelium compared to control samples. Besides, we measured elevated stromal TRPV1 immunopositivity in deep infiltrating endometriosis. Stromal TRPA1 and TRPV1 immunoreactivities strongly correlated with dysmenorrhoea severity, as well TRPV1 expression on ectopic epithelial cells and macrophages with dyspareunia. Epithelial TRPA1 and stromal TRPV1 immunopositivity also positively correlated with dyschezia severity. We provide the first evidence for the presence of non-neuronal TRPA1 receptor in the healthy human endometrium and confirm the expression of TRPV1 channels. Their upregulations in rectosigmoid deep infiltrating endometriosis lesions and correlations with pain intensity suggest potential roles in pathophysiological mechanisms of the disease. PMID:28478727

Local upregulation of transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 ion channels in rectosigmoid deep infiltrating endometriosis.

PubMed

Bohonyi, Noémi; Pohóczky, Krisztina; Szalontai, Bálint; Perkecz, Anikó; Kovács, Krisztina; Kajtár, Béla; Orbán, Lajos; Varga, Tamás; Szegedi, Sarolta; Bódis, József; Helyes, Zsuzsanna; Koppán, Miklós

2017-01-01

Transient Receptor Potential Vanilloid 1 (TRPV1) and Transient Receptor Potential Ankyrin 1 (TRPA1) expressed mainly by primary sensory neurons function as major nociceptive integrators. They are also present on the rat endometrium in an oestrogen-regulated manner. TRPV1 is upregulated in peritoneal and ovarian endometriosis patients, but there is no information about TRPA1 and their pathophysiological significances. In this study, patients undergoing laparoscopic surgery were investigated: severe dysmenorrhoea due to rectosigmoid deep infiltrating endometriosis ( n = 15), uterine fibroid-induced moderate dysmenorrhoea ( n = 7) and tubal infertility with no pain ( n = 6). TRPA1 and TRPV1 mRNA and protein expressions were determined by quantitative polymerase chain reaction and semi-quantitative immunohistochemistry from the endometrium samples taken by curettage. Results were correlated with the clinical characteristics including pain intensity. TRPA1 and TRPV1 receptors were expressed in the healthy human endometrium at mRNA and protein levels. Sparse, scattered cytoplasmic TRPA1 and TRPV1 immunopositivities were found in the stroma and epithelial layers. We detected upregulated mRNA levels in deep infiltrating endometriosis lesions, and TRPV1 gene expression was also elevated in autocontrol endometrium of deep infiltrating endometriosis patients. Histological scoring revealed significant TRPA1 and TRPV1 difference between deep infiltrating endometriosis stroma and epithelium, and in deep infiltrating endometriosis epithelium compared to control samples. Besides, we measured elevated stromal TRPV1 immunopositivity in deep infiltrating endometriosis. Stromal TRPA1 and TRPV1 immunoreactivities strongly correlated with dysmenorrhoea severity, as well TRPV1 expression on ectopic epithelial cells and macrophages with dyspareunia. Epithelial TRPA1 and stromal TRPV1 immunopositivity also positively correlated with dyschezia severity. We provide the first evidence for the presence of non-neuronal TRPA1 receptor in the healthy human endometrium and confirm the expression of TRPV1 channels. Their upregulations in rectosigmoid deep infiltrating endometriosis lesions and correlations with pain intensity suggest potential roles in pathophysiological mechanisms of the disease.

A pathophysiological role of TRPV1 in ischemic injury after transient focal cerebral ischemia in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyanohara, Jun; Shirakawa, Hisashi, E-mail: shirakaw@pharm.kyoto-u.ac.jp; Sanpei, Kazuaki

Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel with high Ca{sup 2+} permeability, which functions as a polymodal nociceptor activated by heat, protons and several vanilloids, including capsaicin and anandamide. Although TRPV1 channels are widely distributed in the mammalian brain, their pathophysiological roles in the brain remain to be elucidated. In this study, we investigated whether TRPV1 is involved in cerebral ischemic injury using a middle cerebral artery (MCA) occlusion model in wild-type (WT) and TRPV1-knockout (KO) mice. For transient ischemia, the left MCA of C57BL/6 mice was occluded for 60 min and reperfused at 1 and 2more » days after ischemia. We found that neurological and motor deficits, and infarct volumes in TRPV1-KO mice were lower than those of WT mice. Consistent with these results, intracerebroventricular injection of a TRPV1 antagonist, capsazepine (20 nmol), 30 min before the onset of ischemia attenuated neurological and motor deficits and improved infarct size without influencing cerebral blood flow in the occluded MCA territory. The protective effect of capsazepine on ischemic brain damage was not observed in TRPV1-KO mice. WT and TRPV1-KO mice did not show any differences with respect to the increased number of Iba1-positive microglia/macrophages, GFAP-positive astrocytes, and Gr1-positive neutrophils at 1 and 2 days after cerebral ischemia. Taken together, we conclude that brain TRPV1 channels are activated by ischemic stroke and cause neurological and motor deficits and infarction after brain ischemia. - Highlights: • We investigated whether TRPV1 is involved in transient ischemic brain damage in mice. • Neurological deficits and infarct volumes were lower in TRPV1-KO mice than in WT mice. • Injection of a TRPV1 antagonist, capsazepine, attenuated neurological deficits and improved infarct size. • No differences in astrocytic or microglial activation were observed between WT and TRPV1-KO mice.« less

Analgesic effects of the novel semicarbazide-sensitive amine oxidase inhibitor SZV 1287 in mouse pain models with neuropathic mechanisms: Involvement of transient receptor potential vanilloid 1 and ankyrin 1 receptors.

PubMed

Horváth, Ádám; Tékus, Valéria; Bencze, Noémi; Szentes, Nikolett; Scheich, Bálint; Bölcskei, Kata; Szőke, Éva; Mócsai, Attila; Tóth-Sarudy, Éva; Mátyus, Péter; Pintér, Erika; Helyes, Zsuzsanna

2018-05-01

Semicarbazide-sensitive amine oxidase (SSAO) produces tissue irritants by deamination of primary amines, which activate transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) receptors expressed predominantly on nociceptors. Since there are no data about its functions in pain, we studied the effects and mechanisms of action of our novel SSAO inhibitor and dual TRPA1/TRPV1 antagonist multi-target drug SZV 1287 in different pain models. Acute chemonociception was induced by TRPV1 and TRPA1 activation (resiniferatoxin and formalin, respectively), chronic arthritis by K/BxN serum transfer, traumatic mononeuropathy by sciatic nerve ligation. SZV 1287 (20 mg/kg i.p.) was investigated in C57BL/6J wildtype (WT), TRPA1- (TRPA1 -/- ) and TRPV1-deficient (TRPV1 -/- ) mice. Paw mechanonociception was measured by aesthesiometry, thermonociception by hot plate, nocifensive behavior by licking duration, volume by plethysmometry, myeloperoxidase activity by luminescence and plasma extravasation by fluorescence imaging, glia activation in pain-related brain regions by immunohistochemistry. SZV 1287 significantly inhibited both TRPA1 and TRPV1 activation-induced acute chemonociception and hyperalgesia. In K/BxN arthritis, daily SZV 1287 injections significantly decreased hyperalgesia, L4-L6 spinal dorsal horn microgliosis, edema and myeloperoxidase activity. SZV 1287-evoked antihyperalgesic and anti-edema effects were absent in TRPV1 -/- , and remarkably reduced in TRPA1 -/- mice. In contrast, myeloperoxidase-inhibitory effect was absent in TRPA1 -/-, but not in TRPV1 -/- animals. Acute SZV 1287 administration resulted in approximately 50% significant reduction of neuropathic hyperalgesia 7 days after nerve ligation, which was not observed in either TRPA1 -/- or TRPV1 -/- mice. SZV 1287 inhibits chronic inflammatory and neuropathic pain via TRPV1 and TRPA1/TRPV1 activation, respectively, highlighting its drug developmental potential. Copyright © 2018 Elsevier Ltd. All rights reserved.

Inhibition of transient receptor potential vanilloid-1 confers neuroprotection, reduces tumor necrosis factor-alpha, and increases IL-10 in a rat stroke model.

PubMed

Hakimizadeh, Elham; Shamsizadeh, Ali; Roohbakhsh, Ali; Arababadi, Mohammad Kazemi; Hajizadeh, Mohammad R; Shariati, Mehdi; Rahmani, Mohammad R; Allahtavakoli, Mohammad

2017-08-01

Stroke is a major cause of mortality and long-term disability in adults. Transient receptor potential vanilloid-1 (TRPV1) plays a crucial role in neuroinflammation. In this study, the effects of TRPV1 agonist (capsaicin) and antagonist (AMG9810) on cerebral ischemia were investigated. Forty male Wistar rats were assigned to the following experimental groups: sham, vehicle) ischemic), AMG9810 (selective TRPV1 antagonist, 0.5 mg/kg; 3 h after stroke), and capsaicin (1 mg/kg; 3 h after stroke). Stroke was induced by permanent middle cerebral artery occlusion and neurological deficits were evaluated 1, 3, and 7 days after stroke. Then, infarct volume, brain edema, body temperature, mRNA expression of TRPV1, and serum concentrations of tumor necrosis factor-alpha (TNF-α) and IL-10 were measured. Compared to the vehicle group, AMG9810 significantly decreased the infarct volume (P < 0.01). Latency for the removal of sticky labels from the forepaw and the hanging time were significantly decreased and increased, respectively, following administration of AMG9810 (P < 0.01 and P < 0.001 vs. vehicle) 3 and 7 days after stroke. Compared to the sham group, the mRNA expression of TRPV1 was significantly increased in vehicle group (P < 0.01). Administration of AMG9810 significantly increased the anti-inflammatory cytokine IL-10 and decreased the inflammatory cytokine TNF-α (P < 0.05). Moreover, our results indicate that AMG9810 might a promising candidate for the hypothermic treatment of stroke. The findings also suggest a key role for AMG9810 in reducing inflammation after stroke and imply that TRPV1 could be a potential target for the treatment of ischemic stroke. © 2017 Société Française de Pharmacologie et de Thérapeutique.

Gingerols: a novel class of vanilloid receptor (VR1) agonists

PubMed Central

Dedov, Vadim N; Tran, Van H; Duke, Colin C; Connor, Mark; Christie, MacDonald J; Mandadi, Sravan; Roufogalis, Basil D

2002-01-01

Gingerols, the pungent constituents of ginger, were synthesized and assessed as agonists of the capsaicin-activated VR1 (vanilloid) receptor. [6]-Gingerol and [8]-gingerol evoked capsaicin-like intracellular Ca2+ transients and ion currents in cultured DRG neurones. These effects of gingerols were blocked by capsazepine, the VR1 receptor antagonist. The potency of gingerols increased with increasing size of the side chain and with the overall hydrophobicity in the series. We conclude that gingerols represent a novel class of naturally occurring VR1 receptor agonists that may contribute to the medicinal properties of ginger, which have been known for centuries. The gingerol structure may be used as a template for the development of drugs acting as moderately potent activators of the VR1 receptor. PMID:12411409

Dietary Capsaicin Protects Cardiometabolic Organs from Dysfunction

PubMed Central

Sun, Fang; Xiong, Shiqiang; Zhu, Zhiming

2016-01-01

Chili peppers have a long history of use for flavoring, coloring, and preserving food, as well as for medical purposes. The increased use of chili peppers in food is very popular worldwide. Capsaicin is the major pungent bioactivator in chili peppers. The beneficial effects of capsaicin on cardiovascular function and metabolic regulation have been validated in experimental and population studies. The receptor for capsaicin is called the transient receptor potential vanilloid subtype 1 (TRPV1). TRPV1 is ubiquitously distributed in the brain, sensory nerves, dorsal root ganglia, bladder, gut, and blood vessels. Activation of TRPV1 leads to increased intracellular calcium signaling and, subsequently, various physiological effects. TRPV1 is well known for its prominent roles in inflammation, oxidation stress, and pain sensation. Recently, TRPV1 was found to play critical roles in cardiovascular function and metabolic homeostasis. Experimental studies demonstrated that activation of TRPV1 by capsaicin could ameliorate obesity, diabetes, and hypertension. Additionally, TRPV1 activation preserved the function of cardiometabolic organs. Furthermore, population studies also confirmed the beneficial effects of capsaicin on human health. The habitual consumption of spicy foods was inversely associated with both total and certain causes of specific mortality after adjustment for other known or potential risk factors. The enjoyment of spicy flavors in food was associated with a lower prevalence of obesity, type 2 diabetes, and cardiovascular diseases. These results suggest that capsaicin and TRPV1 may be potential targets for the management of cardiometabolic vascular diseases and their related target organs dysfunction. PMID:27120617

TRP channels and traffic-related environmental pollution-induced pulmonary disease

PubMed Central

Akopian, Armen N.; Fanick, E. Robert

2016-01-01

Environmental pollutant exposures are major risk factors for adverse health outcomes, with increased morbidity and mortality in humans. Diesel exhaust (DE) is one of the major harmful components of traffic-related air pollution. Exposure to DE affects several physiological systems, including the airways, and pulmonary diseases are increased in highly populated urban areas. Hence, there are urgent needs to (1) create newer and lesser polluting fuels, (2) improve exhaust aftertreatments and reduce emissions, and (3) understand mechanisms of actions for toxic effects of both conventional and cleaner diesel fuels on the lungs. These steps could aid the development of diagnostics and interventions to prevent the negative impact of traffic-related air pollution on the pulmonary system. Exhaust from conventional, and to a lesser extent, clean fuels, contains particulate matter (PM) and more than 400 additional chemical constituents. The major toxic constituents are nitrogen oxides (NOx) and polycyclic aromatic hydrocarbons (PAHs). PM and PAHs could potentially act via transient receptor potential (TRP) channels. In this review, we will first discuss the associations between DE from conventional as well as clean fuel technologies and acute and chronic airway inflammation. We will then review possible activation and/or potentiation of TRP vanilloid type 1 (TRPV1) and ankyrin 1 (TRPA1) channels by PM and PAHs. Finally, we will discuss and summarize recent findings on the mechanisms whereby TRPs could control the link between DE and airway inflammation, which is a primary determinant leading to pulmonary disease. PMID:26837756

TRP channels and traffic-related environmental pollution-induced pulmonary disease.

PubMed

Akopian, Armen N; Fanick, E Robert; Brooks, Edward G

2016-05-01

Environmental pollutant exposures are major risk factors for adverse health outcomes, with increased morbidity and mortality in humans. Diesel exhaust (DE) is one of the major harmful components of traffic-related air pollution. Exposure to DE affects several physiological systems, including the airways, and pulmonary diseases are increased in highly populated urban areas. Hence, there are urgent needs to (1) create newer and lesser polluting fuels, (2) improve exhaust aftertreatments and reduce emissions, and (3) understand mechanisms of actions for toxic effects of both conventional and cleaner diesel fuels on the lungs. These steps could aid the development of diagnostics and interventions to prevent the negative impact of traffic-related air pollution on the pulmonary system. Exhaust from conventional, and to a lesser extent, clean fuels, contains particulate matter (PM) and more than 400 additional chemical constituents. The major toxic constituents are nitrogen oxides (NOx) and polycyclic aromatic hydrocarbons (PAHs). PM and PAHs could potentially act via transient receptor potential (TRP) channels. In this review, we will first discuss the associations between DE from conventional as well as clean fuel technologies and acute and chronic airway inflammation. We will then review possible activation and/or potentiation of TRP vanilloid type 1 (TRPV1) and ankyrin 1 (TRPA1) channels by PM and PAHs. Finally, we will discuss and summarize recent findings on the mechanisms whereby TRPs could control the link between DE and airway inflammation, which is a primary determinant leading to pulmonary disease.

Loss of TRPV2 Homeostatic Control of Cell Proliferation Drives Tumor Progression

PubMed Central

Liberati, Sonia; Morelli, Maria Beatrice; Amantini, Consuelo; Farfariello, Valerio; Santoni, Matteo; Conti, Alessandro; Nabissi, Massimo; Cascinu, Stefano; Santoni, Giorgio

2014-01-01

Herein we evaluate the involvement of the TRPV2 channel, belonging to the Transient Receptor Potential Vanilloid channel family (TRPVs), in development and progression of different tumor types. In normal cells, the activation of TRPV2 channels by growth factors, hormones, and endocannabinoids induces a translocation of the receptor from the endosomal compartment to the plasma membrane, which results in abrogation of cell proliferation and induction of cell death. Consequently, loss or inactivation of TRPV2 signaling (e.g., glioblastomas), induces unchecked proliferation, resistance to apoptotic signals and increased resistance to CD95-induced apoptotic cell death. On the other hand, in prostate cancer cells, Ca2+-dependent activation of TRPV2 induced by lysophospholipids increases the invasion of tumor cells. In addition, the progression of prostate cancer to the castration-resistant phenotype is characterized by de novo TRPV2 expression, with higher TRPV2 transcript levels in patients with metastatic cancer. Finally, TRPV2 functional expression in tumor cells can also depend on the presence of alternative splice variants of TRPV2 mRNA that act as dominant-negative mutant of wild-type TRPV2 channels, by inhibiting its trafficking and translocation to the plasma membrane. In conclusion, as TRP channels are altered in human cancers, and their blockage impair tumor progression, they appear to be a very promising targets for early diagnosis and chemotherapy. PMID:24709905

Loss of TRPV2 Homeostatic Control of Cell Proliferation Drives Tumor Progression.

PubMed

Liberati, Sonia; Morelli, Maria Beatrice; Amantini, Consuelo; Farfariello, Valerio; Santoni, Matteo; Conti, Alessandro; Nabissi, Massimo; Cascinu, Stefano; Santoni, Giorgio

2014-02-19

Herein we evaluate the involvement of the TRPV2 channel, belonging to the Transient Receptor Potential Vanilloid channel family (TRPVs), in development and progression of different tumor types. In normal cells, the activation of TRPV2 channels by growth factors, hormones, and endocannabinoids induces a translocation of the receptor from the endosomal compartment to the plasma membrane, which results in abrogation of cell proliferation and induction of cell death. Consequently, loss or inactivation of TRPV2 signaling (e.g., glioblastomas), induces unchecked proliferation, resistance to apoptotic signals and increased resistance to CD95-induced apoptotic cell death. On the other hand, in prostate cancer cells, Ca2+-dependent activation of TRPV2 induced by lysophospholipids increases the invasion of tumor cells. In addition, the progression of prostate cancer to the castration-resistant phenotype is characterized by de novo TRPV2 expression, with higher TRPV2 transcript levels in patients with metastatic cancer. Finally, TRPV2 functional expression in tumor cells can also depend on the presence of alternative splice variants of TRPV2 mRNA that act as dominant-negative mutant of wild-type TRPV2 channels, by inhibiting its trafficking and translocation to the plasma membrane. In conclusion, as TRP channels are altered in human cancers, and their blockage impair tumor progression, they appear to be a very promising targets for early diagnosis and chemotherapy.

Canonical Transient Receptor Potential (TRPC) 1 Acts as a Negative Regulator for Vanilloid TRPV6-mediated Ca2+ Influx*

PubMed Central

Schindl, Rainer; Fritsch, Reinhard; Jardin, Isaac; Frischauf, Irene; Kahr, Heike; Muik, Martin; Riedl, Maria Christine; Groschner, Klaus; Romanin, Christoph

2012-01-01

TRP proteins mostly assemble to homomeric channels but can also heteromerize, preferentially within their subfamilies. The TRPC1 protein is the most versatile member and forms various TRPC channel combinations but also unique channels with the distantly related TRPP2 and TRPV4. We show here a novel cross-family interaction between TRPC1 and TRPV6, a Ca2+ selective member of the vanilloid TRP subfamily. TRPV6 exhibited substantial co-localization and in vivo interaction with TRPC1 in HEK293 cells, however, no interaction was observed with TRPC3, TRPC4, or TRPC5. Ca2+ and Na+ currents of TRPV6-overexpressing HEK293 cells are significantly reduced by co-expression of TRPC1, correlating with a dramatically suppressed plasma membrane targeting of TRPV6. In line with their intracellular retention, remaining currents of TRPC1 and TRPV6 co-expression resemble in current-voltage relationship that of TRPV6. Studying the N-terminal ankyrin like repeat domain, structurally similar in the two proteins, we have found that these cytosolic segments were sufficient to mediate a direct heteromeric interaction. Moreover, the inhibitory role of TRPC1 on TRPV6 influx was also maintained by expression of only its N-terminal ankyrin-like repeat domain. Our experiments provide evidence for a functional interaction of TRPC1 with TRPV6 that negatively regulates Ca2+ influx in HEK293 cells. PMID:22932896

Membrane-tethered peptides patterned after the TRP domain (TRPducins) selectively inhibit TRPV1 channel activity.

PubMed

Valente, Pierluigi; Fernández-Carvajal, Asia; Camprubí-Robles, María; Gomis, Ana; Quirce, Susana; Viana, Félix; Fernández-Ballester, Gregorio; González-Ros, José M; Belmonte, Carlos; Planells-Cases, Rosa; Ferrer-Montiel, Antonio

2011-05-01

The transient receptor potential vanilloid 1 (TRPV1) channel is a thermosensory receptor implicated in diverse physiological and pathological processes. The TRP domain, a highly conserved region in the C terminus adjacent to the internal channel gate, is critical for subunit tetramerization and channel gating. Here, we show that cell-penetrating, membrane-anchored peptides patterned after this protein domain are moderate and selective TRPV1 antagonists both in vitro and in vivo, blocking receptor activity in intact rat primary sensory neurons and their peripheral axons with mean decline time of 30 min. The most potent lipopeptide, TRP-p5, blocked all modes of TRPV1 gating with micromolar efficacy (IC(50)<10 μM), without significantly affecting other thermoTRP channels. In contrast, its retrosequence or the corresponding sequences of other TRPV channels did not alter TRPV1 channel activity (IC(50)>100 μM). TRP-p5 did not affect the capsaicin sensitivity of the vanilloid receptor. Our data suggest that TRP-p5 interferes with protein-protein interactions at the level of the TRP domain that are essential for the "conformational" change that leads to gate opening. Therefore, these palmitoylated peptides, which we termed TRPducins, are noncompetitive, voltage-independent, sequence-specific TRPV1 blockers. Our findings indicate that TRPducin-like peptides may embody a novel molecular strategy that can be exploited to generate a selective pharmacological arsenal for the TRP superfamily of ion channels.

[Upregulation of P2X3 receptors in dorsal root ganglion of TRPV1 knockout female mice].

PubMed

Fang, Xiao; Shi, Xiao-Han; Huang, Li-Bin; Rong, Wei-Fang; Ma, Bei

2014-08-25

The study was aimed to investigate the changes in mechanical pain threshold in the condition of chronic inflammatory pain after transient receptor potential vanilloid 1 (TRPV1) gene was knockout. Hind-paw intraplantar injection of complete freund's adjuvant (CFA, 20 μL) produced peripheral inflammation in wild-type and TRPV1 knockout female mice. The mechanical pain thresholds were measured during the 8 days after injection and pre-injection by using Von-Frey hair. Nine days after injection, mice were killed and the differences of expression of c-Fos and P2X3 receptor in the dorsal root ganglia (DRG) and spinal cord dorsal horn were examined by Western blotting between the two groups. Compared with that in wild-type mice, the mechanical pain threshold was increased significantly in TRPV1 knockout mice (P < 0.05); 3 days after CFA injection, the baseline mechanical pain threshold in the TRPV1 knockout mice group was significantly higher than that in the wild-type mice group (P < 0.05); The result of Western blotting showed that the expression of c-Fos protein both in DRG and spinal cord dorsal horn of TRPV1 knockout mice group was decreased significantly compared with that in wild-type mice group (P < 0.01, P < 0.05), while the expression of P2X3 receptor in DRG of TRPV1 knockout mice group was increased significantly compared with that in wild-type mice group (P < 0.05). Our findings indicate that TRPV1 may influence the peripheral mechanical pain threshold by mediating the expression of c-Fos protein both in DRG and spinal cord dorsal horn and changing the expression of P2X3 receptor in DRG.

Differences in chloride gradients allow for three distinct types of synaptic modulation by endocannabinoids.

PubMed

Wang, Yanqing; Burrell, Brian D

2016-08-01

Endocannabinoids can elicit persistent depression of excitatory and inhibitory synapses, reducing or enhancing (disinhibiting) neural circuit output, respectively. In this study, we examined whether differences in Cl(-) gradients can regulate which synapses undergo endocannabinoid-mediated synaptic depression vs. disinhibition using the well-characterized central nervous system (CNS) of the medicinal leech, Hirudo verbana Exogenous application of endocannabinoids or capsaicin elicits potentiation of pressure (P) cell synapses and depression of both polymodal (Npoly) and mechanical (Nmech) nociceptive synapses. In P synapses, blocking Cl(-) export prevented endocannabinoid-mediated potentiation, consistent with a disinhibition process that has been indicated by previous experiments. In Nmech neurons, which are depolarized by GABA due to an elevated Cl(-) equilibrium potentials (ECl), endocannabinoid-mediated depression was prevented by blocking Cl(-) import, indicating that this decrease in synaptic signaling was due to depression of excitatory GABAergic input (disexcitation). Npoly neurons are also depolarized by GABA, but endocannabinoids elicit depression in these synapses directly and were only weakly affected by disruption of Cl(-) import. Consequently, the primary role of elevated ECl may be to protect Npoly synapses from disinhibition. All forms of endocannabinoid-mediated plasticity required activation of transient potential receptor vanilloid (TRPV) channels. Endocannabinoid/TRPV-dependent synaptic plasticity could also be elicited by distinct patterns of afferent stimulation with low-frequency stimulation (LFS) eliciting endocannabinoid-mediated depression of Npoly synapses and high-frequency stimulus (HFS) eliciting endocannabinoid-mediated potentiation of P synapses and depression of Nmech synapses. These findings demonstrate a critical role of differences in Cl(-) gradients between neurons in determining the sign, potentiation vs. depression, of synaptic modulation under normal physiological conditions. Copyright © 2016 the American Physiological Society.

Differences in chloride gradients allow for three distinct types of synaptic modulation by endocannabinoids

PubMed Central

Wang, Yanqing

2016-01-01

Endocannabinoids can elicit persistent depression of excitatory and inhibitory synapses, reducing or enhancing (disinhibiting) neural circuit output, respectively. In this study, we examined whether differences in Cl− gradients can regulate which synapses undergo endocannabinoid-mediated synaptic depression vs. disinhibition using the well-characterized central nervous system (CNS) of the medicinal leech, Hirudo verbana. Exogenous application of endocannabinoids or capsaicin elicits potentiation of pressure (P) cell synapses and depression of both polymodal (Npoly) and mechanical (Nmech) nociceptive synapses. In P synapses, blocking Cl− export prevented endocannabinoid-mediated potentiation, consistent with a disinhibition process that has been indicated by previous experiments. In Nmech neurons, which are depolarized by GABA due to an elevated Cl− equilibrium potentials (ECl), endocannabinoid-mediated depression was prevented by blocking Cl− import, indicating that this decrease in synaptic signaling was due to depression of excitatory GABAergic input (disexcitation). Npoly neurons are also depolarized by GABA, but endocannabinoids elicit depression in these synapses directly and were only weakly affected by disruption of Cl− import. Consequently, the primary role of elevated ECl may be to protect Npoly synapses from disinhibition. All forms of endocannabinoid-mediated plasticity required activation of transient potential receptor vanilloid (TRPV) channels. Endocannabinoid/TRPV-dependent synaptic plasticity could also be elicited by distinct patterns of afferent stimulation with low-frequency stimulation (LFS) eliciting endocannabinoid-mediated depression of Npoly synapses and high-frequency stimulus (HFS) eliciting endocannabinoid-mediated potentiation of P synapses and depression of Nmech synapses. These findings demonstrate a critical role of differences in Cl− gradients between neurons in determining the sign, potentiation vs. depression, of synaptic modulation under normal physiological conditions. PMID:27226449

An Aversive Response to Osmotic Upshift in Caenorhabditis elegans

PubMed Central

Yu, Jingyi; Liu, He

2017-01-01

Abstract Environmental osmolarity presents a common type of sensory stimulus to animals. While behavioral responses to osmotic changes are important for maintaining a stable intracellular osmolarity, the underlying mechanisms are not fully understood. In the natural habitat of Caenorhabditis elegans, changes in environmental osmolarity are commonplace. It is known that the nematode acutely avoids shocks of extremely high osmolarity. Here, we show that C. elegans also generates gradually increased aversion of mild upshifts in environmental osmolarity. Different from an acute avoidance of osmotic shocks that depends on the function of a transient receptor potential vanilloid channel, the slow aversion to osmotic upshifts requires the cGMP-gated sensory channel subunit TAX-2. TAX-2 acts in several sensory neurons that are exposed to body fluid to generate the aversive response through a motor network that underlies navigation. Osmotic upshifts activate the body cavity sensory neuron URX, which is known to induce aversion upon activation. Together, our results characterize the molecular and cellular mechanisms underlying a novel sensorimotor response to osmotic stimuli and reveal that C. elegans engages different behaviors and the underlying mechanisms to regulate responses to extracellular osmolarity. PMID:28451641

Oxytocin Stimulates Extracellular Ca2+ Influx Through TRPV2 Channels in Hypothalamic Neurons to Exert Its Anxiolytic Effects.

PubMed

van den Burg, Erwin H; Stindl, Julia; Grund, Thomas; Neumann, Inga D; Strauss, Olaf

2015-12-01

There is growing interest in anxiolytic and pro-social effects of the neuropeptide oxytocin (OXT), but the underlying intraneuronal mechanisms are largely unknown. Here we examined OXT-mediated anxiolysis in the hypothalamic paraventricular nucleus (PVN) of rats and effects of OXT administration on signaling events in hypothalamic primary and immortalized cells. In vivo, the application of SKF96365 prevented the anxiolytic activity of OXT in the PVN, suggesting that changes in intracellular Ca(2+) mediate the acute OXT behavioral effects. In vitro, mainly in the neurons with autonomous Ca(2+) oscillations, OXT increased intracellular Ca(2+) concentration and oscillation amplitude. Pharmacological intervention revealed OXT-dependent changes in Ca(2+) signaling that required activation of transient receptor potential vanilloid type-2 channel (TRPV2), mediated by phosphoinositide 3-kinase. TRPV2 induced the activation of the anxiolytic mitogen-activated protein kinase kinase (MEK1/2). In situ, immunohistochemistry revealed co-localization of TRPV2 and OXT in the PVN. Thus, functional and pharmacological analyses identified TRPV2 as a mediator of anxiolytic effects of OXT, conveying the OXT signal to MEK1/2 via modulation of intracellular Ca(2+).

TRPV2 is critical for the maintenance of cardiac structure and function in mice

PubMed Central

Katanosaka, Yuki; Iwasaki, Keiichiro; Ujihara, Yoshihiro; Takatsu, Satomi; Nishitsuji, Koki; Kanagawa, Motoi; Sudo, Atsushi; Toda, Tatsushi; Katanosaka, Kimiaki; Mohri, Satoshi; Naruse, Keiji

2014-01-01

The heart has a dynamic compensatory mechanism for haemodynamic stress. However, the molecular details of how mechanical forces are transduced in the heart are unclear. Here we show that the transient receptor potential, vanilloid family type 2 (TRPV2) cation channel is critical for the maintenance of cardiac structure and function. Within 4 days of eliminating TRPV2 from hearts of the adult mice, cardiac function declines severely, with disorganization of the intercalated discs that support mechanical coupling with neighbouring myocytes and myocardial conduction defects. After 9 days, cell shortening and Ca2+ handling by single myocytes are impaired in TRPV2-deficient hearts. TRPV2-deficient neonatal cardiomyocytes form no intercalated discs and show no extracellular Ca2+-dependent intracellular Ca2+ increase and insulin-like growth factor (IGF-1) secretion in response to stretch stimulation. We further demonstrate that IGF-1 receptor/PI3K/Akt pathway signalling is significantly downregulated in TRPV2-deficient hearts, and that IGF-1 administration partially prevents chamber dilation and impairment in cardiac pump function in these hearts. Our results improve our understanding of the molecular processes underlying the maintenance of cardiac structure and function. PMID:24874017

Oxytocin Stimulates Extracellular Ca2+ Influx Through TRPV2 Channels in Hypothalamic Neurons to Exert Its Anxiolytic Effects

PubMed Central

van den Burg, Erwin H; Stindl, Julia; Grund, Thomas; Neumann, Inga D; Strauss, Olaf

2015-01-01

There is growing interest in anxiolytic and pro-social effects of the neuropeptide oxytocin (OXT), but the underlying intraneuronal mechanisms are largely unknown. Here we examined OXT-mediated anxiolysis in the hypothalamic paraventricular nucleus (PVN) of rats and effects of OXT administration on signaling events in hypothalamic primary and immortalized cells. In vivo, the application of SKF96365 prevented the anxiolytic activity of OXT in the PVN, suggesting that changes in intracellular Ca2+ mediate the acute OXT behavioral effects. In vitro, mainly in the neurons with autonomous Ca2+ oscillations, OXT increased intracellular Ca2+ concentration and oscillation amplitude. Pharmacological intervention revealed OXT-dependent changes in Ca2+ signaling that required activation of transient receptor potential vanilloid type-2 channel (TRPV2), mediated by phosphoinositide 3-kinase. TRPV2 induced the activation of the anxiolytic mitogen-activated protein kinase kinase (MEK1/2). In situ, immunohistochemistry revealed co-localization of TRPV2 and OXT in the PVN. Thus, functional and pharmacological analyses identified TRPV2 as a mediator of anxiolytic effects of OXT, conveying the OXT signal to MEK1/2 via modulation of intracellular Ca2+. PMID:26013963

TRPV2 is critical for the maintenance of cardiac structure and function in mice.

PubMed

Katanosaka, Yuki; Iwasaki, Keiichiro; Ujihara, Yoshihiro; Takatsu, Satomi; Nishitsuji, Koki; Kanagawa, Motoi; Sudo, Atsushi; Toda, Tatsushi; Katanosaka, Kimiaki; Mohri, Satoshi; Naruse, Keiji

2014-05-29

The heart has a dynamic compensatory mechanism for haemodynamic stress. However, the molecular details of how mechanical forces are transduced in the heart are unclear. Here we show that the transient receptor potential, vanilloid family type 2 (TRPV2) cation channel is critical for the maintenance of cardiac structure and function. Within 4 days of eliminating TRPV2 from hearts of the adult mice, cardiac function declines severely, with disorganization of the intercalated discs that support mechanical coupling with neighbouring myocytes and myocardial conduction defects. After 9 days, cell shortening and Ca(2+) handling by single myocytes are impaired in TRPV2-deficient hearts. TRPV2-deficient neonatal cardiomyocytes form no intercalated discs and show no extracellular Ca(2+)-dependent intracellular Ca(2+) increase and insulin-like growth factor (IGF-1) secretion in response to stretch stimulation. We further demonstrate that IGF-1 receptor/PI3K/Akt pathway signalling is significantly downregulated in TRPV2-deficient hearts, and that IGF-1 administration partially prevents chamber dilation and impairment in cardiac pump function in these hearts. Our results improve our understanding of the molecular processes underlying the maintenance of cardiac structure and function.

Lack of TRPV2 impairs thermogenesis in mouse brown adipose tissue.

PubMed

Sun, Wuping; Uchida, Kunitoshi; Suzuki, Yoshiro; Zhou, Yiming; Kim, Minji; Takayama, Yasunori; Takahashi, Nobuyuki; Goto, Tsuyoshi; Wakabayashi, Shigeo; Kawada, Teruo; Iwata, Yuko; Tominaga, Makoto

2016-03-01

Brown adipose tissue (BAT), a major site for mammalian non-shivering thermogenesis, could be a target for prevention and treatment of human obesity. Transient receptor potential vanilloid 2 (TRPV2), a Ca(2+)-permeable non-selective cation channel, plays vital roles in the regulation of various cellular functions. Here, we show that TRPV2 is expressed in brown adipocytes and that mRNA levels of thermogenic genes are reduced in both cultured brown adipocytes and BAT from TRPV2 knockout (TRPV2KO) mice. The induction of thermogenic genes in response to β-adrenergic receptor stimulation is also decreased in TRPV2KO brown adipocytes and suppressed by reduced intracellular Ca(2+) concentrations in wild-type brown adipocytes. In addition, TRPV2KO mice have more white adipose tissue and larger brown adipocytes and show cold intolerance, and lower BAT temperature increases in response to β-adrenergic receptor stimulation. Furthermore, TRPV2KO mice have increased body weight and fat upon high-fat-diet treatment. Based on these findings, we conclude that TRPV2 has a role in BAT thermogenesis and could be a target for human obesity therapy. © 2016 The Authors.

Involvement of TRPV1 channels in the periaqueductal grey on the modulation of innate fear responses.

PubMed

Aguiar, Daniele C; Almeida-Santos, Ana F; Moreira, Fabricio A; Guimarães, Francisco S

2015-04-01

The transient receptor potential vanilloid type-1 channel (TRPV1) is expressed in the midbrain periaqueductal grey (PAG), a region of the brain related to aversive responses. TRPV1 antagonism in the dorsolateral PAG (dlPAG) induces anxiolytic-like effects in models based on conflict situations. No study, however, has investigated whether these receptors could contribute to fear responses to proximal threat. Thus, we tested the hypothesis that TRPV1 in the PAG could mediate fear response in rats exposed to a predator. We verified whether exposure to a live cat (a natural predator) would activate TRPV1-expressing neurons in the PAG. Double-staining immunohistochemistry was used as a technique to detect c-Fos, a marker of neuronal activation, and TRPV1 expression. We also investigated whether intra-dlPAG injections of the TRPV1 antagonist, capsazepine (CPZ), would attenuate the behavioural consequences of predator exposure. Exposure to a cat increased c-Fos expression in TRPV1-positive neurons, mainly in the dorsal columns of the PAG, suggesting that TRPV1-expressing neurons are activated by threatening stimuli. Accordingly, local injection of CPZ inhibited the fear responses. These data support the hypothesis that TRPV1 channels mediate fear reactions in the dlPAG. This may have an implication for the development of TRPV1-antagonists as potential drugs for the treatment of certain psychiatric disorders.

Role of TRP channels in the cardiovascular system

PubMed Central

Yue, Zhichao; Xie, Jia; Yu, Albert S.; Stock, Jonathan; Du, Jianyang

2014-01-01

The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca2+-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca2+ entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases. PMID:25416190

Bidirectional electromagnetic control of the hypothalamus regulates feeding and metabolism

PubMed Central

Stanley, Sarah A.; Kelly, Leah; Latcha, Kaamashri N.; Schmidt, Sarah F.; Yu, Xiaofei; Nectow, Alexander R.; Sauer, Jeremy; Dyke, Jonathan P.; Dordick, Jonathan S.; Friedman, Jeffrey M.

2016-01-01

Targeted, temporally regulated neural modulation is invaluable in determining the physiological roles of specific neural populations or circuits. Here we describe a system for non-invasive, temporal activation or inhibition of neuronal activity in vivo and its use to study central nervous system control of glucose homeostasis and feeding in mice. We are able to induce neuronal activation remotely using radio waves or magnetic fields via Cre-dependent expression of a GFP-tagged ferritin fusion protein tethered to the cation-conducting transient receptor potential vanilloid 1 (TRPV1) by a camelid anti-GFP antibody (anti-GFP–TRPV1)1. Neuronal inhibition via the same stimuli is achieved by mutating the TRPV1 pore, rendering the channel chloride-permeable. These constructs were targeted to glucose-sensing neurons in the ventromedial hypothalamus in glucokinase–Cre mice, which express Cre in glucose-sensing neurons2. Acute activation of glucose-sensing neurons in this region increases plasma glucose and glucagon, lowers insulin levels and stimulates feeding, while inhibition reduces blood glucose, raises insulin levels and suppresses feeding. These results suggest that pancreatic hormones function as an effector mechanism of central nervous system circuits controlling blood glucose and behaviour. The method we employ obviates the need for permanent implants and could potentially be applied to study other neural processes or used to regulate other, even dispersed, cell types. PMID:27007848

The thermosensitive TRPV3 channel contributes to rapid wound healing in oral epithelia.

PubMed

Aijima, Reona; Wang, Bing; Takao, Tomoka; Mihara, Hiroshi; Kashio, Makiko; Ohsaki, Yasuyoshi; Zhang, Jing-Qi; Mizuno, Atsuko; Suzuki, Makoto; Yamashita, Yoshio; Masuko, Sadahiko; Goto, Masaaki; Tominaga, Makoto; Kido, Mizuho A

2015-01-01

The oral cavity provides an entrance to the alimentary tract to serve as a protective barrier against harmful environmental stimuli. The oral mucosa is susceptible to injury because of its location; nonetheless, it has faster wound healing than the skin and less scar formation. However, the molecular pathways regulating this wound healing are unclear. Here, we show that transient receptor potential vanilloid 3 (TRPV3), a thermosensitive Ca(2+)-permeable channel, is more highly expressed in murine oral epithelia than in the skin by quantitative RT-PCR. We found that temperatures above 33°C activated TRPV3 and promoted oral epithelial cell proliferation. The proliferation rate in the oral epithelia of TRPV3 knockout (TRPV3KO) mice was less than that of wild-type (WT) mice. We investigated the contribution of TRPV3 to wound healing using a molar tooth extraction model and found that oral wound closure was delayed in TRPV3KO mice compared with that in WT mice. TRPV3 mRNA was up-regulated in wounded tissues, suggesting that TRPV3 may contribute to oral wound repair. We identified TRPV3 as an essential receptor in heat-induced oral epithelia proliferation and wound healing. Our findings suggest that TRPV3 activation could be a potential therapeutic target for wound healing in skin and oral mucosa. © FASEB.

Role of TRP channels in the cardiovascular system.

PubMed

Yue, Zhichao; Xie, Jia; Yu, Albert S; Stock, Jonathan; Du, Jianyang; Yue, Lixia

2015-02-01

The transient receptor potential (TRP) superfamily consists of a large number of nonselective cation channels with variable degree of Ca(2+)-permeability. The 28 mammalian TRP channel proteins can be grouped into six subfamilies: canonical, vanilloid, melastatin, ankyrin, polycystic, and mucolipin TRPs. The majority of these TRP channels are expressed in different cell types including both excitable and nonexcitable cells of the cardiovascular system. Unlike voltage-gated ion channels, TRP channels do not have a typical voltage sensor, but instead can sense a variety of other stimuli including pressure, shear stress, mechanical stretch, oxidative stress, lipid environment alterations, hypertrophic signals, and inflammation products. By integrating multiple stimuli and transducing their activity to downstream cellular signal pathways via Ca(2+) entry and/or membrane depolarization, TRP channels play an essential role in regulating fundamental cell functions such as contraction, relaxation, proliferation, differentiation, and cell death. With the use of targeted deletion and transgenic mouse models, recent studies have revealed that TRP channels are involved in numerous cellular functions and play an important role in the pathophysiology of many diseases in the cardiovascular system. Moreover, several TRP channels are involved in inherited diseases of the cardiovascular system. This review presents an overview of current knowledge concerning the physiological functions of TRP channels in the cardiovascular system and their contributions to cardiovascular diseases. Ultimately, TRP channels may become potential therapeutic targets for cardiovascular diseases. Copyright © 2015 the American Physiological Society.

Nociceptin inhibits vanilloid TRPV-1-mediated neurosensitization induced by fenoterol in human isolated bronchi.

PubMed

Faisy, Christophe; Naline, Emmanuel; Rouget, Céline; Risse, Paul-André; Guerot, Emmanuel; Fagon, Jean-Yves; Chinet, Thierry; Roche, Nicolas; Advenier, Charles

2004-09-01

Chronic exposure to beta(2)-adrenoceptor agonists, especially fenoterol, has been shown to increase smooth muscle contraction to endothelin-1 in human bronchi partly through tachykinin-mediated pathways. The purpose of this work was to further investigate the role of sensory nerves in fenoterol-induced sensitization of human airways and the effect of nociceptin, a nociceptin/orphanin FQ (NOP) receptor agonist, on the increase in contraction after fenoterol exposure. Human bronchi from 62 patients were sensitized to endothelin-1 by prolonged incubation with fenoterol (0.1 microM, 15 h). The sensitizing effect of fenoterol was inhibited by high concentration of capsaicin (10 microM, 30 min before fenoterol sensitization), which induces depletion of mediators from sensory nerves, or co-incubation of fenoterol and capsazepine (1 microM), a vanilloid TRPV-1 receptor antagonist. Moreover, short pretreatment of bronchi with capsaicin (10 microM) or capsazepine (1 microM) after sensitization by fenoterol decreased the rise in smooth muscle contraction to endothelin-1. Nociceptin (1 microM) also inhibited the increased contraction in fenoterol-sensitized bronchi. Tertiapin (10 microM), an inhibitor of the inward-rectifier K(+) channels, but not naloxone (0.1 microM), a DOP/KOP/MOP receptor antagonist, prevented the inhibitory effect of nociceptin. In conclusion, fenoterol induces sensitization of human isolated bronchi to endothelin-1 in part through the stimulation of the vanilloid TRPV-1 receptor on tachykininergic sensory nerves. Nociceptin inhibits airway hyperresponsiveness via NOP receptor activation. This effect involves inward-rectifier K(+) channels.

Nociceptive vascular reflexes evoked by scorpion venom modulate cardiorespiratory parameters involving vanilloid receptor 1 in anaesthetised rats.

PubMed

Singh, Sanjeev K; Deshpande, Shripad B

2009-02-27

Involvement of vanilloid and 5-HT(3) receptors in the cardiorespiratory reflexes evoked by intra-arterial (i.a.) injection of Mesobuthus tamulus (BT) venom was examined. In anaesthetised rats, blood pressure, respiratory excursions and ECG were recorded for 60min after the injection of venom in the absence or presence of antagonists. Injection of BT venom (1mg/kg, i.a.) produced alterations in respiratory frequency (RF), blood pressure (BP) and heart rate (HR). The changes in RF were manifested as immediate increase (40%) followed by a decrease (40%) and subsequent sustained increase (60%). In case of BP, the increase began around 40s, peaked at 5min (50%) and remained above the initial level subsequently. The bradycardiac response began around 5min which peaked (50% of the initial) around 25min and remained at that level. Thus, exhibiting immediate-tachypnoeic, intermediate-hypertensive and delayed-bradycardiac responses. Pretreatment with lignocaine, blocked the respiratory responses and attenuated the pressor responses evoked by venom. Pretreatment with capsazepine, vanilloid receptor 1 (VR1) antagonist, antagonized all the three parameters of cardiorespiratory responses evoked by venom. Whereas, ondansetron (5-HT(3) antagonist) attenuated the pressor and bradycardiac responses significantly but not the respiratory responses. These observations indicate that the cardiorespiratory changes induced by intra-arterial injection of venom are carried by afferents in addition to somatic nerves, involving mainly VR1 receptors and partially by 5-HT(3) receptors.

Protease-activated receptor 2-mediated protection of myocardial ischemia-reperfusion injury: role of transient receptor potential vanilloid receptors

PubMed Central

Zhong, Beihua

2009-01-01

Activation of the protease-activated receptor 2 (PAR2) or the transient receptor potential vanilloid type 1 (TRPV1) channels expressed in cardiac sensory afferents containing calcitonin gene-related peptide (CGRP) and/or substance P (SP) has been proposed to play a protective role in myocardial ischemia-reperfusion (I/R) injury. However, the interaction between PAR2 and TRPV1 is largely unknown. Using gene-targeted TRPV1-null mutant (TRPV1−/−) or wild-type (WT) mice, we test the hypothesis that TRPV1 contributes to PAR2-mediated cardiac protection via increasing the release of CGRP and SP. Immunofluorescence labeling showed that TRPV1 coexpressed with PAR2, PKC-ε, or PKAc in cardiomyocytes, cardiac blood vessels, and perivascular nerves in WT but not TRPV1−/− hearts. WT or TRPV1−/− hearts were Langendorff perfused with the selective PAR2 agonist, SLIGRL, in the presence or absence of various antagonists, followed by 35 min of global ischemia and 40 min of reperfusion (I/R). The recovery rate of coronary flow, the maximum rate of left ventricular pressure development, left ventricular end-diastolic pressure, and left ventricular developed pressure were evaluated after I/R. SLIGRL improved the recovery of hemodynamic parameters, decreased lactate dehydrogenase release, and reduced the infarct size in both WT and TRPV1−/− hearts (P < 0.05). The protection of SLIGRL was significantly surpassed for WT compared with TRPV1−/− hearts (P < 0.05). CGRP8–37, a selective CGRP receptor antagonist, RP67580, a selective neurokinin-1 receptor antagonist, PKC-ε V1–2, a selective PKC-ε inhibitor, or H-89, a selective PKA inhibitor, abolished SLIGRL protection by inhibiting the recovery of the rate of coronary flow, maximum rate of left ventricular pressure development, and left ventricular developed pressure, and increasing left ventricular end-diastolic pressure in WT but not TRPV1−/− hearts. Radioimmunoassay showed that SLIGRL increased the release of CGRP and SP in WT but not TRPV1−/− hearts (P < 0.05), which were prevented by PKC-ε V1–2 and H-89. Thus our data show that PAR2 activation improves cardiac recovery after I/R injury in WT and TRPV1−/− hearts, with a greater effect in the former, suggesting that PAR2-mediated protection is TRPV1 dependent and independent, and that dysfunctional TRPV1 impairs PAR2 action. PAR2 activation of the PKC-ε or PKA pathway stimulates or sensitizes TRPV1 in WT hearts, leading to the release of CGRP and SP that contribute, at least in part, to PAR2-induced cardiac protection against I/R injury. PMID:19812353

Effects of piperine, the pungent component of black pepper, at the human vanilloid receptor (TRPV1)

PubMed Central

McNamara, Fergal N; Randall, Andrew; Gunthorpe, Martin J

2005-01-01

We have characterised the effects of piperine, a pungent alkaloid found in black pepper, on the human vanilloid receptor TRPV1 using whole-cell patch-clamp electrophysiology. Piperine produced a clear agonist activity at the human TRPV1 receptor yielding rapidly activating whole-cell currents that were antagonised by the competitive TRPV1 antagonist capsazepine and the non-competitive TRPV1 blocker ruthenium red. The current–voltage relationship of piperine-activated currents showed pronounced outward rectification (25±4-fold between −70 and +70 mV) and a reversal potential of 0.0±0.4 mV, which was indistinguishable from that of the prototypical TRPV1 agonist capsaicin. Although piperine was a less potent agonist (EC50=37.9±1.9 μM) than capsaicin (EC50=0.29±0.05 μM), it demonstrated a much greater efficacy (approximately two-fold) at TRPV1. This difference in efficacy did not appear to be related to the proton-mediated regulation of the receptor since a similar degree of potentiation was observed for responses evoked by piperine (230±20%, n=11) or capsaicin (284±32%, n=8) upon acidification to pH 6.5. The effects of piperine upon receptor desensitisation were also unable to explain this effect since piperine resulted in more pronounced macroscopic desensitisation (t1/2=9.9±0.7 s) than capsaicin (t1/2>20 s) and also caused greater tachyphylaxis in response to repetitive agonist applications. Overall, our data suggest that the effects of piperine at human TRPV1 are similar to those of capsaicin except for its propensity to induce greater receptor desensitisation and, rather remarkably, exhibit a greater efficacy than capsaicin itself. These results may provide insight into the TRPV1-mediated effects of piperine on gastrointestinal function. PMID:15685214

Advanced oxidation protein products sensitized the transient receptor potential vanilloid 1 via NADPH oxidase 1 and 4 to cause mechanical hyperalgesia.

PubMed

Ding, Ruoting; Jiang, Hui; Sun, Baihui; Wu, Xiaoliang; Li, Wei; Zhu, Siyuan; Liao, Congrui; Zhong, Zhaoming; Chen, Jianting

2016-12-01

Oxidative stress is a possible pathogenesis of hyperalgesia. Advanced oxidation protein products (AOPPs), a new family of oxidized protein compounds, have been considered as a novel marker of oxidative stress. However, the role of AOPPs in the mechanism of hyperalgesia remains unknown. Our study aims to investigate whether AOPPs have an effect on hyperalgesia and the possible underlying mechanisms. To identify the AOPPs involved, we induced hyperalgesia in rats by injecting complete Freund's adjuvant (CFA) in hindpaw. The level of plasma AOPPs in CFA-induced rats was 1.6-fold in comparison with what in normal rats (P<0.05). After intravenous injection of AOPPs-modified rat serum albumin (AOPPs-RSA) in Sprague-Dawley rats, the paw mechanical thresholds, measured by the electronic von Frey system, significantly declined. Immunofluorescence staining indicated that AOPPs increased expressions of NADPH oxidase 1 (Nox1), NADPH oxidase 4 (Nox4), transient receptor potential vanilloid 1 (TRPV1) and calcitonin gene-related peptide (CGRP) in the dorsal root ganglia (DRG) tissues. In-vitro studies were performed on primary DRG neurons which were obtained from both thoracic and lumbar DRG of rats. Results indicated that AOPPs triggered reactive oxygen species (ROS) production in DRG neurons, which were significantly abolished by ROS scavenger N-acetyl-l-cysteine (NAC) and small-interfering RNA (siRNA) silencing of Nox1 or Nox4. The expressions of Nox1, Nox4, TRPV1 and CGRP were significantly increased in AOPPs-induced DRG neurons. And relevant siRNA or inhibitors notably suppressed the expressions of these proteins and the calcium influxes in AOPPs-induced DRG neurons. In conclusion, AOPPs increased significantly in CFA-induced hyperalgesia rats and they activated Nox1/Nox4-ROS to sensitize TRPV1-dependent Ca2+ influx and CGRP release which led to inducing mechanical hyperalgesia. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

The role of endogenous molecules in modulating pain through transient receptor potential vanilloid 1 (TRPV1)

PubMed Central

Morales-Lázaro, Sara L; Simon, Sidney A; Rosenbaum, Tamara

2013-01-01

Pain is a physiological response to a noxious stimulus that decreases the quality of life of those sufferring from it. Research aimed at finding new therapeutic targets for the treatment of several maladies, including pain, has led to the discovery of numerous molecular regulators of ion channels in primary afferent nociceptive neurons. Among these receptors is TRPV1 (transient receptor potential vanilloid 1), a member of the TRP family of ion channels. TRPV1 is a calcium-permeable channel, which is activated or modulated by diverse exogenous noxious stimuli such as high temperatures, changes in pH, and irritant and pungent compounds, and by selected molecules released during tissue damage and inflammatory processes. During the last decade the number of endogenous regulators of TRPV1's activity has increased to include lipids that can negatively regulate TRPV1, as is the case for cholesterol and PIP2 (phosphatidylinositol 4,5-biphosphate) while, in contrast, other lipids produced in response to tissue injury and ischaemic processes are known to positively regulate TRPV1. Among the latter, lysophosphatidic acid activates TRPV1 while amines such as N-acyl-ethanolamines and N-acyl-dopamines can sensitize or directly activate TRPV1. It has also been found that nucleotides such as ATP act as mediators of chemically induced nociception and pain and gases, such as hydrogen sulphide and nitric oxide, lead to TRPV1 activation. Finally, the products of lipoxygenases and omega-3 fatty acids among other molecules, such as divalent cations, have also been shown to endogenously regulate TRPV1 activity. Here we provide a comprehensive review of endogenous small molecules that regulate the function of TRPV1. Acting through mechanisms that lead to sensitization and desensitization of TRPV1, these molecules regulate pathways involved in pain and nociception. Understanding how these compounds modify TRPV1 activity will allow us to comprehend how some pathologies are associated with its deregulation. PMID:23613529

The Transient Receptor Potential Vanilloid 2 Cation Channel Is Abundant in Macrophages Accumulating at the Peri-Infarct Zone and May Enhance Their Migration Capacity towards Injured Cardiomyocytes following Myocardial Infarction

PubMed Central

Goryainov, Pavel; Landa, Natalie; Barshack, Iris; Avivi, Camila; Semo, Jonathan; Keren, Gad

2014-01-01

Purpose A novel family of transient receptor potential (TRP) channels, that may hold a role in calcium homeostasis, has recently been described. By employing a GeneChip array analysis we have demonstrated a clear and specific upregulation of the TRP vanilloid 2 (TRPV2) mRNA in the left ventricles (LV) 3–5 days post-acute myocardial infarction (MI) compared to sham-operated controls, both in rats and in mice. We sought to characterize the cardiac cellular subpopulations in which TRPV2 is overexpressed upon acute MI. Methods Lewis rats underwent an acute MI by ligation of the left anterior descending artery or chest opening only (sham). The animals were terminated at various time points and an immunohistochemical (IHC) and immunofloerescent (IFC) staining of the LV sections as well as a flow cytometry analysis of LV-derived cells were carried out, using anti-TRPV2 and anti-monocyte/macrophage antibodies. Rat alveolar macrophage cells, NR8383, transiently transfected with TRPV2 siRNA were allowed to migrate towards hypoxic conditioned media of the rat cardiac myoblast line H9C2 using a trans-well migration assay. The macrophage cells migrating to the bottom side of the inserts were counted. Results The IHC and IFC staining as well as the flow cytometry data demonstrated a substantial expression of TRPV2 in infiltrating macrophages in the peri-infarct region 3–5 days post-acute MI. The in vitro migration assay data demonstrated that following inhibition of the TRPV2 channel, the number of migrating macrophages towards conditioned medium of hypoxic cardiomyocytes was significantly reduced. Conclusions TRPV2 is highly expressed on the peri-infarct infiltrating macrophages and may play an important role in post-MI phagocytosis. Better characterization of this channel may pave the way for identifying a new target for modulating the dramatic post-MI immune reactions. PMID:25136832

The role of endogenous molecules in modulating pain through transient receptor potential vanilloid 1 (TRPV1).

PubMed

Morales-Lázaro, Sara L; Simon, Sidney A; Rosenbaum, Tamara

2013-07-01

Pain is a physiological response to a noxious stimulus that decreases the quality of life of those sufferring from it. Research aimed at finding new therapeutic targets for the treatment of several maladies, including pain, has led to the discovery of numerous molecular regulators of ion channels in primary afferent nociceptive neurons. Among these receptors is TRPV1 (transient receptor potential vanilloid 1), a member of the TRP family of ion channels. TRPV1 is a calcium-permeable channel, which is activated or modulated by diverse exogenous noxious stimuli such as high temperatures, changes in pH, and irritant and pungent compounds, and by selected molecules released during tissue damage and inflammatory processes. During the last decade the number of endogenous regulators of TRPV1's activity has increased to include lipids that can negatively regulate TRPV1, as is the case for cholesterol and PIP2 (phosphatidylinositol 4,5-biphosphate) while, in contrast, other lipids produced in response to tissue injury and ischaemic processes are known to positively regulate TRPV1. Among the latter, lysophosphatidic acid activates TRPV1 while amines such as N-acyl-ethanolamines and N-acyl-dopamines can sensitize or directly activate TRPV1. It has also been found that nucleotides such as ATP act as mediators of chemically induced nociception and pain and gases, such as hydrogen sulphide and nitric oxide, lead to TRPV1 activation. Finally, the products of lipoxygenases and omega-3 fatty acids among other molecules, such as divalent cations, have also been shown to endogenously regulate TRPV1 activity. Here we provide a comprehensive review of endogenous small molecules that regulate the function of TRPV1. Acting through mechanisms that lead to sensitization and desensitization of TRPV1, these molecules regulate pathways involved in pain and nociception. Understanding how these compounds modify TRPV1 activity will allow us to comprehend how some pathologies are associated with its deregulation.

Influence of 1α, 25-dihydroxyvitamin D3 [1, 25(OH)2D3] on the expression of Sox 9 and the transient receptor potential vanilloid 5/6 ion channels in equine articular chondrocytes.

PubMed

Hdud, Ismail M; Loughna, Paul T

2014-01-01

Sox 9 is a major marker of chondrocyte differentiation. When chondrocytes are cultured in vitro they progressively de-differentiate and this is associated with a decline in Sox 9 expression. The active form of vitamin D, 1, 25 (OH)2D3 has been shown to be protective of cartilage in both humans and animals. In this study equine articular chondrocytes were grown in culture and the effects of 1, 25 (OH)2D3 upon Sox 9 expression examined. The expression of the transient receptor potential vanilloid (TRPV) ion channels 5 and 6 in equine chondrocytes in vitro, we have previously shown, is inversely correlated with de-differentiation. The expression of these channels in response to 1, 25 (OH)2D3 administration was therefore also examined. The active form of vitamin D (1, 25 (OH)2D3) when administered to cultured equine chondrocytes at two different concentrations significantly increased the expression of Sox 9 at both. In contrast 1, 25 (OH)2D3 had no significant effect upon the expression of either TRPV 5 or 6 at either the protein or the mRNA level. The increased expression of Sox 9, in equine articular chondrocytes in vitro, in response to the active form of vitamin D suggests that this compound could be utilized to inhibit the progressive de-differentiation that is normally observed in these cells. It is also supportive of previous studies indicating that 1α, 25-dihydroxyvitamin D3 can have a protective effect upon cartilage in animals in vivo. The previously observed correlation between the degree of differentiation and the expression levels of TRPV 5/6 had suggested that these ion channels may have a direct involvement in, or be modulated by, the differentiation process in vitro. The data in the present study do not support this.

Enhancement by citral of glutamatergic spontaneous excitatory transmission in adult rat substantia gelatinosa neurons.

PubMed

Zhu, Lan; Fujita, Tsugumi; Jiang, Chang-Yu; Kumamoto, Eiichi

2016-02-10

Although citral, which is abundantly present in lemongrass, has various actions including antinociception, how citral affects synaptic transmission has not been examined as yet. Citral activates in heterologous cells transient receptor potential vanilloid-1, ankyrin-1, and melastatin-8 (TRPV1, TRPA1, and TRPM8, respectively) channels, the activation of which in the spinal lamina II [substantia gelatinosa (SG)] increases the spontaneous release of L-glutamate from nerve terminals. It remains to be examined what types of transient receptor potential channel in native neurons are activated by citral. With a focus on transient receptor potential activation, we examined the effect of citral on glutamatergic spontaneous excitatory transmission using the whole-cell patch-clamp technique to SG neurons in adult rat spinal cord slices. Bath-applied citral for 3 min increased the frequency of spontaneous excitatory postsynaptic current in a concentration-dependent manner (half-maximal effective concentration=0.58 mM), with a small increase in its amplitude. The spontaneous excitatory postsynaptic current frequency increase produced by citral was repeated at a time interval of 30 min, albeit this action recovered with a slow time course after washout. The presynaptic effect of citral was inhibited by TRPA1 antagonist HC-030031, but not by voltage-gated Na-channel blocker tetrodotoxin, TRPV1 antagonist capsazepine, and TRPM8 antagonist BCTC. It is concluded that citral increases spontaneous L-glutamate release in SG neurons by activating TRPA1 channels. Considering that the SG plays a pivotal role in modulating nociceptive transmission from the periphery, the citral activity could contribute toward at least a part of the modulation.

Transient receptor potential ankyrin receptor 1 is a novel target for pro-tussive agents.

PubMed

Andrè, E; Gatti, R; Trevisani, M; Preti, D; Baraldi, P G; Patacchini, R; Geppetti, P

2009-11-01

The transient receptor potential ankyrin receptor 1 (TRPA1) is a cation channel, co-expressed with the pro-tussive transient receptor potential vanilloid type 1 (TRPV1) channel in primary sensory neurons. TRPA1 is activated by a series of irritant exogenous and endogenous alpha,beta-unsaturated aldehydes which seem to play a role in airway diseases. We investigated whether TRPA1 agonists provoke cough in guinea pigs and whether TRPA1 antagonists inhibit this response. Animals were placed in a Perspex box, and cough sounds were recorded and counted by observers unaware of the treatment used. Inhalation of two selective TRPA1 agonists, allyl isothiocyanate and cinnamaldehyde, dose-dependently caused cough in control guinea pigs, but not in those with airway sensory nerves desensitized by capsaicin. Coughs elicited by TRPA1 agonists were reduced by non-selective (camphor and gentamicin) and selective (HC-030031) TRPA1 antagonists, whereas they were unaffected by the TRPV1 antagonist, capsazepine. Acrolein and crotonaldehyde, two alpha,beta-unsaturated aldehydes recently identified as TRPA1 stimulants and contained in cigarette smoke, air pollution or produced endogenously by oxidative stress, caused a remarkable tussive effect, a response that was selectively inhibited by HC-030031. Part of the cough response induced by cigarette smoke inhalation was inhibited by HC-030031, suggesting the involvement of TRPA1. A novel pro-tussive pathway involves the TRPA1 channel, expressed by capsaicin-sensitive airway sensory nerves and is activated by a series of exogenous (cigarette smoke) and endogenous irritants. These results suggest TRPA1 may be a novel target for anti-tussive medicines.

Retinoids activate the irritant receptor TRPV1 and produce sensory hypersensitivity

PubMed Central

Yin, Shijin; Luo, Jialie; Qian, Aihua; Du, Junhui; Yang, Qing; Zhou, Shentai; Yu, Weihua; Du, Guangwei; Clark, Richard B.; Walters, Edgar T.; Carlton, Susan M.; Hu, Hongzhen

2013-01-01

Retinoids are structurally related derivatives of vitamin A and are required for normal vision as well as cell proliferation and differentiation. Clinically, retinoids are effective in treating many skin disorders and cancers. Application of retinoids evokes substantial irritating side effects, including pain and inflammation; however, the precise mechanisms accounting for the sensory hypersensitivity are not understood. Here we show that both naturally occurring and synthetic retinoids activate recombinant or native transient receptor potential channel vanilloid subtype 1 (TRPV1), an irritant receptor for capsaicin, the pungent ingredient of chili peppers. In vivo, retinoids produced pain-related behaviors that were either eliminated or significantly reduced by genetic or pharmacological inhibition of TRPV1 function. These findings identify TRPV1 as an ionotropic receptor for retinoids and provide cellular and molecular insights into retinoid-evoked hypersensitivity. These findings also suggest that selective TRPV1 antagonists are potential therapeutic drugs for treating retinoid-induced sensory hypersensitivity. PMID:23925292

TRPV2 in the development of experimental colitis.

PubMed

Issa, C M; Hambly, B D; Wang, Y; Maleki, S; Wang, W; Fei, J; Bao, S

2014-11-01

Colitis is still a significant disease challenge in humans, but its underlying mechanism remains to be fully elucidated. The transient receptor potential vanilloid (TRPV) ion channel plays an important pathological role in host immunity, as deficiency of TRPV compromises host defence in vivo and in vitro. Using a DSS-induced colitis mouse model, the function of TRPV2 in the development of colitis was investigated, utilizing TRPV2(-/-) and Wt mice. Less severe colitis was observed in TRPV2(-/-) , compared to that of Wt mice, at the clinical, histopathological and immunohistochemical levels. Compared to Wt mice, reduced severity of colitis in TRPV2(-/-) mice may be due to less intestinal inflammation via reduced recruitment of macrophages. The TRPV2 pathway contributes to the development of colitis. These data provide useful information for potential therapeutic intervention in colitis patients. © 2014 John Wiley & Sons Ltd.

The effects of cannabinoid CB1, CB2 and vanilloid TRPV1 receptor antagonists on cocaine addictive behavior in rats.

PubMed

Adamczyk, Przemysław; Miszkiel, Joanna; McCreary, Andrew C; Filip, Małgorzata; Papp, Mariusz; Przegaliński, Edmund

2012-03-20

There is evidence that indicates that tonic activation of cannabinoid CB1 receptors plays a role in extinction/reinstatement of cocaine seeking-behavior but is not involved in the maintenance of cocaine self-administration. To further explore the importance of other endocannabinoid-related receptors in an animal model of cocaine addiction, the present paper examines cannabinoid CB2 receptor antagonist N-((1S)-endo-1,3,3-trimethylbicyclo(2.2.1)heptan-2-yl)-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528) and the transient receptor potential vanilloid type-1 (TRPV1) receptor antagonist N-(3-methoxyphenyl)-4-chlorocinnamide (SB366791) on intravenous (i.v.) cocaine self-administration and extinction/reinstatement of cocaine-seeking behavior in rats. For comparison and reference purposes, the effect of the cannabinoid CB1 receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) was also examined. Moreover, for comparison effects of those drugs on operant lever responding for artificial (cocaine) vs. natural (food) reward, food self-administration was also evaluated. Our findings show that AM251 (1-3mg/kg), SR144528 (0.1-1mg/kg) and SB366791 (0.3-1mg/kg) did not affect cocaine self-administration. However, AM251 (0.1-1mg/kg), SR144528 (0.1-1mg/kg) and SB366791 (0.1-1mg/kg) decreased cocaine-induced reinstatement of cocaine-seeking behavior, and AM251 (0.3-1mg/kg) decreased cue-induced reinstatement. Moreover, AM251 (3mg/kg), SR144528 (0.1-1mg/kg) and SB366791 (0.1-1mg/kg) slightly decreased food self-administration behavior, but only AM251 (3mg/kg) reduced food reward. In conclusion, our results indicate for the first time, that tonic activation of CB2 or TRPV1 receptors is involved in cocaine-induced reinstatement of cocaine-seeking behavior, but their activity is not necessary for the rewarding effect of this psychostimulant. In contrast to CB1 receptors, neither CB2 nor TRPV1 receptors play a role in cue-induced reinstatement of cocaine-seeking behavior. Copyright © 2012 Elsevier B.V. All rights reserved.

