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Sample records for receptor content induced

  1. Stimulation of high affinity gamma-aminobutyric acidB receptors potentiates the depolarization-induced increase of intraneuronal ionized calcium content in cerebellar granule neurons.

    PubMed

    De Erausquin, G; Brooker, G; Costa, E; Wojcik, W J

    1992-09-01

    In the treatment of spasticity, the therapeutic cerebrospinal fluid levels of (+/-)-baclofen, a gamma-aminobutyric acid (GABA)B receptor agonist, are below 1 microM. However, the mechanism of the therapeutic action of (+/-)-baclofen remains unknown, because, for the most part, the action of (+/-)-baclofen on GABAB receptors requires micromolar concentrations. Using fura-2 fluorescence microscopy, intracellular ionized calcium was measured in cerebellar granule neurons. Stimulation of a high affinity GABAB receptor potentiated by 2-3-fold the rise in intracellular calcium observed after depolarization of the cell with a Krebs Ringer's buffered solution containing 40 mM K+. Both GABA (100 nM) and (+/-)-baclofen (10-100 nM) stimulated this high affinity receptor. The potentiation of the depolarization-induced rise in intracellular calcium by (+/-)-baclofen (100 nM) was completely blocked by the GABAB receptor antagonist CGP 35348 (200 microM). Also, the intracellular calcium response induced by the activation of high affinity GABAB receptors was prevented by dantrolene (10 microM). The cerebellar granule neurons contained calcium-induced calcium release (CICR) stores. Caffeine (3 mM) and ryanodine (100 microM) potentiated the depolarization-induced rise in intracellular calcium, and this response to both drugs was blocked by dantrolene (10 microM). Because dantrolene does not prevent the rise in intracellular calcium after cell depolarization (this calcium originated from the influx of extracellular calcium), (+/-)-baclofen acting via the high affinity GABAB receptor indirectly activates the CICR stores, allowing the influx of extracellular calcium to trigger the release of calcium from these dantrolene-sensitive CICR stores. Thus, this high affinity GABAB receptor might become activated during persistent depolarization caused by pathological states and could be a mechanism to be studied for the therapeutic action of (+/-)-baclofen in spasticity.

  2. A high-content EMT screen identifies multiple receptor tyrosine kinase inhibitors with activity on TGFβ receptor.

    PubMed

    Lotz-Jenne, Carina; Lüthi, Urs; Ackerknecht, Sabine; Lehembre, François; Fink, Tobias; Stritt, Manuel; Wirth, Matthias; Pavan, Simona; Bill, Ruben; Regenass, Urs; Christofori, Gerhard; Meyer-Schaller, Nathalie

    2016-05-03

    An epithelial to mesenchymal transition (EMT) enables epithelial tumor cells to break out of the primary tumor mass and to metastasize. Understanding the molecular mechanisms driving EMT in more detail will provide important tools to interfere with the metastatic process. To identify pharmacological modulators and druggable targets of EMT, we have established a novel multi-parameter, high-content, microscopy-based assay and screened chemical compounds with activities against known targets. Out of 3423 compounds, we have identified 19 drugs that block transforming growth factor beta (TGFβ)-induced EMT in normal murine mammary gland epithelial cells (NMuMG). The active compounds include inhibitors against TGFβ receptors (TGFBR), Rho-associated protein kinases (ROCK), myosin II, SRC kinase and uridine analogues. Among the EMT-repressing compounds, we identified a group of inhibitors targeting multiple receptor tyrosine kinases, and biochemical profiling of these multi-kinase inhibitors reveals TGFBR as a thus far unknown target of their inhibitory spectrum. These findings demonstrate the feasibility of a multi-parameter, high-content microscopy screen to identify modulators and druggable targets of EMT. Moreover, the newly discovered "off-target" effects of several receptor tyrosine kinase inhibitors have important consequences for in vitro and in vivo studies and might beneficially contribute to the therapeutic effects observed in vivo.

  3. OXYTOCIN INDUCES SOCIAL COMMUNICATION BY ACTIVATING ARGININEVASOPRESSIN V1A RECEPTORS AND NOT OXYTOCIN RECEPTORS

    PubMed Central

    SONG, Zhimin; MCCANN, Katharine E.; MCNEILL, John K.; LARKIN, Tony E.; HUHMAN, Kim L.; ALBERS, H. Elliott

    2014-01-01

    Arginine-vasopressin (AVP) and oxytocin (OT) and their receptors are very similar in structure. As a result, at least some of the effects of these peptides may be the result of crosstalk between their canonical receptors. The present study investigated this hypothesis by determining whether the induction of flank marking, a form of social communication in Syrian hamsters, by OT is mediated by the OT receptor or the AVP V1a receptor. Intracerebroventricular (ICV) injections of OT or AVP induced flank marking in a dose-dependent manner although the effects of AVP were approximately 100 times greater than those of OT. Injections of highly selective V1a receptor agonists but not OT receptor agonists induced flank marking, and V1a receptor antagonists but not OT receptor antagonists significantly inhibited the ability of OT to induce flank marking. Lastly, injection of alpha-melanocyte-stimulating hormone (α-MSH), a peptide that stimulates OT but not AVP release, significantly increased odor-induced flank marking, and these effects were blocked by a V1a receptor antagonist. These data demonstrate that OT induces flank marking by activating AVP V1a and not OT receptors, suggesting that the V1a receptor should be considered to be an OT receptor as well as an AVP receptor. PMID:25173438

  4. Elevated glucose concentration changes the content and cellular localization of AMPA receptors in the retina but not in the hippocampus.

    PubMed

    Castilho, A F; Liberal, J T; Baptista, F I; Gaspar, J M; Carvalho, A L; Ambrósio, A F

    2012-09-06

    Diabetic retinopathy and diabetic encephalopathy are two common complications of diabetes mellitus. The impairment of glutamatergic neurotransmission in the retina and hippocampus has been suggested to be involved in the pathogenesis of these diabetic complications. In this study, we investigated the effect of elevated glucose concentration and diabetes on the protein content and surface expression of AMPA receptor subunits in the rat retina and hippocampus. We have used two models, cultured retinal and hippocampal cells exposed to elevated glucose concentration and an animal model of streptozotocin-induced type 1 diabetes. The immunoreactivity of GluA1, GluA2 and GluA4 was evaluated by Western blot and immunocytochemistry. The levels of these subunits at the plasma membrane were evaluated by biotinylation and purification of plasma membrane-associated proteins. Elevated glucose concentration increased the total levels of GluA2 subunit of AMPA receptors in retinal neural cells, but not of the subunits GluA1 or GluA4. However, at the plasma membrane, elevated glucose concentration induced an increase of all AMPA receptor subunits. In cultured hippocampal neurons, elevated glucose concentration did not induce significant alterations in the levels of AMPA receptor subunits. In the retinas of diabetic rats there were no persistent changes in the levels of AMPA receptor subunits comparing to aged-matched control retinas. Also, no consistent changes were detected in the levels of GluA1, GluA2 or GluA4 in the hippocampus of diabetic rats. We demonstrate that elevated glucose concentration induces early changes in AMPA receptor subunits, mainly in GluA2 subunit, in retinal neural cells. Conversely, hippocampal neurons seem to remain unaffected by elevated glucose concentration, concerning the expression of AMPA receptors, suggesting that AMPA receptors are more susceptible to the stress caused by elevated glucose concentration in retinal cells than in hippocampal neurons.

  5. Changes in acetylcholine content, release and muscarinic receptors in rat hippocampus under cold stress

    SciTech Connect

    Fatranska, M.; Budai, D.; Gulya, K; Kvetnansky, R.

    1989-01-01

    The aim was to study the mechanism of the previously established decrease in acetylcholine (ACh) concentration in the rat hippocampus under cold stress. Male rats were exposed for 14 days to cold (5/degree/C) or kept (controls) at room temperature (24/degree/C). Acetylcholine content, release and muscarinic receptor binding were investigated in the hippocampus. Cold exposure resulted in a decrease of ACh concentration in the dorsal hippocampus. Moreover, the potassium-evoked release of ACh from hippocampal slices was increased and an increase of maximal binding capacity of (/sup 3/H)(-) quinuclidinyl benzilate in the dorsal hippocampus of cold exposed animals was also observed. Thus the decrease of hippocampal ACh concentration under cold exposure is probably due to its increased release. On balance then, our results demonstrate that cold stress in the rat induces significant activation of the hippocampal cholinergic system.

  6. Hydrogen peroxide down-regulates inositol 1,4,5-trisphosphate receptor content through proteasome activation.

    PubMed

    Martín-Garrido, A; Boyano-Adánez, M C; Alique, M; Calleros, L; Serrano, I; Griera, M; Rodríguez-Puyol, D; Griendling, K K; Rodríguez-Puyol, M

    2009-11-15

    Hydrogen peroxide (H(2)O(2)) is implicated in the regulation of signaling pathways leading to changes in vascular smooth muscle function. Contractile effects produced by H(2)O(2) are due to the phosphorylation of myosin light chain kinase triggered by increases in intracellular calcium (Ca(2+)) from intracellular stores or influx of extracellular Ca(2+). One mechanism for mobilizing such stores involves the phosphoinositide pathway. Inositol 1,4,5-trisphosphate (IP(3)) mobilizes intracellular Ca(2+) by binding to a family of receptors (IP(3)Rs) on the endoplasmic-sarcoplasmic reticulum that act as ligand-gated Ca(2+) channels. IP(3)Rs can be rapidly ubiquitinated and degraded by the proteasome, causing a decrease in cellular IP(3)R content. In this study we show that IP(3)R(1) and IP(3)R(3) are down-regulated when vascular smooth muscle cells (VSMC) are stimulated by H(2)O(2), through an increase in proteasome activity. Moreover, we demonstrate that the decrease in IP(3)R by H(2)O(2) is accompanied by a reduction in calcium efflux induced by IP(3) in VSMC. Also, we observed that angiotensin II (ANGII) induces a decrease in IP(3)R by activation of NADPH oxidase and that preincubation with H(2)O(2) decreases ANGII-mediated calcium efflux and planar cell surface area in VSMC. The decreased IP(3) receptor content observed in cells was also found in aortic rings, which exhibited a decreased ANGII-dependent contraction after treatment with H(2)O(2). Altogether, these results suggest that H(2)O(2) mediates IP(3)R down-regulation via proteasome activity.

  7. Muscarinic M1 receptor and cannabinoid CB1 receptor do not modulate paraoxon-induced seizures

    PubMed Central

    Kow, Rebecca L; Cheng, Eugene M; Jiang, Kelly; Le, Joshua H; Stella, Nephi; Nathanson, Neil M

    2015-01-01

    One of the major signs of severe organophosphate poisoning is seizures. Previous studies have shown that both muscarinic agonist- and organophosphate-induced seizures require activation of muscarinic acetylcholine receptors in the central nervous system. Seizures induced by the muscarinic agonist pilocarpine require the M1 receptor and are modulated by cannabinoid CB1 receptors. In this study, we determined whether M1 and CB1 receptors also regulated seizures induced by the organophosphate paraoxon. We found no differences in seizures induced by paraoxon in wild-type (WT) and M1 knockout (KO) mice, indicating that in contrast to pilocarpine seizures, M1 receptors are not required for paraoxon seizures. Furthermore, we found that pilocarpine administration resulted in seizure-independent activation of ERK in the hippocampus in a M1 receptor-dependent manner, while paraoxon did not induce seizure-independent activation of ERK in the mouse hippocampus. This shows that pilocarpine and paraoxon activated M1 receptors in the hippocampus to different extents. There were no differences in seizures induced by paraoxon in WT and CB1 KO mice, and neither CB1 agonist nor antagonist administration had significant effects on paraoxon seizures, indicating that, in contrast to pilocarpine seizures, paraoxon seizures are not modulated by CB1 receptors. These results demonstrate that there are fundamental molecular differences in the regulation of seizures induced by pilocarpine and paraoxon. PMID:25692018

  8. Intrarenal dopamine D1-like receptor stimulation induces natriuresis via an angiotensin type-2 receptor mechanism.

    PubMed

    Salomone, Leslie J; Howell, Nancy L; McGrath, Helen E; Kemp, Brandon A; Keller, Susanna R; Gildea, John J; Felder, Robin A; Carey, Robert M

    2007-01-01

    We explored the effects of direct renal interstitial stimulation of dopamine D(1)-like receptors with fenoldopam, a selective D(1)-like receptor agonist, on renal sodium excretion and angiotensin type-2 (AT(2)) receptor expression and cellular distribution in rats on a high-sodium intake. In contrast to vehicle-infused rats, sodium excretion increased in fenoldopam-infused rats during each of three 1-hour experimental periods (<0.001). Blood pressure was unaffected by vehicle or fenoldopam. In plasma membranes of renal cortical cells, fenoldopam increased D(1) receptor expression by 38% (P<0.05) and AT(2) receptor expression by 69% (P<0.01). In plasma membranes of renal proximal tubule cells, fenoldopam increased AT(2) receptor expression by 108% (P<0.01). In outer apical membranes of proximal tubule cells, fenoldopam increased AT(2) receptor expression by 59% (P<0.01). No significant change in total AT(2) receptor protein expression was detectable in response to fenoldopam. Fenoldopam-induced natriuresis was abolished when either PD-123319, a specific AT(2) receptor antagonist, or SCH-23390, a potent D(1)-like receptor antagonist, was coinfused with F (P<0.001). In summary, direct renal D(1)-like receptor activation increased urinary sodium excretion and the plasma membrane expression of AT(2) receptors in renal cortical and proximal tubule cells. D(1)-like receptor-induced natriuresis was abolished by intrarenal AT(2) receptor inhibition. These findings suggest that dopaminergic regulation of sodium excretion involves recruitment of AT(2) receptors to the outer plasma membranes of renal proximal tubule cells and that dopamine-induced natriuresis requires AT(2) receptor activation.

  9. Modulation of Pilocarpine-Induced Seizures by Cannabinoid Receptor 1

    PubMed Central

    Kow, Rebecca L.; Jiang, Kelly; Naydenov, Alipi V.; Le, Joshua H.; Stella, Nephi; Nathanson, Neil M.

    2014-01-01

    Administration of the muscarinic agonist pilocarpine is commonly used to induce seizures in rodents for the study of epilepsy. Activation of muscarinic receptors has been previously shown to increase the production of endocannabinoids in the brain. Endocannabinoids act at the cannabinoid CB1 receptors to reduce neurotransmitter release and the severity of seizures in several models of epilepsy. In this study, we determined the effect of CB1 receptor activity on the induction in mice of seizures by pilocarpine. We found that decreased activation of the CB1 receptor, either through genetic deletion of the receptor or treatment with a CB1 antagonist, increased pilocarpine seizure severity without modifying seizure-induced cell proliferation and cell death. These results indicate that endocannabinoids act at the CB1 receptor to modulate the severity of pilocarpine-induced seizures. Administration of a CB1 agonist produced characteristic CB1-dependent behavioral responses, but did not affect pilocarpine seizure severity. A possible explanation for the lack of effect of CB1 agonist administration on pilocarpine seizures, despite the effects of CB1 antagonist administration and CB1 gene deletion, is that muscarinic receptor-stimulated endocannabinoid production is acting maximally at CB1 receptors to modulate sensitivity to pilocarpine seizures. PMID:24752144

  10. Relationship between oestrogen-receptor content and histological grade in human primary breast tumours.

    PubMed Central

    Maynard, P. V.; Davies, C. J.; Blamey, R. W.; Elston, C. W.; Johnson, J.; Griffiths, K.

    1978-01-01

    A series of 300 patients presenting consecutively with primary operable breast cancer has been studied. A significant correlation was found between oestrogen-receptor (ER) content and histological grade: the better-differentiated tumours rarely lacked receptor. This correlation was significant only in women defined as post-menopausal. Data on early recurrence of disease indicate a worse prognosis for women in whom primary tumours are ER-. PMID:743491

  11. Non-NMDA receptor antagonist-induced drinking in rat

    NASA Technical Reports Server (NTRS)

    Xu, Z.; Johnson, A. K.

    1998-01-01

    Glutamate has been implicated in the central control of mechanisms that maintain body fluid homeostasis. The present studies demonstrate that intracerebroventricular (i.c.v.) injections of the non-N-methyl-d-aspartate (NMDA) receptor antagonists 6, 7-dinitroquinoxaline-2,3-dione (DNQX) and 6-cyano-7-nitroquinoxaline-2,3 dione (CNQX) induce drinking in rats. The dipsogenic effect of i.c.v. DNQX was antagonized by the non-NMDA receptor agonist alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). The water intake induced by DNQX was also blocked by pretreatment with a NMDA receptor antagonist, MK-801, but not by angiotensin type 1 (AT1) or acetylcholine muscarinic receptor antagonists (losartan and atropine). The results indicate that non-NMDA receptors may exert a tonic inhibitory effect within brain circuits that control dipsogenic activity and that functional integrity of NMDA receptors may be required for the non-NMDA receptor antagonists to induce water intake. Copyright 1998 Published by Elsevier Science B.V.

  12. Ursodeoxycholic Acid Induces Death Receptor-mediated Apoptosis in Prostate Cancer Cells

    PubMed Central

    Lee, Won Sup; Jung, Ji Hyun; Panchanathan, Radha; Yun, Jeong Won; Kim, Dong Hoon; Kim, Hye Jung; Kim, Gon Sup; Ryu, Chung Ho; Shin, Sung Chul; Hong, Soon Chan; Choi, Yung Hyun; Jung, Jin-Myung

    2017-01-01

    Background Bile acids have anti-cancer properties in a certain types of cancers. We determined anticancer activity and its underlying molecular mechanism of ursodeoxycholic acid (UDCA) in human DU145 prostate cancer cells. Methods Cell viability was measured with an MTT assay. UDCA-induced apoptosis was determined with flow cytometric analysis. The expression levels of apoptosis-related signaling proteins were examined with Western blotting. Results UDCA treatment significantly inhibited cell growth of DU145 in a dose-dependent manner. It induced cellular shrinkage and cytoplasmic blebs and accumulated the cells with sub-G1 DNA contents. Moreover, UDCA activated caspase 8, suggesting that UDCA-induced apoptosis is associated with extrinsic pathway. Consistent to this finding, UDCA increased the expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, death receptor 4 (DR4) and death receptor 5 (DR5), and TRAIL augmented the UDCA-induced cell death in DU145 cells. In addition, UDCA also increased the expressions of Bax and cytochrome c and decreased the expression of Bcl-xL in DU145 cells. This finding suggests that UDCA-induced apoptosis may be involved in intrinsic pathway. Conclusions UDCA induces apoptosis via extrinsic pathway as well as intrinsic pathway in DU145 prostate cancer cells. UDCA may be a promising anti-cancer agent against prostate cancer. PMID:28382282

  13. Radiation-induced DNA content variability in mouse sperm

    SciTech Connect

    Pinkel, D.; Gledhill, B.L.; van Dilla, M.A.; Lake, S.; Wyrobek, A.J.

    1983-09-01

    Mouse sperm collected from the cauda epididymidis 35 days after acute testicular x-ray exposure and fluorescently stained for DNA show dose-dependent increases in the coefficient of variation (CV) of flow cytometrically obtained fluorescence distributions. By comparing dose-response curves obtained with three protocols which overcome the optical and cytochemical difficulties of sperm measurement in different ways we conclude the response is due to x-ray-induced DNA content variability. Computer modeling of the shapes of the fluorescence distributions show that at 600 rad 30 to 40% of the sperm have abnormal DNA content. Some have errors as large as two whole chromosomes, but it is not clear whether they are due to whole chromosome nondisjunction or a finer fragmentation of the genome. Exposures to benzo(a)pyrene and mitomycin C cause no detectable DNA content variability. We conclude mouse sperm DNA content measurements are not sensitive to small amounts of aneuploidy and as such will only be useful in detecting agents that produce substantial DNA content variability. Another animal with a smaller number of chromosomes might be more favorable. These sperm measurement techniques may find additional application in other areas of reproductive biology, such as the determination of the relative numbers of X and Y chromosome-bearing sperm in semen that may be artifically enriched in one population.

  14. Mechanism of GABAB receptor-induced BDNF secretion and promotion of GABAA receptor membrane expression.

    PubMed

    Kuczewski, Nicola; Fuchs, Celine; Ferrand, Nadine; Jovanovic, Jasmina N; Gaiarsa, Jean-Luc; Porcher, Christophe

    2011-08-01

    Recent studies have shown that GABA(B) receptors play more than a classical inhibitory role and can function as an important synaptic maturation signal early in life. In a previous study, we reported that GABA(B) receptor activation triggers secretion of brain-derived neurotrophic factor (BDNF) and promotes the functional maturation of GABAergic synapses in the developing rat hippocampus. To identify the signalling pathway linking GABA(B) receptor activation to BDNF secretion in these cells, we have now used the phosphorylated form of the cAMP response element-binding protein as a biological sensor for endogenous BDNF release. In the present study, we show that GABA(B) receptor-induced secretion of BDNF relies on the activation of phospholipase C, followed by the formation of diacylglycerol, activation of protein kinase C, and the opening of L-type voltage-dependent Ca(2+) channels. We further show that once released by GABA(B) receptor activation, BDNF increases the membrane expression of β(2/3) -containing GABA(A) receptors in neuronal cultures. These results reveal a novel function of GABA(B) receptors in regulating the expression of GABA(A) receptor through BDNF-tropomyosin-related kinase B receptor dependent signalling pathway.

  15. Acute isoproterenol induces anxiety-like behavior in rats and increases plasma content of extracellular vesicles.

    PubMed

    Leo, Giuseppina; Guescini, Michele; Genedani, Susanna; Stocchi, Vilberto; Carone, Chiara; Filaferro, Monica; Sisti, Davide; Marcoli, Manuela; Maura, Guido; Cortelli, Pietro; Guidolin, Diego; Fuxe, Kjell; Agnati, Luigi Francesco

    2015-04-01

    Several clinical observations have demonstrated a link between heart rate and anxiety or panic disorders. In these patients, β-adrenergic receptor function was altered. This prompted us to investigate whether the β-adrenergic receptor agonist isoproterenol, at a dose that stimulates peripheral β-adrenergic system but has no effects at the central nervous system, can induce anxiety-like behavior in rats. Moreover, some possible messengers involved in the peripheral to brain communication were investigated. Our results showed that isoproterenol (5 mg kg(-1) i.p.) increased heart rate, evoked anxiety-like behavior, did not result in motor impairments and increased extracellular vesicle content in the blood. Plasma corticosterone level was unmodified as well as vesicular Hsp70 content. Vesicular miR-208 was also unmodified indicating a source of increased extracellular vesicles different from cardiomyocytes. We can hypothesize that peripheral extracellular vesicles might contribute to the β-adrenergic receptor-evoked anxiety-like behavior, acting as peripheral signals in modulating the mental state.

  16. Radiation-induced DNA content variability in mouse sperm

    SciTech Connect

    Pinkel, D.; Gledhill, B.L.; Van Dilla, M.A.; Lake, S.; Wyrobek, A.J.

    1983-09-01

    Mouse sperm collected from the cauda epididymidis 35 days after acute testicular X-ray exposure and fluorescently stained for DNA show dose-dependent increases in the coefficient of variation (CV) of flow cytometrically obtained fluorescence distributions. By comparing dose-response curves obtained with three protocols which overcome the optical and cytochemical difficulties of sperm measurement in different ways we conclude the response is due to X-ray-induced DNA content variability. In the range between 0 and 600 rad the dose dependence of the square of CV of the DNA content variability, delta CV2D, is described by delta CV2D . Bx + Cx2, with 0 less than or equal to B less than or equal to 0.23 X 10(-2) and C . (0.44 +/- 0.06) X 10(-4). The dose x is measured in rad and delta CVD is expressed in percent. Computer modeling of the shapes of the fluorescence distributions show that at 600 rad 30 to 40% of the sperm have abnormal DNA content. Some have errors as large as two whole chromosomes, but it is not clear whether they are due to whole chromosome nondisjunction or a finer fragmentation of the genome. Exposures to benzo(a)pyrene and mitomycin C cause no detectable DNA content variability. We conclude mouse sperm DNA content measurements are not sensitive to small amounts of aneuploidy and as such will only be useful in detecting agents that produce substantial DNA content variability. Another animal with a smaller number of chromosomes might be more favorable. These sperm measurement techniques may find additional application in other areas of reproductive biology, such as the determination of the relative numbers of X and Y chromosome-bearing sperm in semen that may be artificially enriched in one population.