TRPV3 in Drug Development

PubMed Central

Broad, Lisa M.; Mogg, Adrian J.; Eberle, Elizabeth; Tolley, Marcia; Li, Dominic L.; Knopp, Kelly L.

2016-01-01

Transient receptor potential vanilloid 3 (TRPV3) is a member of the TRP (Transient Receptor Potential) super-family. It is a relatively underexplored member of the thermo-TRP sub-family (Figure 1), however, genetic mutations and use of gene knock-outs and selective pharmacological tools are helping to provide insights into its role and therapeutic potential. TRPV3 is highly expressed in skin, where it is implicated in skin physiology and pathophysiology, thermo-sensing and nociception. Gain of function TRPV3 mutations in rodent and man have enabled the role of TRPV3 in skin health and disease to be particularly well defined. Pre-clinical studies provide some rationale to support development of TRPV3 antagonists for therapeutic application for the treatment of inflammatory skin conditions, itch and pain. However, to date, only one compound directed towards block of the TRPV3 receptor (GRC15300) has progressed into clinical trials. Currently, there are no known clinical trials in progress employing a TRPV3 antagonist. PMID:27618069

The neuroprotective properties of palmitoylethanolamine against oxidative stress in a neuronal cell line

PubMed Central

2009-01-01

Background N-acylethanolamines (NAEs) are lipids upregulated in response to cell and tissue injury and are involved in cytoprotection. Arachidonylethanolamide (AEA) is a well characterized NAE that is an endogenous ligand at cannabinoid and vanilloid receptors, but it exists in small quantities relative to other NAE types. The abundance of other NAE species, such as palmitoylethanolamine (PEA), together with their largely unknown function and receptors, has prompted us to examine the neuroprotective properties and mechanism of action of PEA. We hypothesized that PEA protects HT22 cells from oxidative stress and activates neuroprotective kinase signaling pathways. Results Indeed PEA protected HT22 cells from oxidative stress in part by mediating an increase in phosphorylated Akt (pAkt) and ERK1/2 immunoreactivity as well as pAkt nuclear translocation. These changes take place within a time frame consistent with neuroprotection. Furthermore, we determined that changes in pAkt immunoreactivity elicited by PEA were not mediated by activation of cannabinoid receptor type 2 (CB2), thus indicating a novel mechanism of action. These results establish a role for PEA as a neuroprotectant against oxidative stress, which occurs in a variety of neurodegenerative diseases. Conclusions The results from this study reveal that PEA protects HT22 cells from oxidative stress and alters the localization and expression levels of kinases known to be involved in neuroprotection by a novel mechanism. Overall, these results identify PEA as a neuroprotectant with potential as a possible therapeutic agent in neurodegenerative diseases involving oxidative stress. PMID:20003317

Multiple target of hAmylin on rat primary hippocampal neurons.

PubMed

Zhang, Nan; Yang, Shengchang; Wang, Chang; Zhang, Jianghua; Huo, Lifang; Cheng, Yiru; Wang, Chuan; Jia, Zhanfeng; Ren, Leiming; Kang, Lin; Zhang, Wei

2017-02-01

Alzheimer's disease (AD) and type II diabetes mellitus (DM2) are the most common aging-related diseases and are characterized by β-amyloid and amylin accumulation, respectively. Multiple studies have indicated a strong correlation between these two diseases. Amylin oligomerization in the brain appears to be a novel risk factor for developing AD. Although amylin aggregation has been demonstrated to induce cytotoxicity in neurons through altering Ca 2+ homeostasis, the underlying mechanisms have not been fully explored. In this study, we investigated the effects of amylin on rat hippocampal neurons using calcium imaging and whole-cell patch clamp recordings. We demonstrated that the amylin receptor antagonist AC187 abolished the Ca 2+ response induced by low concentrations of human amylin (hAmylin). However, the Ca 2+ response induced by higher concentrations of hAmylin was independent of the amylin receptor. This effect was dependent on extracellular Ca 2+ . Additionally, blockade of L-type Ca 2+ channels partially reduced hAmylin-induced Ca 2+ response. In whole-cell recordings, hAmylin depolarized the membrane potential. Moreover, application of the transient receptor potential (TRP) channel antagonist ruthenium red (RR) attenuated the hAmylin-induced increase in Ca 2+ . Single-cell RT-PCR demonstrated that transient receptor potential vanilloid 4 (TRPV4) mRNA was expressed in most of the hAmylin-responsive neurons. In addition, selective knockdown of TRPV4 channels inhibited the hAmylin-evoked Ca 2+ response. These results indicated that different concentrations of hAmylin act through different pathways. The amylin receptor mediates the excitatory effects of low concentrations of hAmylin. In contrast, for high concentrations of hAmylin, hAmylin aggregates precipitated on the neuronal membrane, activated TRPV4 channels and subsequently triggered membrane voltage-gated calcium channel opening followed by membrane depolarization. Therefore, our data suggest that TRPV4 is a key molecular mediator for the cytotoxic effects of hAmylin on hippocampal neurons. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endocannabinoid system acts as a regulator of immune homeostasis in the gut.

PubMed

Acharya, Nandini; Penukonda, Sasi; Shcheglova, Tatiana; Hagymasi, Adam T; Basu, Sreyashi; Srivastava, Pramod K

2017-05-09

Endogenous cannabinoids (endocannabinoids) are small molecules biosynthesized from membrane glycerophospholipid. Anandamide (AEA) is an endogenous intestinal cannabinoid that controls appetite and energy balance by engagement of the enteric nervous system through cannabinoid receptors. Here, we uncover a role for AEA and its receptor, cannabinoid receptor 2 (CB2), in the regulation of immune tolerance in the gut and the pancreas. This work demonstrates a major immunological role for an endocannabinoid. The pungent molecule capsaicin (CP) has a similar effect as AEA; however, CP acts by engagement of the vanilloid receptor TRPV1, causing local production of AEA, which acts through CB2. We show that the engagement of the cannabinoid/vanilloid receptors augments the number and immune suppressive function of the regulatory CX3CR1 hi macrophages (Mϕ), which express the highest levels of such receptors among the gut immune cells. Additionally, TRPV1 -/- or CB2 -/- mice have fewer CX3CR1 hi Mϕ in the gut. Treatment of mice with CP also leads to differentiation of a regulatory subset of CD4 + cells, the Tr1 cells, in an IL-27-dependent manner in vitro and in vivo. In a functional demonstration, tolerance elicited by engagement of TRPV1 can be transferred to naïve nonobese diabetic (NOD) mice [model of type 1 diabetes (T1D)] by transfer of CD4 + T cells. Further, oral administration of AEA to NOD mice provides protection from T1D. Our study unveils a role for the endocannabinoid system in maintaining immune homeostasis in the gut/pancreas and reveals a conversation between the nervous and immune systems using distinct receptors.

POMC neurons in heat: A link between warm temperatures and appetite suppression.

PubMed

Vicent, Maria A; Mook, Conor L; Carter, Matthew E

2018-05-01

When core body temperature increases, appetite and food consumption decline. A higher core body temperature can occur during exercise, during exposure to warm environmental temperatures, or during a fever, yet the mechanisms that link relatively warm temperatures to appetite suppression are unknown. A recent study in PLOS Biology demonstrates that neurons in the mouse hypothalamus that express pro-opiomelanocortin (POMC), a neural population well known to suppress food intake, also express a temperature-sensitive ion channel, transient receptor potential vanilloid 1 (TRPV1). Slight increases in body temperature cause a TRPV1-dependent increase in activity in POMC neurons, which suppresses feeding in mice. Taken together, this study suggests a novel mechanism linking body temperature and food-seeking behavior.

No Camphor Toxicity in Cambodian Infants

PubMed Central

Johnson, Casey R.; Porter, Samuel G.; Coats, Debra; Whitfield, Kyly C.; Mengkheang, Khin; Topazian, Mark D.; Fischer, Philip R.

2017-01-01

Thiamine deficiency and beriberi are prevalent in Cambodia, although most infants with nonspecific clinical symptoms of beriberi, including tachypnea, lack echocardiographic evidence diagnostic of the disease. Camphor activates transient receptor potential vanilloid 3 (TRPV3), a nonselective ion channel expressed in the medial preoptic nucleus of the hypothalamus and thought to be important for thermo-sensitivity. Because camphorated ointments are used commonly among Cambodian infants, we hypothesized that topical camphor modulates thermoregulatory behaviors, causing beriberi-simulating tachypnea, separate from any influence of thiamine deficiency. We assessed 9 tachypneic and 10 healthy infants for Tiger Balm use and for presence of camphor in whole blood. However, no camphor was found in blood from any infants, indicating that camphor is unrelated to tachypneic illness in Cambodian infants. PMID:28491925

TRPV1 Blocking Alleviates Airway Inflammation and Remodeling in a Chronic Asthma Murine Model.

PubMed

Choi, Joon Young; Lee, Hwa Young; Hur, Jung; Kim, Kyung Hoon; Kang, Ji Young; Rhee, Chin Kook; Lee, Sook Young

2018-05-01

Asthma is a chronic inflammatory airway disease characterized by airway hyperresponsiveness (AHR), inflammation, and remodeling. There is emerging interest in the involvement of the transient receptor potential vanilloid 1 (TRPV1) channel in the pathophysiology of asthma. This study examined whether TRPV1 antagonism alleviates asthma features in a murine model of chronic asthma. BALB/c mice were sensitized to and challenged by ovalbumin to develop chronic asthma. Capsazepine (TRPV1 antagonist) or TRPV1 small interfering RNA (siRNA) was administered in the treatment group to evaluate the effect of TPV1 antagonism on AHR, airway inflammation, and remodeling. The mice displayed increased AHR, airway inflammation, and remodeling. Treatment with capsazepine or TRPV1 siRNA reduced AHR to methacholine and airway inflammation. Type 2 T helper (Th2) cytokines (interleukin [IL]-4, IL-5, and IL-13) were reduced and epithelial cell-derived cytokines (thymic stromal lymphopoietin [TSLP], IL-33, and IL-25), which regulate Th2 cytokine-associated inflammation, were also reduced. Airway remodeling characterized by goblet cell hyperplasia, increased α-smooth muscle action, and collagen deposition was also alleviated by both treatments. Treatment directed at TRPV1 significantly alleviated AHR, airway inflammation, and remodeling in a chronic asthma murine model. The TRPV1 receptor can be a potential drug target for chronic bronchial asthma. Copyright © 2018 The Korean Academy of Asthma, Allergy and Clinical Immunology · The Korean Academy of Pediatric Allergy and Respiratory Disease.

Distribution and expression of non-neuronal transient receptor potential (TRPV) ion channels in rosacea.

PubMed

Sulk, Mathias; Seeliger, Stephan; Aubert, Jerome; Schwab, Verena D; Cevikbas, Ferda; Rivier, Michel; Nowak, Pawel; Voegel, Johannes J; Buddenkotte, Jörg; Steinhoff, Martin

2012-04-01

Rosacea is a frequent chronic inflammatory skin disease of unknown etiology. Because early rosacea reveals all characteristics of neurogenic inflammation, a central role of sensory nerves in its pathophysiology has been discussed. Neuroinflammatory mediators and their receptors involved in rosacea are poorly defined. Good candidates may be transient receptor potential (TRP) ion channels of vanilloid type (TRPV), which can be activated by many trigger factors of rosacea. Interestingly, TRPV2, TRPV3, and TRPV4 are expressed by both neuronal and non-neuronal cells. Here, we analyzed the expression and distribution of TRPV receptors in the various subtypes of rosacea on non-neuronal cells using immunohistochemistry, morphometry, double immunoflourescence, and quantitative real-time PCR (qRT-PCR) as compared with healthy skin and lupus erythematosus. Our results show that dermal immunolabeling of TRPV2 and TRPV3 and gene expression of TRPV1 is significantly increased in erythematotelangiectatic rosacea (ETR). Papulopustular rosacea (PPR) displayed an enhanced immunoreactivity for TRPV2, TRPV4, and also of TRPV2 gene expression. In phymatous rosacea (PhR)-affected skin, dermal immunostaining of TRPV3 and TRPV4 and gene expression of TRPV1 and TRPV3 was enhanced, whereas epidermal TRPV2 staining was decreased. Thus, dysregulation of TRPV channels also expressed by non-neuronal cells may be critically involved in the initiation and/or development of rosacea. TRP ion channels may be targets for the treatment of rosacea.

Distribution and Expression of Non-Neuronal Transient Receptor Potential (TRPV) Ion Channels in Rosacea

PubMed Central

Sulk, Mathias; Seeliger, Stephan; Aubert, Jerome; Schwab, Verena D.; Cevikbas, Ferda; Rivier, Michel; Nowak, Pawel; Voegel, Johannes J.; Buddenkotte, Jörg; Steinhoff, Martin

2011-01-01

Rosacea is a frequent chronic inflammatory skin disease of unknown etiology. Because early rosacea reveals all characteristics of neurogenic inflammation, a central role of sensory nerves in its pathophysiology has been discussed. Neuroinflammatory mediators and their receptors involved in rosacea are poorly defined. Good candidates may be transient receptor potential (TRP) ion channels of vanilloid type (TRPV), which can be activated by many trigger factors of rosacea. Interestingly, TRPV2, TRPV3, and TRPV4 are expressed by both neuronal and non-neuronal cells. Here, we analyzed the expression and distribution of TRPV receptors in the various subtypes of rosacea on non-neuronal cells using immunohistochemistry, morphometry, double immunoflourescence, and quantitative real-time PCR (qRT-PCR) as compared with healthy skin and lupus erythematosus. Our results show that dermal immunolabeling of TRPV2 and TRPV3 and gene expression of TRPV1 is significantly increased in erythematotelangiectatic rosacea (ETR). Papulopustular rosacea (PPR) displayed an enhanced immunoreactivity for TRPV2, TRPV4, and also of TRPV2 gene expression. In phymatous rosacea (PhR)-affected skin, dermal immunostaining of TRPV3 and TRPV4 and gene expression of TRPV1 and TRPV3 was enhanced, whereas epidermal TRPV2 staining was decreased. Thus, dysregulation of TRPV channels also expressed by non-neuronal cells may be critically involved in the initiation and/or development of rosacea. TRP ion channels may be targets for the treatment of rosacea. PMID:22189789

Modulation of transient receptor potential vanilloid 4-mediated membrane currents and synaptic transmission by protein kinase C

PubMed Central

Cao, De-Shou; Yu, Shuang-Quan; Premkumar, Louis S

2009-01-01

Background Transient receptor potential Vanilloid (TRPV) receptors are involved in nociception and are expressed predominantly in sensory neurons. TRPV1, a non-selective cation channel has been extensively studied and is responsible for inflammatory thermal hypersensitivity. In this study, the expression and function of TRPV4 have been characterized and compared with those of TRPV1. Results Immunohistochemical studies revealed that both TRPV1 and TRPV4 were co-expressed in dorsal root ganglion (DRG) neuronal cell bodies and in the central terminals of laminae I and II of the spinal dorsal horn (DH). In Ca2+ fluorescence imaging and whole-cell patch-clamp experiments, TRPV1- and TRPV4-mediated responses were observed in a population of the same DRG neurons. Sensitization of TRPV1 has been shown to be involved in inflammatory pain conditions. Incubation with phorbol 12, 13-dibutyrate (PDBu), a PKC activator, resulted in a significant potentiation of TRPV4 currents in DRG neurons. In TRPV4 expressing HEK 293T cells, PDBu increased 4α-phorbol 12, 13-didecanoate (4α-PDD)-induced single-channel activity in cell-attached patches, which was abrogated by bisindolylmaleimide (BIM), a selective PKC inhibitor. TRPV4 is also expressed at the central terminals of sensory neurons. Activation of TRPV4 by 4α-PDD increased the frequency of miniature excitatory post synaptic currents (mEPSCs) in DRG-DH neuronal co-cultures. 4α-PDD-induced increase in the frequency of mEPSCs was further enhanced by PDBu. The expression of TRP channels has been shown in other areas of the CNS; application of 4α-PDD significantly increased the mEPSC frequency in cultured hippocampal neurons, which was further potentiated by PDBu, whereas, TRPV1 agonist capsaicin did not modulate synaptic transmission. Conclusion These results indicate that TRPV4 and TRPV1 are co-expressed in certain DRG neurons and TRPV4 can be sensitized by PKC not only in DRG neuronal cell bodies, but also in the central sensory and non-sensory nerve terminals. Co-expression of TRPV1 and TRPV4 ion channels, their modulation of synaptic transmission and their sensitization by PKC may synergistically play a role in nociception. PMID:19208258

TRPV3 expression and vasodilator function in isolated uterine radial arteries from non-pregnant and pregnant rats.

PubMed

Murphy, Timothy V; Kanagarajah, Arjna; Toemoe, Sianne; Bertrand, Paul P; Grayson, T Hilton; Britton, Fiona C; Leader, Leo; Senadheera, Sevvandi; Sandow, Shaun L

2016-08-01

This study investigated the expression and function of transient receptor potential vanilloid type-3 ion channels (TRPV3) in uterine radial arteries isolated from non-pregnant and twenty-day pregnant rats. Immunohistochemistry (IHC) suggested TRPV3 is primarily localized to the smooth muscle in arteries from both non-pregnant and pregnant rats. IHC using C' targeted antibody, and qPCR of TRPV3 mRNA, suggested pregnancy increased arterial TRPV3 expression. The TRPV3 activator carvacrol caused endothelium-independent dilation of phenylephrine-constricted radial arteries, with no difference between vessels from non-pregnant and pregnant animals. Carvacrol-induced dilation was reduced by the TRPV3-blockers isopentenyl pyrophosphate and ruthenium red, but not by the TRPA1 or TRPV4 inhibitors HC-030031 or HC-067047, respectively. In radial arteries from non-pregnant rats only, inhibition of NOS and sGC, or PKG, enhanced carvacrol-mediated vasodilation. Carvacrol-induced dilation of arteries from both non-pregnant and pregnant rats was prevented by the IKCa blocker TRAM-34. TRPV3 caused an endothelium-independent, IKCa-mediated dilation of the uterine radial artery. NO-PKG-mediated modulation of TRPV3 activity is lost in pregnancy, but this did not alter the response to carvacrol. Copyright © 2016 Elsevier Inc. All rights reserved.

Application of amphipols for structure-functional analysis of TRP channels.

PubMed

Huynh, Kevin W; Cohen, Matthew R; Moiseenkova-Bell, Vera Y

2014-10-01

Amphipathic polymers (amphipols), such as A8-35 and SApol, are a new tool for stabilizing integral membrane proteins in detergent-free conditions for structural and functional studies. Transient receptor potential (TRP) ion channels function as tetrameric protein complexes in a diverse range of cellular processes including sensory transduction. Mammalian TRP channels share ~20 % sequence similarity and are categorized into six subfamilies: TRPC (canonical), TRPV (vanilloid), TRPA (ankyrin), TRPM (melastatin), TRPP (polycystin), and TRPML (mucolipin). Due to the inherent difficulties in purifying eukaryotic membrane proteins, structural studies of TRP channels have been limited. Recently, A8-35 was essential in resolving the molecular architecture of the nociceptor TRPA1 and led to the determination of a high-resolution structure of the thermosensitive TRPV1 channel by cryo-EM. Newly developed maltose-neopentyl glycol (MNG) detergents have also proven to be useful in stabilizing TRP channels for structural analysis. In this review, we will discuss the impacts of amphipols and MNG detergents on structural studies of TRP channels by cryo-EM. We will compare how A8-35 and MNG detergents interact with the hydrophobic transmembrane domains of TRP channels. In addition, we will discuss what these cryo-EM studies reveal on the importance of screening different types of surfactants toward determining high-resolution structures of TRP channels.

Application of amphipols for structure-functional analysis of TRP channels

PubMed Central

Huynh, Kevin W.; Cohen, Matthew R.; Moiseenkova-Bell, Vera Y.

2014-01-01

Amphipathic polymers (amphipols), such as A8-35 and SApol, are a new tool for stabilizing integral membrane proteins in detergent-free conditions for structural and functional studies. Transient receptor potential (TRP) ion channels function as tetrameric protein complexes in a diverse range of cellular processes including sensory transduction. Mammalian TRP channels share ~20% sequence similarity and are categorized into six subfamilies: TRPC (canonical), TRPV (vanilloid), TRPA (ankyrin), TRPM (melastatin), TRPP (polycystin), and TRPML (mucolipin). Due to the inherent difficulties in purifying eukaryotic membrane proteins, structural studies of TRP channels have been limited. Recently, A8-35 was essential in resolving the molecular architecture of the nociceptor TRPA1 and led to the determination of a high resolution structure of the thermosensitive TRPV1 channel by cryo-EM. Newly developed maltose-neopentyl glycol (MNG) detergents have also proven useful in stabilizing TRP channels for structural analysis. In this review, we will discuss the impact of amphipols and MNG detergents on structural studies of TRP channels by cryo-EM. We will compare how A8-35 and MNG detergents interact with the hydrophobic transmembrane (TM) domains of TRP channels. In addition, we will discuss what these cryo-EM studies reveal on the importance of screening different types of surfactants towards determining high resolution structures of TRP channels. PMID:24894720

TRPV1 variants impair intracellular Ca2+ signaling and may confer susceptibility to malignant hyperthermia.

PubMed

Abeele, Fabien Vanden; Lotteau, Sabine; Ducreux, Sylvie; Dubois, Charlotte; Monnier, Nicole; Hanna, Amy; Gkika, Dimitra; Romestaing, Caroline; Noyer, Lucile; Flourakis, Matthieu; Tessier, Nolwenn; Al-Mawla, Ribal; Chouabe, Christophe; Lefai, Etienne; Lunardi, Joël; Hamilton, Susan; Fauré, Julien; Van Coppenolle, Fabien; Prevarskaya, Natalia

2018-06-21

Malignant hyperthermia (MH) is a pharmacogenetic disorder arising from uncontrolled muscle calcium release due to an abnormality in the sarcoplasmic reticulum (SR) calcium-release mechanism triggered by halogenated inhalational anesthetics. However, the molecular mechanisms involved are still incomplete. We aimed to identify transient receptor potential vanilloid 1 (TRPV1) variants within the entire coding sequence in patients who developed sensitivity to MH of unknown etiology. In vitro and in vivo functional studies were performed in heterologous expression system, trpv1 -/- mice, and a murine model of human MH. We identified TRPV1 variants in two patients and their heterologous expression in muscles of trpv1 -/- mice strongly enhanced calcium release from SR upon halogenated anesthetic stimulation, suggesting they could be responsible for the MH phenotype. We confirmed the in vivo significance by using mice with a knock-in mutation (Y524S) in the type I ryanodine receptor (Ryr1), a mutation analogous to the Y522S mutation associated with MH in humans. We showed that the TRPV1 antagonist capsazepine slows the heat-induced hypermetabolic response in this model. We propose that TRPV1 contributes to MH and could represent an actionable therapeutic target for prevention of the pathology and also be responsible for MH sensitivity when mutated.

An endogenous capsaicin-like substance with high potency at recombinant and native vanilloid VR1 receptors

PubMed Central

Huang, Susan M.; Bisogno, Tiziana; Trevisani, Marcello; Al-Hayani, Abdulmonem; De Petrocellis, Luciano; Fezza, Filomena; Tognetto, Michele; Petros, Timothy J.; Krey, Jocelyn F.; Chu, Constance J.; Miller, Jeffrey D.; Davies, Stephen N.; Geppetti, Pierangelo; Walker, J. Michael; Di Marzo, Vincenzo

2002-01-01

The vanilloid receptor VR1 is a nonselective cation channel that is most abundant in peripheral sensory fibers but also is found in several brain nuclei. VR1 is gated by protons, heat, and the pungent ingredient of “hot” chili peppers, capsaicin. To date, no endogenous compound with potency at this receptor comparable to that of capsaicin has been identified. Here we examined the hypothesis, based on previous structure-activity relationship studies and the availability of biosynthetic precursors, that N-arachidonoyl-dopamine (NADA) is an endogenous “capsaicin-like” substance in mammalian nervous tissues. We found that NADA occurs in nervous tissues, with the highest concentrations being found in the striatum, hippocampus, and cerebellum and the lowest concentrations in the dorsal root ganglion. We also gained evidence for the existence of two possible routes for NADA biosynthesis and mechanisms for its inactivation in rat brain. NADA activates both human and rat VR1 overexpressed in human embryonic kidney (HEK)293 cells, with potency (EC50 ≈ 50 nM) and efficacy similar to those of capsaicin. Furthermore, NADA potently activates native vanilloid receptors in neurons from rat dorsal root ganglion and hippocampus, thereby inducing the release of substance P and calcitonin gene-related peptide (CGRP) from dorsal spinal cord slices and enhancing hippocampal paired-pulse depression, respectively. Intradermal NADA also induces VR1-mediated thermal hyperalgesia (EC50 = 1.5 ± 0.3 μg). Our data demonstrate the existence of a brain substance similar to capsaicin not only with respect to its chemical structure but also to its potency at VR1 receptors. PMID:12060783

Expression of transient receptor potential vanilloid 1 (TRPV1) and 2 (TRPV2) in human peripheral blood.

PubMed

Saunders, Cassandra Im; Kunde, Dale A; Crawford, Amanda; Geraghty, Dominic P

2007-02-01

The vanilloid receptor family of cation channels includes the capsaicin-sensitive, proton- and heat-activated TRPV1 and noxious heat-activated TRPV2. The present study demonstrates both gene and protein expression of TRPV1 and TRPV2 in human peripheral blood cells (PBCs) using molecular and immunocytochemical techniques. Using reverse-transcription polymerase chain reaction (RT-PCR) and quantitative real-time RT-PCR (qRT-PCR), TRPV1 and TRPV2 mRNA was detected in mRNA isolated from human whole peripheral blood. Using qRT-PCR, TRPV2 mRNA was highly expressed in human whole blood isolates (9.33+/-1.19 x 10(4)copies per 10(6)copies of the housekeeping gene GAPDH), whereas TRPV1 message was detected at approximately 150-fold lower levels (638+/-121 copies per 10(6)copies GAPDH). At the protein level, TRPV1 and TRPV2 activity was determined immunocytochemically in a lymphocyte-enriched mononuclear cell preparation (83+/-2% lymphocytes). Cells were labelled with rabbit anti-TRPV1 or goat anti-TRPV2 (1:500) and subsequently labelled with goat Texas red- (TRPV1) or FITC-(TRPV2) conjugated secondary antibodies (1:1000). All cells demonstrated punctate TRPV1-immunoreactivity, which appeared to be on the plasma membrane and in the cytoplasm. In contrast, cells within subjects appeared to express the TRPV1 protein at varying intensities. TRPV2-immunoreactivity appeared diffuse. This is the first study to demonstrate the presence of both TRPV1 and TRPV2 in human peripheral lymphocytes. Further studies need to be undertaken in order to determine the role of TRPV channels in these cells.

Effects of fatty acid amide hydrolase (FAAH) inhibitors on working memory in rats.

PubMed

Panlilio, Leigh V; Thorndike, Eric B; Nikas, Spyros P; Alapafuja, Shakiru O; Bandiera, Tiziano; Cravatt, Benjamin F; Makriyannis, Alexandros; Piomelli, Daniele; Goldberg, Steven R; Justinova, Zuzana

2016-05-01

Manipulations of the endocannabinoid system could potentially produce therapeutic effects with minimal risk of adverse cannabis-like side effects. Inhibitors of fatty acid amide hydrolase (FAAH) increase endogenous levels of the cannabinoid-receptor agonist, anandamide, and show promise for treating a wide range of disorders. However, their effects on learning and memory have not been fully characterized. We determined the effects of five structurally different FAAH inhibitors in an animal model of working memory known to be sensitive to impairment by delta-9 tetrahydrocannabinol (THC). A delayed nonmatching-to-position procedure was used in rats. Illuminated nosepoke holes were used to provide sample cues (left versus right) and record responses (correct versus incorrect) after delays ranging from 0 to 28 s. Various test drugs were given acutely up to two times per week before daily sessions. One FAAH inhibitor, AM3506 (3 mg/kg), decreased accuracy in the memory task. Four other FAAH inhibitors (URB597, URB694, PF-04457845, and ARN14633) and a monoacylglycerol lipase inhibitor (JZL184, which blocks the degradation of the endocannabinoid 2-arachidonoylglycerol) had no effect. Testing of AM3506 in combination with antagonists for receptors known to be affected by anandamide and other fatty acid amides indicated that the impairment induced by AM3506 was mediated by cannabinoid CB1 receptors, and not by alpha-type peroxisome proliferator-activated receptors (PPAR-alpha) or vanilloid transient receptor potential cation channels (TRPV1). FAAH inhibitors differ with respect to their potential for memory impairment, abuse liability, and probably other cannabis-like effects, and they should be evaluated individually for specific therapeutic and adverse effects.

Effects of fatty acid amide hydrolase (FAAH) inhibitors on working memory in rats

PubMed Central

Panlilio, Leigh V.; Thorndike, Eric B.; Nikas, Spyros P.; Alapafuja, Shakiru O.; Bandiera, Tiziano; Cravatt, Benjamin F.; Makriyannis, Alexandros; Piomelli, Daniele; Goldberg, Steven R.; Justinova, Zuzana

2015-01-01

Rationale Manipulations of the endocannabinoid system could potentially produce therapeutic effects with minimal risk of adverse cannabis-like side effects. Inhibitors of fatty acid amide hydrolase (FAAH) increase endogenous levels of the cannabinoid-receptor agonist, anandamide, and show promise for treating a wide range of disorders. However, their effects on learning and memory have not been fully characterized. Objectives We determined the effects of five structurally different FAAH inhibitors in an animal model of working memory known to be sensitive to impairment by delta-9 tetrahydrocannabinol (THC). Methods A delayed nonmatching-to-position procedure was used in rats. Illuminated nosepoke holes were used to provide sample cues (left versus right) and record responses (correct versus incorrect) after delays ranging from 0-28 seconds. Various test drugs were given acutely up to two times per week before daily sessions. Results One FAAH inhibitor, AM3506 (3 mg/kg), decreased accuracy in the memory task. Four other FAAH inhibitors (URB597, URB694, PF-04457845, and ARN14633) and a monoacylglycerol lipase inhibitor (JZL184, which blocks the degradation of the endocannabinoid 2-arachidonoylglycerol) had no effect. Testing of AM3506 in combination with antagonists for receptors known to be affected by anandamide and other fatty-acid amides indicated that the impairment induced by AM3506 was mediated by cannabinoid CB1 receptors, and not by alpha-type peroxisome proliferator-activated receptors (PPAR-alpha) or vanilloid transient receptor potential cation channels (TRPV1). Conclusions FAAH inhibitors differ with respect to their potential for memory impairment, abuse liability, and probably other cannabis-like effects, and they should be evaluated individually for specific therapeutic and adverse effects. PMID:26558620

Abdominal pain and the neurotrophic system in ulcerative colitis.

PubMed

Deberry, Jennifer J; Bielefeldt, Klaus; Davis, Brian M; Szigethy, Eva M; Hartman, Douglas J; Coates, Matthew D

2014-12-01

We undertook a study to test the hypothesis that inflammation alters peripheral sensory mechanisms, thereby contributing to chronic abdominal pain in ulcerative colitis (UC). Patients with UC and healthy individuals rated abdominal pain using a visual analog scale and completed surveys describing anxiety or depression (Hospital Anxiety and Depression Score) and gastrointestinal symptoms (Rome III questionnaire). Patient age, sex, and severity of inflammation were determined. Rectal biopsies were processed using immunohistochemical techniques to assess nerve fiber density and real-time PCR to determine transcript expression of neurotrophins (nerve growth factor, glial cell-derived neurotrophic factor, artemin, neurturin), ion channels (transient receptor potential vanilloid type 1, transient receptor potential ankyrin 1) and inflammatory mediators (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, IL-10, IL-17). A total of 77 patients with UC (27 female, 50 male) and 21 controls (10 female, 11 male) were enrolled. Patients with UC with pain had significantly higher depression scores than controls and patients with UC without pain (P < 0.05). There was no correlation between any of the inflammatory markers and pain scores. Visual analog scale pain scores significantly correlated with younger age, higher depression scores, increased expression of neurturin and decreased expression of transient receptor potential ankyrin 1 in the mucosa. Mucosal nerve fiber density did not correlate with any measures of inflammation or pain. Only higher depression scores independently predicted pain in UC (r > 0.5). We did not observe changes in mucosal innervation and did not see a significant relationship between nerve fiber density, inflammatory mediators, neurotrophic factors, or mucosal ion channel expression and pain. In contrast, the importance of depression as the only independent predictor of pain ratings mirrors functional disorders, where central processes significantly contribute to symptom development and/or perpetuation.

Citral: a monoterpene with prophylactic and therapeutic anti-nociceptive effects in experimental models of acute and chronic pain.

PubMed

Nishijima, Catarine M; Ganev, Ellen G; Mazzardo-Martins, Leidiane; Martins, Daniel F; Rocha, Lúcia R M; Santos, Adair R S; Hiruma-Lima, Clelia A

2014-08-05

Citral (3,7-dimethyl-2,6-octadienal) is an open-chain monoterpenoid present in the essential oils of several medicinal plants. The aim of this work was to evaluate the effects of orally administered citral in experimental models of acute and chronic nociception, inflammation, and gastric ulcers caused by non-steroidal anti-inflammatory drugs (NSAIDs). Oral treatment with citral significantly inhibited the neurogenic and inflammatory pain responses induced by intra-plantar injection of formalin. Citral also had prophylactic and therapeutic anti-nociceptive effects against mechanical hyperalgesia in plantar incision surgery, chronic regional pain syndrome, and partial ligation of sciatic nerve models, without producing any significant motor dysfunction. In addition, citral markedly attenuated the pain response induced by intra-plantar injection of glutamate and phorbol 12-myristate 13-acetate (PMA, a protein kinase C activator), as well as by intrathecal (i.t.) injection of ionotropic and metabotropic glutamate receptor agonists (N-methyl-D-aspartic acid [NMDA] and 1-amino-1,3-dicarboxycyclopentane [trans-ACPD], respectively), substance P, and cytokine tumour necrosis factor-α. However, citral potentiated behaviours indicative of pain caused by i.t., but not intra-plantar, injection of a transient receptor potential vanilloid receptor type 1 (TRPV1) agonist. Finally, the anti-nociceptive action of citral was found to involve significant activation of the 5-HT2A serotonin receptor. The effect of citral was accompanied by a gastro-protective effect against NSAID-induced ulcers. Together, these results show the potential of citral as a new drug for the treatment of pain. Copyright © 2014 Elsevier B.V. All rights reserved.

Mechanisms underlying capsaicin effects in canine coronary artery: implications for coronary spasm

PubMed Central

Hiett, S. Christopher; Owen, Meredith K.; Li, Wennan; Chen, Xingjuan; Riley, Ashley; Noblet, Jillian; Flores, Sarah; Sturek, Michael; Tune, Johnathan D.; Obukhov, Alexander G.

2014-01-01

Aims The TRPV1, transient receptor potential vanilloid type 1, agonist capsaicin is considered to be beneficial for cardiovascular health because it dilates coronary arteries through an endothelial-dependent mechanism and may slow atheroma progression. However, recent reports indicate that high doses of capsaicin may constrict coronary arterioles and even provoke myocardial infarction. Thus far, the mechanisms by which TRPV1 activation modulates coronary vascular tone remain poorly understood. This investigation examined whether there is a synergistic interplay between locally acting vasoconstrictive pro-inflammatory hormones (autacoids) and capsaicin effects in the coronary circulation. Methods and results Experiments were performed in canine conduit coronary artery rings and isolated smooth muscle cells (CASMCs). Isometric tension measurements revealed that 1–10 μM capsaicin alone did not affect resting tension of coronary artery rings. In contrast, in endothelium-intact rings pre-contracted with a Gq/11-coupled FP/TP (prostaglandin F/thromboxane) receptor agonist, prostaglandin F2α (PGF2α; 10 μM), capsaicin first induced transient dilation that was followed by sustained contraction. In endothelium-denuded rings pre-contracted with PGF2α or thromboxane analogue U46619 (1 μM, a TP receptor agonist), capsaicin induced only sustained contraction. Blockers of the TP receptor or TRPV1 significantly inhibited capsaicin effects, but these were still observed in the presence of 50 μM nifedipine and 70 mM KCl. Capsaicin also potentiated 20 mM KCl-induced contractions. Fluorescence imaging experiments in CASMCs revealed that the Gq/11-phospholipase C (PLC)-protein kinase C (PKC) and Ca2+-PLC-PKC pathways are likely involved in sensitizing CASMC TRPV1 channels. Conclusion Capsaicin alone does not cause contractions in conduit canine coronary artery; however, pre-treatment with pro-inflammatory prostaglandin–thromboxane agonists may unmask capsaicin's vasoconstrictive potential. PMID:24935430

Pain and beyond: fatty acid amides and fatty acid amide hydrolase inhibitors in cardiovascular and metabolic diseases.

PubMed

Pillarisetti, Sivaram; Alexander, Christopher W; Khanna, Ish

2009-12-01

Fatty acid amide hydrolase (FAAH) is responsible for the hydrolysis of several important endogenous fatty acid amides (FAAs), including anandamide, oleoylethanolamide and palmitoylethanolamide. Because specific FAAs interact with cannabinoid and vanilloid receptors, they are often referred to as 'endocannabinoids' or 'endovanilloids'. Initial interest in this area, therefore, has focused on developing FAAH inhibitors to augment the actions of FAAs and reduce pain. However, recent literature has shown that these FAAs - through interactions with unique receptors (extracellular and intracellular) - can induce a diverse array of effects that include appetite suppression, modulation of lipid and glucose metabolism, vasodilation, cardiac function and inflammation. This review gives an overview of FAAs and diverse FAAH inhibitors and their potential therapeutic utility in pain and non-pain indications.

Effect of Maillard Reacted Peptides on Human Salt Taste and the Amiloride-Insensitive Salt Taste Receptor (TRPV1t)

PubMed Central

Katsumata, Tadayoshi; Nakakuki, Hiroko; Tokunaga, Chikara; Fujii, Noboru; Egi, Makoto; Phan, Tam-Hao T.; Mummalaneni, Shobha; DeSimone, John A.

2008-01-01

Maillard reacted peptides (MRPs) were synthesized by conjugating a peptide fraction (1000–5000 Da) purified from soy protein hydrolyzate with galacturonic acid, glucosamine, xylose, fructose, or glucose. The effect of MRPs was investigated on human salt taste and on the chorda tympani (CT) taste nerve responses to NaCl in Sprague–Dawley rats, wild-type, and transient receptor potential vanilloid 1 (TRPV1) knockout mice. MRPs produced a biphasic effect on human salt taste perception and on the CT responses in rats and wild-type mice in the presence of NaCl + benzamil (Bz, a blocker of epithelial Na+ channels), enhancing the NaCl response at low concentrations and suppressing it at high concentrations. The effectiveness of MRPs as salt taste enhancers varied with the conjugated sugar moiety: galacturonic acid = glucosamine > xylose > fructose > glucose. The concentrations at which MRPs enhanced human salt taste were significantly lower than the concentrations of MRPs that produced increase in the NaCl CT response. Elevated temperature, resiniferatoxin, capsaicin, and ethanol produced additive effects on the NaCl CT responses in the presence of MRPs. Elevated temperature and ethanol also enhanced human salt taste perception. N-(3-methoxyphenyl)-4-chlorocinnamid (a blocker of TRPV1t) inhibited the Bz-insensitive NaCl CT responses in the absence and presence of MRPs. TRPV1 knockout mice demonstrated no Bz-insensitive NaCl CT response in the absence or presence of MRPs. The results suggest that MRPs modulate human salt taste and the NaCl + Bz CT responses by interacting with TRPV1t. PMID:18603652

Medial prefrontal cortex TRPV1 and CB1 receptors modulate cardiac baroreflex activity by regulating the NMDA receptor/nitric oxide pathway.

PubMed

Lagatta, Davi C; Kuntze, Luciana B; Ferreira-Junior, Nilson C; Resstel, Leonardo B M

2018-05-29

The ventral medial prefrontal cortex (vMPFC) facilitates the cardiac baroreflex response through N-methyl-D-aspartate (NMDA) receptor activation and nitric oxide (NO) formation by neuronal NO synthase (nNOS) and soluble guanylate cyclase (sGC) triggering. Glutamatergic transmission is modulated by the cannabinoid receptor type 1 (CB 1 ) and transient receptor potential vanilloid type 1 (TRPV 1 ) receptors, which may inhibit or stimulate glutamate release in the brain, respectively. Interestingly, vMPFC CB 1 receptors decrease cardiac baroreflex responses, while TRPV 1 channels facilitate them. Therefore, the hypothesis of the present study is that the vMPFC NMDA/NO pathway is regulated by both CB 1 and TRPV 1 receptors in the modulation of cardiac baroreflex activity. In order to test this assumption, we used male Wistar rats that had stainless steel guide cannulae bilaterally implanted in the vMPFC. Subsequently, a catheter was inserted into the femoral artery, for cardiovascular recordings, and into the femoral vein for assessing baroreflex activation. The increase in tachycardic and bradycardic responses observed after the microinjection of a CB 1 receptors antagonist into the vMPFC was prevented by an NMDA antagonist as well as by the nNOS and sGC inhibition. NO extracellular scavenging also abolished these responses. These same pharmacological manipulations inhibited cardiac reflex enhancement induced by TRPV 1 agonist injection into the area. Based on these results, we conclude that vMPFC CB 1 and TRPV 1 receptors inhibit or facilitate the cardiac baroreflex activity by stimulating or blocking the NMDA activation and NO synthesis.

Non-psychoactive cannabinoids modulate the descending pathway of antinociception in anaesthetized rats through several mechanisms of action

PubMed Central

Maione, Sabatino; Piscitelli, Fabiana; Gatta, Luisa; Vita, Daniela; De Petrocellis, Luciano; Palazzo, Enza; de Novellis, Vito; Di Marzo, Vincenzo

2011-01-01

BACKGROUND AND PURPOSE Two non-psychoactive cannabinoids, cannabidiol (CBD) and cannabichromene (CBC), are known to modulate in vitro the activity of proteins involved in nociceptive mechanisms, including transient receptor potential (TRP) channels of vanilloid type-1 (TRPV1) and of ankyrin type-1 (TRPA1), the equilibrative nucleoside transporter and proteins facilitating endocannabinoid inactivation. Here we have tested these two cannabinoids on the activity of the descending pathway of antinociception. EXPERIMENTAL APPROACH Electrical activity of ON and OFF neurons of the rostral ventromedial medulla in anaesthetized rats was recorded extracellularly and tail flick latencies to thermal stimuli were measured. CBD or CBC along with various antagonists were injected into the ventrolateral periaqueductal grey. KEY RESULTS Cannabidiol and CBC dose-dependently reduced the ongoing activity of ON and OFF neurons in anaesthetized rats, whilst inducing antinociceptive responses in the tail flick-test. These effects were maximal with 3 nmol CBD and 6 nmol CBC, and were antagonized by selective antagonists of cannabinoid CB1 adenosine A1 and TRPA1, but not of TRPV1, receptors. Both CBC and CBD also significantly elevated endocannabinoid levels in the ventrolateral periaqueductal grey. A specific agonist at TRPA1 channels and a synthetic inhibitor of endocannabinoid cellular reuptake exerted effects similar to those of CBC and CBD. CONCLUSIONS AND IMPLICATIONS CBD and CBC stimulated descending pathways of antinociception and caused analgesia by interacting with several target proteins involved in nociceptive control. These compounds might represent useful therapeutic agents with multiple mechanisms of action. PMID:20942863

Endocannabinoids in cerebrovascular regulation

PubMed Central

Ruisanchez, Éva; Leszl-Ishiguro, Miriam; Sándor, Péter; Pacher, Pál

2016-01-01

The cerebral blood flow is tightly regulated by myogenic, endothelial, metabolic, and neural mechanisms under physiological conditions, and a large body of recent evidence indicates that inflammatory pathways have a major influence on the cerebral blood perfusion in certain central nervous system disorders, like hemorrhagic and ischemic stroke, traumatic brain injury, and vascular dementia. All major cell types involved in cerebrovascular control pathways (i.e., smooth muscle, endothelium, neurons, astrocytes, pericytes, microglia, and leukocytes) are capable of synthesizing endocannabinoids and/or express some or several of their target proteins [i.e., the cannabinoid 1 and 2 (CB1 and CB2) receptors and the transient receptor potential vanilloid type 1 ion channel]. Therefore, the endocannabinoid system may importantly modulate the regulation of cerebral circulation under physiological and pathophysiological conditions in a very complex manner. Experimental data accumulated since the late 1990s indicate that the direct effect of cannabinoids on cerebral vessels is vasodilation mediated, at least in part, by CB1 receptors. Cannabinoid-induced cerebrovascular relaxation involves both a direct inhibition of smooth muscle contractility and a release of vasodilator mediator(s) from the endothelium. However, under stress conditions (e.g., in conscious restrained animals or during hypoxia and hypercapnia), cannabinoid receptor activation was shown to induce a reduction of the cerebral blood flow, probably via inhibition of the electrical and/or metabolic activity of neurons. Finally, in certain cerebrovascular pathologies (e.g., subarachnoid hemorrhage, as well as traumatic and ischemic brain injury), activation of CB2 (and probably yet unidentified non-CB1/non-CB2) receptors appear to improve the blood perfusion of the brain via attenuating vascular inflammation. PMID:26825517

Endocannabinoids in cerebrovascular regulation.

PubMed

Benyó, Zoltán; Ruisanchez, Éva; Leszl-Ishiguro, Miriam; Sándor, Péter; Pacher, Pál

2016-04-01

The cerebral blood flow is tightly regulated by myogenic, endothelial, metabolic, and neural mechanisms under physiological conditions, and a large body of recent evidence indicates that inflammatory pathways have a major influence on the cerebral blood perfusion in certain central nervous system disorders, like hemorrhagic and ischemic stroke, traumatic brain injury, and vascular dementia. All major cell types involved in cerebrovascular control pathways (i.e., smooth muscle, endothelium, neurons, astrocytes, pericytes, microglia, and leukocytes) are capable of synthesizing endocannabinoids and/or express some or several of their target proteins [i.e., the cannabinoid 1 and 2 (CB1 and CB2) receptors and the transient receptor potential vanilloid type 1 ion channel]. Therefore, the endocannabinoid system may importantly modulate the regulation of cerebral circulation under physiological and pathophysiological conditions in a very complex manner. Experimental data accumulated since the late 1990s indicate that the direct effect of cannabinoids on cerebral vessels is vasodilation mediated, at least in part, by CB1 receptors. Cannabinoid-induced cerebrovascular relaxation involves both a direct inhibition of smooth muscle contractility and a release of vasodilator mediator(s) from the endothelium. However, under stress conditions (e.g., in conscious restrained animals or during hypoxia and hypercapnia), cannabinoid receptor activation was shown to induce a reduction of the cerebral blood flow, probably via inhibition of the electrical and/or metabolic activity of neurons. Finally, in certain cerebrovascular pathologies (e.g., subarachnoid hemorrhage, as well as traumatic and ischemic brain injury), activation of CB2 (and probably yet unidentified non-CB1/non-CB2) receptors appear to improve the blood perfusion of the brain via attenuating vascular inflammation.

Cough reflex testing with inhaled capsaicin and TRPV1 activation in asthma and comorbid conditions.

PubMed

Couto, M; de Diego, A; Perpiñi, M; Delgado, L; Moreira, A

2013-01-01

A high parasympathetic tone leading to bronchoconstriction and neurogenic inflammation is thought to have a major role in the pathogenesis of asthma. Transient receptor potential vanilloid 1 (TRPV1) is the hub of almost all neuronal inflammatory signaling pathways. A critical determinant of neurogenic inflammation, TRPV1 functions as a sensor for detecting irritants in the lung by transmitting noxious stimuli to the central nervous system and inducing the release of a variety of proinflammatory neuropeptides at the peripheral terminals. Challenge with inhaled capsaicin, an exogenous agonist of TRPV1, has been used to measure the sensitivity of the cough reflex. However, inhalation of capsaicin is also associated with parasympathetic bronchoconstriction, mucus hypersecretion, vasodilatation, and the sensation of dyspnea. Therefore, inhaled capsaicin challenge is expected to have other potential applications in asthma and comorbid conditions, such as rhinitis and gastroesophageal reflux disease, both of which produce cough. Capsaicin challenge has established itself as a useful objective method for evaluating airway hypersensitivity; however, it is potentially valuable in many other situations, which will be reviewed in this paper.

Effect of TRPV2 cation channels on the proliferation, migration and invasion of 5637 bladder cancer cells.

PubMed

Liu, Quanliang; Wang, Xinghuan

2013-11-01

Transient receptor potential vanilloid 2 (TRPV2), a nonselective cation channel, has become an attractive target gene for tumor studies due to its wide range of physiological and pathological functions. However, its specific role in bladder cancer development and progression remains unclear. The aim of the present study was to investigate the effects of TRPV2 on the proliferation, migration and invasion of 5637 bladder cancer cells in vitro . Rat TRPV2 cDNA was transfected into 5637 bladder cancer cells and changes in the behavior of the cells were detected. It was observed that TRPV2 enhanced bladder cancer cell migration and invasion; however, it did not affect cell proliferation in vitro . TRPV2 activity, which may be mediated by direct matrix metalloproteinase 2 (MMP2) regulation, is important in bladder tumor development and progression. The results of this study suggest that TRPV2 channels are a potential therapeutic target for bladder carcinoma.

Effect of TRPV2 cation channels on the proliferation, migration and invasion of 5637 bladder cancer cells

PubMed Central

LIU, QUANLIANG; WANG, XINGHUAN

2013-01-01

Transient receptor potential vanilloid 2 (TRPV2), a nonselective cation channel, has become an attractive target gene for tumor studies due to its wide range of physiological and pathological functions. However, its specific role in bladder cancer development and progression remains unclear. The aim of the present study was to investigate the effects of TRPV2 on the proliferation, migration and invasion of 5637 bladder cancer cells in vitro. Rat TRPV2 cDNA was transfected into 5637 bladder cancer cells and changes in the behavior of the cells were detected. It was observed that TRPV2 enhanced bladder cancer cell migration and invasion; however, it did not affect cell proliferation in vitro. TRPV2 activity, which may be mediated by direct matrix metalloproteinase 2 (MMP2) regulation, is important in bladder tumor development and progression. The results of this study suggest that TRPV2 channels are a potential therapeutic target for bladder carcinoma. PMID:24223658

Temperature- and touch-sensitive neurons couple CNG and TRPV channel activities to control heat avoidance in Caenorhabditis elegans.

PubMed

Liu, Shu; Schulze, Ekkehard; Baumeister, Ralf

2012-01-01

Any organism depends on its ability to sense temperature and avoid noxious heat. The nematode Caenorhabditis elegans responds to noxious temperatures exceeding ∼35°C and also senses changes in its environmental temperature in the range between 15 and 25°C. The neural circuits and molecular mechanisms involved in thermotaxis have been successfully studied, whereas details of the thermal avoidance behavior remain elusive. In this work, we investigate neurological and molecular aspects of thermonociception using genetic, cell biological and physiological approaches. We show here that the thermosensory neurons AFD, in addition to sensing temperature within the range within which the animals can thrive, also contribute to the sensation of noxious temperatures resulting in a reflex-like escape reaction. Distinct sets of interneurons are involved in transmitting thermonociception and thermotaxis, respectively. Loss of AFD is partially compensated by the activity of a pair of multidendritic, polymodal neurons, FLP, whereas laser ablation of both types of neurons abrogated the heat response in the head of the animals almost completely. A third pair of heat sensory neurons, PHC, is situated in the tail. We find that the thermal avoidance response requires the cell autonomous function of cGMP dependent Cyclic Nucleotide-Gated (CNG) channels in AFD, and the heat- and capsaicin-sensitive Transient Receptor Potential Vanilloid (TRPV) channels in the FLP and PHC sensory neurons. Our results identify distinct thermal responses mediated by a single neuron, but also show that parallel nociceptor circuits and molecules may be used as back-up strategies to guarantee fast and efficient responses to potentially detrimental stimuli.

PI3-kinase promotes TRPV2 activity independently of channel translocation to the plasma membrane.

PubMed

Penna, Aubin; Juvin, Véronique; Chemin, Jean; Compan, Vincent; Monet, Michael; Rassendren, François-A

2006-06-01

Cellular or chemical activators for most transient receptor potential channels of the vanilloid subfamily (TRPV) have been identified in recent years. A remarkable exception to this is TRPV2, for which cellular events leading to channel activation are still a matter of debate. Diverse stimuli such as extreme heat or phosphatidylinositol-3 kinase (PI3-kinase) regulated membrane insertion have been shown to promote TRPV2 channel activity. However, some of these results have proved difficult to reproduce and may underlie different gating mechanisms depending on the cell type in which TRPV2 channels are expressed. Here, we show that expression of recombinant TRPV2 can induce cytotoxicity that is directly related to channel activity since it can be prevented by introducing a charge substitution in the pore-forming domain of the channel, or by reducing extracellular calcium. In stably transfected cells, TRPV2 expression results in an outwardly rectifying current that can be recorded at all potentials, and in an increase of resting intracellular calcium concentration that can be partly prevented by serum starvation. Using cytotoxicity as a read-out of channel activity and direct measurements of cell surface expression of TRPV2, we show that inhibition of the PI3-kinase decreases TRPV2 channel activity but does not affect the trafficking of the channel to the plasma membrane. It is concluded that PI3-kinase induces or modulates the activity of recombinant TRPV2 channels; in contrast to the previously proposed mechanism, activation of TRPV2 channels by PI3-kinase is not due to channel translocation to the plasma membrane.

Protons stabilize the closed conformation of gain-of-function mutants of the TRPV1 channel.

PubMed

Boukalova, Stepana; Teisinger, Jan; Vlachova, Viktorie

2013-03-01

The vanilloid transient receptor potential channel TRPV1 is a molecular integrator of noxious stimuli, including capsaicin, heat and protons. Despite clear similarities between the overall architecture of TRPV1 and voltage-dependent potassium (Kv) channels, the extent of conservation in the molecular logic for gating is unknown. In Kv channels, a small contact surface between S1 and the pore-helix is required for channel functioning. To explore the function of S1 in TRPV1, we used tryptophan-scanning mutagenesis and characterized the responses to capsaicin and protons. Wild-type-like currents were generated in 9 out of 17 mutants; three mutants (M445W, A452W, R455W) were non-functional. The conservative mutation R455K in the extracellular extent of S1 slowed down capsaicin-induced activation and prevented normal channel closure. This mutant was neither activated nor potentiated by protons, on the contrary, protons promoted a rapid deactivation of its currents. Similar phenotypes were found in two other gain-of-function mutants and also in the pore-helix mutant T633A, known to uncouple proton activation. We propose that the S1 domain contains a functionally important region that may be specifically involved in TRPV1 channel gating, and thus be important for the energetic coupling between S1-S4 sensor activation and gate opening. Analogous to Kv channels, the S1-pore interface might serve to stabilize conformations associated with TRPV1 channel gating. Copyright © 2012 Elsevier B.V. All rights reserved.

XEN-D0501, a Novel Transient Receptor Potential Vanilloid 1 Antagonist, Does Not Reduce Cough in Patients with Refractory Cough.

PubMed

Belvisi, Maria G; Birrell, Mark A; Wortley, Michael A; Maher, Sarah A; Satia, Imran; Badri, Huda; Holt, Kimberley; Round, Patrick; McGarvey, Lorcan; Ford, John; Smith, Jaclyn A

2017-11-15

Heightened cough responses to inhaled capsaicin, a transient receptor potential vanilloid 1 (TRPV1) agonist, are characteristic of patients with chronic cough. However, previously, a TRPV1 antagonist (SB-705498) failed to improve spontaneous cough frequency in these patients, despite small reductions in capsaicin-evoked cough. XEN-D0501 (a potent TRPV1 antagonist) was compared with SB-705498 in preclinical studies to establish whether an improved efficacy profile would support a further clinical trial of XEN-D0501 in refractory chronic cough. XEN-D0501 and SB-705498 were profiled against capsaicin in a sensory nerve activation assay and in vivo potency established against capsaicin-induced cough in the guinea pig. Twenty patients with refractory chronic cough participated in a double-blind, randomized, placebo-controlled crossover study evaluating the effect of 14 days of XEN-D0501 (oral, 4 mg twice daily) versus placebo on awake cough frequency (primary outcome), capsaicin-evoked cough, and patient-reported outcomes. XEN-D0501 was more efficacious and 1,000-fold more potent than SB-705498 at inhibiting capsaicin-induced depolarization of guinea pig and human isolated vagus nerve. In vivo XEN-D0501 completely inhibited capsaicin-induced cough, whereas 100 times more SB-705498 was required to achieve the same effect. In patients, XEN-D0501 substantially reduced maximal cough responses to capsaicin (mean change from baseline, XEN-D0501, -19.3 ± 16.4) coughs; placebo, -1.8 ± 5.8 coughs; P < 0.0001), but not spontaneous awake cough frequency (mean change from baseline, XEN-D0501, 6.7  ± 16.9 coughs/h; placebo, 0.4 ± 13.7 coughs/h; P = 0.41). XEN-D0501 demonstrated superior efficacy and potency in preclinical and clinical capsaicin challenge studies; despite this improved pharmacodynamic profile, spontaneous cough frequency did not improve, ruling out TRPV1 as an effective therapeutic target for refractory cough. Clinical trial registered with www.clinicaltrialsregister.eu (2014-000306-36).

Genetic background can result in a marked or minimal effect of gene knockout (GPR55 and CB2 receptor) in experimental autoimmune encephalomyelitis models of multiple sclerosis.

PubMed

Sisay, Sofia; Pryce, Gareth; Jackson, Samuel J; Tanner, Carolyn; Ross, Ruth A; Michael, Gregory J; Selwood, David L; Giovannoni, Gavin; Baker, David

2013-01-01

Endocannabinoids and some phytocannabinoids bind to CB1 and CB2 cannabinoid receptors, transient receptor potential vanilloid one (TRPV1) receptor and the orphan G protein receptor fifty-five (GPR55). Studies using C57BL/10 and C57BL/6 (Cnr2 (tm1Zim)) CB2 cannabinoid receptor knockout mice have demonstrated an immune-augmenting effect in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis. However, other EAE studies in Biozzi ABH mice often failed to show any treatment effect of either CB2 receptor agonism or antagonism on inhibition of T cell autoimmunity. The influence of genetic background on the induction of EAE in endocannabinoid system-related gene knockout mice was examined. It was found that C57BL/6.GPR55 knockout mice developed less severe disease, notably in female mice, following active induction with myelin oligodendrocyte glycoprotein 35-55 peptide. In contrast C57BL/6.CB2 (Cnr2 (Dgen)) receptor knockout mice developed augmented severity of disease consistent with the genetically and pharmacologically-distinct, Cnr2 (tm1Zim) mice. However, when the knockout gene was bred into the ABH mouse background and EAE induced with spinal cord autoantigens the immune-enhancing effect of CB2 receptor deletion was lost. Likewise CB1 receptor and transient receptor potential vanilloid one knockout mice on the ABH background demonstrated no alteration in immune-susceptibility, in terms of disease incidence and severity of EAE, in contrast to that reported in some C57BL/6 mouse studies. Furthermore the immune-modulating influence of GPR55 was marginal on the ABH mouse background. Whilst sedative doses of tetrahydrocannabinol could induce immunosuppression, this was associated with a CB1 receptor rather than a CB2 receptor-mediated effect. These data support the fact that non-psychoactive doses of medicinal cannabis have a marginal influence on the immune response in MS. Importantly, it adds a note of caution for the translational value of some transgenic/gene knockout and other studies on low-EAE susceptibility backgrounds with inconsistent disease course and susceptibility.

Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis

PubMed Central

Jackson, Samuel J.; Tanner, Carolyn; Ross, Ruth A.; Michael, Gregory J.; Selwood, David L.; Giovannoni, Gavin; Baker, David

2013-01-01

Endocannabinoids and some phytocannabinoids bind to CB1 and CB2 cannabinoid receptors, transient receptor potential vanilloid one (TRPV1) receptor and the orphan G protein receptor fifty-five (GPR55). Studies using C57BL/10 and C57BL/6 (Cnr2 tm1Zim) CB2 cannabinoid receptor knockout mice have demonstrated an immune-augmenting effect in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis. However, other EAE studies in Biozzi ABH mice often failed to show any treatment effect of either CB2 receptor agonism or antagonism on inhibition of T cell autoimmunity. The influence of genetic background on the induction of EAE in endocannabinoid system-related gene knockout mice was examined. It was found that C57BL/6.GPR55 knockout mice developed less severe disease, notably in female mice, following active induction with myelin oligodendrocyte glycoprotein 35-55 peptide. In contrast C57BL/6.CB2 (Cnr2 Dgen) receptor knockout mice developed augmented severity of disease consistent with the genetically and pharmacologically-distinct, Cnr2 tm1Zim mice. However, when the knockout gene was bred into the ABH mouse background and EAE induced with spinal cord autoantigens the immune-enhancing effect of CB2 receptor deletion was lost. Likewise CB1 receptor and transient receptor potential vanilloid one knockout mice on the ABH background demonstrated no alteration in immune-susceptibility, in terms of disease incidence and severity of EAE, in contrast to that reported in some C57BL/6 mouse studies. Furthermore the immune-modulating influence of GPR55 was marginal on the ABH mouse background. Whilst sedative doses of tetrahydrocannabinol could induce immunosuppression, this was associated with a CB1 receptor rather than a CB2 receptor-mediated effect. These data support the fact that non-psychoactive doses of medicinal cannabis have a marginal influence on the immune response in MS. Importantly, it adds a note of caution for the translational value of some transgenic/gene knockout and other studies on low-EAE susceptibility backgrounds with inconsistent disease course and susceptibility. PMID:24130809

Preclinical characterization of three transient receptor potential vanilloid receptor 1 antagonists for early use in human intradermal microdose analgesic studies.

PubMed

Sjögren, E; Halldin, M M; Stålberg, O; Sundgren-Andersson, A K

2018-05-01

The transient receptor potential vanilloid receptor 1 (TRPV1) is a nonselective cation channel involved in the mediation of peripheral pain to the central nervous system. As such, the TRPV1 is an accessible molecular target that lends itself well to the understanding of nociceptive signalling. This study encompasses preclinical investigations of three molecules with the prospect to establish them as suitable analgesic model compounds in human intradermal pain relief studies. The inhibitory effectiveness was evaluated by means of in vitro assays, TRPV1 expressing Chinese hamster ovary cells (CHO-K1) and rat dorsal root ganglion cultures in fluorescent imaging plate reader and whole cell patch clamp systems, as well as in vivo by capsaicin-evoked pain-related behavioural response studies in rat. Secondary pharmacology, pharmacokinetics and preclinical safety were also assessed. In vitro, all three compounds were effective at inhibiting capsaicin-activated TRPV1. The concentration producing 50% inhibition (IC 50 ) determined was in the range of 3-32 nmol/L and 10-501 nmol/L using CHO-K1 and dorsal root ganglion cultures, respectively. In vivo, all compounds showed dose-dependent reduction in capsaicin-evoked pain-related behavioural responses in rat. None of the three compounds displayed any significant activity on any of the secondary targets tested. The compounds were also shown to be safe from a toxicological, drug metabolism and pharmacokinetic perspective, for usage in microgram doses in the human skin. The investigated model compounds displayed ideal compound characteristics as pharmacological and translational tools to address efficacy on the human native TRPV1 target in human skin in situ. This work details the pharmaceutical work-up of three TRPV1-active investigational compounds, to obtain regulatory approval, for subsequent use in humans. This fast and cost-effective preclinical development path may impact research beyond the pain management area, as it allows human target engagement information gathering early in drug development. © 2018 European Pain Federation - EFIC®.

TRPV1 recapitulates native capsaicin receptor in sensory neurons in association with Fas-associated factor 1.

PubMed

Kim, Sangsung; Kang, Changjoong; Shin, Chan Young; Hwang, Sun Wook; Yang, Young Duk; Shim, Won Sik; Park, Min-Young; Kim, Eunhee; Kim, Misook; Kim, Byung-Moon; Cho, Hawon; Shin, Youngki; Oh, Uhtaek

2006-03-01

TRPV1, a cloned capsaicin receptor, is a molecular sensor for detecting adverse stimuli and a key element for inflammatory nociception and represents biophysical properties of native channel. However, there seems to be a marked difference between TRPV1 and native capsaicin receptors in the pharmacological response profiles to vanilloids or acid. One plausible explanation for this overt discrepancy is the presence of regulatory proteins associated with TRPV1. Here, we identify Fas-associated factor 1 (FAF1) as a regulatory factor, which is coexpressed with and binds to TRPV1 in sensory neurons. When expressed heterologously, FAF1 reduces the responses of TRPV1 to capsaicin, acid, and heat, to the pharmacological level of native capsaicin receptor in sensory neurons. Furthermore, silencing FAF1 by RNA interference augments capsaicin-sensitive current in native sensory neurons. We therefore conclude that FAF1 forms an integral component of the vanilloid receptor complex and that it constitutively modulates the sensitivity of TRPV1 to various noxious stimuli in sensory neurons.

Long Non-coding RNA BC168687 is Involved in TRPV1-mediated Diabetic Neuropathic Pain in Rats.

PubMed

Liu, Chenglong; Li, Congcong; Deng, Zeyu; Du, Errong; Xu, Changshui

2018-03-15

Long noncoding RNAs (lncRNAs) participate in a diverse range of molecular and biological processes, and dysregulation of lncRNAs has been observed in the pathogenesis of various human diseases. We observed alterations in mechanical withdrawal thresholds (MWT) and thermal withdrawal latencies (TWL) in streptozotocin (STZ)-induced diabetic rats treated with small interfering RNA (siRNA) of lncRNA BC168687. We detected expression of transient receptor potential vanilloid type 1 (TRPV1) in rat dorsal root ganglia (DRG) by a series of molecular experiments. We determined relative levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in rat serum by enzyme-linked immunosorbent assay (ELISA). In addition, we examined extracellular regulated protein kinases (ERK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways by Western blot (WB). We showed that the MWT and TWL of diabetic rats increased significantly compared with control. Expression of TRPV1 receptors in DRG substantially decreased. Relative levels of TNF-α and IL-1β in the serum of lncRNA BC168687 siRNA-treated rats were reduced. Phosphorylation (p)-ERK and p-p38 signaling pathways in DRG were also decreased. Taken together, we concluded lncRNA BC168687 siRNA may alleviate TRPV1-mediated diabetic neuropathic pain. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Incensole acetate, an incense component, elicits psychoactivity by activating TRPV3 channels in the brain.

PubMed

Moussaieff, Arieh; Rimmerman, Neta; Bregman, Tatiana; Straiker, Alex; Felder, Christian C; Shoham, Shai; Kashman, Yoel; Huang, Susan M; Lee, Hyosang; Shohami, Esther; Mackie, Ken; Caterina, Michael J; Walker, J Michael; Fride, Ester; Mechoulam, Raphael

2008-08-01

Burning of Boswellia resin as incense has been part of religious and cultural ceremonies for millennia and is believed to contribute to the spiritual exaltation associated with such events. Transient receptor potential vanilloid (TRPV) 3 is an ion channel implicated in the perception of warmth in the skin. TRPV3 mRNA has also been found in neurons throughout the brain; however, the role of TRPV3 channels there remains unknown. Here we show that incensole acetate (IA), a Boswellia resin constituent, is a potent TRPV3 agonist that causes anxiolytic-like and antidepressive-like behavioral effects in wild-type (WT) mice with concomitant changes in c-Fos activation in the brain. These behavioral effects were not noted in TRPV3(-/-) mice, suggesting that they are mediated via TRPV3 channels. IA activated TRPV3 channels stably expressed in HEK293 cells and in keratinocytes from TRPV3(+/+) mice. It had no effect on keratinocytes from TRPV3(-/-) mice and showed modest or no effect on TRPV1, TRPV2, and TRPV4, as well as on 24 other receptors, ion channels, and transport proteins. Our results imply that TRPV3 channels in the brain may play a role in emotional regulation. Furthermore, the biochemical and pharmacological effects of IA may provide a biological basis for deeply rooted cultural and religious traditions.

Adaptive Plasticity of Vaginal Innervation in Term Pregnant Rats

PubMed Central

Liao, Zhaohui; Smith, Peter G.

2011-01-01

Changes in reproductive status place varied functional demands on the vagina. These include receptivity to male intromission and sperm transport in estrus, barrier functions during early pregnancy, and providing a conduit for fetal passage at parturition. Peripheral innervation regulates vaginal function, which in turn may be influenced by circulating reproductive hormones. We assessed vaginal innervation in diestrus and estrus (before and after the estrous cycle surge in estrogen), and in the early (low estrogen) and late (high estrogen) stages in pregnancy. In vaginal sections from cycling rats, axons immunoreactive for the pan-neuronal marker protein gene product 9.5 (PGP 9.5) showed a small reduction at estrus relative to diestrus, but this difference did not persist after correcting for changes in target size. No changes were detected in axons immunoreactive for tyrosine hydroxylase (sympathetic), vesicular acetylcholine transporter (parasympathetic), or calcitonin gene-related peptide and transient receptor potential vanilloid type 1 (TRPV-1; sensory nociceptors). In rats at 10 days of pregnancy, innervation was similar to that observed in cycling rats. However, at 21 days of pregnancy, axons immunoreactive for PGP 9.5 and each of the subpopulation-selective markers were significantly reduced both when expressed as percentage of sectional area or after correcting for changes in target size. Because peripheral nerves regulate vaginal smooth muscle tone, blood flow, and pain sensitivity, reductions in innervation may represent important adaptive mechanisms facilitating parturition. PMID:21666101

Discovery of (R)-1-(7-chloro-2,2-bis(fluoromethyl)chroman-4-yl)-3-(3-methylisoquinolin-5-yl)urea (A-1165442): a temperature-neutral transient receptor potential vanilloid-1 (TRPV1) antagonist with analgesic efficacy.