  17. Amyloid-β-Induced Dysregulation of AMPA Receptor Trafficking

    PubMed Central

    Guntupalli, Sumasri; Widagdo, Jocelyn; Anggono, Victor

    2016-01-01

    Evidence from neuropathological, genetic, animal model, and biochemical studies has indicated that the accumulation of amyloid-beta (Aβ) is associated with, and probably induces, profound neuronal changes in brain regions critical for memory and cognition in the development of Alzheimer's disease (AD). There is considerable evidence that synapses are particularly vulnerable to AD, establishing synaptic dysfunction as one of the earliest events in pathogenesis, prior to neuronal loss. It is clear that excessive Aβ levels can disrupt excitatory synaptic transmission and plasticity, mainly due to dysregulation of the AMPA and NMDA glutamate receptors in the brain. Importantly, AMPA receptors are the principal glutamate receptors that mediate fast excitatory neurotransmission. This is essential for synaptic plasticity, a cellular correlate of learning and memory, which are the cognitive functions that are most disrupted in AD. Here we review recent advances in the field and provide insights into the molecular mechanisms that underlie Aβ-induced dysfunction of AMPA receptor trafficking. This review focuses primarily on NMDA receptor- and metabotropic glutamate receptor-mediated signaling. In particular, we highlight several mechanisms that underlie synaptic long-term depression as common signaling pathways that are hijacked by the neurotoxic effects of Aβ. PMID:27073700

  18. Primary Macrophage Chemotaxis Induced by Cannabinoid Receptor 2 Agonists Occurs Independently of the CB2 Receptor.

    PubMed

    Taylor, Lewis; Christou, Ivy; Kapellos, Theodore S; Buchan, Alice; Brodermann, Maximillian H; Gianella-Borradori, Matteo; Russell, Angela; Iqbal, Asif J; Greaves, David R

    2015-06-02

    Activation of CB2 has been demonstrated to induce directed immune cell migration. However, the ability of CB2 to act as a chemoattractant receptor in macrophages remains largely unexplored. Using a real-time chemotaxis assay and a panel of chemically diverse and widely used CB2 agonists, we set out to examine whether CB2 modulates primary murine macrophage chemotaxis. We report that of 12 agonists tested, only JWH133, HU308, L-759,656 and L-759,633 acted as macrophage chemoattractants. Surprisingly, neither pharmacological inhibition nor genetic ablation of CB2 had any effect on CB2 agonist-induced macrophage chemotaxis. As chemotaxis was pertussis toxin sensitive in both WT and CB2(-/-) macrophages, we concluded that a non-CB1/CB2, Gi/o-coupled GPCR must be responsible for CB2 agonist-induced macrophage migration. The obvious candidate receptors GPR18 and GPR55 could not mediate JWH133 or HU308-induced cytoskeletal rearrangement or JWH133-induced β-arrestin recruitment in cells transfected with either receptor, demonstrating that neither are the unidentified GPCR. Taken together our results conclusively demonstrate that CB2 is not a chemoattractant receptor for murine macrophages. Furthermore we show for the first time that JWH133, HU308, L-759,656 and L-759,633 have off-target effects of functional consequence in primary cells and we believe that our findings have wide ranging implications for the entire cannabinoid field.

  19. Primary Macrophage Chemotaxis Induced by Cannabinoid Receptor 2 Agonists Occurs Independently of the CB2 Receptor

    PubMed Central

    Taylor, Lewis; Christou, Ivy; Kapellos, Theodore S.; Buchan, Alice; Brodermann, Maximillian H.; Gianella-Borradori, Matteo; Russell, Angela; Iqbal, Asif J.; Greaves, David R.

    2015-01-01

    Activation of CB2 has been demonstrated to induce directed immune cell migration. However, the ability of CB2 to act as a chemoattractant receptor in macrophages remains largely unexplored. Using a real-time chemotaxis assay and a panel of chemically diverse and widely used CB2 agonists, we set out to examine whether CB2 modulates primary murine macrophage chemotaxis. We report that of 12 agonists tested, only JWH133, HU308, L-759,656 and L-759,633 acted as macrophage chemoattractants. Surprisingly, neither pharmacological inhibition nor genetic ablation of CB2 had any effect on CB2 agonist-induced macrophage chemotaxis. As chemotaxis was pertussis toxin sensitive in both WT and CB2-/- macrophages, we concluded that a non-CB1/CB2, Gi/o-coupled GPCR must be responsible for CB2 agonist-induced macrophage migration. The obvious candidate receptors GPR18 and GPR55 could not mediate JWH133 or HU308-induced cytoskeletal rearrangement or JWH133-induced β-arrestin recruitment in cells transfected with either receptor, demonstrating that neither are the unidentified GPCR. Taken together our results conclusively demonstrate that CB2 is not a chemoattractant receptor for murine macrophages. Furthermore we show for the first time that JWH133, HU308, L-759,656 and L-759,633 have off-target effects of functional consequence in primary cells and we believe that our findings have wide ranging implications for the entire cannabinoid field. PMID:26033291

  20. Dopamine D(3) receptors contribute to methamphetamine-induced alterations in dopaminergic neuronal function: role of hyperthermia.

    PubMed

    Baladi, Michelle G; Newman, Amy H; Nielsen, Shannon M; Hanson, Glen R; Fleckenstein, Annette E

    2014-06-05

    Methamphetamine administration causes long-term deficits to dopaminergic systems that, in humans, are thought to be associated with motor slowing and memory impairment. Methamphetamine interacts with the dopamine transporter (DAT) and increases extracellular concentrations of dopamine that, in turn, binds to a number of dopamine receptor subtypes. Although the relative contribution of each receptor subtype to the effects of methamphetamine is not fully known, non-selective dopamine D2/D3 receptor antagonists can attenuate methamphetamine-induced changes to dopamine systems. The present study extended these findings by testing the role of the dopamine D3 receptor subtype in mediating the long-term dopaminergic, and for comparison serotonergic, deficits caused by methamphetamine. Results indicate that the dopamine D3 receptor selective antagonist, PG01037, attenuated methamphetamine-induced decreases in striatal DAT, but not hippocampal serotonin (5HT) transporter (SERT), function, as assessed 7 days after treatment. However, PG01037 also attenuated methamphetamine-induced hyperthermia. When methamphetamine-induced hyperthermia was maintained by treating rats in a warm ambient environment, PG01037 failed to attenuate the effects of methamphetamine on DAT uptake. Furthermore, PG01037 did not attenuate methamphetamine-induced decreases in dopamine and 5HT content. Taken together, the present study demonstrates that dopamine D3 receptors mediate, in part, the long-term deficits in DAT function caused by methamphetamine, and that this effect likely involves an attenuation of methamphetamine-induced hyperthermia.

  1. TRPA1 receptors mediate environmental irritant-induced meningeal vasodilatation

    PubMed Central

    Kunkler, Phillip Edward; Ballard, Carrie Jo; Oxford, Gerry Stephen; Hurley, Joyce Harts

    2010-01-01

    The TRPA1 receptor is a member of the transient receptor potential (TRP) family of ion channels expressed in nociceptive neurons. TRPA1 receptors are targeted by pungent compounds from mustard and garlic and environmental irritants such as formaldehyde and acrolein. Ingestion or inhalation of these chemical agents causes irritation and burning in the nasal and oral mucosa and respiratory lining. Headaches have been widely reported to be induced by inhalation of environmental irritants, but it is unclear how these agents produce headache. Stimulation of trigeminal neurons releases CGRP and substance P and induces neurogenic inflammation associated with the pain of migraine. Here we test the hypothesis that activation of TRPA1 receptors are the mechanistic link between environmental irritants and peptide mediated neurogenic inflammation. Known TRPA1 agonists and environmental irritants stimulate CGRP release from dissociated rat trigeminal ganglia neurons and this release is blocked by a selective TRPA1 antagonist, HC-030031. Further, TRPA1 agonists and environmental irritants increase meningeal blood flow following intranasal administration. Prior dural application of the CGRP antagonist, CGRP8–37, or intranasal or dural administration of HC-030031, blocks the increases in blood flow elicited by environmental irritants. Together these results demonstrate that TRPA1 receptor activation by environmental irritants stimulates CGRP release and increases cerebral blood flow. We suggest that these events contribute to headache associated with environmental irritants. PMID:21075522

  2. The Dual Orexin Receptor Antagonist Almorexant Induces Sleep and Decreases Orexin-Induced Locomotion by Blocking Orexin 2 Receptors

    PubMed Central

    Mang, Géraldine M.; Dürst, Thomas; Bürki, Hugo; Imobersteg, Stefan; Abramowski, Dorothee; Schuepbach, Edi; Hoyer, Daniel; Fendt, Markus; Gee, Christine E.

    2012-01-01

    Study Objectives: Orexin peptides activate orexin 1 and orexin 2 receptors (OX1R and OX2R), regulate locomotion and sleep-wake. The dual OX1R/OX2R antagonist almorexant reduces activity and promotes sleep in multiple species, including man. The relative contributions of the two receptors in locomotion and sleep/wake regulation were investigated in mice. Design: Mice lacking orexin receptors were used to determine the contribution of OX1R and OX2R to orexin A-induced locomotion and to almorexant-induced sleep. Setting: N/A. Patients or Participants: C57BL/6J mice and OX1R+/+, OX1R-/-, OX2R+/+, OX2R-/- and OX1R-/-/OX2R-/- mice. Interventions: Intracerebroventricular orexin A; oral dosing of almorexant. Measurements and Results: Almorexant attenuated orexin A-induced locomotion. As in other species, almorexant dose-dependently increased rapid eye movement sleep (REM) and nonREM sleep in mice. Almorexant and orexin A were ineffective in OX1R-/-/OX2R-/- mice. Both orexin A-induced locomotion and sleep induction by almorexant were absent in OX2R-/- mice. Interestingly, almorexant did not induce cataplexy in wild-type mice under conditions where cataplexy was seen in mice lacking orexins and in OX1R-/-/OX2R-/- mice. Almorexant dissociates very slowly from OX2R as measured functionally and in radioligand binding. Under non equilibrium conditions in vitro, almorexant was a dual antagonist whereas at equilibrium, almorexant became OX2R selective. Conclusions: In vivo, almorexant specifically inhibits the actions of orexin A. The two known orexin receptors mediate sleep induction by almorexant and orexin A-induced locomotion. However, OX2R activation mediates locomotion induction by orexin A and antagonism of OX2R is sufficient to promote sleep in mice. Citation: Mang GM; Dürst T; Bürki H; Imobersteg S; Abramowski D; Schuepbach E; Hoyer D; Fendt M; Gee CE. The dual orexin receptor antagonist almorexant induces sleep and decreases orexin-induced locomotion by blocking orexin

  3. Upregulation of 5-HT2C receptors in hippocampus of pilocarpine-induced epileptic rats: antagonism by Bacopa monnieri.

    PubMed

    Krishnakumar, Amee; Nandhu, M S; Paulose, C S

    2009-10-01

    Emotional disturbances, depressive mood, anxiety, aggressive behavior, and memory impairment are the common psychiatric features associated with temporal lobe epilepsy (TLE). The present study was carried out to investigate the role of Bacopa monnieri extract in hippocampus of pilocarpine-induced temporal lobe epileptic rats through the 5-HT(2C) receptor in relation to depression. Our results showed upregulation of 5-HT(2C) receptors with a decreased affinity in hippocampus of pilocarpine-induced epileptic rats. Also, there was an increase in 5-HT(2C) gene expression and inositol triphosphate content in epileptic hippocampus. Carbamazepine and B. monnieri treatments reversed the alterations in 5-HT(2C) receptor binding, gene expression, and inositol triphosphate content in treated epileptic rats as compared to untreated epileptic rats. The forced swim test confirmed the depressive behavior pattern during epilepsy that was nearly completely reversed by B. monnieri treatment.

  4. A primer on cytokines: sources, receptors, effects, and inducers.

    PubMed Central

    Curfs, J H; Meis, J F; Hoogkamp-Korstanje, J A

    1997-01-01

    Protection against pathogens is a prerequisite for survival of most organisms. To cope with this continuous challenge, complex defense mechanisms have evolved. The construction, adaptation, and maintenance of these mechanisms are under control of an extensive network of regulatory proteins called cytokines. A great number of cytokines have been described over the last 2 decades. This review consists of an overview of cytokines that are involved in immune responses and describes some historical and general aspects as well as prospective clinical applications. Major biological effects together with information on cytokine receptors, producers, inducers, and biochemical and molecular characteristics are listed in tables. In addition, some basic information is given on cytokine receptor signal transduction. Finally, the recent discoveries of cytokine receptors functioning as coreceptors in the pathogenesis of human immunodeficiency virus are summarized. PMID:9336671

  5. Dark chocolate receptors: epicatechin-induced cardiac protection is dependent on δ-opioid receptor stimulation

    PubMed Central

    Panneerselvam, Mathivadhani; Tsutsumi, Yasuo M.; Bonds, Jacqueline A.; Horikawa, Yousuke T.; Saldana, Michelle; Dalton, Nancy D.; Head, Brian P.; Patel, Piyush M.; Roth, David M.

    2010-01-01

    Epicatechin, a flavonoid, is a well-known antioxidant linked to a variety of protective effects in both humans and animals. In particular, its role in protection against cardiovascular disease has been demonstrated by epidemiologic studies. Low-dose epicatechin, which does not have significant antioxidant activity, is also protective; however, the mechanism by which low-dose epicatechin induces this effect is unknown. Our laboratory tested the hypothesis that low-dose epicatechin mediates cardiac protection via opioid receptor activation. C57BL/6 mice were randomly assigned to 1 of 10 groups: control, epicatechin, naloxone (nonselective opioid receptor antagonist), epicatechin + naloxone, naltrindole (δ-specific opioid receptor antagonist), epicatechin + naltrindole, norbinaltorphimine (nor-BNI, κ-specific opioid receptor antagonist), epicatechin + nor-BNI, 5-hydroxydecanoic acid [5-HD, ATP-sensitive potassium channel antagonist], and epicatechin + 5-HD. Epicatechin (1 mg/kg) or other inhibitors (5 mg/kg) were administered by oral gavage or intraperitoneal injection, respectively, daily for 10 days. Mice were subjected to 30 min coronary artery occlusion followed by 2 h of reperfusion, and infarct size was determined via planimetry. Whole heart homogenates were assayed for downstream opioid receptor signaling targets. Infarct size was significantly reduced in epicatechin- and epicatechin + nor-BNI-treated mice compared with control mice. This protection was blocked by naloxone, naltrindole, and 5-HD. Epicatechin and epicatechin + nor-BNI increased the phosphorylation of Src, Akt, and IκBα, while simultaneously decreasing the expression of c-Jun NH2-terminal kinase and caspase-activated DNase. All signaling effects are consistent with opioid receptor stimulation and subsequent cardiac protection. Naloxone, naltrindole, and 5-HD attenuated these effects. In conclusion, epicatechin acts via opioid receptors and more specifically through the δ-opioid receptor to

  6. Amyloid beta oligomers induce impairment of neuronal insulin receptors.

    PubMed

    Zhao, Wei-Qin; De Felice, Fernanda G; Fernandez, Sara; Chen, Hui; Lambert, Mary P; Quon, Michael J; Krafft, Grant A; Klein, William L

    2008-01-01

    Recent studies have indicated an association between Alzheimer's disease (AD) and central nervous system (CNS) insulin resistance. However, the cellular mechanisms underlying the link between these two pathologies have not been elucidated. Here we show that signal transduction by neuronal insulin receptors (IR) is strikingly sensitive to disruption by soluble Abeta oligomers (also known as ADDLs). ADDLs are known to accumulate in AD brain and have recently been implicated as primary candidates for initiating deterioration of synapse function, composition, and structure. Using mature cultures of hippocampal neurons, a preferred model for studies of synaptic cell biology, we found that ADDLs caused a rapid and substantial loss of neuronal surface IRs specifically on dendrites bound by ADDLs. Removal of dendritic IRs was associated with increased receptor immunoreactivity in the cell body, indicating redistribution of the receptors. The neuronal response to insulin, measured by evoked IR tyrosine autophosphorylation, was greatly inhibited by ADDLs. Inhibition also was seen with added glutamate or potassium-induced depolarization. The effects on IR function were completely blocked by NMDA receptor antagonists, tetrodotoxin, and calcium chelator BAPTA-AM. Downstream from the IR, ADDLs induced a phosphorylation of Akt at serine473, a modification associated with neurodegenerative and insulin resistance diseases. These results identify novel factors that affect neuronal IR signaling and suggest that insulin resistance in AD brain is a response to ADDLs, which disrupt insulin signaling and may cause a brain-specific form of diabetes as part of an overall pathogenic impact on CNS synapses.

  7. Membrane and nuclear estrogen receptor α collaborate to suppress adipogenesis but not triglyceride content

    PubMed Central

    Pedram, Ali; Razandi, Mahnaz; Blumberg, Bruce; Levin, Ellis Robert

    2016-01-01

    Estrogen and estrogen receptor (ER)-α suppress visceral fat development through actions in several organs via unclear mechanisms that we sought to identify. Using mice that express only nuclear ER-α [nuclear-only ER-α (NOER) mice] or plasma membrane ER-α [membrane-only ER-α (MOER) mice], we found that 10-wk-old mice that lacked either receptor pool showed extensive abdominal visceral fat deposition and weight gain compared with wild-type (WT) mice. Differentiation of cultured bone marrow stem cells (BMSCs) into the adipocyte lineage was suppressed by 17-β-estradiol (E2) in WT female mice but not in NOER or MOER mice. This finding correlated with E2 inhibition of prominent differentiation genes in WT BMSCs. In contrast, triglyceride content in differentiated BMSCs or 3T3-L1 cells was suppressed as a result of membrane ER-α signaling through several kinases to inhibit carbohydrate response element–binding protein-α and -β. We concluded that extranuclear and nuclear ER-α collaborate to suppress adipocyte development, but inhibition of lipid synthesis in mature cells does not involve nuclear ER-α.—Pedram, A., Razandi, M., Blumberg, B., Levin, E. R. Membrane and nuclear estrogen receptor α collaborate to suppress adipogenesis but not triglyceride content. PMID:26373802

  8. Baclofen-induced antinociception and nicotinic receptor mechanism(s).

    PubMed

    Sabetkasai, M; Ahang, S; Shafaghi, B; Zarrindast, M R

    1999-11-01

    In this study, the influences of nicotinic receptor agents on baclofen-induced antinociception in the tail-flick test have been studied. Intraperitoneal administration of baclofen (2.5, 5 and 10 mg/kg) to mice induced a dose-dependent antinociception in the tail-flick test. Subcutaneous injection of nicotine (0.5-2.5 mg/kg) also caused a dose-dependent antinociceptive response. Intracerebral (10 and 20 microg/mouse) but not intraperitoneal administration of hexamethonium (5 and 10 mg/kg) to mice decreased the response of both nicotine and baclofen. However, administration of the GABA(B) antagonist CGP 35348 (100 and 200 mg/kg) decreased the response induced by baclofen but not by nicotine. It is concluded that at least part of the baclofen-induced antinociception may be mediated through a nicotinic mechanism.

  9. Thymic involution in the suspended rat - Adrenal hypertrophy and glucocorticoid receptor content

    NASA Technical Reports Server (NTRS)

    Steffen, J. M.; Musacchia, X. J.

    1986-01-01

    The relationship between thymic involution and adrenal hypertrophy is studied. The thymus, adrenal glands, and tissue water content are evaluated in male Sprague rats suspended in antiorthostatic (AO) or orthostatic (O) positions. A 50 percent decrease in the wet weight of the thymus and hypertrophy of the adrenal glands are observed during the seven days of AO suspension. After seven days of recovery the thymus weight is increased to control level; however, the hypertrophy of the adrenal glands remains unchanged. Thymic and renal responses in O postioned rats are similar to AO reactions. Thymic glucocorticoid (GC) receptor concentrations in the rats are analyzed; a 20 percent decrease in GC receptor site concentration, which is related to thymic involution, is detected in both AO and O rats. It is concluded that there is a temporal correlation between thymic involution and adrenal hypertrophy, which is not affected by AO positioning, and thymic involution is not associated with an increased sensitivity to GC.

  10. Vasoactive Intestinal Polypeptide and Muscarinic Receptors: Supersensitivity Induced by Long-Term Atropine Treatment

    NASA Astrophysics Data System (ADS)

    Hedlund, Britta; Abens, Janis; Bartfai, Tamas

    1983-04-01

    Long-term treatment of rats with atropine induced large increases in the numbers of muscarinic receptors and receptors for vasoactive intestinal polypeptide in the salivary glands. Since receptors for vasoactive intestinal polypeptide coexist with muscarinic receptors on the same neurons in this preparation, the results suggest that a drug that alters the sensitivity of one receptor may also affect the sensitivity of the receptor for a costored transmitter and in this way contribute to the therapeutic or side effects of the drug.

  11. Glomerular angiotensin II receptors in gentamicin-induced renal failure in the rat.

    PubMed

    Esquerro, E; Rivas-Cabãnero, L; López-Novoa, J M

    1995-11-01

    We evaluated the properties of glomerular angiotensin II receptors in renal glomeruli isolated from control rats and from rats with gentamicin-induced renal failure. There were no differences in the affinity of angiotensin II for its receptor between glomeruli from control and those from rats treated with gentamicin. Angiotensin II receptor density was lower in glomeruli from rats with renal failure than in those from control rats (985 +/- 71 in gentamicin treated rats vs. 1602 +/- 213 fmol/mg prot in controls). No significant differences were observed in renin activity in the supernatant from glomeruli isolated from control rats (3.74 +/- 0.29 ng angiotensin l/mL h) and those isolated from rats with gentamicin-induced renal failure (2.99 +/- 0.29 ng angiotensin l/mL h, p > 0.1). These findings do not support the contention of a role of angiotensin II in the development and maintenance of gentamicin-induced ARF.

  12. PET imaging of dopamine receptors in MPTP-induced parkinsonism

    SciTech Connect

    Larson, S.M.; DiChiro, G.; Burns, R.S.; Dannals, R.F.; Kopin, I.J.; Brooks, R.A.; Kessler, R.M.; Wagner, R.F.; Eckelman, W.C.; Margolin, R.A.

    1984-01-01

    MPTP(N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) induces parkinsonism in animals and man by selectively destroying dopaminergic neurons in the pars compacta of the substantia nigra. The postsynaptic neurons (and presumably the dopamine receptors) are intact. The authors have imaged dopamine receptors in a patient with MPTP induced parkinsonism, using /sup 11/CMS (3-N(/sup 11/C) methylspiperone. Seven and 9 mCi's, respectively, were injected at one week intervals while the patient was first off, and then on, L-dopa. As measured by NeuroPET (NIH), putamen to cerebellum concentration ratios rose progressively to 5.5:1, by 90 min. after injection. At this time the concentration of /sup 11/CMS was 10 picomole/cc (off L-dopa), and 14 picomole/cc (on L-dopa). The Duvoisin scale was used to assess the severity of the patient's parkinsonism immediately prior and at the end of PET imaging. On both occasions, despite the small mass amount of /sup 11/CMS injected, (1.1 g/kg), a transient worsening of symptoms was seen. The effect of L-Dopa was almost completely reversed by the /sup 11/CMS. In contrast, off L-Dopa the patients severe basal state was worsened only slightly. The PET scans suggested that dopamine receptors are not reduced in MPTP-induced parkinsonism. The findings were consistent with the hypotheses that PET may identify patients who will benefit from L-Dopa, and that expression of parkinsonian symptoms reflects desaturation of dopamine receptors in striatum.

  13. Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR.

    PubMed

    Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S; Liu, Qingsong; Zhang, Xin

    2016-01-01

    Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors.

  14. Mas receptor is involved in the estrogen-receptor induced nitric oxide-dependent vasorelaxation.

    PubMed

    Sobrino, Agua; Vallejo, Susana; Novella, Susana; Lázaro-Franco, Macarena; Mompeón, Ana; Bueno-Betí, Carlos; Walther, Thomas; Sánchez-Ferrer, Carlos; Peiró, Concepción; Hermenegildo, Carlos

    2017-04-01

    The Mas receptor is involved in the angiotensin (Ang)-(1-7) vasodilatory actions by increasing nitric oxide production (NO). We have previously demonstrated an increased production of Ang-(1-7) in human umbilical vein endothelial cells (HUVEC) exposed to estradiol (E2), suggesting a potential cross-talk between E2 and the Ang-(1-7)/Mas receptor axis. Here, we explored whether the vasoactive response and NO-related signalling exerted by E2 are influenced by Mas. HUVEC were exposed to 10nM E2 for 24h in the presence or absence of the selective Mas receptor antagonist A779, and the estrogen receptor (ER) antagonist ICI182780 (ICI). E2 increased Akt and endothelial nitric oxide synthase (eNOS) mRNA and protein expression, measured by RT-PCR and Western blot, respectively. Furthermore, E2 increased Akt activity (determined by the levels of phospho-Ser(473)) and eNOS activity (by the enhanced phosphorylation of Ser(1177), the activated form), resulting in increased NO production, which was measured by the fluorescence probe DAF-2-FM. These signalling events were dependent on ER and Mas receptor activation, since they were abolished in the presence of ICI or A779. In ex-vivo functional experiments performed with a small-vessel myograph in isolated mesenteric vessels from wild-type mice pre-contracted with noradrenaline, the relaxant response to physiological concentrations of E2 was blocked by ICI and A779, to the same extent to that obtained in the vessels isolated from Mas-deficient. In conclusion, E2 induces NO production and vasodilation through mechanisms that require Mas receptor activation.

  15. Chrysin induces hyperalgesia via the GABAA receptor in mice.

    PubMed

    Zhai, Kui; Hu, Li; Chen, Juan; Fu, Cai-Yun; Chen, Qiang

    2008-08-01

    Chrysin (5,7-dihydroxyflavone) is a natural flavone commonly found in many plants including PASSIFLORA COERULEA L. Researchers have performed extensive and detailed investigations on the behavioral and pharmacological effects of chrysin IN VIVO, but there was little information available on the effect of chrysin on nociception. Therefore, the present study was undertaken to investigate the effect of chrysin on the nociceptive threshold using the tail-immersion test. Intraperitoneal ( I. P.) injection of chrysin (10, 25, 50, 75, 100 mg/kg) dose- and time-dependently induced a pronounced decrease of the tail withdrawal latencies (TWL), thus characterizing a hyperalgesic effect (ED50 = 65.59 mg/kg). The following results showed that GABAA receptors were involved in the hyperalgesic effects of chrysin. 1) The hyperalgesia induced by chrysin was significantly and dose-dependently blocked by pretreatment with flumazenil (0.75, 1 mg/kg, I. P.), a specific antagonist for benzodiazepine sites associated with GABAA receptors. 2) Bicuculline (2, 4 mg/kg, I. P.), a GABAA receptor antagonist, markedly antagonized the hyperalgesic effect of chrysin in a dose-dependent manner. 3) Picrotoxin (2 mg/kg, I. P.), a chloride channel blocker, could also notably antagonize the hyperalgesia of chrysin. Oral administration of chrysin (75 mg/kg) also produced a hyperalgesic effect in the tail-immersion test. In addition, diazepam (1 mg/kg, I. P.) showed a marked antinociceptive effect, which was completely blocked by flumazenil (1 mg/kg, I. P.). In conclusion, it can be summarized that both I. P. and oral administration of chrysin produced a significant hyperalgesic effect in the tail-immersion test and that the hyperalgesic effect of chrysin may be associated with GABAA receptors.

  16. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    SciTech Connect

    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-03-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor.

  17. AMPA receptor potentiation can prevent ethanol-induced intoxication.

    PubMed

    Jones, Nicholas; Messenger, Marcus J; O'Neill, Michael J; Oldershaw, Anna; Gilmour, Gary; Simmons, Rosa M A; Iyengar, Smriti; Libri, Vincenzo; Tricklebank, Mark; Williams, Steve C R

    2008-06-01

    We present a substantial series of behavioral and imaging experiments, which demonstrate, for the first time, that increasing AMPA receptor-mediated neurotransmission via administration of potent and selective biarylsulfonamide AMPA potentiators LY404187 and LY451395 reverses the central effects of an acutely intoxicating dose of ethanol in the rat. Using pharmacological magnetic resonance imaging (phMRI), we observed that LY404187 attenuated ethanol-induced reductions in blood oxygenation level dependent (BOLD) in the anesthetized rat brain. A similar attenuation was apparent when measuring local cerebral glucose utilization (LCGU) via C14-2-deoxyglucose autoradiography in freely moving conscious rats. Both LY404187 and LY451395 significantly and dose-dependently reversed ethanol-induced deficits in both motor coordination and disruptions in an operant task where animals were trained to press a lever for food reward. Both prophylactic and acute intervention treatment with LY404187 reversed ethanol-induced deficits in motor coordination. Given that LY451395 and related AMPA receptor potentiators/ampakines are tolerated in both healthy volunteers and elderly patients, these data suggest that such compounds may form a potential management strategy for acute alcohol intoxication.

  18. High content screening for G protein-coupled receptors using cell-based protein translocation assays.

    PubMed

    Grånäs, Charlotta; Lundholt, Betina Kerstin; Heydorn, Arne; Linde, Viggo; Pedersen, Hans-Christian; Krog-Jensen, Christian; Rosenkilde, Mette M; Pagliaro, Len

    2005-06-01

    G protein-coupled receptors (GPCRs) have been one of the most productive classes of drug targets for several decades, and new technologies for GPCR-based discovery promise to keep this field active for years to come. While molecular screens for GPCR receptor agonist- and antagonist-based drugs will continue to be valuable discovery tools, the most exciting developments in the field involve cell-based assays for GPCR function. Some cell-based discovery strategies, such as the use of beta-arrestin as a surrogate marker for GPCR function, have already been reduced to practice, and have been used as valuable discovery tools for several years. The application of high content cell-based screening to GPCR discovery has opened up additional possibilities, such as direct tracking of GPCRs, G proteins and other signaling pathway components using intracellular translocation assays. These assays provide the capability to probe GPCR function at the cellular level with better resolution than has previously been possible, and offer practical strategies for more definitive selectivity evaluation and counter-screening in the early stages of drug discovery. The potential of cell-based translocation assays for GPCR discovery is described, and proof-of-concept data from a pilot screen with a CXCR4 assay are presented. This chemokine receptor is a highly relevant drug target which plays an important role in the pathogenesis of inflammatory disease and also has been shown to be a co-receptor for entry of HIV into cells as well as to play a role in metastasis of certain cancer cells.

  19. Metabotropic glutamate receptor 6 signaling enhances TRPM1 calcium channel function and increases melanin content in human melanocytes.

    PubMed

    Devi, Sulochana; Markandeya, Yogananda; Maddodi, Nityanand; Dhingra, Anuradha; Vardi, Noga; Balijepalli, Ravi C; Setaluri, Vijayasaradhi

    2013-05-01

    Mutations in TRPM1, a calcium channel expressed in retinal bipolar cells and epidermal melanocytes, cause complete congenital stationary night blindness with no discernible skin phenotype. In the retina, TRPM1 activity is negatively coupled to metabotropic glutamate receptor 6 (mGluR6) signaling through Gαo and TRPM1 mutations result in the loss of responsiveness of TRPM1 to mGluR6 signaling. Here, we show that human melanocytes express mGluR6, and treatment of melanocytes with L-AP4, a type III mGluR-selective agonist, enhances Ca(2+) uptake. Knockdown of TRPM1 or mGluR6 by shRNA abolished L-AP4-induced Ca(2+) influx and TRPM1 currents, showing that TRPM1 activity in melanocytes is positively coupled to mGluR6 signaling. Gαo protein is absent in melanocytes. However, forced expression of Gαo restored negative coupling of TRPM1 to mGluR6 signaling, but treatment with pertussis toxin, an inhibitor of Gi /Go proteins, did not affect basal or mGluR6-induced Ca(2+) uptake. Additionally, chronic stimulation of mGluR6 altered melanocyte morphology and increased melanin content. These data suggest differences in coupling of TRPM1 function to mGluR6 signaling explain different cellular responses to glutamate in the retina and the skin.

  20. Metabotropic glutamate receptor 6 signaling enhances TRPM1 calcium channel function and increases melanin content in human melanocytes

    PubMed Central

    Devi, Sulochana; Markandeya, Yogananda; Maddodi, Nityanand; Dhingra, Anuradha; Vardi, Noga; Balijepalli, Ravi C; Setaluri, Vijayasaradhi

    2013-01-01

    SUMMARY Mutations in TRPM1, a calcium channel expressed in retinal bipolar cells and epidermal melanocytes, cause complete congenital stationary night blindness with no discernible skin phenotype. In the retina, TRPM1 activity is negatively coupled to metabotropic glutamate receptor 6 (mGluR6) signaling through Gαo and TRPM1 mutations result in the loss of responsiveness of TRPM1 to mGluR6 signaling. Here, we show that human melanocytes express mGluR6 and treatment of melanocytes with L-AP4, a type III mGluR-selective agonist, enhances Ca2+ uptake. Knockdown of TRPM1 or mGluR6 by shRNA abolished L-AP4-induced Ca2+ influx and TRPM1 currents showing that TRPM1 activity in melanocytes is positively coupled to mGluR6 signaling. Gαo protein is absent in melanocytes. However, forced expression of Gαo restored negative coupling of TRPM1 to mGluR6 signaling, but treatment with and pertussis toxin, an inhibitor of Gi/Go proteins, did not affect basal or mGluR6-induced Ca2+ uptake. Additionally, chronic stimulation of mGluR6 altered melanocyte morphology and increased melanin content. These data suggest differences in coupling of TRPM1 function to mGluR6 signaling explain different cellular responses to glutamate in the retina and the skin. PMID:23452348

  1. ZINC-INDUCED EGF RECEPTOR SIGNALING REQUIRES SRC-MEDIATED PHOSPHORYLATION OF THE EGF RECEPTOR ON TYROSINE 845 (Y845)

    EPA Science Inventory

    ZINC-INDUCED EGF RECEPTOR SIGNALING REQUIRES Src-MEDIATED PHOSPHORYLATION OF THE EGF RECEPTOR ON TYROSINE 845 (Y845)
    Weidong Wu1, Lee M. Graves2, Gordon N. Gill3 and James M. Samet4 1Center for Environmental Medicine and Lung Biology; 2Department of Pharmacology, University o...

  2. Anxious behavior induces elevated hippocampal Cb2 receptor gene expression.

    PubMed

    Robertson, James M; Achua, Justin K; Smith, Justin P; Prince, Melissa A; Staton, Clarissa D; Ronan, Patrick J; Summers, Tangi R; Summers, Cliff H

    2017-04-07

    Anxiety is differentially expressed across a continuum of stressful/fearful intensity, influenced endocannabinoid systems and receptors. The hippocampus plays important roles in the regulation of affective behavior, emotion, and anxiety, as well as memory. Location of Cb1/Cb2 receptor action could be important in determining emotional valence, because while the dorsal hippocampus is involved in spatial memory and cognition, the ventral hippocampus has projections to the PFC, BNST, amygdala, and HPA axis, and is important for emotional responses to stress. During repeated social defeat in a Stress-Alternatives Model arena (SAM; an oval open field with escape portals only large enough for smaller mice), smaller C57BL6/N mice are subject to fear conditioning (tone=CS), and attacked by novel larger aggressive CD1 mice (US) over four daily (5min) trials. Each SAM trial presents an opportunity for escape or submission, with stable behavioral responses established by the second day of interaction. Additional groups had access to a running wheel. Social aggression plus fear conditioning stimulates enhanced Cb2 receptor gene expression in the dorsal CA1, dorsal and ventral dentate gyrus subregions in animals displaying a submissive behavioral phenotype. Escape behavior is associated with reduced Cb2 expression in the dorsal CA1 region, with freezing and escape latency correlated with mRNA levels. Escaping and submitting animals with access to running wheels had increased Cb2 mRNA in dorsal DG/CA1. These results suggest that the Cb2 receptor system is rapidly induced during anxiogenic social interactions plus fear conditioning or exercise; with responses potentially adaptive for coping mechanisms.

  3. Angiotensin (1-7) induces MAS receptor internalization.

    PubMed

    Gironacci, Mariela M; Adamo, Hugo P; Corradi, Gerardo; Santos, Robson A; Ortiz, Pablo; Carretero, Oscar A

    2011-08-01

    Angiotensin (Ang) (1-7) is the endogenous ligand for the G protein-coupled receptor Mas, a receptor associated with cardiac, renal, and cerebral protective responses. Physiological evidence suggests that Mas receptor (MasR) undergoes agonist-dependent desensitization, but the underlying molecular mechanism regulating receptor activity is unknown. We investigated the hypothesis that MasR desensitizes and internalizes on stimulation with Ang-(1-7). For this purpose, we generated a chimera between the MasR and the yellow fluorescent protein (YFP; MasR-YFP). MasR-YFP-transfected HEK 293T cells were incubated with Ang-(1-7), and the relative cellular distribution of MasR-YFP was observed by confocal microscopy. In resting cells, MasR-YFP was mostly localized to the cell membrane. Ang-(1-7) induced a redistribution of MasR-YFP to intracellular vesicles of various sizes after 5 minutes. Following the time course of [(125)I]Ang-(1-7) endocytosis, we observed that half of MasR-YFP underwent endocytosis after 10 minutes, and this was blocked by a MasR antagonist. MasR-YFP colocalized with Rab5, the early endosome antigen 1, and the adaptor protein complex 2, indicating that the R is internalized through a clathrin-mediated pathway and targeted to early endosomes after Ang-(1-7) stimulation. A fraction of MasR-YFP also colocalized with caveolin 1, suggesting that at some point MasR-YFP traverses caveolin 1-positive compartments. In conclusion, MasR undergoes endocytosis on stimulation with Ang-(1-7), and this event may explain the desensitization of MasR responsiveness. In this way, MasR activity and density may be tightly controlled by the cell.

  4. Histological grade and steroid receptor content of primary breast cancer--impact on prognosis and possible modes of action.

    PubMed Central

    Kamby, C.; Andersen, J.; Ejlertsen, B.; Birkler, N. E.; Rytter, L.; Zedeler, K.; Thorpe, S. M.; Nørgaard, T.; Rose, C.

    1988-01-01

    The clinical course of breast cancer was related to degree of anaplasia (DA) and steroid receptor (SR) content of primary tumours in 743 patients (pts) with clinical recurrence, initially enrolled in the DBCG-77 protocols. The oestrogen receptor (ER) and the progesterone receptor (PgR) content was known in 110 and 67 pts. The recurrence-free interval, survival after recurrence, and the overall survival were all prolonged in patients with well differentiated tumours or with high SR content. The tumour growth rates were estimated as clinical rates of progression (i.e., the time elapsed from a single distant metastasis until dissemination). The progression rate was prolonged in relatively well differentiated as well as in receptor rich tumours. The extent of dissemination, as indicated by the number of metastatic sites, was not associated with either DA or SR content. However, the anatomical distribution of metastases varied with both DA and SR content: signs of poor prognosis (high DA or low SR content) were associated with occurrence of visceral metastases. In contrast, SR rich tumours had a propensity for recurrence in bone. The results suggest that the impact on prognosis of the features examined here includes both variations in growth rate and metastatic pattern. PMID:3207602

  5. β-caryophyllene ameliorates cisplatin-induced nephrotoxicity in a cannabinoid 2 receptor-dependent manner

    PubMed Central

    Horváth, Béla; Mukhopadhyay, Partha; Kechrid, Malek; Patel, Vivek; Tanashian, Galin; Wink, David A.; Gertsch, Jürg; Pacher, Pál

    2012-01-01

    (E)-β-caryophyllene (BCP) is a natural sequiterpene found in many essential oils of spice (best known for contributing to the spiciness of black pepper) and food plants with recognized anti-inflammatory properties. Recently it was shown that BCP is a natural agonist of endogenous cannabinoid 2 (CB2) receptors, which are expressed in immune cells and mediate anti-inflammatory effects. In this study we aimed to test the effects of BCP in a clinically relevant murine model of nephropathy (induced by the widely used antineoplastic drug cisplatin) in which the tubular injury is largely dependent on inflammation and oxidative/nitrative stress. β-caryophyllene dose-dependently ameliorated cisplatin-induced kidney dysfunction, morphological damage, and renal inflammatory response (chemokines MCP-1 and MIP-2, cytokines TNF-α and IL-1β, adhesion molecule ICAM-1, and neutrophil and macrophage infiltration). It also markedly mitigated oxidative/nitrative stress (NOX-2, NOX-4 expression, 4-HNE and 3-NT content) and cell death. The protective effects of BCP against biochemical and histological markers of nephropathy were absent in CB2 knockout mice. Thus, BCP may be an excellent therapeutic agent to prevent cisplatin-induced nephrotoxicity through a CB2 receptor dependent pathway. Given the excellent safety profile of BCP in humans it has tremendous therapeutic potential in multitude of diseases associated with inflammation and oxidative stress. PMID:22326488

  6. β-Caryophyllene ameliorates cisplatin-induced nephrotoxicity in a cannabinoid 2 receptor-dependent manner.

    PubMed

    Horváth, Béla; Mukhopadhyay, Partha; Kechrid, Malek; Patel, Vivek; Tanchian, Galin; Wink, David A; Gertsch, Jürg; Pacher, Pál

    2012-04-15

    (E)-β-caryophyllene (BCP) is a natural sesquiterpene found in many essential oils of spice (best known for contributing to the spiciness of black pepper) and food plants with recognized anti-inflammatory properties. Recently it was shown that BCP is a natural agonist of endogenous cannabinoid 2 (CB(2)) receptors, which are expressed in immune cells and mediate anti-inflammatory effects. In this study we aimed to test the effects of BCP in a clinically relevant murine model of nephropathy (induced by the widely used antineoplastic drug cisplatin) in which the tubular injury is largely dependent on inflammation and oxidative/nitrative stress. β-caryophyllene dose-dependently ameliorated cisplatin-induced kidney dysfunction, morphological damage, and renal inflammatory response (chemokines MCP-1 and MIP-2, cytokines TNF-α and IL-1β, adhesion molecule ICAM-1, and neutrophil and macrophage infiltration). It also markedly mitigated oxidative/nitrative stress (NOX-2 and NOX-4 expression, 4-HNE and 3-NT content) and cell death. The protective effects of BCP against biochemical and histological markers of nephropathy were absent in CB(2) knockout mice. Thus, BCP may be an excellent therapeutic agent to prevent cisplatin-induced nephrotoxicity through a CB(2) receptor-dependent pathway. Given the excellent safety profile of BCP in humans it has tremendous therapeutic potential in a multitude of diseases associated with inflammation and oxidative stress.

  7. Common molecular mechanisms in field- and agrin-induced acetylcholine receptor clustering.

    PubMed

    Sabrina, F; Stollberg, J

    1997-04-01

    1. The aggregation of acetylcholine receptors at the developing neuromuscular junction is critical to the development and function of this synapse. In vitro studies have shown that receptor aggregation can be induced by the finding of agrin to the muscle cell surface and by the electric field-induced concentration of a (nonreceptor) molecule at the cathodal cell pole. 2. We report here on the interaction between agrin binding and electric fields with respect to the distribution of receptors and agrin binding sites. 3. (a) Pretreatment of cells with agrin completely blocks the development of field-induced receptor clusters. (b) Field-induced aggregation of receptors precedes the field-induced aggregation of agrin binding sites by approximately 30 min. (c) Electric fields prevent agrin-induced receptor clustering despite the presence of agrin binding sites and freely diffusing receptors. 4. These results indicate that another membrane component-but not the agrin binding site and not the receptor-is required for agrin-induced receptor clustering. They also suggest that electric fields and agrin cause receptor clustering via common molecular mechanisms.

  8. P2X7 Receptor Modulates Inflammatory and Functional Pulmonary Changes Induced by Silica

    PubMed Central

    Santana, Patrícia T.; Vieira, Flávia S.; da Graça, Carolyne Lalucha A. L.; Marques-da-Silva, Camila; Machado, Mariana N.; Caruso-Neves, Celso; Zin, Walter A.; Borojevic, Radovan; Coutinho-Silva, Robson

    2014-01-01

    Silicosis is an occupational lung disease, characterized by irreversible and progressive fibrosis. Silica exposure leads to intense lung inflammation, reactive oxygen production, and extracellular ATP (eATP) release by macrophages. The P2X7 purinergic receptor is thought to be an important immunomodulator that responds to eATP in sites of inflammation and tissue damage. The present study investigates the role of P2X7 receptor in a murine model of silicosis. To that end wild-type (C57BL/6) and P2X7 receptor knockout mice received intratracheal injection of saline or silica particles. After 14 days, changes in lung mechanics were determined by the end-inflation occlusion method. Bronchoalveolar lavage and flow cytometry analyzes were performed. Lungs were harvested for histological and immunochemistry analysis of fibers content, inflammatory infiltration, apoptosis, as well as cytokine and oxidative stress expression. Silica particle effects on lung alveolar macrophages and fibroblasts were also evaluated in cell line cultures. Phagocytosis assay was performed in peritoneal macrophages. Silica exposure increased lung mechanical parameters in wild-type but not in P2X7 knockout mice. Inflammatory cell infiltration and collagen deposition in lung parenchyma, apoptosis, TGF-β and NF-κB activation, as well as nitric oxide, reactive oxygen species (ROS) and IL-1β secretion were higher in wild-type than knockout silica-exposed mice. In vitro studies suggested that P2X7 receptor participates in silica particle phagocytosis, IL-1β secretion, as well as reactive oxygen species and nitric oxide production. In conclusion, our data showed a significant role for P2X7 receptor in silica-induced lung changes, modulating lung inflammatory, fibrotic, and functional changes. PMID:25310682

  9. Sulforaphane-induced apoptosis involves the type 1 IP3 receptor

    PubMed Central

    Hudecova, Sona; Markova, Jana; Simko, Veronika; Csaderova, Lucia; Stracina, Tibor; Sirova, Marta; Fojtu, Michaela; Svastova, Eliska; Gronesova, Paulina; Pastorek, Michal; Novakova, Marie; Cholujova, Dana; Kopacek, Juraj; Pastorekova, Silvia; Sedlak, Jan; Krizanova, Olga

    2016-01-01

    In this study we show that anti-tumor effect of sulforaphane (SFN) is partially realized through the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). This effect was verified in vitro on three different stable cell lines and also in vivo on the model of nude mice with developed tumors. Early response (6 hours) of A2780 ovarian carcinoma cells to SFN treatment involves generation of mitochondrial ROS and increased transcription of NRF2 and its downstream regulated genes including heme oxygenase 1, NAD(P)H:quinine oxidoreductase 1, and KLF9. Prolonged SFN treatment (24 hours) upregulated expression of NRF2 and IP3R1. SFN induces a time-dependent phosphorylation wave of HSP27. Use of IP3R inhibitor Xestospongin C (Xest) attenuates both SFN-induced apoptosis and the level of NRF2 protein expression. In addition, Xest partially attenuates anti-tumor effect of SFN in vivo. SFN-induced apoptosis is completely inhibited by silencing of IP3R1 gene but only partially blocked by silencing of NRF2; silencing of IP3R2 and IP3R3 had no effect on these cells. Xest inhibitor does not significantly modify SFN-induced increase in the rapid activity of ARE and AP1 responsive elements. We found that Xest effectively reverses the SFN-dependent increase of nuclear content and decrease of reticular calcium content. In addition, immunofluorescent staining with IP3R1 antibody revealed that SFN treatment induces translocation of IP3R1 to the nucleus. Our results clearly show that IP3R1 is involved in SFN-induced apoptosis through the depletion of reticular calcium and modulation of transcription factors through nuclear calcium up-regulation. PMID:27528021

  10. 5-HT2A receptor activation is necessary for CO2-induced arousal

    PubMed Central

    Smith, Haleigh R.; MacAskill, Amanda; Richerson, George B.

    2015-01-01

    Hypercapnia-induced arousal from sleep is an important protective mechanism pertinent to a number of diseases. Most notably among these are the sudden infant death syndrome, obstructive sleep apnea and sudden unexpected death in epilepsy. Serotonin (5-HT) plays a significant role in hypercapnia-induced arousal. The mechanism of 5-HT's role in this protective response is unknown. Here we sought to identify the specific 5-HT receptor subtype(s) involved in this response. Wild-type mice were pretreated with antagonists against 5-HT receptor subtypes, as well as antagonists against adrenergic, cholinergic, histaminergic, dopaminergic, and orexinergic receptors before challenge with inspired CO2 or hypoxia. Antagonists of 5-HT2A receptors dose-dependently blocked CO2-induced arousal. The 5-HT2C receptor antagonist, RS-102221, and the 5-HT1A receptor agonist, 8-OH-DPAT, attenuated but did not completely block CO2-induced arousal. Blockade of non-5-HT receptors did not affect CO2-induced arousal. None of these drugs had any effect on hypoxia-induced arousal. 5-HT2 receptor agonists were given to mice in which 5-HT neurons had been genetically eliminated during embryonic life (Lmx1bf/f/p) and which are known to lack CO2-induced arousal. Application of agonists to 5-HT2A, but not 5-HT2C, receptors, dose-dependently restored CO2-induced arousal in these mice. These data identify the 5-HT2A receptor as an important mediator of CO2-induced arousal and suggest that, while 5-HT neurons can be independently activated to drive CO2-induced arousal, in the absence of 5-HT neurons and endogenous 5-HT, 5-HT receptor activation can act in a permissive fashion to facilitate CO2-induced arousal via another as yet unidentified chemosensor system. PMID:25925320

  11. Binding of amyloid beta peptide to beta2 adrenergic receptor induces PKA-dependent AMPA receptor hyperactivity.

    PubMed

    Wang, Dayong; Govindaiah, G; Liu, Ruijie; De Arcangelis, Vania; Cox, Charles L; Xiang, Yang K

    2010-09-01

    Progressive decrease in neuronal function is an established feature of Alzheimer's disease (AD). Previous studies have shown that amyloid beta (Abeta) peptide induces acute increase in spontaneous synaptic activity accompanied by neurotoxicity, and Abeta induces excitotoxic neuronal death by increasing calcium influx mediated by hyperactive alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors. An in vivo study has revealed subpopulations of hyperactive neurons near Abeta plaques in mutant amyloid precursor protein (APP)-transgenic animal model of Alzheimer's disease (AD) that can be normalized by an AMPA receptor antagonist. In the present study, we aim to determine whether soluble Abeta acutely induces hyperactivity of AMPA receptors by a mechanism involving beta(2) adrenergic receptor (beta(2)AR). We found that the soluble Abeta binds to beta(2)AR, and the extracellular N terminus of beta(2)AR is critical for the binding. The binding is required to induce G-protein/cAMP/protein kinase A (PKA) signaling, which controls PKA-dependent phosphorylation of GluR1 and beta(2)AR, and AMPA receptor-mediated excitatory postsynaptic currents (EPSCs). beta(2)AR and GluR1 also form a complex comprising postsynaptic density protein 95 (PSD95), PKA and its anchor AKAP150, and protein phosphotase 2A (PP2A). Both the third intracellular (i3) loop and C terminus of beta(2)AR are required for the beta(2)AR/AMPA receptor complex. Abeta acutely induces PKA phosphorylation of GluR1 in the complex without affecting the association between two receptors. The present study reveals that non-neurotransmitter Abeta has a binding capacity to beta(2)AR and induces PKA-dependent hyperactivity in AMPA receptors.

  12. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces death receptor 5 networks that are highly organized.

    PubMed

    Valley, Christopher C; Lewis, Andrew K; Mudaliar, Deepti J; Perlmutter, Jason D; Braun, Anthony R; Karim, Christine B; Thomas, David D; Brody, Jonathan R; Sachs, Jonathan N

    2012-06-15

    Recent evidence suggests that TNF-related apoptosis-inducing ligand (TRAIL), a death-inducing cytokine with anti-tumor potential, initiates apoptosis by re-organizing TRAIL receptors into large clusters, although the structure of these clusters and the mechanism by which they assemble are unknown. Here, we demonstrate that TRAIL receptor 2 (DR5) forms receptor dimers in a ligand-dependent manner at endogenous receptor levels, and these receptor dimers exist within high molecular weight networks. Using mutational analysis, FRET, fluorescence microscopy, synthetic biochemistry, and molecular modeling, we find that receptor dimerization relies upon covalent and noncovalent interactions between membrane-proximal residues. Additionally, by using FRET, we show that the oligomeric structure of two functional isoforms of DR5 is indistinguishable. The resulting model of DR5 activation should revise the accepted architecture of the functioning units of DR5 and the structurally homologous TNF receptor superfamily members.