PubMed

Voight, Eric A; Gomtsyan, Arthur R; Daanen, Jerome F; Perner, Richard J; Schmidt, Robert G; Bayburt, Erol K; DiDomenico, Stanley; McDonald, Heath A; Puttfarcken, Pamela S; Chen, Jun; Neelands, Torben R; Bianchi, Bruce R; Han, Ping; Reilly, Regina M; Franklin, Pamela H; Segreti, Jason A; Nelson, Richard A; Su, Zhi; King, Andrew J; Polakowski, James S; Baker, Scott J; Gauvin, Donna M; Lewis, LaGeisha R; Mikusa, Joseph P; Joshi, Shailen K; Faltynek, Connie R; Kym, Philip R; Kort, Michael E

2014-09-11

The synthesis and characterization of a series of selective, orally bioavailable 1-(chroman-4-yl)urea TRPV1 antagonists is described. Whereas first-generation antagonists that inhibit all modes of TRPV1 activation can elicit hyperthermia, the compounds disclosed herein do not elevate core body temperature in preclinical models and only partially block acid activation of TRPV1. Advancing the SAR of this series led to the eventual identification of (R)-1-(7-chloro-2,2-bis(fluoromethyl)chroman-4-yl)-3-(3-methylisoquinolin-5-yl)urea (A-1165442, 52), an analogue that possesses excellent pharmacological selectivity, has a favorable pharmacokinetic profile, and demonstrates good efficacy against osteoarthritis pain in rodents.

Sensory fibers containing vanilloid receptor-1 (VR-1) mediate spinal cord stimulation-induced vasodilation.

PubMed

Wu, Mingyuan; Komori, Naoka; Qin, Chao; Farber, Jay P; Linderoth, Bengt; Foreman, Robert D

2006-08-30

Spinal cord stimulation (SCS) is used to improve peripheral blood flow in selected populations of patients with ischemia of the extremities. Previous studies show that antidromic activation of sensory fibers is an important mechanism that contributes to SCS-induced vasodilation. However, the characteristics of sensory fibers involved in vasodilation are not fully known. This study investigated the contribution of vanilloid receptor type 1 (VR-1) containing fibers to SCS-induced vasodilation. A unipolar ball electrode was placed on the left dorsal column at the lumbar 2-3 spinal cord segments (L2-L3) in sodium pentobarbital anesthetized, paralyzed and ventilated rats. Cutaneous blood flows from both ipsilateral (left) and contralateral (right) hind foot pads were recorded with laser Doppler flow perfusion monitors. SCS (50 Hz; 0.2 ms) was applied through the ball electrode at 30%, 60%, 90% and 300% of motor threshold (MT). Resiniferatoxin (RTX), an ultra potent analog of capsaicin and VR-1 receptor agonist, was used to suppress the activities of VR-1 containing sensory fibers. SCS at 30%, 60%, 90% and also at 300% of MT significantly increased cutaneous blood flow in the ipsilateral foot pad compared to that in the contralateral side. RTX (2 microg/kg, i.v.) significantly attenuated SCS-induced vasodilation of the ipsilateral side (P<0.05, n=7) compared with responses prior to RTX administration. A pledget of cotton soaked with RTX (2 microg/ml) placed on L2-L3 spinal cord significantly decreased SCS-induced vasodilation of the ipsilateral side at 30%, 60%, 90% and 300% of MT (P<0.05, n=7) compared with responses prior to RTX administration. Additionally, topical application of a pledget of cotton soaked with RTX (2 microg/ml) on the sciatic nerve at the middle level of the thigh or on the tibial nerve at the lower level of the lower hindlimb also decreased SCS-induced vasodilation (n=5). SCS-induced vasodilation is predominantly mediated via VR-1 containing sensory fibers.

Cannabinoids induce apathetic and impulsive patterns of choice through CB1 receptors and TRPV1 channels.

PubMed

Fatahi, Zahra; Reisi, Zahra; Rainer, Gregor; Haghparast, Abbas; Khani, Abbas

2018-05-01

Despite evidence from psychiatry and psychology clinics pointing to altered cognition and decision making following the consumption of cannabis, the effects of cannabis derivatives are still under dispute and the mechanisms of cannabinoid effects on cognition are not known. In this study, we used effort-based and delay-based decision tasks and showed that ACEA, a potent cannabinoid agonist induced apathetic and impulsive patterns of choice in rats in a dose-dependent manner when locally injected into the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC), respectively. Pre-treatment with AM251, a selective cannabinoid type 1 (CB1) receptor antagonist, reversed ACEA-induced impulsive and apathetic patterns of choice in doses higher than a minimally effective dose. Unlike CB1 receptor antagonist, pretreatment with capsazepine, a transient receptor potential vanilloid type 1 (TRPV1) channel antagonist, was effective only at an intermediary dose. Furthermore, capsazepine per se induced impulsivity and apathy at a high dose suggesting a basal tonic activation of TRPV1 channels that exist in the ACC and OFC to support cost-benefit decision making and to help avoid apathetic and impulsive patterns of decision making. Taken together, unlike previous reports supporting opposing roles for the CB1 receptors and TRPV1 channels in anxiety and panic behavior, our findings demonstrate a different sort of interaction between endocannabinoid and endovanilloid systems and suggest that both systems contribute to the cognitive disrupting effects of cannabinoids. Given prevalent occurrence of apathy and particularly impulsivity in psychiatric disorders, these results have significant implications for pharmacotherapy research targeting these receptors. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sex-dependent expression of TRPV1 in bladder arterioles

PubMed Central

Phan, Thieu X.; Ton, Hoai T.; Chen, Yue; Basha, Maureen E.

2016-01-01

Transient receptor potential vanilloid type 1 (TRPV1) is a major nociceptive ion channel implicated in bladder physiology and/or pathophysiology. However, the precise expression of TRPV1 in neuronal vs. nonneuronal bladder cells is uncertain. Here we used reporter mouse lines (TRPV1-Cre:tdTomato and TRPV1PLAP-nlacZ) to map expression of TRPV1 in postnatal bladder. TRPV1 was not detected in the urothelium, however, we found marked expression of TRPV1 lineage in sensory nerves, and surprisingly, in arterial/arteriolar smooth muscle (ASM) cells. Tomato fluorescence was prominent in the vesical arteries and in small-diameter (15–40 μm) arterioles located in the suburothelial layer with a near equal distribution in bladder dome and base. Notably, arteriolar TRPV1 expression was greater in females than in males and increased in both sexes after 90 days of age, suggesting sex hormone and age dependency. Analysis of whole bladder and vesical artery TRPV1 mRNA revealed a similar sex and developmental dependence. Pharmacological experiments confirmed functional TRPV1 protein expression; capsaicin increased intracellular Ca2+ in ∼15% of ASM cells from wild-type female bladders, but we observed no responses to capsaicin in bladder arterioles isolated from TRPV1-null mice. Furthermore, capsaicin triggered arteriole constriction that was rapidly reversed by the TRPV1 antagonist, BCTC. These data show that predominantly in postpubertal female mice, bladder ASM cells express functional TRPV1 channels that may act to constrict arterioles. TRPV1 may therefore play an important role in regulating the microcirculation of the female bladder, and this effect may be of significance during inflammatory conditions. PMID:27654891

Anti-inflammatory Properties of Cannabidiol, a Nonpsychotropic Cannabinoid, in Experimental Allergic Contact Dermatitis.

PubMed

Petrosino, Stefania; Verde, Roberta; Vaia, Massimo; Allarà, Marco; Iuvone, Teresa; Di Marzo, Vincenzo

2018-06-01

Phytocannabinoids modulate inflammatory responses by regulating the production of cytokines in several experimental models of inflammation. Cannabinoid type-2 (CB 2 ) receptor activation was shown to reduce the production of the monocyte chemotactic protein-2 (MCP-2) chemokine in polyinosinic-polycytidylic acid [poly-(I:C)]-stimulated human keratinocyte (HaCaT) cells, an in vitro model of allergic contact dermatitis (ACD). We investigated if nonpsychotropic cannabinoids, such as cannabidiol (CBD), produced similar effects in this experimental model of ACD. HaCaT cells were stimulated with poly-(I:C), and the release of chemokines and cytokines was measured in the presence of CBD or other phytocannabinoids (such as cannabidiol acid, cannabidivarin, cannabidivarinic acid, cannabichromene, cannabigerol, cannabigerolic acid, cannabigevarin, tetrahydrocannabivarin, and tetrahydrocannabivarinic acid) and antagonists of CB 1 , CB 2 , or transient receptor potential vanilloid type-1 (TRPV1) receptors. HaCaT cell viability following phytocannabinoid treatment was also measured. The cellular levels of endocannabinoids [anandamide (AEA), 2-arachidonoylglycerol] and related molecules (palmitoylethanolamide, oleoylethanolamide) were quantified in poly-(I:C)-stimulated HaCaT cells treated with CBD. We show that in poly-(I:C)-stimulated HaCaT cells, CBD elevates the levels of AEA and dose-dependently inhibits poly-(I:C)-induced release of MCP-2, interleukin-6 (IL-6), IL-8, and tumor necrosis factor- α in a manner reversed by CB 2 and TRPV1 antagonists 6-iodopravadoline (AM630) and 5'-iodio-resiniferatoxin (I-RTX), respectively, with no cytotoxic effect. This is the first demonstration of the anti-inflammatory properties of CBD in an experimental model of ACD. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

A novel inhibitor of active protein kinase G attenuates chronic inflammatory and osteoarthritic pain.

PubMed

Sung, Ying-Ju; Sofoluke, Nelson; Nkamany, Mary; Deng, Shixian; Xie, Yuli; Greenwood, Jeremy; Farid, Ramy; Landry, Donald W; Ambron, Richard T

2017-05-01

Activating PKG-1α induces a long-term hyperexcitability (LTH) in nociceptive neurons. Since the LTH correlates directly with chronic pain in many animal models, we tested the hypothesis that inhibiting PKG-1α would attenuate LTH-mediated pain. We first synthesized and characterized compound N46 (N-((3R,4R)-4-(4-(2-fluoro-3-methoxy-6-propoxybenzoyl)benzamido)pyrrolidin-3-yl)-1H-indazole-5-carboxamide). N46 inhibits PKG-1α with an IC50 of 7.5 nmol, was highly selective when tested against a panel of 274 kinases, and tissue distribution studies indicate that it does not enter the CNS. To evaluate its antinociceptive potential, we used 2 animal models in which the pain involves both activated PKG-1α and LTH. Injecting complete Freund's adjuvant (CFA) into the rat hind paw causes a thermal hyperalgesia that was significantly attenuated 24 hours after a single intravenous injection of N46. Next, we used a rat model of osteoarthritic knee joint pain and found that a single intra-articular injection of N46 alleviated the pain 14 days after the pain was established and the relief lasted for 7 days. Thermal hyperalgesia and osteoarthritic pain are also associated with the activation of the capsaicin-activated transient receptor protein vanilloid-1 (TRPV1) channel. We show that capsaicin activates PKG-1α in nerves and that a subcutaneous delivery of N46 attenuated the mechanical and thermal hypersensitivity elicited by exposure to capsaicin. Thus, PKG-1α appears to be downstream of the transient receptor protein vanilloid-1. Our studies provide proof of concept in animal models that a PKG-1α antagonist has a powerful antinociceptive effect on persistent, already existing inflammatory pain. They further suggest that N46 is a valid chemotype for the further development of such antagonists.

Recent advances in the study on capsaicinoids and capsinoids.

PubMed

Luo, Xiu-Ju; Peng, Jun; Li, Yuan-Jian

2011-01-10

Chili peppers are the major source of nature capsaicinoids, which consist of capsaicin, dihydrocapsaicin, nordihydrocapsaicin, homodihydrocapsaicin, and homocapsaicin, etc. Capsaicinoids are found to exert multiple pharmacological and physiological effects including the activities of analgesia, anticancer, anti-inflammation, antioxidant and anti-obesity. Therefore, capsaicinoids may have the potential value in clinic for pain relief, cancer prevention and weight loss. In addition, capsaicinoids also display the benefits on cardiovascular and gastrointestinal system. It has been shown that capsaicinoids are potential agonists of capsaicin receptor or transient receptor potential vanilloid subfamily member 1 (TRPV1). They could exert the effects not only through the receptor-dependent pathway but also through the receptor-independent one. CH-19 Sweet peppers are the source of nature capsinoids, which share similar structure with capsaicinoids and consist of capsiate, dihydrocapsiate, and nordihydrocapsiate, etc, Comparing with capsaicinoids, capsinoids are less pungent and easily broken down in the normal aqueous conditions. So far, it has been found that capsinoids possess the biological properties of antitumor, antioxidant and anti-obesity. Since capsinoids are less toxic than capsaicinoids, therefore, capsinoids may have the advantages over capsaicinoids in clinical applications such as cancer prevention and weight loss. Copyright © 2010 Elsevier B.V. All rights reserved.

Decreased sensory nerve excitation and bone pain associated with mouse Lewis lung cancer in TRPV1-deficient mice.

PubMed

Wakabayashi, Hiroki; Wakisaka, Satoshi; Hiraga, Toru; Hata, Kenji; Nishimura, Riko; Tominaga, Makoto; Yoneda, Toshiyuki

2018-05-01

Bone pain is one of the most common and life-limiting complications of cancer metastasis to bone. Although the mechanism of bone pain still remains poorly understood, bone pain is evoked as a consequence of sensitization and excitation of sensory nerves (SNs) innervating bone by noxious stimuli produced in the microenvironment of bone metastases. We showed that bone is innervated by calcitonin gene-related protein (CGRP) + SNs extending from dorsal root ganglia (DRG), the cell body of SNs, in mice. Mice intratibially injected with Lewis lung cancer (LLC) cells showed progressive bone pain evaluated by mechanical allodynia and flinching with increased CGRP + SNs in bone and augmented SN excitation in DRG as indicated by elevated numbers of pERK- and pCREB-immunoreactive neurons. Immunohistochemical examination of LLC-injected bone revealed that the tumor microenvironment is acidic. Bafilomycin A1, a selective inhibitor of H + secretion from vacuolar proton pump, significantly alleviated bone pain, indicating that the acidic microenvironment contributes to bone pain. We then determined whether the transient receptor potential vanilloid 1 (TRPV1), a major acid-sensing nociceptor predominantly expressed on SNs, plays a role in bone pain by intratibially injecting LLC cells in TRPV1-deficient mice. Bone pain and SN excitation in the DRG and spinal dorsal horn were significantly decreased in TRPV1 -/- mice compared with wild-type mice. Our results suggest that TRPV1 activation on SNs innervating bone by the acidic cancer microenvironment in bone contributes to SN activation and bone pain. Targeting acid-activated TRPV1 is a potential therapeutic approach to cancer-induced bone pain.

Effect of acetaminophen on osteoblastic differentiation and migration of MC3T3-E1 cells.

PubMed

Nakatsu, Yoshihiro; Nakagawa, Fumio; Higashi, Sen; Ohsumi, Tomoko; Shiiba, Shunji; Watanabe, Seiji; Takeuchi, Hiroshi

2018-02-01

N-acetyl-p-aminophenol (APAP, acetaminophen, paracetamol) is a widely used analgesic/antipyretic with weak inhibitory effects on cyclooxygenase (COX) compared to non-steroidal anti-inflammatory drugs (NSAIDs). The mechanism of action of APAP is mediated by its metabolite that activates transient receptor potential channels, including transient receptor potential vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) or the cannabinoid receptor type 1 (CB1). However, the exact molecular mechanism and target underlying the cellular actions of APAP remain unclear. Therefore, we investigated the effect of APAP on osteoblastic differentiation and cell migration, with a particular focus on TRP channels and CB1. Effects of APAP on osteoblastic differentiation and cell migration of MC3T3-E1, a mouse pre-osteoblast cell line, were assessed by the increase in alkaline phosphatase (ALP) activity, and both wound-healing and transwell-migration assays, respectively. APAP dose-dependently inhibited osteoblastic differentiation, which was well correlated with the effects on COX activity compared with other NSAIDs. In contrast, cell migration was promoted by APAP, and this effect was not correlated with COX inhibition. None of the agonists or antagonists of TRP channels and the CB receptor affected the APAP-induced cell migration, while the effect of APAP on cell migration was abolished by down-regulating TRPV4 gene expression. APAP inhibited osteoblastic differentiation via COX inactivation while it promoted cell migration independently of previously known targets such as COX, TRPV1, TRPA1 channels, and CB receptors, but through the mechanism involving TRPV4. APAP may have still unidentified molecular targets that modify cellular functions. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Contribution of sensory nerves to LPS-induced hyperresponsiveness of human isolated bronchi.

PubMed

Calzetta, Luigino; Luongo, Livio; Cazzola, Mario; Page, Clive; Rogliani, Paola; Facciolo, Francesco; Maione, Sabatino; Capuano, Annalisa; Rinaldi, Barbara; Matera, Maria Gabriella

2015-06-15

Bacterial lipopolysaccharide (LPS) can induce bronchial hyperresponsiveness (BHR), but the underlying mechanisms remain to be determined. Here, the possible contribution of sensory nerves to LPS-induced BHR was examined in human isolated bronchi to pharmacologically identify the mechanisms underlying this phenomenon. Human isolated bronchial tone was induced by electrical field stimulation (EFS). The responses of airways to LPS, with or without capsaicin desensitization or thiorphan treatment were studied and the transient receptor potential vanilloid type 1 (TRPV1) expression was assessed. We performed similar experiments in the presence of a TRPV1 or a neurokinin (NK) 2 receptor antagonist using SB366791 and GR159897, respectively. LPS increased (≃2.3-fold, P<0.001) the contraction induced by EFS, compared to control tissues. Acute administration of capsaicin enhanced (≃2.3-fold, P<0.001) the EFS-mediated contraction, but did not potentiate the effect of LPS. Thiorphan increased (≃1.3-fold, P<0.05) the contractile response of LPS treated tissues and, at lower frequencies, it enhanced (≃1.7-fold, P<0.001) the capsaicin-induced contraction. In capsaicin-desensitized bronchi, LPS did not modify (P>0.05) the EFS contractile response, nor after treatment with thiorphan. Capsaicin desensitization reduced (≃0.4-fold, P<0.001) the LPS-induced BHR. SB366791 and GR159897 prevented the LPS-induced BHR and the release of NKA. LPS increased (+85.3±9.5%, P<0.01) the surface membrane expression of TRPV1 in parasympathetic ganglia. Our results demonstrate the involvement of capsaicin-sensitive sensory nerves and neutral endopeptidases in LPS-induced BHR of the human bronchi, associated with an upregulation of TRPV1 and release of NKA. Copyright © 2015. Published by Elsevier Inc.

Temperature- and Touch-Sensitive Neurons Couple CNG and TRPV Channel Activities to Control Heat Avoidance in Caenorhabditis elegans

PubMed Central

Liu, Shu; Schulze, Ekkehard; Baumeister, Ralf

2012-01-01

Background Any organism depends on its ability to sense temperature and avoid noxious heat. The nematode Caenorhabditis elegans responds to noxious temperatures exceeding ∼35°C and also senses changes in its environmental temperature in the range between 15 and 25°C. The neural circuits and molecular mechanisms involved in thermotaxis have been successfully studied, whereas details of the thermal avoidance behavior remain elusive. In this work, we investigate neurological and molecular aspects of thermonociception using genetic, cell biological and physiological approaches. Methodology/Principal Findings We show here that the thermosensory neurons AFD, in addition to sensing temperature within the range within which the animals can thrive, also contribute to the sensation of noxious temperatures resulting in a reflex-like escape reaction. Distinct sets of interneurons are involved in transmitting thermonociception and thermotaxis, respectively. Loss of AFD is partially compensated by the activity of a pair of multidendritic, polymodal neurons, FLP, whereas laser ablation of both types of neurons abrogated the heat response in the head of the animals almost completely. A third pair of heat sensory neurons, PHC, is situated in the tail. We find that the thermal avoidance response requires the cell autonomous function of cGMP dependent Cyclic Nucleotide-Gated (CNG) channels in AFD, and the heat- and capsaicin-sensitive Transient Receptor Potential Vanilloid (TRPV) channels in the FLP and PHC sensory neurons. Conclusions/Significance Our results identify distinct thermal responses mediated by a single neuron, but also show that parallel nociceptor circuits and molecules may be used as back-up strategies to guarantee fast and efficient responses to potentially detrimental stimuli. PMID:22448218

Antinociceptive Effect of Ghrelin in a Rat Model of Irritable Bowel Syndrome Involves TRPV1/Opioid Systems.

PubMed

Mao, Yuqing; Li, Zhengyang; Chen, Kan; Yu, Huafang; Zhang, Shaoren; Jiang, Miao; Ma, Yuanhua; Liang, Chunli; Liu, Hongyan; Li, Huanqing; Hua, Qian; Zhou, Hao; Sun, Yonghong; Fan, Xiaoming

2017-01-01

Irritable bowel syndrome (IBS), defined as recurrent abdominal pain and changes in bowel habits, seriously affects quality of life and ability to work. Ghrelin is a brain-gut hormone, which has been reported to show antinociceptive effects in peripheral pain. We investigated the effect of ghrelin on visceral hypersensitivity and pain in a rat model of IBS. Maternal deprivation (MD) was used to provide a stress-induced model of IBS in Wistar rats. Colorectal distension (CRD) was used to detect visceral sensitivity, which was evaluated by abdominal withdrawal reflex (AWR) scores. Rats that were confirmed to have visceral hypersensitivity after MD were injected with ghrelin (10 µg/kg) subcutaneously twice a week from weeks 7 to 8. [D-Lys3]-GHRP-6 (100 nmol/L) and naloxone (100 nmol/L) were administered subcutaneously to block growth hormone secretagogue receptor 1α (GHS-R1α) and opioid receptors, respectively. Expression of transient receptor potential vanilloid type 1 (TRPV1) and µ and κ opioid receptors (MOR and KOR) in colon, dorsal root ganglion (DRG) and cerebral cortex tissues were detected by western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemical analyses and immunofluorescence. Ghrelin treatment increased expression of opioid receptors and inhibited expression of TRPV1 in colon, dorsal root ganglion (DRG) and cerebral cortex. The antinociceptive effect of ghrelin in the rat model of IBS was partly blocked by both the ghrelin antagonist [D-Lys3]-GHRP-6 and the opioid receptor antagonist naloxone. The results indicate that ghrelin exerted an antinociceptive effect, which was mediated via TRPV1/opioid systems, in IBS-induced visceral hypersensitivity. Ghrelin might potentially be used as a new treatment for IBS. © 2017 The Author(s). Published by S. Karger AG, Basel.

Downregulation of the cough reflex by aclidinium and tiotropium in awake and anesthetized rabbits.

PubMed

Mutolo, Donatella; Cinelli, Elenia; Iovino, Ludovica; Pantaleo, Tito; Bongianni, Fulvia

2016-06-01

Long-acting muscarinic receptor antagonists (LAMAs) have been reported to attenuate cough in preclinical and clinical studies. The present study was performed on rabbits to compare aclidinium and tiotropium efficacy in the downregulation of the cough reflex. This reflex was evoked by citric acid inhalation in unanesthetized animals and by both citric acid inhalation and mechanical stimulation of the tracheobronchial tree in anesthetized animals 90 min following the inhalation of each drug (nebulizer output always at 1 mL/min). Aclidinium 4 mg/mL and tiotropium 200 μg/mL inhaled in 1 min proved to have similar protective effect on methacholine-induced bronchoconstriction in anesthetized animals. The total dosage employed for aclidinium and tiotropium was 4 mg and 200 μg, respectively. In awake animals, similar reductions in the cough number were observed following 10-min inhalation of each drug with a slight, not significant tendency to higher antitussive effects for aclidinium. In anesthetized animals, 1-min inhalation of each drug caused similar depressant effects on cough responses induced by both mechanical and chemical stimulation. A complete suppression of cough responses to mechanical stimuli was seen in some preparations. The results strongly suggest that the LAMA-induced downregulation of cough may be mediated not only by transient receptor potential vanilloid type 1 channels, as already reported, but also by acid-sensing ion channels and mechanoreceptors. The route of administration along with the more rapid hydrolysis of aclidinium into inactive metabolites minimize potential systemic side effects and give to this drug a very favorable safety profile. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conservation of tubulin-binding sequences in TRPV1 throughout evolution.

PubMed

Sardar, Puspendu; Kumar, Abhishek; Bhandari, Anita; Goswami, Chandan

2012-01-01

Transient Receptor Potential Vanilloid sub type 1 (TRPV1), commonly known as capsaicin receptor can detect multiple stimuli ranging from noxious compounds, low pH, temperature as well as electromagnetic wave at different ranges. In addition, this receptor is involved in multiple physiological and sensory processes. Therefore, functions of TRPV1 have direct influences on adaptation and further evolution also. Availability of various eukaryotic genomic sequences in public domain facilitates us in studying the molecular evolution of TRPV1 protein and the respective conservation of certain domains, motifs and interacting regions that are functionally important. Using statistical and bioinformatics tools, our analysis reveals that TRPV1 has evolved about ∼420 million years ago (MYA). Our analysis reveals that specific regions, domains and motifs of TRPV1 has gone through different selection pressure and thus have different levels of conservation. We found that among all, TRP box is the most conserved and thus have functional significance. Our results also indicate that the tubulin binding sequences (TBS) have evolutionary significance as these stretch sequences are more conserved than many other essential regions of TRPV1. The overall distribution of positively charged residues within the TBS motifs is conserved throughout evolution. In silico analysis reveals that the TBS-1 and TBS-2 of TRPV1 can form helical structures and may play important role in TRPV1 function. Our analysis identifies the regions of TRPV1, which are important for structure-function relationship. This analysis indicates that tubulin binding sequence-1 (TBS-1) near the TRP-box forms a potential helix and the tubulin interactions with TRPV1 via TBS-1 have evolutionary significance. This interaction may be required for the proper channel function and regulation and may also have significance in the context of Taxol®-induced neuropathy.

Use Dependence of Heat Sensitivity of Vanilloid Receptor TRPV2

PubMed Central

Liu, Beiying; Qin, Feng

2016-01-01

Thermal TRP channels mediate temperature transduction and pain sensation. The vanilloid receptor TRPV2 is involved in detection of noxious heat in a subpopulation of high-threshold nociceptors. It also plays a critical role in development of thermal hyperalgesia, but the underlying mechanism remains uncertain. Here we analyze the heat sensitivity of the TRPV2 channel. Heat activation of the channel exhibits strong use dependence. Prior heat activation can profoundly alter its subsequent temperature responsiveness, causing decreases in both temperature activation threshold and slope sensitivity of temperature dependence while accelerating activation time courses. Notably, heat and agonist activations differ in cross use-dependence. Prior heat stimulation can dramatically sensitize agonist responses, but not conversely. Quantitative analyses indicate that the use dependence in heat sensitivity is pertinent to the process of temperature sensing by the channel. The use dependence of TRPV2 reveals that the channel can have a dynamic temperature sensitivity. The temperature sensing structures within the channel have multiple conformations and the temperature activation pathway is separate from the agonist activation pathway. Physiologically, the use dependence of TRPV2 confers nociceptors with a hypersensitivity to heat and thus provides a mechanism for peripheral thermal hyperalgesia. PMID:27074678

On the value of nuclear and mitochondrial gene sequences for reconstructing the phylogeny of vanilloid orchids (Vanilloideae, Orchidaceae)

PubMed Central

Cameron, Kenneth M.

2009-01-01

Background and Aims Most molecular phylogenetic studies of Orchidaceae have relied heavily on DNA sequences from the plastid genome. Nuclear and mitochondrial loci have only been superficially examined for their systematic value. Since 40% of the genera within Vanilloideae are achlorophyllous mycoheterotrophs, this is an ideal group of orchids in which to evaluate non-plastid gene sequences. Methods Phylogenetic reconstructions for Vanilloideae were produced using independent and combined data from the nuclear 18S, 5·8S and 26S rDNA genes and the mitochondrial atpA gene and nad1b-c intron. Key Results These new data indicate placements for genera such as Lecanorchis and Galeola, for which plastid gene sequences have been mostly unavailable. Nuclear and mitochondrial parsimony jackknife trees are congruent with each other and previously published trees based solely on plastid data. Because of high rates of sequence divergence among vanilloid orchids, even the short 5·8S rDNA gene provides impressive levels of resolution and support. Conclusions Orchid systematists are encouraged to sequence nuclear and mitochondrial gene regions along with the growing number of plastid loci available. PMID:19251715

Emerging targets and therapeutic approaches for the treatment of osteoarthritis pain.

PubMed

Rahman, Wahida; Dickenson, Anthony H

2015-06-01

Osteoarthritis is a complex and often painful disease that is inadequately controlled with current analgesics. This review discusses emerging targets and therapeutic approaches that may lead to the development of better analgesics. Aberrant excitability in peripheral and central pain pathways drives osteoarthritis pain, reversing this via modulation of nerve growth factor, voltage-gated sodium channel, voltage-gated calcium channel and transient receptor potential vanilloid one activity, and increasing inhibitory mechanisms through modulation of cannabinoid and descending modulatory systems hold promise for osteoarthritis pain therapy. Somatosensory phenotyping of chronic pain patients, as a surrogate of putative pain generating mechanisms, may predict patient response to treatment. Identification of new targets will inform and guide future research, aiding the development of more effective analgesics. Future clinical trial designs should implement sensory phenotyping of patients, as an inclusion or stratification criterion, in order to establish an individualized, mechanism-based treatment of osteoarthritis pain.

Neurogenic [corrected] and oropharyngeal dysphagia.

PubMed

Rofes, Laia; Clavé, Pere; Ouyang, Ann; Scharitzer, Martina; Pokieser, Peter; Vilardell, Natalia; Ortega, Omar

2013-10-01

Oropharyngeal dysphagia (OD) is a swallowing disorder caused by congenital abnormalities and structural damage and disease-associated damage of the oral cavity, pharynx, and upper esophageal sphincter. Patients with OD lack the protective mechanisms necessary for effective swallowing, exhibiting difficulty controlling food in the mouth and initiating a swallow, leading to choking, coughing, and nasal regurgitation. OD is a major risk factor for malnutrition, dehydration, and aspiration pneumonia. The following on OD includes commentaries on the application of simulation of oropharyngeal transient receptor potential vanilloid 1 (TRPV1) and maneuvers like the Shaker exercise to improve the safety and efficacy of swallow in OD patients; the prevalence of esophageal pathologies in OD patients and the need to evaluate the esophagus, esophagogastric junction, and stomach; and strategies for clinical screening to detect OD and aspiration among high-risk patients and to improve oral health care, maintain nutrition and hydration, and prevent aspiration pneumonia. © 2013 New York Academy of Sciences.

Cryo-electron microscopy structure of the TRPV2 ion channel.

PubMed

Zubcevic, Lejla; Herzik, Mark A; Chung, Ben C; Liu, Zhirui; Lander, Gabriel C; Lee, Seok-Yong

2016-02-01

Transient receptor potential vanilloid (TRPV) cation channels are polymodal sensors involved in a variety of physiological processes. TRPV2, a member of the TRPV family, is regulated by temperature, by ligands, such as probenecid and cannabinoids, and by lipids. TRPV2 has been implicated in many biological functions, including somatosensation, osmosensation and innate immunity. Here we present the atomic model of rabbit TRPV2 in its putative desensitized state, as determined by cryo-EM at a nominal resolution of ∼4 Å. In the TRPV2 structure, the transmembrane segment 6 (S6), which is involved in gate opening, adopts a conformation different from the one observed in TRPV1. Structural comparisons of TRPV1 and TRPV2 indicate that a rotation of the ankyrin-repeat domain is coupled to pore opening via the TRP domain, and this pore opening can be modulated by rearrangements in the secondary structure of S6.

Cryo-electron microscopy structure of the TRPV2 ion channel

PubMed Central

Chung, Ben C; Liu, Zhirui; Lander, Gabriel C; Lee, Seok-Yong

2016-01-01

Transient receptor potential vanilloid (TRPV) cation channels are polymodal sensors involved in a variety of physiological processes. TRPV2, a member of the TRPV family, is regulated by temperature, by ligands, such as probenecid and cannabinoids, and by lipids. TRPV2 has been implicated in many biological functions, including somatosensation, osmosensation and innate immunity. Here we present the atomic model of rabbit TRPV2 in its putative desensitized state, as determined by cryo-EM at a nominal resolution of ~4 Å. In the TRPV2 structure, the transmembrane segment 6 (S6), which is involved in gate opening, adopts a conformation different from the one observed in TRPV1. Structural comparisons of TRPV1 and TRPV2 indicate that a rotation of the ankyrin-repeat domain is coupled to pore opening via the TRP domain, and this pore opening can be modulated by rearrangements in the secondary structure of S6. PMID:26779611

Probenecid: novel use as a non-injurious positive inotrope acting via cardiac TRPV2 stimulation

PubMed Central

Koch, Sheryl E.; Gao, Xiaoqian; Haar, Lauren; Jiang, Min; Lasko, Valerie M.; Robbins, Nathan; Cai, Wenfeng; Brokamp, Cole; Varma, Priyanka; Tranter, Michael; Liu, Yong; Ren, Xiaoping; Lorenz, John N.; Wang, Hong-Sheng; Jones, W. Keith; Rubinstein, Jack

2012-01-01

Probenecid is a highly lipid soluble benzoic acid derivative originally used to increase serum antibiotic concentrations. It was later discovered to have uricosuric effects and was FDA approved for gout therapy. It has recently been found to be a potent agonist of Transient Receptor Potential Vanilloid 2 (TRPV2). We have shown that this receptor is in the cardiomyocyte and report a positive inotropic effect of the drug. Using echocardiography, Langendorff and isolated myocytes, we measured the change in contractility and, using TRPV2−/− mice, proved that the effect was mediated by TRPV2 channels in the cardiomyocytes. Analysis of the expression of Ca2+ handling and β-adrenergic signaling pathway proteins showed that the contractility was not increased through activation of the β-ADR. We propose that the response to probenecid is due to activation of TRPV2 channels secondary to SR release of Ca2+. PMID:22561103

[Advance in studies on TRPV1 and analgesic effect of traditional Chinese medicines].

PubMed

Liu, Xiao-Li; Lv, Cui; Zhang, Wen-Sheng

2014-05-01

Transient receptor potential vanilloid 1 (TRPV1) is a non-selective positive ion channel that is mainly expressed in sensory neurons and a member of transient receptor potential (TRP) family. The receptor could be activated by mechanical irritation, chemical irritation or endogenous ligand to mediate pains and cause injury to body functions. Traditional Chinese medicine believes that the mechanism of pain is that "stagnation leads to pain". Specifically, both of the contracture and tautness caused by cold and the blood stasis could result in blood impassability and pain. Most of traditional Chinese medicines for clearing heat and removing toxicity have the anti-inflammatory effect, while those for warming interior, and promoting blood circulation to remove blood stasis have the effect in smoothening blood vessels. Therefore, either with the anti-inflammatory effect or the effect in smoothening blood vessels, traditional Chinese medicines for clearing heat and removing toxicity, warming interior, and promoting blood circulation have the analgesic effect In this paper, the authors summarize the analgesic effect of the above three traditional Chinese medicines, with TRPV1 as the target.

Cannabidiol exerts sebostatic and antiinflammatory effects on human sebocytes

PubMed Central

Oláh, Attila; Tóth, Balázs I.; Borbíró, István; Sugawara, Koji; Szöllõsi, Attila G.; Czifra, Gabriella; Pál, Balázs; Ambrus, Lídia; Kloepper, Jennifer; Camera, Emanuela; Ludovici, Matteo; Picardo, Mauro; Voets, Thomas; Zouboulis, Christos C.; Paus, Ralf; Bíró, Tamás

2014-01-01

The endocannabinoid system (ECS) regulates multiple physiological processes, including cutaneous cell growth and differentiation. Here, we explored the effects of the major nonpsychotropic phytocannabinoid of Cannabis sativa, (-)-cannabidiol (CBD), on human sebaceous gland function and determined that CBD behaves as a highly effective sebostatic agent. Administration of CBD to cultured human sebocytes and human skin organ culture inhibited the lipogenic actions of various compounds, including arachidonic acid and a combination of linoleic acid and testosterone, and suppressed sebocyte proliferation via the activation of transient receptor potential vanilloid-4 (TRPV4) ion channels. Activation of TRPV4 interfered with the prolipogenic ERK1/2 MAPK pathway and resulted in the downregulation of nuclear receptor interacting protein-1 (NRIP1), which influences glucose and lipid metabolism, thereby inhibiting sebocyte lipogenesis. CBD also exerted complex antiinflammatory actions that were coupled to A2a adenosine receptor-dependent upregulation of tribbles homolog 3 (TRIB3) and inhibition of the NF-κB signaling. Collectively, our findings suggest that, due to the combined lipostatic, antiproliferative, and antiinflammatory effects, CBD has potential as a promising therapeutic agent for the treatment of acne vulgaris. PMID:25061872

TRPV1: A Potential Drug Target for Treating Various Diseases

PubMed Central

Brito, Rafael; Sheth, Sandeep; Mukherjea, Debashree; Rybak, Leonard P.; Ramkumar, Vickram

2014-01-01

Transient receptor potential vanilloid 1 (TRPV1) is an ion channel present on sensory neurons which is activated by heat, protons, capsaicin and a variety of endogenous lipids termed endovanilloids. As such, TRPV1 serves as a multimodal sensor of noxious stimuli which could trigger counteractive measures to avoid pain and injury. Activation of TRPV1 has been linked to chronic inflammatory pain conditions and peripheral neuropathy, as observed in diabetes. Expression of TRPV1 is also observed in non-neuronal sites such as the epithelium of bladder and lungs and in hair cells of the cochlea. At these sites, activation of TRPV1 has been implicated in the pathophysiology of diseases such as cystitis, asthma and hearing loss. Therefore, drugs which could modulate TRPV1 channel activity could be useful for the treatment of conditions ranging from chronic pain to hearing loss. This review describes the roles of TRPV1 in the normal physiology and pathophysiology of selected organs of the body and highlights how drugs targeting this channel could be important clinically. PMID:24861977

Gene polymorphisms associated with functional dyspepsia.

PubMed

Kourikou, Anastasia; Karamanolis, George P; Dimitriadis, George D; Triantafyllou, Konstantinos

2015-07-07

Functional dyspepsia (FD) is a constellation of functional upper abdominal complaints with poorly elucidated pathophysiology. However, there is increasing evidence that susceptibility to FD is influenced by hereditary factors. Genetic association studies in FD have examined genotypes related to gastrointestinal motility or sensation, as well as those related to inflammation or immune response. G-protein b3 subunit gene polymorphisms were first reported as being associated with FD. Thereafter, several gene polymorphisms including serotonin transporter promoter, interlukin-17F, migration inhibitory factor, cholecystocynine-1 intron 1, cyclooxygenase-1, catechol-o-methyltransferase, transient receptor potential vanilloid 1 receptor, regulated upon activation normal T cell expressed and secreted, p22PHOX, Toll like receptor 2, SCN10A, CD14 and adrenoreceptors have been investigated in relation to FD; however, the results are contradictory. Several limitations underscore the value of current studies. Among others, inconsistencies in the definitions of FD and controls, subject composition differences regarding FD subtypes, inadequate samples, geographical and ethnical differences, as well as unadjusted environmental factors. Further well-designed studies are necessary to determine how targeted genes polymorphisms, influence the clinical manifestations and potentially the therapeutic response in FD.

The role of TRPV1 in different subtypes of dorsal root ganglion neurons in rat chronic inflammatory nociception induced by complete Freund's adjuvant

PubMed Central

Yu, Lu; Yang, Fei; Luo, Hao; Liu, Feng-Yu; Han, Ji-Sheng; Xing, Guo-Gang; Wan, You

2008-01-01

Background The present study aims to investigate the role of transient receptor potential vanilloid 1 (TRPV1) in dorsal root ganglion (DRG) neurons in chronic pain including thermal hyperalgesia and mechanical allodynia. Chronic inflammatory nociception of rats was produced by intraplantar injection of complete Freund's adjuvant (CFA) and data was collected until day 28 following injection. Results Thermal hyperalgesia was evident from day 1 to day 28 with peak at day 7, while mechanical allodynia persisted from day 1 to day 14 and was greatest at day 7. Intrathecal administration of AMG 9810 at day 7, a selective TRPV1 antagonist, significantly reduced thermal hyperalgesia and mechanical allodynia. TRPV1 expression in DRG detected by Western blotting was increased relative to baseline throughout the observation period. Double labeling of TRPV1 with neuronal marker neurofilament 200 (NF200), calcitonin gene-related peptide (CGRP) or isolectin B4 (IB4) was used to distinguish different subtypes of DRG neurons. TRPV1 expression was increased in the medium-sized myelinated A fiber (NF200 positive) neurons and in small non-peptidergic (IB4 positive) neurons from day 1 to day 14 and was increased in small peptidergic (CGRP positive) neurons from day 1 to day 28. Conclusion TRPV1 expression increases in all three types of DRG neurons after CFA injection and plays a role in CFA-induced chronic inflammatory pain including thermal hyperalgesia and mechanical allodynia. PMID:19055783

Unravelling the Mystery of Capsaicin: A Tool to Understand and Treat Pain

PubMed Central

Brock, Christina; Olesen, Anne Estrup; Andresen, Trine; Nilsson, Matias; Dickenson, Anthony H.

2012-01-01

A large number of pharmacological studies have used capsaicin as a tool to activate many physiological systems, with an emphasis on pain research but also including functions such as the cardiovascular system, the respiratory system, and the urinary tract. Understanding the actions of capsaicin led to the discovery its receptor, transient receptor potential (TRP) vanilloid subfamily member 1 (TRPV1), part of the superfamily of TRP receptors, sensing external events. This receptor is found on key fine sensory afferents, and so the use of capsaicin to selectively activate pain afferents has been exploited in animal studies, human psychophysics, and imaging studies. Its effects depend on the dose and route of administration and may include sensitization, desensitization, withdrawal of afferent nerve terminals, or even overt death of afferent fibers. The ability of capsaicin to generate central hypersensitivity has been valuable in understanding the consequences and mechanisms behind enhanced central processing of pain. In addition, capsaicin has been used as a therapeutic agent when applied topically, and antagonists of the TRPV1 receptor have been developed. Overall, the numerous uses for capsaicin are clear; hence, the rationale of this review is to bring together and discuss the different types of studies that exploit these actions to shed light upon capsaicin working both as a tool to understand pain but also as a treatment for chronic pain. This review will discuss the various actions of capsaicin and how it lends itself to these different purposes. PMID:23023032

Piperine Promotes Glucose Uptake through ROS-Dependent Activation of the CAMKK/AMPK Signaling Pathway in Skeletal Muscle.

PubMed

Maeda, Ayumi; Shirao, Takeshi; Shirasaya, Daishi; Yoshioka, Yasukiyo; Yamashita, Yoko; Akagawa, Mitsugu; Ashida, Hitoshi

2018-06-01

The prevalence of type 2 diabetes mellitus (T2DM) is increasing yearly worldwide. Glycemic control is the basis for the treatment of T2DM, as it can prevent the progress of associated complications. Spices possess various health beneficial effects on humans. The aim of this study is to search for spices that can promote glucose uptake and to elucidate the underlying molecular mechanism(s). Among 24 spice extracts, the extracts from black pepper and white pepper significantly increase glucose uptake in L6 myotubes. Piperine is found to be the active compound in these extracts. Treatment of myotubes with piperine induces the translocation of glucose transporter 4 (GLUT4) to the plasma membrane by phosphorylation of AMP-activated protein kinase (AMPK). Piperine increases the intracellular Ca 2+ level and reactive oxygen species (ROS) generation through transient receptor potential vanilloid channel 1 (TRPV1), followed by activation of Ca 2+ /calmodulin-dependent protein kinase kinase-beta (CaMKKβ) as the upstream events for AMPK phosphorylation. Furthermore, oral administration of piperine to Wistar rats at 0.01 and 0.1 mg kg -1 body weight decreases postprandial hyperglycemia accompanied by GLUT4 translocation and AMPK phosphorylation. Piperine in pepper prevents hyperglycemia by GLUT4 translocation through CaMKKβ/AMPK signaling via TRPV1-dependent increase in the intracellular Ca 2+ level and ROS generation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Electroacupuncture on Rats with Chronic Constriction Injury-Induced Neuropathic Pain

PubMed Central

Tang, Nou-Ying; Lin, Yi-Wen; Li, Tsai-Chung; Liu, Hsu-Jan

2014-01-01

We adopt the chronic constriction injury (CCI) model to induce neuropathic pain to Spragrue-Dawley (SD) rats by ligating the right sciatic nerve of using four 4-0 chromic gut sutures and subsequently applying 2 and 15 Hz electroacupuncture (EA), respectively, to the right (ipsilateral) Zusanli (St-36) and Shangjuxu (St-37) acupoints. The results of this study are summarized as follows: (1) the differences in withdrawal latencies for the radiant heat test and total lift leg counts for the cold plate test (4°C) of the control (i.e., non-EA) and sham groups were greater than those of the 2 Hz EA (2EA) and 15 Hz EA (15EA) groups; (2) the von Frey test filament gram counts of the control and sham groups were less than those of the 2EA and 15EA groups on the 6th, 7th, 8th, 11th, 12th, and 13th day following ligation; and (3) the 2EA and 15EA groups exhibited reduced cerebral transient receptor potential vanilloid type 4 (TRPV4) expressions, although we did not observe a similar effect for cerebral TRPV1 or spinal TRPV4/TRPV1 expressions. These findings show that 2 and 15 Hz EA can reduce CCI-induced neuropathic pain, which indicates that various spinal segmental and gate effects have a crucial function in pain reduction. The relationship between EA and TRPV4/TRPV1 expression requires further study. PMID:24605047

Skeletal lipidomics: regulation of bone metabolism by fatty acid amide family.

PubMed

Bab, Itai; Smoum, Reem; Bradshaw, Heather; Mechoulam, Raphael

2011-08-01

There is increasing evidence demonstrating that fatty acid derivatives play a key regulatory role in a variety of tissues. However, the study of skeletal lipidomics is just emerging and global strategies, such as targeted lipidomics, have not been applied to bone tissue. Such strategies hold great promises as in the case of genomics and proteomics. A partial profile of endocannabinoids and endocannabinoid-like compounds has demonstrated the presence of several long-chain fatty acid amides (FAAs), some of which displaying potent effects on osteoblasts, the bone forming cells and osteoclasts, the bone resorbing cells. In the skeleton, the FAAs activate the CB(1) cannabinoid receptor present in sympathetic nerve terminals as well as CB(2) cannabinoid receptor, the Gi-protein coupled receptor GPR55, and the transient receptor potential vanilloid type ion channel expressed by osteoblasts and/or osteoclasts. This review on the skeletal FAA system focuses on the production of FAAs in the skeleton and their net bone anabolic and anti-catabolic activity resulting from the stimulation of bone formation and inhibition of bone resorption. As the FAA family holds great promise as a basis for the treatment of osteoporosis and other diseases involving bone, further studies should aim towards the complete profiling of these lipids and their receptors in bone tissue, followed by elucidation of their function and mechanism of action. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

[Effect of hydrostatic pressure on intracellular free calcium concentration and transient receptor potential vanilloid expression in human bladder smooth muscle cells].

PubMed

Han, Zhenwei; Wang, Kunjie; Chen, Lin; Wei, Tangqiang; Luo, Deyi; Li, Shengfu

2012-04-01

To explore the effect of hydrostatic pressure on intracellular free calcium concentration ([Ca2+]i) and the gene expression of transient receptor potential vanilloid (TRPV) in cultured human bladder smooth muscle cells (hb-SMCs), and to preliminarily probe into the possible molecular mechanism of hb-SMCs proliferation stimulated by hydrostatic pressure. The passage 6-7 hb-SMCs were loaded with Ca2+ indicator Fluo-3/AM. When the hb-SMCs were under 0 cm H2O (1cm H2O = 0.098 kPa) (group A) or 200 cm H2O hydrostatic pressure for 30 minutes (group B) and then removing the 200 cm H2O hydrostatic pressure (group C), the [Ca2+]i was measured respectively by inverted laser scanning confocal microscope. When the hb-SMCs were given the 200 cm H2O hydrostatic pressure for 0 hour, 2 hours, 6 hours, 12 hours, and 24 hours, the mRNA expressions of TRPV1, TRPV2, and TRPV4 were detected by RT-PCR technique. The [Ca2+]i of group A, group B, and group C were (100.808 +/- 1.724), (122.008 +/- 1.575), and (99.918 +/- 0.887) U, respectively; group B was significantly higher than groups A and C (P < 0.001). The [Ca2+]i of group C decreased to the base line level of group A after removing the pressure (t = 0.919, P = 0.394). The TRPV1, TRPV2, and TRPV4 genes expressed in hb-SMCs under 200 cm H2O hydrostatic pressure at 0 hour, 2 hours, 6 hours, 12 hours, and 24 hours, but the expressions had no obvious changes with time. There was no significant difference in the expressions of TRPV1, TRPV2, and TRPV4 among 3 groups (P > 0.05). The [Ca2+]i of hb-SMCs increases significantly under high hydrostatic pressure. As possible genes in stretch-activated cation channel, the TRPV1, TRPV2, and TRPV4 express in hb-SMCs under 200 cm H2O hydrostatic pressure. It is possible that the mechanical pressure regulates the [Ca2+]i of hb-SMCs by opening the stretch-activated cation channel rather than up-regulating its expression.

Ischemic Brain Injury Leads to Brain Edema via Hyperthermia-Induced TRPV4 Activation.

PubMed

Hoshi, Yutaka; Okabe, Kohki; Shibasaki, Koji; Funatsu, Takashi; Matsuki, Norio; Ikegaya, Yuji; Koyama, Ryuta

2018-06-20

Brain edema is characterized by an increase in net brain water content, which results in an increase in brain volume. Although brain edema is associated with a high fatality rate, the cellular and molecular processes of edema remain largely unclear. Here, we developed an in vitro model of ischemic stroke-induced edema in which male mouse brain slices were treated with oxygen-glucose deprivation (OGD) to mimic ischemia. We continuously measured the cross-sectional area of the brain slice for 150 min under macroscopic microscopy, finding that OGD induces swelling of brain slices. OGD-induced swelling was prevented by pharmacologically blocking or genetically knocking out the transient receptor potential vanilloid 4 (TRPV4), a member of the thermosensitive TRP channel family. Because TRPV4 is activated at around body temperature and its activation is enhanced by heating, we next elevated the temperature of the perfusate in the recording chamber, finding that hyperthermia induces swelling via TRPV4 activation. Furthermore, using the temperature-dependent fluorescence lifetime of a fluorescent-thermosensitive probe, we confirmed that OGD treatment increases the temperature of brain slices through the activation of glutamate receptors. Finally, we found that brain edema following traumatic brain injury was suppressed in TRPV4-deficient male mice in vivo Thus, our study proposes a novel mechanism: hyperthermia activates TRPV4 and induces brain edema after ischemia. SIGNIFICANCE STATEMENT Brain edema is characterized by an increase in net brain water content, which results in an increase in brain volume. Although brain edema is associated with a high fatality rate, the cellular and molecular processes of edema remain unclear. Here, we developed an in vitro model of ischemic stroke-induced edema in which mouse brain slices were treated with oxygen-glucose deprivation. Using this system, we showed that the increase in brain temperature and the following activation of the thermosensitive cation channel TRPV4 (transient receptor potential vanilloid 4) are involved in the pathology of edema. Finally, we confirmed that TRPV4 is involved in brain edema in vivo using TRPV4-deficient mice, concluding that hyperthermia activates TRPV4 and induces brain edema after ischemia. Copyright © 2018 the authors 0270-6474/18/385700-10$15.00/0.

Protein kinase C activation potentiates gating of the vanilloid receptor VR1 by capsaicin, protons, heat and anandamide

PubMed Central

Vellani, Vittorio; Mapplebeck, Sarah; Moriondo, Andrea; Davis, John B; McNaughton, Peter A

2001-01-01

The effects of activation of protein kinase C (PKC) on membrane currents gated by capsaicin, protons, heat and anandamide were investigated in primary sensory neurones from neonatal rat dorsal root ganglia (DRG) and in HEK293 cells (human embryonic kidney cell line) transiently or stably expressing the human vanilloid receptor hVR1. Maximal activation of PKC by a brief application of phorbol 12-myristate 13-acetate (PMA) increased the mean membrane current activated by a low concentration of capsaicin by 1.65-fold in DRG neurones and 2.18-fold in stably transfected HEK293 cells. Bradykinin, which activates PKC, also enhanced the response to capsaicin in DRG neurones. The specific PKC inhibitor RO31-8220 prevented the enhancement caused by PMA. Activation of PKC did not enhance the membrane current at high concentrations of capsaicin, showing that PKC activation increases the probability of channel opening rather than unmasking channels. Application of PMA alone activated an inward current in HEK293 cells transiently transfected with VR1. The current was suppressed by the VR1 antagonist capsazepine. PMA did not, however, activate a current in the large majority of DRG neurones nor in HEK293 cells stably transfected with VR1. Removing external Ca2+ enhanced the response to a low concentration of capsaicin 2.40-fold in DRG neurones and 3.42-fold in HEK293 cells. Activation of PKC in zero Ca2+ produced no further enhancement of the response to capsaicin in either DRG neurones or HEK293 cells stably transfected with VR1. The effects of PKC activation on the membrane current gated by heat, anandamide and low pH were qualitatively similar to those on the capsaicin-gated current. The absence of a current activated by PMA in most DRG neurones or in stably transfected HEK293 cells suggests that activation of PKC does not directly open VR1 channels, but instead increases the probability that they will be activated by capsaicin, heat, low pH or anandamide. Removal of calcium also potentiates activation, and PKC activation then has no further effect. The results are consistent with a model in which phosphorylation of VR1 by PKC increases the probability of channel gating by agonists, and in which dephosphorylation occurs by a calcium-dependent process. PMID:11483711

Low-level ultrahigh-frequency and ultrashort-pulse blue laser irradiation enhances osteoblast extracellular calcification by upregulating proliferation and differentiation via transient receptor potential vanilloid 1.

PubMed

Mikami, Risako; Mizutani, Koji; Aoki, Akira; Tamura, Yukihiko; Aoki, Kazuhiro; Izumi, Yuichi

2018-04-01

Low-level laser irradiation (LLLI) exerts various biostimulative effects, including promotion of wound healing and bone formation; however, few studies have examined biostimulation using blue lasers. The purpose of this study was to investigate the effects of low-level ultrahigh-frequency (UHF) and ultrashort-pulse (USP) blue laser irradiation on osteoblasts. The MC3T3-E1 osteoblast cell line was used in this study. Following LLLI with a 405 nm newly developed UHF-USP blue laser (80 MHz, 100 fs), osteoblast proliferation, and alkaline phosphatase (ALP) activity were assessed. In addition, mRNA levels of the osteoblast differentiation markers, runt-related transcription factor 2 (Runx2), osterix (Osx), alkaline phosphatase (Alp), and osteopontin (Opn) was evaluated, and extracellular calcification was quantified. To clarify the involvement of transient receptor potential (TRP) channels in LLLI-induced biostimulation, cells were treated prior to LLLI with capsazepine (CPZ), a selective inhibitor of TRP vanilloid 1 (TRPV1), and subsequent proliferation and ALP activity were measured. LLLI with the 405 nm UHF-USP blue laser significantly enhanced cell proliferation and ALP activity, compared with the non-irradiated control and LLLI using continuous-wave mode, without significant temperature elevation. LLLI promoted osteoblast proliferation in a dose-dependent manner up to 9.4 J/cm 2 and significantly accelerated cell proliferation in in vitro wound healing assay. ALP activity was significantly enhanced at doses up to 5.6 J/cm 2 , and expression of Osx and Alp mRNAs was significantly increased compared to that of the control on days 3 and 7 following LLLI at 5.6 J/cm 2 . The extent of extracellular calcification was also significantly higher as a result of LLLI 3 weeks after the treatment. Measurement of TRPV1 protein expression on 0, 3, and 7 days post-irradiation revealed no differences between the LLLI and control groups; however, promotion of cell proliferation and ALP activity by LLLI was significantly inhibited by CPZ. LLLI with a 405 nm UHF-USP blue laser enhances extracellular calcification of osteoblasts by upregulating proliferation and differentiation via TRPV1. Lasers Surg. Med. 50:340-352, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Chronic adriamycin treatment impairs CGRP-mediated functions of meningeal sensory nerves.

PubMed

Deák, Éva; Rosta, Judit; Boros, Krisztina; Kis, Gyöngyi; Sántha, Péter; Messlinger, Karl; Jancsó, Gábor; Dux, Mária

2018-06-01

Adriamycin is a potent anthracycline-type antitumor agent, but it also exerts potentially serious side effects due to its cardiotoxic and neurotoxic propensity. Multiple impairments in sensory nerve functions have been recently reported in various rat models. The present experiments were initiated in an attempt to reveal adriamycin-induced changes in sensory effector functions of chemosensitive meningeal afferents. Meningeal blood flow was measured with laser Doppler flowmetry in the parietal dura mater of adult male Wistar rats. The dura mater was repeatedly stimulated by topical applications of capsaicin, a transient receptor potential vanilloid 1 (TRPV1) receptor agonist, or acrolein, a transient receptor potential ankyrin 1 (TRPA1) receptor agonist, which induce the release of calcitonin gene-related peptide (CGRP) from meningeal afferents. The blood flow increasing effects of CGRP, histamine, acetylcholine and forskolin were also measured. Capsaicin- and acrolein-induced CGRP release was measured with enzyme-linked immunoassay in an ex vivo dura mater preparation. TRPV1 content of trigeminal ganglia and TRPV1-, CGRP- and CGRP receptor component-immunoreactive structures were examined in dura mater samples obtained from control and adriamycin-treated rats. The vasodilator effects of capsaicin, acrolein and CGRP were significantly reduced in adriamycin-treated animals while histamine-, acetylcholine- and forskolin-induced vasodilatation were unaffected. Measurements of CGRP release in an ex vivo dura mater preparation revealed an altered dynamic upon repeated stimulations of TRPV1 and TRPA1 receptors. In whole-mount dura mater preparations immunohistochemistry revealed altered CGRP receptor component protein (RCP)-immunoreactivity in adriamycin-treated animals, while CGRP receptor activity modifying protein (RAMP1)-, TRPV1- and CGRP-immunostaining were left apparently unaltered. Adriamycin-treatment slightly reduced TRPV1 protein content of trigeminal ganglia. The present findings demonstrate that adriamycin-treatment alters the function of the trigeminovascular system leading to reduced meningeal sensory neurogenic vasodilatation that may affect the local regulatory and protective mechanisms of chemosensitive afferents leading to alterations in tissue integrity. Copyright © 2018 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kikuno, Shota; Taguchi, Keiko; Iwamoto, Noriko

1,2-Naphthoquinone (1,2-NQ) has recently been identified as an environmental quinone in diesel exhaust particles (DEP) and atmospheric PM{sub 2.5}. We have found that this quinone is capable of causing a concentration-dependent contraction of tracheal smooth muscle in guinea pigs with EC{sub 5} value of 18.7 {mu}M. The contraction required extracellular calcium and was suppressed by L-type calcium channel blockers nifedipine and diltiazem. It was found that 1,2-NQ activated phospholipase A2 (PLA2)/lipoxygenase (LO)/vanilloid receptor (VR1) signaling. Additionally, 1,2-NQ was capable of transactivating protein tyrosine kinases (PTKs) such as epidermal growth factor receptor (EGFR) in guinea pig trachea, suggesting that phosphorylation ofmore » PTKs contributes to 1,2-NQ-induced tracheal contraction. Consistent with this notion, this action was blocked by the PTKs inhibitor genistein and the EGFR antagonist PD153035, indicating that contraction was, at least in part, attributable to PTKs phosphorylation that activates VR1, resulting in increased intracellular calcium content in the smooth muscle cells.« less

Use Dependence of Heat Sensitivity of Vanilloid Receptor TRPV2.

PubMed

Liu, Beiying; Qin, Feng

2016-04-12

Thermal TRP channels mediate temperature transduction and pain sensation. The vanilloid receptor TRPV2 is involved in detection of noxious heat in a subpopulation of high-threshold nociceptors. It also plays a critical role in development of thermal hyperalgesia, but the underlying mechanism remains uncertain. Here we analyze the heat sensitivity of the TRPV2 channel. Heat activation of the channel exhibits strong use dependence. Prior heat activation can profoundly alter its subsequent temperature responsiveness, causing decreases in both temperature activation threshold and slope sensitivity of temperature dependence while accelerating activation time courses. Notably, heat and agonist activations differ in cross use-dependence. Prior heat stimulation can dramatically sensitize agonist responses, but not conversely. Quantitative analyses indicate that the use dependence in heat sensitivity is pertinent to the process of temperature sensing by the channel. The use dependence of TRPV2 reveals that the channel can have a dynamic temperature sensitivity. The temperature sensing structures within the channel have multiple conformations and the temperature activation pathway is separate from the agonist activation pathway. Physiologically, the use dependence of TRPV2 confers nociceptors with a hypersensitivity to heat and thus provides a mechanism for peripheral thermal hyperalgesia. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Stress peptide PACAP engages multiple signaling pathways within the carotid body to initiate excitatory responses in respiratory and sympathetic chemosensory afferents.

PubMed

Roy, Arijit; Derakhshan, Fatemeh; Wilson, Richard J A

2013-06-15

Consistent with a critical role in respiratory and autonomic stress responses, the carotid bodies are strongly excited by pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide implicated in stress responses throughout the sympathetic nervous system. PACAP excites isolated carotid body glomus cells via activation of PAC1 receptors, with one study suggesting PAC1-induced excitation is due entirely to protein kinase A (PKA)-mediated inhibition of TASK channels. However, in other systems, PAC1 is known to be coupled to multiple intracellular signaling pathways, including PKA, phospholipase C (PLC), phospholipase D (PLD), and protein kinase C (PKC), that trigger multiple downstream effectors including increased Ca²⁺ mobilization, inhibition of various K⁺ channels, and activation of nonselective cation channels. This study tests if non-PKA/TASK channel signaling helps mediate the stimulatory effects of PACAP on the carotid body. Using an ex vivo arterially perfused rat carotid body preparation, we show that PACAP-38 stimulates carotid sinus nerve activity in a biphasic manner (peak response, falling to plateau). PKA blocker H-89 only reduced the plateau response (~41%), whereas the TASK-1-like K⁺ channel blocker/transient receptor potential vanilloid 1 channel agonist anandamide only inhibited the peak response (~48%), suggesting involvement of additional pathways. The PLD blocker CAY10594 significantly inhibited both peak and plateau responses. The PLC blocker U73122 decimated both peak and plateau responses. Brefeldin A, a blocker of Epac (cAMP-activated guanine exchange factor, reported to link Gs-coupled receptors with PLC/PLD), also reduced both phases of the response, as did blocking signaling downstream of PLC/PLD with the PKC inhibitors chelerythrine chloride and GF109203X. Suggesting the involvement of non-TASK ion channels in the effects of PACAP, the A-type K⁺ channel blocker 4-aminopyridine, and the putative transient receptor potential channel (TRPC)/T-type calcium channel blocker SKF96365 each significantly inhibited the peak and steady-state responses. These data suggest the stimulatory effect of PACAP-38 on carotid body sensory activity is mediated through multiple signaling pathways: the PLC-PKC pathways predominates, with TRPC and/or T-type channel activation and Kv channel inactivation; only partial involvement is attributable to PKA and PLD activation.

Local delivery of molecules from a nanopipette for quantitative receptor mapping on live cells.

PubMed

Babakinejad, Babak; Jönsson, Peter; López Córdoba, Ainara; Actis, Paolo; Novak, Pavel; Takahashi, Yasufumi; Shevchuk, Andrew; Anand, Uma; Anand, Praveen; Drews, Anna; Ferrer-Montiel, Antonio; Klenerman, David; Korchev, Yuri E

2013-10-01

Using nanopipettes to locally deliver molecules to the surface of living cells could potentially open up studies of biological processes down to the level of single molecules. However, in order to achieve precise and quantitative local delivery it is essential to be able to determine the amount and distribution of the molecules being delivered. In this work, we investigate how the size of the nanopipette, the magnitude of the applied pressure or voltage, which drives the delivery, and the distance to the underlying surface influences the number and spatial distribution of the delivered molecules. Analytical expressions describing the delivery are derived and compared with the results from finite element simulations and experiments on delivery from a 100 nm nanopipette in bulk solution and to the surface of sensory neurons. We then developed a setup for rapid and quantitative delivery to multiple subcellular areas, delivering the molecule capsaicin to stimulate opening of Transient Receptor Potential Vanilloid subfamily member 1 (TRPV1) channels, membrane receptors involved in pain sensation. Overall, precise and quantitative delivery of molecules from nanopipettes has been demonstrated, opening up many applications in biology such as locally stimulating and mapping receptors on the surface of live cells.

Exploration of the Esophageal Mucosal Barrier in Non-Erosive Reflux Disease

PubMed Central

Rinsma, Nicolaas F.; Farré, Ricard; Troost, Fred J.; Elizalde, Montserrat; Keszthelyi, Daniel; Helyes, Zsuzsanna; Masclee, Ad A.; Conchillo, José M.

2017-01-01

In the absence of visible mucosal damage, it is hypothesized that the esophageal mucosal barrier is functionally impaired in patients with non-erosive reflux disease (NERD). The aim of the present study was to perform an exploratory analysis of the mucosal barrier in NERD compared to erosive esophagitis (EE) and controls. A second aim was to explore TRPV1 gene transcription in relation to the mucosal barrier function and heartburn symptoms. In this prospective study, 10 NERD patients, 11 patients with active erosive esophagitis and 10 healthy volunteers were included. Biopsies from non-eroded mucosa were obtained for (1) ex vivo analyses (Ussing chamber) of transepithelial electrical resistance (TEER) and permeability (2) gene transcription of tight-junction proteins and transient receptor potential vanilloid subfamily member 1 (TRPV1). No differences in TEER or permeability were found between NERD and healthy volunteers, whereas TEER was lower in patients with erosive esophagitis. TRPV1 gene transcription was not significantly different between EE, NERD and controls. Conclusions: esophageal mucosal barrier function and TRPV1 transcription is not significantly altered in NERD patients. Future research is needed to explore other potential mechanisms that may account for the high symptom burden in these patients. PMID:28534850

The Effects of Capsaicin and Capsiate on Energy Balance: Critical Review and Meta-analyses of Studies in Humans

PubMed Central

Ludy, Mary-Jon; Moore, George E.

2012-01-01

Consumption of spicy foods containing capsaicin, the major pungent principle in hot peppers, reportedly promotes negative energy balance. However, many individuals abstain from spicy foods due to the sensory burn and pain elicited by the capsaicin molecule. A potential alternative for nonusers of spicy foods who wish to exploit this energy balance property is consumption of nonpungent peppers rich in capsiate, a recently identified nonpungent capsaicin analog contained in CH-19 Sweet peppers. Capsiate activates transient receptor potential vanilloid subtype 1 (TRPV1) receptors in the gut but not in the oral cavity. This paper critically evaluates current knowledge on the thermogenic and appetitive effects of capsaicin and capsiate from foods and in supplemental form. Meta-analyses were performed on thermogenic outcomes, with a systematic review conducted for both thermogenic and appetitive outcomes. Evidence indicates that capsaicin and capsiate both augment energy expenditure and enhance fat oxidation, especially at high doses. Furthermore, the balance of the literature suggests that capsaicin and capsiate suppress orexigenic sensations. The magnitude of these effects is small. Purposeful inclusion of these compounds in the diet may aid weight management, albeit modestly. PMID:22038945

Hyaluronan modulates TRPV1 channel opening, reducing peripheral nociceptor activity and pain

PubMed Central

Caires, Rebeca; Luis, Enoch; Taberner, Francisco J.; Fernandez-Ballester, Gregorio; Ferrer-Montiel, Antonio; Balazs, Endre A.; Gomis, Ana; Belmonte, Carlos; de la Peña, Elvira

2015-01-01

Hyaluronan (HA) is present in the extracellular matrix of all body tissues, including synovial fluid in joints, in which it behaves as a filter that buffers transmission of mechanical forces to nociceptor nerve endings thereby reducing pain. Using recombinant systems, mouse-cultured dorsal root ganglia (DRG) neurons and in vivo experiments, we found that HA also modulates polymodal transient receptor potential vanilloid subtype 1 (TRPV1) channels. HA diminishes heat, pH and capsaicin (CAP) responses, thus reducing the opening probability of the channel by stabilizing its closed state. Accordingly, in DRG neurons, HA decreases TRPV1-mediated impulse firing and channel sensitization by bradykinin. Moreover, subcutaneous HA injection in mice reduces heat and capsaicin nocifensive responses, whereas the intra-articular injection of HA in rats decreases capsaicin joint nociceptor fibres discharge. Collectively, these results indicate that extracellular HA reduces the excitability of the ubiquitous TRPV1 channel, thereby lowering impulse activity in the peripheral nociceptor endings underlying pain. PMID:26311398

Conformational plasticity in the selectivity filter of the TRPV2 ion channel.