  13. Ethanol inhibits neuritogenesis induced by astrocyte muscarinic receptors.

    PubMed

    Guizzetti, Marina; Moore, Nadia H; Giordano, Gennaro; VanDeMark, Kathryn L; Costa, Lucio G

    2010-09-01

    In utero alcohol exposure can lead to fetal alcohol spectrum disorders, characterized by cognitive and behavioral deficits. In vivo and in vitro studies have shown that ethanol alters neuronal development. We have recently shown that stimulation of M(3) muscarinic receptors in astrocytes increases the synthesis and release of fibronectin, laminin, and plasminogen activator inhibitor-1, causing neurite outgrowth in hippocampal neurons. As M(3) muscarinic receptor signaling in astroglial cells is strongly inhibited by ethanol, we hypothesized that ethanol may also inhibit neuritogenesis in hippocampal neurons induced by carbachol-stimulated astrocytes. In the present study, we report that the effect of carbachol-stimulated astrocytes on hippocampal neuron neurite outgrowth was inhibited in a concentration-dependent manner (25-100 mM) by ethanol. This effect was because of the inhibition of the release of fibronectin, laminin, and plasminogen activator inhibitor-1. Similar effects on neuritogenesis and on the release of astrocyte extracellular proteins were observed after the incubation of astrocytes with carbachol in the presence of 1-butanol, another short-chain alcohol, which like ethanol is a competitive substrate for phospholipase D, but not by tert-butanol, its analog that is not a substrate for this enzyme. This study identifies a potential novel mechanism involved in the developmental effects of ethanol mediated by the interaction of ethanol with cell signaling in astrocytes, leading to an impairment in neuron-astrocyte communication.

  14. Chemotherapy-induced antitumor immunity requires formyl peptide receptor 1.

    PubMed

    Vacchelli, Erika; Ma, Yuting; Baracco, Elisa E; Sistigu, Antonella; Enot, David P; Pietrocola, Federico; Yang, Heng; Adjemian, Sandy; Chaba, Kariman; Semeraro, Michaela; Signore, Michele; De Ninno, Adele; Lucarini, Valeria; Peschiaroli, Francesca; Businaro, Luca; Gerardino, Annamaria; Manic, Gwenola; Ulas, Thomas; Günther, Patrick; Schultze, Joachim L; Kepp, Oliver; Stoll, Gautier; Lefebvre, Céline; Mulot, Claire; Castoldi, Francesca; Rusakiewicz, Sylvie; Ladoire, Sylvain; Apetoh, Lionel; Bravo-San Pedro, José Manuel; Lucattelli, Monica; Delarasse, Cécile; Boige, Valérie; Ducreux, Michel; Delaloge, Suzette; Borg, Christophe; André, Fabrice; Schiavoni, Giovanna; Vitale, Ilio; Laurent-Puig, Pierre; Mattei, Fabrizio; Zitvogel, Laurence; Kroemer, Guido

    2015-11-20

    Antitumor immunity driven by intratumoral dendritic cells contributes to the efficacy of anthracycline-based chemotherapy in cancer. We identified a loss-of-function allele of the gene coding for formyl peptide receptor 1 (FPR1) that was associated with poor metastasis-free and overall survival in breast and colorectal cancer patients receiving adjuvant chemotherapy. The therapeutic effects of anthracyclines were abrogated in tumor-bearing Fpr1(-/-) mice due to impaired antitumor immunity. Fpr1-deficient dendritic cells failed to approach dying cancer cells and, as a result, could not elicit antitumor T cell immunity. Experiments performed in a microfluidic device confirmed that FPR1 and its ligand, annexin-1, promoted stable interactions between dying cancer cells and human or murine leukocytes. Altogether, these results highlight the importance of FPR1 in chemotherapy-induced anticancer immune responses.

  15. Ligand-induced IFN gamma receptor tyrosine phosphorylation couples the receptor to its signal transduction system (p91).

    PubMed Central

    Greenlund, A C; Farrar, M A; Viviano, B L; Schreiber, R D

    1994-01-01

    Herein we report that interferon-gamma (IFN gamma) induces the rapid and reversible tyrosine phosphorylation of the IFN gamma receptor. Using a panel of receptor intracellular domain mutants, we show that a membrane-proximal LPKS sequence (residues 266-269) is required for ligand-induced tyrosine kinase activation and/or kinase-receptor association and biological responsiveness, and a functionally critical membrane-distal tyrosine residue (Y440) is a target of the activated enzyme. The biological significance of Y440 phosphorylation was demonstrated by showing that a receptor-derived nonapeptide corresponding to receptor residues 436-444 and containing phosphorylated Y440 bound specifically to p91, blocked p91 phosphorylation and inhibited the generation of an active p91-containing transcription factor complex. In contrast, nonphosphorylated wild-type, phosphorylated mutant, or phosphorylated irrelevant peptides did not. Moreover, the phosphorylated Y440-containing peptide did not interact with a related but distinct latent transcription factor (p113) which is activatible by IFN alpha but not IFN gamma. These results thus document the specific and inducible association of p91 with the phosphorylated IFN gamma receptor and thereby elucidate the mechanism by which ligand couples the IFN gamma receptor to its signal transduction system. Images PMID:8156998

  16. GABAB receptor agonist baclofen improves methamphetamine-induced cognitive deficit in mice.

    PubMed

    Arai, Sawako; Takuma, Kazuhiro; Mizoguchi, Hiroyuki; Ibi, Daisuke; Nagai, Taku; Kamei, Hiroyuki; Kim, Hyoung-Chun; Yamada, Kiyofumi

    2009-01-05

    In this study, we investigated the effects of GABA(A) and GABA(B) receptor agonists on the methamphetamine-induced impairment of recognition memory in mice. Repeated treatment with methamphetamine at a dose of 1 mg/kg for 7 days induced an impairment of recognition memory. Baclofen, a GABA(B) receptor agonist, ameliorated the repeated methamphetamine-induced cognitive impairment, although gaboxadol, a GABA(A) receptor agonist, had no significant effect. GABA(B) receptors may constitute a putative new target in treating cognitive deficits in patients suffering from schizophrenia, as well as methamphetamine psychosis.

  17. Nicotine induces fibrogenic changes in human liver via nicotinic acetylcholine receptors expressed on hepatic stellate cells

    SciTech Connect

    Soeda, Junpei; Morgan, Maelle; McKee, Chad; Mouralidarane, Angelina; Lin, ChingI; Roskams, Tania; Oben, Jude A.

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Cigarette smoke may induce liver fibrosis via nicotine receptors. Black-Right-Pointing-Pointer Nicotine induces proliferation of hepatic stellate cells (HSCs). Black-Right-Pointing-Pointer Nicotine activates hepatic fibrogenic pathways. Black-Right-Pointing-Pointer Nicotine receptor antagonists attenuate HSC proliferation. Black-Right-Pointing-Pointer Nicotinic receptor antagonists may have utility as novel anti-fibrotic agents. -- Abstract: Background and aims: Cigarette smoke (CS) may cause liver fibrosis but possible involved mechanisms are unclear. Among the many chemicals in CS is nicotine - which affects cells through nicotinic acetylcholine receptors (nAChR). We studied the effects of nicotine, and involved pathways, on human primary hepatic stellate cells (hHSCs), the principal fibrogenic cells in the liver. We then determined possible disease relevance by assaying nAChR in liver samples from human non-alcoholic steatohepatitis (NASH). Methods: hHSC were isolated from healthy human livers and nAChR expression analyzed - RT-PCR and Western blotting. Nicotine induction of hHSC proliferation, upregulation of collagen1-{alpha}2 and the pro-fibrogenic cytokine transforming growth factor beta 1 (TGF-{beta}1) was determined along with involved intracellular signaling pathways. nAChR mRNA expression was finally analyzed in whole liver biopsies obtained from patients diagnosed with non-alcoholic steatohepatitis (NASH). Results: hHSCs express muscle type ({alpha}1, {beta}1, delta and epsilon) and neuronal type ({alpha}3, {alpha}6, {alpha}7, {beta}2 and {beta}4) nAChR subunits at the mRNA level. Among these subunits, {alpha}3, {alpha}7, {beta}1 and {epsilon} were predominantly expressed as confirmed by Western blotting. Nicotine induced hHSC proliferation was attenuated by mecamylamine (p < 0.05). Additionally, collagen1-{alpha}2 and TGF-{beta}1 mRNA expression were significantly upregulated by nicotine and inhibited by

  18. Kainate receptor activation induces glycine receptor endocytosis through PKC deSUMOylation

    PubMed Central

    Sun, Hao; Lu, Li; Zuo, Yong; Wang, Yan; Jiao, Yingfu; Zeng, Wei-Zheng; Huang, Chao; Zhu, Michael X.; Zamponi, Gerald W.; Zhou, Tong; Xu, Tian-Le; Cheng, Jinke; Li, Yong

    2014-01-01

    Surface expression and regulated endocytosis of glycine receptors (GlyRs) play a critical function in balancing neuronal excitability. SUMOylation (SUMO modification) is of critical importance for maintaining neuronal function in the central nervous system. Here we show that activation of kainate receptors (KARs) causes GlyR endocytosis in a calcium- and protein kinase C (PKC)-dependent manner, leading to reduced GlyR-mediated synaptic activity in cultured spinal cord neurons and the superficial dorsal horn of rat spinal cord slices. This effect requires SUMO1/sentrin-specific peptidase 1 (SENP1)-mediated deSUMOylation of PKC, indicating that the crosstalk between KARs and GlyRs relies on the SUMOylation status of PKC. SENP1-mediated deSUMOylation of PKC is involved in the kainate-induced GlyR endocytosis and thus plays an important role in the anti-homeostatic regulation between excitatory and inhibitory ligand-gated ion channels. Altogether, we have identified a SUMOylation-dependent regulatory pathway for GlyR endocytosis, which may have important physiological implications for proper neuronal excitability. PMID:25236484

  19. Identification of Human-Induced Changes in Atmospheric Moisture Content

    NASA Technical Reports Server (NTRS)

    Santer, B.D.; Mears, C.; Wentz, F.J.; Taylor, K.E.; Gleckler, P.J.; Wigley, T.M.; Barnett, T.P.; Boyle, J.S.; Bruggemann, W.; Gillett, N.P.; Klein, S.A.; Meehl, G.A.; Nozawa, T.; Pierce, D.W.; Scott, P.A.; Washington, W.M.; Wehner, M.F.

    2007-01-01

    Data from the satellite-based Special Sensor Microwave Imager (SSM/I) show that the total atmospheric moisture content over oceans has increased by 0.41 kg/sq m per decade since 1988. Results from current climate models indicate that water vapor increases of this magnitude cannot be explained by climate noise alone. In a formal detection and attribution analysis using the pooled results from 22 different climate models, the simulated "fingerprint" pattern of anthropogenically caused changes in water vapor is identifiable with high statistical confidence in the SSM/I data. Experiments in which forcing factors are varied individually suggest that this fingerprint "match" is primarily due to human-caused increases in greenhouse gases and not to solar forcing or recovery from the eruption of Mount Pinatubo. Our findings provide preliminary evidence of an emerging anthropogenic signal in the moisture content of earth's atmosphere.

  20. Identification of human-induced changes in atmospheric moisture content

    PubMed Central

    Santer, B. D.; Mears, C.; Wentz, F. J.; Taylor, K. E.; Gleckler, P. J.; Wigley, T. M. L.; Barnett, T. P.; Boyle, J. S.; Brüggemann, W.; Gillett, N. P.; Klein, S. A.; Meehl, G. A.; Nozawa, T.; Pierce, D. W.; Stott, P. A.; Washington, W. M.; Wehner, M. F.

    2007-01-01

    Data from the satellite-based Special Sensor Microwave Imager (SSM/I) show that the total atmospheric moisture content over oceans has increased by 0.41 kg/m2 per decade since 1988. Results from current climate models indicate that water vapor increases of this magnitude cannot be explained by climate noise alone. In a formal detection and attribution analysis using the pooled results from 22 different climate models, the simulated “fingerprint” pattern of anthropogenically caused changes in water vapor is identifiable with high statistical confidence in the SSM/I data. Experiments in which forcing factors are varied individually suggest that this fingerprint “match” is primarily due to human-caused increases in greenhouse gases and not to solar forcing or recovery from the eruption of Mount Pinatubo. Our findings provide preliminary evidence of an emerging anthropogenic signal in the moisture content of earth's atmosphere. PMID:17881573

  1. NMDA Receptor Antagonist Attenuates Bleomycin-Induced Acute Lung Injury

    PubMed Central

    Li, Yang; Liu, Yong; Peng, XiangPing; Liu, Wei; Zhao, FeiYan; Feng, DanDan; Han, JianZhong; Huang, YanHong; Luo, SiWei; Li, Lian; Yue, Shao Jie; Cheng, QingMei; Huang, XiaoTing; Luo, ZiQiang

    2015-01-01

    Background Glutamate is a major neurotransmitter in the central nervous system (CNS). Large amount of glutamate can overstimulate N-methyl-D-aspartate receptor (NMDAR), causing neuronal injury and death. Recently, NMDAR has been reported to be found in the lungs. The aim of this study is to examine the effects of memantine, a NMDAR channel blocker, on bleomycin-induced lung injury mice. Methods C57BL/6 mice were intratracheally injected with bleomycin (BLM) to induce lung injury. Mice were randomized to receive saline, memantine (Me), BLM, BLM plus Me. Lungs and BALF were harvested on day 3 or 7 for further evaluation. Results BLM caused leukocyte infiltration, pulmonary edema and increase in cytokines, and imposed significant oxidative stress (MDA as a marker) in lungs. Memantine significantly mitigated the oxidative stress, lung inflammatory response and acute lung injury caused by BLM. Moreover, activation of NMDAR enhances CD11b expression on neutrophils. Conclusions Memantine mitigates oxidative stress, lung inflammatory response and acute lung injury in BLM challenged mice. PMID:25942563

  2. Recombinant interleukin-1 receptor antagonist attenuates the severity of chronic pancreatitis induced by TNBS in rats.

    PubMed

    Xu, Chunfang; Shen, Jiaqing; Zhang, Jing; Jia, Zhenyu; He, Zhilong; Zhuang, Xiaohui; Xu, Ting; Shi, Yuqi; Zhu, Shunying; Wu, Mingyuan; Han, Wei

    2015-02-15

    Chronic pancreatitis (CP) is a common disease in the department of gastroenterology, with the main symptoms of exocrine and/or endocrine insufficiency and abdominal pain. The pathogenic mechanism of CP is still not fully clarified and the aims of treatment now are to relieve symptoms. In this study, we attempted to find a connection between interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1Ra) in trinitrobenzene sulfonic acid (TNBS)-induced chronic pancreatitis, and then the therapeutic effect of recombinant IL-1Ra was also detected in the CP model. Chronic pancreatitis was induced by intraductal infusion of TNBS in SD rats followed by a consecutive administration of rIL-1Ra, and the histological changes and collagen content in the pancreas were measured, as well as the abdominal hypersensitivity. We found that rhIL-1Ra could attenuate the severity of chronic pancreatic injury, modulate the extracellular matrix secretion, focal proliferation and apoptosis, and cellular immunity in TNBS-induced CP. Interestingly, rIL-1Ra could also block the pancreatitis-induced referred abdominal hypersensitivity. In conclusion, IL-1Ra may play a protective role in CP and rIL-1Ra would be a potential therapeutic target for the treatment of CP, while its possible mechanisms and clinical usage still need further investigation.

  3. Agarwood induced laxative effects via acetylcholine receptors on loperamide-induced constipation in mice.

    PubMed

    Kakino, Mamoru; Izuta, Hiroshi; Ito, Tetsuro; Tsuruma, Kazuhiro; Araki, Yoko; Shimazawa, Masamitsu; Oyama, Masayoshi; Iinuma, Munekazu; Hara, Hideaki

    2010-01-01

    Agarwood (Aquilaria sinensis, Aquilaria crasna) is well known as an incense in the oriental region such as Thailand, Taiwan, and Cambodia, and is used as a digestive in traditional medicine. We investigated the laxative effects and mechanism of agarwood leaves extracted with ethanol (EEA-1, Aquilaria sinensis; EEA-2, Aquilaria crasna). EEA-1, EEA-2, the main constituents of EEAs (mangiferin, and genkwanin-5-O-primeveroside), and senna increased the frequency and weight of stools in loperamide-induced constipation model mice. EEA-1 and EEA-2 did not induce diarrhea as a side effect, but senna induced severe diarrhea. EEA-1 and senna increased gastro-intestinal (GI) transit in the model mice. EEA-1, but not senna, also increased the intestinal tension of isolated jejunum and ileum in guinea pigs, and the tension increase was blocked by atropine, a muscarinic receptor antagonist, but not by other inhibitors (granicetron, pyrilamine, or bradykinin-antagonist peptide). Furthermore, the increase in frequency and weight of stools induced by EEA-1 were blocked by pre-administration of atropine in the model mice. These findings indicate that EEAs exerted a laxative effect via acetylcholine receptors in the mouse constipation model.

  4. A Killer Immunoglobulin - Like Receptor Gene - Content Haplotype and A Cognate Human Leukocyte Antigen Ligand are Associated with Autism

    PubMed Central

    Torres, Anthony; Westover, Jonna; Benson, Michael; Johnson, Randall; Dykes, Annelise

    2016-01-01

    The killing activity of natural killer cells is largely regulated by the binding of class I human leukocyte antigen cognate ligands to killer cell immunoglobulin - like receptor proteins. The killer cell immunoglobulin - like receptor gene - complex contains genes that activate and others that inhibit the killing state of natural killer cells depending on the binding of specific human leukocyte antigen cognate ligands. It has been suggested in previous publications that activating human leukocyte antigen/killer - cell immunoglobulin - like receptor complexes are increased in people with autism. We present data, which suggests that an activating cB01/tA01 killer cell immunoglobulin - like receptor gene - content haplotype and the cognate ligand human leukocyte antigen - C1k that activates this haplotype is significantly increased in autism. This is an important observation suggesting that the interaction between two proteins encoded on different chromosomes increases natural killer cell killing in autism. PMID:27853655

  5. A Killer Immunoglobulin - Like Receptor Gene - Content Haplotype and A Cognate Human Leukocyte Antigen Ligand are Associated with Autism.

    PubMed

    Torres, Anthony; Westover, Jonna; Benson, Michael; Johnson, Randall; Dykes, Annelise

    2016-04-01

    The killing activity of natural killer cells is largely regulated by the binding of class I human leukocyte antigen cognate ligands to killer cell immunoglobulin - like receptor proteins. The killer cell immunoglobulin - like receptor gene - complex contains genes that activate and others that inhibit the killing state of natural killer cells depending on the binding of specific human leukocyte antigen cognate ligands. It has been suggested in previous publications that activating human leukocyte antigen/killer - cell immunoglobulin - like receptor complexes are increased in people with autism. We present data, which suggests that an activating cB01/tA01 killer cell immunoglobulin - like receptor gene - content haplotype and the cognate ligand human leukocyte antigen - C1k that activates this haplotype is significantly increased in autism. This is an important observation suggesting that the interaction between two proteins encoded on different chromosomes increases natural killer cell killing in autism.

  6. BURN-INDUCED ACUTE LUNG INJURY REQUIRES A FUNCTIONAL TOLL-LIKE RECEPTOR 4

    PubMed Central

    Krzyzaniak, Michael; Cheadle, Gerald; Peterson, Carrie; Loomis, William; Putnam, James; Wolf, Paul; Baird, Andrew; Eliceiri, Brian; Bansal, Vishal; Coimbra, Raul

    2014-01-01

    The role of the Toll-like receptor 4 (TLR4), a component of the innate immune system, in the development of burn-induced acute lung injury (ALI) has not been completely defined. Recent data suggested that an intact TLR4 plays a major role in the development of organ injury in sterile inflammation. We hypothesized that burn-induced ALI is a TLR4-dependent process. Male C57BL/6J (TLR4 wild-type [WT]) and C57BL/10ScN (TLR4 knockout [KO]) mice were subjected to a 30% total body surface area steam burn. Animals were killed at 6 and 24 h after the insult. Lung specimens were harvested for histological examination after hematoxylin-eosin staining. In addition, lung myeloperoxidase (MPO) and intercellular adhesion molecule 1 immunostaining was performed. Lung MPO was measured by an enzymatic assay. Total lung keratinocyte-derived chemoattractant (IL-8) content was measured by enzyme-linked immunosorbent assay. Western blot was performed to quantify phosphorylated IκBα, phosphorylated nuclear factor κB p65 (NF-κBp65), and high mobility group box 1 expression. Acute lung injury, characterized by thickening of the alveolar-capillary membrane, hyaline membrane formation, intraalveolar hemorrhage, and neutrophil infiltration, was seen in WT but not KO animals at 24 h. Myeloperoxidase and intercellular adhesion molecule 1 immunostaining of KO animals was also similar to sham but elevated in WT animals. In addition, a reduction in MPO enzymatic activity was observed in KO mice as well as a reduction in IL-8 levels compared with their WT counterparts. Burn-induced ALI develops within 24 h after the initial thermal insult in our model. Toll-like receptor 4 KO animals were clearly protected and had a much less severe lung injury. Our data suggest that burn-induced ALI is a TLR4-dependent process. PMID:21330948

  7. 5-HT2 receptors modulate the expression of antipsychotic-induced dopamine supersensitivity.

    PubMed

    Charron, Alexandra; Hage, Cynthia El; Servonnet, Alice; Samaha, Anne-Noël

    2015-12-01

    Antipsychotic treatment can produce supersensitivity to dopamine receptor stimulation. This compromises the efficacy of ongoing treatment and increases the risk of relapse to psychosis upon treatment cessation. Serotonin 5-HT2 receptors modulate dopamine function and thereby influence dopamine-dependent responses. Here we evaluated the hypothesis that 5-HT2 receptors modulate the behavioural expression of antipsychotic-induced dopamine supersensitivity. To this end, we first treated rats with the antipsychotic haloperidol using a clinically relevant treatment regimen. We then assessed the effects of a 5-HT2 receptor antagonist (ritanserin; 0.01 and 0.1mg/kg) and of a 5-HT2A receptor antagonist (MDL100,907; 0.025-0.1mg/kg) on amphetamine-induced psychomotor activity. Antipsychotic-treated rats showed increased amphetamine-induced locomotion relative to antipsychotic-naïve rats, indicating a dopamine supersensitive state. At the highest dose tested (0.1mg/kg for both antagonists), both ritanserin and MDL100,907 suppressed amphetamine-induced locomotion in antipsychotic-treated rats, while having no effect on this behaviour in control rats. In parallel, antipsychotic treatment decreased 5-HT2A receptor density in the prelimbic cortex and nucleus accumbens core and increased 5-HT2A receptor density in the caudate-putamen. Thus, activation of either 5-HT2 receptors or of 5-HT2A receptors selectively is required for the full expression of antipsychotic-induced dopamine supersensitivity. In addition, antipsychotic-induced dopamine supersensitivity enhances the ability of 5-HT2/5-HT2A receptors to modulate dopamine-dependent behaviours. These effects are potentially linked to changes in 5-HT2A receptor density in the prefrontal cortex and the striatum. These observations raise the possibility that blockade of 5-HT2A receptors might overcome some of the behavioural manifestations of antipsychotic-induced dopamine supersensitivity.

  8. Relationship of age and menopausal status to estrogen receptor content in primary carcinoma of the breast.

    PubMed Central

    McCarty, K S; Silva, J S; Cox, E B; Leight, G S; Wells, S A; McCarty, K S

    1983-01-01

    The cytosolic estrogen receptor (CER) content of 1037 primary breast carcinomas was evaluated by sucrose density gradient analysis. Tumor specimens from premenopausal patients had significantly lower levels of CER (14.6 +/- 1.5 (mean +/- SEM) 8S binding fmole/mg protein) compared with carcinomas from postmenopausal patients (57.5 +/- 3.9 fmole/mg protein; p less than 0.001). The proportion of specimens with CER levels above threshold values of 3, 7, or 10 fmoles/mg protein were significantly higher for postmenopausal patients (72%, 63%, 59%, respectively) than for premenopausal patients (56%, 42%, 36%, p less than 0.001). When compared within half-decades, no statistically significant differences between premenopausal and postmenopausal patients were observed for mean, median, or rank sums of CER levels (p greater than 0.3). When patients were compared by half-decades, both mean and ranked sums of CER levels were significantly different (p less than 0.001). The proportion of specimens that demonstrated CER levels above a threshold value of 10 fmole/mg protein increased sequentially from a low of 13/51 (26%) for patients less than 35 years to a high of 60/81 (74%) for patients greater than 75 years. PMID:6824366

  9. The estrogen receptor alpha nuclear localization sequence is critical for fulvestrant-induced degradation of the receptor.

    PubMed

    Casa, Angelo J; Hochbaum, Daniel; Sreekumar, Sreeja; Oesterreich, Steffi; Lee, Adrian V

    2015-11-05

    Fulvestrant, a selective estrogen receptor down-regulator (SERD) is a pure competitive antagonist of estrogen receptor alpha (ERα). Fulvestrant binds ERα and reduces the receptor's half-life by increasing protein turnover, however, its mechanism of action is not fully understood. In this study, we show that removal of the ERα nuclear localization sequence (ERΔNLS) resulted in a predominantly cytoplasmic ERα that was degraded in response to 17-β-estradiol (E2) but was resistant to degradation by fulvestrant. ERΔNLS bound the ligands and exhibited receptor interaction similar to ERα, indicating that the lack of degradation was not due to disruption of these processes. Forcing ERΔNLS into the nucleus with a heterologous SV40-NLS did not restore degradation, suggesting that the NLS domain itself, and not merely receptor localization, is critical for fulvestrant-induced ERα degradation. Indeed, cloning of the endogenous ERα NLS onto the N-terminus of ERΔNLS significantly restored both its nuclear localization and turnover in response to fulvestrant. Moreover, mutation of the sumoylation targets K266 and K268 within the NLS impaired fulvestrant-induced ERα degradation. In conclusion, our study provides evidence for the unique role of the ERα NLS in fulvestrant-induced degradation of the receptor.