PubMed

Zubcevic, Lejla; Le, Son; Yang, Huanghe; Lee, Seok-Yong

2018-05-01

Transient receptor potential vanilloid (TRPV) channels are activated by ligands and heat and are involved in various physiological processes. In contrast to the architecturally related voltage-gated cation channels, TRPV1 and TRPV2 subtypes possess another activation gate at the selectivity filter that can open widely enough to permeate large organic cations. Despite recent structural advances, the mechanism of selectivity filter gating and permeation for both metal ions and large molecules by TRPV1 or TRPV2 is not well known. Here, we determined two crystal structures of rabbit TRPV2 in its Ca 2+ -bound and resiniferatoxin (RTx)- and Ca 2+ -bound forms, to 3.9 Å and 3.1 Å, respectively. Notably, our structures show that RTx binding leads to two-fold symmetric opening of the selectivity filter of TRPV2 that is wide enough for large organic cation permeation. Combined with functional characterizations, our studies reveal a structural basis for permeation of Ca 2+ and large organic cations in TRPV2.

Unveiling TRPV1 Spatio-Temporal Organization in Live Cell Membranes

PubMed Central

Storti, Barbara; Di Rienzo, Carmine; Cardarelli, Francesco; Bizzarri, Ranieri; Beltram, Fabio

2015-01-01

Transient Receptor Potential Vanilloid 1 (TRPV1) is a non-selective cation channel that integrates several stimuli into nociception and neurogenic inflammation. Here we investigated the subtle TRPV1 interplay with candidate membrane partners in live cells by a combination of spatio-temporal fluctuation techniques and fluorescence resonance energy transfer (FRET) imaging. We show that TRPV1 is split into three populations with fairly different molecular properties: one binding to caveolin-1 and confined into caveolar structures, one actively guided by microtubules through selective binding, and one which diffuses freely and is not directly implicated in regulating receptor functionality. The emergence of caveolin-1 as a new interactor of TRPV1 evokes caveolar endocytosis as the main desensitization pathway of TRPV1 receptor, while microtubule binding agrees with previous data suggesting the receptor stabilization in functional form by these cytoskeletal components. Our results shed light on the hitherto unknown relationships between spatial organization and TRPV1 function in live-cell membranes. PMID:25764349

Resolution of cannabis hyperemesis syndrome with topical capsaicin in the emergency department: a case series.

PubMed

Dezieck, Laurel; Hafez, Zachary; Conicella, Albert; Blohm, Eike; O'Connor, Mark J; Schwarz, Evan S; Mullins, Michael E

2017-09-01

Cannabinoid hyperemesis syndrome (CHS) is characterized by symptoms of cyclic abdominal pain, nausea, and vomiting in the setting of prolonged cannabis use. The transient receptor potential vanilloid 1 (TRPV1) receptor may be involved in this syndrome. Topical capsaicin is a proposed treatment for CHS; it binds TRPV1 with high specificity, impairing substance P signaling in the area postrema and nucleus tractus solitarius via overstimulation of TRPV1. This may explain its apparent antiemetic effect in this syndrome. We describe a series of thirteen cases of suspected cannabis hyperemesis syndrome treated with capsaicin in the emergency departments of two academic medical centers. A query of the electronic health record at both centers identified thirteen patients with documented daily cannabis use and symptoms consistent with CHS who were administered topical capsaicin cream for symptom management. All 13 patients experienced symptom relief after administration of capsaicin cream. Topical capsaicin was associated with improvement in symptoms of CHS after other treatments failed.

Heteromerization and colocalization of TrpV1 and TrpV2 in mammalian cell lines and rat dorsal root ganglia.

PubMed

Rutter, A Richard; Ma, Qing-Ping; Leveridge, Mathew; Bonnert, Timothy P

2005-11-07

Coassociation of the vanilloid transient receptor potential (Trp) ion channels, TrpV1 and TrpV2, was investigated by immunoprecipitation and immunofluorescence in transfected mammalian cell lines, rat dorsal root ganglia and spinal cord. TrpV1/TrpV2 heteromeric complexes were coimmunoprecipitated from human embryonic kidney cells and F-11 dorsal root ganglion hybridoma cells following their transient coexpression. Immunofluorescent labelling of transfected F-11 cells revealed colocalization of TrpV1 and TrpV2 at the cell surface. Immunoprecipitation from rat dorsal root ganglion lysates identified a minor population of receptor complexes composed of TrpV1/TrpV2 heteromers, consistent with a small proportion of cells double-labelled with TrpV1 and TrpV2 antibodies in rat dorsal root ganglion sections. TrpV1/TrpV2 receptor complexes may represent a functionally distinct ion channel complex that may increase the diversity observed within the Trp ion channel family.

Structural Insight into the Assembly of TRPV Channels

PubMed Central

Huynh, Kevin W.; Cohen, Matthew R.; Chakrapani, Sudha; Holdaway, Heather A.; Stewart, Phoebe L.; Moiseenkova-Bell, Vera Y.

2017-01-01

SUMMARY Transient receptor potential (TRP) proteins are a large family of polymodal nonselective cation channels. The TRP vanilloid (TRPV) subfamily consists of six homologous members with diverse functions. TRPV1–TRPV4 are nonselective cation channels proposed to play a role in nociception, while TRPV5 and TRPV6 are involved in epithelial Ca2+ homeostasis. Here we present the cryo-electron microscopy (cryo-EM) structure of functional, full-length TRPV2 at 13.6 Å resolution. The map reveals that the TRPV2 cytoplasmic domain displays a 4-fold petal-like shape in which high-resolution N-terminal ankyrin repeat domain (ARD) structures can be unambiguously fitted. Fitting of the available ARD structures for other TRPV subfamily members into the TRPV2 EM map suggests that TRPV subfamily members have highly homologous structural topologies. These results allowed us to postulate a structural explanation for the functional diversity among TRPV channels and their differential regulation by proteins and ligands. PMID:24373766

Probenecid: novel use as a non-injurious positive inotrope acting via cardiac TRPV2 stimulation.

PubMed

Koch, Sheryl E; Gao, Xiaoqian; Haar, Lauren; Jiang, Min; Lasko, Valerie M; Robbins, Nathan; Cai, Wenfeng; Brokamp, Cole; Varma, Priyanka; Tranter, Michael; Liu, Yong; Ren, Xiaoping; Lorenz, John N; Wang, Hong-Sheng; Jones, W Keith; Rubinstein, Jack

2012-07-01

Probenecid is a highly lipid soluble benzoic acid derivative originally used to increase serum antibiotic concentrations. It was later discovered to have uricosuric effects and was FDA approved for gout therapy. It has recently been found to be a potent agonist of transient receptor potential vanilloid 2 (TRPV2). We have shown that this receptor is in the cardiomyocyte and report a positive inotropic effect of the drug. Using echocardiography, Langendorff and isolated myocytes, we measured the change in contractility and, using TRPV2(-/-) mice, proved that the effect was mediated by TRPV2 channels in the cardiomyocytes. Analysis of the expression of Ca(2+) handling and β-adrenergic signaling pathway proteins showed that the contractility was not increased through activation of the β-ADR. We propose that the response to probenecid is due to activation of TRPV2 channels secondary to SR release of Ca(2+). Copyright © 2012 Elsevier Ltd. All rights reserved.

A novel shogaol analog suppresses cancer cell invasion and inflammation, and displays cytoprotective effects through modulation of NF-κB and Nrf2-Keap1 signaling pathways.

PubMed

Gan, Fei-Fei; Ling, Hui; Ang, Xiaohui; Reddy, Shridhivya A; Lee, Stephanie S-H; Yang, Hong; Tan, Sock-Hoon; Hayes, John D; Chui, Wai-Keung; Chew, Eng-Hui

2013-11-01

Natural compounds containing vanilloid and Michael acceptor moieties appear to possess anti-cancer and chemopreventive properties. The ginger constituent shogaol represents one such compound. In this study, the anti-cancer potential of a synthetic novel shogaol analog 3-phenyl-3-shogaol (3-Ph-3-SG) was assessed by evaluating its effects on signaling pathways. At non-toxic concentrations, 3-Ph-3-SG suppressed cancer cell invasion in MDA-MB-231 and MCF-7 breast carcinoma cells through inhibition of PMA-activated MMP-9 expression. At similar concentrations, 3-Ph-3-SG reduced expression of the inflammatory mediators nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and prostanglandin-E2 (PGE2) in RAW 264.7 macrophage-like cells. Inhibition of cancer cell invasion and inflammation by 3-Ph-3-SG were mediated through suppression of the nuclear factor-kappaB (NF-κB) signaling pathway. The 3-Ph-3-SG also demonstrated cytoprotective effects by inducing the antioxidant response element (ARE)-driven genes NAD(P)H quinone oxidoreductase-1 (NQO1) and heme oxygenase-1 (HO-1). Cytoprotection by 3-Ph-3-SG was achieved at least partly through modification of cysteine residues in the E3 ubiquitin ligase substrate adaptor Kelch-like ECH-associated protein 1 (Keap1), which resulted in accumulation of transcription factor NF-E2 p45-related factor 2 (Nrf2). The activities of 3-Ph-3-SG were comparable to those of 6-shogaol, the most abundant naturally-occurring shogaol, and stronger than those of 4-hydroxyl-null deshydroxy-3-phenyl-3-shogaol, which attested the importance of the 4-hydroxy substituent in the vanilloid moiety for bioactivity. In summary, 3-Ph-3-SG is shown to possess activities that modulate stress-associated pathways relevant to multiple steps in carcinogenesis. Therefore, it warrants further investigation of this compound as a promising candidate for use in chemotherapeutic and chemopreventive strategies. © 2013.

Ethanol potentiates heat response in the carotid artery via TRPV1.

PubMed

Mustafa, Seham; Ismael, Hishaam N

2017-11-01

Ethanol is one of the most widely used recreational drugs in the world. At high concentrations, it can induce carotid artery vasoconstriction. Hyperthermia potentiates its effects resulting in carotid artery vasoconstriction at any concentration. The aim of this study is to investigate the interaction between ethanol and heating and to understand the underlying mechanisms leading to their synergistic effect. Isometric tension of rabbit carotid artery ring segments suspended in organ baths filled with Krebs solution was recorded. Different concentrations of ethanol were examined at 37°C and during temperature elevation to39-43°C. Capsaicin and capsazepine were used to examine the mechanism of action of ethanol. Ethanol induced contraction at 37°C when the concentration reached 100mM. Contraction was observed at any concentration at higher temperatures. Ethanol potentiated heat-induced contraction. Capsaicin, the vanilloid receptor subtype1 (TRPV1) agonist, potentiated the vasoconstriction due to heating. While capsazepine, TRPV1 antagonist, abolished the effect of ethanol and its potentiation of heating-induced contraction, but it did not abolish the heating effect. Ethanol's mechanism of action and its effect on heating induced-vasoconstriction of the carotid artery is being mediated by TRPV1. The combination of ethanol and hyperthermia can lead to a synergistic effect on carotid vasoconstriction. This effect may induce brain damage and heat stroke. Development of new drugs act as TRPV1 antagonist can be used to prevent these fatal effects. Copyright © 2017 Elsevier Inc. All rights reserved.

HIV-1-Tat excites cardiac parasympathetic neurons of nucleus ambiguus and triggers prolonged bradycardia in conscious rats

PubMed Central

Brailoiu, Eugen; Deliu, Elena; Sporici, Romeo A.; Benamar, Khalid

2014-01-01

The mechanisms of autonomic imbalance and subsequent cardiovascular manifestations in HIV-1-infected patients are poorly understood. We report here that HIV-1 transactivator of transcription (Tat, fragment 1–86) produced a concentration-dependent increase in cytosolic Ca2+ in cardiac-projecting parasympathetic neurons of nucleus ambiguus retrogradely labeled with rhodamine. Using store-specific pharmacological agents, we identified several mechanisms of the Tat-induced Ca2+ elevation: 1) lysosomal Ca2+ mobilization, 2) Ca2+ release via inositol 1,4,5-trisphosphate-sensitive endoplasmic reticulum pools, and 3) Ca2+ influx via transient receptor potential vanilloid type 2 (TRPV2) channels. Activation of TRPV2, nonselective cation channels, induced a robust and prolonged neuronal membrane depolarization, thus triggering an additional P/Q-mediated Ca2+ entry. In vivo microinjection studies indicate a dose-dependent, prolonged bradycardic effect of Tat administration into the nucleus ambiguus of conscious rats, in which neuronal TRPV2 played a major role. Our results support previous studies, indicating that Tat promotes bradycardia and, consequently, may be involved in the QT interval prolongation reported in HIV-infected patients. In the context of an overall HIV-dependent autonomic dysfunction, these Tat-mediated mechanisms may account for the higher prevalence of sudden cardiac death in HIV-1-infected patients compared with general population with similar risk factors. Our results may be particularly relevant in view of the recent findings that significant Tat levels can still be identified in the cerebrospinal fluid of HIV-infected patients with viral load suppression due to efficient antiretroviral therapy. PMID:24694382

Loss of TRPV4 Function Suppresses Inflammatory Fibrosis Induced by Alkali-Burning Mouse Corneas

PubMed Central

Okada, Yuka; Shirai, Kumi; Miyajima, Masayasu; Reinach, Peter S.; Yamanaka, Osamu; Sumioka, Takayoshi; Kokado, Masahide; Tomoyose, Katsuo; Saika, Shizuya

2016-01-01

In humans suffering from pulmonary disease and a mouse model, transient receptor potential vanilloid 4 (TRPV4) channel activation contributes to fibrosis. As a corneal alkali burn induces the same response, we determined if such an effect is also attributable to TRPV4 activation in mice. Accordingly, we determined if the alkali burn wound healing responses in wild-type (WT) mice are different than those in their TRPV4-null (KO) counterpart. Stromal opacification due to fibrosis in KO (n = 128) mice was markedly reduced after 20 days relative to that in WT (n = 157) mice. Immunohistochemistry revealed that increases in polymorphonuclear leukocytes and macrophage infiltration declined in KO mice. Semi-quantitative real time RT-PCR of ocular KO fibroblast cultures identified increases in proinflammatory and monocyte chemoattractant protein-1 chemoattractant gene expression after injury. Biomarker gene expression of fibrosis, collagen1a1 and α-smooth muscle actin were attenuated along with macrophage release of interleukin-6 whereas transforming growth factor β, release was unchanged. Tail vein reciprocal bone marrow transplantation between WT and KO chimera mouse models mice showed that reduced scarring and inflammation in KO mice are due to loss of TRPV4 expression on both corneal resident immune cells, fibroblasts and infiltrating polymorphonuclear leukocytes and macrophages. Intraperitoneal TRPV4 receptor antagonist injection of HC-067047 (10 mg/kg, daily) into WT mice reproduced the KO-phenotype. Taken together, alkali-induced TRPV4 activation contributes to inducing fibrosis and inflammation since corneal transparency recovery was markedly improved in KO mice. PMID:28030558

Evidence for CGRP re-uptake in rat dura mater encephali

PubMed Central

Gupta, Saurabh; Amrutkar, Dipak Vasantrao; Mataji, Aydin; Salmasi, Hassan; Hay-Schmidt, Anders; Sheykhzade, Majid; Messlinger, Karl; Olesen, Jes; Jansen-Olesen, Inger

2010-01-01

BACKGROUND AND PURPOSE Calcitonin gene-related peptide (CGRP) is widely distributed in the trigeminovascular system and released from sensory fibres of the cranial dura mater upon noxious stimulation. Such release may be a mechanism underlying migraine headache. Based on data from guinea pig basilar artery preparations, we have here studied CGRP release and uptake in an organ preparation of the hemisected rat skull. EXPERIMENTAL APPROACH CGRP release from the cranial dura was quantified by a commercial enzyme-linked immunoassay. CGRP was depleted using repetitive challenges of capsaicin. After incubating the tissue with CGRP for 20 min and extensive washing, another capsaicin challenge was performed. Immunohistochemistry was used to visualize CGRP immunofluorescence in dural nerve fibres. KEY RESULTS Capsaicin-induced CGRP release was attenuated by the transient receptor potential vanilloid receptor type I antagonist capsazepine or by Ca2+-free solutions. After the CGRP-depleted preparation had been exposed to exogenous CGRP, capsaicin-induced CGRP release was increased compared to the challenge just prior to incubation. CGRP uptake was not influenced by Ca2+-free solutions. Olcegepant and CGRP8–37 (CGRP receptor antagonists) did not affect uptake of CGRP. However, a monoclonal CGRP-binding antibody decreased CGRP uptake significantly. Release of CGRP after incubation was attenuated by Ca2+-free solutions and by capsazepine. Immunohistochemical assays indicated a weak trend towards CGRP uptake in rat dura mater. CONCLUSION AND IMPLICATIONS We have presented evidence for CGRP uptake in nerves and its re-release in rat dura mater. This may have implications for the pathophysiology and treatment of migraine. PMID:20804493

Increased TRPV4 expression in urinary bladder and lumbosacral dorsal root ganglia in mice with chronic overexpression of NGF in urothelium.

PubMed

Girard, Beatrice M; Merrill, Liana; Malley, Susan; Vizzard, Margaret A

2013-10-01

Transient receptor potential vanilloid (TRPV) family member 4 (TRPV4) expression has been demonstrated in urothelial cells and dorsal root ganglion (DRG) neurons, and roles in normal micturition reflexes as well as micturition dysfunction have been suggested. TRP channel expression and function is dependent upon target tissue expression of growth factors. These studies expand upon the target tissue dependence of TRPV4 expression in the urinary bladder and lumbosacral DRG using a recently characterized transgenic mouse model with chronic overexpression of nerve growth factor (NGF-OE) in the urothelium. Immunohistochemistry with image analyses, real-time quantitative polymerase chain reaction, and Western blotting were used to determine TRPV4 protein and transcript expression in the urinary bladder (urothelium + suburothelium, detrusor) and lumbosacral DRG from littermate wild-type (WT) and NGF-OE mice. Antibody specificity controls were performed in TRPV4(-/-) mice. TRPV4 transcript and protein expression was significantly (p ≤ 0.001) increased in the urothelium + suburothelium and suburothelial nerve plexus of the urinary bladder and in small- and medium-sized lumbosacral (L1, L2, L6-S1) DRG cells from NGF-OE mice compared to littermate WT mice. NGF-OE mice exhibit significant (p ≤ 0.001) increases in NGF transcript and protein in the urothelium + suburothelium and lumbosacral DRG. These studies demonstrate regulation of TRPV4 expression by NGF in lower urinary tract tissues. Ongoing studies are characterizing the functional roles of TRPV4 expression in the sensory limb (DRG, urothelium) of the micturition reflex.

Downregulation of adenosine and adenosine 1 receptor contributes to neuropathic pain in resiniferatoxin neuropathy.

PubMed

Kan, Hung-Wei; Chang, Chin-Hong; Lin, Chih-Lung; Lee, Yi-Chen; Hsieh, Sung-Tsang; Hsieh, Yu-Lin

2018-04-16

The neurochemical effects of adenosine signaling in small-fiber neuropathy leading to neuropathic pain are yet to be explored in a direct manner. This study examined this system at the level of ligand (via the ectonucleotidase activity of prostatic acid phosphatase, PAP) and adenosine A1 receptors (A1Rs) in resiniferatoxin (RTX) neuropathy, a peripheral neurodegenerative disorder which specifically affects nociceptive nerves expressing transient receptor potential vanilloid type 1 (TRPV1). We conducted immunohistochemistry on dorsal root ganglion neurons (DRG), high-performance liquid chromatography (HPLC) for functional assays, and pharmacological interventions to alter PAP and A1Rs in mice with RTX neuropathy. In DRG of RTX neuropathy, PAP(+) neurons were reduced compared with vehicle-treated mice (P = 0.002) . Functionally, PAP ectonucleotidase activity was consequently reduced (i.e., the content of adenosine in DRG, P = 0.012). PAP(+) neuronal density was correlated with the degree of mechanical allodynia, which was reversed by intrathecal lumbar puncture (i.t.) injection of recombinant PAP with a dose-dependent effect. Furthermore, A1Rs were downregulated (P = 0.002), and this downregulation was colocalized with the TRPV1 receptor (31.0% ± 2.8%). Mechanical allodynia was attenuated in a dose-dependent response by i.t. injection of the A1R ligand, adenosine; however, no analgesia was evident when an exogenous adenosine was blocked by A1R antagonist. This study demonstrated dual mechanisms of neuropathic pain in TRPV1-induced neuropathy, involving a reduced adenosine system at both the ligand (adenosine) and receptor (A1Rs) levels.

Skeletal lipidomics: regulation of bone metabolism by fatty acid amide family

PubMed Central

Bab, Itai; Smoum, Reem; Bradshaw, Heather; Mechoulam, Raphael

2011-01-01

There is increasing evidence demonstrating that fatty acid derivatives play a key regulatory role in a variety of tissues. However, the study of skeletal lipidomics is just emerging and global strategies, such as targeted lipidomics, have not been applied to bone tissue. Such strategies hold great promises as in the case of genomics and proteomics. A partial profile of endocannabinoids and endocannabinoid-like compounds has demonstrated the presence of several long-chain fatty acid amides (FAAs), some of which displaying potent effects on osteoblasts, the bone forming cells and osteoclasts, the bone resorbing cells. In the skeleton, the FAAs activate the CB1 cannabinoid receptor present in sympathetic nerve terminals as well as CB2 cannabinoid receptor, the Gi-protein coupled receptor GPR55, and the transient receptor potential vanilloid type ion channel expressed by osteoblasts and/or osteoclasts. This review on the skeletal FAA system focuses on the production of FAAs in the skeleton and their net bone anabolic and anti-catabolic activity resulting from the stimulation of bone formation and inhibition of bone resorption. As the FAA family holds great promise as a basis for the treatment of osteoporosis and other diseases involving bone, further studies should aim towards the complete profiling of these lipids and their receptors in bone tissue, followed by elucidation of their function and mechanism of action. LINKED ARTICLES This article is part of a themed issue on Cannabinoids in Biology and Medicine. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.163.issue-7 PMID:21557736

Role of Nonneuronal TRPV4 Signaling in Inflammatory Processes.

PubMed

Rajasekhar, Pradeep; Poole, Daniel P; Veldhuis, Nicholas A

2017-01-01

Transient receptor potential (TRP) ion channels are important signaling components in nociceptive and inflammatory pathways. This is attributed to their ability to function as polymodal sensors of environmental stimuli (chemical and mechanical) and as effector molecules in receptor signaling pathways. TRP vanilloid 4 (TRPV4) is a nonselective cation channel that is activated by multiple endogenous stimuli including shear stress, membrane stretch, and arachidonic acid metabolites. TRPV4 contributes to many important physiological processes and dysregulation of its activity is associated with chronic conditions of metabolism, inflammation, peripheral neuropathies, musculoskeletal development, and cardiovascular regulation. Mechanosensory and receptor- or lipid-mediated signaling functions of TRPV4 have historically been attributed to central and peripheral neurons. However, with the development of potent and selective pharmacological tools, transgenic mice and improved molecular and imaging techniques, many new roles for TRPV4 have been revealed in nonneuronal cells. In this chapter, we discuss these recent findings and highlight the need for greater characterization of TRPV4-mediated signaling in nonneuronal cell types that are either directly associated with neurons or indirectly control their excitability through release of sensitizing cellular factors. We address the integral role of these cells in sensory and inflammatory processes as well as their importance when considering undesirable on-target effects that may be caused by systemic delivery of TRPV4-selective pharmaceutical agents for treatment of chronic diseases. In future, this will drive a need for targeted drug delivery strategies to regulate such a diverse and promiscuous protein. © 2017 Elsevier Inc. All rights reserved.

Mammalian TRPV4 (VR-OAC) directs behavioral responses to osmotic and mechanical stimuli in Caenorhabditis elegans

PubMed Central

Liedtke, Wolfgang; Tobin, David M.; Bargmann, Cornelia I.; Friedman, Jeffrey M.

2003-01-01

All animals detect osmotic and mechanical stimuli, but the molecular basis for these responses is incompletely understood. The vertebrate transient receptor potential channel vanilloid subfamily 4 (TRPV4) (VR-OAC) cation channel has been suggested to be an osmo/mechanosensory channel. To assess its function in vivo, we expressed TRPV4 in Caenorhabditis elegans sensory neurons and examined its ability to generate behavioral responses to sensory stimuli. C. elegans ASH neurons function as polymodal sensory neurons that generate a characteristic escape behavior in response to mechanical, osmotic, or olfactory stimuli. These behaviors require the TRPV channel OSM-9 because osm-9 mutants do not avoid nose touch, high osmolarity, or noxious odors. Expression of mammalian TRPV4 in ASH neurons of osm-9 worms restored avoidance responses to hypertonicity and nose touch, but not the response to odorant repellents. Mutations known to reduce TRPV4 channel activity also reduced its ability to direct nematode avoidance behavior. TRPV4 function in ASH required the endogenous C. elegans osmotic and nose touch avoidance genes ocr-2, odr-3, osm-10, and glr-1, indicating that TRPV4 is integrated into the normal ASH sensory apparatus. The osmotic and mechanical avoidance responses of TRPV4-expressing animals were different in their sensitivity and temperature dependence from the responses of wild-type animals, suggesting that the TRPV4 channel confers its characteristic properties on the transgenic animals' behavior. These results provide evidence that TRPV4 can function as a component of an osmotic/mechanical sensor in vivo. PMID:14581619

Gingerol Reverses the Cancer-Promoting Effect of Capsaicin by Increased TRPV1 Level in a Urethane-Induced Lung Carcinogenic Model.

PubMed

Geng, Shengnan; Zheng, Yaqiu; Meng, Mingjing; Guo, Zhenzhen; Cao, Ning; Ma, Xiaofang; Du, Zhenhua; Li, Jiahuan; Duan, Yongjian; Du, Gangjun

2016-08-10

Both gingerol and capsaicin are agonists of TRPV1, which can negatively control tumor progression. This study observed the long-term effects of oral administration of 6-gingerol alone or in combination with capsaicin for 20 weeks in a urethane-induced lung carcinogenic model. We showed that lung carcinoma incidence and multiplicity were 70% and 21.2 ± 3.6, respectively, in the control versus 100% and 35.6 ± 5.2 in the capsaicin group (P < 0.01) and 50% and 10.8 ± 3.1 in the 6-gingerol group (P < 0.01). The combination of 6-gingerol and capsaicin reversed the cancer-promoting effect of capsaicin (carcinoma incidence of 100% versus 20% and multiplicity of 35.6 ± 5.2 versus 4.7 ± 2.3; P < 0.001). The cancer-promoting effect of capsaicin was due to increased epidermal growth-factor receptor (EGFR) level by decreased transient receptor potential vanilloid type-1 (TRPV1) level (P < 0.01) . The capsaicin-decreased EGFR level subsequently reduced levels of nuclear factor-κB (NF-κB) and cyclin D1 that favored enhanced lung epithelial proliferation and epithelial-mesenchymal transition (EMT) during lung carcinogenesis (P < 0.01). In contrast, 6-gingerol promoted TRPV1 level and drastically decreased the levels of EGFR, NF-κB, and cyclin D1 that favored reduced lung epithelial proliferation and EMT (P < 0.01). This study provides valuable information for the long-term consumption of chili-pepper-rich diets to decrease the risk of cancer development.

Capsaicin-induced reactivation of latent herpes simplex virus type 1 in sensory neurons in culture.

PubMed

Hunsperger, Elizabeth A; Wilcox, Christine L

2003-05-01

Herpes simplex virus type 1 (HSV-1) produces a life-long latent infection in neurons of the peripheral nervous system, primarily in the trigeminal and dorsal root ganglia. Neurons of these ganglia express high levels of the capsaicin receptor, also known as the vanilloid receptor-1 (VR-1). VR-1 is a non-selective ion channel, found on sensory neurons, that primarily fluxes Ca(2+) ions in response to various stimuli, including physiologically acidic conditions, heat greater than 45 degrees C and noxious compounds such as capsaicin. Using an in vitro neuronal model to study HSV-1 latency and reactivation, we found that agonists of the VR-1 channel - capsaicin and heat - resulted in reactivation of latent HSV-1. Capsaicin-induced reactivation of HSV-1 latently infected neurons was dose-dependent. Additionally, activation of VR-1 at its optimal temperature of 46 degrees C caused a significant increase in virus titres, which could be attenuated with the VR-1 antagonist, capsazepine. VR-1 activation that resulted in HSV-1 reactivation was calcium-dependent, since the calcium chelator BAPTA significantly reduced reactivation following treatment with caspsaicin and forskolin. Taken together, these results suggest that activation of the VR-1 channel, often associated with increases in intracellular calcium, results in HSV-1 reactivation in sensory neurons.

[Alternative treatments for interstitial cystitis].

PubMed

Gamé, X; Bart, S; Castel-Lacanal, E; De Sèze, M; Karsenty, G; Labat, J-J; Rigaud, J; Scheiber-Nogueira, M C; Ruffion, A

2009-06-01

Interstitial cystitis is the first cause of bladder pain. In case of failure of the usual treatments, several other modalities have been proposed. These therapeutic modalities are posterior sacral root neuromodulation, posterior tibial nerve stimulation, vanilloid agent intravesical instillation, intradetrusor botulinum toxin injections and surgery. A certain efficiency of each of these treatments in the interstitial cystitis has been reported. However, the evaluation of these treatments is limited and the level of evidence is too low to propose these treatments in routine.

Pharmacological Studies of NOP Receptor Agonists as Novel Analgesics

DTIC Science & Technology

2009-05-01

found in hot-chili peppers that evokes pain sensation by activating at the TRPV1 . TRPV1 and the up-regulation of its expression have been strongly...via nociceptin/orphanin FQ receptors. Br J Pharmacol 137:1355-1361. Knotkova H, Pappagallo M, Szallasi A (2008) Capsaicin ( TRPV1 Agonist) therapy...Szallasi A, Cortright DN, Blum CA, Eid SR (2007). The vanilloid receptor TRPV1 : 10 years from channel cloning to antagonist proof of concept. Nat Rev Drug

Bronchoconstriction induced by hyperventilation with humidified hot air: role of TRPV1-expressing airway afferents.

PubMed

Lin, Ruei-Lung; Hayes, Don; Lee, Lu-Yuan

2009-06-01

A recent study by our laboratory has shown that an increase in intrathoracic temperature activates vagal pulmonary C-fibers. Because these afferents are known to elicit reflex bronchoconstriction upon stimulation, this study was carried out to investigate if an increase in airway temperature within the physiological range alters bronchomotor tone. Adult guinea pigs were anesthetized and mechanically ventilated via a tracheal tube. After the lung had been hyperventilated with humidified hot air (HHA) for 4 min, the tracheal temperature was elevated from 36.4 to 40.5 degrees C, which induced an immediate bronchoconstriction, increasing total pulmonary resistance (R(L)) to 177 +/- 10% and decreasing dynamic lung compliance to 81 +/- 6% of their respective baselines. The increase in R(L) returned spontaneously toward the baseline in <10 min and was reproducible in the same animals. There were no difference in the responses whether the humidity was generated from distilled water or isotonic saline. In contrast, hyperventilation with humidified air at room temperature did not cause any increase in R(L). The increase in R(L) caused by HHA was attenuated by 65.9% after a pretreatment with atropine alone and by 72.0% after a pretreatment with a combination of atropine and neurokinin receptor type 1 and 2 antagonists. In addition, capsazepine, a selective transient receptor potential vanilloid type 1 (TRPV1) antagonist, reduced the HHA-induced increase in R(L) by 64.1% but did not abolish it. However, pretreatment with formoterol, a beta(2)-agonist, completely prevented the HHA-induced bronchoconstriction. These results indicate that the increase in airway temperature induced transient airway constriction in guinea pigs. Approximately two-thirds of the increase in bronchomotor tone was mediated through the cholinergic reflex, which was probably elicited by the activation of TRPV1-expressing airway afferents. The remaining bronchoconstriction was caused by other, yet unidentified factors.

Identification of interleukin-1 beta as a key mediator in the upregulation of Cav3.2–USP5 interactions in the pain pathway

PubMed Central

Stemkowski, Patrick L; Garcia-Caballero, Agustin; Gadotti, Vinicius M; M’Dahoma, Said; Chen, Lina; Souza, Ivana A

2017-01-01

We recently reported that nerve injury or peripheral inflammation triggers an upregulation of the deubiquitinase, USP5 in mouse dorsal root ganglion and spinal dorsal horn. This leads to dysregulated ubiquitination of Cav3.2 T-type calcium channels, thus increasing Cav3.2 channel plasma membrane expression and nociceptive signaling in the primary afferent pain pathway. This phenomenon could be recapitulated by noninvasive, optogenetic activation of transient receptor potential vanilloid-1–expressing nociceptors, indicating that neuronal activity is a key player in this process. Given the relevance of the pro-inflammatory cytokine interleukin-1 beta in many forms of pathological pain, we hypothesized that interleukin-1 beta may be a critical cofactor required to drive upregulation of interactions between USP5 and Cav3.2 channels. Here, we report that gene expression, as well as protein levels for interleukin-1 beta and the endogenous interleukin-1 receptor-I antagonist, IL-1Ra are unaltered following conditioning stimulation of optogenetically targeted cutaneous nociceptors, indicating that neuronal activity is not a driver of interleukin-1 beta signaling. In contrast, co-immunoprecipitation experiments revealed that intrathecal administration of interleukin-1 beta in wild-type mice led to an increase in the interaction between USP5 and Cav3.2 in the spinal dorsal horn. Moreover, disruption of the interaction between USP5 and Cav3.2 with TAT peptides suppressed acute nocifensive responses produced by interleukin-1 beta, which was similar to that achieved by elimination of T-type channel activity with the channel blockers, mibefradil, or TTA-A2. Finally, this upregulation could be maintained in dorsal root ganglion neuron cultures exposed overnight to interleukin-1 beta, while the copresence of interleukin-1 receptor antagonist or the dampening of neuronal cell activity with tetrodotoxin attenuated this response. Altogether, our findings identify interleukin-1 beta as an upstream trigger for the upregulation of interactions between USP5 and Cav3.2 channels in the pain pathway, presumably by triggering increased firing activity in afferent fibers. PMID:28741432

Potential Protective Mechanism in the Cardiac Microvascular Injury.

PubMed

Li, Xiuchuan; Hou, Juanni; Du, Jin; Feng, Jian; Yang, Yi; Shen, Yang; Chen, Sha; Feng, Juan; Yang, Dachun; Li, De; Pei, Haifeng; Yang, Yongjian

2018-05-07

Cardiac microvascular injury often occurs in patients with type 2 diabetes mellitus (T2DM) who develop hyperglycemia and hyperlipidemia. However, besides reported contradictory roles in cardiac diseases, the function of TRPV1 (transient receptor potential vanilloid 1) in cardiac microvessels is not well defined. This study was performed to determine the detailed role of TRPV1 in cardiac microvascular endothelial cells (CMECs) in T2DM. T2DM mice were established by multiple injections of low-dose streptozotocin and high-fat feeding. CMECs were cultured separately in mediums of normal glucose, high glucose (HG), high fatty acid (HF), and HG plus HF (HG-HF). HG-HF inhibited TRPV1 expression in CMECs, reducing cellular Ca 2+ content ([Ca 2+ ] i ). T2DM impaired cardiac function, disturbed glucose uptake, and damaged microvascular barrier, which were further aggravated by TRPV1 -/- Exposure to HG-HF, particularly in TRPV1 -/- CMECs, led to a higher level of apoptosis and a lower level of nitric oxide production in viable CMECs. HG-HF markedly enhanced generation of reactive oxygen species and nitrotyrosine, especially in the absence of TRPV1. H 2 O 2 administration reduced TRPV1 expression in CMECs. HG-HF significantly depressed expression of PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α) and OPA1 (optic atrophy 1) by reducing [Ca 2+ ] i , whereas OPA1 supplementation partly reversed those detrimental effects induced by TRPV1 -/- Furthermore, capsaicin treatment not only attenuated CMECs injury induced by HG-HF but also mitigated cardiac microvascular injury induced by T2DM. Collectively, T2DM leads to cardiac microvascular injury by exacerbating the vicious circle of TRPV1 blockage and reactive oxygen species overload. Long-term capsaicin can protect cardiac microvessels against T2DM via suppressing oxidative/nitrative stress mediated by TRPV1/Ca 2+ /PGC-1α/OPA1 pathway in CMECs. © 2018 American Heart Association, Inc.

The role of calbindin-D28k on renal calcium and magnesium handling during treatment with loop and thiazide diuretics

PubMed Central

Lee, Chien-Te; Ng, Hwee-Yeong; Lee, Yueh-Ting; Lai, Li-Wen

2015-01-01

Calbindin-D28k (CBD-28k) is a calcium binding protein located in the distal convoluted tubule (DCT) and plays an important role in active calcium transport in the kidney. Loop and thiazide diuretics affect renal Ca and Mg handling: both cause Mg wasting, but have opposite effects on Ca excretion as loop diuretics increase, but thiazides decrease, Ca excretion. To understand the role of CBD-28k in renal Ca and Mg handling in response to diuretics treatment, we investigated renal Ca and Mg excretion and gene expression of DCT Ca and Mg transport molecules in wild-type (WT) and CBD-28k knockout (KO) mice. Mice were treated with chlorothiazide (CTZ; 50 mg·kg−1·day−1) or furosemide (FSM; 30 mg·kg−1·day−1) for 3 days. To avoid volume depletion, salt was supplemented in the drinking water. Urine Ca excretion was reduced in WT, but not in KO mice, by CTZ. FSM induced similar hypercalciuria in both groups. DCT Ca transport molecules, including transient receptor potential vanilloid 5 (TRPV5), TRPV6, and CBD-9k, were upregulated by CTZ and FSM in WT, but not in KO mice. Urine Mg excretion was increased and transient receptor potential subfamily M, member 6 (TRPM6) was upregulated by both CTZ and FSM in WT and KO mice. In conclusion, CBD-28k plays an important role in gene expression of DCT Ca, but not Mg, transport molecules, which may be related to its being a Ca, but not a Mg, intracellular sensor. The lack of upregulation of DCT Ca transport molecules by thiazides in the KO mice indicates that the DCT Ca transport system is critical for Ca conservation by thiazides. PMID:26582761

Parathyroid Hormone-Related Peptide Elicits Peripheral TRPV1-dependent Mechanical Hypersensitivity

PubMed Central

Shepherd, Andrew J.; Mickle, Aaron D.; Kadunganattil, Suraj; Hu, Hongzhen; Mohapatra, Durga P.

2018-01-01

Bone metastasis in breast, prostate and lung cancers often leads to chronic pain, which is poorly managed by existing analgesics. The neurobiological mechanisms that underlie chronic pain associated with bone-metastasized cancers are not well understood, but sensitization of peripheral nociceptors by tumor microenvironment factors has been demonstrated to be important. Parathyroid hormone-related peptide (PTHrP) is highly expressed in bone-metastasized breast and prostate cancers, and is critical to growth and proliferation of these tumors in the bone tumor microenvironment. Previous studies have suggested that PTHrP could sensitize nociceptive sensory neurons, resulting in peripheral pain hypersensitivity. In this study, we found that PTHrP induces both heat and mechanical hypersensitivity, that are dependent on the pain-transducing transient receptor potential channel family vanilloid, member-1 (TRPV1), but not the mechano-transducing TRPV4 and TRPA1 ion channels. Functional ratiometric Ca2+ imaging and voltage-clamp electrophysiological analysis of cultured mouse DRG neurons show significant potentiation of TRPV1, but not TRPA1 or TRPV4 channel activation by PTHrP. Interestingly, PTHrP exposure led to the slow and sustained activation of TRPV1, in the absence of any exogenous channel agonist, and is dependent on the expression of the type-1 parathyroid hormone receptor (PTH1), as well as on downstream phosphorylation of the channel by protein kinase C (PKC). Accordingly, local administration of specific small-molecule antagonists of TRPV1 to mouse hindpaws after the development of PTHrP-induced mechanical hypersensitivity led to its significant attenuation. Collectively, our findings suggest that PTHrP/PTH1-mediated flow activation of TRPV1 channel contributes at least in part to the development and maintenance of peripheral mechanical pain hypersensitivity, and could therefore constitute a mechanism for nociceptor sensitization in the context of metastatic bone cancer pain. PMID:29497363

Implication of the ryanodine receptor in TRPV4-induced calcium response in pulmonary arterial smooth muscle cells from normoxic and chronically hypoxic rats.

PubMed

Dahan, Diana; Ducret, Thomas; Quignard, Jean-François; Marthan, Roger; Savineau, Jean-Pierre; Estève, Eric

2012-11-01

There is a growing body of evidence indicating that transient receptor potential (TRP) channels are implicated in calcium signaling and various cellular functions in the pulmonary vasculature. The aim of this study was to investigate the expression, functional role, and coupling to reticulum calcium channels of the type 4 vanilloid TRP subfamily (TRPV4) in the pulmonary artery from both normoxic (Nx) and chronically hypoxic (CH) rats. Activation of TRPV4 with the specific agonist 4α-phorbol-12,13-didecanoate (4α-PDD, 5 μM) increased the intracellular calcium concentration ([Ca(2+)](i)). This effect was significantly reduced by a high concentration of ryanodine (100 μM) or chronic caffeine (5 mM) that blocked ryanodine receptor (RyR) but was insensitive to xestospongin C (10 μM), an inositol trisphosphate receptor antagonist. Inhibition of RyR1 and RyR3 only with 10 μM of dantrolene did not attenuate the 4α-PDD-induced [Ca(2+)](i) increase. Western blotting experiments revealed the expression of TRPV4 and RyR2 with an increase in both receptors in pulmonary arteries from CH rats vs. Nx rats. Accordingly, the 4α-PDD-activated current, measured with patch-clamp technique, was increased in pulmonary artery smooth muscle cells (PASMC) from CH rats vs. Nx rats. 4α-PDD increased isometric tension in artery rings, and this response was also potentiated under chronic hypoxia conditions. 4α-PDD-induced calcium response, current, and contraction were all inhibited by the selective TRPV4 blocker HC-067047. Collectively, our findings provide evidence of the interplay between TRPV4 and RyR2 in the Ca(2+) release mechanism and contraction in PASMC. This study provides new insights onto the complex calcium signaling in PASMC and point out the importance of the TRPV4-RyR2 signaling pathway under hypoxic conditions that may lead to pulmonary hypertension.

Cannabidiol: pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders.

PubMed

Devinsky, Orrin; Cilio, Maria Roberta; Cross, Helen; Fernandez-Ruiz, Javier; French, Jacqueline; Hill, Charlotte; Katz, Russell; Di Marzo, Vincenzo; Jutras-Aswad, Didier; Notcutt, William George; Martinez-Orgado, Jose; Robson, Philip J; Rohrback, Brian G; Thiele, Elizabeth; Whalley, Benjamin; Friedman, Daniel

2014-06-01

To present a summary of current scientific evidence about the cannabinoid, cannabidiol (CBD) with regard to its relevance to epilepsy and other selected neuropsychiatric disorders. We summarize the presentations from a conference in which invited participants reviewed relevant aspects of the physiology, mechanisms of action, pharmacology, and data from studies with animal models and human subjects. Cannabis has been used to treat disease since ancient times. Δ(9) -Tetrahydrocannabinol (Δ(9) -THC) is the major psychoactive ingredient and CBD is the major nonpsychoactive ingredient in cannabis. Cannabis and Δ(9) -THC are anticonvulsant in most animal models but can be proconvulsant in some healthy animals. The psychotropic effects of Δ(9) -THC limit tolerability. CBD is anticonvulsant in many acute animal models, but there are limited data in chronic models. The antiepileptic mechanisms of CBD are not known, but may include effects on the equilibrative nucleoside transporter; the orphan G-protein-coupled receptor GPR55; the transient receptor potential of vanilloid type-1 channel; the 5-HT1a receptor; and the α3 and α1 glycine receptors. CBD has neuroprotective and antiinflammatory effects, and it appears to be well tolerated in humans, but small and methodologically limited studies of CBD in human epilepsy have been inconclusive. More recent anecdotal reports of high-ratio CBD:Δ(9) -THC medical marijuana have claimed efficacy, but studies were not controlled. CBD bears investigation in epilepsy and other neuropsychiatric disorders, including anxiety, schizophrenia, addiction, and neonatal hypoxic-ischemic encephalopathy. However, we lack data from well-powered double-blind randomized, controlled studies on the efficacy of pure CBD for any disorder. Initial dose-tolerability and double-blind randomized, controlled studies focusing on target intractable epilepsy populations such as patients with Dravet and Lennox-Gastaut syndromes are being planned. Trials in other treatment-resistant epilepsies may also be warranted. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

The multiplicity of spinal AA-5-HT anti-nociceptive action in a rat model of neuropathic pain.

PubMed

Malek, Natalia; Kostrzewa, Magdalena; Makuch, Wioletta; Pajak, Agnieszka; Kucharczyk, Mateusz; Piscitelli, Fabiana; Przewlocka, Barbara; Di Marzo, Vincenzo; Starowicz, Katarzyna

2016-09-01

There is considerable evidence to support the role of anandamide (AEA), an endogenous ligand of cannabinoid receptors, in neuropathic pain modulation. AEA also produces effects mediated by other biological targets, of which the transient receptor potential vanilloid type 1 (TRPV1) has been the most investigated. Both, inhibition of AEA breakdown by fatty acid amide hydrolase (FAAH) and blockage of TRPV1 have been shown to produce anti-nociceptive effects. Recent research suggests the usefulness of dual-action compounds, which may afford greater anti-allodynic efficacy. Therefore, in the present study, we examined the effect of N-arachidonoyl-serotonin (AA-5-HT), a blocker of FAAH and TRPV1, in a rat model of neuropathic pain after intrathecal administration. We found that treatment with AA-5-HT increased the pain threshold to mechanical and thermal stimuli, with highest effect at the dose of 500nM, which was most strongly attenuated by AM-630, CB2 antagonist, administration. The single action blockers PF-3845 (1000nM, for FAAH) and I-RTX (1nM, for TRPV1) showed lower efficacy than AA-5-HT. Moreover AA-5-HT (500nM) elevated AEA and palmitoylethanolamide (PEA) levels. Among the possible targets of these mediators, only the mRNA levels of CB2, GPR18 and GPR55, which are believed to be novel cannabinoid receptors, were upregulated in the spinal cord and/or DRG of CCI rats. It was previously reported that AA-5-HT acts in CB1 and TRPV1-dependent manner after systemic administration, but here for the first time we show that AA-5-HT action at the spinal level involves CB2, with potential contributions from GRP18 and/or GPR55 receptors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Role of cationic channel TRPV2 in promoting prostate cancer migration and progression to androgen resistance.

PubMed

Monet, Michaël; Lehen'kyi, V'yacheslav; Gackiere, Florian; Firlej, Virginie; Vandenberghe, Matthieu; Roudbaraki, Morad; Gkika, Dimitra; Pourtier, Albin; Bidaux, Gabriel; Slomianny, Christian; Delcourt, Philippe; Rassendren, François; Bergerat, Jean-Pierre; Ceraline, Jocelyn; Cabon, Florence; Humez, Sandrine; Prevarskaya, Natalia

2010-02-01

Castration resistance in prostate cancer (PCa) constitutes an advanced, aggressive disease with poor prognosis, associated with uncontrolled cell proliferation, resistance to apoptosis, and enhanced invasive potential. The molecular mechanisms involved in the transition of PCa to castration resistance are obscure. Here, we report that the nonselective cationic channel transient receptor potential vanilloid 2 (TRPV2) is a distinctive feature of castration-resistant PCa. TRPV2 transcript levels were higher in patients with metastatic cancer (stage M1) compared with primary solid tumors (stages T2a and T2b). Previous studies of the TRPV2 channel indicated that it is primarily involved in cancer cell migration and not in cell growth. Introducing TRPV2 into androgen-dependent LNCaP cells enhanced cell migration along with expression of invasion markers matrix metalloproteinase (MMP) 9 and cathepsin B. Consistent with the likelihood that TRPV2 may affect cancer cell aggressiveness by influencing basal intracellular calcium levels, small interfering RNA-mediated silencing of TRPV2 reduced the growth and invasive properties of PC3 prostate tumors established in nude mice xenografts, and diminished expression of invasive enzymes MMP2, MMP9, and cathepsin B. Our findings establish a role for TRPV2 in PCa progression to the aggressive castration-resistant stage, prompting evaluation of TRPV2 as a potential prognostic marker and therapeutic target in the setting of advanced PCa.

An orally active TRPV4 channel blocker prevents and resolves pulmonary edema induced by heart failure.

PubMed

Thorneloe, Kevin S; Cheung, Mui; Bao, Weike; Alsaid, Hasan; Lenhard, Stephen; Jian, Ming-Yuan; Costell, Melissa; Maniscalco-Hauk, Kristeen; Krawiec, John A; Olzinski, Alan; Gordon, Earl; Lozinskaya, Irina; Elefante, Lou; Qin, Pu; Matasic, Daniel S; James, Chris; Tunstead, James; Donovan, Brian; Kallal, Lorena; Waszkiewicz, Anna; Vaidya, Kalindi; Davenport, Elizabeth A; Larkin, Jonathan; Burgert, Mark; Casillas, Linda N; Marquis, Robert W; Ye, Guosen; Eidam, Hilary S; Goodman, Krista B; Toomey, John R; Roethke, Theresa J; Jucker, Beat M; Schnackenberg, Christine G; Townsley, Mary I; Lepore, John J; Willette, Robert N

2012-11-07

Pulmonary edema resulting from high pulmonary venous pressure (PVP) is a major cause of morbidity and mortality in heart failure (HF) patients, but current treatment options demonstrate substantial limitations. Recent evidence from rodent lungs suggests that PVP-induced edema is driven by activation of pulmonary capillary endothelial transient receptor potential vanilloid 4 (TRPV4) channels. To examine the therapeutic potential of this mechanism, we evaluated TRPV4 expression in human congestive HF lungs and developed small-molecule TRPV4 channel blockers for testing in animal models of HF. TRPV4 immunolabeling of human lung sections demonstrated expression of TRPV4 in the pulmonary vasculature that was enhanced in sections from HF patients compared to controls. GSK2193874 was identified as a selective, orally active TRPV4 blocker that inhibits Ca(2+) influx through recombinant TRPV4 channels and native endothelial TRPV4 currents. In isolated rodent and canine lungs, TRPV4 blockade prevented the increased vascular permeability and resultant pulmonary edema associated with elevated PVP. Furthermore, in both acute and chronic HF models, GSK2193874 pretreatment inhibited the formation of pulmonary edema and enhanced arterial oxygenation. Finally, GSK2193874 treatment resolved pulmonary edema already established by myocardial infarction in mice. These findings identify a crucial role for TRPV4 in the formation of HF-induced pulmonary edema and suggest that TRPV4 blockade is a potential therapeutic strategy for HF patients.

PKCepsilon-dependent potentiation of TTX-resistant Nav1.8 current by neurokinin-1 receptor activation in rat dorsal root ganglion neurons.

PubMed

Cang, Chun-Lei; Zhang, Hua; Zhang, Yu-Qiu; Zhao, Zhi-Qi

2009-06-30

Substance P (SP), which mainly exists in a subtype of small-diameter dorsal root ganglion (DRG) neurons, is an important signal molecule in pain processing in the spinal cord. Our previous results have proved the expression of SP receptor neurokinin-1 (NK-1) on DRG neurons and its interaction with transient receptor potential vanilloid 1 (TRPV1) receptor. In this study we investigated the effect of NK-1 receptor agonist on Na(v)1.8, a tetrodotoxin (TTX)-resistant sodium channel, in rat small-diameter DRG neurons employing whole-cell patch clamp recordings. NK-1 agonist [Sar(9), Met(O2)(11)]-substance P (Sar-SP) significantly enhanced the Na(v)1.8 currents in a subgroup of small-diameter DRG neurons under both the normal and inflammatory situation, and the enhancement was blocked by NK-1 antagonist Win51708 and protein kinase C (PKC) inhibitor bisindolylmaleimide (BIM), but not the protein kinase A (PKA) inhibitor H89. In particular, the inhibitor of PKCepsilon, a PKC isoform, completely blocked this effect. Under current clamp model, Sar-SP reduced the amount of current required to evoke action potentials and increased the firing rate in a subgroup of DRG neurons. These data suggest that activation of NK-1 receptor potentiates Na(v)1.8 sodium current via PKCepsilon-dependent signaling pathway, probably participating in the generation of inflammatory hyperalgesia.

Potential of Endocannabinoids to Control Bladder Pain.

PubMed

Bjorling, Dale E; Wang, Zun-Yi

2018-01-01

Bladder-related pain is one of the most common forms of visceral pain, and visceral pain is among the most common complaints for which patients seek physician consultation. Despite extensive studies of visceral innervation and treatment of visceral pain, opioids remain a mainstay for management of bladder pain. Side effects associated with opioid therapy can profoundly diminish quality of life, and improved options for treatment of bladder pain remain a high priority. Endocannabinoids, primarily anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are endogenously-produced fatty acid ethanolamides with that induce analgesia. Animal experiments have demonstrated that inhibition of enzymes that degrade AEA or 2-AG have the potential to prevent development of visceral and somatic pain. Although experimental results in animal models have been promising, clinical application of this approach has proven difficult. In addition to fatty acid amide hydrolase (FAAH; degrades AEA) and monacylglycerol lipase (MAGL; degrades 2-AG), cyclooxygenase (COX) acts to metabolize endocannabinoids. Another potential limitation of this strategy is that AEA activates pro-nociceptive transient receptor potential vanilloid 1 (TRPV1) channels. Dual inhibitors of FAAH and TRPV1 or FAAH and COX have been synthesized and are currently undergoing preclinical testing for efficacy in providing analgesia. Local inhibition of FAAH or MAGL within the bladder may be viable options to reduce pain associated with cystitis with fewer systemic side effects, but this has not been explored. Further investigation is required before manipulation of the endocannabinoid system can be proven as an efficacious alternative for management of bladder pain.

The mucosal surfaces of both eyes are immunologically linked by a neurogenic inflammatory reflex involving TRPV1 and substance P.

PubMed

Guzmán, Mauricio; Miglio, Maximiliano S; Zgajnar, Nadia R; Colado, Ana; Almejún, María B; Keitelman, Irene A; Sabbione, Florencia; Fuentes, Federico; Trevani, Analía S; Giordano, Mirta N; Galletti, Jeremías G

2018-06-04

Immunological interdependence between the two eyes has been reported for the cornea and the retina but not for the ocular mucosal surface. Intriguingly, patients frequently report ocular surface-related symptoms in the other eye after unilateral ocular surgery. Here we show how unilateral eye injuries in mice affect the mucosal immune response of the opposite ocular surface. We report that, despite the lack of lymphatic cross-drainage, a neurogenic inflammatory reflex in the contralateral conjunctiva is sufficient to increase, first, epithelial nuclear factor kappa B signaling, then, dendritic cell maturation, and finally, expansion of effector, instead of regulatory, T cells in the draining lymph node, leading to disrupted ocular mucosal tolerance. We also show that damage to ocular surface nerves is required. Using pharmacological inhibitors and agonists, we identified transient receptor potential vanilloid 1 (TRPV1) channel as the receptor sensing tissue damage in the injured eye and substance P released in the opposite ocular surface as the effector of the sympathetic response. Finally, blocking either step prevented subsequent ocular allergic reactions in the opposite eye in a unilateral corneal alkali burn model. This study demonstrates that both ocular surfaces are immunologically linked and suggests potential therapeutic targets for intervention.

TRPV6 calcium channel translocates to the plasma membrane via Orai1-mediated mechanism and controls cancer cell survival

PubMed Central

Raphaël, Maylis; Lehen’kyi, V’yacheslav; Vandenberghe, Matthieu; Beck, Benjamin; Khalimonchyk, Sergiy; Vanden Abeele, Fabien; Farsetti, Leonardo; Germain, Emmanuelle; Bokhobza, Alexandre; Mihalache, Adriana; Gosset, Pierre; Romanin, Christoph; Clézardin, Philippe; Skryma, Roman; Prevarskaya, Natalia

2014-01-01

Transient receptor potential vanilloid subfamily member 6 (TRPV6) is a highly selective calcium channel that has been considered as a part of store-operated calcium entry (SOCE). Despite its first discovery in the early 2000s, the role of this channel in prostate cancer (PCa) remained, until now, obscure. Here we show that TRPV6 mediates calcium entry, which is highly increased in PCa due to the remodeling mechanism involving the translocation of the TRPV6 channel to the plasma membrane via the Orai1/TRPC1-mediated Ca2+/Annexin I/S100A11 pathway, partially contributing to SOCE. The TRPV6 calcium channel is expressed de novo by the PCa cell to increase its survival by enhancing proliferation and conferring apoptosis resistance. Xenografts in nude mice and bone metastasis models confirmed the remarkable aggressiveness of TRPV6-overexpressing tumors. Immunohistochemical analysis of these demonstrated the increased expression of clinical markers such as Ki-67, prostate specific antigen, synaptophysin, CD31, and CD56, which are strongly associated with a poor prognosis. Thus, the TRPV6 channel acquires its oncogenic potential in PCa due to the remodeling mechanism via the Orai1-mediated Ca2+/Annexin I/S100A11 pathway. PMID:25172921

Neutral endopeptidase determines the severity of pancreatitis-associated lung injury.

PubMed

Day, Amy Lightner; Wick, Elizabeth; Jordan, Thomas H; Jaffray, Colleen E; Bunnett, Nigel W; Grady, Eileen F; Kirkwood, Kimberly S

2005-09-01

Neutral endopeptidase (NEP) is a cell-surface metalloprotease that degrades proinflammatory peptides such as substance P, neurokinin A, and bradykinin. Inhibition of NEP exacerbates both experimental pancreatitis and the associated lung injury. It is unclear if worsened lung injury is the indirect result of more severe pancreatitis or if it is a direct effect of NEP inhibition in the lung. We used a model of pancreatitis-associated lung injury (PALI) to test the hypothesis that antagonism or genetic deletion of NEP augments PALI inflammation and pulmonary damage irregardless of the degree of pancreatitic inflammation. In NEP(+/+) mice, intraperitoneal injection of porcine pancreatic elastase (elastase, 0.085 U/g at t = 0 h and t = 1 h) caused a 7-fold increase in lung myeloperoxidase (MPO) activity and marked pulmonary edema, neutrophil infiltration, and hemorrhage at 4 h as compared to control animals. The pattern of lung injury induced by elastase mimicked that observed among a separate group of animals with PALI induced by cerulein but was not associated with pancreatitis. Both NEP(-/-) mice and NEP(+/+) mice pretreated with the NEP antagonist phosphoramidon (10 mg/kg s.c.) had significant elevations of lung MPO and worsened lung histology compared to NEP(+/+) mice given elastase alone. Antagonism of either the vanilloid receptor transient receptor vanilloid 1 or the substance P receptor NK1-R had no effect on elastase-mediated lung injury in NEP-deficient mice. NEP is an inhibitor of pancreatic elastase-induced lung injury, presumably via degradation of proinflammatory mediators.

Ontogenetic expression of the vanilloid receptors TRPV1 and TRPV2 in the rat retina.

PubMed

Leonelli, Mauro; Martins, Daniel O; Kihara, Alexandre H; Britto, Luiz R G

2009-11-01

The present study aimed to analyze the gene and protein expression and the pattern of distribution of the vanilloid receptors TRPV1 and TRPV2 in the developing rat retina. During the early phases of development, TRPV1 was found mainly in the neuroblastic layer of the retina and in the pigmented epithelium. In the adult, TRPV1 was found in microglial cells, blood vessels, astrocytes and in neuronal structures, namely synaptic boutons of both retinal plexiform layers, as well as in cell bodies of the inner nuclear layer and the ganglion cell layer. The pattern of distribution of TRPV1 was mainly punctate, and there was higher TRPV1 labeling in the peripheral retina than in central regions. TRPV2 expression was quite distinct. Its expression was virtually undetectable by immunoblotting before P1, and that receptor was found by immunohistochemistry only by postnatal day 15 (P15). RNA and protein analysis showed that the adult levels are only reached by P60, which includes small processes in the retinal plexiform layers, and labeled cellular bodies in the inner nuclear layer and the ganglion cell layer. There was no overlapping between the signal observed for both receptors. In conclusion, our results showed that the patterns of distribution of TRPV1 and TRPV2 are different during the development of the rat retina, suggesting that they have specific roles in both visual processing and in providing specific cues to neural development.

Mechanisms involved in oleamide-induced vasorelaxation in rat mesenteric resistance arteries.

PubMed

Sudhahar, Varadarajan; Shaw, Sean; Imig, John D

2009-04-01

Fatty acid amides are a new class of signaling lipids that have been implicated in diverse physiological and pathological conditions. Oleamide is a fatty acid amide that induces vasorelaxation. Here, we investigated the mechanisms behind the vasorelaxation effect of oleamide in rat mesenteric resistance arteries. Oleamide-induced concentration dependent (0.01 microM-10 microM) vasorelaxation in mesenteric resistance arteries. This relaxation was unaffected by the presence of the fatty acid amide hydrolase (FAAH) inhibitors. The cannabinoid type 1 (CB1) receptor antagonist, AM251 and the non-CB1/CB2 cannabinoid receptor antagonist, O-1918, attenuated the oleamide vasodilatory response, however the cannabinoid CB2 receptor antagonist, AM630, did not affect the vascular response. Moreover, inhibition of the transient receptor potential vanilloid (TRPV) 1 receptor with capsazepine shifted the oleamide-induced vasorelaxation response to the right. In agreement with the vascular functional data, the cannabinoid CB1 and TRPV1 receptor proteins were expressed in mesenteric resistance arteries but cannabinoid CB2 receptors and the FAAH enzyme were not. In endothelium-denuded arteries, the oleamide-mediated vasorelaxation was attenuated and cannabinoid CB1 or non-CB1/CB2 cannabinoid receptor blockade did not further reduce the dilatory response whereas TRPV1 antagonism further decreased the response. These findings indicate that cannabinoid receptors on the endothelium and endothelium-independent TRPV1 receptors contribute to the oleamide vasodilatory response. Taken together, these results demonstrate that the oleamide-induced vasorelaxation is mediated, in part, by cannabinoid CB1 receptors, non-CB1/CB2 cannabinoid receptors, and TRPV1 receptors in rat mesenteric resistance arteries. These mechanisms are overlapping in respect to oleamide-induced mesenteric resistance artery dilation.

Mechanisms involved in oleamide-induced vasorelaxation in rat mesenteric resistance arteries

PubMed Central

Sudhahar, Varadarajan; Shaw, Sean; Imig, John D.

2009-01-01

Fatty acid amides are a new class of signaling lipids that have been implicated in diverse physiological and pathological conditions. Oleamide is a fatty acid amide that induces vasorelaxation. Here, we investigated the mechanisms behind the vasorelaxation effect of oleamide in rat mesenteric resistance arteries. Oleamide-induced concentration dependent (0.01 μM–10μM) vasorelaxation in mesenteric resistance arteries. This relaxation was unaffected by the presence of the fatty acid amide hydrolase (FAAH) inhibitors. The cannabinoid type 1 (CB1) receptor antagonist, AM251 and the non-CB1/CB2 cannabinoid receptor antagonist, O-1918, attenuated the oleamide vasodilatory response, however the cannabinoid CB2 receptor antagonist, AM630, did not affect the vascular response. Moreover, inhibition of the transient receptor potential vanilloid (TRPV) 1 receptor with capsazepine shifted the oleamide-induced vasorelaxation response to the right. In agreement with the vascular functional data, the cannabinoid CB1 and TRPV1 receptor proteins were expressed in mesenteric resistance arteries but cannabinoid CB2 receptors and the FAAH enzyme were not. In endothelium-denuded arteries, the oleamide-mediated vasorelaxation was attenuated and cannabinoid CB1 or non-CB1/CB2 cannabinoid receptor blockade did not further reduce the dilatory response whereas TRPV1 antagonism further decreased the response. These findings indicate that cannabinoid receptors on the endothelium and endothelium-independent TRPV1 receptors contribute to the oleamide vasodilatory response. Taken together, these results demonstrate that the oleamide-induced vasorelaxation is mediated, in part, by cannabinoid CB1 receptors, non-CB1/CB2 cannabinoid receptors, and TRPV1 receptors in rat mesenteric resistance arteries. These mechanisms are overlapping in respect to oleamide-induced mesenteric resistance artery dilation. PMID:19326479

α1- and α2-Adrenergic responsiveness in human skeletal muscle feed arteries: the role of TRPV ion channels in heat-induced sympatholysis

PubMed Central

Gifford, Jayson R.; Ives, Stephen J.; Park, Song-Young; Andtbacka, Robert H. I.; Hyngstrom, John R.; Mueller, Michelle T.; Treiman, Gerald S.; Ward, Christopher; Trinity, Joel D.

2014-01-01

The purpose of this study was to determine if heat inhibits α2-adrenergic vasocontraction, similarly to α1-adrenergic contraction, in isolated human skeletal muscle feed arteries (SMFA) and elucidate the role of the temperature-sensitive vanilloid-type transient receptor potential (TRPV) ion channels in this response. Isolated SMFA from 37 subjects were studied using wire myography. α1 [Phenylephrine (PE)]- and α2 [dexmedetomidine (DEX)]-contractions were induced at 37 and 39°C with and without TRPV family and TRPV4-specific inhibition [ruthenium red (RR) and RN-1734, respectively]. Endothelial function [acetylcholine (ACh)] and smooth muscle function [sodium nitroprusside (SNP) and potassium chloride (KCl)] were also assessed under these conditions. Heat and TRPV inhibition was further examined in endothelium-denuded arteries. Contraction data are reported as a percentage of maximal contraction elicited by 100 mM KCl (LTmax). DEX elicited a small and variable contractile response, one-fifth the magnitude of PE, which was not as clearly attenuated when heated from 37 to 39°C (12 ± 4 to 6 ± 2% LTmax; P = 0.18) as were PE-induced contractions (59 ± 5 to 24 ± 4% LTmax; P < 0.05). Both forms of TRPV inhibition restored PE-induced contraction at 39°C (P < 0.05) implicating these channels, particularly the TRPV4 channels, in the heat-induced attenuation of α1-adrenergic vasocontraction. TRPV inhibition significantly blunted ACh relaxation while denudation prevented heat-induced sympatholysis without having an additive effect when combined with TRPV inhibition. In conclusion, physiological increases in temperature elicit a sympatholysis-like inhibition of α1-adrenergic vasocontraction in human SMFA that appears to be mediated by endothelial TRPV4 ion channels. PMID:25172894

Immunolocalization and distribution of functional temperature-sensitive TRP channels in salivary glands.

PubMed

Sobhan, Ubaidus; Sato, Masaki; Shinomiya, Takashi; Okubo, Migiwa; Tsumura, Maki; Muramatsu, Takashi; Kawaguchi, Mitsuru; Tazaki, Masakazu; Shibukawa, Yoshiyuki

2013-11-01

Transient receptor potential (TRP) cation channels are unique cellular sensors involved in multiple cellular functions. Their role in salivary secretion remains to be elucidated. The expression and localization of temperature-sensitive TRP channels in salivary (submandibular, sublingual and parotid) glands were analyzed by immunohistochemistry and quantitative real-time reverse transcription plus the polymerase chain reaction (RT-PCR). The effects of various TRP channel agonists on carbachol (CCh)-induced salivary secretion in the submandibular gland and on the intracellular Ca(2+) concentration ([Ca(2+)]i) in a submandibular epithelial cell line were also investigated. Immunohistochemistry revealed the expression of TRP-melastatin subfamily member 8 (TRPM8) and TRP-ankyrin subfamily member 1 (TRPA1) in myoepithelial, acinar and ductal cells in the sublingual, submandibular and parotid glands. In addition, TRP-vanilloid subfamily member 1 (TRPV1), TRPV3 and TRPV4 were also expressed in myoepithelial, acinar and ductal cells in all three types of gland. Quantitative real-time RT-PCR results demonstrated the mRNA expression of TRPV1, TRPV3, TRPV4, TRPM8 and TRPA1 in acinar and ductal cells in these salivary glands. Perfusion of the entire submandibular gland with the TRPV1 agonist capsaicin (1 μM) via the submandibular artery significantly increased CCh-induced salivation, whereas perfusion with TRPM8 and TRPA1 agonists (0.5 μM WS12 and 100 μM allyl isothiocyanate) decreased it. Application of agonists for each of the thermosensitive TRP channels increased [Ca(2+)]i in a submandibular epithelial cell line. These results indicate that temperature-sensitive TRP channels are localized and distributed in acinar, ductal and myoepithelial cells in salivary glands and that they play a functional role in the regulation and/or modulation of salivary secretion.

Mitochondrial modulation-induced activation of vagal sensory neuronal subsets by antimycin A, but not CCCP or rotenone, correlates with mitochondrial superoxide production.