  10. Antiangiogenic effect of angiotensin II type 2 receptor in ischemia-induced angiogenesis in mice hindlimb.

    PubMed

    Silvestre, Jean-Sébastien; Tamarat, Radia; Senbonmatsu, Takaaki; Icchiki, Toshihiro; Ebrahimian, Teni; Iglarz, Marc; Besnard, Sandrine; Duriez, Micheline; Inagami, Tadashi; Lévy, Bernard I

    2002-05-31

    This study examined the potential role of angiotensin type 2 (AT(2)) receptor on angiogenesis in a model of surgically induced hindlimb ischemia. Ischemia was produced by femoral artery ligature in both wild-type and AT(2) gene-deleted mice (Agtr2(-)/Y). After 28 days, angiogenesis was quantitated by microangiography, capillary density measurement, and laser Doppler perfusion imaging. Protein levels of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), Bax, and Bcl-2 were determined by Western blot analysis in hindlimbs. The AT(2) mRNA level (assessed by semiquantitative RT-PCR) was increased in the ischemic hindlimb of wild-type mice. Angiographic vessel density and laser Doppler perfusion data showed significant improvement in ischemic/nonischemic leg ratio, 1.9- and 1.7-fold, respectively, in Agtr2(-)/Y mice compared with controls. In ischemic leg of Agtr2(-)/Y mice, revascularization was associated with an increase in the antiapoptotic protein content, Bcl-2 (211% of basal), and a decrease (60% of basal) in the number of cell death, determined by TUNEL method. Angiotensin II treatment (0.3 mg/kg per day) raised angiogenic score, blood perfusion, and both VEGF and eNOS protein content in ischemic leg of wild-type control but did not modulate the enhanced angiogenic response observed in untreated Agtr2(-)/Y mice. Finally, immunohistochemistry analysis revealed that VEGF was mainly localized to myocyte, whereas eNOS-positive staining was mainly observed in the capillary of ischemic leg of both wild-type and AT(2)-deficient mice. This study demonstrates for the first time that the AT(2) receptor subtype may negatively modulate ischemia-induced angiogenesis through an activation of the apoptotic process.

  11. Antibody-Induced Acetylcholine Receptor Clusters Inhabit Liquid-Ordered and Liquid-Disordered Domains

    PubMed Central

    Kamerbeek, Constanza B.; Borroni, Virginia; Pediconi, María F.; Sato, Satoshi B.; Kobayashi, Toshihide; Barrantes, Francisco J.

    2013-01-01

    The distribution of nicotinic acetylcholine receptor (AChR) clusters at the cell membrane was studied in CHO-K1/A5 cells using fluorescence microscopy. Di-4-ANEPPDHQ, a fluorescent probe that differentiates between liquid-ordered (Lo) and liquid-disordered (Ld) phases in model membranes, was used in combination with monoclonal anti-AChR antibody labeling of live cells, which induces AChR clustering. The so-called generalized polarization (GP) of di-4-ANEPPDHQ was measured in regions of the cell-surface membrane associated with or devoid of antibody-induced AChR clusters, respectively. AChR clusters were almost equally distributed between Lo and Ld domains, independently of receptor surface levels and agonist (carbamoylcholine and nicotine) or antagonist (α-bungarotoxin) binding. Cholesterol depletion diminished the cell membrane mean di-4-ANEPPDHQ GP and the number of AChR clusters associated with Ld membrane domains increased concomitantly. Depolymerization of the filamentous actin cytoskeleton by Latrunculin A had the opposite effect, with more AChR clusters associated with Lo domains. AChR internalized via small vesicles having lower GP and lower cholesterol content than the surface membrane. Upon cholesterol depletion, only 12% of the AChR-containing vesicles costained with the fluorescent cholesterol analog fPEG-cholesterol, i.e., AChR endocytosis was essentially dissociated from that of cholesterol. In conclusion, the distribution of AChR submicron-sized clusters at the cell membrane appears to be regulated by cholesterol content and cytoskeleton integrity. PMID:24094401

  12. Activation of retinoid X receptors induces apoptosis in HL-60 cell lines.

    PubMed Central

    Nagy, L; Thomázy, V A; Shipley, G L; Fésüs, L; Lamph, W; Heyman, R A; Chandraratna, R A; Davies, P J

    1995-01-01

    Retinoids induce myeloblastic leukemia (HL-60) cells to differentiate into granulocytes, which subsequently die by apoptosis. Retinoid action is mediated through at least two classes of nuclear receptors: retinoic acid receptors, which bind both all-trans retinoic acid and 9-cis retinoic acid, and retinoid X receptors, which bind only 9-cis retinoic acid. Using receptor-selective synthetic retinoids and HL-60 cell sublines with different retinoid responsiveness, we have investigated the contribution that each class of receptors makes to the processes of cellular differentiation and death. Our results demonstrate that ligand activation of retinoic acid receptors is sufficient to induce differentiation, whereas ligand activation of retinoid X receptors is essential for the induction of apoptosis in HL-60 cell lines. PMID:7791761

  13. Signal transduction induced in endothelial cells by growth factor receptors involved in angiogenesis

    PubMed Central

    Hofer, Erhard; Schweighofer, Bernhard

    2010-01-01

    Summary New vessel formation during development and in the adult is triggered by concerted signals of largely endothelial-specific receptors for ligands of the VEGF, angiopoietin and ephrin families. The signals and genes induced by these receptors operate in the context of additional signals transduced by non-endothelial specific growth factor receptors, inflammatory cytokine receptors as well as adhesion molecules. We summarize here available data on characteristic signaling of the VEGF receptor-2 and the current state of knowledge regarding the additional different receptor tyrosine kinases of the VEGF, Tie and Ephrin receptor families. Furthermore, the potential cross-talk with signals induced by other growth factors and inflammatory cytokines as well as the modulation by VE-cadherin is discussed. PMID:17334501

  14. The transient receptor potential ankyrin-1 mediates mechanical hyperalgesia induced by the activation of B1 receptor in mice.

    PubMed

    Meotti, Flavia Carla; Figueiredo, Cláudia Pinto; Manjavachi, Marianne; Calixto, João B

    2017-02-01

    The kinin receptor B1 and the transient receptor potential ankyrin 1 (TRPA1) work as initiators and gatekeepers of nociception and inflammation. This study reports that the nociceptive transmission induced by activation of B1 receptor is dependent on TRPA1 ion channel. The mechanical hyperalgesia was induced by intrathecal (i.t.) injection of B1 agonist des-Arginine(9)-bradykinin (DABK) or TRPA1 agonist cinnamaldehyde and was evaluated by the withdrawal response after von Frey Hair application in the hind paw. After behavioral experiments, lumbar spinal cord and dorsal root ganglia (DRG) were harvested to assess protein expression and mRNA by immunohistochemistry and real time-PCR, respectively. The pharmacological antagonism (HC030031) or the down-regulation of TRPA1 greatly inhibited the mechanical hyperalgesia induced by DABK. Intrathecal injection of DABK up regulated the ionized calcium binding adaptor molecule (Iba-1) in lumbar spinal cord (L5-L6); TRPA1 protein and mRNA in lumbar spinal cord; and B1 receptor mRNA in both lumbar spinal cord and DRG. The knockdown of TRPA1 prevented microglia activation induced by DABK. Furthermore, the mechanical hyperalgesia induced by either DABK or by cinnamaldehyde was significantly reduced by inhibition of cyclooxygenase (COX), protein kinase C (PKC) or phospholipase C (PLC). In summary, this study revealed that TRPA1 positively modulates the mechanical hyperalgesia induced by B1 receptor activation in the spinal cord and that the classical GPCR downstream molecules PLC, diacylglycerol (DAG), 3,4,5-inositide phosphate (IP3) and PKC are involved in the nociceptive transmission triggered by these two receptors.

  15. Blockade of the N-Methyl-D-Aspartate Glutamate Receptor Ameliorates Lipopolysaccharide-Induced Renal Insufficiency

    PubMed Central

    Huang, Ho-Shiang; Ma, Ming-Chieh

    2015-01-01

    N-methyl-D-aspartate (NMDA) receptor activation in rat kidney reduces renal perfusion and ultrafiltration. Hypoperfusion-induced ischemia is the most frequent cause of functional insufficiency in the endotoxemic kidney. Here, we used non-hypotensive rat model of lipopolysaccharide-induced endotoxemia to examine whether NMDA receptor hyperfunction contributes to acute kidney injury. Lipopolysaccharide-induced renal damage via increased enzymuria and hemodynamic impairments were ameliorated by co-treatment with the NMDA receptor blocker, MK-801. The NMDA receptor NR1 subunit in the rat kidney mainly co-localized with serine racemase, an enzyme responsible for synthesizing the NMDA receptor co-agonist, D-serine. The NMDA receptor hyperfunction in lipopolysaccharide-treated kidneys was demonstrated by NR1 and serine racemase upregulation, particularly in renal tubules, and by increased D-serine levels. Lipopolysaccharide also induced cell damage in cultured tubular cell lines and primary rat proximal tubular cells. This damage was mitigated by MK-801 and by small interfering RNA targeting NR1. Lipopolysaccharide increased cytokine release in tubular cell lines via toll-like receptor 4. The release of interleukin-1β from these cells are the most abundant. An interleukin-1 receptor antagonist not only attenuated cell death but also abolished lipopolysaccharide-induced NR1 and serine racemase upregulation and increases in D-serine secretion, suggesting that interleukin-1β-mediated NMDA receptor hyperfunction participates in lipopolysaccharide-induced tubular damage. The results of this study indicate NMDA receptor hyperfunction via cytokine effect participates in lipopolysaccharide-induced renal insufficiency. Blockade of NMDA receptors may represent a promising therapeutic strategy for the treatment of sepsis-associated renal failure. PMID:26133372

  16. Inflammation and peripheral 5-HT7 receptors: the role of 5-HT7 receptors in carrageenan induced inflammation in rats.

    PubMed

    Albayrak, Abdulmecit; Halici, Zekai; Cadirci, Elif; Polat, Beyzagul; Karakus, Emre; Bayir, Yasin; Unal, Deniz; Atasoy, Mustafa; Dogrul, Ahmet

    2013-09-05

    The aim of this study was: (1) to investigate possible role for 5-HT7 receptors in carrageenan induced inflammatory paw oedema in rats; (2) to determine the presence of 5-HT7 receptors in rat paw tissue; (3) to observe the effects of 5-HT7 receptor agonist and antagonist administration on inflammation; and (4) to determine a unique mechanism for inflammatory processes via 5-HT7 receptors. Effects of 5-HT7 receptor agonist, antagonist and indomethacin were investigated in carrageenan induced paw oedema in rats. Blood and tissue samples were collected and evaluated biochemically for serum cytokine levels, tissue oxidant-antioxidant balance and histopathologically for inflammatory cell accumulation. We performed Real Time PCR analyses for tissue 5-HT7 receptor and COX mRNA expressions. The 5-HT7 receptor agonist AS-19 exerted significant anti-inflammatory effect both alone and in combination with indomethacin. Antagonist, SB269970, did not affect inflammation alone but decreased the effects of agonist when co-administered. 5-HT7 mRNA levels were higher in the carrageenan group than healthy control. Carrageenan+indometacin group decreased the mRNA expression of 5-HT7 when compared to carrageenan group. While agonist administration decreased 5-HT7 mRNA expression when compared to carrageenan group. Agonist decreased paw COX expression. Agonist also decreased serum cytokine levels and tissue oxidative stress. In conclusion, this study demonstrated for the first time that 5-HT7 receptors are expressed in rat paw tissue and that this expression responds to inflammatory stimuli. The 5-HT7 receptor may be a promising new therapeutic target for prevention of inflammation and inflammatory disorders and may also provide a new glimpse into inflammation pathophysiology.

  17. Xenobiotic-induced hepatocyte proliferation associated with constitutive active/androstane receptor (CAR) or peroxisome proliferator-activated receptor α (PPARα) is enhanced by pregnane X receptor (PXR) activation in mice.

    PubMed

    Shizu, Ryota; Benoki, Satoshi; Numakura, Yuki; Kodama, Susumu; Miyata, Masaaki; Yamazoe, Yasushi; Yoshinari, Kouichi

    2013-01-01

    Xenobiotic-responsive nuclear receptors pregnane X receptor (PXR), constitutive active/androstane receptor (CAR) and peroxisome proliferator-activated receptor α (PPARα) play pivotal roles in the metabolic functions of the liver such as xenobiotics detoxification and energy metabolism. While CAR or PPARα activation induces hepatocyte proliferation and hepatocarcinogenesis in rodent models, it remains unclear whether PXR activation also shows such effects. In the present study, we have investigated the role of PXR in the xenobiotic-induced hepatocyte proliferation with or without CAR activation by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) and phenobarbital, or PPARα activation by Wy-14643 in mice. Treatment with TCPOBOP or phenobarbital increased the percentage of Ki-67-positive nuclei as well as mRNA levels of cell proliferation-related genes in livers as expected. On the other hand, treatment with the PXR activator pregnenolone 16α-carbonitrile (PCN) alone showed no such effects. Surprisingly, PCN co-treatment significantly augmented the hepatocyte proliferation induced by CAR activation with TCPOBOP or phenobarbital in wild-type mice but not in PXR-deficient mice. Intriguingly, PXR activation also augmented the hepatocyte proliferation induced by Wy-14643 treatment. Moreover, PCN treatment increased the RNA content of hepatocytes, suggesting the induction of G0/G1 transition, and reduced mRNA levels of Cdkn1b and Rbl2, encoding suppressors of cell cycle initiation. Our present findings indicate that xenobiotic-induced hepatocyte proliferation mediated by CAR or PPARα is enhanced by PXR co-activation despite that PXR activation alone does not cause the cell proliferation in mouse livers. Thus PXR may play a novel and unique role in the hepatocyte/liver hyperplasia upon exposure to xenobiotics.

  18. Effects of High Fat Feeding and Diabetes on Regression of Atherosclerosis Induced by Low-Density Lipoprotein Receptor Gene Therapy in LDL Receptor-Deficient Mice

    PubMed Central

    Willecke, Florian; Yuan, Chujun; Oka, Kazuhiro; Chan, Lawrence; Hu, Yunying; Barnhart, Shelley; Bornfeldt, Karin E.; Goldberg, Ira J.; Fisher, Edward A.

    2015-01-01

    We tested whether a high fat diet (HFD) containing the inflammatory dietary fatty acid palmitate or insulin deficient diabetes altered the remodeling of atherosclerotic plaques in LDL receptor knockout (Ldlr-/-) mice. Cholesterol reduction was achieved by using a helper-dependent adenovirus (HDAd) carrying the gene for the low-density lipoprotein receptor (Ldlr; HDAd-LDLR). After injection of the HDAd-LDLR, mice consuming either HFD, which led to insulin resistance but not hyperglycemia, or low fat diet (LFD), showed regression compared to baseline. However there was no difference between the two groups in terms of atherosclerotic lesion size, or CD68+ cell and lipid content. Because of the lack of effects of these two diets, we then tested whether viral-mediated cholesterol reduction would lead to defective regression in mice with greater hyperglycemia. In both normoglycemic and streptozotocin (STZ)-treated hyperglycemic mice, HDAd-LDLR significantly reduced plasma cholesterol levels, decreased atherosclerotic lesion size, reduced macrophage area and lipid content, and increased collagen content of plaque in the aortic sinus. However, reductions in anti-inflammatory and ER stress-related genes were less pronounced in STZ-diabetic mice compared to non-diabetic mice. In conclusion, HDAd-mediated Ldlr gene therapy is an effective and simple method to induce atherosclerosis regression in Ldlr-/- mice in different metabolic states. PMID:26046657

  19. Calcium Oxalate Induces Renal Injury through Calcium-Sensing Receptor

    PubMed Central

    Li, Xiaoran; Ma, Junhai; Shi, Wei; Su, Yu; Fu, Xu; Yang, Yanlin; Lu, Jianzhong

    2016-01-01

    Objective. To investigate whether calcium-sensing receptor (CaSR) plays a role in calcium-oxalate-induced renal injury. Materials and Methods. HK-2 cells and rats were treated with calcium oxalate (CaOx) crystals with or without pretreatment with the CaSR-specific agonist gadolinium chloride (GdCl3) or the CaSR-specific antagonist NPS2390. Changes in oxidative stress (OS) in HK-2 cells and rat kidneys were assessed. In addition, CaSR, extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal protein kinase (JNK), and p38 expression was determined. Further, crystal adhesion assay was performed in vitro, and the serum urea and creatinine levels and crystal deposition in the kidneys were also examined. Results. CaOx increased CaSR, ERK, JNK, and p38 protein expression and OS in vitro and in vivo. These deleterious changes were further enhanced upon pretreatment with the CaSR agonist GdCl3 but were attenuated by the specific CaSR inhibitor NPS2390 compared with CaOx treatment alone. Pretreatment with GdCl3 further increased in vitro and in vivo crystal adhesion and renal hypofunction. In contrast, pretreatment with NPS2390 decreased in vitro and in vivo crystal adhesion and renal hypofunction. Conclusions. CaOx-induced renal injury is related to CaSR-mediated OS and increased mitogen-activated protein kinase (MAPK) signaling, which subsequently leads to CaOx crystal adhesion. PMID:27965733

  20. Pregnane X receptor and drug-induced liver injury

    PubMed Central

    Wang, Yue-Ming; Chai, Sergio C.; Brewer, Christopher T; Chen, Taosheng

    2014-01-01

    Introduction The liver plays a central role in transforming and clearing foreign substances. The continuous exposure of the liver to xenobiotics sometimes leads to impaired liver function, referred to as drug-induced liver injury (DILI). The pregnane X receptor (PXR) tightly regulates the expression of genes in the hepatic drug-clearance system and its undesired activation plays a role in DILI. Areas covered This review focuses on the recent progress in understanding PXR-mediated DILI and highlights the efforts made to assess and manage PXR-mediated DILI during drug development. Expert opinion Future efforts are needed to further elucidate the mechanisms of PXR-mediated liver injury, including the epigenetic regulation and polymorphisms of PXR. Novel in vitro models containing functional PXR could improve our ability to predict and assess DILI during drug development. PXR inhibitors may provide chemical tools to validate the potential of PXR as a therapetic target and to develop drugs to be used in the clinic to manage PXR-mediated DILI. PMID:25252616

  1. Glyphosate induces human breast cancer cells growth via estrogen receptors.

    PubMed

    Thongprakaisang, Siriporn; Thiantanawat, Apinya; Rangkadilok, Nuchanart; Suriyo, Tawit; Satayavivad, Jutamaad

    2013-09-01

    Glyphosate is an active ingredient of the most widely used herbicide and it is believed to be less toxic than other pesticides. However, several recent studies showed its potential adverse health effects to humans as it may be an endocrine disruptor. This study focuses on the effects of pure glyphosate on estrogen receptors (ERs) mediated transcriptional activity and their expressions. Glyphosate exerted proliferative effects only in human hormone-dependent breast cancer, T47D cells, but not in hormone-independent breast cancer, MDA-MB231 cells, at 10⁻¹² to 10⁻⁶M in estrogen withdrawal condition. The proliferative concentrations of glyphosate that induced the activation of estrogen response element (ERE) transcription activity were 5-13 fold of control in T47D-KBluc cells and this activation was inhibited by an estrogen antagonist, ICI 182780, indicating that the estrogenic activity of glyphosate was mediated via ERs. Furthermore, glyphosate also altered both ERα and β expression. These results indicated that low and environmentally relevant concentrations of glyphosate possessed estrogenic activity. Glyphosate-based herbicides are widely used for soybean cultivation, and our results also found that there was an additive estrogenic effect between glyphosate and genistein, a phytoestrogen in soybeans. However, these additive effects of glyphosate contamination in soybeans need further animal study.

  2. Heterodimeric interaction between retinoid X receptor alpha and orphan nuclear receptor OR1 reveals dimerization-induced activation as a novel mechanism of nuclear receptor activation.

    PubMed Central

    Wiebel, F F; Gustafsson, J A

    1997-01-01

    OR1 is a member of the steroid/thyroid hormone nuclear receptor superfamily which has been described to mediate transcriptional responses to retinoids and oxysterols. On a DR4 response element, an OR1 heterodimer with the nuclear receptor retinoid X receptor alpha (RXR alpha) has been described to convey transcriptional activation in both the absence and presence of the RXR ligand 9-cis retinoic acid, the mechanisms of which have remained unclear. Here, we dissect the effects of RXR alpha and OR1 ligand-binding domain interaction on transcriptional regulation and the role of the respective carboxy-terminal activation domains (AF-2s) in the absence and presence of the RXR ligand, employing chimeras of the nuclear receptors containing the heterologous GAL4 DNA-binding domain as well as natural receptors. The results show that the interaction of the RXR and OR1 ligand-binding domains unleashes a transcription activation potential that is mainly dependent on the AF-2 of OR1, indicating that interaction with RXR activates OR1. This defines dimerization-induced activation as a novel function of heterodimeric interaction and mechanism of receptor activation not previously described for nuclear receptors. Moreover, we present evidence that activation of OR1 occurs by a conformational change induced upon heterodimerization with RXR. PMID:9199332

  3. Acetylcholine receptor-inducing factor from chicken brain increases the level of mRNA encoding the receptor. alpha. subunit

    SciTech Connect

    Harris, D.A.; Falls, D.L.; Dill-Devor, R.M.; Fischbach, G.D. )

    1988-03-01

    A 42-kDa glycoprotein isolated from chicken brain, referred to as acetylcholine receptor-inducing activity (ARIA), that stimulates the rate of incorporation of acetylcholine receptors into the surface of chicken myotubes may play a role in the nerve-induced accumulation of receptors at developing neuromuscular synapses. Using nuclease-protection assays, the authors have found that ARIA causes a 2- to 16-fold increase in the level of mRNA encoding the {alpha} subunit of the receptor, with little or no change in the levels of {gamma}- and {delta}-subunit messengers. ARIA also increases the amount of a putative nuclear precursor of {alpha}-subunit mRNA, consistent with an activation of gene transcription. These results suggest that the concentration of {alpha} subunit may limit the rate of biosynthesis of the acetylcholine receptors in chicken myotubes. They also indicate that neuronal factors can regulate the expression of receptor subunit genes in a selective manner. Tetrodotoxin, 8-bromo-cAMP, and forskolin also increase the amount of {alpha}-subunit mRNA, with little change in the amount of {gamma}- and {delta}-subunit mRNAs. Unlike ARIA, however, these agents have little effect on the concentration of the {alpha}-subunit nuclear precursor.

  4. Ligand-induced interaction between. alpha. - and. beta. -type platelet-derived growth factor (PDGF) receptors: Role of receptor heterodimers in kinase activation

    SciTech Connect

    Kanakaraj, P.; Raj, S.; Bishayee, S. ); Khan, S.A. )

    1991-02-19

    Two types of PDGF receptors have been cloned and sequenced. Both receptors are transmembrane glycoproteins with a ligand-stimulatable tyrosine kinase site. The authors have shown earlier that ligand-induced activation of the {beta}-type PDGF receptor is due to the conversion of the monomeric form of the receptor to the dimeric form. In the present studies, they have established the ligand-binding specificity of two receptor types and extended it further to investigate the ligand-induced association state of the {alpha}-receptor and the role of {alpha}-receptor in the activation of {beta}-receptor. These studies were conducted with cells that express one or the other type of PDGF receptor as well as with cells that express both types of receptors. Moreover, ligand-binding characteristics of the receptor were confirmed by immunoprecipitation of the receptor-{sup 125}I-PDGF covalent complex with type-specific anti-PDGF receptor antibodies. These studies revealed that all three isoforms of PDGF bind to {alpha}-receptor, and such binding leads to dimerization as well as activation of the receptor. In contrast, {beta}-receptor can be activated only by PDGF BB and not by PDGF AB or PDGF AA. However, by using antipeptide antibodies that are specific for {alpha}- or {beta}-type PDGF receptor, they demonstrated that in the presence of {alpha}-receptor, {beta}-receptor kinase can be activated by PDGF AB. They present here direct evidence that strongly suggests that such PDGF AB induced activation of {beta}-receptor is due to the formation of a noncovalently linked {alpha}-{beta} receptor heterodimer.

  5. Cellular androgen content influences enzalutamide agonism of F877L mutant androgen receptor

    PubMed Central

    Coleman, Daniel J.; Van Hook, Kathryn; King, Carly J.; Schwartzman, Jacob; Lisac, Robert; Urrutia, Joshua; Sehrawat, Archana; Woodward, Josha; Wang, Nicholas J.; Gulati, Roman; Thomas, George V.; Beer, Tomasz M.; Gleave, Martin; Korkola, James E.; Gao, Lina; Heiser, Laura M.; Alumkal, Joshi J.

    2016-01-01

    Prostate cancer is the most commonly diagnosed and second-most lethal cancer among men in the United States. The vast majority of prostate cancer deaths are due to castration-resistant prostate cancer (CRPC) – the lethal form of the disease that has progressed despite therapies that interfere with activation of androgen receptor (AR) signaling. One emergent resistance mechanism to medical castration is synthesis of intratumoral androgens that activate the AR. This insight led to the development of the AR antagonist enzalutamide. However, resistance to enzalutamide invariably develops, and disease progression is nearly universal. One mechanism of resistance to enzalutamide is an F877L mutation in the AR ligand-binding domain that can convert enzalutamide to an agonist of AR activity. However, mechanisms that contribute to the agonist switch had not been fully clarified, and there were no therapies to block AR F877L. Using cell line models of castration-resistant prostate cancer (CRPC), we determined that cellular androgen content influences enzalutamide agonism of mutant F877L AR. Further, enzalutamide treatment of AR F877L-expressing cell lines recapitulated the effects of androgen activation of F877L AR or wild-type AR. Because the BET bromodomain inhibitor JQ-1 was previously shown to block androgen activation of wild-type AR, we tested JQ-1 in AR F877L-expressing CRPC models. We determined that JQ-1 suppressed androgen or enzalutamide activation of mutant F877L AR and suppressed growth of mutant F877L AR CRPC tumors in vivo, demonstrating a new strategy to treat tumors harboring this mutation. PMID:27276681

  6. Monocyte chemoattractant protein-1-induced CCR2B receptor desensitization mediated by the G protein-coupled receptor kinase 2

    PubMed Central

    Aragay, A. M.; Mellado, M.; Frade, J. M. R.; Martin, A. M.; Jimenez-Sainz, M. C.; Martinez-A, C.; Mayor, F.