PubMed

Stanford, Katherine R; Taylor-Clark, Thomas E

2018-01-01

Inflammation causes nociceptive sensory neuron activation, evoking debilitating symptoms and reflexes. Inflammatory signaling pathways are capable of modulating mitochondrial function, resulting in reactive oxygen species (ROS) production, mitochondrial depolarization and calcium release. Previously we showed that mitochondrial modulation with antimycin A, a complex III inhibitor, selectively stimulated nociceptive bronchopulmonary C-fibers via the activation of transient receptor potential (TRP) ankyrin 1 (A1) and vanilloid 1 (V1) cation channels. TRPA1 is ROS-sensitive, but there is little evidence that TRPV1 is activated by ROS. Here, we used dual imaging of dissociated vagal neurons to investigate the correlation of mitochondrial superoxide production (mitoSOX) or mitochondrial depolarization (JC-1) with cytosolic calcium (Fura-2AM), following mitochondrial modulation by antimycin A, rotenone (complex I inhibitor) and carbonyl cyanide m-chlorophenyl hydrazone (CCCP, mitochondrial uncoupling agent). Mitochondrial modulation by all agents selectively increased cytosolic calcium in a subset of TRPA1/TRPV1-expressing (A1/V1+) neurons. There was a significant correlation between antimycin A-induced calcium responses and mitochondrial superoxide in wild-type 'responding' A1/V1+ neurons, which was eliminated in TRPA1-/- neurons, but not TRPV1-/- neurons. Nevertheless, antimycin A-induced superoxide production did not always increase calcium in A1/V1+ neurons, suggesting a critical role of an unknown factor. CCCP caused both superoxide production and mitochondrial depolarization but neither correlated with calcium fluxes in A1/V1+ neurons. Rotenone-induced calcium responses in 'responding' A1/V1+ neurons correlated with mitochondrial depolarization but not superoxide production. Our data are consistent with the hypothesis that mitochondrial dysfunction causes calcium fluxes in a subset of A1/V1+ neurons via ROS-dependent and ROS-independent mechanisms.

Analgesic effects elicited by neuroactive mediators injected into the ST 36 acupuncture point on inflammatory and neuropathic pain in mice.

PubMed

Vieira, Jadina Santos; Toreti, Jéssica Aline; Carvalho, Ravena Carolina de; de Araújo, João Eduardo; Silva, Marcelo Lourenço; Silva, Josie Resende Torres

2018-05-31

The present study evaluates whether the injection of serotonin, acetylcholine, glutamate, bradykinin, histamine or substance P into the Zusanli (Stomach 36, ST 36) acupoint can also produce the acupuncture-induced antinociceptive effect on inflammatory or neuropathic pain. In this in vivo experimental study a total of 450 male Swiss mice were used. Mice were injected with saline or complete Freund's adjuvant (CFA) or subjected to sham or chronic constriction injury (CCI) surgery. After the establishment of the inflammatory (4 hours) or the neuropathic pain (3 days) the animals (n=6) received manual acupuncture (MA), sham acupuncture (OUT) or injection of saline, serotonin, acetylcholine, glutamate, bradykinin, histamine or substance P into the ST 36 and were evaluated for up to 24 hours. Mechanical threshold was evaluated and the L4-L6 dorsal root ganglion (DRG) was used for analysis of the transient receptor potential vanilloid type 1 (TRPV1) overexpression. The mice from both the CFA or CCI models and treated with MA had significant increases in the thresholds for more than 24 hours. OUT stimulation did not change the thresholds. In the mice injected with each of the mediators, the thresholds were significantly increased for all times in both the CFA and CCI models. TRPV1 overexpression in CFA and CCI mice was reduced at all times by injection of serotonin, acetylcholine or substance P but not by injection of glutamate, histamine or bradykinin. Our data suggests that the neuroactive mediators released by acupuncture-induced tissue injury may contribute to acupuncture-induced analgesia. Copyright © 2018. Published by Elsevier B.V.

Impaired SIRT1 promotes the migration of vascular smooth muscle cell-derived foam cells.

PubMed

Zhang, Ming-Jie; Zhou, Yi; Chen, Lei; Wang, Xu; Pi, Yan; Long, Chun-Yan; Sun, Meng-Jiao; Chen, Xue; Gao, Chang-Yue; Li, Jing-Cheng; Zhang, Li-Li

2016-07-01

The formation of fat-laden foam cells, contributing to the fatty streaks of the plaques of atheroma, is the critical early process in atherosclerosis. The previous study demonstrated that vascular smooth muscle cells (VSMCs) contain a much larger burden of the excess cholesterol in comparison with monocyte-derived macrophages in human coronary atherosclerosis, as the main origin of foam cells. It is noteworthy that VSMC-derived foam cells are deposited in subintima but not media, where VSMCs normally deposit in. Therefore, migration from media to intima is an indispensable step for a VSMC to accrue neutral lipids and form foam cell. Whether this migration occurs paralleled with or prior to the formation of foam cell is still unclear. Herein, the present study was designed to test the VSMC migratory capability in the process of foam cell formation induced by oxidized low-density lipoprotein (oxLDL). In conclusion, we provide evidence that oxLDL induces the VSMC-derived foam cells formation with increased migration ability and MMP-9 expression, which were partly attributed to the impaired SIRT1 and enhanced nuclear factor-kappa B (NF-κB) activity. As activation of transient receptor potential vanilloid type 1 (TRPV1) has been reported to have anti-atherosclerotic effects, we investigated its role in oxLDL-treated VSMC migration. It is found that activating TRPV1 by capsaicin inhibits VSMC foam cell formation and the accompanied migration through rescuing the SIRT1 and suppressing NF-κB signaling. The present study provides evidence that SIRT1 may be a promising intervention target of atherosclerosis, and raises the prospect of TRPV1 in prevention and treatment of atherosclerosis.

Desalted deep-sea water improves cognitive function in mice by increasing the production of insulin-like growth factor-I in the hippocampus.

PubMed

Harada, Naoaki; Zhao, Juan; Kurihara, Hiroki; Nakagata, Naomi; Okajima, Kenji

2011-08-01

The stimulation of sensory neurons in the gastrointestinal (GI) tract improves cognitive function by increasing the hippocampal production of insulin-like growth factor-I (IGF-I) in mice. In the current study, we examined whether oral administration of desalted deep-sea water (DSW) increases the hippocampal production of IGF-I by stimulating sensory neurons in the GI tract, thereby improving cognitive function in mice. Desalted DSW increased calcitonin gene-related peptide (CGRP) release from dorsal root ganglion (DRG) neurons isolated from wild-type (WT) mice by activating transient receptor potential vanilloid 1. The plasma levels of IGF-I and tissue levels of CGRP, IGF-I, and IGF-I mRNA in the hippocampus were increased by oral administration of desalted DSW in WT mice. In these animals, nociceptive information originating from the GI tract was transmitted to the hippocampus via the spinothalamic pathway. Improvement of spatial learning was observed in WT mice after administration of desalted DSW. Distilled DSW showed results similar to those of desalted DSW in vitro and in vivo. None of the effects of desalted DSW in WT mice were observed after the administration of desalted DSW in CGRP-knockout (CGRP-/-) mice. No volatile compounds were detected in distilled DSW on GC-MS analysis. These observations suggest that desalted DSW may increase the hippocampal IGF-I production via sensory neuron stimulation in the Gl tract, thereby improving cognitive function in mice. Such effects of desalted DSW might not be dependent on the minerals but are dependent on the function of the water molecule itself. Copyright © 2011 Mosby, Inc. All rights reserved.

Klotho Prevents Renal Calcium Loss

PubMed Central

Alexander, R. Todd; Woudenberg-Vrenken, Titia E.; Buurman, Jan; Dijkman, Henry; van der Eerden, Bram C. J.; van Leeuwen, Johannes P.T.M.; Bindels, René J.

2009-01-01

Disturbed calcium (Ca2+) homeostasis, which is implicit to the aging phenotype of klotho-deficient mice, has been attributed to altered vitamin D metabolism, but alternative possibilities exist. We hypothesized that failed tubular Ca2+ absorption is primary, which causes increased urinary Ca2+ excretion, leading to elevated 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and its sequelae. Here, we assessed intestinal Ca2+ absorption, bone densitometry, renal Ca2+ excretion, and renal morphology via energy-dispersive x-ray microanalysis in wild-type and klotho−/− mice. We observed elevated serum Ca2+ and fractional excretion of Ca2+ (FECa) in klotho−/− mice. Klotho−/− mice also showed intestinal Ca2+ hyperabsorption, osteopenia, and renal precipitation of calcium-phosphate. Duodenal mRNA levels of transient receptor potential vanilloid 6 (TRPV6) and calbindin-D9K increased. In the kidney, klotho−/− mice exhibited increased expression of TRPV5 and decreased expression of the sodium/calcium exchanger (NCX1) and calbindin-D28K, implying a failure to absorb Ca2+ through the distal convoluted tubule/connecting tubule (DCT/CNT) via TRPV5. Gene and protein expression of the vitamin D receptor (VDR), 25-hydroxyvitamin D-1-α-hydroxylase (1αOHase), and calbindin-D9K excluded renal vitamin D resistance. By modulating the diet, we showed that the renal Ca2+ wasting was not secondary to hypercalcemia and/or hypervitaminosis D. In summary, these findings illustrate a primary defect in tubular Ca2+ handling that contributes to the precipitation of calcium-phosphate in DCT/CNT. This highlights the importance of klotho to the prevention of renal Ca2+ loss, secondary hypervitaminosis D, osteopenia, and nephrocalcinosis. PMID:19713312

TRPV1 receptors on unmyelinated C-fibres mediate colitis-induced sensitization of pelvic afferent nerve fibres in rats

PubMed Central

De Schepper, H U; De Winter, B Y; Van Nassauw, L; Timmermans, J-P; Herman, A G; Pelckmans, P A; De Man, J G

2008-01-01

Patients with inflammatory bowel disease often suffer from gastrointestinal motility and sensitivity disorders. The aim of the current study was to investigate the role of transient receptor potential of the vanilloid type 1 (TRPV1) receptors in the pathophysiology of colitis-induced pelvic afferent nerve sensitization. Trinitrobenzene sulphate (TNBS) colitis (7.5 mg, 30% ethanol) was induced in Wistar rats 72 h prior to the experiment. Single-fibre recordings were made from pelvic nerve afferents in the decentralized S1 dorsal root. Fibres responding to colorectal distension (CRD) were identified in controls and rats with TNBS colitis. The effect of the TRPV1 antagonist N-(4-tertiarybutylphenyl)-4-(3-chlorophyridin-2-yl)tetrahydropyrazine-1(2H)carboxamide (BCTC; 0.25–5 mg kg−1) or its vehicle (hydroxypropyl-β-cyclodextrin) was tested on the afferent response to repetitive distensions (60 mmHg). Immunocytochemical staining of TRPV1 and NF200, a marker for A-fibre neurons, was performed in the dorsal root ganglia L6–S1. TNBS colitis significantly increased the response to colorectal distension of pelvic afferent C-fibres. BCTC did not significantly affect the C-fibre response in controls, but normalized the sensitized response in rats with colitis. TNBS colitis increased the spontaneous activity of C-fibres, an effect which was insensitive to administration of BCTC. TNBS colitis had no effect on Aδ-fibres, nor was their activity modulated by BCTC. TNBS colitis caused an immunocytochemical up-regulation of TRPV1 receptors in the cell bodies of pelvic afferent NF200 negative neurons. TRPV1 signalling mediates the colitis-induced sensitization of pelvic afferent C-fibres to CRD, while Aδ-fibres are neither sensitized by colitis nor affected by TRPV1 inhibition. PMID:18755744

Thiazide-sensitive Na+ -Cl- cotransporter (NCC) gene inactivation results in increased duodenal Ca2+ absorption, enhanced osteoblast differentiation and elevated bone mineral density.

PubMed

Hsu, Yu-Juei; Yang, Sung-Sen; Cheng, Chih-Jen; Liu, Shu-Ting; Huang, Shih-Ming; Chau, Tom; Chu, Pauling; Salter, Donald M; Lee, Herng-Sheng; Lin, Shih-Hua

2015-01-01

Inactivation of the thiazide-sensitive sodium chloride cotransporter (NCC) due to genetic mutations in Gitelman's syndrome (GS) or pharmacological inhibition with thiazide diuretics causes hypocalciuria and increased bone mineral density (BMD) with unclear extrarenal calcium (Ca(2+) ) regulation. We investigated intestinal Ca(2+) absorption and bone Ca(2+) metabolism in nonsense Ncc Ser707X (S707X) homozygous knockin mice (Ncc(S707X/S707X) mice). Compared to wild-type and heterozygous knockin littermates, Ncc(S707X/S707X) mice had increased intestinal absorption of (45) Ca(2+) and expression of the active Ca(2+) transport machinery (transient receptor potential vanilloid 6, calbindin-D9K , and plasma membrane Ca(2+) ATPase isoform 1b). Ncc(S707X/S707X) mice had also significantly increased Ca(2+) content accompanied by greater mineral apposition rate (MAR) in their femurs and higher trabecular bone volume, cortical bone thickness, and BMD determined by μCT. Their osteoblast differentiation markers, such as bone alkaline phosphatase, procollagen I, osteocalcin, and osterix, were also significantly increased while osteoclast activity was unaffected. Analysis of marrow-derived bone cells, either treated with thiazide or directly cultured from Ncc S707X knockin mice, showed that the differentiation of osteoblasts was associated with increased phosphorylation of mechanical stress-induced focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In conclusion, NCC inhibition stimulates duodenal Ca(2+) absorption as well as osteoblast differentiation and bone Ca(2+) storage, possibly through a FAK/ERK dependent mechanism. © 2014 American Society for Bone and Mineral Research.

Incensole acetate, an incense component, elicits psychoactivity by activating TRPV3 channels in the brain

PubMed Central

Moussaieff, Arieh; Rimmerman, Neta; Bregman, Tatiana; Straiker, Alex; Felder, Christian C.; Shoham, Shai; Kashman, Yoel; Huang, Susan M.; Lee, Hyosang; Shohami, Esther; Mackie, Ken; Caterina, Michael J.; Walker, J. Michael; Fride, Ester; Mechoulam, Raphael

2008-01-01

Burning of Boswellia resin as incense has been part of religious and cultural ceremonies for millennia and is believed to contribute to the spiritual exaltation associated with such events. Transient receptor potential vanilloid (TRPV) 3 is an ion channel implicated in the perception of warmth in the skin. TRPV3 mRNA has also been found in neurons throughout the brain; however, the role of TRPV3 channels there remains unknown. Here we show that incensole acetate (IA), a Boswellia resin constituent, is a potent TRPV3 agonist that causes anxiolytic-like and antidepressive-like behavioral effects in wild-type (WT) mice with concomitant changes in c-Fos activation in the brain. These behavioral effects were not noted in TRPV3−/− mice, suggesting that they are mediated via TRPV3 channels. IA activated TRPV3 channels stably expressed in HEK293 cells and in keratinocytes from TRPV3+/+ mice. It had no effect on keratinocytes from TRPV3−/− mice and showed modest or no effect on TRPV1, TRPV2, and TRPV4, as well as on 24 other receptors, ion channels, and transport proteins. Our results imply that TRPV3 channels in the brain may play a role in emotional regulation. Furthermore, the biochemical and pharmacological effects of IA may provide a biological basis for deeply rooted cultural and religious traditions.—Moussaieff, A., Rimmerman, N., Bregman, T., Straiker, A., Felder, C. C., Shoham, S., Kashman, Y., Huang, S. M., Lee, H., Shohami, E., Mackie, K., Caterina, M. J., Walker, J. M., Fride, E., Mechoulam, R. Incensole acetate, an incense component, elicits psychoactivity by activating TRPV3 channels in the brain. PMID:18492727

Knockout of TRPV1 Exacerbates Left Ventricular Diastolic Dysfunction Induced by A High-fat Diet in Mice.

PubMed

Zhong, Beihua; Rubinstein, Jack; Ma, Shuangtao; Wang, Donna H

2018-05-03

Transient receptor potential vanilloid 1 (TRPV1) channels in sensory nerves have anti-oxidative properties and counteract obesity and diabetes that are associated with diastolic dysfunction with preserved ejection fraction. We tested the hypothesis that TRPV1 knockout exacerbates high-fat diet (HFD)-induced glucose intolerance and diastolic dysfunction. Trpv1-/- and wild-type (WT) mice were fed chow diet or HFD for 20 weeks. Then, we performed the intraperitoneal glucose tolerance test, measured the heart function through transthoracic echocardiography and Langendorff heart perfusion system, analyzed cardiac histology, and measured the myocardial superoxide production and the expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. HFD increased body weight, heart weight, and levels of fasting glucose, insulin, and leptin in both strains, with no differences between two strains. HFD impaired glucose tolerance in both strains with a more profound effect in Trpv1-/- than WT mice. HFD increased left ventricular (LV) internal diameter in diastole in both strains, while increased LV posterior wall thickness in diastole in Trpv1-/- but not in WT mice. HFD increased LV end-diastolic pressure in both strains with a further increase in Trpv1-/- mice, while decreased -dP/dt in Trpv1-/- but not in WT mice. HFD-induced cardiac collagen deposition and superoxide production were enhanced in Trpv1-/- mice. HFD upregulated cardiac p22phox in both strains, while increased p47phox in Trpv1-/- but not in WT mice. In summary, TRPV1 knockout exacerbates HFD-induced glucose intolerance, cardiac oxidative stress and collagen deposition, leading to aggravated LV diastolic dysfunction. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of polygodial and its direct derivatives on the mammalian Na+/K+-ATPase activity.

PubMed

Garcia, Diogo Gomes; Gonçalves-de-Albuquerque, Cassiano Felippe; da Silva, Camila Ignácio; Kiss, Robert; Dasari, Ramesh; Chandra, Sunena; Kornienko, Alexander; Burth, Patricia

2018-07-15

The sesquiterpene polygodial is an agonist of the transient receptor potential vanilloid 1 (TRPV1). Our group recently reported the synthesis and anticancer effects of polygodial and its derivatives, and showed that these compounds retain activity against apoptosis- and multidrug-resistant cancer cells. Herein, we tested the inhibitory effect of these compounds on the activity of the enzyme Na + /K + -ATPase (NKA) from kidney (α 1 isoform) and brain (α 2 and α 3 isoforms) guinea pig extracts. Polygodial (1) displayed a dose-dependent inhibition of both kidney and brain purified NKA preparations, with higher sensitivity for the cerebral isoforms. Polygo-11,12-diol (2) and C11,C12-pyridazine derivative (3) proved to be poor inhibitors. Unsaturated ester (4) and 9-epipolygodial (5) inhibited NKA preparations from brain and kidney, with the same inhibitory potency. Nevertheless, they did not achieve maximum inhibition even at higher concentration. Comparing the inhibitory potency in crude homogenates and purified preparations of NKA, compounds 4 and 5 revealed a degree of selectivity toward the renal enzyme. Kinetic studies showed a non-competitive inhibition for Na + and K + by compounds 1, 4 and 5 and for ATP by 1 and 4. However, compound 5 presented a competitive inhibition type. Furthermore, K + -activated p-nitrophenylphosphatase activity of these purified preparations was not inhibited by 1, 4 and 5, suggesting that these compounds acted in the initial phase of the enzyme's catalytic cycle. These findings suggest that the antitumor action of polygodial and its analogues may be linked to their NKA inhibitory properties and reinforce that NKA may be an important target for cancer therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Cardiac-specific knockout of ETA receptor mitigates low ambient temperature-induced cardiac hypertrophy and contractile dysfunction

PubMed Central

Zhang, Yingmei; Li, Linlin; Hua, Yinan; Nunn, Jennifer M.; Dong, Feng; Yanagisawa, Masashi; Ren, Jun

2012-01-01

Cold exposure is associated with oxidative stress and cardiac dysfunction. The endothelin (ET) system, which plays a key role in myocardial homeostasis, may participate in cold exposure-induced cardiovascular dysfunction. This study was designed to examine the role of ET-1 in cold stress-induced cardiac geometric and contractile responses. Wild-type (WT) and ETA receptor knockout (ETAKO) mice were assigned to normal or cold exposure (4°C) environment for 2 and 5 weeks prior to evaluation of cardiac geometry, contractile, and intracellular Ca2+ properties. Levels of the temperature sensor transient receptor potential vanilloid (TRPV1), mitochondrial proteins for biogenesis and oxidative phosphorylation, including UCP2, HSP90, and PGC1α were evaluated. Cold stress triggered cardiac hypertrophy, depressed myocardial contractile capacity, including fractional shortening, peak shortening, and maximal velocity of shortening/relengthening, reduced intracellular Ca2+ release, prolonged intracellular Ca2+ decay and relengthening duration, generation of ROS and superoxide, as well as apoptosis, the effects of which were blunted by ETAKO. Western blotting revealed downregulated TRPV1 and PGC1α as well as upregulated UCP2 and activation of GSK3β, GATA4, and CREB in cold-stressed WT mouse hearts, which were obliterated by ETAKO. Levels of HSP90, an essential regulator for thermotolerance, were unchanged. The TRPV1 agonist SA13353 attenuated whereas TRPV1 antagonist capsazepine mimicked cold stress- or ET-1-induced cardiac anomalies. The GSK3β inhibitor SB216763 ablated cold stress-induced cardiac contractile (but not remodeling) changes and ET-1-induced TRPV1 downregulation. These data suggest that ETAKO protects against cold exposure-induced cardiac remodeling and dysfunction mediated through TRPV1 and mitochondrial function. PMID:22442497

The dual blocker of FAAH/TRPV1 N-arachidonoylserotonin reverses the behavioral despair induced by stress in rats and modulates the HPA-axis.

PubMed

Navarria, Andrea; Tamburella, Alessandra; Iannotti, Fabio A; Micale, Vincenzo; Camillieri, Giovanni; Gozzo, Lucia; Verde, Roberta; Imperatore, Roberta; Leggio, Gian Marco; Drago, Filippo; Di Marzo, Vincenzo

2014-09-01

In recent years, several studies have explored the involvement of the deregulation of the hypothalamus-pituitary-adrenal (HPA) axis in the pathophysiology of stress-related disorders. HPA hyper-activation as a consequence of acute/chronic stress has been found to play a major role in the neurobiological changes that are responsible for the onset of such states. Currently available medications for depression, one of the most relevant stress-related disorders, present several limitations, including a time lag for treatment response and low rates of efficacy. N-Arachidonoylserotonin (AA-5-HT), a dual blocker at fatty acid amide hydrolase (FAAH, the enzyme responsible for the inactivation of the endocannabinoid anandamide) and transient receptor potential vanilloid type-1 channel (TRPV1), produces anxiolytic-like effects in mice. The present study was designed to assess the capability of AA-5-HT to reverse the behavioral despair following exposure to stress in rats and the role of the HPA-axis. Behavioral tasks were performed, and corticosterone and endocannabinoid (anandamide and 2-arachidonoylglycerol) levels were measured in selected brain areas critically involved in the pathophysiology of stress-related disorders (medial PFC and hippocampus) under basal and stress conditions, and in response to treatment with AA-5-HT. Our data show that AA-5-HT reverses the rat behavioral despair in the forced swim test under stress conditions, and this effect is associated with the normalization of the HPA-axis deregulation that follows stress application and only in part with elevation of anandamide levels. Blockade of FAAH and TRPV1 may thus represent a novel target to design novel therapeutic strategies for the treatment of stress-related disorders. Copyright © 2014 Elsevier Ltd. All rights reserved.

Trigeminal Ganglion Neurons of Mice Show Intracellular Chloride Accumulation and Chloride-Dependent Amplification of Capsaicin-Induced Responses

PubMed Central

Schöbel, Nicole; Radtke, Debbie; Lübbert, Matthias; Gisselmann, Günter; Lehmann, Ramona; Cichy, Annika; Schreiner, Benjamin S. P.; Altmüller, Janine; Spector, Alan C.; Spehr, Jennifer; Hatt, Hanns; Wetzel, Christian H.

2012-01-01

Intracellular Cl− concentrations ([Cl−]i) of sensory neurons regulate signal transmission and signal amplification. In dorsal root ganglion (DRG) and olfactory sensory neurons (OSNs), Cl− is accumulated by the Na+-K+-2Cl− cotransporter 1 (NKCC1), resulting in a [Cl−]i above electrochemical equilibrium and a depolarizing Cl− efflux upon Cl− channel opening. Here, we investigate the [Cl−]i and function of Cl− in primary sensory neurons of trigeminal ganglia (TG) of wild type (WT) and NKCC1−/− mice using pharmacological and imaging approaches, patch-clamping, as well as behavioral testing. The [Cl−]i of WT TG neurons indicated active NKCC1-dependent Cl− accumulation. Gamma-aminobutyric acid (GABA)A receptor activation induced a reduction of [Cl−]i as well as Ca2+ transients in a corresponding fraction of TG neurons. Ca2+ transients were sensitive to inhibition of NKCC1 and voltage-gated Ca2+ channels (VGCCs). Ca2+ responses induced by capsaicin, a prototypical stimulus of transient receptor potential vanilloid subfamily member-1 (TRPV1) were diminished in NKCC1−/− TG neurons, but elevated under conditions of a lowered [Cl−]o suggesting a Cl−-dependent amplification of capsaicin-induced responses. Using next generation sequencing (NGS), we found expression of different Ca2+-activated Cl− channels (CaCCs) in TGs of mice. Pharmacological inhibition of CaCCs reduced the amplitude of capsaicin-induced responses of TG neurons in Ca2+ imaging and electrophysiological recordings. In a behavioral paradigm, NKCC1−/− mice showed less avoidance of the aversive stimulus capsaicin. In summary, our results strongly argue for a Ca2+-activated Cl−-dependent signal amplification mechanism in TG neurons that requires intracellular Cl− accumulation by NKCC1 and the activation of CaCCs. PMID:23144843

Dystrophic cardiomyopathy: role of TRPV2 channels in stretch-induced cell damage.

PubMed

Lorin, Charlotte; Vögeli, Isabelle; Niggli, Ernst

2015-04-01

Duchenne muscular dystrophy (DMD), a degenerative pathology of skeletal muscle, also induces cardiac failure and arrhythmias due to a mutation leading to the lack of the protein dystrophin. In cardiac cells, the subsarcolemmal localization of dystrophin is thought to protect the membrane from mechanical stress. The absence of dystrophin results in an elevated stress-induced Ca2+ influx due to the inadequate functioning of several proteins, such as stretch-activated channels (SACs). Our aim was to investigate whether transient receptor potential vanilloid channels type 2 (TRPV2) form subunits of the dysregulated SACs in cardiac dystrophy. We defined the role of TRPV2 channels in the abnormal Ca2+ influx of cardiomyocytes isolated from dystrophic mdx mice, an established animal model for DMD. In dystrophic cells, western blotting showed that TRPV2 was two-fold overexpressed. While normally localized intracellularly, in myocytes from mdx mice TRPV2 channels were translocated to the sarcolemma and were prominent along the T-tubules, as indicated by immunocytochemistry. Membrane localization was confirmed by biotinylation assays. Furthermore, in mdx myocytes pharmacological modulators suggested an abnormal activity of TRPV2, which has a unique pharmacological profile among TRP channels. Confocal imaging showed that these compounds protected the cells from stress-induced abnormal Ca2+ signals. The involvement of TRPV2 in these signals was confirmed by specific pore-blocking antibodies and by small-interfering RNA ablation of TRPV2. Together, these results establish the involvement of TRPV2 in a stretch-activated calcium influx pathway in dystrophic cardiomyopathy, contributing to the defective cellular Ca2+ handling in this disease. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Compounds from Sichuan and Melegueta peppers activate, covalently and non-covalently, TRPA1 and TRPV1 channels

PubMed Central

Riera, CE; Menozzi-Smarrito, C; Affolter, M; Michlig, S; Munari, C; Robert, F; Vogel, H; Simon, SA; le Coutre, J

2009-01-01

Background and purpose: Oily extracts of Sichuan and Melegueta peppers evoke pungent sensations mediated by different alkylamides [mainly hydroxy-α-sanshool (α-SOH)] and hydroxyarylalkanones (6-shogaol and 6-paradol). We assessed how transient receptor potential ankyrin 1 (TRPA1) and TRP vanilloid 1 (TRPV1), two chemosensory ion channels, participate in these pungent sensations. Experimental approach: The structure–activity relationships of these molecules on TRPA1 and TRPV1 was measured by testing natural and synthetic analogues using calcium and voltage imaging on dissociated dorsal root ganglia neurons and human embryonic kidney 293 cells expressing the wild-type channels or specific cysteine mutants using glutathione trapping as a model to probe TRPA1 activation. In addition, using Trpv1 knockout mice, the compounds' aversive responses were measured in a taste brief-access test. Key results: For TRPA1 activation, the cis C6 double bond in the polyenic chain of α-SOH was critical, whereas no structural specificity was required for activation of TRPV1. Both 6-shogaol and 6-paradol were found to activate TRPV1 and TRPA1 channels, whereas linalool, an abundant terpene in Sichuan pepper, activated TRPA1 but not TRPV1 channels. Alkylamides and 6-shogaol act on TRPA1 by covalent bonding whereas none of these compounds activated TRPV1 through such interactions. Finally, TRPV1 mutant mice retained sensitivity to 6-shogaol but were not responsive to α-SOH. Conclusions and implications: The pungent nature of components of Sichuan and Melegueta peppers was mediated via interactions with TRPA1 and TRPV1 channels and may explain the aversive properties of these compounds. PMID:19594761

Nerve growth factor release from the urothelium increases via activation of bladder C-fiber in rats with cerebral infarction.

PubMed

Yokokawa, Ryusei; Akino, Hironobu; Ito, Hideaki; Zha, Xinmin; Yokoyama, Osamu

2017-08-01

There are some reports that bladder C-fibers are partially involved in detrusor overactivity in patients with brain lesions. We investigated the contribution of bladder C-fiber to decreased bladder capacity in rats with cerebral infarction. Cerebral infarction was induced under halothane anesthesia by left middle cerebral artery occlusion with 4-0 nylon thread in female Sprague-Dawley rats. Intramural amounts of ATP and prostaglandin E 2 , in vivo and in vitro ATP, NGF, and prostaglandin E 2 release from the distended bladder urothelium, and changes in mRNA expressions of sensor molecules and receptors were monitored 6 h after the occlusion. Cystometry was performed in rats with or without resiniferatoxin pretreatment. Overexpression of sensor molecule, transient receptor potential vanilloid-type channel 1, acid-sensing ion channel 2, purinergic receptors P2X 3 , and M 2 /M 3 muscarinic receptors was found in the bladder. These changes were accompanied by increases in ATP and NGF release from the urothelium. In contrast, when bladder C-fibers were desensitized by resiniferatoxin, no increase in NGF release from the urothelium was found either in vivo or in vitro. There was no difference in the percentage decrease in bladder capacity between cerebral infarction rats pretreated with resiniferatoxin and cerebral infarction rats without pretreatment. Results indicate that expression of sensor molecules in the bladder is altered by distant infarction in the brain. ATP and NGF release from the urothelium also increased. NGF release was related to activation of bladder C-fibers. Bladder C-fibers might not contribute much to decreased bladder capacity caused by cerebral infarction. © 2016 Wiley Periodicals, Inc.

TRPV1 channels and the progesterone receptor Sig-1R interact to regulate pain.

PubMed

Ortíz-Rentería, Miguel; Juárez-Contreras, Rebeca; González-Ramírez, Ricardo; Islas, León D; Sierra-Ramírez, Félix; Llorente, Itzel; Simon, Sidney A; Hiriart, Marcia; Rosenbaum, Tamara; Morales-Lázaro, Sara L

2018-02-13

The Transient Receptor Potential Vanilloid 1 (TRPV1) ion channel is expressed in nociceptors where, when activated by chemical or thermal stimuli, it functions as an important transducer of painful and itch-related stimuli. Although the interaction of TRPV1 with proteins that regulate its function has been previously explored, their modulation by chaperones has not been elucidated, as is the case for other mammalian TRP channels. Here we show that TRPV1 physically interacts with the Sigma 1 Receptor (Sig-1R), a chaperone that binds progesterone, an antagonist of Sig-1R and an important neurosteroid associated to the modulation of pain. Antagonism of Sig-1R by progesterone results in the down-regulation of TRPV1 expression in the plasma membrane of sensory neurons and, consequently, a decrease in capsaicin-induced nociceptive responses. This is observed both in males treated with a synthetic antagonist of Sig-1R and in pregnant females where progesterone levels are elevated. This constitutes a previously undescribed mechanism by which TRPV1-dependent nociception and pain can be regulated.

Trpv4 Mediates Hypotonic Inhibition of Central Osmosensory Neurons via Taurine Gliotransmission.

PubMed

Ciura, Sorana; Prager-Khoutorsky, Masha; Thirouin, Zahra S; Wyrosdic, Joshua C; Olson, James E; Liedtke, Wolfgang; Bourque, Charles W

2018-05-22

The maintenance of hydromineral homeostasis requires bidirectional detection of changes in extracellular fluid osmolality by primary osmosensory neurons (ONs) in the organum vasculosum laminae terminalis (OVLT). Hypertonicity excites ONs in part through the mechanical activation of a variant transient receptor potential vanilloid-1 channel (dn-Trpv1). However, the mechanism by which local hypotonicity inhibits ONs in the OVLT remains unknown. Here, we show that hypotonicity can reduce the basal activity of dn-Trpv1 channels and hyperpolarize acutely isolated ONs. Surprisingly, we found that mice lacking dn-Trpv1 maintain normal inhibitory responses to hypotonicity when tested in situ. In the intact setting, hypotonicity inhibits ONs through a non-cell-autonomous mechanism that involves glial release of the glycine receptor agonist taurine through hypotonicity activated anion channels (HAAC) that are activated subsequent to Ca 2+ influx through Trpv4 channels. Our study clarifies how Trpv4 channels contribute to the inhibition of OVLT ONs during hypotonicity in situ. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

TRPV1 Antagonists and Chronic Pain: Beyond Thermal Perception

PubMed Central

Brandt, Michael R.; Beyer, Chad E.; Stahl, Stephen M.

2012-01-01

In the last decade, considerable evidence as accumulated to support the development of Transient Receptor Potential Vanilloid 1 (TRPV1) antagonists for the treatment of various chronic pain conditions. Whereas there is a widely accepted rationale for the development of TRPV1 antagonists for the treatment of various inflammatory pain conditions, their development for indications of chronic pain, where conditions of tactical, mechanical and spontaneous pain predominate, is less clear. Preclinical localization and expression studies provide a firm foundation for the use of molecules targeting TRPV1 for conditions of bone pain, osteoarthritis and neuropathic pain. Selective TRPV1 antagonists weakly attenuate tactile and mechanical hypersensivity and are partially effective for behavioral and electrophysiological endpoints that incorporate aspects of spontaneous pain. While initial studies with TRPV1 antagonist in normal human subjects indicate a loss of warm thermal perception, clinical studies assessing allelic variants suggests that TRPV1 may mediate other sensory modalities under certain conditions. The focus of this review is to summarize the current perspectives of TRPV1 for the treatment of conditions beyond those with a primary thermal sensitivity. PMID:24288084

Fine thermotactic discrimination between the optimal and slightly cooler temperatures via a TRPV channel in chordotonal neurons.

PubMed

Kwon, Young; Shen, Wei L; Shim, Hye-Seok; Montell, Craig

2010-08-04

Animals select their optimal environmental temperature, even when faced with alternatives that differ only slightly. This behavior is critical as small differences in temperature of only several degrees can have a profound effect on the survival and rate of development of poikilothermic animals, such as the fruit fly. Here, we demonstrate that Drosophila larvae choose their preferred temperature of 17.5 degrees C over slightly cooler temperatures (14-16 degrees C) through activation of chordotonal neurons. Mutations affecting a transient receptor potential (TRP) vanilloid channel, Inactive (Iav), which is expressed specifically in chordotonal neurons, eliminated the ability to choose 17.5 degrees C over 14-16 degrees C. The impairment in selecting 17.5 degrees C resulted from absence of an avoidance response, which is normally mediated by an increase in turns at the lower temperatures. We conclude that the decision to select the preferred over slightly cooler temperatures requires iav and is achieved by activating chordotonal neurons, which in turn induces repulsive behaviors, due to an increase in high angle turns.

Fine Thermotactic Discrimination between the Optimal and Slightly Cooler Temperatures via a TRPV Channel in Chordotonal Neurons

PubMed Central

Kwon, Young; Shen, Wei L.; Shim, Hye-Seok; Montell, Craig

2012-01-01

Animals select their optimal environmental temperature, even when faced with alternatives that differ only slightly. This behavior is critical as small differences in temperature of only several degrees can have a profound effect on the survival and rate of development of poikilothermic animals, such as the fruit fly. Here, we demonstrate that Drosophila larvae choose their preferred temperature of 17.5°C over slightly cooler temperatures (14–16°C) through activation of chordotonal neurons. Mutations affecting a transient receptor potential (TRP) vanilloid channel, Inactive (Iav), which is expressed specifically in chordotonal neurons, eliminated the ability to choose 17.5°C over 14–16°C. The impairment in selecting 17.5°C resulted from absence of an avoidance response, which is normally mediated by an increase in turns at the lower temperatures. We conclude that the decision to select the preferred over slightly cooler temperatures requires iav and is achieved by activating chordotonal neurons, which in turn induces repulsive behaviors, due to an increase in high angle turns. PMID:20685989

TRPV5-mediated Ca2+ Reabsorption and Hypercalciuria

NASA Astrophysics Data System (ADS)

Renkema, Kirsten Y.; Hoenderop, Joost G. J.; Bindels, René J. M.

2007-04-01

The concerted action of the intestine, kidney and bone results in the maintenance of a normal Ca2+ balance, a mechanism that is tightly controlled by the calciotropic hormones vitamin D, parathyroid hormone and calcitonin. Disturbances in the Ca2+ balance have been linked to diverse pathophysiological disorders like urolithiasis, hypertension, electroencephalogram abnormalities and rickets. Importantly, the final amount of Ca2+ that is released from the body is determined in the distal part of the nephron, where active Ca2+ reabsorption occurs. Here, Transient Receptor Potential Vanilloid member 5 (TRPV5), a highly Ca2+-selective channel, has been recognized as the gatekeeper of active Ca2+ reabsorption. The in vivo relevance of TRPV5 has been further investigated by the characterization of TRPV5 knockout (TRPV5-/-) mice, which exhibit severe disturbances in renal Ca2+ handling, such as profound hypercalciuria, intestinal Ca2+ hyperabsorption and reduced bone thickness. Hypercalciuria increases the risk of kidney stone formation in these mice. This review highlights our current knowledge about TRPV5-mediated Ca2+ reabsorption and emphasizes the physiological relevance and the clinical implications related to the TRPV5-/- mice model.

Laryngeal and tracheal afferent nerve stimulation evokes swallowing in anaesthetized guinea pigs

PubMed Central

Tsujimura, Takanori; Udemgba, Chioma; Inoue, Makoto; Canning, Brendan J

2013-01-01

We describe swallowing reflexes evoked by laryngeal and tracheal vagal afferent nerve stimulation in anaesthetized guinea pigs. The swallowing reflexes evoked by laryngeal citric acid challenges were abolished by recurrent laryngeal nerve (RLN) transection and mimicked by electrical stimulation of the central cut ends of an RLN. By contrast, the number of swallows evoked by upper airway/pharyngeal distensions was not significantly reduced by RLN transection but they were virtually abolished by superior laryngeal nerve transection. Laryngeal citric acid-evoked swallowing was mimicked by laryngeal capsaicin challenges, implicating transient receptor potential vanilloid 1 (TRPV1)-expressing laryngeal afferent nerves arising from the jugular ganglia. The swallowing evoked by citric acid and capsaicin and evoked by electrical stimulation of either the tracheal or the laryngeal mucosa occurred at stimulation intensities that were typically subthreshold for evoking cough in these animals. Swallowing evoked by airway afferent nerve stimulation also desensitized at a much slower rate than cough. We speculate that swallowing is an essential component of airway protection from aspiration associated with laryngeal and tracheal afferent nerve activation. PMID:23858010

Thermal actuation in TRPV1: Role of embedded lipids and intracellular domains.

PubMed

Melnick, Corey; Kaviany, Massoud

2018-05-07

The transient response potential cation channel TRPV1 responds to high temperature, but many of the mechanisms driving its thermal actuation remain unclear. Its recently resolved structure has enabled a number of molecular dynamics (MD) studies focused on illuminating these mechanisms. We add to these efforts by performing the first all-atom MD simulations of its most recently resolved structure at different temperatures. While the complete, thermally induced transition of TRPV1 from its closed to open configuration remains elusive, our analysis of the hydrogen bonding networks, thermodynamics, hydration, and principal components of motion provide a wealth of information on the mechanisms which initiate or influence the thermal opening in TRPV1. In particular, we (i) support the previously proposed mechanism driving thermal actuation in the extracellular pore of TRPV1, (ii) present new hypotheses regarding the thermal actuation in the C-terminal and adjacent linker domains, and (iii) support and build upon the existing hypothesis regarding the role of the vanilloid binding pocket and lipids embedded therein. Copyright © 2018 Elsevier Ltd. All rights reserved.

Peripheral gabapentin regulates mosquito allergy-induced itch in mice.

PubMed

Akiyama, Tasuku; Andoh, Tsugunobu; Ohtsuka, Eiji; Nojima, Hiroshi; Ouchi, Hidekazu; Takahata, Hiroki; Kuraishi, Yasushi

2018-05-26

The antipruritic activity of gabapentin, an anticonvulsant, was studied in a mouse model of allergic itch. In mice sensitized by an extract of the salivary glands of the mosquito (ESGM), an intradermal injection of ESGM elicited scratching and increased peripheral nerve firing. Oral or intradermal administration of gabapentin at the ESGM injection site inhibited ESGM-induced scratching and peripheral nerve firing. However, gabapentin did not affect histamine-induced scratching. The distributions of immunoreactivity to the voltage-dependent calcium channel α 2 δ-1 subunit, a site of gabapentin action, and the histamine H 1 receptor differed in the mouse dorsal root ganglia. The α 2 δ-1 subunit was mainly found in neurons that were 15-20 µm in diameter, whereas the H 1 receptor was mainly in 20-30 µm neurons. In addition, α 2 δ-1 subunit immunoreactivity co-localized with that of transient receptor potential vanilloid 1 (TRPV1). These results suggest that gabapentin regulates allergic itch by acting on the calcium channel α 2 δ-1 subunit in peripheral TRPV1-positive neurons. Copyright © 2018 Elsevier B.V. All rights reserved.

Searching for proprioceptors in human facial muscles.

PubMed

Cobo, Juan L; Abbate, Francesco; de Vicente, Juan C; Cobo, Juan; Vega, José A

2017-02-15

The human craniofacial muscles innervated by the facial nerve typically lack muscle spindles. However these muscles have proprioception that participates in the coordination of facial movements. A functional substitution of facial proprioceptors by cutaneous mechanoreceptors has been proposed but at present this alternative has not been demonstrated. Here we have investigated whether other kinds of sensory structures are present in two human facial muscles (zygomatic major and buccal). Human checks were removed from Spanish cadavers, and processed for immunohistochemical detection of nerve fibers (neurofilament proteins and S100 protein) and two putative mechanoproteins (acid-sensing ion channel 2 and transient receptor potential vanilloid 4) associated with mechanosensing. Nerves of different calibers were found in the connective septa and within the muscle itself. In all the muscles analysed, capsular corpuscle-like structures resembling elongated or round Ruffini-like corpuscles were observed. Moreover the axon profiles within these structures displayed immunoreactivity for both putative mechanoproteins. The present results demonstrate the presence of sensory structures in facial muscles that can substitute for typical muscle spindles as the source of facial proprioception. Copyright © 2017 Elsevier B.V. All rights reserved.

ΔN-TRPV1: A Molecular Co-detector of Body Temperature and Osmotic Stress.

PubMed

Zaelzer, Cristian; Hua, Pierce; Prager-Khoutorsky, Masha; Ciura, Sorana; Voisin, Daniel L; Liedtke, Wolfgang; Bourque, Charles W

2015-10-06

Thirst and antidiuretic hormone secretion occur during hyperthermia or hypertonicity to preserve body hydration. These vital responses are triggered when hypothalamic osmoregulatory neurons become depolarized by ion channels encoded by an unknown product of the transient receptor potential vanilloid-1 gene (Trpv1). Here, we show that rodent osmoregulatory neurons express a transcript of Trpv1 that mediates the selective translation of a TRPV1 variant that lacks a significant portion of the channel's amino terminus (ΔN-TRPV1). The mRNA transcript encoding this variant (Trpv1dn) is widely expressed in the brains of osmoregulating vertebrates, including the human hypothalamus. Transfection of Trpv1dn into heterologous cells induced the expression of ion channels that could be activated by either hypertonicity or by heating in the physiological range. Moreover, expression of Trpv1dn rescued the osmosensory and thermosensory responses of single hypothalamic neurons obtained from Trpv1 knockout mice. ΔN-TRPV1 is therefore a co-detector of core body temperature and fluid tonicity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Transient Receptor Potential Vanilloid 2 Regulates Myocardial Response to Exercise

PubMed Central

Naticchioni, Mindi; Karani, Rajiv; Smith, Margaret A.; Onusko, Evan; Robbins, Nathan; Jiang, Min; Radzyukevich, Tatiana; Fulford, Logan; Gao, Xu; Apel, Ryan; Heiny, Judith; Rubinstein, Jack; Koch, Sheryl E.

2015-01-01

The myocardial response to exercise is an adaptive mechanism that permits the heart to maintain cardiac output via improved cardiac function and development of hypertrophy. There are many overlapping mechanisms via which this occurs with calcium handling being a crucial component of this process. Our laboratory has previously found that the stretch sensitive TRPV2 channels are active regulators of calcium handling and cardiac function under baseline conditions based on our observations that TRPV2-KO mice have impaired cardiac function at baseline. The focus of this study was to determine the cardiac function of TRPV2-KO mice under exercise conditions. We measured skeletal muscle at baseline in WT and TRPV2-KO mice and subjected them to various exercise protocols and measured the cardiac response using echocardiography and molecular markers. Our results demonstrate that the TRPV2-KO mouse did not tolerate forced exercise although they became increasingly exercise tolerant with voluntary exercise. This occurs as the cardiac function deteriorates further with exercise. Thus, our conclusion is that TRPV2-KO mice have impaired cardiac functional response to exercise. PMID:26356305

The Mechanism of Action of Zingerone in the Pacemaker Potentials of Interstitial Cells of Cajal Isolated from Murine Small Intestine.

PubMed

Kim, Jung Nam; Kim, Hyun Jung; Kim, Iksung; Kim, Yun Tai; Kim, Byung Joo

2018-01-01

Zingerone, a major component found in ginger root, is clinically effective for the treatment of various diseases. Interstitial cells of Cajal (ICCs) are the pacemaker cells responsible for slow waves in the gastrointestinal (GI) tract. We investigated the effects of zingerone on the pacemaker potentials of ICCs to assess its mechanisms of action and its potential as a treatment for GI tract motility disorder. We isolated ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record the pacemaker potentials in cultured ICCs. Under the current clamping mode, zingerone inhibited pacemaker potentials of ICCs concentration-dependently. These effects were blocked not by capsazepine, a transient receptor potential vanilloid 1 (TRPV1) channel blocker, but by glibenclamide, a specific ATP-sensitive K+ channel blocker. Pretreatment with SQ-22536 (an adenylate cyclase inhibitor), LY294002 (a phosphoinositide 3-kinase inhibitor), and calphostin C (a protein kinase C (PKC) inhibitor) did not block the effects of zingerone on the pacemaker potentials relative to treatment with zingerone alone. However, zingerone-induced pacemaker potential inhibition was blocked by 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ; a guanylate cyclase inhibitor), KT5823 (a protein kinase G (PKG) inhibitor), and L-NAME (a non-selective nitric oxide synthase (NOS) inhibitor). In addition, zingerone stimulated cyclic guanosine monophosphate (cGMP) production in ICCs. Finally, pretreatment with PD98059 (a p42/44 mitogen-activated protein kinase (MAPK) inhibitor), SB203580 (a p38 MAPK inhibitor), and SP600125 (c-Jun N-terminal kinases (JNK)-specific inhibitor) blocked the zingerone-induced pacemaker potential inhibition. These results suggest that zingerone concentration-dependently inhibits pacemaker potentials of ICCs via NO/cGMP-dependent ATP-sensitive K+ channels through MAPK-dependent pathways. Taken together, this study shows that zingerone may have the potential for development as a GI regulation agent. © 2018 The Author(s). Published by S. Karger AG, Basel.

Inward rectifier potassium (Kir2.1) channels as end-stage boosters of endothelium-dependent vasodilators.

PubMed

Sonkusare, Swapnil K; Dalsgaard, Thomas; Bonev, Adrian D; Nelson, Mark T

2016-06-15

Increase in endothelial cell (EC) calcium activates calcium-sensitive intermediate and small conductance potassium (IK and SK) channels, thereby causing hyperpolarization and endothelium-dependent vasodilatation. Endothelial cells express inward rectifier potassium (Kir) channels, but their role in endothelium-dependent vasodilatation is not clear. In the mesenteric arteries, only ECs, but not smooth muscle cells, displayed Kir currents that were predominantly mediated by the Kir2.1 isoform. Endothelium-dependent vasodilatations in response to muscarinic receptor, TRPV4 (transient receptor potential vanilloid 4) channel and IK/SK channel agonists were highly attenuated by Kir channel inhibitors and by Kir2.1 channel knockdown. These results point to EC Kir channels as amplifiers of vasodilatation in response to increases in EC calcium and IK/SK channel activation and suggest that EC Kir channels could be targeted to treat endothelial dysfunction, which is a hallmark of vascular disorders. Endothelium-dependent vasodilators, such as acetylcholine, increase intracellular Ca(2+) through activation of transient receptor potential vanilloid 4 (TRPV4) channels in the plasma membrane and inositol trisphosphate receptors in the endoplasmic reticulum, leading to stimulation of Ca(2+) -sensitive intermediate and small conductance K(+) (IK and SK, respectively) channels. Although strong inward rectifier K(+) (Kir) channels have been reported in the native endothelial cells (ECs) their role in EC-dependent vasodilatation is not clear. Here, we test the idea that Kir channels boost the EC-dependent vasodilatation of resistance-sized arteries. We show that ECs, but not smooth muscle cells, of small mesenteric arteries have Kir currents, which are substantially reduced in EC-specific Kir2.1 knockdown (EC-Kir2.1(-/-) ) mice. Elevation of extracellular K(+) to 14 mm caused vasodilatation of pressurized arteries, which was prevented by endothelial denudation and Kir channel inhibitors (Ba(2+) , ML-133) or in the arteries from EC-Kir2.1(-/-) mice. Potassium-induced dilatations were unaffected by inhibitors of TRPV4, IK and SK channels. The Kir channel blocker, Ba(2+) , did not affect currents through TRPV4, IK or SK channels. Endothelial cell-dependent vasodilatations in response to activation of muscarinic receptors, TRPV4 channels or IK/SK channels were reduced, but not eliminated, by Kir channel inhibitors or EC-Kir2.1(-/-) . In angiotensin II-induced hypertension, the Kir channel function was not altered, although the endothelium-dependent vasodilatation was severely impaired. Our results support the concept that EC Kir2 channels boost vasodilatory signals that are generated by Ca(2+) -dependent activation of IK and SK channels. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Inward rectifier potassium (Kir2.1) channels as end‐stage boosters of endothelium‐dependent vasodilators

PubMed Central

Dalsgaard, Thomas; Bonev, Adrian D.; Nelson, Mark T.

2016-01-01

Key points Increase in endothelial cell (EC) calcium activates calcium‐sensitive intermediate and small conductance potassium (IK and SK) channels, thereby causing hyperpolarization and endothelium‐dependent vasodilatation.Endothelial cells express inward rectifier potassium (Kir) channels, but their role in endothelium‐dependent vasodilatation is not clear.In the mesenteric arteries, only ECs, but not smooth muscle cells, displayed Kir currents that were predominantly mediated by the Kir2.1 isoform.Endothelium‐dependent vasodilatations in response to muscarinic receptor, TRPV4 (transient receptor potential vanilloid 4) channel and IK/SK channel agonists were highly attenuated by Kir channel inhibitors and by Kir2.1 channel knockdown.These results point to EC Kir channels as amplifiers of vasodilatation in response to increases in EC calcium and IK/SK channel activation and suggest that EC Kir channels could be targeted to treat endothelial dysfunction, which is a hallmark of vascular disorders. Abstract Endothelium‐dependent vasodilators, such as acetylcholine, increase intracellular Ca2+ through activation of transient receptor potential vanilloid 4 (TRPV4) channels in the plasma membrane and inositol trisphosphate receptors in the endoplasmic reticulum, leading to stimulation of Ca2+‐sensitive intermediate and small conductance K+ (IK and SK, respectively) channels. Although strong inward rectifier K+ (Kir) channels have been reported in the native endothelial cells (ECs) their role in EC‐dependent vasodilatation is not clear. Here, we test the idea that Kir channels boost the EC‐dependent vasodilatation of resistance‐sized arteries. We show that ECs, but not smooth muscle cells, of small mesenteric arteries have Kir currents, which are substantially reduced in EC‐specific Kir2.1 knockdown (EC‐Kir2.1 −/−) mice. Elevation of extracellular K+ to 14 mm caused vasodilatation of pressurized arteries, which was prevented by endothelial denudation and Kir channel inhibitors (Ba2+, ML‐133) or in the arteries from EC‐Kir2.1 −/− mice. Potassium‐induced dilatations were unaffected by inhibitors of TRPV4, IK and SK channels. The Kir channel blocker, Ba2+, did not affect currents through TRPV4, IK or SK channels. Endothelial cell‐dependent vasodilatations in response to activation of muscarinic receptors, TRPV4 channels or IK/SK channels were reduced, but not eliminated, by Kir channel inhibitors or EC‐Kir2.1 −/−. In angiotensin II‐induced hypertension, the Kir channel function was not altered, although the endothelium‐dependent vasodilatation was severely impaired. Our results support the concept that EC Kir2 channels boost vasodilatory signals that are generated by Ca2+‐dependent activation of IK and SK channels. PMID:26840527

RAGE-dependent potentiation of TRPV1 currents in sensory neurons exposed to high glucose.

PubMed

Lam, Doris; Momeni, Zeinab; Theaker, Michael; Jagadeeshan, Santosh; Yamamoto, Yasuhiko; Ianowski, Juan P; Campanucci, Verónica A

2018-01-01

Diabetes mellitus is associated with sensory abnormalities, including exacerbated responses to painful (hyperalgesia) or non-painful (allodynia) stimuli. These abnormalities are symptoms of diabetic peripheral neuropathy (DPN), which is the most common complication that affects approximately 50% of diabetic patients. Yet, the underlying mechanisms linking hyperglycemia and symptoms of DPN remain poorly understood. The transient receptor potential vanilloid 1 (TRPV1) channel plays a central role in such sensory abnormalities and shows elevated expression levels in animal models of diabetes. Here, we investigated the function of TRPV1 channels in sensory neurons cultured from the dorsal root ganglion (DRG) of neonatal mice, under control (5mM) and high glucose (25mM) conditions. After maintaining DRG neurons in high glucose for 1 week, we observed a significant increase in capsaicin (CAP)-evoked currents and CAP-evoked depolarizations, independent of TRPV1 channel expression. These functional changes were largely dependent on the expression of the receptor for Advanced Glycation End-products (RAGE), calcium influx, cytoplasmic ROS accumulation, PKC, and Src kinase activity. Like cultured neurons from neonates, mature neurons from adult mice also displayed a similar potentiation of CAP-evoked currents in the high glucose condition. Taken together, our data demonstrate that under the diabetic condition, DRG neurons are directly affected by elevated levels of glucose, independent of vascular or glial signals, and dependent on RAGE expression. These early cellular and molecular changes to sensory neurons in vitro are potential mechanisms that might contribute to sensory abnormalities that can occur in the very early stages of diabetes.

RAGE-dependent potentiation of TRPV1 currents in sensory neurons exposed to high glucose

PubMed Central

Lam, Doris; Momeni, Zeinab; Theaker, Michael; Jagadeeshan, Santosh; Yamamoto, Yasuhiko; Ianowski, Juan P.

2018-01-01

Diabetes mellitus is associated with sensory abnormalities, including exacerbated responses to painful (hyperalgesia) or non-painful (allodynia) stimuli. These abnormalities are symptoms of diabetic peripheral neuropathy (DPN), which is the most common complication that affects approximately 50% of diabetic patients. Yet, the underlying mechanisms linking hyperglycemia and symptoms of DPN remain poorly understood. The transient receptor potential vanilloid 1 (TRPV1) channel plays a central role in such sensory abnormalities and shows elevated expression levels in animal models of diabetes. Here, we investigated the function of TRPV1 channels in sensory neurons cultured from the dorsal root ganglion (DRG) of neonatal mice, under control (5mM) and high glucose (25mM) conditions. After maintaining DRG neurons in high glucose for 1 week, we observed a significant increase in capsaicin (CAP)-evoked currents and CAP-evoked depolarizations, independent of TRPV1 channel expression. These functional changes were largely dependent on the expression of the receptor for Advanced Glycation End-products (RAGE), calcium influx, cytoplasmic ROS accumulation, PKC, and Src kinase activity. Like cultured neurons from neonates, mature neurons from adult mice also displayed a similar potentiation of CAP-evoked currents in the high glucose condition. Taken together, our data demonstrate that under the diabetic condition, DRG neurons are directly affected by elevated levels of glucose, independent of vascular or glial signals, and dependent on RAGE expression. These early cellular and molecular changes to sensory neurons in vitro are potential mechanisms that might contribute to sensory abnormalities that can occur in the very early stages of diabetes. PMID:29474476

Isothiocyanates from Wasabia japonica activate transient receptor potential ankyrin 1 channel.

PubMed

Uchida, Kunitoshi; Miura, Yosuke; Nagai, Masashi; Tominaga, Makoto

2012-11-01

6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC) and 6-(methylthio)hexyl isothiocyanate (6-MTITC) have low pungency and are responsible for the fresh flavor of wasabi (Wasabia japonica [Miq] Matsumura). In this study, we found that these two isothiocyanates activate transient receptor potential ankyrin 1 (TRPA1), and 6-MSITC activates transient receptor potential vanilloid 1 (TRPV1), but not other transient receptor potential channels expressed in sensory neurons. Both 6-MSITC and 6-MTITCinduced intracellular Ca(2+) increases in human embryonic kidney-derived 293 cells expressing mouse TRPA1 (mTRPA1) as measured by Ca(2+) imaging. In whole-cell patch-clamp recordings, 6-MSITC and 6-MTITC dose-dependently activated both mTRPA1 (EC(50) = 147±26 µM for 6-MSITC and 30±3 µM for 6-MTITC) and human TRPA1 (hTRPA1; EC(50) = 39±4 µM for 6-MSITC and 34±3 µM for 6-MTITC). In addition, TRPA1 N-terminal cysteines, which are reported to be important for channel activation by electrophilic ligands, were involved in 6-MSITC- and 6-MTITC-evoked TRPA1 activation. These isothiocyanates also activated endogenous TRPA1 expressed in mouse dorsal root ganglion neurons and intraplantar injection of 10-30 mM 6-MSITC-evoked pain-related behaviors in mice. These results indicate the following: 1) 6-MSITC and 6-MTITC activate both mTRPA1 and hTRPA1; 2) 6-MSITC activates mTRPV1; and 3) the pharmacological functions of these isothiocyanates could be derived from TRPA1 activation.

Role of Transient Receptor Potential Ion Channels and Evoked Levels of Neuropeptides in a Formaldehyde-Induced Model of Asthma in Balb/c Mice

PubMed Central

Wu, Yang; You, Huihui; Ma, Ping; Li, Li; Yuan, Ye; Li, Jinquan; Ye, Xin; Liu, Xudong; Yao, Hanchao; Chen, Ruchong; Lai, Kefang; Yang, Xu

2013-01-01

Objective Asthma is a complex pulmonary inflammatory disease characterized by the hyper-responsiveness, remodeling and inflammation of airways. Formaldehyde is a common indoor air pollutant that can cause asthma in people experiencing long-term exposure. The irritant effect and adjuvant effect are the two possible pathways of formaldehyde promoted asthma. Methodology/Principal Findings To explore the neural mechanisms and adjuvant effect of formaldehyde, 48 Balb/c mice in six experimental groups were exposed to (a) vehicle control; (b) ovalbumin; (c) formaldehyde (3.0 mg/m3); (d) ovalbumin+formaldehyde (3.0 mg/m3); (e) ovalbumin+formaldehyde (3.0 mg/m3)+HC-030031 (transient receptor potential ankyrin 1 antagonist); (f) ovalbumin+formaldehyde (3.0 mg/m3)+ capsazepine (transient receptor potential vanilloid 1 antagonist). Experiments were conducted after 4 weeks of combined exposure and 1-week challenge with aerosolized ovalbumin. Airway hyper-responsiveness, pulmonary tissue damage, eosinophil infiltration, and increased levels of interleukin-4, interleukin-6, interleukin-1β, immunoglobulin E, substance P and calcitonin gene-related peptide in lung tissues were found in the ovalbumin+formaldehyde (3.0 mg/m3) group compared with the values seen in ovalbumin -only immunized mice. Except for interleukin-1β levels, other changes in the levels of biomarker could be inhibited by HC-030031 and capsazepine. Conclusions/Significance Formaldehyde might be a key risk factor for the rise in asthma cases. Transient receptor potential ion channels and neuropeptides have important roles in formaldehyde promoted-asthma. PMID:23671638

Derivatives of furanditerpenes from Pterodon genus: Pharmacological studies disclose their potential as chronic pain relief in mice.

PubMed

Spindola, Humberto M; Grando, Rogério; Figueiredo, Mariana C; Basting, Rosana; Queiroz, N C A; de Fátima, Ângelo; de Carvalho, João E; Wang, Zaijie J; Foglio, M A

2017-06-05

Pterodon genus fruits are commercially available at the Brazilian medicinal market used in folk medicine due to their anti-inflammatory, analgesic, and anti-rheumatic effects. Previous studies demonstrated that furanditerpenes possessing vouacapan skeleton, isolated from Pterodon genus, possess expressive antinociceptive activities, with promising moiety for the development of new analgesic products. The antinociceptive properties of compounds 6α,7β-6α-hidroxivouacapan-7β-17β-lactone (HVL) and 6α-oxovouacapan-7β-17β-lactone (OVL), semi-synthetic analogues of furanditerpenes previously reported as analgesic agents were evaluated on animal experimental models (Spindola et al., 2010, 2011). The chemical-induced pain methods used in the present work, demonstrated for the first time that both compounds HVL and OVL have potential as important templates for the development of chronic pain control drugs. The main findings of this work were that both compounds were: effective in the writhing test; reduced paw edema in the carrageenan test; effective in the inflammatory phase of the formalin test corroborating their activity against inflammatory pain conditions; effective on reducing pain through the stimulation of vanilloid receptors sensible to capsaicin (an important pathway for chronic pain maintenance); reduced the pain stimulus caused by PGE 2 injection (a pathway involved in chronic pain hypersensitivity); effective on decreasing mechanical allodynia in the CFA-model, demonstrating their potential use against chronic pain disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

The molecular basis of urgency: regional difference of vanilloid receptor expression in the human urinary bladder.

PubMed

Liu, Lu; Mansfield, Kylie J; Kristiana, Ika; Vaux, Kenneth J; Millard, Richard J; Burcher, Elizabeth

2007-01-01

Treatments targeting vanilloid receptor TRPV1 are effective in some bladder disorders. Our aim was to determine the expression profiles of TRPV1 in regions of human bladder and test the hypothesis that there would be an upregulation of TRPV1 in mucosa of patients with bladder hypersensitivity but not idiopathic detrusor overactivity (IDO). Women with sensory urgency (SU), interstitial cystitis (IC), and IDO were investigated by videourodynamics and cystoscopy. Control biopsies were used for comparison. Biopsies were dissected into mucosa and muscle, and evaluated for TRPV1 mRNA expression using quantitative competitive RT-PCR (QC-RT-PCR). TRPV1 mRNA from SU trigonal mucosa was significantly higher than control trigonal mucosa or SU bladder body mucosa. In contrast, in IDO patients, there was no difference between trigonal mucosa and body mucosa. In IC biopsies, RNA quality was substandard and unable to be used for analysis. The most striking finding was that TRPV1 mRNA expressed in SU trigonal mucosa was significantly inversely correlated with the bladder volume at first sensation of filling during cystometry. No such relationship was seen for IDO trigonal mucosa. No difference was seen in bladder body mucosa from any disease groups compared with age-matched control. The symptoms of SU were associated with the increased expression of TRPV1 mRNA in the trigonal mucosa. No upregulation or regional differences of TRPV1 mRNA were seen in IDO patients. TRPV1 may play a role in SU and premature first bladder sensation on filling.

A “burning” therapy for burning mouth syndrome: preliminary results with the administration of topical capsaicin.

PubMed

Azzi, L; Croveri, F; Pasina, L; Porrini, M; Vinci, R; Manfredini, M; Tettamanti, L; Tagliabue, A; Silvestre-Rangil, J; Spadari, F

2017-01-01

Burning mouth syndrome is defined as an intraoral burning sensation for which no medical or dental cause can be found. Recently, researchers have demonstrated an altered trophism of the small nerve fibres and alterations in the numbers of TRPV-1 vanilloid receptors. Capsaicin is a molecule that is contained in hot peppers and is specifically detected by TRPV-1 vanilloid receptors that are distributed in the oral mucosae. We aimed at verifying if topical capsaicin could prove to be an effective treatment of Burning Mouth Syndrome. A group of 99 BMS patients were recruited. We subdivided the BMS patients into two groups: the collaborative patients, who expressed a predominantly neuropathic pattern of symptoms, and the non-collaborative patients, who were characterised by stronger psychogenic patterns of the syndrome. Both groups underwent topical therapy with capsaicin in the form of a mouth rinse 3 times a day for a long period. After 1 year of treatment, the final overall success rate was approximately 78%, but with a significant difference in the success rates of the two groups of patients (87% and 20% among the collaborative and non-collaborative patients, respectively; p=0.000). The use of topical capsaicin can improve the oral discomfort of BMS patients, especially during the first month of therapy, but it is more effective for those patients in which the neuropathic component of the syndrome is predominant. Our hypothesis is that chronic stimulation with capsaicin leads to decreases in burning symptoms. This phenomenon is called desensitisation and is accompanied by substantial improvements in oral symptoms.

Transient Receptor Potential Channels as Targets for Phytochemicals

PubMed Central

2015-01-01

To date, 28 mammalian transient receptor potential (TRP) channels have been cloned and characterized. They are grouped into six subfamilies on the basis of their amino acid sequence homology: TRP Ankyrin (TRPA), TRP Canonical (TRPC), TRP Melastatin (TRPM), TRP Mucolipin (TRPML), TRP Polycystin (TRPP), and TRP Vanilloid (TRPV). Most of the TRP channels are nonselective cation channels expressed on the cell membrane and exhibit variable permeability ratios for Ca2+ versus Na+. They mediate sensory functions (such as vision, nociception, taste transduction, temperature sensation, and pheromone signaling) and homeostatic functions (such as divalent cation flux, hormone release, and osmoregulation). Significant progress has been made in our understanding of the specific roles of these TRP channels and their activation mechanisms. In this Review, the emphasis will be on the activation of TRP channels by phytochemicals that are claimed to exert health benefits. Recent findings complement the anecdotal evidence that some of these phytochemicals have specific receptors and the activation of which is responsible for the physiological effects. Now, the targets for these phytochemicals are being unveiled; a specific hypothesis can be proposed and tested experimentally to infer a scientific validity of the claims of the health benefits. The broader and pressing issues that have to be addressed are related to the quantities of the active ingredients in a given preparation, their bioavailability, metabolism, adverse effects, excretion, and systemic versus local effects. PMID:24926802

TRPV1 Channels Are Functionally Coupled with BK(mSlo1) Channels in Rat Dorsal Root Ganglion (DRG) Neurons

PubMed Central

Yan, Zonghe; Kong, Wenjuan; Liu, Beiying; Li, Xia; Yao, Jing; Zhang, Yuexuan; Qin, Feng; Ding, Jiuping

2013-01-01

The transient receptor potential vanilloid receptor 1 (TRPV1) channel is a nonselective cation channel activated by a variety of exogenous and endogenous physical and chemical stimuli, such as temperature (≥42 °C), capsaicin, a pungent compound in hot chili peppers, and allyl isothiocyanate. Large-conductance calcium- and voltage-activated potassium (BK) channels regulate the electric activities and neurotransmitter releases in excitable cells, responding to changes in membrane potentials and elevation of cytosolic calcium ions (Ca2+). However, it is unknown whether the TRPV1 channels are coupled with the BK channels. Using patch-clamp recording combined with an infrared laser device, we found that BK channels could be activated at 0 mV by a Ca2+ influx through TRPV1 channels not the intracellular calcium stores in submilliseconds. The local calcium concentration around BK is estimated over 10 μM. The crosstalk could be affected by 10 mM BAPTA, whereas 5 mM EGTA was ineffectual. Fluorescence and co-immunoprecipitation experiments also showed that BK and TRPV1 were able to form a TRPV1-BK complex. Furthermore, we demonstrated that the TRPV1-BK coupling also occurs in dosal root ganglion (DRG) cells, which plays a critical physiological role in regulating the “pain” signal transduction pathway in the peripheral nervous system. PMID:24147119

Binding of Capsaicin to the TRPV1 Ion Channel.