    1998-01-01

    Monocyte chemoattractant protein 1 (MCP-1) is a member of the chemokine cytokine family, whose physiological function is mediated by binding to the CCR2 and CCR4 receptors, which are members of the G protein-coupled receptor family. MCP-1 plays a critical role in both activation and migration of leukocytes. Rapid chemokine receptor desensitization is very likely essential for accurate chemotaxis. In this report, we show that MCP-1 binding to the CCR2 receptor in Mono Mac 1 cells promotes the rapid desensitization of MCP-1-induced calcium flux responses. This desensitization correlates with the Ser/Thr phosphorylation of the receptor and with the transient translocation of the G protein-coupled receptor kinase 2 (GRK2, also called β-adrenergic kinase 1 or βARK1) to the membrane. We also demonstrate that GRK2 and the uncoupling protein β-arrestin associate with the receptor, forming a macromolecular complex shortly after MCP-1 binding. Calcium flux responses to MCP-1 in HEK293 cells expressing the CCR2B receptor were also markedly reduced upon cotransfection with GRK2 or the homologous kinase GRK3. Nevertheless, expression of the GRK2 dominant-negative mutant βARK-K220R did not affect the initial calcium response, but favored receptor response to a subsequent challenge by agonists. The modulation of the CCR2B receptor by GRK2 suggests an important role for this kinase in the regulation of monocyte and lymphocyte response to chemokines. PMID:9501202

  7. The chemokine monocyte chemoattractant protein-1 induces functional responses through dimerization of its receptor CCR2

    PubMed Central

    Rodríguez-Frade, José Miguel; Vila-Coro, Antonio J.; Martín de Ana, Ana; Albar, Juan Pablo; Martínez-A., Carlos; Mellado, Mario

    1999-01-01

    Cytokines interact with hematopoietin superfamily receptors and stimulate receptor dimerization. We demonstrate that chemoattractant cytokines (chemokines) also trigger biological responses through receptor dimerization. Functional responses are induced after pairwise crosslinking of chemokine receptors by bivalent agonistic antichemokine receptor mAb, but not by their Fab fragments. Monocyte chemoattractant protein (MCP)-1-triggered receptor dimerization was studied in human embryonic kidney (HEK)-293 cells cotransfected with genes coding for the CCR2b receptor tagged with YSK or Myc sequences. After MCP-1 stimulation, immunoprecipitation with Myc-specific antibodies revealed YSK-tagged receptors in immunoblotting. Receptor dimerization also was validated by chemical crosslinking in both HEK-293 cells and the human monocytic cell line Mono Mac 1. Finally, we constructed a loss-of-function CCR2bY139F mutant that acted as a dominant negative, blocking signaling through the CCR2 wild-type receptor. This study provides functional support for a model in which the MCP-1 receptor is activated by ligand-induced homodimerization, allowing discussion of the similarities between bacterial and leukocyte chemotaxis. PMID:10097088

  8. Angiotensin protects cortical neurons from hypoxic-induced apoptosis via the angiotensin type 2 receptor.

    PubMed

    Grammatopoulos, Tom; Morris, Katherine; Ferguson, Paul; Weyhenmeyer, James

    2002-03-28

    The effects of angiotensin on mouse cortical neuronal cultures exposed to chemical-induced hypoxia was investigated. Cultures exposed to 10 mM sodium azide for 5 min showed a 17% increase in apoptosis when assayed 24 h postinsult. The N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 blocked sodium azide-induced cell death suggesting that the NMDA receptor contributes to the mediated cell death. Pretreatment of cultured neurons with angiotensin decreased sodium azide-induced apoptosis by 94%. When the AT(1) receptor was blocked by its receptor antagonist, losartan, angiotensin activation of the AT(2) receptor completely inhibited sodium azide-induced apoptosis. Pretreatment of neurons with the AT(2) receptor antagonist PD123319 resulted in angiotensin reducing sodium azide-induced apoptosis by 48%. These results demonstrate that angiotensin can significantly attenuate sodium azide-induced apoptosis primarily through activation of the AT(2) receptor and suggests that angiotensin may have a protective role in neurons undergoing ischemic injury.

  9. Cholecystokinin 1 receptor modulates the MEKK1-induced c-Jun trans-activation: structural requirements of the receptor

    PubMed Central

    Ibarz, Géraldine; Oiry, Catherine; Carnazzi, Eric; Crespy, Philippe; Escrieut, Chantal; Fourmy, Daniel; Galleyrand, Jean Claude; Gagne, Didier; Martinez, Jean

    2006-01-01

    In cells overexpressing active MEKK1 to enhance c-Jun trans-activation, expression of rat cholecystokinin 1 receptor increased the activity of c-Jun while in the same experimental conditions overexpression of mouse cholecystokinin 1 receptor repressed it. This differential trans-activation is specific, since it was not observed for either the other overexpressed kinases (MEK, PKA) or for other transcription factors (ATF2, ELK-1, CREB). This differential behaviour was also detected in a human colon adenocarcinoma cell-line naturally producing high levels of endogenous MEKK1. This differential behaviour between the two receptors on the MEKK1-induced c-Jun trans-activation was independent of the activation state of JNK, of the phosphorylation level of c-Jun and of its ability to bind its specific DNA responsive elements. Two amino acids (Val43 and Phe50 in the mouse cholecystokinin 1 receptor, replaced by Leu43 and Ileu50 in the rat cholecystokinin 1 receptor) localized in the first transmembrane domain were found to play a crucial role in this differential behaviour. MEKK1 probably activates a transcriptional partner of c-Jun whose activity is maintained or increased in the presence of the rat cholecystokinin 1 receptor but repressed in the presence of the mouse cholecystokinin 1 receptor. PMID:16491099

  10. Cholecystokinin 1 receptor modulates the MEKK1-induced c-Jun trans-activation: structural requirements of the receptor.

    PubMed

    Ibarz, Géraldine; Oiry, Catherine; Carnazzi, Eric; Crespy, Philippe; Escrieut, Chantal; Fourmy, Daniel; Galleyrand, Jean Claude; Gagne, Didier; Martinez, Jean

    2006-04-01

    In cells overexpressing active MEKK1 to enhance c-Jun trans-activation, expression of rat cholecystokinin 1 receptor increased the activity of c-Jun while in the same experimental conditions overexpression of mouse cholecystokinin 1 receptor repressed it. This differential trans-activation is specific, since it was not observed for either the other overexpressed kinases (MEK, PKA) or for other transcription factors (ATF2, ELK-1, CREB). This differential behaviour was also detected in a human colon adenocarcinoma cell-line naturally producing high levels of endogenous MEKK1. This differential behaviour between the two receptors on the MEKK1-induced c-Jun trans-activation was independent of the activation state of JNK, of the phosphorylation level of c-Jun and of its ability to bind its specific DNA responsive elements. Two amino acids (Val43 and Phe50 in the mouse cholecystokinin 1 receptor, replaced by Leu43 and Ileu50 in the rat cholecystokinin 1 receptor) localized in the first transmembrane domain were found to play a crucial role in this differential behaviour. MEKK1 probably activates a transcriptional partner of c-Jun whose activity is maintained or increased in the presence of the rat cholecystokinin 1 receptor but repressed in the presence of the mouse cholecystokinin 1 receptor.

  11. Differential subcellular distribution of rat brain dopamine receptors and subtype-specific redistribution induced by cocaine

    PubMed Central

    Voulalas, Pamela J.; Schetz, John; Undieh, Ashiwel S.

    2011-01-01

    We investigated the subcellular distribution of dopamine D1, D2 and D5 receptor subtypes in rat frontal cortex, and examined whether psychostimulant-induced elevation of synaptic dopamine could alter the receptor distribution. Differential detergent solubilization and density gradient centrifugation were used to separate various subcellular fractions, followed by semi-quantitative determination of the relative abundance of specific receptor proteins in each fraction. D1 receptors were predominantly localized to detergent-resistant membranes, and a portion of these receptors also floated on sucrose gradients. These properties are characteristic of proteins found in lipid rafts and caveolae. D2 receptors exhibited variable distribution between cytoplasmic, detergent-soluble and detergent-resistant membrane fractions, yet were not present in buoyant membranes. Most D5 receptor immunoreactivity was distributed into the cytoplasmic fraction, failing to sediment at forces up to 300,000g, while the remainder was localized to detergent-soluble membranes in cortex. D5 receptors were undetectable in detergent-resistant fractions or raft-like subdomains. Following daily cocaine administration for seven days, a significant portion of D1 receptors translocated from detergent-resistant membranes to detergent-soluble membranes and the cytoplasmic fraction. The distributions of D5 and D2 receptor subtypes were not significantly altered by cocaine treatment. These data imply that D5 receptors are predominantly cytoplasmic, D2 receptors are diffusely distributed within the cell, whereas D1 receptors are mostly localized to lipid rafts within the rat frontal cortex. Dopamine receptor subtype localization is susceptible to modulation by pharmacological manipulations that elevate synaptic dopamine, however the functional implications of such drug-induced receptor warrant further investigation. PMID:21236347

  12. Ligand-induced ErbB receptor dimerization

    PubMed Central

    Lemmon, Mark A.

    2009-01-01

    Structural studies have provided important new insights into how ligand binding promotes homodimerization and activation of the EGF receptor and the other members of the ErbB family or receptor tyrosine kinases. These structures have also suggested possible explanations for the unique properties of ErbB2, which has no known ligand and can cause cell transformation (and tumorigenesis) by simple overexpression. In parallel with these advances, studies of the EGF receptor at the cell surface increasingly argue that the structural studies are missing key mechanistic components. This is particularly evident in the structural prediction that EGF binding linked to receptor dimerization should be positively cooperative, whereas cell-surface EGF-binding studies suggest negative cooperativity. In this review, I summarize studies of ErbB receptor extracellular regions in solution and of intact receptors at the cell surface, and attempt to reconcile the differences suggested by the two approaches. By combining results obtained with receptor ‘parts’, it is qualitatively possible to explain some models for the properties of the whole receptor. These considerations underline the need to consider the intact ErbB receptors as intact allosterically regulated enzymes, and to combine cellular and structural studies into a complete picture. PMID:19038249

  13. A transgenic mouse model of neuroepithelial cell specific inducible overexpression of dopamine D1-receptor

    PubMed Central

    Fujimoto, Kumiko; Araki, Kiyomi; McCarthy, Deirdre M.; Sims, John R.; Ren, Jia-Qian; Zhang, Xuan; Bhide, Pradeep G.

    2010-01-01

    Dopamine and its receptors appear in the brain during early embryonic period suggesting a role for dopamine in brain development. In fact, dopamine receptor imbalance resulting from impaired physiological balance between D1- and D2-receptor activities can perturb brain development and lead to persisting changes in brain structure and function. Dopamine receptor imbalance can be produced experimentally using pharmacological or genetic methods. Pharmacological methods tend to activate or antagonize the receptors in all cell types. In the traditional gene knockout models the receptor imbalance occurs during development and also at maturity. Therefore, assaying the effects of dopamine imbalance on specific cell types (e.g. precursor versus postmitotic cells) or at specific periods of brain development (e.g. pre- or postnatal periods) is not feasible in these models. We describe a novel transgenic mouse model based on the tetracycline dependent inducible gene expression system in which dopamine D1-receptor transgene expression is induced selectively in neuroepithelial cells of the embryonic brain at experimenter-chosen intervals of brain development. In this model, doxycycline-induced expression of the transgene causes significant overexpression of the D1-receptor and significant reductions in the incorporation of the S-phase marker bromodeoxyuridine into neuroepithelial cells of the basal and dorsal telencephalon indicating marked effects on telencephalic neurogenesis. The D1-receptor overexpression occurs at higher levels in the medial ganglionic eminence than the lateral ganglionic eminence or cerebral wall. Moreover, although the transgene is induced selectively in the neuroepithelium, D1-receptor protein overexpression appears to persist in postmitotic cells. The mouse model can be modified for neuroepithelial cell-specific inducible expression of other transgenes or induction of the D1-receptor transgene in other cells in specific brain regions by crossbreeding

  14. TRPV1 and PLC Participate in Histamine H4 Receptor-Induced Itch

    PubMed Central

    Jian, Tunyu; Yang, Niuniu; Yang, Yan; Zhu, Chan; Yuan, Xiaolin; Yu, Guang; Wang, Changming; Wang, Zhongli; Shi, Hao; Tang, Min; He, Qian; Lan, Lei; Wu, Guanyi; Tang, Zongxiang

    2016-01-01

    Histamine H4 receptor has been confirmed to play a role in evoking peripheral pruritus. However, the ionic and intracellular signaling mechanism of activation of H4 receptor on the dorsal root ganglion (DRG) neurons is still unknown. By using cell culture and calcium imaging, we studied the underlying mechanism of activation of H4 receptor on the DRG neuron. Immepip dihydrobromide (immepip)—a histamine H4 receptor special agonist under cutaneous injection—obviously induced itch behavior of mice. Immepip-induced scratching behavior could be blocked by TRPV1 antagonist AMG9810 and PLC pathway inhibitor U73122. Application of immepip (8.3–50 μM) could also induce a dose-dependent increase in intracellular Ca2+ ([Ca2+]i) of DRG neurons. We found that 77.8% of the immepip-sensitized DRG neurons respond to the TRPV1 selective agonist capsaicin. U73122 could inhibit immepip-induced Ca2+ responses. In addition, immepip-induced [Ca2+]i increase could be blocked by ruthenium red, capsazepine, and AMG9810; however it could not be blocked by TRPA1 antagonist HC-030031. These results indicate that TRPV1 but not TRPA1 is the important ion channel to induce the DRG neurons' responses in the downstream signaling pathway of histamine H4 receptor and suggest that TRPV1 may be involved in the mechanism of histamine-induced itch response by H4 receptor activation. PMID:26819760

  15. TRPV1 and PLC Participate in Histamine H4 Receptor-Induced Itch.

    PubMed

    Jian, Tunyu; Yang, Niuniu; Yang, Yan; Zhu, Chan; Yuan, Xiaolin; Yu, Guang; Wang, Changming; Wang, Zhongli; Shi, Hao; Tang, Min; He, Qian; Lan, Lei; Wu, Guanyi; Tang, Zongxiang

    2016-01-01

    Histamine H4 receptor has been confirmed to play a role in evoking peripheral pruritus. However, the ionic and intracellular signaling mechanism of activation of H4 receptor on the dorsal root ganglion (DRG) neurons is still unknown. By using cell culture and calcium imaging, we studied the underlying mechanism of activation of H4 receptor on the DRG neuron. Immepip dihydrobromide (immepip)-a histamine H4 receptor special agonist under cutaneous injection-obviously induced itch behavior of mice. Immepip-induced scratching behavior could be blocked by TRPV1 antagonist AMG9810 and PLC pathway inhibitor U73122. Application of immepip (8.3-50 μM) could also induce a dose-dependent increase in intracellular Ca(2+) ([Ca(2+)]i) of DRG neurons. We found that 77.8% of the immepip-sensitized DRG neurons respond to the TRPV1 selective agonist capsaicin. U73122 could inhibit immepip-induced Ca(2+) responses. In addition, immepip-induced [Ca(2+)]i increase could be blocked by ruthenium red, capsazepine, and AMG9810; however it could not be blocked by TRPA1 antagonist HC-030031. These results indicate that TRPV1 but not TRPA1 is the important ion channel to induce the DRG neurons' responses in the downstream signaling pathway of histamine H4 receptor and suggest that TRPV1 may be involved in the mechanism of histamine-induced itch response by H4 receptor activation.

  16. Enhanced morphine-induced antinociception in histamine H3 receptor gene knockout mice.

    PubMed

    Mobarakeh, Jalal Izadi; Takahashi, Kazuhiro; Yanai, Kazuhiko

    2009-09-01

    Previous studies have implicated a potential role for histamine H3 receptor in pain processing. There have been conflicting data, however, on the roles of H3 receptors in pain perception, and little information is available about the role of spinal histamine H3 receptors in morphine-induced antinociception. In the present study we examined the role of histamine H3 receptor in morphine-induced antinociception using histamine H3 receptor knockout mice and a histamine H3 receptor antagonist. Anitinociception was evaluated by assays for four nociceptive stimuli: hot-plate, tail-flick, paw-withdrawal, and formalin tests. Antinociception induced by morphine (0.125 nmol/5 microl, i.t.) was significantly augmented in histamine H3 receptor knockout (-/-) mice compared to the wild-type (+/+) mice in all four assays of pain. Furthermore, the effect of intrathecally administered morphine with thioperamide, a histamine H3 antagonist, was examined in C57BL/6J mice. A low dose of i.t. administered thioperamide (0.125 nmol/5 microl) alone had no significant effect on the nociceptive response. In contrast, the combination of morphine (0.125 nmol/5 microl, i.t.) with the same dose of thioperamide resulted in a significant reduction in the pain-related behaviors in all four nociceptive tests. These results suggest that histamine exerts inhibitory effects on morphine-induced antinociception through H3 receptors at the spinal level.

  17. The atypical dopamine D1 receptor agonist SKF 83959 induces striatal Fos expression in rats.

    PubMed

    Wirtshafter, David; Osborn, Catherine V

    2005-12-28

    The effects of dopamine D1 receptor agonists are often presumed to result from an activation of adenylyl cyclase, but dopamine D1 receptors may also be linked to other signal transduction cascades and the relative importance of these various pathways is currently unclear. SKF 83959 is an agonist at dopamine D1 receptors linked to phospholipase C, but has been reported to be an antagonist at receptors linked to adenylyl cyclase. The current report demonstrates that SKF 83959 induces pronounced, nonpatchy, expression of the immediate-early gene product Fos in the striatum of intact rats which can be converted to a patchy pattern by pretreatment with the dopamine D2-like receptor agonist quinpirole. In rats with unilateral 6-hydroxydopamine lesions SKF 83959 induces strong behavioral rotation and a greatly potentiated Fos response. All of the responses to SKF 83959, in both intact and dopamine-depleted animals, can be blocked by pretreatment with the dopamine D1 receptor antagonist SCH-23390. In intact subjects, SKF 83959 induced Fos expression less potently than the standard dopamine D1 receptor agonist SKF 82958, but the two drugs were approximately equipotent in deinnervated animals. These results demonstrate for the first time that possession of full efficacy at dopamine D1 receptors linked to adenylyl cyclase is not a necessary requirement for the induction of striatal Fos expression in intact animals and suggest that alternative signal transduction pathways may play a role in dopamine agonist induced Fos expression, especially in dopamine-depleted subjects.

  18. The sigma receptor ligand (+/-)-BMY 14802 prevents methamphetamine-induced dopaminergic neurotoxicity via interactions at dopamine receptors.

    PubMed

    Terleckyj, I; Sonsalla, P K

    1994-04-01

    The possibility that compounds which interact with the putative sigma receptor might influence the dopaminergic neuropathology produced by the administration of methamphetamine (METH) to mice was investigated. (+/-)-BMY 14802 [alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine-butanol hydrochloride] attenuated METH-induced dopaminergic neuropathology whereas several other sigma-acting compounds such as R-(+)-3-(3-hydroxyphenyl)-N-propylpiperidine hydrochloride, 1,3-di-o-tolyl-guanidine, rimcazole, clorgyline or (-)-butaclamol did not alter neurotoxicity produced by this central nervous system stimulant. (-)-BMY 14802, which has a lower affinity for the sigma site than (+)-BMY 14802, was more potent than (+)-BMY 14802 in antagonizing METH-induced neuropathology. In addition, the ketone metabolite (BMY 14786; alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine-butanone hydrochloride), which is a major metabolite formed from (-)-BMY 14802, also attenuated the METH-induced effects. (+/-)-BMY 14802 pretreatment of mice prevented the reduction in D1 and D2 dopamine receptor number produced by the systemic administration of N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline and demonstrates that (+/-)-BMY 14802 and/or its metabolites interact with the dopamine receptor subtypes. Taken together, these findings suggest that the protective effect of (+/-)-BMY 14802 against METH-induced neuropathology is mediated, at least in part, through dopamine receptor antagonism. Furthermore, the failure of other sigma-acting compounds to alter METH-induced neurotoxicity indicates that the putative sigma receptor is unlikely to be an important mediator in this type of neuropathology.

  19. Brain CB₁ receptor expression following lipopolysaccharide-induced inflammation.

    PubMed

    Hu, H; Ho, W; Mackie, K; Pittman, Q J; Sharkey, K A

    2012-12-27

    Cannabinoid 1 receptors (CB(1)) are highly expressed on presynaptic terminals in the brain where they are importantly involved in the control of neurotransmitter release. Alteration of CB(1) expression is associated with a variety of neurological and psychiatric disorders. There is now compelling evidence that peripheral inflammatory disorders are associated with depression and cognitive impairments. These can be modeled in rodents with peripheral administration of lipopolysaccharide (LPS), but central effects of this treatment remain to be fully elucidated. As a reduction in endocannabinoid tone is thought to contribute to depression, we asked whether the expression of CB(1) in the CNS is altered following LPS treatment. CD1 mice received LPS (0.1-1mg/kg, ip) and 6h later activated microglial cells were observed only in circumventricular organs and only at the higher dose. At 24h, activated microglial cells were identified in other brain regions, including the hippocampus, a structure implicated in some mood disorders. Immunohistochemistry and real-time polymerase chain reaction (PCR) were utilized to evaluate the change of CB(1) expression 24h after inflammation. LPS induced an increase of CB(1) mRNA in the hippocampus and brainstem. Subsequent immunohistochemical analysis revealed reduced CB(1) in the hippocampus, especially in CA3 pyramidal layer. Analysis of co-localization with markers of excitatory and inhibitory terminals indicated that the decrease in CB(1) expression was restricted to glutamatergic terminals. Despite widespread microglial activation, these results suggest that peripheral LPS treatment leads to limited changes in CB(1) expression in the brain.

  20. Resistance to adenovirally induced hyperleptinemia in rats. Comparison of ventromedial hypothalamic lesions and mutated leptin receptors.

    PubMed Central

    Koyama, K; Shimabukuro, M; Chen, G; Wang, M Y; Lee, Y; Kalra, P S; Dube, M G; Kalra, S P; Newgard, C B; Unger, R H

    1998-01-01

    Leptin regulates appetite and body weight via hypothalamic targets, but it can act directly on cultured pancreatic islets to regulate their fat metabolism. To obtain in vivo evidence that leptin may act peripherally as well as centrally, we compared the effect of adenovirally induced hyperleptinemia on food intake, body weight, and islet fat content in ventromedial hypothalamic-lesioned (VMHL) rats, sham-lesioned (SL) controls, and Zucker Diabetic Fatty (ZDF) rats in which the leptin receptor is mutated. Infusion with recombinant adenovirus containing the rat leptin cDNA increased plasma leptin by approximately 20 ng/ml in VMHL and ZDF rats but had no effect on their food intake, body weight, or fat tissue weight. Caloric matching of hyperphagic VMHL rats to SL controls did not reduce their resistance to hyperleptinemia. Whereas prediabetic ZDF rats had a fourfold elevation in islet fat, in VMHL rats islet fat was normal and none of them became diabetic. Isolated islets from ZDF rats were completely resistant to the lipopenic action of leptin, while VMHL islets exhibited 50% of the normal response; caloric matching of VMHL rats to SL controls increased leptin responsiveness of their islets to 92% of controls. We conclude that leptin regulation of adipocyte fat requires an intact VMH but that islet fat content is regulated independently of the VMH. PMID:9710441

  1. Differential role of protein kinase C in desensitization of muscarinic receptor induced by phorbol esters and receptor agonists

    SciTech Connect

    Lai, Wi Sheung.

    1989-01-01

    PKC, a phorbol ester receptor, copurified with specific binding sites of ({sup 3}H)phorbol-12,13,-dibutyrate (({sup 3}H)PDBu). The specific binding of ({sup 3}H)PDBu to intact cells was saturable to a single class of binding sites. The PKC and phorbol ester receptors in N1E-115 cells can be down regulated by prolonged phorbol ester incubation. Phorbol 12-myristate 13-acetate (PMA) suppressed muscarinic receptor-mediated cyclic GMP response in a time-dependent and a concentration-dependent fashion and the suppressive effect of PMA could be attenuated by a protein kinase inhibitor, H-7, as well as by down-regulation of the PKC through long-term incubation with PDBu. Exposure of the cells to the muscarinic agonist carbamylcholine also desensitized subsequent CBC-mediated cyclic GMP response. However, pretreatment with carbamylcholine did not desensitize histamine-induced cyclic GMP formation while treatment with PMA suppressed this histamine-mediated response. Preincubation of the cells with CBC, but not with phorbol ester, resulted in down-regulation of muscarinic receptors. The loss of muscarinic receptors induced by agonist even occurred when the phosphoinositide hydrolysis response was suppressed.