PubMed

Darré, Leonardo; Domene, Carmen

2015-12-07

Transient receptor potential (TRP) ion channels constitute a notable family of cation channels involved in the ability of an organisms to detect noxious mechanical, thermal, and chemical stimuli that give rise to the perception of pain, taste, and changes in temperature. One of the most experimentally studied agonist of TRP channels is capsaicin, which is responsible for the burning sensation produced when chili pepper is in contact with organic tissues. Thus, understanding how this molecule interacts and regulates TRP channels is essential to high impact pharmacological applications, particularly those related to pain treatment. The recent publication of a three-dimensional structure of the vanilloid receptor 1 (TRPV1) in the absence and presence of capsaicin from single particle electron cryomicroscopy experiments provides the opportunity to explore these questions at the atomic level. In the present work, molecular docking and unbiased and biased molecular dynamics simulations were employed to generate a structural model of the capsaicin-channel complex. In addition, the standard free energy of binding was estimated using alchemical transformations coupled with conformational, translational, and orientational restraints on the ligand. Key binding modes consistent with previous experimental data are identified, and subtle but essential dynamical features of the binding site are characterized. These observations shed some light into how TRPV1 interacts with capsaicin, and may help to refine design parameters for new TRPV1 antagonists, and potentially guide further developments of TRP channel modulators.

Fish oil concentrate delays sensitivity to thermal nociception in mice

PubMed Central

Veigas, Jyothi M.; Williams, Paul J.; Halade, Ganesh; Rahman, Mizanur M.; Yoneda, Toshiyuki; Fernandes, Gabriel

2011-01-01

Fish oil has been used to alleviate pain associated with inflammatory conditions such as rheumatoid arthritis. The anti-inflammatory property of fish oil is attributed to the n-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid. Contrarily, vegetable oils such as safflower oil are rich in n-6 fatty acids which are considered to be mediators of inflammation. This study investigates the effect of n-3 and n-6 fatty acids rich oils as dietary supplements on the thermally induced pain sensitivity in healthy mice. C57Bl/6J mice were fed diet containing regular fish oil, concentrated fish oil formulation (CFO) and safflower oil (SO) for 6 months. Pain sensitivity was measured by plantar test and was correlated to the expression of acid sensing ion channels (ASICs), transient receptor potential vanilloid 1 (TRPV1) and c-fos in dorsal root ganglion cells. Significant delay in sensitivity to thermal nociception was observed in mice fed CFO compared to mice fed SO (p<0.05). A significant diminution in expression of ion channels such as ASIC1a (64%), ASIC13 (37%) and TRPV1 (56%) coupled with reduced expression of c-fos, a marker of neuronal activation, was observed in the dorsal root ganglion cells of mice fed CFO compared to that fed SO. In conclusion, we describe here the potential of fish oil supplement in reducing sensitivity to thermal nociception in normal mice. PMID:21345372

Phosphoinositide regulation of TRPV1 revisited

PubMed Central

Rohacs, Tibor

2015-01-01

The heat- and capsaicin-sensitive Transient Receptor Potential Vanilloid 1 ion channel (TRPV1) is regulated by plasma membrane phosphoinositides. The effects of these lipids on this channel have been controversial. Recent articles re-ignited the debate and also offered resolution to place some of the data in a coherent picture. This review summarizes the literature on this topic and provides a detailed and critical discussion on the experimental evidence for the various effects of phosphatidylinositol 4,5-bisphosphayte [PI(4,5)P2 or PIP2] on TRPV1. We conclude that PI(4,5)P2 and potentially its precursor PI(4)P are positive cofactors for TRPV1, acting via direct interaction with the channel, and their depletion by Ca2+-induced activation of phospholipase Cδ isoforms (PLCδ) limits channel activity during capsaicin-induced desensitization. Other negatively charged lipids at higher concentrations can also support channel activity, which may explain some controversies in the literature. PI(4,5)P2 also partially inhibits channel activity in some experimental settings, and relief from this inhibition upon PLCβ activation may contribute to sensitization. The negative effect of PI(4,5)P2 is more controversial and its mechanism is less well understood. Other TRP channels from the TRPV and TRPC families may also undergo similar dual regulation by phosphoinositides, thus the complexity of TRPV1 regulation is not unique to this channel. PMID:25754030

Towards Development of a Dermal Pain Model: In Vitro Activation of Rat and Human Transient Receptor Potential Ankyrin Repeat 1 and Safe Dermal Injection of o-Chlorobenzylidene Malononitrile to Rat.

PubMed

Annas, Anita; Berg, Anna-Lena; Nyman, Eva; Meijer, Thomas; Lundgren, Viveka; Franzén, Bo; Ståhle, Lars

2015-12-01

During clinical development of analgesics, it is important to have access to pharmacologically specific human pain models. o-Chlorobenzylidene malononitrile (CS) is a selective and potent agonist of the transient receptor potential ankyrin repeat 1 (TRPA1), which is a transducer molecule in nociceptors sensing reactive chemical species. While CS has been subject to extensive toxicological investigations in animals and human beings, its effects on intradermal or subcutaneous injection have not previously been reported. We have investigated the potential of CS to be used as an agonist on TRPA1 in human experimental pain studies. A calcium influx assay was used to confirm the capacity of CS to activate TRPA1 with >100,000 times the selectivity over the transient receptor potential vanilloid receptor 1. CS dose-dependently (EC50 0.9 μM) released calcitonin gene-related peptide in rat dorsal root ganglion cultures, supporting involvement in pain signalling. In a local tolerance study, injection of a single intradermal dose of 20 mM CS to rats resulted in superficial, circular crusts at the injection sites after approximately 4 days. The histopathology evaluation revealed a mild, acute inflammatory reaction in the epidermis and dermis at the intradermal CS injection site 1 day after administration. After 14 days, the epidermal epithelium was fully restored. The symptoms were not considered to be adverse, and it is suggested that doses up to 20 μL of 20 mM CS can be safely administered to human beings. In conclusion, our data support development of a CS human dermal pain model. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Mechanosensitive Ca²⁺-permeable channels in human leukemic cells: pharmacological and molecular evidence for TRPV2.

PubMed

Pottosin, Igor; Delgado-Enciso, Iván; Bonales-Alatorre, Edgar; Nieto-Pescador, María G; Moreno-Galindo, Eloy G; Dobrovinskaya, Oxana

2015-01-01

Mechanosensitive channels are present in almost every living cell, yet the evidence for their functional presence in T lymphocytes is absent. In this study, by means of the patch-clamp technique in attached and inside-out modes, we have characterized cationic channels, rapidly activated by membrane stretch in Jurkat T lymphoblasts. The half-activation was achieved at a negative pressure of ~50mm Hg. In attached mode, single channel currents displayed an inward rectification and the unitary conductance of ~40 pS at zero command voltage. In excised inside-out patches the rectification was transformed to an outward one. Mechanosensitive channels weakly discriminated between mono- and divalent cations (PCa/PNa~1) and were equally permeable for Ca²⁺ and Mg²⁺. Pharmacological analysis showed that the mechanosensitive channels were potently blocked by amiloride (1mM) and Gd³⁺ (10 μM) in a voltage-dependent manner. They were also almost completely blocked by ruthenium red (1 μM) and SKF 96365 (250 μM), inhibitors of transient receptor potential vanilloid 2 (TRPV2) channels. At the same time, the channels were insensitive to 2-aminoethoxydiphenyl borate (2-APB, 100 μM) or N-(p-amylcinnamoyl)anthranilic acid (ACA, 50 μM), antagonists of transient receptor potential canonical (TRPC) or transient receptor potential melastatin (TRPM) channels, respectively. Human TRPV2 siRNA virtually abolished the stretch-activated current. TRPV2 are channels with multifaceted functions and regulatory mechanisms, with potentially important roles in the lymphocyte Ca²⁺ signaling. Implications of their regulation by mechanical stress are discussed in the context of lymphoid cells functions. Copyright © 2014 Elsevier B.V. All rights reserved.

N-Arachidonoyl Dopamine Modulates Acute Systemic Inflammation via Nonhematopoietic TRPV1

PubMed Central

Lawton, Samira K.; Xu, Fengyun; Tran, Alphonso; Wong, Erika; Schumacher, Mark; Wilhelmsen, Kevin

2017-01-01

N-Arachidonoyl dopamine (NADA) is an endogenous lipid that potently activates the transient receptor potential vanilloid 1 (TRPV1), which mediates pain and thermosensation. NADA is also an agonist of cannabinoid receptors 1 and 2. We have reported that NADA reduces the activation of cultured human endothelial cells by LPS and TNF-α. Thus far, in vivo studies using NADA have focused on its neurologic and behavioral roles. In this article, we show that NADA potently decreases in vivo systemic inflammatory responses and levels of the coagulation intermediary plasminogen activator inhibitor 1 in three mouse models of inflammation: LPS, bacterial lipopeptide, and polymicrobial intra-abdominal sepsis. We also found that the administration of NADA increases survival in endotoxemic mice. Additionally, NADA reduces blood levels of the neuropeptide calcitonin gene-related peptide but increases the neuropeptide substance P in LPS-treated mice. We demonstrate that the anti-inflammatory effects of NADA are mediated by TRPV1 expressed by nonhematopoietic cells and provide data suggesting that neuronal TRPV1 may mediate NADA’s anti-inflammatory effects. These results indicate that NADA has novel TRPV1-dependent anti-inflammatory properties and suggest that the endovanilloid system might be targeted therapeutically in acute inflammation. PMID:28701511

Geraniol-a flavoring agent with multifunctional effects in protecting the gastric and duodenal mucosa.

PubMed

de Carvalho, Katharinne Ingrid Moraes; Bonamin, Flavia; Dos Santos, Raquel Cássia; Périco, Larissa Lucena; Beserra, Fernando Pereira; de Sousa, Damião Pergentino; Filho, José Maria Barbosa; da Rocha, Lucia Regina Machado; Hiruma-Lima, Clelia Akiko

2014-04-01

Geraniol is an acyclic monoterpene alcohol commonly used as a flavoring agent. The present study was undertaken to investigate antiulcerogenic effects of geraniol and to determine the possible mechanisms involved in this action. In the model of the ethanol-induced ulcer, treatment of rats with geraniol by oral route significantly inhibited gastric lesions by 70 % (7.50 mg/kg) to 99 % (200 mg/kg). Analysis of the gastric tissue of rats treated with geraniol (7.50 mg/kg) revealed that total glutathione content levels (GSH) increased and levels of myeloperoxidase (MPO) decreased in the gastric mucosa. Oral treatment with geraniol significantly decreased the number of ulcerative lesions induced by ischemia/reperfusion injury by 71 % and the duodenal ulcers induced by cysteamine by 68 %. The action of geraniol was mediated by the activation of defensive mucosa-protective factors such as the nitric oxide (NO) pathway, endogenous prostaglandins, increased mucus production, increased sulfhydryl compounds, antioxidant properties and the stimulation of calcitonin gene-related peptide (CGRP) release through the activation of transient receptor potential vanilloid (TRPV). The multifaceted gastroprotective mechanisms of geraniol represent a promising option for the treatment of gastric and duodenal mucosa injury.

Magnetogenetics: Remote Control of Cellular Signaling with Magnetic Fields

NASA Astrophysics Data System (ADS)

Sauer, Jeremy P.

Means for temporally regulating gene expression and cellular activity are invaluable for elucidating the underlying physiological processes and have therapeutic implications. Here we report the development of a system for remote regulation of gene expression by low frequency radiowaves (RF) or by a static magnetic field. We accomplished this by first adding iron oxide nanoparticles - either exogenously or as genetically encoded ferritin/ferric oxyhydroxide particle. These particles have been designed with affinity to the plasma membrane ion channel Transient Receptor Potential Vanilloid 1 (TRPV1) by a conjugated antibody. Application of a magnetic field stimulates the particle to gate the ion channel and this, in turn, initiates calcium-dependent transgene expression. We first demonstrated in vitro that TRPV1 can be actuated to cause calcium flux into the cell by directly applying a localized magnetic field. In mice expressing these genetically encoded components, application of external magnetic field caused remote stimulation of insulin transgene expression and significantly lowered blood glucose. In addition, we are investigating mechanisms by which iron oxide nanoparticles can absorb RF, and transduce this energy to cause channel opening. This robust, repeatable method for remote cellular regulation in vivo may ultimately have applications in basic science, as well as in technology and therapeutics.

Neurotrophins and Migraine.

PubMed

Martins, L B; Teixeira, A L; Domingues, R B

2017-01-01

Neurotrophins (NTs) have been implicated in generation and modulation of nociceptive pathways. Change in NTs levels is associated with painful conditions and neurological diseases such as migraine. Currently, it is generally recognized that migraine headaches result from the activation and sensitization of trigeminal sensory afferent fibers leading to neuropeptides release such as calcitonin gene-related peptide (CGRP) and substance P (SP). This triggers an inflammatory cascade causing a neurogenic inflammation. The agents responsible for trigeminal activation and release of neuropeptides are still unclear. It is known that the transient receptor potential vanilloid receptor-1 (TRPV1) is an important mediator of CGRP and SP release. TRPV1 is closely associated with tyrosine receptors kinases (Trk), which are NTs receptors. NTs can act on TRPV1 increasing its sensitivity to painful stimuli, therefore predisposing to hyperalgesia. Upregulation of ion channels and pain receptors in dorsal root ganglion neurons may be alternative mechanisms by which NTs contribute to pain development. Only a few studies have been performed to investigate the role of NTs in migraine. These studies have reported changes in NTs levels in migraine patients either during the migraine attack or in free-headache periods. © 2017 Elsevier Inc. All rights reserved.

Human Digital Meissner Corpuscles Display Immunoreactivity for the Multifunctional Ion Channels Trpc6 and Trpv4.

PubMed

Alonso-González, Paula; Cabo, Roberto; San José, Isabel; Gago, Angel; Suazo, Iván C; García-Suárez, Olivia; Cobo, Juan; Vega, José A

2017-06-01

Ion channels are at the basis of the sensory processes including mechanosensing. Some members of the transient receptor potential (TRP) ion channel superfamily have been proposed as mechanosensors, but their putative role in mechanotransduction is controversial. Among them there are TRP canonical 6 (TRPC6) and TRP vanilloid 4 (TRPV4) ion channels, which are known to cooperate in mechanical hyperalgesia. Here, we investigated the occurrence, distribution, and possible colocalization of TRPC6 and TRPV4 in human digital Meissner sensory corpuscles using immunohistochemistry and double immunofluorescence (associate with markers for specific corpuscular constituents). TRPC6 immunoreactivity was restricted to the axon of Meissner corpuscles, whereas TRPV4 was detected in the axon but also in the lamellar cells. Moreover, axonal colocalization of TRPV4 and TRPC6 was found in the digital Meissner corpuscles. Present results demonstrate for the first time the occurrence and colocalization of two ion channels candidates to mechanosensors in human cutaneous mechanoreceptors. The functional significance of these ion channels in that place remains to be clarified, but should be related to different properties of mechanosensitivity. Anat Rec, 300:1022-1031, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Ionotropic and metabotropic proton-sensing receptors involved in airway inflammation in allergic asthma.

PubMed

Aoki, Haruka; Mogi, Chihiro; Okajima, Fumikazu

2014-01-01

An acidic microenvironment has been shown to evoke a variety of airway responses, including cough, bronchoconstriction, airway hyperresponsiveness (AHR), infiltration of inflammatory cells in the lung, and stimulation of mucus hyperproduction. Except for the participation of transient receptor potential vanilloid-1 (TRPV1) and acid-sensing ion channels (ASICs) in severe acidic pH (of less than 6.0)-induced cough and bronchoconstriction through sensory neurons, the molecular mechanisms underlying extracellular acidic pH-induced actions in the airways have not been fully understood. Recent studies have revealed that ovarian cancer G protein-coupled receptor 1 (OGR1)-family G protein-coupled receptors, which sense pH of more than 6.0, are expressed in structural cells, such as airway smooth muscle cells and epithelial cells, and in inflammatory and immune cells, such as eosinophils and dendritic cells. They function in a variety of airway responses related to the pathophysiology of inflammatory diseases, including allergic asthma. In the present review, we discuss the roles of ionotropic TRPV1 and ASICs and metabotropic OGR1-family G protein-coupled receptors in the airway inflammation and AHR in asthma and respiratory diseases.

A molecular determinant of phosphoinositide affinity in mammalian TRPV channels

NASA Astrophysics Data System (ADS)

Velisetty, Phanindra; Borbiro, Istvan; Kasimova, Marina A.; Liu, Luyu; Badheka, Doreen; Carnevale, Vincenzo; Rohacs, Tibor

2016-06-01

Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is an important cofactor for ion channels. Affinity for this lipid is a major determinant of channel inhibition by depletion of PI(4,5)P2 upon phospholipase C (PLC) activation. Little is known about what determines PI(4,5)P2 affinity in mammalian ion channels. Here we report that two members of the Transient Receptor Potential Vanilloid (TRPV) ion channel family, TRPV5 and TRPV6 lack a positively charged residue in the TM4-TM5 loop that was shown to interact with PI(4,5)P2 in TRPV1, which shows high affinity for this lipid. When this positively charged residue was introduced to either TRPV6 or TRPV5, they displayed markedly higher affinities for PI(4,5)P2, and were largely resistant to inhibition by PI(4,5)P2 depletion. Furthermore, Ca2+-induced inactivation of TRPV6 was essentially eliminated in the G488R mutant, showing the importance of PLC-mediated PI(4,5)P2 depletion in this process. Computational modeling shows that the introduced positive charge interacts with PI(4,5)P2 in TRPV6.

TRPV1 agonist monoacylglycerol increases UCP1 content in brown adipose tissue and suppresses accumulation of visceral fat in mice fed a high-fat and high-sucrose diet.

PubMed

Iwasaki, Yusaku; Tamura, Yasuko; Inayoshi, Kimiko; Narukawa, Masataka; Kobata, Kenji; Chiba, Hiroshige; Muraki, Etsuko; Tsunoda, Nobuyo; Watanabe, Tatsuo

2011-01-01

The administration of such a transient receptor potential vanilloid 1 (TRPV1) agonist as capsaicin, which is a pungent ingredient of red pepper, promotes energy metabolism and suppresses visceral fat accumulation. We have recently identified monoacylglycerols (MGs) having an unsaturated long-chain fatty acid as the novel TRPV1 agonist in foods. We investigated in this present study the effects of dietary MGs on uncoupling protein 1 (UCP1) expression in interscapular brown adipose tissue (IBAT) and on fat accumulation in mice fed with a high-fat, high-sucrose diet. The MG30 diet that substituted 30% of all lipids for MGs (a mixture of 1-oleoylglycerol, 1-linoleoylglycerol and 1-linolenoylglycerol) significantly increased the UCP1 content of IBAT and decreased the weight of epididymal white adipose tissue, and the serum glucose, total cholesterol and free fatty acid levels. The diet containing only 1-oleoylglycerol as MG also increased UCP1 expression in IBAT. MGs that activated TRPV1 also therefore induced the expression of UCP 1 and prevented visceral fat accumulation as well as capsaicin.

Molecular Modeling of the Structural and Dynamical Changes in Calcium Channel TRPV5 Induced by the African-Specific A563T Variation.

PubMed

Wang, Lingyun; Holmes, Ross P; Peng, Ji-Bin

2016-03-01

Transient receptor potential cation channels, vanilloid subfamily, member 5 (TRPV5) plays a key role in active Ca(2+) reabsorption in the kidney. Variations in TRPV5 occur at high frequency in African populations and may contribute to their higher efficiency of Ca(2+) reabsorption. One of the African specific variations, A563T, exhibits increased Ca(2+) transport ability. However, it is unclear how this variation influences the channel pore. On the basis of the structure of TRPV1, a TRPV5 model was generated to simulate the structural and dynamical changes induced by the A563T variation. On the basis of this model, amino acid residue 563 interacts with V540, which is one residue away from the key residue, D542, involved in Ca(2+) selectivity and Mg(2+) blockade. The A563T variation increases secondary structure stability and reduces dynamical motion of D542. In addition, the A563T variation alters the electrostatic potential of the outer surface of the pore. Differences in contact between selective filter residues and residue 563 and in electrostatic potential between the two TRPV5 variants were also observed in another model derived from an alternative alignment in the selective filters between TRPV5 and TRPV1. These findings indicate that the A563T variation induces structural, dynamical, and electrostatic changes in the TRPV5 pore, providing structural insight into the functional alterations associated with the A563T variation.

Nefopam, a non-opioid analgesic, does not alleviate experimental work/effort dyspnoea in healthy humans: A randomised controlled trial.

PubMed

Dangers, Laurence; Laviolette, Louis; Charbit, Bény; Similowski, Thomas; Morélot-Panzini, Capucine

2016-08-01

Dyspnoea is a distressing and debilitating symptom with a major impact on quality of life. Alleviation of dyspnoea therefore constitutes a major clinical challenge. When causative physiological disorders cannot be corrected ("persistent dyspnoea"), nonspecific treatment must be considered. Morphine alleviates dyspnoea but has numerous side-effects including ventilatory depression, which justifies looking for alternatives. Certain forms of dyspnoea involve C-fibres, and can be attenuated by C-fibres blockade. We hypothesised that nefopam, a non-sedative benzoxazocine analgesic known to block the transient receptor potential vanilloid subtype 1 abundantly present on C-fibres, would attenuate dyspnoea. We conducted a randomised, double-blind, placebo-controlled crossover study of nefopam in healthy subjects submitted to experimental work/effort dyspnoea by inspiratory threshold loading (15 healthy male volunteers; age 23-41). We studied a perceptual outcome (dyspnoea visual analogue scale -D-VAS-) and a neurophysiological outcome (effect of nefopam on dyspnoea-pain counter-irritation as assessed by laser-evoked potentials; an effect of nefopam on dyspnoea was hypothetised to reduce the ability of dyspnoea to inhibit pain). Somaesthetic evoked potentials (SEPs) were studied as a control. A statistically significant decrease in LEP amplitude was observed in response to loading with nefopam (F = 19.1; p < 0.001) and placebo (F = 5.73 and p < 0.001), with no significant difference between nefopam and placebo and no change in SEP characteristics. In this study, nefopam did not exhibit any effects on dyspnoea. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel shogaol analog suppresses cancer cell invasion and inflammation, and displays cytoprotective effects through modulation of NF-κB and Nrf2-Keap1 signaling pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, Fei-Fei; Ling, Hui; Ang, Xiaohui

Natural compounds containing vanilloid and Michael acceptor moieties appear to possess anti-cancer and chemopreventive properties. The ginger constituent shogaol represents one such compound. In this study, the anti-cancer potential of a synthetic novel shogaol analog 3-phenyl-3-shogaol (3-Ph-3-SG) was assessed by evaluating its effects on signaling pathways. At non-toxic concentrations, 3-Ph-3-SG suppressed cancer cell invasion in MDA-MB-231 and MCF-7 breast carcinoma cells through inhibition of PMA-activated MMP-9 expression. At similar concentrations, 3-Ph-3-SG reduced expression of the inflammatory mediators nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and prostanglandin-E{sub 2} (PGE{sub 2}) in RAW 264.7 macrophage-like cells. Inhibition of cancermore » cell invasion and inflammation by 3-Ph-3-SG were mediated through suppression of the nuclear factor-kappaB (NF-κB) signaling pathway. The 3-Ph-3-SG also demonstrated cytoprotective effects by inducing the antioxidant response element (ARE)-driven genes NAD(P)H quinone oxidoreductase-1 (NQO1) and heme oxygenase-1 (HO-1). Cytoprotection by 3-Ph-3-SG was achieved at least partly through modification of cysteine residues in the E3 ubiquitin ligase substrate adaptor Kelch-like ECH-associated protein 1 (Keap1), which resulted in accumulation of transcription factor NF-E2 p45-related factor 2 (Nrf2). The activities of 3-Ph-3-SG were comparable to those of 6-shogaol, the most abundant naturally-occurring shogaol, and stronger than those of 4-hydroxyl-null deshydroxy-3-phenyl-3-shogaol, which attested the importance of the 4-hydroxy substituent in the vanilloid moiety for bioactivity. In summary, 3-Ph-3-SG is shown to possess activities that modulate stress-associated pathways relevant to multiple steps in carcinogenesis. Therefore, it warrants further investigation of this compound as a promising candidate for use in chemotherapeutic and chemopreventive strategies. - Highlights: • Novel shogaol 3-phenyl-3-shogaol suppressed cancer cell invasion and inflammation. • Anti-invasive and anti-inflammatory effects were NF-κB-dependent. • 3-Phenyl-3-shogaol induced ARE-driven genes to achieve cytoprotection. • Cytoprotective effects were brought about by modification of cysteines in Keap1. • Chemopreventive activities of 3-phenyl-3-shogaol and 6-shogaol were comparable.« less

Red (660 nm) or near-infrared (810 nm) photobiomodulation stimulates, while blue (415 nm), green (540 nm) light inhibits proliferation in human adipose-derived stem cells.

PubMed

Wang, Yuguang; Huang, Ying-Ying; Wang, Yong; Lyu, Peijun; Hamblin, Michael R

2017-08-10

We previously showed that blue (415 nm) and green (540 nm) wavelengths were more effective in stimulating osteoblast differentiation of human adipose-derived stem cells (hASC), compared to red (660 nm) and near-infrared (NIR, 810 nm). Intracellular calcium was higher after blue/green, and could be inhibited by the ion channel blocker, capsazepine. In the present study we asked what was the effect of these four wavelengths on proliferation of the hASC? When cultured in proliferation medium there was a clear difference between blue/green which inhibited proliferation and red/NIR which stimulated proliferation, all at 3 J/cm 2 . Blue/green reduced cellular ATP, while red/NIR increased ATP in a biphasic manner. Blue/green produced a bigger increase in intracellular calcium and reactive oxygen species (ROS). Blue/green reduced mitochondrial membrane potential (MMP) and lowered intracellular pH, while red/NIR had the opposite effect. Transient receptor potential vanilloid 1 (TRPV1) ion channel was expressed in hADSC, and the TRPV1 ligand capsaicin (5uM) stimulated proliferation, which could be abrogated by capsazepine. The inhibition of proliferation caused by blue/green could also be abrogated by capsazepine, and by the antioxidant, N-acetylcysteine. The data suggest that blue/green light inhibits proliferation by activating TRPV1, and increasing calcium and ROS.

Pharmacological profiling of the TRPV3 channel in recombinant and native assays.

PubMed

Grubisha, Olivera; Mogg, Adrian J; Sorge, Jessica L; Ball, Laura-Jayne; Sanger, Helen; Ruble, Cara L A; Folly, Elizabeth A; Ursu, Daniel; Broad, Lisa M

2014-05-01

Transient receptor potential vanilloid subtype 3 (TRPV3) is implicated in nociception and certain skin conditions. As such, it is an attractive target for pharmaceutical research. Understanding of endogenous TRPV3 function and pharmacology remains elusive as selective compounds and native preparations utilizing higher throughput methodologies are lacking. In this study, we developed medium-throughput recombinant and native cellular assays to assess the detailed pharmacological profile of human, rat and mouse TRPV3 channels. Medium-throughput cellular assays were developed using a Ca(2+) -sensitive dye and a fluorescent imaging plate reader. Human and rat TRPV3 pharmacology was examined in recombinant cell lines, while the mouse 308 keratinocyte cell line was used to assess endogenous TRPV3 activity. A recombinant rat TRPV3 cellular assay was successfully developed after solving a discrepancy in the published rat TRPV3 protein sequence. A medium-throughput, native, mouse TRPV3 keratinocyte assay was also developed and confirmed using genetic approaches. Whereas the recombinant human and rat TRPV3 assays exhibited similar agonist and antagonist profiles, the native mouse assay showed important differences, namely, TRPV3 activity was detected only in the presence of potentiator or during agonist synergy. Furthermore, the native assay was more sensitive to block by some antagonists. Our findings demonstrate similarities but also notable differences in TRPV3 pharmacology between recombinant and native systems. These findings offer insights into TRPV3 function and these assays should aid further research towards developing TRPV3 therapies. © 2013 The British Pharmacological Society.

Downregulated Expression of TRPV2 in Peripheral Blood Cells following Acute Myocardial Infarction Is Inversely Correlated with Serum Levels of CRP and Troponin I.

PubMed

Rozenbaum, Zach; Cohen, Lena; Bigelman, Einat; Shacham, Yacov; Keren, Gad; Entin-Meer, Michal

We have recently shown that the transient receptor potential vanilloid 2 (TRPV2) channel is exclusively upregulated in rat/murine peri-infarct monocytes/macrophages following an acute myocardial infarction (AMI), and that this overexpression might be detrimental for cardiac recovery. We aimed to characterize the expression levels of TRPV2 in peripheral blood mononuclear cells (PBMCs) of AMI patients relative to individuals with normal coronaries, and to analyze potential associations with inflammatory and cardiac ischemic markers. Patients who underwent coronary angiography due to AMI or chest pain were prospectively included. PBMCs were isolated from whole blood by Ficoll gradient centrifugation. TRPV2 expression was analyzed by real-time PCR. C-reactive protein (CRP) and troponin I (TpI) levels were determined at the central chemistry laboratory; interleukin 6 and insulin-like growth factor (IGF)-1 levels were tested by ELISA. Following AMI, the number of TRPV2-expressing PBMCs was reduced when compared to in patients with normal coronaries. An inverse correlation was documented between the numbers of circulating macrophages and TRPV2 expression. Additionally, TRPV2 expression was inversely correlated with CRP and TpI and directly correlated with serum IGF-1. We assume that peripheral TRPV2 downregulation occurs concomitantly with the accumulation of TRPV2-white blood cells in the peri-infarct zone. TRPV2 may thus represent a novel target for treatment in the acute phase after MI. © 2018 S. Karger AG, Basel.

Esophageal cancer stem cells are suppressed by tranilast, a TRPV2 channel inhibitor.

PubMed

Shiozaki, Atsushi; Kudou, Michihiro; Ichikawa, Daisuke; Fujiwara, Hitoshi; Shimizu, Hiroki; Ishimoto, Takeshi; Arita, Tomohiro; Kosuga, Toshiyuki; Konishi, Hirotaka; Komatsu, Shuhei; Okamoto, Kazuma; Marunaka, Yoshinori; Otsuji, Eigo

2018-02-01

Recent evidence suggests that the targeting of membrane proteins specifically activated in cancer stem cells (CSCs) is an important strategy for cancer therapy. The objectives of the present study were to investigate the expression and activity of ion-transport-related molecules in the CSCs of esophageal squamous cell carcinoma. Cells exhibiting strong aldehyde dehydrogenase 1 family member A1 (ALDH1A1) activity were isolated from TE8 cells by fluorescence-activated cell sorting, and CSCs were then generated with the sphere formation assay. The gene expression profiles of CSCs were examined by microarray analysis. Among TE8 cells, ALDH1A1 messenger RNA and protein levels were higher in CSCs than in non-CSCs. The CSCs obtained were resistant to cisplatin and had the ability to redifferentiate. The results of the microarray analysis revealed that the expression of 50 genes encoding plasma membrane proteins was altered in CSCs, whereas that of several genes related to ion channels, including transient receptor potential vanilloid 2 (TRPV2), was upregulated. The TRPV2 inhibitor tranilast was more cytotoxic at a lower concentration in CSCs than in non-CSCs, and effectively decreased the number of tumorspheres. Furthermore, tranilast significantly decreased the cell population that strongly expressed ALDH1A1 among TE8 cells. The results of the present study suggest that TRPV2 is involved in the maintenance of CSCs, and that its specific inhibitor, tranilast, has potential as a targeted therapeutic agent against esophageal squamous cell carcinoma.

Fructus ligustri lucidi ethanol extract improves bone mineral density and properties through modulating calcium absorption-related gene expression in kidney and duodenum of growing rats.

PubMed

Feng, Xin; Lyu, Ying; Wu, Zhenghao; Fang, Yuehui; Xu, Hao; Zhao, Pengling; Xu, Yajun; Feng, Haotian

2014-04-01

Optimizing peak bone mass in early life is one of key preventive strategies against osteoporosis. Fructus ligustri lucidi (FLL), the fruit of Ligustrum lucidum Ait., is a commonly prescribed herb in many kidney-tonifying traditional Chinese medicinal formulas to alleviate osteoporosis. Previously, FLL extracts have been shown to have osteoprotective effect in aged or ovariectomized rats. In the present study, we investigated the effects of FLL ethanol extract on bone mineral density (BMD) and mechanical properties in growing male rats and explored the underlying mechanisms. Male weaning Sprague-Dawley rats were randomized into four groups and orally administrated for 4 months an AIN-93G formula-based diet supplementing with different doses of FLL ethanol extract (0.40, 0.65, and 0.90 %) or vehicle control, respectively. Then calcium balance, serum level of Ca, P, 25(OH)2D3, 1,25(OH)2D3, osteocalcin (OCN), C-terminal telopeptide of type I collagen (CTX-I), and parathyroid hormone, bone microarchitecture, and calcium absorption-related genes expression in duodenum and kidney were analyzed. The results demonstrated that FLL ethanol extract increased BMD of growing rats and improved their bone microarchitecture and mechanical properties. FLL ethanol extract altered bone turnover, as evidenced by increasing a bone formation maker, OCN, and decreasing a bone resorption maker, CTX-I. Intriguingly, both Ca absorption and Ca retention rate were elevated by FLL ethanol extract treatment, possibly through the mechanisms of up-regulating the transcriptions of calcitropic genes in kidney (1α-hydroxylase) and duodenum (vitamin D receptor, calcium transporter calbindin-D9k, and transient receptor potential vanilloid 6). In conclusion, FLL ethanol extract increased bone mass gain and improved bone properties via modulating bone turnover and up-regulating calcium absorption-related gene expression in kidney and duodenum, which could then activate 1,25(OH)2D3-dependent calcium transport in male growing rats.

Klotho Up-regulates Renal Calcium Channel Transient Receptor Potential Vanilloid 5 (TRPV5) by Intra- and Extracellular N-glycosylation-dependent Mechanisms*

PubMed Central

Wolf, Matthias T. F.; An, Sung-Wan; Nie, Mingzhu; Bal, Manjot S.; Huang, Chou-Long

2014-01-01

The anti-aging protein Klotho is a type 1 membrane protein produced predominantly in the distal convoluted tubule. The ectodomain of Klotho is cleaved and secreted into the urine to regulate several ion channels and transporters. Secreted Klotho (sKL) up-regulates the TRPV5 calcium channel from the cell exterior by removing sialic acids from N-glycan of the channel and inhibiting its endocytosis. Because TRPV5 and Klotho coexpress in the distal convoluted tubule, we investigated whether Klotho regulates TRPV5 action from inside the cell. Whole-cell TRPV5-mediated channel activity was recorded in HEK cells coexpressing TRPV5 and sKL or membranous Klotho (mKL). Transfection of sKL, but not mKL, produced detectable Klotho protein in cell culture media. As for sKL, mKL increased TRPV5 current density. The role of sialidase activity of mKL acting inside is supported by findings that mutations of putative sialidase activity sites in sKL and mKL abrogated the regulation of TRPV5 but that the extracellular application of a sialidase inhibitor prevented the regulation of TRPV5 by sKL only. Mechanistically, coexpression with a dominant-negative dynamin II prevented the regulation of TRPV5 by sKL but not by mKL. In contrast, blocking forward trafficking by brefeldin A prevented the effect with mKL but not with sKL. Therefore, Klotho up-regulates TRPV5 from both the inside and outside of cells. The intracellular action of Klotho is likely due to enhanced forward trafficking of channel proteins, whereas the extracellular action is due to inhibition of endocytosis. Both effects involve putative Klotho sialidase activity. These effects of Klotho may play important roles regarding calcium reabsorption in the kidney. PMID:25378396

Activation of TRPV4 by dietary apigenin antagonizes renal fibrosis in deoxycorticosterone acetate (DOCA)-salt-induced hypertension.

PubMed

Wei, Xing; Gao, Peng; Pu, Yunfei; Li, Qiang; Yang, Tao; Zhang, Hexuan; Xiong, Shiqiang; Cui, Yuanting; Li, Li; Ma, Xin; Liu, Daoyan; Zhu, Zhiming

2017-04-01

Hypertension-induced renal fibrosis contributes to the progression of chronic kidney disease, and apigenin, an anti-hypertensive flavone that is abundant in celery, acts as an agonist of transient receptor potential vanilloid 4 (TRPV4). However, whether apigenin reduces hypertension-induced renal fibrosis, as well as the underlying mechanism, remains elusive. In the present study, the deoxycorticosterone acetate (DOCA)-salt hypertension model was established in male Sprague-Dawley rats that were treated with apigenin or vehicle for 4 weeks. Apigenin significantly attenuated the DOCA-salt-induced structural and functional damage to the kidney, which was accompanied by reduced expression of transforming growth factor-β1 (TGF-β1)/Smad2/3 signaling pathway and extracellular matrix proteins. Immunochemistry, cell-attached patch clamp and fluorescent Ca 2+ imaging results indicated that TRPV4 was expressed and activated by apigenin in both the kidney and renal cells. Importantly, knockout of TRPV4 in mice abolished the beneficial effects of apigenin that were observed in the DOCA-salt hypertensive rats. Additionally, apigenin directly inhibited activation of the TGF-β1/Smad2/3 signaling pathway in different renal tissues through activation of TRPV4 regardless of the type of pro-fibrotic stimulus. Moreover, the TRPV4-mediated intracellular Ca 2+ influx activated the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) pathway, which inhibited the TGF-β1/Smad2/3 signaling pathway. In summary, dietary apigenin has beneficial effects on hypertension-induced renal fibrosis through the TRPV4-mediated activation of AMPK/SIRT1 and inhibition of the TGF-β1/Smad2/3 signaling pathway. This work suggests that dietary apigenin may represent a promising lifestyle modification for the prevention of hypertension-induced renal damage in populations that consume a high-sodium diet. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

TRPV4 activation mediates flow-induced nitric oxide production in the rat thick ascending limb

PubMed Central

Garvin, Jeffrey L.

2014-01-01

Nitric oxide (NO) regulates renal function. Luminal flow stimulates NO production in the thick ascending limb (TAL). Transient receptor potential vanilloid 4 (TRPV4) is a mechano-sensitive channel activated by luminal flow in different types of cells. We hypothesized that TRPV4 mediates flow-induced NO production in the rat TAL. We measured NO production in isolated, perfused rat TALs using the fluorescent dye DAF FM. Increasing luminal flow from 0 to 20 nl/min stimulated NO from 8 ± 3 to 45 ± 12 arbitrary units (AU)/min (n = 5; P < 0.05). The TRPV4 antagonists, ruthenium red (15 μmol/l) and RN 1734 (10 μmol/l), blocked flow-induced NO production. Also, luminal flow did not increase NO production in the absence of extracellular calcium. We also studied the effect of luminal flow on NO production in TALs transduced with a TRPV4shRNA. In nontransduced TALs luminal flow increased NO production by 47 ± 17 AU/min (P < 0.05; n = 5). Similar to nontransduced TALs, luminal flow increased NO production by 39 ± 11 AU/min (P < 0.03; n = 5) in TALs transduced with a control negative sequence-shRNA while in TRPV4shRNA-transduced TALs, luminal flow did not increase NO production (Δ10 ± 15 AU/min; n = 5). We then tested the effect of two different TRPV4 agonists on NO production in the absence of luminal flow. 4α-Phorbol 12,13-didecanoate (1 μmol/l) enhanced NO production by 60 ± 11 AU/min (P < 0.002; n = 7) and GSK1016790A (10 ηmol/l) increased NO production by 52 ± 15 AU/min (P < 0.03; n = 5). GSK1016790A (10 ηmol/l) did not stimulate NO production in TRPV4shRNA-transduced TALs. We conclude that activation of TRPV4 channels mediates flow-induced NO production in the rat TAL. PMID:24966090

Impact of a folic acid-enriched diet on urinary tract function in mice treated with testosterone and estradiol

PubMed Central

Keil, Kimberly P.; Abler, Lisa L.; Altmann, Helene M.; Wang, Zunyi; Wang, Peiqing; Ricke, William A.; Bjorling, Dale E.

2015-01-01

Aging men are susceptible to developing lower urinary tract symptoms, but the underlying etiology is unknown and the influence of dietary and environmental factors on them is unclear. We tested whether a folic acid-enriched diet changed urinary tract physiology and biology in control male mice and male mice with urinary dysfunction induced by exogenous testosterone and estradiol (T+E2), which mimics changing hormone levels in aging humans. T+E2 treatment increased mouse urine output, time between voiding events, and bladder capacity and compliance. Consumption of a folic acid-enriched diet moderated these changes without decreasing prostate wet weight or threshold voiding pressure. One potential mechanism for these changes involves water balance. T+E2 treatment increases plasma concentrations of anti-diuretic hormone, which is offset at least in part by a folic acid-enriched diet. Another potential mechanism involves neural control of micturition. The folic acid-enriched diet, fed to T+E2-treated mice, increased voiding frequency in response to intravesicular capsaicin infusion and increased mRNA abundance of the capsaicin-sensitive cation channel transient receptor potential vanilloid subfamily member 1 (Trpv1) in L6 and S1 dorsal root ganglia (DRG) neurons. T+E2 treatment and a folic acid-enriched diet also modified DNA methylation, which is capable of altering gene expression. We found the enriched diet increased global DNA methylation in dorsal and ventral prostate and L6 and S1 DRG. Our results are consistent with folic acid acting to slow or reverse T+E2-mediated alteration in urinary function in part by normalizing water balance and enhancing or preserving afferent neuronal function. PMID:25855514

TRPV2 activation induces apoptotic cell death in human T24 bladder cancer cells: a potential therapeutic target for bladder cancer.

PubMed

Yamada, Takahiro; Ueda, Takashi; Shibata, Yasuhiro; Ikegami, Yosuke; Saito, Masaki; Ishida, Yusuke; Ugawa, Shinya; Kohri, Kenjiro; Shimada, Shoichi

2010-08-01

To investigate the functional expression of the transient receptor potential vanilloid 2 (TRPV2) channel protein in human urothelial carcinoma (UC) cells and to determine whether calcium influx into UC cells through TRPV2 is involved in apoptotic cell death. The expression of TRPV2 mRNA in bladder cancer cell lines (T24, a poorly differentiated UC cell line and RT4, a well-differentiated UC cell line) was analyzed using reverse transcriptase-polymerase chain reaction. The calcium permeability of TRPV2 channels in T24 cells was investigated using a calcium imaging assay that used cannabidiol (CBD), a relatively selective TRPV2 agonist, and ruthenium red (RuR), a nonselective TRPV channel antagonist. The death of T24 or RT4 cells in the presence of CBD was evaluated using a cellular viability assay. Apoptosis of T24 cells caused by CBD was confirmed using an annexin-V assay and small interfering RNA (siRNA) silencing of TRPV2. TRPV2 mRNA was abundantly expressed in T24 cells. The expression level in UC cells was correlated with high-grade disease. The administration of CBD increased intracellular calcium concentrations in T24 cells. In addition, the viability of T24 cells progressively decreased with increasing concentrations of CBD, whereas RT4 cells were mostly unaffected. Cell death occurred via apoptosis caused by continuous influx of calcium through TRPV2. TRPV2 channels in UC cells are calcium-permeable and the regulation of calcium influx through these channels leads directly to the death of UC cells. TRPV2 channels in UC cells may be a potential new therapeutic target, especially in higher-grade UC cells. Copyright 2010 Elsevier Inc. All rights reserved.

Expression of Cannabinoid Receptors in Human Osteoarthritic Cartilage: Implications for Future Therapies.

PubMed

Dunn, Sara L; Wilkinson, Jeremy Mark; Crawford, Aileen; Bunning, Rowena A D; Le Maitre, Christine L

2016-01-01

Introduction: Cannabinoids have shown to reduce joint damage in animal models of arthritis and reduce matrix metalloproteinase expression in primary human osteoarthritic (OA) chondrocytes. The actions of cannabinoids are mediated by a number of receptors, including cannabinoid receptors 1 and 2 (CB1 and CB2), G-protein-coupled receptors 55 and 18 (GPR55 and GPR18), transient receptor potential vanilloid-1 (TRPV1), and peroxisome proliferator-activated receptors alpha and gamma (PPARα and PPARγ). However, to date very few studies have investigated the expression and localization of these receptors in human chondrocytes, and expression during degeneration, and thus their potential in clinical applications is unknown. Methods: Human articular cartilage from patients with symptomatic OA was graded histologically and the expression and localization of cannabinoid receptors within OA cartilage and underlying bone were determined immunohistochemically. Expression levels across regions of cartilage and changes with degeneration were investigated. Results: Expression of all the cannabinoid receptors investigated was observed with no change with grade of degeneration seen in the expression of CB1, CB2, GPR55, PPARα, and PPARγ. Conversely, the number of chondrocytes within the deep zone of cartilage displaying immunopositivity for GPR18 and TRPV1 was significantly decreased in degenerate cartilage. Receptor expression was higher in chondrocytes than in osteocytes in the underlying bone. Conclusions: Chondrocytes from OA joints were shown to express a wide range of cannabinoid receptors even in degenerate tissues, demonstrating that these cells could respond to cannabinoids. Cannabinoids designed to bind to receptors inhibiting the catabolic and pain pathways within the arthritic joint, while avoiding psychoactive effects, could provide potential arthritis therapies.

TRPV2 knockout mice demonstrate an improved cardiac performance following myocardial infarction due to attenuated activity of peri-infarct macrophages.

PubMed

Entin-Meer, Michal; Cohen, Lena; Hertzberg-Bigelman, Einat; Levy, Ran; Ben-Shoshan, Jeremy; Keren, Gad

2017-01-01

We have recently shown that the expression of the transient receptor potential vanilloid 2 channel, TRPV2, is upregulated in the peri-infarct zone 3-5 days following an acute myocardial infarction (AMI). Further analysis has demonstrated that invading monocytes maturing to macrophages merely harbor the documented elevated expression of this channel. Assess cardiac function in TRPV2-KO mice compared to TRPV2-WT following AMI and analyze the potential involvement of TRPV2-expressing macrophages in the recovery process. TRPV2-KO or WT mice were induced with AMI by ligation of the left anterior descending artery (LAD). In another set of experiments, TRPV2-KO mice induced with AMI, were intravenously (IV) injected with WT or TRPV2-KO peritoneal macrophages in order to directly assess the potential contribution of TRPV2-expressing macrophages to cardiac healing. Cardiac parameters were obtained by echocardiography 1 day and 30 days post infarction. The relative changes in the ejection fraction (EF) and additional cardiac parameters between baseline (day 1) and day 30 were calculated and statistical significance was determined (SPSS). The in vivo study showed that while EF was significantly decreased in the WT animals between baseline and day 30, EF was only slightly and insignificantly reduced in the KO animals. Likewise LVESD and LVESA were significantly modified exclusively in the WT animals. Moreover, intravenous administration of peritoneal WT macrophages, but not KO macrophages, significantly reduced survival of post-MI TRPV2-KO mice. The data suggest that knockout of the TRPV2 channel may attenuate macrophage-dependent pro-inflammatory processes and result in better cardiac recovery. TRPV2 may thus represent a novel therapeutic target for treatment of patients undergoing an acute MI.

Overactivity of Liver-Related Neurons in the Paraventricular Nucleus of the Hypothalamus: Electrophysiological Findings in db/db Mice

PubMed Central

Gao, Hong; Molinas, Adrien J.R.; Qiao, Xin

2017-01-01

Preautonomic neurons in the paraventricular nucleus (PVN) of the hypothalamus play a large role in the regulation of hepatic functions via the autonomic nervous system. Activation of hepatic sympathetic nerves increases glucose and lipid metabolism and contributes to the elevated hepatic glucose production observed in the type 2 diabetic condition. This augmented sympathetic output could originate from altered activity of liver-related PVN neurons. Remarkably, despite the importance of the brain-liver pathway, the cellular properties of liver-related neurons are not known. In this study, we provide the first evidence of overall activity of liver-related PVN neurons. Liver-related PVN neurons were identified with a retrograde, trans-synaptic, viral tracer in male lean and db/db mice and whole-cell patch-clamp recordings were conducted. In db/db mice, the majority of liver-related PVN neurons fired spontaneously; whereas, in lean mice the majority of liver-related PVN neurons were silent, indicating that liver-related PVN neurons are more active in db/db mice. Persistent, tonic inhibition was identified in liver-related PVN neurons; although, the magnitude of tonic inhibitory control was not different between lean and db/db mice. In addition, our study revealed that the transient receptor potential vanilloid type 1-dependent increase of excitatory neurotransmission was reduced in liver-related PVN neurons of db/db mice. These findings demonstrate plasticity of liver-related PVN neurons and a shift toward excitation in a diabetic mouse model. Our study suggests altered autonomic circuits at the level of the PVN, which can contribute to autonomic dysfunction and dysregulation of neural control of hepatic functions including glucose metabolism. SIGNIFICANCE STATEMENT A growing body of evidence suggests the importance of the autonomic control in the regulation of hepatic metabolism, which plays a major role in the development and progression of type 2 diabetes mellitus. Despite the importance of the brain-liver pathway, the overall activity of liver-related neurons in control and diabetic conditions is not known. This is a significant gap in knowledge, which prevents developing strategies to improve glucose homeostasis via altering the brain-liver pathway. One of the key findings of our study is the overall shift toward excitation in liver-related hypothalamic neurons in the diabetic condition. This overactivity may be one of the underlying mechanisms of elevated sympathetic activity known in metabolically compromised patients and animal models. PMID:29038244

Overactivity of Liver-Related Neurons in the Paraventricular Nucleus of the Hypothalamus: Electrophysiological Findings in db/db Mice.

PubMed

Gao, Hong; Molinas, Adrien J R; Miyata, Kayoko; Qiao, Xin; Zsombok, Andrea

2017-11-15

Preautonomic neurons in the paraventricular nucleus (PVN) of the hypothalamus play a large role in the regulation of hepatic functions via the autonomic nervous system. Activation of hepatic sympathetic nerves increases glucose and lipid metabolism and contributes to the elevated hepatic glucose production observed in the type 2 diabetic condition. This augmented sympathetic output could originate from altered activity of liver-related PVN neurons. Remarkably, despite the importance of the brain-liver pathway, the cellular properties of liver-related neurons are not known. In this study, we provide the first evidence of overall activity of liver-related PVN neurons. Liver-related PVN neurons were identified with a retrograde, trans-synaptic, viral tracer in male lean and db/db mice and whole-cell patch-clamp recordings were conducted. In db/db mice, the majority of liver-related PVN neurons fired spontaneously; whereas, in lean mice the majority of liver-related PVN neurons were silent, indicating that liver-related PVN neurons are more active in db/db mice. Persistent, tonic inhibition was identified in liver-related PVN neurons; although, the magnitude of tonic inhibitory control was not different between lean and db/db mice. In addition, our study revealed that the transient receptor potential vanilloid type 1-dependent increase of excitatory neurotransmission was reduced in liver-related PVN neurons of db/db mice. These findings demonstrate plasticity of liver-related PVN neurons and a shift toward excitation in a diabetic mouse model. Our study suggests altered autonomic circuits at the level of the PVN, which can contribute to autonomic dysfunction and dysregulation of neural control of hepatic functions including glucose metabolism. SIGNIFICANCE STATEMENT A growing body of evidence suggests the importance of the autonomic control in the regulation of hepatic metabolism, which plays a major role in the development and progression of type 2 diabetes mellitus. Despite the importance of the brain-liver pathway, the overall activity of liver-related neurons in control and diabetic conditions is not known. This is a significant gap in knowledge, which prevents developing strategies to improve glucose homeostasis via altering the brain-liver pathway. One of the key findings of our study is the overall shift toward excitation in liver-related hypothalamic neurons in the diabetic condition. This overactivity may be one of the underlying mechanisms of elevated sympathetic activity known in metabolically compromised patients and animal models. Copyright © 2017 the authors 0270-6474/17/3711140-11$15.00/0.

H89 dihydrochloride hydrate and calphostin C lower the body temperature through TRPV1.

PubMed

Bao, Dongyan; Zhao, Wenqing; Dai, Congcong; Wan, Hongmei; Cao, Yu

2018-01-01

The transient receptor potential vanilloid (TRPV1) serves as a negative regulator of body temperature, and during fever conditions its expression can lead to a decrease in temperature. TRPV1 is regulated by a variety of enzymes; however, it is currently unclear whether the regulation of TRPV1 phosphorylation may serve a role in the increase in TRPV1 expression during fever. In the present study, using an in vivo experimental method, rat brain ventricles were injected with the protein kinase A (PKA) antagonist, H89, and the protein kinase C (PKC) antagonist, calphostin C, and fever was induced using lipopolysaccharide (LPS) in order to detect the expression of TRPV1 and phosphorylated (p‑)TRPV1, the intracellular Ca2+ concentration [(Ca2+)i] of hypothalami and rat body temperature. The results demonstrated that following the generation of fever using LPS, the expressions of TRPV1 and p‑TRPV1, and hypothalamic [Ca2+]i markedly increased. In addition, following an injection with the PKA or PKC antagonist, the temperature increased further due to the inhibition of p‑TRPV1. Thus, it was hypothesized that PKA and PKC may be involved in TRPV1 phosphorylation, resulting in a temperature reduction during LPS‑induced fever conditions.

Effects of Capsaicin on Older Patients with Oropharyngeal Dysphagia: A Double-Blind, Placebo-Controlled, Crossover Study.

PubMed

Nakato, Rui; Manabe, Noriaki; Shimizu, Sayako; Hanayama, Kozo; Shiotani, Akiko; Hata, Jiro; Haruma, Ken

2017-01-01

The standard of care for older patients with oropharyngeal dysphagia (OD) is poor. Stimulation of transient receptor potential vanilloid 1 might become a pharmacological strategy for these patients. This study aimed to compare the therapeutic effect of film food containing 0.75 µg of capsaicin in these patients. In a crossover, randomized trial, 49 patients with OD were provided capsaicin or identical placebo at least 7 days apart. Patients' reported symptoms during repeated swallowing, the volume, pH and substance P (SP) concentrations in saliva, and cervical esophageal wall motion evaluated by ultrasonographic tissue Doppler imaging were obtained before and after capsaicin or placebo administration. Significantly more patients with OD who took capsaicin experienced improvement in symptoms than those who took placebo. Salivary SP levels were significantly increased after capsaicin administration compared with placebo in the effective group. The duration of cervical esophageal wall opening was significantly shorter in capsaicin administration in the effective group. Furthermore, a significant negative correlation was found between the duration of cervical esophageal wall opening and salivary SP levels. Elevated salivary SP concentrations stimulated by capsaicin greatly improve the safety and efficacy of swallowing, and shorten the swallow response in older patients with OD. © 2017 S. Karger AG, Basel.

Chili Peppers, Curcumins, and Prebiotics in Gastrointestinal Health and Disease.

PubMed

Patcharatrakul, Tanisa; Gonlachanvit, Sutep

2016-04-01

There is growing evidence for the role of several natural products as either useful agents or adjuncts in the management of functional GI disorders (FGIDs). In this review, we examine the medical evidence for three such compounds: chili, a culinary spice; curcumin, another spice and active derivative of a root bark; and prebiotics, which are nondigestible food products. Chili may affect the pathogenesis of abdominal pain especially in functional dyspepsia and cause other symptoms. It may have a therapeutic role in FGIDs through desensitization of transient receptor potential vanilloid-1 receptor. Curcumin, the active ingredient of turmeric rhizome, has been shown in several preclinical studies and uncontrolled clinical trials as having effects on gut inflammation, gut permeability and the brain-gut axis, especially in FGIDs. Prebiotics, the non-digestible food ingredients in dietary fiber, may serve as nutrients and selectively stimulate the growth and/or activity of certain colonic bacteria. The net effect of this change on colonic microbiota may lead to the production of acidic metabolites and other compounds that help to reduce the production of toxins and suppress the growth of harmful or disease-causing enteric pathogens. Although some clinical benefit in IBS has been shown, high dose intake of prebiotics may cause more bloating from bacterial fermentation.

Neonatal capsaicin treatment in rats affects TRPV1-related noxious heat sensation and circadian body temperature rhythm.

PubMed

Jeong, Keun-Yeong; Seong, Jinsil

2014-06-15

The transient receptor potential vanilloid 1 (TRPV1) is a cation channel that serves as a polymodal detector of noxious stimuli such as capsaicin. Therefore, capsaicin treatment has been used to investigate the physiological function of TRPV1. Here, we report physiological changes induced by treating neonatal rats with capsaicin. Capsaicin (50mg/kg) (cap-treated) or vehicle (vehicle-treated) was systemically administered to newborn SD rat pups within 48 h after birth. TRPV1 expression, intake volume of capsaicin water, and noxious heat sensation were measured 6 weeks after capsaicin treatment. Circadian body temperature and locomotion were recorded by biotelemetry. Expression of Per1, Per2, Bmal1 and Hsf1 (clock genes) was also investigated. Neonatal capsaicin treatment not only decreased TRPV1 expression but also induced desensitization to noxious heat stimuli. Circadian body temperature of cap-treated rats increased significantly compared with that of vehicle-treated rats. Additionally, the amplitude of the circadian body temperature was reversed in cap-treated rats. Expression of the hypothalamic Hsf1 and liver Per2 clock genes followed a similar trend. Therefore, we suggest that these findings will be useful in studying various physiological mechanisms related to TRPV1. Copyright © 2014 Elsevier B.V. All rights reserved.

Induction of therapeutic hypothermia by pharmacological modulation of temperature-sensitive TRP channels: theoretical framework and practical considerations.

PubMed

Feketa, Viktor V; Marrelli, Sean P

2015-01-01

Therapeutic hypothermia has emerged as a remarkably effective method of neuroprotection from ischemia and is being increasingly used in clinics. Accordingly, it is also a subject of considerable attention from a basic scientific research perspective. One of the fundamental problems, with which current studies are concerned, is the optimal method of inducing hypothermia. This review seeks to provide a broad theoretical framework for approaching this problem, and to discuss how a novel promising strategy of pharmacological modulation of the thermosensitive ion channels fits into this framework. Various physical, anatomical, physiological and molecular aspects of thermoregulation, which provide the foundation for this text, have been comprehensively reviewed and will not be discussed exhaustively here. Instead, the first part of the current review, which may be helpful for a broader readership outside of thermoregulation research, will build on this existing knowledge to outline possible opportunities and research directions aimed at controlling body temperature. The second part, aimed at a more specialist audience, will highlight the conceptual advantages and practical limitations of novel molecular agents targeting thermosensitive Transient Receptor Potential (TRP) channels in achieving this goal. Two particularly promising members of this channel family, namely TRP melastatin 8 (TRPM8) and TRP vanilloid 1 (TRPV1), will be discussed in greater detail.

2-(3-Fluoro-4-methylsulfonylaminophenyl) Propanamides as Potent Transient Receptor Potential Vanilloid 1 (TRPV1) Antagonists: Structure Activity Relationships of 2-Amino Derivatives in the N-(6-trifluoromethyl-pyridin-3-ylmethyl) C-region

PubMed Central

Kim, Myeong Seop; Ryu, HyungChul; Kang, Dong Wook; Cho, Seong-Hee; Seo, Sejin; Park, Young Soo; Kim, Mi-Yeon; Kwak, Eun Joo; Kim, Yong Soo; Bhondwe, Rahul S.; Kim, Ho Shin; Park, Seul-gi; Son, Karam; Choi, Sun; DeAndrea-Lazarus, Ian; Pearce, Larry V.; Blumberg, Peter M.; Frank, Robert; Bahrenberg, Gregor; Stockhausen, Hannelore; Kögel, Babette Y.; Schiene, Klaus; Christoph, Thomas; Lee, Jeewoo

2012-01-01

A series of N-(2-amino-6-trifluoromethyl-pyridin-3-ylmethyl) 2-(3-fluoro-4-methylsulfonylaminophenyl) propanamides were designed combining previously identified pharmacophoric elements and evaluated as hTRPV1 antagonists. The SAR analysis indicated that specific hydrophobic interactions of the 2-amino substituents in the C-region of the ligand were critical for high hTRPV1binding potency. In particular, compound 49S was an excellent TRPV1 antagonist (Ki(CAP) = 0.2 nM; IC50(pH) = 6.3 nM) and was thus ca. 100- and 20-fold more potent, respectively, than the parent compounds 2 and 3 for capsaicin antagonism. Furthermore, it demonstrated strong analgesic activity in the rat neuropathic model superior to 2 with almost no side effects. Compound 49S antagonized capsaicin induced hypothermia in mice, but showed TRPV1-related hyperthermia. The basis for the high potency of 49S compared to 2 is suggested by docking analysis with our hTRPV1 homology model in which the 4-methylpiperidinyl group in the C-region of 49S made additional hydrophobic interactions with the hydrophobic region. PMID:22957803

Vanilloid Receptor-1 (TRPV1) Expression and Function in the Vasculature of the Rat

PubMed Central

Czikora, Ágnes; Pásztor, Enikő T.; Dienes, Beatrix; Bai, Péter; Csernoch, László; Rutkai, Ibolya; Csató, Viktória; Mányiné, Ivetta S.; Pórszász, Róbert; Édes, István; Papp, Zoltán; Boczán, Judit

2014-01-01

Transient receptor potential (TRP) cation channels are emerging in vascular biology. In particular, the expression of the capsaicin receptor (TRPV1) was reported in vascular smooth muscle cells. This study characterized the arteriolar TRPV1 function and expression in the rat. TRPV1 mRNA was expressed in various vascular beds. Six commercially available antibodies were tested for TRPV1 specificity. Two of them were specific (immunostaining was abolished by blocking peptides) for neuronal TRPV1 and one recognized vascular TRPV1. TRPV1 was expressed in blood vessels in the skeletal muscle, mesenteric and skin tissues, as well as in the aorta and carotid arteries. TRPV1 expression was found to be regulated at the level of individual blood vessels, where some vessels expressed, while others did not express TRPV1 in the same tissue sections. Capsaicin (a TRPV1 agonist) evoked constrictions in skeletal muscle arteries and in the carotid artery, but had no effect on the femoral and mesenteric arteries or the aorta. In blood vessels, TRPV1 expression was detected in most of the large arteries, but there were striking differences at level of the small arteries. TRPV1 activity was suppressed in some isolated arteries. This tightly regulated expression and function suggests a physiological role for vascular TRPV1. PMID:24217926

H89 dihydrochloride hydrate and calphostin C lower the body temperature through TRPV1

PubMed Central

Bao, Dongyan; Zhao, Wenqing; Dai, Congcong; Wan, Hongmei; Cao, Yu

2018-01-01

The transient receptor potential vanilloid (TRPV1) serves as a negative regulator of body temperature, and during fever conditions its expression can lead to a decrease in temperature. TRPV1 is regulated by a variety of enzymes; however, it is currently unclear whether the regulation of TRPV1 phosphorylation may serve a role in the increase in TRPV1 expression during fever. In the present study, using an in vivo experimental method, rat brain ventricles were injected with the protein kinase A (PKA) antagonist, H89, and the protein kinase C (PKC) antagonist, calphostin C, and fever was induced using lipopolysaccharide (LPS) in order to detect the expression of TRPV1 and phosphorylated (p-)TRPV1, the intracellular Ca2+ concentration [(Ca2+)i] of hypothalami and rat body temperature. The results demonstrated that following the generation of fever using LPS, the expressions of TRPV1 and p-TRPV1, and hypothalamic [Ca2+]i markedly increased. In addition, following an injection with the PKA or PKC antagonist, the temperature increased further due to the inhibition of p-TRPV1. Thus, it was hypothesized that PKA and PKC may be involved in TRPV1 phosphorylation, resulting in a temperature reduction during LPS-induced fever conditions. PMID:29257197

On the mechanism of TBA block of the TRPV1 channel.

PubMed

Oseguera, Andrés Jara; Islas, León D; García-Villegas, Refugio; Rosenbaum, Tamara

2007-06-01

The transient receptor potential vanilloid 1 (TRPV1) channel is a nonselective cation channel activated by capsaicin and responsible for thermosensation. To date, little is known about the gating characteristics of these channels. Here we used tetrabutylammonium (TBA) to determine whether this molecule behaves as an ion conduction blocker in TRPV1 channels and to gain insight into the nature of the activation gate of this protein. TBA belongs to a family of classic potassium channel blockers that have been widely used as tools for determining the localization of the activation gate and the properties of the pore of several ion channels. We found TBA to be a voltage-dependent pore blocker and that the properties of block are consistent with an open-state blocker, with the TBA molecule binding to multiple open states, each with different blocker affinities. Kinetics of channel closure and burst-length analysis in the presence of blocker are consistent with a state-dependent blocking mechanism, with TBA interfering with closing of an activation gate. This activation gate may be located cytoplasmically with respect to the binding site of TBA ions, similar to what has been observed in potassium channels. We propose an allosteric model for TRPV1 activation and block by TBA, which explains our experimental data.

Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system.

PubMed

Kim, Minji; Goto, Tsuyoshi; Yu, Rina; Uchida, Kunitoshi; Tominaga, Makoto; Kano, Yuriko; Takahashi, Nobuyuki; Kawada, Teruo

2015-12-17

Brown adipose tissue (BAT) plays a central role in regulating energy homeostasis, and may provide novel strategies for the treatment of human obesity. BAT-mediated thermogenesis is regulated by mitochondrial uncoupling protein 1 (UCP1) in classical brown and ectopic beige adipocytes, and is controlled by sympathetic nervous system (SNS). Previous work indicated that fish oil intake reduces fat accumulation and induces UCP1 expression in BAT; however, the detailed mechanism of this effect remains unclear. In this study, we investigated the effect of fish oil on energy expenditure and the SNS. Fish oil intake increased oxygen consumption and rectal temperature, with concomitant upregulation of UCP1 and the β3 adrenergic receptor (β3AR), two markers of beige adipocytes, in the interscapular BAT and inguinal white adipose tissue (WAT). Additionally, fish oil intake increased the elimination of urinary catecholamines and the noradrenaline (NA) turnover rate in interscapular BAT and inguinal WAT. Furthermore, the effects of fish oil on SNS-mediated energy expenditure were abolished in transient receptor potential vanilloid 1 (TRPV1) knockout mice. In conclusion, fish oil intake can induce UCP1 expression in classical brown and beige adipocytes via the SNS, thereby attenuating fat accumulation and ameliorating lipid metabolism.

Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system

PubMed Central

Kim, Minji; Goto, Tsuyoshi; Yu, Rina; Uchida, Kunitoshi; Tominaga, Makoto; Kano, Yuriko; Takahashi, Nobuyuki; Kawada, Teruo

2015-01-01

Brown adipose tissue (BAT) plays a central role in regulating energy homeostasis, and may provide novel strategies for the treatment of human obesity. BAT-mediated thermogenesis is regulated by mitochondrial uncoupling protein 1 (UCP1) in classical brown and ectopic beige adipocytes, and is controlled by sympathetic nervous system (SNS). Previous work indicated that fish oil intake reduces fat accumulation and induces UCP1 expression in BAT; however, the detailed mechanism of this effect remains unclear. In this study, we investigated the effect of fish oil on energy expenditure and the SNS. Fish oil intake increased oxygen consumption and rectal temperature, with concomitant upregulation of UCP1 and the β3 adrenergic receptor (β3AR), two markers of beige adipocytes, in the interscapular BAT and inguinal white adipose tissue (WAT). Additionally, fish oil intake increased the elimination of urinary catecholamines and the noradrenaline (NA) turnover rate in interscapular BAT and inguinal WAT. Furthermore, the effects of fish oil on SNS-mediated energy expenditure were abolished in transient receptor potential vanilloid 1 (TRPV1) knockout mice. In conclusion, fish oil intake can induce UCP1 expression in classical brown and beige adipocytes via the SNS, thereby attenuating fat accumulation and ameliorating lipid metabolism. PMID:26673120

In vivo effects of CB2 receptor-selective cannabinoids on the vasculature of normal and arthritic rat knee joints

PubMed Central

McDougall, J J; Yu, V; Thomson, J

2007-01-01

Background and purpose: Cannabinoids (CBs) are known to be vasoactive and to regulate tissue inflammation. The present study examined the in vivo vasomotor effects of the CB2 receptor agonists JWH015 and JWH133 in rat knee joints. The effect of acute and chronic joint inflammation on CB2 receptor-mediated responses was also tested. Experimental approach: Blood flow was assessed in rat knee joints by laser Doppler imaging both before and following topical administration of CB2 receptor agonists. Vasoactivity was measured in normal, acute kaolin/carrageenan inflamed and Freund's complete adjuvant chronically inflamed knees. Key results: In normal animals, JWH015 and JWH133 caused a concentration-dependent increase in synovial blood flow which in the case of JWH133 was blocked by the selective CB2 receptor antagonist AM630 as well as the transient receptor potential vanilloid-1 (TRPV1) antagonist SB366791. The vasodilator effect of JWH133 was significantly attenuated in both acute and chronically inflamed knees. Given alone, AM630 had no effect on joint blood flow. Conclusion and implications: In normal joints, the cannabinomimetic JWH133 causes hyperaemia via a CB2 and TRPV1 receptor mechanism. During acute and chronic inflammation, however, this vasodilatatory response is significantly attenuated. PMID:17982474

Non-pharmacological treatment affects neuropeptide expression in neuropathic pain model.

PubMed

Santos, Fabio Martinez; Silva, Joyce Teixeira; Rocha, Igor Rafael Correia; Martins, Daniel Oliveira; Chacur, Marucia

2018-05-15

Chronic constriction injury (CCI) of the sciatic nerve elicits changes in neuropeptide expression on the dorsal root ganglia (DRG). The neural mobilization (NM) technique is a noninvasive method that has been proven clinically effective in reducing pain. The aim of this study was to analyze the expression of substance P, transient receptor potential vanilloid 1 (TRPV1) and opioid receptors in the DRG of rats with chronic constriction injury and to compare it to animals that received NM treatment. CCI was performed on adult male rats. Each animal was submitted to 10 sessions of neural mobilization every other day, starting 14 days after the CCI injury. At the end of the sessions, the DRG (L4-L6) were analyzed using Western blot assays for substance P, TRPV1 and opioid receptors (µ-opioid receptor, δ-opioid receptor and κ-opioid receptor). We observed a decreased substance P and TRPV1 expression (48% and 35%, respectively) and an important increase of µ-opioid receptor expression (200%) in the DRG after NM treatment compared to control animals. The data provide evidence that NM promotes substantial changes in neuropeptide expression in the DRG; these results may provide new options for treating neuropathic pain. Copyright © 2018 Elsevier B.V. All rights reserved.