  2. Determination of the Insoluble Aluminum Content in Steel Samples by Using Laser-Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Jia, Yunhai; Zhang, Yong; Sun, Nian

    2015-08-01

    The insoluble aluminum content in steel samples has a significant influence on the quality of the steel. In this paper, laser-induced breakdown spectroscopy (LIBS) is used to analyze the insoluble aluminum content in steel samples using a scanning mode. The average intensity plus 2.5 standard deviations was iterated and the final iteration value was taken as the threshold that distinguishes soluble and insoluble aluminum, and thus total and soluble aluminum content calibration curves were generated. Using the relevant total and soluble aluminum content calibration curves, the total and soluble aluminum contents in steel samples could be determined. The insoluble aluminum content could be determined by subtracting the soluble aluminum content from the total aluminum content. The insoluble aluminum content of standard samples and process product samples were determined using the present mathematical model; the results agreed well with the certified reference values. This method could be used to rapidly characterize the insoluble aluminum content in steel samples. supported by National Key Scientific Instrument and Equipment Development Project, China (No. 2012YQ20018208)

  3. Inhibition of Nicotinamide Phosphoribosyltransferase Induces Apoptosis in Estrogen Receptor-Positive MCF-7 Breast Cancer Cells

    PubMed Central

    Alaee, Mohammad; Khaghani, Shahnaz; Behroozfar, Kiarash; Hesari, Zahra; Ghorbanhosseini, Seyedeh Sara

    2017-01-01

    Purpose Tumor cells have increased turnover of nicotinamide adenine dinucleotide (NAD+), the main coenzyme in processes including adenosine diphosphate-ribosylation, deacetylation, and calcium mobilization. NAD+ is predominantly synthesized in human cells via the salvage pathway, with the first component being nicotinamide. Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme in this pathway, and its chemical inhibition by FK866 has elicited antitumor effects in several preclinical models of solid and hematologic cancers. However, its efficacy in estrogen receptor (ER)-positive and human epidermal growth factor receptor 2-positive breast cancer cells has not been previously investigated. In this study, we aimed to deplete the NAD+ content of MCF-7 cells, a model cell line for ER-positive breast cancer, by inhibiting NAMPT in order to evaluate downstream effects on p53 and its acetylation, p21 and Bcl-2-associated X protein (BAX) expression, and finally, apoptosis in MCF-7 breast cancer cells. Methods MCF-7 cells were cultured and treated with FK866. NAD+ levels in cells were determined colorimetrically. Levels of p53 and its acetylated form were determined by Western blotting. Expression of p21 and BAX was determined by real-time polymerase chain reaction. Finally, levels of apoptosis were assessed by flow cytometry using markers for annexin V and propidium iodide. Results FK866 treatment was able to increase p53 levels and acetylation, upregulate BAX and p21 expression, and induce apoptosis in MCF-7 cells. Addition of exogenous NAD+ to cells reversed these effects, suggesting that FK866 exerted its effects by depleting NAD+ levels. Conclusion Results showed that FK866 could effectively inhibit NAD+ biosynthesis and induce programmed cell death in MCF-7 cells, suggesting that NAMPT inhibitors may be useful for the treatment of ER-positive breast cancers. PMID:28382091

  4. Hypersensitivity Induced by Activation of Spinal Cord PAR2 Receptors Is Partially Mediated by TRPV1 Receptors

    PubMed Central

    Mrozkova, Petra; Spicarova, Diana; Palecek, Jiri

    2016-01-01

    Protease-activated receptors 2 (PAR2) and transient receptor potential vanilloid 1 (TRPV1) receptors in the peripheral nerve endings are implicated in the development of increased sensitivity to mechanical and thermal stimuli, especially during inflammatory states. Both PAR2 and TRPV1 receptors are co-expressed in nociceptive dorsal root ganglion (DRG) neurons on their peripheral endings and also on presynaptic endings in the spinal cord dorsal horn. However, the modulation of nociceptive synaptic transmission in the superficial dorsal horn after activation of PAR2 and their functional coupling with TRPV1 is not clear. To investigate the role of spinal PAR2 activation on nociceptive modulation, intrathecal drug application was used in behavioural experiments and patch-clamp recordings of spontaneous, miniature and dorsal root stimulation-evoked excitatory postsynaptic currents (sEPSCs, mEPSCs, eEPSCs) were performed on superficial dorsal horn neurons in acute rat spinal cord slices. Intrathecal application of PAR2 activating peptide SLIGKV-NH2 induced thermal hyperalgesia, which was prevented by pretreatment with TRPV1 antagonist SB 366791 and was reduced by protein kinases inhibitor staurosporine. Patch-clamp experiments revealed robust decrease of mEPSC frequency (62.8 ± 4.9%), increase of sEPSC frequency (127.0 ± 5.9%) and eEPSC amplitude (126.9 ± 12.0%) in dorsal horn neurons after acute SLIGKV-NH2 application. All these EPSC changes, induced by PAR2 activation, were prevented by SB 366791 and staurosporine pretreatment. Our results demonstrate an important role of spinal PAR2 receptors in modulation of nociceptive transmission in the spinal cord dorsal horn at least partially mediated by activation of presynaptic TRPV1 receptors. The functional coupling between the PAR2 and TRPV1 receptors on the central branches of DRG neurons may be important especially during different pathological states when it may enhance pain perception. PMID:27755539

  5. Effects of morphine on pentobarbital-induced responses in mu-opioid receptor knockout mice.

    PubMed

    Park, Y; Ho, I K; Jang, C G; Tanaka, S; Ma, T; Loh, H H; Ko, K H

    2001-03-15

    Effects of morphine on the potentiation of pentobarbital-induced responses were investigated using mu-opioid receptor knockout mice. The duration of loss of righting reflex, hypothermia, and loss of motor coordination induced by pentobarbital were measured after pretreatment with either morphine or saline. Morphine pretreatment failed to show potentiation of both pentobarbital-induced loss of righting reflex and hypothermia in mu-opioid receptor knockout mice, while it significantly potentiated these responses in the wild-type controls. For motor incoordination test, morphine potentiated pentobarbital-induced motor incoordination in the wild-type mice. However, morphine may have opposite effects in the mu-opioid receptor knockout mice. These results demonstrate that synergism between morphine and pentobarbital is not detected in mu-opioid receptor knockout mice and that potentiation of pentobarbital-induced loss of righting reflex and hypothermia by morphine is mediated through mu-opioid receptor. It was interesting to note that pentobarbital-induced decrease in body temperature was less severe in mu-opioid receptor knockout mice than in wild-type mice.

  6. The effects of sigma (σ1) receptor-selective ligands on muscarinic receptor antagonist-induced cognitive deficits in mice

    PubMed Central

    Malik, Maninder; Rangel-Barajas, Claudia; Sumien, Nathalie; Su, Chang; Singh, Meharvan; Chen, Zhenglan; Huang, Ren-Qi; Meunier, Johann; Maurice, Tangui; Mach, Robert H; Luedtke, Robert R

    2015-01-01

    Background and Purpose Cognitive deficits in patients with Alzheimer's disease, Parkinson's disease, traumatic brain injury and stroke often involve alterations in cholinergic signalling. Currently available therapeutic drugs provide only symptomatic relief. Therefore, novel therapeutic strategies are needed to retard and/or arrest the progressive loss of memory. Experimental Approach Scopolamine-induced memory impairment provides a rapid and reversible phenotypic screening paradigm for cognition enhancement drug discovery. Male C57BL/6J mice given scopolamine (1 mg·kg−1) were used to evaluate the ability of LS-1–137, a novel sigma (σ1) receptor-selective agonist, to improve the cognitive deficits associated with muscarinic antagonist administration. Key Results LS-1–137 is a high-affinity (Ki = 3.2 nM) σ1 receptor agonist that is 80-fold selective for σ1, compared with σ2 receptors. LS-1–137 binds with low affinity at D2-like (D2, D3 and D4) dopamine and muscarinic receptors. LS-1–137 was found to partially reverse the learning deficits associated with scopolamine administration using a water maze test and an active avoidance task. LS-1–137 treatment was also found to trigger the release of brain-derived neurotrophic factor from rat astrocytes. Conclusions and Implications The σ1 receptor-selective compound LS-1–137 may represent a novel candidate cognitive enhancer for the treatment of muscarinic receptor-dependent cognitive deficits. PMID:25573298

  7. Differences in the progesterone receptor contents between familial breast cancers and sporadic breast cancers stratified by patient age.

    PubMed

    Fukutomi, T; Akashi-Tanaka, S

    2001-01-01

    In the present study, we investigated the estrogen (ER) and progesterone receptor (PR) contents of familial breast cancers (FBCs) and compared the findings with those of sporadic breast cancers., stratified by the patients' age. To evaluate the hormone receptor contents of Japanese FBCs, we collected a consecutive series of 250 FBCs and 2,533 sporadic breast cancers (SBCs). These patients were divided into the three groups stratified by the patients' age at initial surgery (group I, under 40 years old; group II, 40-60 years old; group III, over 60 years old). The clinicopathological features of FBCs and SBCs, including ERs and PRs, were analyzed for each group. In all age groups, the PR contents of FBCs were significantly lower than those of SBCs, particularly for group III. In FBCs, the PR content was significantly lower in group III than in groups I or II. In addition, there was a nonsignificant trend towards a high frequency of ER-positive, PR-negative tumors in FBC patients aged 60 years and over. These data indicate that the loss of ER function and/or loss of binding capacity of PR to progesterone was associated with some late-onset FBCS.

  8. Increased metallothionein content in rat liver induced by x irradiation and exposure to high oxygen tension

    SciTech Connect

    Shiraishi, N.; Aono, K.; Utsumi, K.

    1983-08-01

    X irradiation and exposure to high oxygen tension are known to induce lipid peroxidation. The effects of these stresses on hepatic content of metallothionein, which may be involved in the regulation of zinc and copper metabolism, have been studied. The amount of metallothionein in rat liver was increased 11-fold by a high dose of X irradiation (1000 R). Increased metallothionein content (about 15 times) was also observed in liver of rats exposed to high oxygen tension for 3 days.

  9. [Effects of agonists and antagonists of benzodiazepine, GABA and NMDA receptors, on caffeine-induced seizures in mice].

    PubMed

    Inano, S

    1992-08-01

    In mice, tonic convulsive seizure induced by intravenous administration of caffeine (adenosine A1, A2 receptors antagonist) was significantly potentiated by any one of L-PIA (adenosine A1 receptor agonist), NECA (adenosine A2 receptor agonist) and 2-ClAd (adenosine A1, A2 receptors agonist). The caffeine-induced seizure was unaffected by diazepam (benzodiazepine receptor agonist), but was inhibited by Ro 15-1788 (antagonist or partial agonist). beta-DMCM (antagonist or inverse agonist) increased the seizure. Muscimol (GABA-a receptor agonist), baclofen (GABA-b receptor agonist) and AOAA (GABA transaminase inhibitor) did not show significant effect on caffeine-induced convulsion. Bicuculline (GABA-a receptor antagonist) and picrotoxin (chloride channel blocker) significantly potentiated the convulsion at the doses which did not induce it. Caffeine-induced convulsion was potentiated by NMDA with its non-convulsive dose. CPP (competitive NMDA receptor antagonist) and MK-801 (non-competitive NMDA receptor antagonist) significantly inhibited the seizures. These results suggest that caffeine-induced seizure is not caused by blockade of adenosine receptors. Caffeine may act to beta-carboline sensitive benzodiazepine receptor (Type 1) which has no linkage with GABA-a receptor. Furthermore, it is implied that caffeine plays some role at NMDA receptor calcium ion channel complex.

  10. Inhibitory effect of CXC chemokine receptor 4 antagonist AMD3100 on bleomycin induced murine pulmonary fibrosis.

    PubMed

    Song, Jeong Sup; Kang, Chun Mi; Kang, Hyeon Hui; Yoon, Hyung Kyu; Kim, Young Kyoon; Kim, Kwan Hyung; Moon, Hwa Sik; Park, Sung Hak

    2010-06-30

    CXC chemokine receptor 4 (CXCR4), which binds the stromal cell-derived factor-1 (SDF-1), has been shown to play a critical role in mobilizing the bone marrow (BM)-derived stem cells and inflammatory cells. We studied the effects of AMD3100, CXCR4 antagonist, on a murine bleomycin-induced pulmonary fibrosis model. Treatment of mice with AMD3100 in bleomycin-treated mice resulted in the decrease of SDF-1 in bronchoalveolar lavage (BAL) fluids at an early stage and was followed by the decrease of fibrocytes in the lung. AMD3100 treatment decreased the SDF-1 mRNA expression, fibrocyte numbers in the lung at an early stage (day 3) and CXCR4 expression at the later stage (day 7 and 21) after bleomycin injury. The collagen content and pulmonary fibrosis were significantly attenuated by AMD3100 treatment in later stage of bleomycin injury. AMD3100 treatment also decreased the murine mesenchymal and hematopoietic stem cell chemotaxis when either in the stimulation with bleomycin treated lung lysates or SDF-1 in vitro. In BM stem cell experiments, the phosphorylation of p38 MAPK which was induced by SDF-1 was significantly blocked by addition of AMD3100. Our data suggest that AMD3100 might be effective in preventing the pulmonary fibrosis by inhibiting the fibrocyte mobilization to the injured lung via blocking the SDF-1/CXCR4 axis.

  11. Binding site and subclass specificity of the herpes simplex virus type 1-induced Fc receptor.

    PubMed Central

    Wiger, D; Michaelsen, T E

    1985-01-01

    Immunoglobulin Fc-binding activity was detected by indirect immunofluorescence employing fluorochrome conjugated F(ab')2 antibody fragments on acetone-fixed cell cultures infected with herpes simplex virus type 1 (HSV-1). Using this method the Fc receptor-like activity seemed to be restricted to the IgG class of human immunoglobulins. While IgG1, IgG2, and IgG4 myeloma proteins bind to this putative Fc gamma receptor at a concentration of 0.002 mg/ml, IgG3 myeloma proteins were without activity at 0.1 mg/ml. The binding activity was associated with the Fc fragments of IgG, while the pFc' fragments of IgG appeared to be unable to bind in this assay system. The reactivity and specificity of the HSV-1 Fc receptor was independent of both the type of tissue culture cells used and the strain of HSV-1 inducing the Fc receptor-like activity. The HSV-1-induced Fc receptor has a similar specificity for human immunoglobulin class and subclasses as staphylococcal Protein A. However, these two Fc receptors exhibit at least one striking difference. The IgG3 G3m(st) protein which binds to Protein A does not bind to HSV-1-induced Fc receptor. A possible reaction site for the HSV-1 Fc receptor on IgG could be at or near Asp 276. Images Figure 1 PMID:2982735

  12. Role of the basolateral amygdala dopamine receptors in arachidonylcyclopropylamide-induced fear learning deficits.

    PubMed

    Nasehi, Mohammad; Hajian, Maryam; Ebrahimi-Ghiri, Mohaddeseh; Zarrindast, Mohammad-Reza

    2016-01-01

    There is much evidence suggesting that the mesoamygdala dopaminergic (DAergic) system plays a crucial role in the formation and expression of fear conditioning, with both D1 and D2 receptors being involved. In addition, cannabinoid CB1 receptor (CB1R) signaling modulates DAergic pathways. The present study sought to determine the involvement of basolateral amygdala (BLA) dopamine receptors in arachidonylcyclopropylamide (ACPA)-induced fear learning deficits. Context- and tone-dependent fear conditioning in adult male NMRI mice was evaluated. Pre-training intraperitoneal administration of ACPA (0.1 mg/kg) decreased the percentage of freezing in context- or tone-dependent fear conditioning, suggesting an acquisition impairment. Pre-training intra-BLA microinjection of a subthreshold dose of SKF38393 (D1-like receptor agonist), SCH23390 (D1-like receptor antagonist), quinpirole (D2-like receptor agonist), or sulpiride (D2-like receptor antagonist) did not alter the context-dependent fear learning deficit induced by ACPA, while SKF38393 or quinpirole restored ACPA effect on tone-dependent fear learning. Moreover, SKF38393 (1 μg/mouse), SCH23390 (0.04 and 0.08 μg/mouse), or quinpirole (0.1 μg/mouse) all impaired context-dependent fear learning. It is concluded that D1 or D2 dopamine (DA) receptor activation restores tone- but not context-dependent fear learning deficit induced by CB1 activation using ACPA.

  13. Inducible viral receptor, A possible concept to induce viral protection in primitive immune animals

    PubMed Central

    2011-01-01

    A pseudolysogen (PL) is derived from the lysogenic Vibrio harveyi (VH) which is infected with the VHS1 (Vibrio harveyi Siphoviridae-like 1) bacteriophage. The lysogenic Vibrio harveyi undergoes an unequivalent division of the extra-chromosomal VHS1 phage genome and its VH host chromosome and produces a true lysogen (TL) and pseudolysogen (PL). The PL is tolerant to super-infection of VHS1, as is of the true lysogen (TL), but the PL does not contain the VHS1 phage genome while the TL does. However, the PL can become susceptible to VHS1 phage infection if the physiological state of the PL is changed. It is postulated that this is due to a phage receptor molecule which can be inducible to an on-and-off regulation influence by an alternating condition of the bacterial host cell. This characteristic of the PL leads to speculate that this phenomenon can also occur in high organisms with low immunity such as shrimp. This article proposes a hypothesis that the viral receptor molecule on the target cell can play a crucial role in which the invertebrate aquaculture animals can become tolerant to viral infection. A possible mechanism may be that the target cell disrupts the viral receptor molecule to prevent super infection. This concept can explain a mechanism for the prevention of viral infection in invertebrate animals which do not have acquired immunity in response to pathogens. It can guide us to develop a mechanism of immunity to viral infection in low-evolved-immune animals. Also, it can be an additional mechanism that exists in high immune organism, as in human for the prevention of viral infection PMID:21711515

  14. Potentiation of morphine-induced mechanical antinociception by σ₁ receptor inhibition: role of peripheral σ₁ receptors.

    PubMed

    Sánchez-Fernández, Cristina; Nieto, Francisco Rafael; González-Cano, Rafael; Artacho-Cordón, Antonia; Romero, Lucía; Montilla-García, Ángeles; Zamanillo, Daniel; Baeyens, José Manuel; Entrena, José Manuel; Cobos, Enrique José

    2013-07-01

    We studied the modulation of morphine-induced mechanical antinociception and side effects by σ₁ receptor inhibition. Both wild-type (WT) and σ₁ receptor knockout (σ₁-KO) mice showed similar responses to paw pressure (100-600 g). The systemic (subcutaneous) or local (intraplantar) administration of σ₁ antagonists (BD-1063, BD-1047, NE-100 and S1RA) was devoid of antinociceptive effects in WT mice. However, σ₁-KO mice exhibited an enhanced mechanical antinociception in response to systemic morphine (1-16 mg/kg). Similarly, systemic treatment of WT mice with σ₁ antagonists markedly potentiated morphine-induced antinociception, and its effects were reversed by the selective σ₁ agonist PRE-084. Although the local administration of morphine (50-200 μg) was devoid of antinociceptive effects in WT mice, it induced dose-dependent antinociception in σ₁-KO mice. This effect was limited to the injected paw. Enhancement of peripheral morphine antinociception was replicated in WT mice locally co-administered with σ₁ antagonists and the opioid. None of the σ₁ antagonists tested enhanced morphine-antinociception in σ₁-KO mice, confirming a σ₁-mediated action. Morphine-induced side-effects (hyperlocomotion and inhibition of gastrointestinal transit) were unaltered in σ₁-KO mice. These results cannot be explained by a direct interaction of σ₁ ligands with μ-opioid receptors or adaptive changes of μ-receptors in σ₁-KO mice, given that [(3)H]DAMGO binding in forebrain, spinal cord, and hind-paw skin membranes was unaltered in mutant mice, and none of the σ₁ drugs tested bound to μ-opioid receptors. These results show that σ₁ receptor inhibition potentiates morphine-induced mechanical analgesia but not its acute side effects, and that this enhanced analgesia can be induced at peripheral level.

  15. Heregulin-Induced Growth Factor Receptor Signaling and Breast Carcinogenesis

    DTIC Science & Technology

    1995-07-17

    and/or signaling of erbB family receptors plays a significant role in tumors of mammary or neuroectodermal origin [Reviewed in Hynes and Stern, 1994...MDA- MB-231 human mammary tumor cell line [Holmes, et al., 1992], suggesting that NRGs establish or maintain the growth-transformed phenotype. NRG also...et al., 1992] the in vitro proliferation of human mammary tumor cells, which frequently overexpress erbB 5 family receptors [Reviewed in Hynes and

  16. Spinal 5-HT7 receptors induce phrenic motor facilitation via EPAC-mTORC1 signaling

    PubMed Central

    Fields, D. P.; Springborn, S. R.

    2015-01-01

    Spinal serotonin type 7 (5-HT7) receptors elicit complex effects on motor activity. Whereas 5-HT7 receptor activation gives rise to long-lasting phrenic motor facilitation (pMF), it also constrains 5-HT2 receptor-induced pMF via “cross-talk inhibition.” We hypothesized that divergent cAMP-dependent signaling pathways give rise to these distinct 5-HT7 receptor actions. Specifically, we hypothesized that protein kinase A (PKA) mediates cross-talk inhibition of 5-HT2 receptor-induced pMF whereas 5-HT7 receptor-induced pMF results from exchange protein activated by cAMP (EPAC) signaling. Anesthetized, paralyzed, and ventilated rats receiving intrathecal (C4) 5-HT7 receptor agonist (AS-19) injections expressed pMF for >90 min, an effect abolished by pretreatment with a selective EPAC inhibitor (ESI-05) but not a selective PKA inhibitor (KT-5720). Furthermore, intrathecal injections of a selective EPAC activator (8-pCPT-2′-Me-cAMP) were sufficient to elicit pMF. Finally, spinal mammalian target of rapamycin complex-1 (mTORC1) inhibition via intrathecal rapamycin abolished 5-HT7 receptor- and EPAC-induced pMF, demonstrating that spinal 5-HT7 receptors elicit pMF by an EPAC-mTORC1 signaling pathway. Thus 5-HT7 receptors elicit and constrain spinal phrenic motor plasticity via distinct signaling mechanisms that diverge at cAMP (EPAC vs. PKA). Selective manipulation of these molecules may enable refined regulation of serotonin-dependent spinal motor plasticity for therapeutic advantage. PMID:26269554

  17. Spinal 5-HT7 receptors induce phrenic motor facilitation via EPAC-mTORC1 signaling.

    PubMed

    Fields, D P; Springborn, S R; Mitchell, G S

    2015-09-01

    Spinal serotonin type 7 (5-HT7) receptors elicit complex effects on motor activity. Whereas 5-HT7 receptor activation gives rise to long-lasting phrenic motor facilitation (pMF), it also constrains 5-HT2 receptor-induced pMF via "cross-talk inhibition." We hypothesized that divergent cAMP-dependent signaling pathways give rise to these distinct 5-HT7 receptor actions. Specifically, we hypothesized that protein kinase A (PKA) mediates cross-talk inhibition of 5-HT2 receptor-induced pMF whereas 5-HT7 receptor-induced pMF results from exchange protein activated by cAMP (EPAC) signaling. Anesthetized, paralyzed, and ventilated rats receiving intrathecal (C4) 5-HT7 receptor agonist (AS-19) injections expressed pMF for >90 min, an effect abolished by pretreatment with a selective EPAC inhibitor (ESI-05) but not a selective PKA inhibitor (KT-5720). Furthermore, intrathecal injections of a selective EPAC activator (8-pCPT-2'-Me-cAMP) were sufficient to elicit pMF. Finally, spinal mammalian target of rapamycin complex-1 (mTORC1) inhibition via intrathecal rapamycin abolished 5-HT7 receptor- and EPAC-induced pMF, demonstrating that spinal 5-HT7 receptors elicit pMF by an EPAC-mTORC1 signaling pathway. Thus 5-HT7 receptors elicit and constrain spinal phrenic motor plasticity via distinct signaling mechanisms that diverge at cAMP (EPAC vs. PKA). Selective manipulation of these molecules may enable refined regulation of serotonin-dependent spinal motor plasticity for therapeutic advantage.

  18. Changes in the content of sex steroid hormone receptors in the growing and regressing ovaries of Gallus domesticus during development.

    PubMed

    González-Morán, María Genoveva; González-Arenas, Aliesha; Germán-Castelán, Liliana; Camacho-Arroyo, Ignacio

    2013-08-01

    Sex steroids participate in the regulation of reproduction in female chickens. In this work, we determined the content of androgen receptor (AR), intracellular progesterone receptor isoforms (PR-A and PR-B), membrane progesterone receptor γ (mPRγ) and estrogen receptor α (ER-α) in the left growing and right regressing ovaries of Gallus domesticus from 13-day-old chicken embryos to 1-month-old chickens by western blot analysis. A marked difference in the morphological characteristics of the left and the right ovaries during development was observed. Results show a higher content of AR in the left ovary than in the right one in all ages. In the left ovary, the highest content of AR was observed on day 13 of embryonic development, and diminished with age. In the right ovary, AR was expressed from day 13 of embryonic development to 1-day-old, and became undetectable at 1-week and 1-month-old. In the left ovary, PR isoforms were not detected on day 13 of embryonic development, but they presented a marked expression after hatching. In the right ovary, the highest expression of both PR isoforms was found on 1-day-old, and significantly decreased with age. PR-B was the predominant isoform on 1-day and 1-month old in the left ovary, whereas PR-A was the predominant one on day 13 of embryonic development in the right ovary. Interestingly, mPRγ was detected at 1-week and 1-month-old in the left ovary meanwhile in the right ovary, it was detected from day 13 of embryonic development to 1-day-old. ER-α was only detected in the left ovary from day 13 to 1-week-old, while in 1-month-old chickens, it was expressed in both ovaries. In the left ovary, ER-α content was lower from 1-day to 1-month-old as compared with day 13 of embryonic development. Our results demonstrate a differential expression of sex steroid hormone receptors between the left growing and the right regressing ovary, and throughout chickens' age; and this is the first report about mPR expression in birds.