Aronia melanocarpa (Black Chokeberry) Reduces Ethanol-Induced Gastric Damage via Regulation of HSP-70, NF-κB, and MCP-1 Signaling.

PubMed

Paulrayer, Antonisamy; Adithan, Aravinthan; Lee, Jeong Ho; Moon, Kwang Hyun; Kim, Dae Geun; Im, So Yeon; Kang, Chang-Won; Kim, Nam Soo; Kim, Jong-Hoon

2017-06-05

Aronia melanocarpa (Michx.) Ell. belongs to the Rosaceae family. The purpose of this study is to explore the gastroprotective effect of the Aronia melanocarpa hydro-alcoholic extract (AMHAE) against ethanol-induced gastric ulcer in a rat model. Different concentrations (50, 100, and 200 mg/kg) of AMHAE, or 30 mg/kg of omeprazole, significantly inhibited the gastric injury formation. The ethanol-induced ulcer group showed significant increases of malondialdehyde (MDA), myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, nuclear factor-kappaB p65 (NF-κB p65), and monocyte chemoattractant protein (MCP)-1, and decreased activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-px), and interleukin (IL)-4. However, AMHAE (200 mg/kg) pretreatment significantly reversed the altered pathophysiological levels of these biomolecules to near normal stages. The gastroprotective activity of AMHAE was abolished by pretreatment with l-NAME, naloxone, capsazepine, and indomethacin, demonstrating the participation of nitric oxide (NO), opioids, TRPV (vanilloid receptor-related transient receptor potential), and prostaglandins in AMHAE-assisted gastroprotection against ethanol-induced gastric injuries. This gastroprotective effect of AMHAE might be due to the downregulation of TNF-α-based NF-κB, MCP-1 signaling and strong antioxidant properties.

Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes

PubMed Central

Moreno, Claudia M.; O’Dwyer, Samantha; Woods, Sean

2017-01-01

TRPV4 (transient receptor potential vanilloid 4) channels are Ca2+-permeable channels that play a key role in regulating vascular tone. In arterial myocytes, opening of TRPV4 channels creates local increases in Ca2+ influx, detectable optically as “TRPV4 sparklets.” TRPV4 sparklet activity can be enhanced by the action of the vasoconstrictor angiotensin II (AngII). This modulation depends on the activation of subcellular signaling domains that comprise protein kinase C α (PKCα) bound to the anchoring protein AKAP150. Here, we used super-resolution nanoscopy, patch-clamp electrophysiology, Ca2+ imaging, and mathematical modeling approaches to test the hypothesis that AKAP150-dependent modulation of TRPV4 channels is critically dependent on the distance between these two proteins in the sarcolemma of arterial myocytes. Our data show that the distance between AKAP150 and TRPV4 channel clusters varies with sex and arterial bed. Consistent with our hypothesis, we further find that basal and AngII-induced TRPV4 channel activity decays exponentially as the distance between TRPV4 and AKAP150 increases. Our data suggest a maximum radius of action of ∼200 nm for local modulation of TRPV4 channels by AKAP150-associated PKCα. PMID:28507079

Contributions of different modes of TRPV1 activation to TRPV1 antagonist-induced hyperthermia.

PubMed

Garami, Andras; Shimansky, Yury P; Pakai, Eszter; Oliveira, Daniela L; Gavva, Narender R; Romanovsky, Andrej A

2010-01-27

Transient receptor potential vanilloid-1 (TRPV1) antagonists are widely viewed as next-generation pain therapeutics. However, these compounds cause hyperthermia, a serious side effect. TRPV1 antagonists differentially block three modes of TRPV1 activation: by heat, protons, and chemical ligands (e.g., capsaicin). We asked what combination of potencies in these three modes of TRPV1 activation corresponds to the lowest potency of a TRPV1 antagonist to cause hyperthermia. We studied hyperthermic responses of rats, mice, and guinea pigs to eight TRPV1 antagonists with different pharmacological profiles and used mathematical modeling to find a relative contribution of the blockade of each activation mode to the development of hyperthermia. We found that the hyperthermic effect has the highest sensitivity to the extent of TRPV1 blockade in the proton mode (0.43 to 0.65) with no to moderate sensitivity in the capsaicin mode (-0.01 to 0.34) and no sensitivity in the heat mode (0.00 to 0.01). We conclude that hyperthermia-free TRPV1 antagonists do not block TRPV1 activation by protons, even if they are potent blockers of the heat mode, and that decreasing the potency to block the capsaicin mode may further decrease the potency to cause hyperthermia.

Contributions of different modes of TRPV1 activation to TRPV1 antagonist-induced hyperthermia

PubMed Central

Garami, Andras; Shimansky, Yury P.; Pakai, Eszter; Oliveira, Daniela L.; Gavva, Narender R.; Romanovsky, Andrej A.

2010-01-01

Transient receptor potential vanilloid-1 (TRPV1) antagonists are widely viewed as next-generation pain therapeutics. However, these compounds cause hyperthermia, a serious side effect. TRPV1 antagonists differentially block three modes of TRPV1 activation: by heat, protons, and chemical ligands (e.g., capsaicin). We asked what combination of potencies in these three modes of TRPV1 activation corresponds to the lowest potency of a TRPV1 antagonist to cause hyperthermia. We studied hyperthermic responses of rats, mice, and guinea pigs to eight TRPV1 antagonists with different pharmacological profiles and used mathematical modeling to find a relative contribution of the blockade of each activation mode to the development of hyperthermia. We have found that the hyperthermic effect has the highest sensitivity to the extent of TRPV1 blockade in the proton mode (0.43 to 0.65) with no to moderate sensitivity in the capsaicin mode (-0.01 to 0.34) and no sensitivity in the heat mode (0.00 to 0.01). We conclude that hyperthermia-free TRPV1 antagonists do not block TRPV1 activation by protons, even if they are potent blockers of the heat mode, and that decreasing the potency to block the capsaicin mode may further decrease the potency to cause hyperthermia. PMID:20107070

Expressions of TRPVs in the cholesteatoma epithelium.

PubMed

Do, Ba Hung; Koizumi, Hiroki; Ohbuchi, Toyoaki; Kawaguchi, Rintaro; Suzuki, Hideaki

2017-10-01

We have recently proposed a hypothesis that acid leakage through the cholesteatoma epithelium mediates bone resorption in middle ear cholesteatoma. In the present study, we investigated the expressions of transient receptor potential vanilloid (TRPV) channels, which have been shown to play roles in the regulation of epidermal barrier function, in the cholesteatoma epithelium in comparison with the normal skin. Cholesteatoma epithelium and postauricular skin were collected from 17 patients with primary acquired middle ear cholesteatoma who underwent tympanomastoidectomy. Expressions of TRPV1, TRPV3, TRPV4, and TRPV6 were explored by fluorescence immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). TRPV1, TRPV3, TRPV4, and TRPV6 mRNAs were all detected by qRT-PCR both in the skin and cholesteatoma tissue. Immunohistochemical staining showed that TRPV1 and TRPV3 were positive in the viable cell layers of the epidermis of the skin, and only TRPV3 was positive in those of the cholesteatoma epithelium. The immunoreactivity for TRPV3 was significantly weaker in cholesteatoma than in the skin. The lower expression of TRPV3 in cholesteatoma may be one of the mechanisms underlying the increased permeability of this tissue. On the other hand, TRPV1, TRPV4, and TRPV6 are unlikely to be involved in the regulation of epithelial permeability in cholesteatoma.

Involvement of TRPV2 activation in intestinal movement through nitric oxide production in mice.

PubMed

Mihara, Hiroshi; Boudaka, Ammar; Shibasaki, Koji; Yamanaka, Akihiro; Sugiyama, Toshiro; Tominaga, Makoto

2010-12-08

Transient receptor potential channel vanilloid 2 (TRPV2) can detect various stimuli such as temperature (>52 °C), stretch, and chemicals, including 2-aminoethoxydiphenyl borate, probenecid, and lysophospholipids. Although expressed in many tissues, including sensory and motor neurons, TRPV2 expression and function in the gastrointestinal tract is poorly understood. Here, we show TRPV2 expression in the murine intestine and its involvement in intestinal function. Almost all mouse intestinal intrinsic sensory and inhibitory motor neurons, both cell bodies and nerve fibers, showed TRPV2 immunoreactivity. Several known TRPV2 activators increased cytosolic Ca²+ concentrations and evoked TRPV2-like current responses in dissociated myenteric neurons. Interestingly, mechanical stimuli activated inward currents in a strength-dependent manner, which were inhibited by a TRPV2 inhibitor tranilast. TRPV2 activation in isolated intestine inhibited spontaneous circular muscle contraction, which did not occur in the presence of the TRPV2 antagonist, tetrodotoxin or nitro oxide (NO) synthase pathway inhibitors. Also, increased intestinal NO production was observed in response to a TRPV2 agonist, and gastrointestinal transit in vivo was accelerated by TRPV2 agonists or an NO donor. In conclusion, TRPV2 may contribute to intestinal motility through NO production, and TRPV2 is a promising target for controlling intestinal movement.

Activation of TRPV2 negatively regulates the differentiation of mouse brown adipocytes.

PubMed

Sun, Wuping; Uchida, Kunitoshi; Takahashi, Nobuyuki; Iwata, Yuko; Wakabayashi, Shigeo; Goto, Tsuyoshi; Kawada, Teruo; Tominaga, Makoto

2016-09-01

Transient receptor potential vanilloid 2 (TRPV2) acts as a Ca(2+)-permeable non-selective cation channel that has been reported to be sensitive to temperature, mechanical force, and some chemicals. We recently showed that TRPV2 is critical for maintenance of the thermogenic function of brown adipose tissue in mice. However, the involvement of TRPV2 in the differentiation of brown adipocytes remains unexplored. We found that the expression of TRPV2 was dramatically increased during the differentiation of brown adipocytes. Non-selective TRPV2 agonists (2-aminoethoxydiphenyl borate and lysophosphatidylcholine) inhibited the differentiation of brown adipocytes in a dose-dependent manner during the early stage of differentiation of brown adipocytes. The inhibition was rescued by a TRPV2-selective antagonist, SKF96365 (SKF). Mechanical force, which activates TRPV2, also inhibited the differentiation of brown adipocytes in a strength-dependent manner, and the effect was reversed by SKF. In addition, the inhibition of adipocyte differentiation by either TRPV2 ligand or mechanical stimulation was significantly smaller in the cells from TRPV2KO mice. Moreover, calcineurin inhibitors, cyclosporine A and FK506, partially reversed TRPV2 activation-induced inhibition of brown adipocyte differentiation. Thus, we conclude that TRPV2 might be involved in the modulation of brown adipocyte differentiation partially via a calcineurin pathway.

Intrathecal [6]-gingerol administration alleviates peripherally induced neuropathic pain in male Sprague-Dawley rats.

PubMed

Gauthier, Marie-Lou; Beaudry, Francis; Vachon, Pascal

2013-08-01

[6]-Gingerol, a structural analog of capsaicin, is an agonist of the transient receptor potential vanilloid 1 channel, which is known to have therapeutic properties for the treatment of pain and inflammation. The main objective of this study was to determine the central effect of [6]-gingerol on neuropathic pain when injected intrathecally at the level of the lumbar spinal cord. [6]-Gingerol distribution was evaluated following a 40 mg/kg intraperitoneal injection, and the brain-to-plasma and spinal cord-to-plasma ratios (0.73 and 1.7, respectively) suggest that [6]-gingerol penetrates well the central nervous system of rats. Induction of pain was performed using the sciatic nerve ligation model on rats, and a 10-µg intrathecal injections of [6]-gingerol was performed to evaluate its central effect. The results suggest a significant decrease of secondary mechanical allodynia after 30 min, 2 h and 4 h (p < 0.05, p < 0.01 and p < 0.001) and thermal hyperalgesia after 30 min, 2 h and 4 h (p < 0.05, p < 0.01 and p < 0.01). These promising results illustrate that [6]-gingerol could alleviate neuropathic pain by acting centrally at the level of the spinal cord. Copyright © 2012 John Wiley & Sons, Ltd.

A painful link between the TRPV1 channel and lysophosphatidic acid.

PubMed

Morales-Lázaro, Sara L; Rosenbaum, Tamara

2015-03-15

The Transient Receptor Potential Vanilloid 1 (TRPV1) ion channel is expressed mainly by sensory neurons that detect noxious stimuli from the environment such as high temperatures and pungent compounds (such as allicin and capsaicin) and has been extensively linked to painful and inflammatory processes. This extraordinary protein also responds to endogenous stimuli among which we find molecules of a lipidic nature. We recently described that lysophosphatidic acid (LPA), a bioactive lysophospholipid linked to the generation and maintenance of pain, can directly activate TRPV1 and produce pain by binding to the channels' C-terminal region, specifically to residue K710. In an effort to further understand how activation of TRPV1 is achieved by this negatively-charged lipid, we used several synthetic and naturally-occurring lipids to determine the structural requirements that need to be met by these charged lipids in order to produce the activation of TRPV1. In this review, we detail the findings obtained by other research groups and our own on the field of TRPV1-regulation by negatively-charged lipids and discuss the possible therapeutic relevance of these findings on the basis of the role of TRPV1 in pathophysiological processes. Copyright © 2014 Elsevier Inc. All rights reserved.

Aronia melanocarpa (Black Chokeberry) Reduces Ethanol-Induced Gastric Damage via Regulation of HSP-70, NF-κB, and MCP-1 Signaling

PubMed Central

Paulrayer, Antonisamy; Adithan, Aravinthan; Lee, Jeong Ho; Moon, Kwang Hyun; Kim, Dae Geun; Im, So Yeon; Kang, Chang-Won; Kim, Nam Soo; Kim, Jong-Hoon

2017-01-01

Aronia melanocarpa (Michx.) Ell. belongs to the Rosaceae family. The purpose of this study is to explore the gastroprotective effect of the Aronia melanocarpa hydro-alcoholic extract (AMHAE) against ethanol-induced gastric ulcer in a rat model. Different concentrations (50, 100, and 200 mg/kg) of AMHAE, or 30 mg/kg of omeprazole, significantly inhibited the gastric injury formation. The ethanol-induced ulcer group showed significant increases of malondialdehyde (MDA), myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, nuclear factor-kappaB p65 (NF-κB p65), and monocyte chemoattractant protein (MCP)-1, and decreased activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-px), and interleukin (IL)-4. However, AMHAE (200 mg/kg) pretreatment significantly reversed the altered pathophysiological levels of these biomolecules to near normal stages. The gastroprotective activity of AMHAE was abolished by pretreatment with l-NAME, naloxone, capsazepine, and indomethacin, demonstrating the participation of nitric oxide (NO), opioids, TRPV (vanilloid receptor-related transient receptor potential), and prostaglandins in AMHAE-assisted gastroprotection against ethanol-induced gastric injuries. This gastroprotective effect of AMHAE might be due to the downregulation of TNF-α-based NF-κB, MCP-1 signaling and strong antioxidant properties. PMID:28587230

Interaction of capsaicinoids with cell membrane models does not correlate with pungency of peppers

NASA Astrophysics Data System (ADS)

Geraldo, Vananélia P. N.; Ziglio, Analine C.; Gonçalves, Débora; Oliveira, Osvaldo N.

2017-04-01

Mixed monolayers were prepared using phospholipids in order to mimic cell membranes and fractions of capsaicinoids (extracted from Malagueta, Caps-M, and Bhut Jolokia, Caps-B, peppers). According to their surface-pressure isotherms and polarization-modulated infrared reflection absorption spectra (PM-IRRAS), weak molecular-level interactions were observed between Caps and phospholipids. Both Caps-M and Caps-B penetrated into the alkyl tail region of the monolayer, interacted with the phosphate group of the phospholipids and affected hydration of their Cdbnd O groups. Since the physiological activity of Caps is not governed solely by interaction with cell membranes, it should require participation of a neuronal membrane receptor, e.g. vanilloid receptor (TRPV1).

Molecular targets for cannabidiol and its synthetic analogues: effect on vanilloid VR1 receptors and on the cellular uptake and enzymatic hydrolysis of anandamide

PubMed Central

Bisogno, Tiziana; Hanuš, Lumír; De Petrocellis, Luciano; Tchilibon, Susanna; Ponde, Datta E; Brandi, Ines; Moriello, Aniello Schiano; Davis, John B; Mechoulam, Raphael; Di Marzo, Vincenzo

2001-01-01

(−)-Cannabidiol (CBD) is a non-psychotropic component of Cannabis with possible therapeutic use as an anti-inflammatory drug. Little is known on the possible molecular targets of this compound. We investigated whether CBD and some of its derivatives interact with vanilloid receptor type 1 (VR1), the receptor for capsaicin, or with proteins that inactivate the endogenous cannabinoid, anandamide (AEA).CBD and its enantiomer, (+)-CBD, together with seven analogues, obtained by exchanging the C-7 methyl group of CBD with a hydroxy-methyl or a carboxyl function and/or the C-5′ pentyl group with a di-methyl-heptyl (DMH) group, were tested on: (a) VR1-mediated increase in cytosolic Ca2+ concentrations in cells over-expressing human VR1; (b) [14C]-AEA uptake by RBL-2H3 cells, which is facilitated by a selective membrane transporter; and (c) [14C]-AEA hydrolysis by rat brain membranes, which is catalysed by the fatty acid amide hydrolase.Both CBD and (+)-CBD, but not the other analogues, stimulated VR1 with EC50=3.2 – 3.5 μM, and with a maximal effect similar in efficacy to that of capsaicin, i.e. 67 – 70% of the effect obtained with ionomycin (4 μM). CBD (10 μM) desensitized VR1 to the action of capsaicin. The effects of maximal doses of the two compounds were not additive.(+)-5′-DMH-CBD and (+)-7-hydroxy-5′-DMH-CBD inhibited [14C]-AEA uptake (IC50=10.0 and 7.0 μM); the (−)-enantiomers were slightly less active (IC50=14.0 and 12.5 μM). CBD and (+)-CBD were also active (IC50=22.0 and 17.0 μM).CBD (IC50=27.5 μM), (+)-CBD (IC50=63.5 μM) and (−)-7-hydroxy-CBD (IC50=34 μM), but not the other analogues (IC50>100 μM), weakly inhibited [14C]-AEA hydrolysis.Only the (+)-isomers exhibited high affinity for CB1 and/or CB2 cannabinoid receptors.These findings suggest that VR1 receptors, or increased levels of endogenous AEA, might mediate some of the pharmacological effects of CBD and its analogues. In view of the facile high yield synthesis, and the weak affinity for CB1 and CB2 receptors, (−)-5′-DMH-CBD represents a valuable candidate for further investigation as inhibitor of AEA uptake and a possible new therapeutic agent. PMID:11606325

Multiple Forms of Endocannabinoid and Endovanilloid Signaling Regulate the Tonic Control of GABA Release

PubMed Central

Lee, Sang-Hun; Ledri, Marco; Tóth, Blanka; Marchionni, Ivan; Henstridge, Christopher M.; Dudok, Barna; Kenesei, Kata; Barna, László; Szabó, Szilárd I.; Renkecz, Tibor; Oberoi, Michelle; Watanabe, Masahiko; Limoli, Charles L.; Horvai, George; Soltesz, Ivan

2015-01-01

Persistent CB1 cannabinoid receptor activity limits neurotransmitter release at various synapses throughout the brain. However, it is not fully understood how constitutively active CB1 receptors, tonic endocannabinoid signaling, and its regulation by multiple serine hydrolases contribute to the synapse-specific calibration of neurotransmitter release probability. To address this question at perisomatic and dendritic GABAergic synapses in the mouse hippocampus, we used a combination of paired whole-cell patch-clamp recording, liquid chromatography/tandem mass spectrometry, stochastic optical reconstruction microscopy super-resolution imaging, and immunogold electron microscopy. Unexpectedly, application of the CB1 antagonist and inverse agonist AM251 [N-1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide], but not the neutral antagonist NESS0327 [8-chloro-1-(2,4-dichlorophenyl)-N-piperidin-1-yl-5,6-dihydro-4H-benzo[2,3]cyclohepta[2,4-b]pyrazole-3-carboxamine], significantly increased synaptic transmission between CB1-positive perisomatic interneurons and CA1 pyramidal neurons. JZL184 (4-nitrophenyl 4-[bis(1,3-benzodioxol-5-yl)(hydroxy)methyl]piperidine-1-carboxylate), a selective inhibitor of monoacylglycerol lipase (MGL), the presynaptic degrading enzyme of the endocannabinoid 2-arachidonoylglycerol (2-AG), elicited a robust increase in 2-AG levels and concomitantly decreased GABAergic transmission. In contrast, inhibition of fatty acid amide hydrolase (FAAH) by PF3845 (N-pyridin-3-yl-4-[[3-[5-(trifluoromethyl)pyridin-2-yl]oxyphenyl]methyl]piperidine-1-carboxamide) elevated endocannabinoid/endovanilloid anandamide levels but did not change GABAergic synaptic activity. However, FAAH inhibitors attenuated tonic 2-AG increase and also decreased its synaptic effects. This antagonistic interaction required the activation of the transient receptor potential vanilloid receptor TRPV1, which was concentrated on postsynaptic intracellular membrane cisternae at perisomatic GABAergic symmetrical synapses. Interestingly, neither AM251, JZL184, nor PF3845 affected CB1-positive dendritic interneuron synapses. Together, these findings are consistent with the possibility that constitutively active CB1 receptors substantially influence perisomatic GABA release probability and indicate that the synaptic effects of tonic 2-AG release are tightly controlled by presynaptic MGL activity and also by postsynaptic endovanilloid signaling and FAAH activity. SIGNIFICANCE STATEMENT Tonic cannabinoid signaling plays a critical role in the regulation of synaptic transmission. However, the mechanistic details of how persistent CB1 cannabinoid receptor activity inhibits neurotransmitter release have remained elusive. Therefore, electrophysiological recordings, lipid measurements, and super-resolution imaging were combined to elucidate those signaling molecules and mechanisms that underlie tonic cannabinoid signaling. The findings indicate that constitutive CB1 activity has pivotal function in the tonic control of hippocampal GABA release. Moreover, the endocannabinoid 2-arachidonoylglycerol (2-AG) is continuously generated postsynaptically, but its synaptic effect is regulated strictly by presynaptic monoacylglycerol lipase activity. Finally, anandamide signaling antagonizes tonic 2-AG signaling via activation of postsynaptic transient receptor potential vanilloid TRPV1 receptors. This unexpected mechanistic diversity may be necessary to fine-tune GABA release probability under various physiological and pathophysiological conditions. PMID:26157003

Sumatriptan Inhibits TRPV1 Channels in Trigeminal Neurons

PubMed Central

Evans, M. Steven; Cheng, Xiangying; Jeffry, Joseph A.; Disney, Kimberly E.; Premkumar, Louis S.

2011-01-01

Objective To understand a possible role for transient potential receptor vanilloid 1 (TRPV1) ion channels in sumatriptan relief of pain mediated by trigeminal nociceptors. Background TRPV1 channels are expressed in small nociceptive sensory neurons. In dorsal root ganglia (DRG), TRPV1-containing nociceptors mediate certain types of inflammatory pain. Neurogenic inflammation of cerebral dura and blood vessels in the trigeminal nociceptive system is thought to be important in migraine pain, but the ion channels important in transducing migraine pain are not known. Sumatriptan is an agent effective in treatment of migraine and cluster headache. We hypothesized that sumatriptan might modulate activity of TRPV1 channels found in the trigeminal nociceptive system. Methods We used immunohistochemistry to detect the presence of TRPV1 channel protein, whole cell recording in acutely dissociated trigeminal ganglia (TG) to detect functionality of TRPV1 channels, and whole cell recording in trigeminal nucleus caudalis (TNC) to detect effects on release of neurotransmitters from trigeminal neurons onto second order sensory neurons. Effects specifically on TG neurons that project to cerebral dura were assessed by labeling dural nociceptors with DiI. Results Immunohistochemistry demonstrated that TRPV1 channels are present in cerebral dura, trigeminal ganglion, and in the trigeminal nucleus caudalis. Capsaicin, a TRPV1 agonist, produced depolarization and repetitive action potential firing in current clamp recordings and large inward currents in voltage clamp recordings from acutely dissociated TG neurons, demonstrating that TRPV1 channels are functional in trigeminal neurons. Capsaicin increased spontaneous excitatory postsynaptic currents (sEPSCs) in neurons of layer II in TNC slices, showing that these channels have a physiological effect on central synaptic transmission. Sumatriptan (10 μM), a selective anti-migraine drug inhibited TRPV1-mediated inward currents in TG. and capsaicin-elicited sEPSCs in TNC slices. The same effects of capsaicin and sumatriptan were found in acutely dissociated DiI-labeled TG neurons innervating cerebral dura. Conclusion Our results build on previous work indicating that TRPV1 channels in trigeminal nociceptors play a role in craniofacial pain. Our findings that TRPV1 is inhibited by the specific antimigraine drug sumatriptan, and that TRPV1 channels are functional in neurons projecting to cerebral dura suggests a specific role for these channels in migraine or cluster headache. PMID:22289052

In vivo potency of different ligands on voltage-gated sodium channels.

PubMed

Safrany-Fark, Arpad; Petrovszki, Zita; Kekesi, Gabriella; Liszli, Peter; Benedek, Gyorgy; Keresztes, Csilla; Horvath, Gyongyi

2015-09-05

The Ranvier nodes of thick myelinated nerve fibers contain almost exclusively voltage-gated sodium channels (Navs), while the unmyelinated fibers have several receptors (e.g., cannabinoid, transient receptor potential vanilloid receptor 1), too. Therefore, a nerve which contains only motor fibers can be an appropriate in vivo model for selective influence of Navs. The goals were to evaluate the potency of local anesthetic drugs on such a nerve in vivo; furthermore, to investigate the effects of ligands with different structures (arachidonic acid, anandamide, capsaicin and nisoxetine) that were proved to inhibit Navs in vitro with antinociceptive properties. The marginal mandibular branch of the facial nerve was explored in anesthetized Wistar rats; after its stimulation, the electrical activity of the vibrissae muscles was registered following the perineural injection of different drugs. Lidocaine, bupivacaine and ropivacaine evoked dose-dependent decrease in electromyographic activity, i.e., lidocaine had lower potency than bupivacaine or ropivacaine. QX-314 did not cause any effect by itself, but its co-application with lidocaine produced a prolonged inhibition. Nisoxetine had a very low potency. While anandamide and capsaicin in high doses caused about 50% decrease in the amplitude of action potential, arachidonic acid did not influence the responses. We proved that the classical local anesthetics have high potency on motor nerves, suggesting that this method might be a reliable model for selective targeting of Navs in vivo circumstances. It is proposed that the effects of these endogenous lipids and capsaicin on sensory fibers are not primarily mediated by Navs. Copyright © 2015 Elsevier B.V. All rights reserved.

Bradykinin Induces TRPV1 Exocytotic Recruitment in Peptidergic Nociceptors

PubMed Central

Mathivanan, Sakthikumar; Devesa, Isabel; Changeux, Jean-Pierre; Ferrer-Montiel, Antonio

2016-01-01

Transient receptor potential vanilloid I (TRPV1) sensitization in peripheral nociceptors is a prominent phenomenon that occurs in inflammatory pain conditions. Pro-algesic agents can potentiate TRPV1 activity in nociceptors through both stimulation of its channel gating and mobilization of channels to the neuronal surface in a context dependent manner. A recent study reported that ATP-induced TRPV1 sensitization in peptidergic nociceptors involves the exocytotic release of channels trafficked by large dense core vesicles (LDCVs) that cargo alpha-calcitonin gene related peptide alpha (αCGRP). We hypothesized that, similar to ATP, bradykinin may also use different mechanisms to sensitize TRPV1 channels in peptidergic and non-peptidergic nociceptors. We found that bradykinin notably enhances the excitability of peptidergic nociceptors, and sensitizes TRPV1, primarily through the bradykinin receptor 2 pathway. Notably, bradykinin sensitization of TRPV1 in peptidergic nociceptors was significantly blocked by inhibiting Ca2+-dependent neuronal exocytosis. In addition, silencing αCGRP gene expression, but not substance P, drastically reduced bradykinin-induced TRPV1 sensitization in peptidergic nociceptors. Taken together, these findings indicate that bradykinin-induced sensitization of TRPV1 in peptidergic nociceptors is partially mediated by the exocytotic mobilization of new channels trafficked by αCGRP-loaded LDCVs to the neuronal membrane. Our findings further imply a central role of αCGRP peptidergic nociceptors in peripheral algesic sensitization, and substantiate that inhibition of LDCVs exocytosis is a valuable therapeutic strategy to treat pain, as it concurrently reduces the release of pro-inflammatory peptides and the membrane recruitment of thermoTRP channels. PMID:27445816

Formation of a physiological complex between TRPV2 and RGA protein promotes cell surface expression of TRPV2.

PubMed

Stokes, Alexander J; Wakano, Clay; Del Carmen, Kimberly A; Koblan-Huberson, Murielle; Turner, Helen

2005-03-01

The transient receptor potential, sub-family Vanilloid (TRPV)(2) cation channel is activated in response to extreme temperature elevations in sensory neurons. However, TRPV2 is widely expressed in tissues with no sensory function, including cells of the immune system. Regulation of GRC, the murine homolog of TRPV2 has been studied in insulinoma cells and myocytes. GRC is activated in response to certain growth factors and neuropeptides, via a mechanism that involves regulated access of the channel to the plasma membrane. This is likely to be an important primary control mechanism for TRPV2 outside the CNS. Here, we report that a regulated trafficking step controls the access of TRPV2 to the cell surface in mast cells. In mast cells, elevations in cytosolic cAMP are sufficient to drive plasma membrane localization of TRPV2. We have previously proposed that the recombinase gene activator protein (RGA), a four-transmembrane domain, intracellular protein, associates with TRPV2 during the biosynthesis and early trafficking of the channel. We use a polyclonal antibody to RGA to confirm the formation of a physiological complex between RGA and TRPV2. Finally, we show that over-expression of the RGA protein potentiates the basal surface localization of TRPV2. We propose that trafficking and activation mechanisms intersect for TRPV2, and that cAMP mobilizing stimuli may regulate TRPV2 localization in non-sensory cells. RGA participates in the control of TRPV2 surface levels, and co-expression of RGA may be a key component of experimental systems that seek to study TRPV2 physiology.

Differential regulation of ASICs and TRPV1 by zinc in rat bronchopulmonary sensory neurons.

PubMed

Vysotskaya, Zhanna V; Moss, Charles R; Gu, Qihai

2014-12-01

Zinc has been known to act as a signaling molecule that regulates a variety of neuronal functions. In this study, we aimed to study the effect of zinc on two populations of acid-sensitive ion channels, acid-sensing ion channels (ASICs), and transient receptor potential vanilloid receptor-1 (TRPV1), in vagal bronchopulmonary sensory neurons. Rat vagal sensory neurons innervating lungs and airways were retrogradely labeled with a fluorescent tracer. Whole-cell perforated patch-clamp recordings were carried out in primarily cultured bronchopulmonary sensory neurons. The acid-evoked ASIC and TRPV1 currents were measured and compared between before and after the zinc pretreatment. ASIC currents were induced by a pH drop from 7.4 to 6.8 or 6.5 in the presence of capsazepine (10 µM), a specific TRPV1 antagonist. Pretreatment with zinc (50 or 300 µM, 2 min) displayed different effects on the two distinct phenotypes of ASIC currents: a marked potentiation on ASIC channels with fast kinetics of activation and inactivation or no significant effect on ASIC currents with slow activation and inactivation. On the other hand, pretreatment with zinc significantly inhibited the acid (pH 5.5 or 5.3)-induced TRPV1 currents. The inhibition was abolished by intracellular chelation of zinc by TPEN (25 µM), indicating that intracellular accumulation of zinc was likely required for its inhibitory effect on TRPV1 channels. Our study showed that zinc differentially regulates the activities of ASICs and TRPV1 channels in rat vagal bronchopulmonary sensory neurons.

Mechanism of Activation of Enteric Nociceptive Neurons via Interaction of TLR4 and TRPV1 Receptors.

PubMed

Filippova, L V; Fedorova, A V; Nozdrachev, A D

2018-03-01

Evidence obtained by immunohistochemical double labeling and confocal laser scanning microscopy suggests that capsaicin, a ligand of the TRPV1 nociceptive vanilloid receptor, increases the number of TLR4-positive neurons in the rat colon myenteric plexus. In colitis caused by trinitrobenzene sulfonate, an increase in TRPV1 expression was more significant in both plexuses. Specific inhibitor of the TLR4 (C34) pattern-recognition receptor reduces TRPV1 expression in enteric neurons of both intact rats and rats with induced acute colitis. Thus, stimulation of nociceptive neurons by means of direct activation of their receptors of innate immunity (TLR4) is one of the possible mechanisms underlying the visceral pain in bacterial invasion and inflammatory bowel diseases.

[Vesical urothelium and new concepts].

PubMed

Giannantoni, Antonella; Proietti, Silvia; Giovannozzi, Silvia; Porena, Massimo

2012-01-01

Vesical urothelium was long considered to simply be a protection barrier, which passively separates the urinary content from the underlying smooth muscle and the blood stream. Recent observations, though, have pointed out that vesical urothelium cells have clear active and sensory functions, in response to various physical and chemical stimuli. Among these characteristics are the expression of several neurotransmitters and receptors: Acetylcholine, Nitric Oxide, VIP, CGRP, NKA, SP and cholinergic, vanilloid, purinergic, and tachykinin receptors. Urothelium-produced neurotransmitters are likely supposed to act through a receptor stimulation of the afferent nerve fibers within the sub-urothelial spaces. Sub-urothelial myofibroblasts are considered to play a mediation role between urothelium-produced neurotransmitters and the underlying receptors. According to these observations, a pharmacologic modulation, directly affecting the urothelium, can be hypothesized.

Calcium influx through the TRPV1 channel of endothelial cells (ECs) correlates with a stronger adhesion between monocytes and ECs.

PubMed

Himi, N; Hamaguchi, A; Hashimoto, K; Koga, T; Narita, K; Miyamoto, O

2012-01-01

Atherosclerosis is thought to be initiated by the transendothelial migration of monocytes. In the early stage of this process, the adhesion of monocytes to endothelial cells is supported by an increase in the intracellular concentration of calcium ion ([Ca(2+)]i) in endothelial cells. However, the main source of Ca(2+) has been unclear. In this study, the changes in ionic transmittance and [Ca(2+)]i due to the adhesion of monocytes were continuously measured by an electrophysiological technique and fluorescent imaging. Especially, we focused on transient receptor potential vanilloid channel 1 (TRPV1) as a Ca(2+) channel that could influence the adhesion of monocytes. Whole-cell current was continuously recorded in human umbilical vein endothelial cells (HUVECs) by a patch electrode. The adhesion of monocytes (THP-1) induced a transient inward current in HUVECs, as well as an elevation of [Ca(2+)]i. This inward element was abolished by the application of 100 nM SB366,791, a selective antagonist of TRPV1 channel. Furthermore, SB366,791 significantly decreased the number of THP-1 cells that adhered to HUVECs (control: 231 ± 38, SB366,791: 96 ± 16 cells/mm2). These results suggest that an inward calcium current via the TRPV1 channels of endothelial cells correlates with a stronger adhesion between monocytes and endothelial cells.

TRPV1 channels in the nucleus of the solitary tract mediate thermal prolongation of the LCR in decerebrate piglets

PubMed Central

Xia, Luxi; Bartlett, Donald; Leiter, J.C.

2011-01-01

Elevating body temperature or just the temperature of the dorsal medulla by approximately 2 °C prolongs the laryngeal chemoreflex (LCR) in decerebrate neonatal piglets. We tested the hypothesis that transient receptor potential vanilloid 1 (TRPV1) receptors in the nucleus of the solitary tract (NTS) mediate thermal prolongation of the LCR. We studied the effect of a selective TRPV1 receptor antagonist on thermal prolongation of the LCR, and we tested the effect of a TRPV1 agonist on the duration of the LCR under normothermic conditions. We studied 37 decerebrate neonatal piglets between the ages of post-natal days 4 and 7. The TRPV1 receptor antagonist, 5−iodoresiniferatoxin (65 microM/L in 100 nL), blocked thermal prolongation of the LCR when injected bilaterally into the region of the NTS. The TRPV1 agonist, resiniferatoxin (0.65-1.0 mM/L in 100 nL), prolonged the LCR after bilateral injection into the NTS even when the body temperature of each piglet was normal. The effect of the TRPV1 agonists could be blocked by treatment with the GABAA receptor antagonist, bicuculline, whether given intravenously (0.3 mg/kg) or focally injected bilaterally into the NTS (10 mM in 100nL). We conclude that TRPV1 receptors in the NTS mediate thermal prolongation of the LCR. PMID:21276877

Enhancement of immune cytokines and splenic CD4+ T cells by electroacupuncture at ST36 acupoint of SD rats.

PubMed

Chen, Longyun; Xu, Anli; Yin, Nina; Zhao, Min; Wang, Zhigang; Chen, Tao; Gao, Yisheng; Chen, Zebin

2017-01-01

Electroacupuncture at the ST36 acupoint can enhance the body's immune function. However, the mechanism for this enhancement has not been fully described. Our study was designed to investigate the effect of electroacupuncture on the immune function of Sprague-Dawley (SD) rats. The rats were randomly divided into three groups: a control group, a non-acupoint group (abdominal muscle acupuntured) and a ST36 acupoint group. Our results showed that successive electroacupuncture at the ST36 acupoint for 3 d significantly enhanced the interferon-γ (IFN-γ) level in the serum of SD rats. The results also showed that the serum and extracts from spleen cells of the ST36 acupoint group contained higher levels of interleukin (IL)-2 and IL-17 compared to those of the other two groups. Immunohistochemical analysis showed that electroacupuncture applied to the ST36 acupoint enhanced the expression level of CD4 in spleen cells. Furthermore, it was observed that CD4 co-localized with transient receptor potential vanilloid (TRPV) channels at the membrane of splenic CD4+ T cells and the expression level of CD4 was related to TRPV channels in the electroacupuncture treatment. These observations indicated that electroacupuncture stimulation at the ST36 acupoint enhanced the level of immune cytokines and splenic CD4+ T cells through TRPV channels in this system.

Enhancement of immune cytokines and splenic CD4+ T cells by electroacupuncture at ST36 acupoint of SD rats

PubMed Central

Yin, Nina; Zhao, Min; Wang, Zhigang; Chen, Tao; Gao, Yisheng; Chen, Zebin

2017-01-01

Electroacupuncture at the ST36 acupoint can enhance the body’s immune function. However, the mechanism for this enhancement has not been fully described. Our study was designed to investigate the effect of electroacupuncture on the immune function of Sprague-Dawley (SD) rats. The rats were randomly divided into three groups: a control group, a non-acupoint group (abdominal muscle acupuntured) and a ST36 acupoint group. Our results showed that successive electroacupuncture at the ST36 acupoint for 3 d significantly enhanced the interferon-γ (IFN-γ) level in the serum of SD rats. The results also showed that the serum and extracts from spleen cells of the ST36 acupoint group contained higher levels of interleukin (IL)-2 and IL-17 compared to those of the other two groups. Immunohistochemical analysis showed that electroacupuncture applied to the ST36 acupoint enhanced the expression level of CD4 in spleen cells. Furthermore, it was observed that CD4 co-localized with transient receptor potential vanilloid (TRPV) channels at the membrane of splenic CD4+ T cells and the expression level of CD4 was related to TRPV channels in the electroacupuncture treatment. These observations indicated that electroacupuncture stimulation at the ST36 acupoint enhanced the level of immune cytokines and splenic CD4+ T cells through TRPV channels in this system. PMID:28406959

TRPV4 inhibition counteracts edema and inflammation and improves pulmonary function and oxygen saturation in chemically induced acute lung injury

PubMed Central

Balakrishna, Shrilatha; Song, Weifeng; Achanta, Satyanarayana; Doran, Stephen F.; Liu, Boyi; Kaelberer, Melanie M.; Yu, Zhihong; Sui, Aiwei; Cheung, Mui; Leishman, Emma; Eidam, Hilary S.; Ye, Guosen; Willette, Robert N.; Thorneloe, Kevin S.; Bradshaw, Heather B.; Matalon, Sadis

2014-01-01

The treatment of acute lung injury caused by exposure to reactive chemicals remains challenging because of the lack of mechanism-based therapeutic approaches. Recent studies have shown that transient receptor potential vanilloid 4 (TRPV4), an ion channel expressed in pulmonary tissues, is a crucial mediator of pressure-induced damage associated with ventilator-induced lung injury, heart failure, and infarction. Here, we examined the effects of two novel TRPV4 inhibitors in mice exposed to hydrochloric acid, mimicking acid exposure and acid aspiration injury, and to chlorine gas, a severe chemical threat with frequent exposures in domestic and occupational environments and in transportation accidents. Postexposure treatment with a TRPV4 inhibitor suppressed acid-induced pulmonary inflammation by diminishing neutrophils, macrophages, and associated chemokines and cytokines, while improving tissue pathology. These effects were recapitulated in TRPV4-deficient mice. TRPV4 inhibitors had similar anti-inflammatory effects in chlorine-exposed mice and inhibited vascular leakage, airway hyperreactivity, and increase in elastance, while improving blood oxygen saturation. In both models of lung injury we detected increased concentrations of N-acylamides, a class of endogenous TRP channel agonists. Taken together, we demonstrate that TRPV4 inhibitors are potent and efficacious countermeasures against severe chemical exposures, acting against exaggerated inflammatory responses, and protecting tissue barriers and cardiovascular function. PMID:24838754

Are Rice and Spicy Diet Good for Functional Gastrointestinal Disorders?

PubMed Central

2010-01-01

Rice- and chili-containing foods are common in Asia. Studies suggest that rice is completely absorbed in the small bowel, produces little intestinal gas and has a low allergenicity. Several clinical studies have demonstrated that rice-based meals are well tolerated and may improve gastrointestinal symptoms in functional gastrointestinal disorders (FGID). Chili is a spicy ingredient commonly use throughout Asia. The active component of chili is capsaicin. Capsaicin can mediate a painful, burning sensation in the human gut via the transient receptor potential vanilloid-1 (TRPV1). Recently, the TRPV1 expressing sensory fibers have been reported to increase in the gastrointestinal tract of patients with FGID and visceral hypersensitivity. Acute exposure to capsaicin or chili can aggravate abdominal pain and burning in dyspepsia and IBS patients. Whereas, chronic ingestion of natural capsaicin agonist or chili has been shown to decrease dyspeptic and gastroesophageal reflux disease (GERD) symptoms. The high prevalence of spicy food in Asia may modify gastrointestinal burning symptoms in patients with FGID. Studies in Asia demonstrated a low prevalence of heartburn symptoms in GERD patients in several Asian countries. In conclusion rice is well tolerated and should be advocated as the carbohydrate source of choice for patients with FGID. Although, acute chili ingestion can aggravate abdominal pain and burning symptoms in FGID, chronic ingestion of chili was found to improve functional dyspepsia and GERD symptoms in small randomized, controlled studies. PMID:20535343

Selective disruption of high sensitivity heat activation but not capsaicin activation of TRPV1 channels by pore turret mutations

PubMed Central

Cui, Yuanyuan; Yang, Fan; Cao, Xu; Yarov-Yarovoy, Vladimir

2012-01-01

The capsaicin receptor transient receptor potential vanilloid (TRPV)1 is a highly heat-sensitive ion channel. Although chemical activation and heat activation of TRPV1 elicit similar pungent, painful sensation, the molecular mechanism underlying synergistic activation remains mysterious. In particular, where the temperature sensor is located and whether heat and capsaicin share a common activation pathway are debated. To address these fundamental issues, we searched for channel mutations that selectively affected one form of activation. We found that deletion of the first 10 amino acids of the pore turret significantly reduced the heat response amplitude and shifted the heat activation threshold, whereas capsaicin activation remained unchanged. Removing larger portions of the turret disrupted channel function. Introducing an artificial sequence to replace the deleted region restored sensitive capsaicin activation in these nonfunctional channels. The heat activation, however, remained significantly impaired, with the current exhibiting diminishing heat sensitivity to a level indistinguishable from that of a voltage-gated potassium channel, Kv7.4. Our results demonstrate that heat and capsaicin activation of TRPV1 are structurally and mechanistically distinct processes, and the pore turret is an indispensible channel structure involved in the heat activation process but is not part of the capsaicin activation pathway. Synergistic effect of heat and capsaicin on TRPV1 activation may originate from convergence of the two pathways on a common activation gate. PMID:22412190

Animal Toxins Providing Insights into TRPV1 Activation Mechanism

PubMed Central

Geron, Matan; Hazan, Adina

2017-01-01

Beyond providing evolutionary advantages, venoms offer unique research tools, as they were developed to target functionally important proteins and pathways. As a key pain receptor in the nociceptive pathway, transient receptor potential vanilloid 1 (TRPV1) of the TRP superfamily has been shown to be a target for several toxins, as a way of producing pain to deter predators. Importantly, TRPV1 is involved in thermoregulation, inflammation, and acute nociception. As such, toxins provide tools to understand TRPV1 activation and modulation, a critical step in advancing pain research and the development of novel analgesics. Indeed, the phytotoxin capsaicin, which is the spicy chemical in chili peppers, was invaluable in the original cloning and characterization of TRPV1. The unique properties of each subsequently characterized toxin have continued to advance our understanding of functional, structural, and biophysical characteristics of TRPV1. By building on previous reviews, this work aims to provide a comprehensive summary of the advancements made in TRPV1 research in recent years by employing animal toxins, in particular DkTx, RhTx, BmP01, Echis coloratus toxins, APHCs and HCRG21. We examine each toxin’s functional aspects, behavioral effects, and structural features, all of which have contributed to our current knowledge of TRPV1. We additionally discuss the key features of TRPV1’s outer pore domain, which proves to be the target of the currently discussed toxins. PMID:29035314

Capsaicin modulates acetylcholine release at the myoneural junction.

PubMed

Thyagarajan, Baskaran; Potian, Joseph G; Baskaran, Padmamalini; McArdle, Joseph J

2014-12-05

Transient receptor potential (TRP) proteins are non-selective cation channel proteins that are expressed throughout the body. Previous studies demonstrated the expression of TRP Vanilloid 1 (TRPV1), capsaicin (CAP) receptor, in sensory neurons. Recently, we reported TRPV1 expression in mouse motor nerve terminals [MNTs; (Thyagarajan et al., 2009)], where we observed that CAP protected MNTs from botulinum neurotoxin A (BoNT/A). Phrenic nerve diaphragm nerve muscle preparations (NMP) isolated from isoflurane anesthetized adult mice were analyzed for twitch tension, spontaneous (mEPCs) and nerve stimulus evoked (EPCs) acetylcholine release. When acutely applied to isolated NMP, CAP produced a concentration-dependent decline of twitch tension and produced a significant decline in the amplitude of EPCs and quantal content without any effect on the mEPCs. The suppression of nerve stimulus evoked acetylcholine release by CAP was antagonized by capsazepine (CPZ), a TRPV1 antagonist. CAP did not suppress phrenic nerve stimulus evoked acetylcholine release in TRPV1 knockout mice. Also, CAP treatment, in vitro, interfered with the localization of adapter protein 2 in cholinergic Neuro 2a cells. Wortmannin, (WMN; non-selective phosphoinositol kinase inhibitor), mimicked the effects of CAP by inhibiting the acetylcholine exocytosis. Our data suggest that TRPV1 proteins expressed at the MNT are coupled to the exo-endocytic mechanisms to regulate neuromuscular functions. Copyright © 2014 Elsevier B.V. All rights reserved.

Involvement of TRPV1 and AQP2 in hypertonic stress by xylitol in odontoblast cells.

PubMed

Tokuda, M; Fujisawa, M; Miyashita, K; Kawakami, Y; Morimoto-Yamashita, Y; Torii, M

2015-02-01

To examine the responses of mouse odontoblast-lineage cell line (OLC) cultures to xylitol-induced hypertonic stress. OLCs were treated with xylitol, sucrose, sorbitol, mannitol, arabinose and lyxose. Cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay. The expression of transient receptor potential vanilloids (TRPV) 1, 3 and 4 was detected using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The expression of aquaporin (AQP) 2 was detected using immunofluorescence and Western blotting analysis. The expression of interleukin-6 (IL-6) under xylitol-induced hypertonic stress was assessed using an enzyme-linked immunosorbent assay (ELISA). Small interfering ribonucleic acid (siRNA) for AQP-2 was used to inhibition assay. Xylitol-induced hypertonic stress did not decrease OLC viability, unlike the other sugars tested. OLCs expressed TRPV1, 3 and 4 as well as AQP2. Xylitol inhibited lipopolysaccharide (LPS)-induced IL-6 expression after 3 h of hypertonic stress. TRPV1 mRNA expression was upregulated by xylitol. Costimulation with HgCl2 (AQP inhibitor) and Ruthenium red (TRPV1 inhibitor) decreased cell viability with xylitol stimulation. OLCs treated with siRNA against TRPV1 exhibited decreased cell viability with xylitol stimulation. OLCs have high-cell viability under xylitol-induced hypertonic stress, which may be associated with TRPV1 and AQP2 expressions.

TRPV1 activation improves exercise endurance and energy metabolism through PGC-1α upregulation in mice.

PubMed

Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

2012-03-01

Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance.

Activation of TRPV1 channels inhibits mechanosensitive Piezo channel activity by depleting membrane phosphoinositides

PubMed Central

Borbiro, Istvan; Badheka, Doreen; Rohacs, Tibor

2015-01-01

Capsaicin is an activator of the heat-sensitive TRPV1 (transient receptor potential vanilloid 1) ion channels and has been used as a local analgesic. We found that activation of TRPV1 channels with capsaicin either in dorsal root ganglion neurons or in a heterologous expression system inhibited the mechanosensitive Piezo1 and Piezo2 channels by depleting phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and its precursor PI(4)P from the plasma membrane through Ca2+-induced phospholipase Cδ (PLCδ) activation. Experiments with chemically inducible phosphoinositide phosphatases and receptor-induced activation of PLCβ indicated that inhibition of Piezo channels required depletion of both PI(4)P and PI(4,5)P2. The mechanically activated current amplitudes decreased substantially in the excised inside-out configuration, where the membrane patch containing Piezo1 channels is removed from the cell. PI(4,5)P2 and PI(4)P applied to these excised patches inhibited this decrease. Thus, we concluded that Piezo channel activity requires the presence of phosphoinositides, and the combined depletion of PI(4,5)P2 or PI(4)P reduces channel activity. In addition to revealing a role for distinct membrane lipids in mechanosensitive ion channel regulation, these data suggest that inhibition of Piezo2 channels may contribute to the analgesic effect of capsaicin. PMID:25670203

A nonpungent component of steamed ginger--[10]-shogaol--increases adrenaline secretion via the activation of TRPV1.

PubMed

Iwasaki, Yusaku; Morita, Akihito; Iwasawa, Takahito; Kobata, Kenji; Sekiwa, Youko; Morimitsu, Yasujiro; Kubota, Kikue; Watanabe, Tatsuo

2006-01-01

We investigated the components of ginger that are involved in increasing body temperature. Gingerols ([6,8,10]-gingerols) and shogaols ([6,8,10]-shogaols) having different alkyl carbon chain lengths were targeted. All the gingerols and shogaols increased intracellular calcium concentration in rat transient receptor potential vanilloid subtype 1 (TRPV1)-expressing HEK293 cells via TRPV1. In this regard, the shogaols were more potent than the gingerols. Aversive responses were induced by [6]-, [10]-gingerol, and [6]-shogaol (5 mmol/l) in rats when these compounds were applied to the eye; however, no response was observed in response to [10]-shogaol (5 and 10 mmol/l). [10]-Shogaol induced nociceptive responses via TRPV1 in rats following its subcutaneous injection into the hindpaw; the pungent compound capsaicin (CAP) and [6]-shogaol were observed to have similar effects. Moreover, adrenal catecholamine secretion, which influences energy consumption, was promoted in rats in response to [6]- and [10]-gingerols and [6]- and [10]-shogaols (1.6 micromol/kg, i.v.). [10]-Shogaol-induced adrenaline secretion was inhibited by administration of capsazepine, a TRPV1 antagonist. In conclusion, gingerols and shogaols activated TRPV1 and increased adrenaline secretion. Interestingly, [10]-shogaol is the only nonpungent compound among the gingerols and shogaols, suggesting its usefulness as a functional ingredient in food.

In vitro activation of the neuro-transduction mechanism in sensitive organotypic human skin model.

PubMed

Martorina, Francesca; Casale, Costantino; Urciuolo, Francesco; Netti, Paolo A; Imparato, Giorgia

2017-01-01

Recent advances in tissue engineering have encouraged researchers to endeavor the production of fully functional three-dimensional (3D) thick human tissues in vitro. Here, we report the fabrication of a fully innervated human skin tissue in vitro that recapitulates and replicates skin sensory function. Previous attempts to innervate in vitro 3D skin models did not demonstrate an effective functionality of the nerve network. In our approach, we initially engineer functional human skin tissue based on fibroblast-generated dermis and differentiated epidermis; then, we promote rat dorsal root ganglion (DRG) neurons axon ingrowth in the de-novo developed tissue. Neurofilaments network infiltrates the entire native dermis extracellular matrix (ECM), as demonstrated by immunofluorescence and second harmonic generation (SHG) imaging. To prove sensing functionality of the tissue, we use topical applications of capsaicin, an agonist of transient receptor protein-vanilloid 1 (TRPV1) channel, and quantify calcium currents resulting from variations of Ca ++ concentration in DRG neurons innervating our model. Calcium currents generation demonstrates functional cross-talking between dermis and epidermis compartments. Moreover, through a computational fluid dynamic (CFD) analysis, we set fluid dynamic conditions for a non-planar skin equivalent growth, as proof of potential application in creating skin grafts tailored on-demand for in vivo wound shape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Activation of TRPV4 channels does not mediate inversion of neurovascular coupling after SAH.

PubMed

Koide, Masayo; Wellman, George C

2015-01-01

Neurovascular coupling (NVC) allows increased blood flow to metabolically active neurons and involves the Ca²⁺ -dependent release of vasodilator influences by astrocyte endfeet that encase parenchymal arterioles. We previously reported inversion of NVC from dilation to constriction in brain slices from subarachnoid hemorrhage (SAH) model rats. Corresponding to NVC inversion, there was a marked increase in the amplitude of spontaneous Ca²⁺ oscillations in astrocyte endfeet. Calcium-permeable transient receptor potential vanilloid (TRPV)-4 channels have been reported in astrocyte endfeet, and activators of these channels enhance Ca²⁺ oscillations in healthy animals. Here, we examined the role of TRPV4 channels in the development of high-amplitude spontaneous Ca²⁺ oscillations in astrocyte endfeet and the inversion of neurovascular coupling after SAH. Treatment of brain slices with the TRPV4 channel antagonist, HC-067047 (10 μM), did not alter the amplitude of spontaneous Ca²⁺ oscillations after SAH. In addition, HC-067047 did not inhibit or change SAH-induced inversion of neurovascular coupling. In summary, TRPV4 channels do not appear to be involved in the inversion of neurovascular coupling after SAH. Further studies examining the impact of SAH on additional Ca²⁺ signaling pathways in astrocytes are likely to reveal valuable insights into new therapeutic strategies to advance SAH treatments.

TRPV4 channels stimulate Ca2+-induced Ca2+ release in astrocytic endfeet and amplify neurovascular coupling responses.

PubMed

Dunn, Kathryn M; Hill-Eubanks, David C; Liedtke, Wolfgang B; Nelson, Mark T

2013-04-09

In the CNS, astrocytes are sensory and regulatory hubs that play important roles in cerebral homeostatic processes, including matching local cerebral blood flow to neuronal metabolism (neurovascular coupling). These cells possess a highly branched network of processes that project from the soma to neuronal synapses as well as to arterioles and capillaries, where they terminate in "endfeet" that encase the blood vessels. Ca(2+) signaling within the endfoot mediates neurovascular coupling; thus, these functional microdomains control vascular tone and local perfusion in the brain. Transient receptor potential vanilloid 4 (TRPV4) channels--nonselective cation channels with considerable Ca(2+) conductance--have been identified in astrocytes, but their function is largely unknown. We sought to characterize the influence of TRPV4 channels on Ca(2+) dynamics in the astrocytic endfoot microdomain and assess their role in neurovascular coupling. We identified local TRPV4-mediated Ca(2+) oscillations in endfeet and further found that TRPV4 Ca(2+) signals are amplified and propagated by Ca(2+)-induced Ca(2+) release from inositol trisphosphate receptors (IP3Rs). Moreover, TRPV4-mediated Ca(2+) influx contributes to the endfoot Ca(2+) response to neuronal activation, enhancing the accompanying vasodilation. Our results identify a dynamic synergy between TRPV4 channels and IP3Rs in astrocyte endfeet and demonstrate that TRPV4 channels are engaged in and contribute to neurovascular coupling.

Probing the Effects and Mechanisms of Electroacupuncture at Ipsilateral or Contralateral ST36-ST37 Acupoints on CFA-induced Inflammatory Pain.

PubMed

Lu, Kung-Wen; Hsu, Chao-Kuei; Hsieh, Ching-Liang; Yang, Jun; Lin, Yi-Wen

2016-02-24

Transient receptor potential vanilloid 1 (TRPV1) and associated signaling pathways have been reported to be increased in inflammatory pain signaling. There are accumulating evidences surrounding the therapeutic effect of electroacupuncture (EA). EA can reliably attenuate the increase of TRPV1 in mouse inflammatory pain models with unclear signaling mechanisms. Moreover, the difference in the clinical therapeutic effects between using the contralateral and ipsilateral acupoints has been rarely studied. We found that inflammatory pain, which was induced by injecting the complete Freund's adjuvant (CFA), (2.14 ± 0.1, p < 0.05, n = 8) can be alleviated after EA treatment at either ipsilateral (3.91 ± 0.21, p < 0.05, n = 8) or contralateral acupoints (3.79 ± 0.25, p < 0.05, n = 8). EA may also reduce nociceptive Nav sodium currents in dorsal root ganglion (DRG) neurons. The expression of TRPV1 and associated signaling pathways notably increased after the CFA injection; this expression can be further attenuated significantly in EA treatment. TRPV1 and associated signaling pathways can be prevented in TRPV1 knockout mice, suggesting that TRPV1 knockout mice are resistant to inflammatory pain. Through this study, we have increased the understanding of the mechanism that both ipsilateral and contralateral EA might alter TRPV1 and associated signaling pathways to reduce inflammatory pain.

Heavy metal cations permeate the TRPV6 epithelial cation channel.

PubMed

Kovacs, Gergely; Danko, Tamas; Bergeron, Marc J; Balazs, Bernadett; Suzuki, Yoshiro; Zsembery, Akos; Hediger, Matthias A

2011-01-01

TRPV6 belongs to the vanilloid family of the transient receptor potential channel (TRP) superfamily. This calcium-selective channel is highly expressed in the duodenum and the placenta, being responsible for calcium absorption in the body and fetus. Previous observations have suggested that TRPV6 is not only permeable to calcium but also to other divalent cations in epithelial tissues. In this study, we tested whether TRPV6 is indeed also permeable to cations such as zinc and cadmium. We found that the basal intracellular calcium concentration was higher in HEK293 cells transfected with hTRPV6 than in non-transfected cells, and that this difference almost disappeared in nominally calcium-free solution. Live cell imaging experiments with Fura-2 and NewPort Green DCF showed that overexpression of human TRPV6 increased the permeability for Ca(2+), Ba(2+), Sr(2+), Mn(2+), Zn(2+), Cd(2+), and interestingly also for La(3+) and Gd(3+). These results were confirmed using the patch clamp technique. (45)Ca uptake experiments showed that cadmium, lanthanum and gadolinium were also highly efficient inhibitors of TRPV6-mediated calcium influx at higher micromolar concentrations. Our results suggest that TRPV6 is not only involved in calcium transport but also in the transport of other divalent cations, including heavy metal ions, which may have toxicological implications. Copyright © 2010 Elsevier Ltd. All rights reserved.

Letrozole induced low estrogen levels affected the expressions of duodenal and renal calcium-processing gene in laying hens.

PubMed

Li, Qiao; Zhao, Xingkai; Wang, Shujie; Zhou, Zhenlei

2018-01-01

Estrogen regulates the calcium homeostasis in hens, but the mechanisms involved are still unclear fully. In this study, we investigated whether letrozole (LZ) induced low estrogen levels affected the calcium absorption and transport in layers. In the duodenum, we observed a significant decrease of mRNA expressions of Calbindin-28k (CaBP-28k) and plasma membrane Ca 2+ -ATPase (PMCA 1b) while CaBP-28k protein expression was declined in birds with LZ treatment, and the mRNA levels of duodenal transient receptor potential vanilloid 6 (TRPV6) and Na + /Ca 2+ exchanger 1 (NCX1) were not affected. Interestingly, we observed the different changes in the kidney. The renal mRNA expressions of TRPV6 and NCX1 were unregulated while the PMCA1b was down-regulated in low estrogen layers, however, the CaBP-28k gene and protein expressions were no changed in the kidney. Furthermore, it showed that the duodenal estradiol receptor 2 (ESR2) transcripts rather than parathyroid hormone 1 receptor (PTH1R) and calcitonin receptor (CALCR) played key roles to down-regulate calcium transport in LZ-treated birds. In conclusion, CaBP-28k, PMCA 1b and ESR2 genes in the duodenum may be primary targets for estrogen regulation in order to control calcium homeostasis in hens. Copyright © 2017 Elsevier Inc. All rights reserved.

Characterization of calmodulin binding domains in TRPV2 and TRPV5 C-tails.

PubMed

Holakovska, Blanka; Grycova, Lenka; Bily, Jan; Teisinger, Jan

2011-02-01

The transient receptor potential channels TRPV2 and TRPV5 belong to the vanilloid TRP subfamily. TRPV2 is highly similar to TRPV1 and shares many common properties with it. TRPV5 (and also its homolog TRPV6) is a rather distinct member of the TRPV subfamily. It is distant for being strictly Ca(2+)-selective and features quite different properties from the rest of the TRPV subfamily. It is known that TRP channels are regulated by calmodulin in a calcium-dependent manner. In our study we identified a calmodulin binding site on the C-termini of TRPV2 (654-683) and TRPV5 (587-616) corresponding to the consensus CaM binding motif 1-5-10. The R679 and K681 single mutants of TRPV2 caused a 50% decrease in binding affinity and a double mutation of K661/K664 of the same peptide lowered the binding affinity by up to 75%. A double mutation of R606/K607 and triple mutation of R594/R606/R610 in TRPV5 C-terminal peptide resulted in the total loss of binding affinity to calmodulin. These results demonstrate that the TRPV2 C-tail and TRPV5 C-tail contain calmodulin binding sites and that the basic residues are strongly involved in TRP channel binding to calmodulin.

RANKL-induced TRPV2 expression regulates osteoclastogenesis via calcium oscillations.

PubMed

Kajiya, Hiroshi; Okamoto, Fujio; Nemoto, Tetsuomi; Kimachi, Keiichiro; Toh-Goto, Kazuko; Nakayana, Shuji; Okabe, Koji

2010-11-01

The receptor activator of NFκB ligand (RANKL) induces Ca(2+) oscillations and activates the Nuclear Factor of Activated T cells 1 (NFATc1) during osteoclast differentiation (osteoclastogenesis). Ca(2+) oscillations are an important trigger signal for osteoclastogenesis, however the molecular basis of Ca(2+) permeable influx pathways serving Ca(2+) oscillations has not yet been identified. Using a DNA microarray, we found that Transient Receptor Potential Vanilloid channels 2 (TRPV2) are expressed significantly in RANKL-treated RAW264.7 cells (preosteoclasts) compared to untreated cells. Therefore, we further investigated the expression and functional role of TRPV2 on Ca(2+) oscillations and osteoclastogenesis. We found that RANKL dominantly up-regulates TRPV2 expression in preosteoclasts, and evokes spontaneous Ca(2+) oscillations and a transient inward cation current in a time-dependent manner. TRPV inhibitor ruthenium red and tetracycline-induced TRPV2 silencing significantly decreased both the frequency of Ca(2+) oscillations and the transient inward currents in RANKL-treated preosteoclasts. Silencing of store-operated Ca(2+) entry (SOCE) proteins similarly suppressed both RANKL-induced oscillations and currents in preosteoclasts. Furthermore, suppression of TRPV2 also reduced RANKL-induced NAFTc1 expression, its nuclear translocation, and osteoclastogenesis. In summary, Ca(2+) oscillations in preosteoclasts are triggered by RANKL-dependent TRPV2 and SOCE activation and intracellular Ca(2+) release. Subsequent activation of NFATc1 promotes osteoclastogenesis. Copyright © 2010 Elsevier Ltd. All rights reserved.

A Functional Nuclear Localization Sequence in the C. elegans TRPV Channel OCR-2

PubMed Central

Ezak, Meredith J.; Ferkey, Denise M.

2011-01-01

The ability to modulate gene expression in response to sensory experience is critical to the normal development and function of the nervous system. Calcium is a key activator of the signal transduction cascades that mediate the process of translating a cellular stimulus into transcriptional changes. With the recent discovery that the mammalian Cav1.2 calcium channel can be cleaved, enter the nucleus and act as a transcription factor to control neuronal gene expression, a more direct role for the calcium channels themselves in regulating transcription has begun to be appreciated. Here we report the identification of a nuclear localization sequence (NLS) in the C. elegans transient receptor potential vanilloid (TRPV) cation channel OCR-2. TRPV channels have previously been implicated in transcriptional regulation of neuronal genes in the nematode, although the precise mechanism remains unclear. We show that the NLS in OCR-2 is functional, being able to direct nuclear accumulation of a synthetic cargo protein as well as the carboxy-terminal cytosolic tail of OCR-2 where it is endogenously found. Furthermore, we discovered that a carboxy-terminal portion of the full-length channel can localize to the nucleus of neuronal cells. These results suggest that the OCR-2 TRPV cation channel may have a direct nuclear function in neuronal cells that was not previously appreciated. PMID:21957475

TRPV1 Activation Counters Diet-Induced Obesity Through Sirtuin-1 activation and PRDM-16 Deacetylation in Brown Adipose Tissue

PubMed Central

Baskaran, Padmamalini; Krishnan, Vivek; Fettel, Kevin; Gao, Peng; Zhu, Zhiming; Ren, Jun; Thyagarajan, Baskaran

2017-01-01

Background/Objective An imbalance between energy intake and expenditure leads to obesity. Increasing metabolism and thermogenesis in brown adipose tissue (BAT) can help in overcoming obesity. Here, we investigated the effect of activation of transient receptor potential vanilloid subfamily 1 (TRPV1) in the upregulation of thermogenic proteins in BAT to counter diet-induced obesity. Subjects/Methods We investigated the effect of dietary supplementation of capsaicin (TRPV1 agonist) on the expression of metabolically important thermogenic proteins in BAT of wild type and TRPV1−/− mice that received either a normal chow or high fat (± capsaicin; TRPV1 activator) diet by immunoblotting. We measured the metabolic activity, respiratory quotient and BAT lipolysis. Results CAP antagonized high fat diet (HFD)-induced obesity without decreasing energy intake in mice. HFD suppressed TRPV1 expression and activity in BAT and CAP countered this effect. HFD feeding caused glucose intolerance, hypercholesterolemia and decreased the plasma concentration of glucagon like peptide-1 and CAP countered these effects. HFD suppressed the expression of metabolically important thermogenic genes, ucp-1, bmp8b, sirtuin 1, pgc-1α and prdm-16 in BAT and CAP prevented this effect. CAP increased the phosphorylation of sirtuin 1 and induced an interaction between PPARγ with PRDM-16. Further, CAP treatment, in vitro, decreased the acetylation of PRDM-16, which was antagonized by inhibition of TRPV1 by capsazepine, chelation of intracellular Ca2+ by cell permeable BAPTA-AM or the inhibition of SIRT-1 by EX 527. Further, CAP supplementation, post HFD, promoted weight loss and enhanced the respiratory exchange ratio. CAP did not have any effect in TRPV1−/− mice. Conclusions Our data show that activation of TRPV1 in BAT enhances the expression of SIRT-1, which facilitates the deacetylation and interaction of PPARγ and PRDM-16. These data suggest that TRPV1 activation is a novel strategy to counter diet-induced obesity by enhancing metabolism and energy expenditure. PMID:28104916

Decreased miR-199 augments visceral pain in patients with IBS through translational upregulation of TRPV1.

PubMed

Zhou, QiQi; Yang, Liuqing; Larson, Scott; Basra, Sapreet; Merwat, Shehzad; Tan, Alai; Croce, Carlo; Verne, G Nicholas

2016-05-01

Many patients with irritable bowel syndrome IBS not only have abdominal pain but also may suffer from visceral hypersensitivity and heighted visceral nociception. Moreover, IBS has few effective therapeutic agents and mechanisms of disease are unclear. Our goals were to (i) identify microRNA (miRNA) expression, signalling and targets in human colon (controls; patients with IBS); (ii) verify in vitro, IBS-associated changes in miRNAs, especially miR-199, which is complementary to the transient receptor potential vanilloid type 1 (TRPV1) gene; and (iii) determine whether modulating the expression of miRNAs in vivo, especially miR-199, reverses associated changes and pathological hallmarks of visceral hypersensitivity via TRPV1 signalling. We evaluated 45 patients with diarrhoea-predominant IBS (IBS-D) and 40 controls with (1) visceral pain severity score and (2) colonoscopy with biopsies. miRNA expression was evaluated in human colon following miRNA array analysis. Luciferase assays were done to confirm relationships between miR-199 and TRPV1 expression. A rat model of visceral hypersensitivity was used to study miR-199 and its target gene (TRPV1) expression in dorsal root ganglion (DRG) and colon in vivo. Gut miR-199a/b expression in IBS-D was significantly decreased, which correlated directly with both increased visceral pain scores and TRPV1 expression. In vivo upregulation of miR-199a by intraperitoneal injection of lenti-miR-199a precursors decreased visceral hypersensitivity via diminished TRPV1 signalling. Decreased colonic miR-199a/b correlates with visceral pain in patients with IBS-D. Similarly, reduced miR-199a expression in rat DRG and colon tissue is associated with heightened visceral hypersensitivity. In vivo upregulation of miR-199a decreases visceral pain via inhibition of TRPV1 signalling. Thus, miR-199 precursors may be promising therapeutic candidates for the treatment in patients with visceral pain. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

β-Citronellol, an alcoholic monoterpene with inhibitory properties on the contractility of rat trachea

PubMed Central

Vasconcelos, T.B.; Ribeiro-Filho, H.V.; Lucetti, L.T.; Magalhães, P.J.C.

2015-01-01

β-Citronellol is an alcoholic monoterpene found in essential oils such Cymbopogon citratus (a plant with antihypertensive properties). β-Citronellol can act against pathogenic microorganisms that affect airways and, in virtue of the popular use of β-citronellol-enriched essential oils in aromatherapy, we assessed its pharmacologic effects on the contractility of rat trachea. Contractions of isolated tracheal rings were recorded isometrically through a force transducer connected to a data-acquisition device. β-Citronellol relaxed sustained contractions induced by acetylcholine or high extracellular potassium, but half-maximal inhibitory concentrations (IC50) for K+-elicited stimuli were smaller than those for cholinergic contractions. It also inhibited contractions induced by electrical field stimulation or sodium orthovanadate with pharmacologic potency equivalent to that seen against acetylcholine-induced contractions. When contractions were evoked by selective recruitment of Ca2+ from the extracellular medium, β-citronellol preferentially inhibited contractions that involved voltage-operated (but not receptor-operated) pathways. β-Citronellol (but not verapamil) inhibited contractions induced by restoration of external Ca2+ levels after depleting internal Ca2+ stores with the concomitant presence of thapsigargin and recurrent challenge with acetylcholine. Treatment of tracheal rings with L-NAME, indomethacin or tetraethylammonium did not change the relaxing effects of β-citronellol. Inhibition of transient receptor potential vanilloid subtype 1 (TRPV1) or transient receptor potential ankyrin 1 (TRPA1) receptors with selective antagonists caused no change in the effects of β-citronellol. In conclusion, β-citronellol exerted inhibitory effects on rat tracheal rings, with predominant effects on contractions that recruit Ca2+ inflow towards the cytosol by voltage-gated pathways, whereas it appears less active against contractions elicited by receptor-operated Ca2+ channels. PMID:26648088

Cannabinoids inhibit angiogenic capacities of endothelial cells via release of tissue inhibitor of matrix metalloproteinases-1 from lung cancer cells.

PubMed

Ramer, Robert; Fischer, Sascha; Haustein, Maria; Manda, Katrin; Hinz, Burkhard

2014-09-15

Cannabinoids inhibit tumor neovascularization as part of their tumorregressive action. However, the underlying mechanism is still under debate. In the present study the impact of cannabinoids on potential tumor-to-endothelial cell communication conferring anti-angiogenesis was studied. Cellular behavior of human umbilical vein endothelial cells (HUVEC) associated with angiogenesis was evaluated by Boyden chamber, two-dimensional tube formation and fibrin bead assay, with the latter assessing three-dimensional sprout formation. Viability was quantified by the WST-1 test. Conditioned media (CM) from A549 lung cancer cells treated with cannabidiol, Δ(9)-tetrahydrocannabinol, R(+)-methanandamide or the CB2 agonist JWH-133 elicited decreased migration as well as tube and sprout formation of HUVEC as compared to CM of vehicle-treated cancer cells. Inhibition of sprout formation was further confirmed for cannabinoid-treated A549 cells co-cultured with HUVEC. Using antagonists to cannabinoid-activated receptors the antimigratory action was shown to be mediated via cannabinoid receptors or transient receptor potential vanilloid 1. SiRNA approaches revealed a cannabinoid-induced expression of tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) as well as its upstream trigger, the intercellular adhesion molecule-1, to be causally linked to the observed decrease of HUVEC migration. Comparable anti-angiogenic effects were not detected following direct exposure of HUVEC to cannabinoids, but occurred after addition of recombinant TIMP-1 to HUVEC. Finally, antimigratory effects were confirmed for CM of two other cannabinoid-treated lung cancer cell lines (H460 and H358). Collectively, our data suggest a pivotal role of the anti-angiogenic factor TIMP-1 in intercellular tumor-endothelial cell communication resulting in anti-angiogenic features of endothelial cells. Copyright © 2014 Elsevier Inc. All rights reserved.

Identification of Glycyrrhiza as the rikkunshito constituent with the highest antagonistic potential on heterologously expressed 5-HT3A receptors due to the action of flavonoids

PubMed Central

Herbrechter, Robin; Ziemba, Paul M.; Hoffmann, Katrin M.; Hatt, Hanns; Werner, Markus; Gisselmann, Günter

2015-01-01

The traditional Japanese phytomedicine rikkunshito is traditionally used for the treatment of gastrointestinal motility disorders, cachexia and nausea. These effects indicate 5-HT3 receptor antagonism, due to the involvement of these receptors in such pathophysiological processes. E.g., setrons, specific 5-HT3 receptor antagonists are the strongest antiemetics, developed so far. Therefore, the antagonistic effects of the eight rikkunshito constituents at heterologously expressed 5-HT3Areceptors were analyzed using the two-electrode voltage-clamp technique. The results indicate that tinctures from Aurantii, Ginseng, Zingiberis, Atractylodis and Glycyrrhiza inhibited the 5-HT3A receptor response, whereas the tinctures of Poria cocos, Jujubae and Pinellia exhibited no effect. Surprisingly, the strongest antagonism was found for Glycyrrhiza, whereas the Zingiberis tincture, which is considered to be primarily responsible for the effect of rikkunshito, exhibited the weakest antagonism of 5-HT3A receptors. Rikkunshito contains various vanilloids, ginsenosides and flavonoids, a portion of which show an antagonistic effect on 5-HT3 receptors. A screening of the established ingredients of the active rikkunshito constituents and related substances lead to the identification of new antagonists within the class of flavonoids. The flavonoids (-)-liquiritigenin, glabridin and licochalcone A from Glycyrrhiza species were found to be the most effective inhibitors of the 5-HT-induced currents in the screening. The flavonoids (-)-liquiritigenin and hesperetin from Aurantii inhibited the receptor response in a non-competitive manner, whereas glabridin and licochalcone A exhibited a potential competitive antagonism. Furthermore, licochalcone A acts as a partial antagonist of 5-HT3A receptors. Thus, this study reveals new 5-HT3A receptor antagonists with the aid of increasing the comprehension of the complex effects of rikkunshito. PMID:26191003

Overexpression of TRPV3 Correlates with Tumor Progression in Non-Small Cell Lung Cancer.

PubMed

Li, Xiaolei; Zhang, Qianhui; Fan, Kai; Li, Baiyan; Li, Huifeng; Qi, Hanping; Guo, Jing; Cao, Yonggang; Sun, Hongli

2016-03-24

(1) BACKGROUND: Transient receptor potential vanilloid 3 (TRPV3) is a member of the TRP channels family of Ca(2+)-permeant channels. The proteins of some TRP channels are highly expressed in cancer cells. This study aimed to assess the clinical significance and biological functions of TRPV3 in non-small cell lung cancer (NSCLC); (2) METHODS: Immunohistochemistry was used to detect the expression of TRPV3 in NSCLC tissues and adjacent noncancerous lung tissues. Western blot was used to detect the protein expressions of TRPV3, CaMKII, p-CaMKII, CyclinA, CyclinD, CyclinE1, CDK2, CDK4, and P27. Small interfering RNA was used to deplete TRPV3 expression. A laser scanning confocal microscope was used to measure intracellular calcium concentration ([Ca(2+)]i). Flow cytometry was used to analyze cell cycle; (3) RESULTS: TRPV3 was overexpressed in 65 of 96 (67.7%) human lung cancer cases and correlated with differentiation (p = 0.001) and TNM stage (p = 0.004). Importantly, TRPV3 expression was associated with short overall survival. In addition, blocking or knockdown of TRPV3 could inhibit lung cancer cell proliferation. Moreover, TRPV3 inhibition could decrease [Ca(2+)]i of lung cancer cells and arrest cell cycle at the G1/S boundary. Further results revealed that TRPV3 inhibition decreased expressions of p-CaMKII, CyclinA, CyclinD1, CyclinE, and increased P27 level; (4) CONCLUSIONS: Our findings demonstrate that TRPV3 was overexpressed in NSCLC and correlated with lung cancer progression. TRPV3 activation could promote proliferation of lung cancer cells. TRPV3 might serve as a potential companion drug target in NSCLC.

Permeation and block of TRPV1 channels by the cationic lidocaine derivative QX-314

PubMed Central

Puopolo, Michelino; Binshtok, Alexander M.; Yao, Gui-Lan; Oh, Seog Bae; Woolf, Clifford J.

2013-01-01

QX-314 (N-ethyl-lidocaine) is a cationic lidocaine derivative that blocks voltage-dependent sodium channels when applied internally to axons or neuronal cell bodies. Coapplication of external QX-314 with the transient receptor potential vanilloid 1 protein (TRPV1) agonist capsaicin produces long-lasting sodium channel inhibition in TRPV1-expressing neurons, suggestive of QX-314 entry into the neurons. We asked whether QX-314 entry occurs directly through TRPV1 channels or through a different pathway (e.g., pannexin channels) activated downstream of TRPV1 and whether QX-314 entry requires the phenomenon of “pore dilation” previously reported for TRPV1. With external solutions containing 10 or 20 mM QX-314 as the only cation, inward currents were activated by stimulation of both heterologously expressed and native TRPV1 channels in rat dorsal root ganglion neurons. QX-314-mediated inward current did not require pore dilation, as it activated within several seconds and in parallel with Cs-mediated outward current, with a reversal potential consistent with PQX-314/PCs = 0.12. QX-314-mediated current was no different when TRPV1 channels were expressed in C6 glioma cells, which lack expression of pannexin channels. Rapid addition of QX-314 to physiological external solutions produced instant partial inhibition of inward currents carried by sodium ions, suggesting that QX-314 is a permeant blocker. Maintained coapplication of QX-314 with capsaicin produced slowly developing reduction of outward currents carried by internal Cs, consistent with intracellular accumulation of QX-314 to concentrations of 50–100 μM. We conclude that QX-314 is directly permeant in the “standard” pore formed by TRPV1 channels and does not require either pore dilation or activation of additional downstream channels for entry. PMID:23303863

Structural Determinants of the Transient Receptor Potential 1 (TRPV1) Channel Activation by Phospholipid Analogs*

PubMed Central

Morales-Lázaro, Sara L.; Serrano-Flores, Barbara; Llorente, Itzel; Hernández-García, Enrique; González-Ramírez, Ricardo; Banerjee, Souvik; Miller, Duane; Gududuru, Veeresh; Fells, James; Norman, Derek; Tigyi, Gabor; Escalante-Alcalde, Diana; Rosenbaum, Tamara

2014-01-01

The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal protein that responds to various stimuli, including capsaicin (the pungent compound found in chili peppers), extracellular acid, and basic intracellular pH, temperatures close to 42 °C, and several lipids. Lysophosphatidic acid (LPA), an endogenous lipid widely associated with neuropathic pain, is an agonist of the TRPV1 channel found in primary afferent nociceptors and is activated by other noxious stimuli. Agonists or antagonists of lipid and other chemical natures are known to possess specific structural requirements for producing functional effects on their targets. To better understand how LPA and other lipid analogs might interact and affect the function of TRPV1, we set out to determine the structural features of these lipids that result in the activation of TRPV1. By changing the acyl chain length, saturation, and headgroup of these LPA analogs, we established strict requirements for activation of TRPV1. Among the natural LPA analogs, we found that only LPA 18:1, alkylglycerophosphate 18:1, and cyclic phosphatidic acid 18:1, all with a monounsaturated C18 hydrocarbon chain activate TRPV1, whereas polyunsaturated and saturated analogs do not. Thus, TRPV1 shows a more restricted ligand specificity compared with LPA G-protein-coupled receptors. We synthesized fatty alcohol phosphates and thiophosphates and found that many of them with a single double bond in position Δ9, 10, or 11 and Δ9 cyclopropyl group can activate TRPV1 with efficacy similar to capsaicin. Finally, we developed a pharmacophore and proposed a mechanistic model for how these lipids could induce a conformational change that activates TRPV1. PMID:25035428

Propofol restores TRPV1 sensitivity via a TRPA1-, nitric oxide synthase-dependent activation of PKCε

PubMed Central

Sinharoy, Pritam; Zhang, Hongyu; Sinha, Sayantani; Prudner, Bethany C; Bratz, Ian N; Damron, Derek S

2015-01-01

We previously demonstrated that the intravenous anesthetic, propofol, restores the sensitivity of transient receptor potential vanilloid channel subtype-1 (TRPV1) receptors via a protein kinase C epsilon (PKCε)-dependent and transient receptor potential ankyrin channel subtype-1 (TRPA1)-dependent pathway in sensory neurons. The extent to which the two pathways are directly linked or operating in parallel has not been determined. Using a molecular approach, our objectives of the current study were to confirm that TRPA1 activation directly results in PKCε activation and to elucidate the cellular mechanism by which this occurs. F-11 cells were transfected with complimentary DNA (cDNA) for TRPV1 only or both TRPV1 and TRPA1. Intracellular Ca2+ concentration was measured in individual cells via fluorescence microscopy. An immunoblot analysis of the total and phosphorylated forms of PKCε, nitric oxide synthase (nNOS), and TRPV1 was also performed. In F-11 cells containing both channels, PKCε inhibition prevented the propofol- and allyl isothiocyanate (AITC)-induced restoration of TRPV1 sensitivity to agonist stimulation as well as increased phosphorylation of PKCε and TRPV1. In cells containing TRPV1 only, neither agonist induced PKCε or TRPV1 phosphorylation. Moreover, NOS inhibition blocked propofol-and AITC-induced restoration of TRPV1 sensitivity and PKCε phosphorylation, and PKCε inhibition prevented the nitric oxide donor, SNAP, from restoring TRPV1 sensitivity. Also, propofol-and AITC-induced phosphorylation of nNOS and nitric oxide (NO) production were blocked with the TRPA1-antagonist, HC-030031. These data indicate that the AITC- and propofol-induced restoration of TRPV1 sensitivity is mediated by a TRPA1-dependent, nitric oxide synthase-dependent activation of PKCε. PMID:26171233

Roles of TRPV1 and TRPA1 in Spontaneous Pain from Inflamed Masseter Muscle.

PubMed

Wang, Sheng; Brigoli, Benjamin; Lim, Jongseuk; Karley, Alisha; Chung, Man-Kyo

2018-06-08

Craniofacial muscle pain, such as spontaneous pain and bite-evoked pain, are major symptoms in patients with temporomandibular disorders and infection. However, the underlying mechanisms of muscle pain, especially mechanisms of highly prevalent spontaneous pain, are poorly understood. Recently, we reported that transient receptor potential vanilloid 1 (TRPV1) contributes to spontaneous pain but only marginally contributes to bite-evoked pain during masseter inflammation. Here, we investigated the role of transient receptor potential ankyrin 1 (TRPA1) in spontaneous and bite-evoked pain during masseter inflammation, and dissected the relative contributions of TRPA1 and TRPV1. Masseter inflammation increased mouse grimace scale (MGS) scores and face wiping behaviors. Pharmacological or genetic inhibition of TRPA1 significantly attenuated MGS but not face wiping behaviors. MGS scores were also attenuated by scavenging putative endogenous ligands for TRPV1 or TRPA1. Simultaneous inhibition of TRPA1 by AP18 and TRPV1 by AMG9810 in masseter muscle resulted in robust inhibition of both MGS and face wiping behaviors. Administration of AP18 or AMG9810 to masseter muscle induced conditioned place preference (CPP). The extent of CPP following simultaneous administration of AP18 and AMG9810 was greater than that induced by the individual antagonists. In contrast, inflammation-induced reduction of bite force was not affected by the inhibition of TRPA1 alone or in combination with TRPV1. These results suggest that simultaneous inhibition of TRPV1 and TRPA1 produces additive relief of spontaneous pain, but does not ameliorate bite-evoked pain during masseter inflammation. Our results provide further evidence that distinct mechanisms underlie spontaneous and bite-evoked pain from inflamed masseter muscle. Copyright © 2018. Published by Elsevier Ltd.

Anticonvulsive effects of endocannabinoids; an investigation to determine the role of regulatory components of endocannabinoid metabolism in the Pentylenetetrazol induced tonic- clonic seizures.

PubMed

Zareie, Parisa; Sadegh, Mehdi; Palizvan, Mohammad Reza; Moradi-Chameh, Homeira

2018-06-01

2-Arachidonoylglycerol (2-AG) and anandamide are two major endocannabinoids produced, released and eliminated by metabolic pathways. Anticonvulsive effect of 2-AG and CB1 receptor is well-established. Herein, we designed to investigate the anticonvulsive influence of key components of the 2-AG and anandamide metabolism. Tonic-clonic seizures were induced by an injection of Pentylenetetrazol (80 mg/kg, i.p.) in adult male Wistar rats. Delay and duration for the seizure stages were considered for analysis. Monoacylglycerol lipase blocker (JJKK048; 1 mg/kg) or alpha/beta hydroxylase domain 6 blocker (WWL70; 5 mg/kg) were administrated alone or with 2-AG to evaluate the anticonvulsive potential of these enzymes. To determine the CB1 receptor involvement, its blocker (MJ15; 3 mg/kg) was administrated associated with JJKK048 or WWL70. To assess anandamide anticonvulsive effect, anandamide membrane transporter blocker (LY21813240; 2.5 mg/kg) was used alone or associated with MJ15. Also, fatty acid amide hydrolase blocker (URB597; 1 mg/kg; to prevent intracellular anandamide hydrolysis) were used alone or with AMG21629 (transient receptor potential vanilloid; TRPV1 antagonist; 3 mg/kg). All compounds were dissolved in DMSO and injected i.p., before the Pentylenetetrazol. Both JJKK048 and WWL70 revealed anticonvulsive effect. Anticonvulsive effect of JJKK048 but not WWL70 was CB1 receptor dependent. LY2183240 showed CB1 receptor dependent anticonvulsive effect. However, URB597 revealed a TRPV1 dependent proconvulsive effect. It seems extracellular accumulation of 2-AG or anandamide has anticonvulsive effect through the CB1 receptor, while intracellular anandamide accumulation is proconvulsive through TRPV1.

Segmental transport of Ca²⁺ and Mg²⁺ along the gastrointestinal tract.

PubMed

Lameris, Anke L; Nevalainen, Pasi I; Reijnen, Daphne; Simons, Ellen; Eygensteyn, Jelle; Monnens, Leo; Bindels, René J M; Hoenderop, Joost G J

2015-02-01

Calcium (Ca(2+)) and magnesium (Mg(2+)) ions are involved in many vital physiological functions. Since dietary intake is the only source of minerals for the body, intestinal absorption is essential for normal homeostatic levels. The aim of this study was to characterize the absorption of Ca(2+) as well as Mg(2+) along the gastrointestinal tract at a molecular and functional level. In both humans and mice the Ca(2+) channel transient receptor potential vanilloid subtype 6 (TRPV6) is expressed in the proximal intestinal segments, whereas Mg(2+) channel transient receptor potential melastatin subtype 6 (TRPM6) is expressed in the distal parts of the intestine. A method was established to measure the rate of Mg(2+) absorption from the intestine in a time-dependent manner by use of (25)Mg(2+). In addition, local absorption of Ca(2+) and Mg(2+) in different segments of the intestine of mice was determined by using surgically implanted intestinal cannulas. By these methods, it was demonstrated that intestinal absorption of Mg(2+) is regulated by dietary needs in a vitamin D-independent manner. Also, it was shown that at low luminal concentrations, favoring transcellular absorption, Ca(2+) transport mainly takes place in the proximal segments of the intestine, whereas Mg(2+) absorption predominantly occurs in the distal part of the gastrointestinal tract. Vitamin D treatment of mice increased serum Mg(2+) levels and 24-h urinary Mg(2+) excretion, but not intestinal absorption of (25)Mg(2+). Segmental cannulation of the intestine and time-dependent absorption studies using (25)Mg(2+) provide new ways to study intestinal Mg(2+) absorption. Copyright © 2015 the American Physiological Society.

Pharmacological profiling of the TRPV3 channel in recombinant and native assays

PubMed Central

Grubisha, Olivera; Mogg, Adrian J; Sorge, Jessica L; Ball, Laura-Jayne; Sanger, Helen; Ruble, Cara L A; Folly, Elizabeth A; Ursu, Daniel; Broad, Lisa M

2014-01-01

Background and Purpose Transient receptor potential vanilloid subtype 3 (TRPV3) is implicated in nociception and certain skin conditions. As such, it is an attractive target for pharmaceutical research. Understanding of endogenous TRPV3 function and pharmacology remains elusive as selective compounds and native preparations utilizing higher throughput methodologies are lacking. In this study, we developed medium-throughput recombinant and native cellular assays to assess the detailed pharmacological profile of human, rat and mouse TRPV3 channels. Experimental Approach Medium-throughput cellular assays were developed using a Ca2+-sensitive dye and a fluorescent imaging plate reader. Human and rat TRPV3 pharmacology was examined in recombinant cell lines, while the mouse 308 keratinocyte cell line was used to assess endogenous TRPV3 activity. Key Results A recombinant rat TRPV3 cellular assay was successfully developed after solving a discrepancy in the published rat TRPV3 protein sequence. A medium-throughput, native, mouse TRPV3 keratinocyte assay was also developed and confirmed using genetic approaches. Whereas the recombinant human and rat TRPV3 assays exhibited similar agonist and antagonist profiles, the native mouse assay showed important differences, namely, TRPV3 activity was detected only in the presence of potentiator or during agonist synergy. Furthermore, the native assay was more sensitive to block by some antagonists. Conclusions and Implications Our findings demonstrate similarities but also notable differences in TRPV3 pharmacology between recombinant and native systems. These findings offer insights into TRPV3 function and these assays should aid further research towards developing TRPV3 therapies. Linked Articles This article is part of a themed section on the pharmacology of TRP channels. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-10 PMID:23848361

Overexpression of TRPV3 Correlates with Tumor Progression in Non-Small Cell Lung Cancer

PubMed Central

Li, Xiaolei; Zhang, Qianhui; Fan, Kai; Li, Baiyan; Li, Huifeng; Qi, Hanping; Guo, Jing; Cao, Yonggang; Sun, Hongli

2016-01-01

(1) Background: Transient receptor potential vanilloid 3 (TRPV3) is a member of the TRP channels family of Ca2+-permeant channels. The proteins of some TRP channels are highly expressed in cancer cells. This study aimed to assess the clinical significance and biological functions of TRPV3 in non-small cell lung cancer (NSCLC); (2) Methods: Immunohistochemistry was used to detect the expression of TRPV3 in NSCLC tissues and adjacent noncancerous lung tissues. Western blot was used to detect the protein expressions of TRPV3, CaMKII, p-CaMKII, CyclinA, CyclinD, CyclinE1, CDK2, CDK4, and P27. Small interfering RNA was used to deplete TRPV3 expression. A laser scanning confocal microscope was used to measure intracellular calcium concentration ([Ca2+]i). Flow cytometry was used to analyze cell cycle; (3) Results: TRPV3 was overexpressed in 65 of 96 (67.7%) human lung cancer cases and correlated with differentiation (p = 0.001) and TNM stage (p = 0.004). Importantly, TRPV3 expression was associated with short overall survival. In addition, blocking or knockdown of TRPV3 could inhibit lung cancer cell proliferation. Moreover, TRPV3 inhibition could decrease [Ca2+]i of lung cancer cells and arrest cell cycle at the G1/S boundary. Further results revealed that TRPV3 inhibition decreased expressions of p-CaMKII, CyclinA, CyclinD1, CyclinE, and increased P27 level; (4) Conclusions: Our findings demonstrate that TRPV3 was overexpressed in NSCLC and correlated with lung cancer progression. TRPV3 activation could promote proliferation of lung cancer cells. TRPV3 might serve as a potential companion drug target in NSCLC. PMID:27023518

Impact of capsaicin, an active component of chili pepper, on pathogenic chlamydial growth (Chlamydia trachomatis and Chlamydia pneumoniae) in immortal human epithelial HeLa cells.

PubMed

Yamakawa, Kazuya; Matsuo, Junji; Okubo, Torahiko; Nakamura, Shinji; Yamaguchi, Hiroyuki

2018-02-01

Chlamydia trachomatis is the leading cause of sexually transmitted infections worldwide. Capsaicin, a component of chili pepper, which can stimulate actin remodeling via capsaicin receptor TRPV1 (transient receptor potential vanilloid 1) and anti-inflammatory effects via PPARγ (peroxisome proliferator-activated receptor-γ) and LXRα (liver X receptor α), is a potential candidate to control chlamydial growth in host cells. We examined whether capsaicin could inhibit C. trachomatis growth in immortal human epithelial HeLa cells. Inclusion forming unit and quantitative PCR assays showed that capsaicin significantly inhibited bacterial growth in cells in a dose-dependent manner, even in the presence of cycloheximide, a eukaryotic protein synthesis inhibitor. Confocal microscopic and transmission electron microscopic observations revealed an obvious decrease in bacterial numbers to inclusions bodies formed in the cells. Although capsaicin can stimulate the apoptosis of cells, no increase in cleaved PARP (poly (ADP-ribose) polymerase), an apoptotic indicator, was observed at a working concentration. All of the drugs tested (capsazepine, a TRPV1 antagonist; 5CPPSS-50, an LXRα inhibitor; and T0070907, a PPARγ inhibitor) had no effect on chlamydial inhibition in the presence of capsaicin. In addition, we also confirmed that capsaicin inhibited Chlamydia pneumoniae growth, indicating a phenomena not specific to C. trachomatis. Thus, we conclude that capsaicin can block chlamydial growth without the requirement of host cell protein synthesis, but by another, yet to be defined, mechanism. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Capsaicin-based analgesic balm attenuates the skeletal muscle metaboreflex in healthy humans.

PubMed

Vianna, Lauro C; Fernandes, Igor A; Barbosa, Thales C; Teixeira, André L; Claudio Lucas da Nóbrega, Antonio

2018-04-26

The exercise pressor reflex (EPR) is comprised from group III and IV skeletal muscle afferents and is one of the principal mediators of the cardiovascular response to exercise. In animals, capsaicin-based analgesic balm (CAP) attenuates the pressor response to muscle contraction, indicating the transient receptor potential vanilloid 1 (TRPv1) receptor (localized on the group IV afferent neuron) as an important mediator of the EPR. However, whether these findings can be extrapolated to humans remain unknown. Here, we tested the hypothesis that CAP attenuates blood pressure (BP) and muscle sympathetic nerve activity (MSNA) responses to isolated muscle metaboreflex activation in healthy men. MSNA (microneurography) and beat-to-beat heart hate (HR - electrography) and BP (finger photoplethysmography) were continuously measured in eight healthy males (23{plus minus}5 y) at rest, during isometric handgrip exercise and during post-exercise ischemia (PEI). Trials were performed before, 30 and 60 min after the topical application of CAP (0.1%, CAPZASIN-HP) over the volar forearm of the subject's exercising arm. Isometric exercise evoked increases in mean BP (∆32{plus minus}4 mmHg) and MSNA (∆26{plus minus}5 bursts/min; ∆19{plus minus}5 bursts/100 heart beats). The increases in BP during handgrip were not affected by CAP, but the increase in MSNA was lower after 60-min of CAP application. During PEI, the increases in BP and MSNA were all significantly less than those before CAP (all P<0.05). In conclusion, CAP attenuated BP and sympathetic responses evoked by PEI in humans. These data provide evidence that TRPv1 receptors potentially contribute to the EPR in humans, via its metabolic component.

Structural determinants of the transient receptor potential 1 (TRPV1) channel activation by phospholipid analogs.

PubMed

Morales-Lázaro, Sara L; Serrano-Flores, Barbara; Llorente, Itzel; Hernández-García, Enrique; González-Ramírez, Ricardo; Banerjee, Souvik; Miller, Duane; Gududuru, Veeresh; Fells, James; Norman, Derek; Tigyi, Gabor; Escalante-Alcalde, Diana; Rosenbaum, Tamara

2014-08-29

The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal protein that responds to various stimuli, including capsaicin (the pungent compound found in chili peppers), extracellular acid, and basic intracellular pH, temperatures close to 42 °C, and several lipids. Lysophosphatidic acid (LPA), an endogenous lipid widely associated with neuropathic pain, is an agonist of the TRPV1 channel found in primary afferent nociceptors and is activated by other noxious stimuli. Agonists or antagonists of lipid and other chemical natures are known to possess specific structural requirements for producing functional effects on their targets. To better understand how LPA and other lipid analogs might interact and affect the function of TRPV1, we set out to determine the structural features of these lipids that result in the activation of TRPV1. By changing the acyl chain length, saturation, and headgroup of these LPA analogs, we established strict requirements for activation of TRPV1. Among the natural LPA analogs, we found that only LPA 18:1, alkylglycerophosphate 18:1, and cyclic phosphatidic acid 18:1, all with a monounsaturated C18 hydrocarbon chain activate TRPV1, whereas polyunsaturated and saturated analogs do not. Thus, TRPV1 shows a more restricted ligand specificity compared with LPA G-protein-coupled receptors. We synthesized fatty alcohol phosphates and thiophosphates and found that many of them with a single double bond in position Δ9, 10, or 11 and Δ9 cyclopropyl group can activate TRPV1 with efficacy similar to capsaicin. Finally, we developed a pharmacophore and proposed a mechanistic model for how these lipids could induce a conformational change that activates TRPV1. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

[The mechanism of action of cannabis and cannabinoids].

PubMed

Scholten, W K

2006-01-21

The effect ofcannabis can be explained on the basis of the function of the cannabinoid receptor system, which consists of CB receptors (CB1, CB2), endoligands to activate these receptors and an enzyme--fatty acid amidohydrolase--to metabolize the endoligands. The endoligands of the cannabinoid receptor system are arachidonic acid-like substances, and are called endocannabinoids. Indications exist that the body also contains arachidonic acid-like substances that inhibit fatty acid amido hydrolase. Various cannabinoids have diverse effects on the receptors, functioning as agonists, antagonists or partial antagonists, as well as affecting the vanilloid receptor. Many known effects ofcannabis can be explained on the basis of this mechanism of action as can the use ofcannabis in various conditions including multiple sclerosis, Parkinson's disease, glaucoma, nausea, vomiting and rheumatoid arthritis.

Anti-nociceptive effects of Tanshinone IIA (TIIA) in a rat model of complete Freund's adjuvant (CFA)-induced inflammatory pain.

PubMed

Sun, Shukai; Yin, Yue; Yin, Xin; Cao, Fale; Luo, Daoshu; Zhang, Ting; Li, Yunqing; Ni, Longxing

2012-09-01

Inflammatory pain is an important clinical symptom. The levels of extracellular signal-regulated kinases (ERKs) and the levels of cytokines such as interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α) play important roles in inflammatory pain. Tanshinone IIA (TIIA) is an important component of Danshen, a traditional Chinese medicine that has been commonly used to treat cardiovascular disease. In this study, we investigated the potential anti-inflammatory nociceptive effects of TIIA on complete Freund's adjuvant (CFA)-induced inflammation and inflammatory pain in rats. The effects of TIIA on CFA-induced thermal and mechanical hypersensitivity were investigated using behavioral tests. The levels of ERKs, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transient receptor potential vanilloid 1 (TRPV1) in the fifth segment of the lumbar spinal cord (L5) ganglia were detected by Western blot, and the levels of mRNA and protein production of IL1-β, IL-6 and TNF-α were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immuno sorbent assay (ELISA). In this study, we found that TIIA attenuates the development of CFA-induced mechanical and thermal hypersensitivity. In addition, p-ERK and NF-κB expression levels were inhibited by TIIA, and the levels of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced. Finally, we found that the expression level of TRPV1 was significantly decreased after TIIA injection. This study demonstrated that TIIA has significant anti-nociceptive effects in a rat model of CFA-induced inflammatory pain. TIIA can inhibit the activation of ERK signaling pathways and the expression of pro-inflammatory cytokines. These results suggest that TIIA may be a potential anti-inflammatory and anti-nociceptive drug. Copyright © 2012 Elsevier Inc. All rights reserved.

TRPV2 knockout mice demonstrate an improved cardiac performance following myocardial infarction due to attenuated activity of peri-infarct macrophages

PubMed Central

Cohen, Lena; Hertzberg-Bigelman, Einat; Levy, Ran; Ben-Shoshan, Jeremy; Keren, Gad

2017-01-01

Background We have recently shown that the expression of the transient receptor potential vanilloid 2 channel, TRPV2, is upregulated in the peri-infarct zone 3–5 days following an acute myocardial infarction (AMI). Further analysis has demonstrated that invading monocytes maturing to macrophages merely harbor the documented elevated expression of this channel. Purpose Assess cardiac function in TRPV2-KO mice compared to TRPV2-WT following AMI and analyze the potential involvement of TRPV2-expressing macrophages in the recovery process. Methods TRPV2-KO or WT mice were induced with AMI by ligation of the left anterior descending artery (LAD). In another set of experiments, TRPV2-KO mice induced with AMI, were intravenously (IV) injected with WT or TRPV2-KO peritoneal macrophages in order to directly assess the potential contribution of TRPV2-expressing macrophages to cardiac healing. Cardiac parameters were obtained by echocardiography 1 day and 30 days post infarction. The relative changes in the ejection fraction (EF) and additional cardiac parameters between baseline (day 1) and day 30 were calculated and statistical significance was determined (SPSS). Results The in vivo study showed that while EF was significantly decreased in the WT animals between baseline and day 30, EF was only slightly and insignificantly reduced in the KO animals. Likewise LVESD and LVESA were significantly modified exclusively in the WT animals. Moreover, intravenous administration of peritoneal WT macrophages, but not KO macrophages, significantly reduced survival of post-MI TRPV2-KO mice. Conclusion The data suggest that knockout of the TRPV2 channel may attenuate macrophage-dependent pro-inflammatory processes and result in better cardiac recovery. TRPV2 may thus represent a novel therapeutic target for treatment of patients undergoing an acute MI. PMID:28481959

Primary sensory neuron-specific interference of TRPV1 signaling by adeno-associated virus-encoded TRPV1 peptide aptamer attenuates neuropathic pain

PubMed Central

Xiang, Hongfei; Liu, Zhen; Wang, Fei; Xu, Hao; Roberts, Christopher; Fischer, Gregory; Stucky, Cheryl L; Dean, Caron; Pan, Bin; Hogan, Quinn H; Yu, Hongwei

2017-01-01

Background TRPV1 (transient receptor potential vanilloid subfamily member 1) is a pain signaling channel highly expressed in primary sensory neurons. Attempts for analgesia by systemic TRPV1 blockade produce undesirable side effects, such as hyperthermia and impaired heat pain sensation. One approach for TRPV1 analgesia is to target TRPV1 along the peripheral sensory pathway. Results For functional blockade of TRPV1 signaling, we constructed an adeno-associated virus (AAV) vector expressing a recombinant TRPV1 interfering peptide aptamer, derived from a 38mer tetrameric assembly domain (TAD), encompassing residues 735 to 772 of rat TRPV1, fused to the C-terminus of enhanced green fluorescent protein (EGFP). AAV-targeted sensory neurons expressing EGFP-TAD after vector injection into the dorsal root ganglia (DRG) revealed decreased inward calcium current and diminished intracellular calcium accumulation in response to capsaicin, compared to neurons of naïve or expressing EGFP alone. To examine the potential for treating neuropathic pain, AAV-EGFP-TAD was injected into fourth and fifth lumbar (L) DRGs of rats subjected to neuropathic pain by tibial nerve injury (TNI). Results showed that AAV-directed selective expression of EGFP-TAD in L4/L5 DRG neuron somata, and their peripheral and central axonal projections can limit TNI-induced neuropathic pain behavior, including hypersensitivity to heat and, to a less extent, mechanical stimulation. Conclusion Selective inhibition of TRPV1 activity in primary sensory neurons by DRG delivery of AAV-encoded analgesic interfering peptide aptamers is efficacious in attenuation of neuropathic pain. With further improvements of vector constructs and in vivo application, this approach might have the potential to develop as an alternative gene therapy strategy to treat chronic pain, especially heat hypersensitivity, without complications due to systemic TRPV1 blockade. PMID:28604222

The research of the possible mechanism and the treatment for capsaicin-induced cough.

PubMed

Zhang, Li; Sun, Tieying; Liu, Longteng; Wang, Lifang

2018-04-01

Unexplained chronic cough (UCC) affects millions of patients worldwide. New therapeutic approaches to this condition are urgently needed, since current treatment options provide only symptomatic relief. Cough reflex hypersensitivity has been shown to play an important role in the pathogenesis of UCC. The transient receptor potential vanilloid type 1 (TRPV1) is present on peripheral terminals of airway sensory nerves and modulation of its activity represents a potential target for the pharmacological treatment of UCC. The aim of this study was to explore the efficacy and the possible mechanism of SB705498, a TRPV1 antagonist, for cough in a capsaicin-induced cough animal model (i.e. guinea pigs). Induction of cough by capsaicin was successfully implemented in the guinea pigs, and the animals that met the inclusion criteria were randomly divided into four treatment groups: (1) Saline inhalation group (NSInh group, N = 10, negative control group), (2) Codeine phosphate intraperitoneal injection group (CPInp group, N = 10, positive control group), (3) SB705498 inhalation group (SBInh group, N = 10), (4) SB705498 intragastric administration group (SBIng group, N = 10). After treatment with above compounds, the capsaicin-induced cough experiment was performed again. The cough numbers and the cough incubation periods were recorded to evaluate the antitussive effect of SB705498. Enzyme-linked immunosorbent assay (ELISA) testing and Immunohistochemistry (IHC) staining for substance P (SP), calcitonin gene related peptide (CGRP) and neurokinin A (NKA) expression in lung and brain tissues were performed as an indication of neurogenic inflammation. Hematoxylin-Eosin (H&E) staining was used to observe the pathology morphology of lung and brain tissues. When the CPInp, SBInh and SBIng groups were compared to the NSInh group, the cough numbers were significantly reduced (p < .001), while the cough incubation periods were significantly prolonged (P < .001). In addition, the expression of SP, CGRP and NKA in lung and brain tissue was reduced (P < .05). None of the animals in the four groups exhibited lung and brain parenchymal inflammation. The results from this study showed that SB705498 had a significant antitussive effect, could reduce the neurogenic inflammation by reducing the expression of SP, CGRP and NKA in a capsaicin-induced cough model of guinea pigs. The results further indicated that TRPV1 played an important role in UCC and SB705498 might be a promising therapeutic agent for UCC. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mother root of Aconitum carmichaelii Debeaux exerts antinociceptive effect in Complet Freund's Adjuvant-induced mice: roles of dynorpin/kappa-opioid system and transient receptor potential vanilloid type-1 ion channel.

PubMed

Wang, Chao; Sun, Danni; Liu, Chunfang; Zhu, Chunyan; Jing, Xianghong; Chen, Shuping; Liu, Cuiling; Zhi, Kai; Xu, Tengfei; Wang, Hui; Liu, Junling; Xu, Ying; Liu, Zhiqiang; Lin, Na

2015-08-30

Processed Chuanwu (PCW), the mother root of Aconitum carmichaelii Debeauxv, has been widely used as a classic Traditional Chinese Medicine for pain relieve for over two millennia clinically. However, its action on chronic inflammatory pain has not been clarified. Here, we investigated the antinociceptive effect of PCW in complete freund's adjuvant (CFA)-induced mice and its possible mechanisms associated with opioid system and TRPV1 ion channel. Male ICR mice were intraplantarly injected with CFA. PCW (0.34, 0.68 and 1.35 g/kg) was orally given to mice once a day for 7 days. Von frey hairs and planter test were assessed to evaluate the antinociceptive effect of PCW. To investigate the participation of dynorphin/opioid system in PCW antinociception, subtype-specific opioid receptor antagonists or anti-dynorphin A antiserum were used. To eliminate other central mechanisms that contribute to PCW antinociception, hot plate (50 °C) test were performed. Further, involvements of TRPV1 in PCW antinociception were evaluated in CFA-induced TRPV1(-/-) and TRPV1(+/+) C57BL/6 male mice, and in capsaicin-induced nociception ICR naive mice pretreated with nor-BNI. Meanwhile, calcium imaging was performed in HEK293T-TRPV1 cells. Finally, rotarod, open-field tests and body temperature measurement were carried out to assess side effects of PCW. PCW dose-dependently attenuated mechanical and heat hypersensitivities with no tolerance, which could be partially attenuated by coadministration of k-opioid receptor antagonist nor-binaltorphimine (nor-BNI) or anti-dynorphin A (1-13) antiserum. And PCW antinociception was totally erased by pretreatment with nor-BNI in the hot plate test. In addition, PCW antinociception was decreased in TRPV1(-/-) mice compared to TRPV1(+/+) group. And PCW still manifested inhibitory effects in capsaicin-induced nociception with nor-BNI pretreatment. PCW significantly inhibited capsaicin-induced calcium influx in HEK293T-TRPV1 cells. Finally, no detectable side effects were found in naive mice treated with PCW. This study shows PCW's potent antinociceptive effect in inflammatory conditions without obvious side effects. This effect may result from the activation of κ-opioid receptor via dynorpin release and the inhibition of TRPV1. These findings indicate that PCW might be a potential agent for the management of chronic inflammatory pain.

Desalted Duck Egg White Peptides Promote Calcium Uptake and Modulate Bone Formation in the Retinoic Acid-Induced Bone Loss Rat and Caco-2 Cell Model.

PubMed

Hou, Tao; Liu, Yanshuang; Kolba, Nikolai; Guo, Danjun; He, Hui

2017-05-12

Desalted duck egg white peptides (DPs) have been proven to promote calcium uptake in Caco-2 cells and rats treated with a calcium-deficient diet. The retinoic acid-induced bone loss model was used to evaluate the effect of DPs on calcium absorption and bone formation. Three-month-old Wistar female rats were treated with 0.9% saline, DPs (800 mg/kg), or alendronate (5 mg/kg) for three weeks immediately after retinoic acid treatment (80 mg/kg) once daily for two weeks. The model group was significantly higher in serum bone alkaline phosphatase than the other three groups ( p < 0.05), but lower in calcium absorption rate, serum osteocalcin, bone weight index, bone calcium content, bone mineral density, and bone max load. After treatment with DPs or alendronate, the absorption rate increased and some serum and bone indices recovered. The morphology results indicated bone tissue form were ameliorated and numbers of osteoclasts decreased after supplementation with DPs or alendronate. The in vitro study showed that the transient receptor potential vanilloid 6 (TRPV6) calcium channel was the main transport pathway of both DPs and Val-Ser-Glu-Glu peptitde (VSEE), which was identified from DPs. Our results indicated that DPs could be a promising alternative to current therapeutic agents for bone loss because of the promotion of calcium uptake and regulation of bone formation.

Pirt contributes to uterine contraction-induced pain in mice.

PubMed

Wang, Changming; Wang, Zhongli; Yang, Yan; Zhu, Chan; Wu, Guanyi; Yu, Guang; Jian, Tunyu; Yang, Niuniu; Shi, Hao; Tang, Min; He, Qian; Lan, Lei; Liu, Qin; Guan, Yun; Dong, Xinzhong; Duan, Jinao; Tang, Zongxiang

2015-09-17

Uterine contraction-induced pain (UCP) represents a common and severe form of visceral pain. Nerve fibers that innervate uterine tissue express the transient receptor potential vanilloid channel 1 (TRPV1), which has been shown to be involved in the perception of UCP. The phosphoinositide-interacting regulator of TRP (Pirt) may act as a regulatory subunit of TRPV1. The intraperitoneal injection of oxytocin into female mice after a 6-day priming treatment with estradiol benzoate induces writhing responses, which reflect the presence of UCP. Here, we first compared writhing response between Pirt (+/+) and Pirt (-/-) mice. Second, we examined the innervation of Pirt-expressing nerves in the uterus of Pirt (-/-) mice by immunofluorescence and two-photon microscopy. Third, we identified the soma of dorsal root ganglion (DRG) neurons that innerve the uterus using retrograde tracing and further characterized the neurochemical properties of these DRG neurons. Finally, we compared the calcium response of capsaicin between DRG neurons from Pirt (+/+) and Pirt (-/-) mice. We found that the writhing responses were less intensive in Pirt (-/-) mice than in Pirt (+/+) mice. We also observed Pirt-expressing nerve fibers in the myometrium of the uterus, and that retrograde-labeled cells were small-diameter, unmyelinated, and Pirt-positive DRG neurons. Additionally, we found that the number of capsaicin-responding neurons and the magnitude of evoked calcium response were markedly reduced in DRG neurons from Pirt (-/-) mice. Taken together, we speculate that Pirt plays an important role in mice uterine contraction-induced pain.

Role of membrane cholesterol in spontaneous exocytosis at frog neuromuscular synapses: reactive oxygen species–calcium interplay

PubMed Central

Petrov, Alexey M; Yakovleva, Anastasiya A; Zefirov, Andrey L

2014-01-01

Using electrophysiological and optical techniques, we studied the mechanisms by which cholesterol depletion stimulates spontaneous transmitter release by exocytosis at the frog neuromuscular junction. We found that methyl-β-cyclodextrin (MCD, 10 mm)-mediated exhaustion of cholesterol resulted in the enhancement of reactive oxygen species (ROS) production, which was prevented by the antioxidant N-acetyl cysteine (NAC) and the NADPH oxidase inhibitor apocynin. An increase in ROS levels occurred both extra- and intracellularly, and it was associated with lipid peroxidation in synaptic regions. Cholesterol depletion provoked a rise in the intracellular Ca2+ concentration, which was diminished by NAC and transient receptor potential vanilloid (TRPV) channel blockers (ruthenium red and capsazepine). By contrast, the MCD-induced rise in [Ca2+]i remained unaffected if Ca2+ release from endoplasmic stores was blocked by TMB8 (8-(diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride). The effects of cholesterol depletion on spontaneous release and exocytosis were significantly reduced by the antioxidant, intracellular Ca2+ chelation with BAPTA-AM and blockers of TRPV channels. Bath application of the calcineurin antagonist cyclosporine A blocked MCD-induced enhancement of spontaneous release/exocytosis, whereas okadaic acid, an inhibitor of phosphatases PP1 and PP2A, had no effect. Thus, our findings indicate that enhancement of spontaneous exocytosis induced by cholesterol depletion may depend on ROS generation, leading to an influx of Ca2+ via TRPV channels and, subsequently, activation of calcineurin. PMID:25326454

Probing the Effects and Mechanisms of Electroacupuncture at Ipsilateral or Contralateral ST36–ST37 Acupoints on CFA-induced Inflammatory Pain

PubMed Central

Lu, Kung-Wen; Hsu, Chao-Kuei; Hsieh, Ching-Liang; Yang, Jun; Lin, Yi-Wen

2016-01-01

Transient receptor potential vanilloid 1 (TRPV1) and associated signaling pathways have been reported to be increased in inflammatory pain signaling. There are accumulating evidences surrounding the therapeutic effect of electroacupuncture (EA). EA can reliably attenuate the increase of TRPV1 in mouse inflammatory pain models with unclear signaling mechanisms. Moreover, the difference in the clinical therapeutic effects between using the contralateral and ipsilateral acupoints has been rarely studied. We found that inflammatory pain, which was induced by injecting the complete Freund’s adjuvant (CFA), (2.14 ± 0.1, p < 0.05, n = 8) can be alleviated after EA treatment at either ipsilateral (3.91 ± 0.21, p < 0.05, n = 8) or contralateral acupoints (3.79 ± 0.25, p < 0.05, n = 8). EA may also reduce nociceptive Nav sodium currents in dorsal root ganglion (DRG) neurons. The expression of TRPV1 and associated signaling pathways notably increased after the CFA injection; this expression can be further attenuated significantly in EA treatment. TRPV1 and associated signaling pathways can be prevented in TRPV1 knockout mice, suggesting that TRPV1 knockout mice are resistant to inflammatory pain. Through this study, we have increased the understanding of the mechanism that both ipsilateral and contralateral EA might alter TRPV1 and associated signaling pathways to reduce inflammatory pain. PMID:26906464

Functional interaction of TRPV4 channel protein with annexin A2 in DRG.

PubMed

Ning, Liping; Wang, Chuanwei; Ding, Xinli; Zhang, Yang; Wang, Xuping; Yue, Shouwei

2012-09-01

Transient receptor potential vanilloid 4 (TRPV4) is a Ca(2+)-permeable, non-selective cation channel that is involved in the transmission of pain signals mediated by dorsal root ganglion (DRG). Annexin A2 belongs to a class of membrane-binding proteins that plays an important role in the regulation of ion channels. Nevertheless, little is known about the interaction between them in DRG. In this paper, we evaluated the functional interaction of TRPV4 with annexin A2 in DRG. We have used immunocytochemistry and co-immunoprecipitation assays to investigate the interaction between annexin A2 and TRPV4 in DRG. The role of annexin A2 in the regulation of TRPV4 activity in DRG was further verified by measurement of intracellular free calcium concentrations ([Ca(2+)](i)) and substance P (SP) release. First, annexin A2 was showed partial co-localization with TRPV4 in DRG neurons. Then, annexin A2 and TRPV4 were co-precipitated with each other in DRG lysates. Furthermore, the downregulation of annexin A2 using specific small interfering RNA significantly inhibited Ca(2+) influx and SP mediated by TRPV4. Our results provide evidence that annexin A2 is associated with TRPV4 and regulates TRPV4-mediated Ca(2+) influx and SP release in DRG neurons. The objective of this work is to determine the influence of annexin A2 on TRPV4 in DRG neurons, which may be the basis for treatment of pain relief.

Involvement of MrgprC in Electroacupuncture Analgesia for Attenuating CFA-Induced Thermal Hyperalgesia by Suppressing the TRPV1 Pathway.

PubMed

Liu, Ying-Jun; Lin, Xiao-Xi; Fang, Jian-Qiao; Fang, Fang

2018-01-01

Mas-related G-protein-coupled receptor C (MrgprC) plays an important role in modulating chronic inflammatory pain. Electroacupuncture (EA) has a satisfactory analgesic effect on chronic pain. This study aimed to investigate the involvement of MrgprC and its transient receptor potential vanilloid 1 (TRPV1) pathway in EA analgesia in chronic inflammatory pain. Chronic inflammatory pain was induced by subcutaneously injecting complete Freund's adjuvant (CFA) into the left hind paw. EA (2/100 Hz) stimulation was administered. MrgprC siRNAs were intrathecally administered to inhibit MrgprC expression, and bovine adrenal medulla 8-22 (BAM8-22) was used to activate MrgprC. The mechanical allodynia was decreased by EA significantly since day 3. The piled analgesic effect of EA was partially blocked by 6 intrathecal administrations of MrgprC siRNA. Both EA and BAM8-22 could downregulate the expression of TRPV1 and PKC in both the DRG and the SCDH. Both EA and BAM8-22 could also decrease the TRPV1 translocation and p-TRPV1 level in both the DRG and the SCDH. The effects of EA on PKC ε , TRPV1 translocation, and p-TRPV1 in both the DRG and the SCDH were reversed by MrgprC siRNA. The results indicated that MrgprC played crucial roles in chronic pain modulation and was involved in EA analgesia partially through the regulation of TRPV1 function at the DRG and SCDH levels.

Correlation between Urothelial Differentiation and Sensory Proteins P2X3, P2X5, TRPV1, and TRPV4 in Normal Urothelium and Papillary Carcinoma of Human Bladder

PubMed Central

Sterle, Igor; Zupančič, Daša; Romih, Rok

2014-01-01

Terminal differentiation of urothelium is a prerequisite for blood-urine barrier formation and enables normal sensory function of the urinary bladder. In this study, urothelial differentiation of normal human urothelium and of low and high grade papillary urothelial carcinomas was correlated with the expression and localization of purinergic receptors (P2X3, and P2X5) and transient receptor potential vanilloid channels (TRPV1, and TRPV4). Western blotting and immunofluorescence of uroplakins together with scanning electron microscopy of urothelial apical surface demonstrated terminal differentiation of normal urothelium, partial differentiation of low grade carcinoma, and poor differentiation of high grade carcinoma. P2X3 was expressed in normal urothelium as well as in low grade carcinoma and in both cases immunolabeling was stronger in the superficial cells. P2X3 expression decreased in high grade carcinoma. P2X5 expression was detected in normal urothelium and in high grade carcinoma, while in low grade carcinoma its expression was diminished. The expression of TRPV1 decreased in low grade and even more in high grade carcinoma when compared with normal urothelium, while TRPV4 expression was unchanged in all samples. Our results suggest that sensory proteins P2X3 and TRPV1 are in correlation with urothelial differentiation, while P2X5 and TRPV4 have unique expression patterns. PMID:24868547

Correlation between urothelial differentiation and sensory proteins P2X3, P2X5, TRPV1, and TRPV4 in normal urothelium and papillary carcinoma of human bladder.

PubMed

Sterle, Igor; Zupančič, Daša; Romih, Rok

2014-01-01

Terminal differentiation of urothelium is a prerequisite for blood-urine barrier formation and enables normal sensory function of the urinary bladder. In this study, urothelial differentiation of normal human urothelium and of low and high grade papillary urothelial carcinomas was correlated with the expression and localization of purinergic receptors (P2X3, and P2X5) and transient receptor potential vanilloid channels (TRPV1, and TRPV4). Western blotting and immunofluorescence of uroplakins together with scanning electron microscopy of urothelial apical surface demonstrated terminal differentiation of normal urothelium, partial differentiation of low grade carcinoma, and poor differentiation of high grade carcinoma. P2X3 was expressed in normal urothelium as well as in low grade carcinoma and in both cases immunolabeling was stronger in the superficial cells. P2X3 expression decreased in high grade carcinoma. P2X5 expression was detected in normal urothelium and in high grade carcinoma, while in low grade carcinoma its expression was diminished. The expression of TRPV1 decreased in low grade and even more in high grade carcinoma when compared with normal urothelium, while TRPV4 expression was unchanged in all samples. Our results suggest that sensory proteins P2X3 and TRPV1 are in correlation with urothelial differentiation, while P2X5 and TRPV4 have unique expression patterns.

Opposing actions of TRPV4 channel activation in the lung vasculature.

PubMed

Ke, Sun-Kui; Chen, Lan; Duan, Hong-Bing; Tu, Yuan-Rong

2015-12-01

Transient receptor potential vanilloid 4 (TRPV4) calcium channels are known to promote endothelium-dependent relaxation of mouse mesenteric arteries but TRPV4's role in the pulmonary vasculature is uncertain. Thus, we characterized TRPV4 channel vascular tone regulation in mouse main pulmonary artery rings and in the isolated perfused pulmonary circulation and studied possible mechanisms behind these characterizations. Using myography and a TRPV4 specific agonist GSK1016790A in a C57BL/6 WT mouse model of isolated constant-flow lung perfusion, we studied vascular tone regulation in arterial rings from the main left and right pulmonary arteries and vascular resistance of the intra-pulmonary circulation beyond the second branches of the pulmonary arteries. Removal of the endothelium confirmed endothelial dependence. GSK1016790A relaxed the main pulmonary artery (EC50 4 × 10(-8)mol/L), which was inhibited by removal of the endothelium from main pulmonary artery rings. GSK1016790A significantly increased vascular resistance of the pulmonary circulation in isolated perfused lungs, but these effects were inhibited by a TRPV4 antagonist AB159908. A nitric oxide inhibitor NG-nitro-L-arginine methyl ester (L-NAME) and K(+) channel blockers apamin plus charybdotoxin (ChTx) significantly inhibited GSK1016790A in the main pulmonary artery and in an isolated perfused lung in vitro. Activated TRPV4 channels increase pulmonary vascular resistance and vasodilate the main pulmonary artery. Copyright © 2015 Elsevier B.V. All rights reserved.

Aural stimulation with capsaicin ointment improved swallowing function in elderly patients with dysphagia: a randomized, placebo-controlled, double-blind, comparative study.

PubMed

Kondo, Eiji; Jinnouchi, Osamu; Nakano, Seiichi; Ohnishi, Hiroki; Kawata, Ikuji; Okamoto, Hidehiko; Takeda, Noriaki

2017-01-01

The aim of this study was to assess whether aural stimulation with ointment containing capsaicin improves swallowing function in elderly patients with dysphagia. A randomized, placebo-controlled, double-blind, comparative study. Secondary hospital. Twenty elderly dysphagic patients with a history of cerebrovascular disorder or Parkinson's disease were randomly divided into two groups: 10 receiving aural stimulation with 0.025% capsaicin ointment and 10 stimulated with placebo. The ointments were applied to the external auditory canal with a cotton swab. Then, swallowing of a bolus of blue-dyed water was recorded using transnasal videoendoscopy, and the swallowing function was evaluated according to both endoscopic swallowing scoring and Sensory-Motor-Reflex-Clearance (SMRC) scale. The sum of endoscopic swallowing scores was significantly decreased 30 and 60 min after a single administration in patients treated with capsaicin, but not with placebo. Reflex score, but not Sensory, Motion and Clearance scores, of the SMRC scale was significantly increased 5, 30 and 60 min after single administration in patients treated with capsaicin, but not with placebo. No patient showed signs of adverse effects. As capsaicin is an agonist of the transient receptor potential vanilloid 1 (TRPV1), these findings suggest that improvement of the swallowing function, especially glottal closure and cough reflexes, in elderly dysphagic patients was due to TRPV1-mediated aural stimulation of vagal Arnold's nerve with capsaicin, but not with a nonspecific mechanical stimulation with a cotton swab.

TRPV1 activation improves exercise endurance and energy metabolism through PGC-1α upregulation in mice

PubMed Central

Luo, Zhidan; Ma, Liqun; Zhao, Zhigang; He, Hongbo; Yang, Dachun; Feng, Xiaoli; Ma, Shuangtao; Chen, Xiaoping; Zhu, Tianqi; Cao, Tingbing; Liu, Daoyan; Nilius, Bernd; Huang, Yu; Yan, Zhencheng; Zhu, Zhiming

2012-01-01

Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance. PMID:22184011

Involvement of peripheral artemin signaling in tongue pain: possible mechanism in burning mouth syndrome.

PubMed

Shinoda, Masamichi; Takeda, Mamoru; Honda, Kuniya; Maruno, Mitsuru; Katagiri, Ayano; Satoh-Kuriwada, Shizuko; Shoji, Noriaki; Tsuchiya, Masahiro; Iwata, Koichi

2015-12-01

Burning mouth syndrome is characterized by altered sensory qualities, namely tongue pain hypersensitivity. We found that the mRNA expression of Artemin (Artn) in the tongue mucosa of patients with burning mouth syndrome was significantly higher than that of control subjects, and we developed a mouse model of burning mouth syndrome by application of 2,4,6-trinitrobenzene sulfonic acid (TNBS) diluted with 50% ethanol to the dorsum of the tongue. TNBS treatment to the tongue induced persistent, week-long, noninflammatory tongue pain and a significant increase in Artn expression in the tongue mucosa and marked tongue heat hyperalgesia. Following TNBS treatment, the successive administration of the transient receptor potential vanilloid 1 (TRPV1) antagonist SB366791 or neutralizing anti-Artn antibody completely inhibited the heat hyperalgesia. The number of glial cell line-derived neurotrophic factor family receptor α3 (GFRα3)-positive and TRPV1-positive trigeminal ganglion (TG) neurons innervating the tongue significantly increased following TNBS treatment and was significantly reduced by successive administration of neutralizing anti-Artn antibody. The capsaicin-induced current in TG neurons innervating the tongue was enhanced following TNBS treatment and was inhibited by local administration of neutralizing anti-Artn antibody to the tongue. These results suggest that the overexpression of Artn in the TNBS-treated tongue increases the membrane excitability of TG neurons innervating the tongue by increasing TRPV1 sensitivity, which causes heat hyperalgesia. This model may be useful for the study of tongue pain hypersensitivity associated with burning mouth syndrome.

Injured nerve-derived COX2/PGE2 contributes to the maintenance of neuropathic pain in aged rats.

PubMed

Ma, Weiya; Chabot, Jean-Guy; Vercauteren, Freya; Quirion, Remi

2010-07-01

Neuropathic pain (NeP) is a debilitating disease afflicting mostly the aged population. Inflammatory responses in injured nerves play a pivotal role in the pathogenesis of NeP. Injured nerve derived cyclooxygenase 2/prostaglandin E2 (COX2/PGE2) contributes to the genesis of NeP at the early stage in young rats. Here we show that COX2/PGE2 is involved in the maintenance of NeP at a chronic stage in aged rats. Eighteen months after partial sciatic nerve ligation (PSNL), NeP remained prominent in aged rats. COX2 expressing macrophages and PGE2 levels were increased in injured nerves. PGE2 receptors (EP1 and EP4) and pain-related ion channel transient receptor potential vanilloid-1 (TRPV1) were increased in the ipsilateral dorsal root ganglion (DRG) neurons of aged PSNL rats. Perineural injection of a selective COX2 inhibitor NS-398 relieved NeP, reversed PSNL increased expression of EP1, EP4 and TRPV1 and suppressed the levels of pain-related peptide substance P and calcitonin gene-related peptide in DRG neurons. These data suggest that injured nerve-derived PGE2 contributes to the maintenance of NeP at the chronic stage in aged rats. Chronically facilitating the synthesis of pain-related molecules in nociceptive DRG neurons is a novel mechanism underpinning the contribution of PGE2. Copyright 2008 Elsevier Inc. All rights reserved.

Cannabinoids for Symptom Management and Cancer Therapy: The Evidence.

PubMed

Davis, Mellar P

2016-07-01

Cannabinoids bind not only to classical receptors (CB1 and CB2) but also to certain orphan receptors (GPR55 and GPR119), ion channels (transient receptor potential vanilloid), and peroxisome proliferator-activated receptors. Cannabinoids are known to modulate a multitude of monoamine receptors. Structurally, there are 3 groups of cannabinoids. Multiple studies, most of which are of moderate to low quality, demonstrate that tetrahydrocannabinol (THC) and oromucosal cannabinoid combinations of THC and cannabidiol (CBD) modestly reduce cancer pain. Dronabinol and nabilone are better antiemetics for chemotherapy-induced nausea and vomiting (CINV) than certain neuroleptics, but are not better than serotonin receptor antagonists in reducing delayed emesis, and cannabinoids have largely been superseded by neurokinin-1 receptor antagonists and olanzapine; both cannabinoids have been recommended for breakthrough nausea and vomiting among other antiemetics. Dronabinol is ineffective in ameliorating cancer anorexia but does improve associated cancer-related dysgeusia. Multiple cancers express cannabinoid receptors directly related to the degree of anaplasia and grade of tumor. Preclinical in vitro and in vivo studies suggest that cannabinoids may have anticancer activity. Paradoxically, cannabinoid receptor antagonists also have antitumor activity. There are few randomized smoked or vaporized cannabis trials in cancer on which to judge the benefits of these forms of cannabinoids on symptoms and the clinical course of cancer. Smoked cannabis has been found to contain Aspergillosis. Immunosuppressed patients should be advised of the risks of using "medical marijuana" in this regard. Copyright © 2016 by the National Comprehensive Cancer Network.

Role of capsaicin-sensitive nerves and tachykinins in mast cell tryptase-induced inflammation of murine knees.

PubMed

Borbély, Éva; Sándor, Katalin; Markovics, Adrienn; Kemény, Ágnes; Pintér, Erika; Szolcsányi, János; Quinn, John P; McDougall, Jason J; Helyes, Zsuzsanna

2016-09-01

Mast cell tryptase (MCT) is elevated in arthritic joints, but its direct effects are not known. Here, we investigated MCT-evoked acute inflammatory and nociceptive mechanisms with behavioural, in vivo imaging and immunological techniques. Neurogenic inflammation involving capsaicin-sensitive afferents, transient receptor potential vanilloid 1 receptor (TRPV1), substance P (SP), neurokinin A (NKA) and their NK1 tachykinin receptor were studied using gene-deleted mice compared to C57Bl/6 wildtypes (n = 5-8/group). MCT was administered intraarticularly or topically (20 μl, 12 μg/ml). Capsaicin-sensitive afferents were defunctionalized with the TRPV1 agonist resiniferatoxin (RTX; 30-70-100 μg/kg s.c. pretreatment). Knee diameter was measured with a caliper, synovial perfusion with laser Doppler imaging, mechanonociception with aesthesiometry and weight distribution with incapacitance tester over 6 h. Cytokines and neuropeptides were determined with immunoassays. MCT induced synovial vasodilatation, oedema, impaired weight distribution and mechanical hyperalgesia, but cytokine or neuropeptide levels were not altered at the 6-h timepoint. Hyperaemia was reduced in RTX-treated and TRPV1-deleted animals, and oedema was absent in NK1-deficient mice. Hyperalgesia was decreased in SP/NKA- and NK1-deficient mice, weight bearing impairment in RTX-pretreated, TRPV1- and NK1-deficient animals. MCT evokes synovial hyperaemia, oedema, hyperalgesia and spontaneous pain. Capsaicin-sensitive afferents and TRPV1 receptors are essential for vasodilatation, while tachykinins mediate oedema and pain.

N-arachidonoyl--serine is neuroprotective after traumatic brain injury by reducing apoptosis

PubMed Central

Cohen-Yeshurun, Ayelet; Trembovler, Victoria; Alexandrovich, Alexander; Ryberg, Erik; Greasley, Peter J; Mechoulam, Raphael; Shohami, Esther; Leker, Ronen R

2011-01-01

N-arachidonoyl--serine (AraS) is a brain component structurally related to the endocannabinoid family. We investigated the neuroprotective effects of AraS following closed head injury induced by weight drop onto the exposed fronto-parietal skull and the mechanisms involved. A single injection of AraS following injury led to a significant improvement in functional outcome, and to reduced edema and lesion volume compared with vehicle. Specific antagonists to CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) or large conductance calcium-activated potassium (BK) channels reversed these effects. Specific binding assays did not indicate binding of AraS to the GPR55 cannabinoid receptor. N-arachidonoyl--serine blocked the attenuation in phosphorylated extracellular-signal-regulated kinase 1/2 (ERK) levels and led to an increase in pAkt in both the ipsilateral and contralateral cortices. Increased levels of the prosurvival factor Bcl-xL were evident 24 hours after injury in AraS-treated mice, followed by a 30% reduction in caspase-3 activity, measured 3 days after injury. Treatment with a CB2 antagonist, but not with a CB1 antagonist, reversed this effect. Our results suggest that administration of AraS leads to neuroprotection via ERK and Akt phosphorylation and induction of their downstream antiapoptotic pathways. These protective effects are related mostly to indirect signaling via the CB2R and TRPV1 channels but not through CB1 or GPR55 receptors. PMID:21505478

N-arachidonoyl-L-serine is neuroprotective after traumatic brain injury by reducing apoptosis.

PubMed

Cohen-Yeshurun, Ayelet; Trembovler, Victoria; Alexandrovich, Alexander; Ryberg, Erik; Greasley, Peter J; Mechoulam, Raphael; Shohami, Esther; Leker, Ronen R

2011-08-01

N-arachidonoyl-L-serine (AraS) is a brain component structurally related to the endocannabinoid family. We investigated the neuroprotective effects of AraS following closed head injury induced by weight drop onto the exposed fronto-parietal skull and the mechanisms involved. A single injection of AraS following injury led to a significant improvement in functional outcome, and to reduced edema and lesion volume compared with vehicle. Specific antagonists to CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) or large conductance calcium-activated potassium (BK) channels reversed these effects. Specific binding assays did not indicate binding of AraS to the GPR55 cannabinoid receptor. N-arachidonoyl-L-serine blocked the attenuation in phosphorylated extracellular-signal-regulated kinase 1/2 (ERK) levels and led to an increase in pAkt in both the ipsilateral and contralateral cortices. Increased levels of the prosurvival factor Bcl-xL were evident 24 hours after injury in AraS-treated mice, followed by a 30% reduction in caspase-3 activity, measured 3 days after injury. Treatment with a CB2 antagonist, but not with a CB1 antagonist, reversed this effect. Our results suggest that administration of AraS leads to neuroprotection via ERK and Akt phosphorylation and induction of their downstream antiapoptotic pathways. These protective effects are related mostly to indirect signaling via the CB2R and TRPV1 channels but not through CB1 or GPR55 receptors.