  19. Adenosine A2 receptors modulate haloperidol-induced catalepsy in rats.

    PubMed

    Mandhane, S N; Chopde, C T; Ghosh, A K

    1997-06-11

    The effect of adenosine A1 and A2 receptor agonists and antagonists was investigated on haloperidol-induced catalepsy in rats. Pretreatment (i.p.) with the non-selective adenosine receptor antagonist, theophylline, or the selective adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX), significantly reversed haloperidol-induced catalepsy, whereas the selective adenosine A1 receptor antagonists, 8-phenyltheophylline and 8-cyclopentyl-1,3-dipropylxanthine produced no effect. Similar administration of the adenosine A2 receptor agonists, 5'-(N-cyclopropyl)-carboxamidoadenosine and 5'-N-ethylcarboxamidoadenosine (NECA), and the mixed agonists with predominantly A1 site of action, N6-(2-phenylisopropyl) adenosine or 2-chloroadenosine, potentiated haloperidol-induced catalepsy. Higher doses of the adenosine agonists produced catalepsy when given alone. However, N6-cyclopentyladenosine, a highly selective adenosine A1 receptor agonist, was ineffective in these respects. The per se cataleptic effect of adenosine agonists was blocked by DMPX and the centrally acting anticholinergic agent, scopolamine. Scopolamine also attenuated the potentiation of haloperidol-induced catalepsy by adenosine agonists. Further, i.c.v. administration of NECA and DMPX produced a similar effect as that produced after their systemic administration. These findings demonstrate the differential influence of adenosine A1 and A2 receptors on haloperidol-induced catalepsy and support the hypothesis that the functional interaction between adenosine and dopamine mechanisms might occur through adenosine A2 receptors at the level of cholinergic neurons. The results suggest that adenosine A2, but not A1, receptor antagonists may be of potential use in the treatment of Parkinson's disease.

  20. Pharmacological activation of 5-HT7 receptors reduces nerve injury-induced mechanical and thermal hypersensitivity.

    PubMed

    Brenchat, Alex; Nadal, Xavier; Romero, Luz; Ovalle, Sergio; Muro, Asunción; Sánchez-Arroyos, Ricard; Portillo-Salido, Enrique; Pujol, Marta; Montero, Ana; Codony, Xavier; Burgueño, Javier; Zamanillo, Daniel; Hamon, Michel; Maldonado, Rafael; Vela, José Miguel

    2010-06-01

    The involvement of the 5-HT(7) receptor in nociception and pain, particularly chronic pain (i.e., neuropathic pain), has been poorly investigated. In the present study, we examined whether the 5-HT(7) receptor participates in some modulatory control of nerve injury-evoked mechanical hypersensitivity and thermal (heat) hyperalgesia in mice. Activation of 5-HT(7) receptors by systemic administration of the selective 5-HT(7) receptor agonist AS-19 (1 and 10mg/kg) exerted a clear-cut reduction of mechanical and thermal hypersensitivities that were reversed by co-administering the selective 5-HT(7) receptor antagonist SB-258719. Interestingly, blocking of 5-HT(7) receptors with SB-258719 (2.5 and 10mg/kg) enhanced mechanical (but not thermal) hypersensitivity in nerve-injured mice and induced mechanical hypersensitivity in sham-operated mice. Effectiveness of the treatment with a 5-HT(7) receptor agonist was maintained after repeated systemic administration: no tolerance to the antiallodynic and antihyperalgesic effects was developed following treatment with the selective 5-HT(7) receptor agonist E-57431 (10mg/kg) twice daily for 11 days. The 5-HT(7) receptor co-localized with GABAergic cells in the dorsal horn of the spinal cord, suggesting that the activation of spinal inhibitory GABAergic interneurons could contribute to the analgesic effects of 5-HT(7) receptor agonists. In addition, a significant increase of 5-HT(7) receptors was found by immunohistochemistry in the ipsilateral dorsal horn of the spinal cord after nerve injury, suggesting a "pain"-triggered regulation of receptor expression. These results support the idea that the 5-HT(7) receptor subtype is involved in the control of pain and point to a new potential use of 5-HT(7) receptor agonists for the treatment of neuropathic pain.

  1. Gastrin and D1 dopamine receptor interact to induce natriuresis and diuresis.

    PubMed

    Chen, Yue; Asico, Laureano D; Zheng, Shuo; Villar, Van Anthony M; He, Duofen; Zhou, Lin; Zeng, Chunyu; Jose, Pedro A

    2013-11-01

    Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl. Gastrin is the major gastrointestinal hormone taken up by renal proximal tubule (RPT) cells. We hypothesized that renal gastrin and dopamine receptors interact to synergistically increase sodium excretion, an impaired interaction of which may be involved in the pathogenesis of hypertension. In Wistar-Kyoto rats, infusion of gastrin induced natriuresis and diuresis, which was abrogated in the presence of a gastrin (cholecystokinin B receptor [CCKBR]; CI-988) or a D1-like receptor antagonist (SCH23390). Similarly, the natriuretic and diuretic effects of fenoldopam, a D1-like receptor agonist, were blocked by SCH23390, as well as by CI-988. However, the natriuretic effects of gastrin and fenoldopam were not observed in spontaneously hypertensive rats. The gastrin/D1-like receptor interaction was also confirmed in RPT cells. In RPT cells from Wistar-Kyoto but not spontaneously hypertensive rats, stimulation of either D1-like receptor or gastrin receptor inhibited Na(+)-K(+)-ATPase activity, an effect that was blocked in the presence of SCH23390 or CI-988. In RPT cells from Wistar-Kyoto and spontaneously hypertensive rats, CCKBR and D1 receptor coimmunoprecipitated, which was increased after stimulation of either D1 receptor or CCKBR in RPT cells from Wistar-Kyoto rats; stimulation of one receptor increased the RPT cell membrane expression of the other receptor, effects that were not observed in spontaneously hypertensive rats. These data suggest that there is a synergism between CCKBR and D1-like receptors to increase sodium excretion. An aberrant interaction between the renal CCK BR and D1-like receptors (eg, D1 receptor) may play a role in the pathogenesis of hypertension.

  2. Development of a 3D Tissue Culture-Based High-Content Screening Platform That Uses Phenotypic Profiling to Discriminate Selective Inhibitors of Receptor Tyrosine Kinases.

    PubMed

    Booij, Tijmen H; Klop, Maarten J D; Yan, Kuan; Szántai-Kis, Csaba; Szokol, Balint; Orfi, Laszlo; van de Water, Bob; Keri, Gyorgy; Price, Leo S

    2016-10-01

    3D tissue cultures provide a more physiologically relevant context for the screening of compounds, compared with 2D cell cultures. Cells cultured in 3D hydrogels also show complex phenotypes, increasing the scope for phenotypic profiling. Here we describe a high-content screening platform that uses invasive human prostate cancer cells cultured in 3D in standard 384-well assay plates to study the activity of potential therapeutic small molecules and antibody biologics. Image analysis tools were developed to process 3D image data to measure over 800 phenotypic parameters. Multiparametric analysis was used to evaluate the effect of compounds on tissue morphology. We applied this screening platform to measure the activity and selectivity of inhibitors of the c-Met and epidermal growth factor (EGF) receptor (EGFR) tyrosine kinases in 3D cultured prostate carcinoma cells. c-Met and EGFR activity was quantified based on the phenotypic profiles induced by their respective ligands, hepatocyte growth factor and EGF. The screening method was applied to a novel collection of 80 putative inhibitors of c-Met and EGFR. Compounds were identified that induced phenotypic profiles indicative of selective inhibition of c-Met, EGFR, or bispecific inhibition of both targets. In conclusion, we describe a fully scalable high-content screening platform that uses phenotypic profiling to discriminate selective and nonselective (off-target) inhibitors in a physiologically relevant 3D cell culture setting.

  3. Development of a 3D Tissue Culture–Based High-Content Screening Platform That Uses Phenotypic Profiling to Discriminate Selective Inhibitors of Receptor Tyrosine Kinases

    PubMed Central

    Booij, Tijmen H.; Klop, Maarten J. D.; Yan, Kuan; Szántai-Kis, Csaba; Szokol, Balint; Orfi, Laszlo; van de Water, Bob; Keri, Gyorgy; Price, Leo S.

    2016-01-01

    3D tissue cultures provide a more physiologically relevant context for the screening of compounds, compared with 2D cell cultures. Cells cultured in 3D hydrogels also show complex phenotypes, increasing the scope for phenotypic profiling. Here we describe a high-content screening platform that uses invasive human prostate cancer cells cultured in 3D in standard 384-well assay plates to study the activity of potential therapeutic small molecules and antibody biologics. Image analysis tools were developed to process 3D image data to measure over 800 phenotypic parameters. Multiparametric analysis was used to evaluate the effect of compounds on tissue morphology. We applied this screening platform to measure the activity and selectivity of inhibitors of the c-Met and epidermal growth factor (EGF) receptor (EGFR) tyrosine kinases in 3D cultured prostate carcinoma cells. c-Met and EGFR activity was quantified based on the phenotypic profiles induced by their respective ligands, hepatocyte growth factor and EGF. The screening method was applied to a novel collection of 80 putative inhibitors of c-Met and EGFR. Compounds were identified that induced phenotypic profiles indicative of selective inhibition of c-Met, EGFR, or bispecific inhibition of both targets. In conclusion, we describe a fully scalable high-content screening platform that uses phenotypic profiling to discriminate selective and nonselective (off-target) inhibitors in a physiologically relevant 3D cell culture setting. PMID:27412535

  4. Testosterone-mediated increase in 5 alpha-dihydrotestosterone content, nuclear androgen receptor levels, and cell division in an androgen-independent prostate carcinoma of Noble rats.

    PubMed

    Ho, S M; Leav, I; Damassa, D; Kwan, P W; Merk, F B; Seto, H S

    1988-02-01

    An androgen-independent, transplantable prostate carcinoma line (AIT), originally derived from the dorsolateral prostate (DLP) of Noble rat, was implanted into orchiectomized Noble rats and its response to androgen stimulation was studied and compared to that of the regenerating DLP tissue in sexually ablated rats. AIT tumors carried in castrated hosts displayed a high basal level of proliferative activity (mitotic index (MI), 15.0 +/- 0.5) while DLP tissue in untreated castrates exhibited no proliferative activity. Following androgen stimulation by testosterone capsule implantation into host rats, the AIT responded with a marked increase in cell proliferation; MI values doubled to 30.0 +/- 2.9 on Day 5 following androgen stimulation. This androgen-induced increase in MI values was coincident with elevations in nuclear androgen receptor (20-fold increase) and 5 alpha-dihydrotestosterone content (3-fold increase) in the tumor. However, by Day 10 following androgen treatment, indices of cell proliferation in the AIT declined to pre-androgen-stimulated levels (MI, 14.8 +/- 1.9) despite the continued elevations in nuclear androgen receptor and tissue 5 alpha-dihydrotestosterone contents. Parallel changes in MI were also observed in the normal regenerating DLP following androgen stimulation. MI values in this tissue increased from nondetectable levels to 38.1 +/- 4.7 on Day 5 but declined to relatively low levels (4.5 +/- 0.9) by Day 10 following androgen replacement. Taken together these findings led us to conclude that the AIT carried in castrates is capable of responding to testosterone in a manner similar to that observed for androgen-stimulated DLP of sexually ablated rats. Thus, in both the neoplastic and regenerating tissues, the initial response to androgen is characterized by a marked enhancement of cell proliferation which was correlated with an increase in androgen receptor and 5 alpha-dihydrotestosterone content. However, like its tissue of origin, the AIT

  5. Kinin Receptors Sensitize TRPV4 Channel and Induce Mechanical Hyperalgesia: Relevance to Paclitaxel-Induced Peripheral Neuropathy in Mice.

    PubMed

    Costa, Robson; Bicca, Maíra A; Manjavachi, Marianne N; Segat, Gabriela C; Dias, Fabiana Chaves; Fernandes, Elizabeth S; Calixto, João B

    2017-03-10

    Kinin B1 (B1R) and B2 receptors (B2R) and the transient receptor potential vanilloid 4 (TRPV4) channel are known to play a critical role in the peripheral neuropathy induced by paclitaxel (PTX) in rodents. However, the downstream pathways activated by kinin receptors as well as the sensitizers of the TRPV4 channel involved in this process remain unknown. Herein, we investigated whether kinins sensitize TRPV4 channels in order to maintain PTX-induced peripheral neuropathy in mice. The mechanical hyperalgesia induced by bradykinin (BK, a B2R agonist) or des-Arg(9)-BK (DABK, a B1R agonist) was inhibited by the selective TRPV4 antagonist HC-067047. Additionally, BK was able to sensitize TRPV4, thus contributing to mechanical hyperalgesia. This response was dependent on phospholipase C/protein kinase C (PKC) activation. The selective kinin B1R (des-Arg(9)-[Leu(8)]-bradykinin) and B2R (HOE 140) antagonists reduced the mechanical hyperalgesia induced by PTX, with efficacies and time response profiles similar to those observed for the TRPV4 antagonist (HC-067047). Additionally, both kinin receptor antagonists inhibited the overt nociception induced by hypotonic solution in PTX-injected animals. The same animals presented lower PKCε levels in skin and dorsal root ganglion samples. The selective PKCε inhibitor (εV1-2) reduced the hypotonicity-induced overt nociception in PTX-treated mice with the same magnitude observed for the kinin receptor antagonists. These findings suggest that B1R or B2R agonists sensitize TRPV4 channels to induce mechanical hyperalgesia in mice. This mechanism of interaction may contribute to PTX-induced peripheral neuropathy through the activation of PKCε. We suggest these targets represent new opportunities for the development of effective analgesics to treat chronic pain.

  6. Gamma-hydroxybutyrate (GHB) induces cognitive deficits and affects GABAB receptors and IGF-1 receptors in male rats.

    PubMed

    Johansson, Jenny; Grönbladh, Alfhild; Hallberg, Mathias

    2014-08-01

    In recent years, the abuse of the club drug gamma-hydroxybutyrate (GHB) has become increasingly popular among adolescents. The drug induces euphoria but can also result in sedation, anaesthesia as well as short-term amnesia. In addition, the abuse of GHB causes cognitive impairments and the mechanism by which GHB induces these impairments is not clarified. The present study investigates the impact of GHB treatment on spatial learning and memory using a water maze (WM) test in rats. Furthermore, the behavioural data is combined with an autoradiographic analysis of the GABAB and the IGF-1 receptor systems. The results demonstrate that the animals administered with GHB display an impaired performance in the WM test as compared to controls. In addition, significant alterations in GABAB and IGF-1 receptor density as well as GABAB receptor functionality, were observed in several brain regions associated with cognitive functions e.g. hippocampus. To conclude, our findings suggest that GHB treatment can affect spatial learning and memory, and that this outcome at least to some extent is likely to involve both GABAB and IGF-1 receptors.

  7. Role of Adrenergic Receptors in Glucose, Fructose and Galactose-Induced Increases in Intestinal Glucose Uptake in Dogs.

    PubMed

    Salman, T M; Alada, A R A; Oyebola, D D O

    2014-12-29

    The study investigated the role of adrenergic receptors in glucose, fructose-, and galactose- induced increases in intestinal glucose uptake. Experiments were carried out on fasted male anaesthetized Nigerian local dogs divided into seven groups (with five dogs per group). Group I dogs were administered normal saline and served as control. Dogs in groups II, III and IV were intravenously infused with glucose (1.1 mg/kg/min), fructose (1.1 mg/kg/min) and galactose (1.1 mg/kg/min) respectively. Another three groups, V, VI and VII were pretreated with prazosin (0.2mg/kg), propranolol (0.5mg/kg) or a combination of prazosin (0.2mg/kg) and propranolol (0.5mg/kg) followed by glucose infusion, frutose infusion or galactose infusion respectively. Through a midline laparatomy, the upper jejunum was cannulated for blood flow measurement and blood samples were obtained for measurement of glucose content of the arterial blood and venous blood from the upper jejunal segment. Glucose uptake was calculated as the product of jejunal blood flow and the difference between arterial and venous glucose levels (A-V glucose). The results showed that pretreatment of the animal with prazosin had no effect on glucose and galactose induced increases in glucose uptake. However, pretreatment with propranolol completely abolished glucose, fructose and galactose-induced increases in intestinal glucose uptake. Prazosin also significantly reduced galactose-induced increase in intestinal glucose uptake. The results suggest that the increases in intestinal glucose uptake induced by glucose and fructose are mediated mostly by beta adrenergic receptors while that of galactose is mediated by both alpha and beta adrenergic receptors.

  8. Inosine induces presynaptic inhibition of acetylcholine release by activation of A3 adenosine receptors at the mouse neuromuscular junction

    PubMed Central

    Cinalli, A R; Guarracino, J F; Fernandez, V; Roquel, L I; Losavio, A S

    2013-01-01

    Background and Purpose The role of inosine at the mammalian neuromuscular junction (NMJ) has not been clearly defined. Moreover, inosine was classically considered to be the inactive metabolite of adenosine. Hence, we investigated the effect of inosine on spontaneous and evoked ACh release, the mechanism underlying its modulatory action and the receptor type and signal transduction pathway involved. Experimental Approach End-plate potentials (EPPs) and miniature end-plate potentials (MEPPs) were recorded from the mouse phrenic-nerve diaphragm preparations using conventional intracellular electrophysiological techniques. Key Results Inosine (100 μM) reduced MEPP frequency and the amplitude and quantal content of EPPs; effects inhibited by the selective A3 receptor antagonist MRS-1191. Immunohistochemical assays confirmed the presence of A3 receptors at mammalian NMJ. The voltage-gated calcium channel (VGCC) blocker Cd2+, the removal of extracellular Ca2+ and the L-type and P/Q-type VGCC antagonists, nitrendipine and ω-agatoxin IVA, respectively, all prevented inosine-induced inhibition. In the absence of endogenous adenosine, inosine decreased the hypertonic response. The effects of inosine on ACh release were prevented by the Gi/o protein inhibitor N-ethylmaleimide, PKC antagonist chelerytrine and calmodulin antagonist W-7, but not by PKA antagonists, H-89 and KT-5720, or the inhibitor of CaMKII KN-62. Conclusion and Implications Our results suggest that, at motor nerve terminals, inosine induces presynaptic inhibition of spontaneous and evoked ACh release by activating A3 receptors through a mechanism that involves L-type and P/Q-type VGCCs and the secretory machinery downstream of calcium influx. A3 receptors appear to be coupled to Gi/o protein. PKC and calmodulin may be involved in these effects of inosine. PMID:23731236

  9. Localization of type I interferon receptor limits interferon-induced TLR-3 in epithelial cells

    EPA Science Inventory

    This study aimed to expand on the role of type I IFNs in the influenza-induced upregulation of TLR3 and determine whether and how the localization of the IFN-alpha/beta receptor (IFNAR) in respiratory epithelial cells could modify IFN-induced responses. Using differentiated prima...

  10. Improvement of ketamine-induced social withdrawal in rats: the role of 5-HT7 receptors.

    PubMed

    Hołuj, Małgorzata; Popik, Piotr; Nikiforuk, Agnieszka

    2015-12-01

    Social withdrawal, one of the core negative symptoms of schizophrenia, can be modelled in the social interaction (SI) test in rats using N-methyl-D-aspartate receptor glutamate receptor antagonists. We have recently shown that amisulpride, an antipsychotic with a high affinity for serotonin 5-HT7 receptors, reversed ketamine-induced SI deficits in rats. The aim of the present study was to further elucidate the potential involvement of 5-HT7 receptors in the prosocial action of amisulpride. Acute administration of amisulpride (3 mg/kg) and SB-269970 (1 mg/kg), a 5-HT7 receptor antagonist, reversed ketamine-induced social withdrawal, whereas sulpiride (20 or 30 mg/kg) and haloperidol (0.2 mg/kg) were ineffective. The 5-HT7 receptor agonist AS19 (10 mg/kg) abolished the prosocial efficacy of amisulpride (3 mg/kg). The coadministration of an inactive dose of SB-269970 (0.2 mg/kg) showed the prosocial effects of inactive doses of amisulpride (1 mg/kg) and sulpiride (20 mg/kg). The anxiolytic chlordiazepoxide (2.5 mg/kg) and the antidepressant fluoxetine (2.5 mg/kg) were ineffective in reversing ketamine-induced SI deficits. The present study suggests that the antagonism of 5-HT7 receptors may contribute towards the mechanisms underlying the prosocial action of amisulpride. These results may have therapeutic implications for the treatment of negative symptoms in schizophrenia and other disorders characterized by social withdrawal.

  11. Mastocytosis: a mutated KIT receptor induced myeloproliferative disorder.

    PubMed

    Chatterjee, Anindya; Ghosh, Joydeep; Kapur, Reuben

    2015-07-30

    Although more than 90% systemic mastocytosis (SM) patients express gain of function mutations in the KIT receptor, recent next generation sequencing has revealed the presence of several additional genetic and epigenetic mutations in a subset of these patients, which confer poor prognosis and inferior overall survival. A clear understanding of how genetic and epigenetic mutations cooperate in regulating the tremendous heterogeneity observed in these patients will be essential for designing effective treatment strategies for this complex disease. In this review, we describe the clinical heterogeneity observed in patients with mastocytosis, the nature of relatively novel mutations identified in these patients, therapeutic strategies to target molecules downstream from activating KIT receptor and finally we speculate on potential novel strategies to interfere with the function of not only the oncogenic KIT receptor but also epigenetic mutations seen in these patients.

  12. [Autoimmune encephalitis induced by antibodies against GABA-A receptor].

    PubMed

    González R, Pablo; Hudson A, Lorena; Basáez M, Esteban; Miranda C, Marcelo

    2016-11-01

    Among autoimmune encephalitides, a prevalent group are those associated with antibodies against the N-Methyl-D-aspartate receptor, which present with behavior abnormalities, psychosis, seizures and abnormal movements. A new variant, mediated by antibodies against the GABA-A receptor, was recen-tly described. We report a 66-years-old female with this form of encephalitis whose main manifestation was the presence of severe seizures leading to status epilepticus. The patient had a good response to immunomodulatory therapy with intravenous methylprednisolone, azathioprine and anticonvulsants. The laboratory tests initially detected anti-thyroid peroxidase antibodies which lead to the misdiagnosis of Hashimoto Encephalitis, which was ruled out after the detection of antibodies against GABA-A receptor. No malignancy was detected.

  13. Mastocytosis: a mutated KIT receptor induced myeloproliferative disorder

    PubMed Central

    Chatterjee, Anindya; Ghosh, Joydeep; Kapur, Reuben

    2015-01-01

    Although more than 90% systemic mastocytosis (SM) patients express gain of function mutations in the KIT receptor, recent next generation sequencing has revealed the presence of several additional genetic and epigenetic mutations in a subset of these patients, which confer poor prognosis and inferior overall survival. A clear understanding of how genetic and epigenetic mutations cooperate in regulating the tremendous heterogeneity observed in these patients will be essential for designing effective treatment strategies for this complex disease. In this review, we describe the clinical heterogeneity observed in patients with mastocytosis, the nature of relatively novel mutations identified in these patients, therapeutic strategies to target molecules downstream from activating KIT receptor and finally we speculate on potential novel strategies to interfere with the function of not only the oncogenic KIT receptor but also epigenetic mutations seen in these patients. PMID:26158763

  14. Regulatory role of the cannabinoid CB2 receptor in stress-induced neuroinflammation in mice

    PubMed Central

    Zoppi, S; Madrigal, J L; Caso, J R; García-Gutiérrez, M S; Manzanares, J; Leza, J C; García-Bueno, B

    2014-01-01

    Background and Purpose Stress exposure produces excitotoxicity and neuroinflammation, contributing to the cellular damage observed in stress-related neuropathologies. The endocannabinoids provide a homeostatic system, present in stress-responsive neural circuits. Here, we have assessed the possible regulatory role of cannabinoid CB2 receptors in stress-induced excitotoxicity and neuroinflammation. Experimental Approach We used wild type (WT), transgenic overexpressing CB2 receptors (CB2xP) and CB2 receptor knockout (CB2-KO) mice exposed to immobilization and acoustic stress (2 h·day−1 for 4 days). The CB2 receptor agonist JWH-133 was administered daily (2 mg·kg−1, i.p.) to WT and CB2-KO animals. Glutamate uptake was measured in synaptosomes from frontal cortex; Western blots and RT-PCR were used to measure proinflammatory cytokines, enzymes and mediators in homogenates of frontal cortex. Key Results Increased plasma corticosterone induced by stress was not modified by manipulating CB2 receptors. JWH-133 treatment or overexpression of CB2 receptors increased control levels of glutamate uptake, which were reduced by stress back to control levels. JWH-133 prevented the stress-induced increase in proinflammatory cytokines (TNF-α and CCL2), in NF-κB, and in NOS-2 and COX-2 and in the consequent cellular oxidative and nitrosative damage (lipid peroxidation). CB2xP mice exhibited anti-inflammatory or neuroprotective actions similar to those in JWH-133 pretreated animals. Conversely, lack of CB2 receptors (CB2-KO mice) exacerbated stress-induced neuroinflammatory responses and confirmed that effects of JWH-133 were mediated through CB2 receptors. Conclusions and Implications Pharmacological manipulation of CB2 receptors is a potential therapeutic strategy for the treatment of stress-related pathologies with a neuroinflammatory component, such as depression. PMID:24467609

  15. Intracellular NAADP increase induced by extracellular NAADP via the P2Y11-like receptor.

    PubMed

    Djerada, Zoubir; Millart, Hervé

    2013-06-28

    The aim of the study was to identify a signalling pathway allowing NAADP-induced intracellular NAADP increase and involving the P2Y11-like receptor. P2Y11-like and β-adrenergic receptors may play important regulatory roles within the cardiovascular system. Both receptors have been shown to be involved in triggering myocardial preconditioning. Using a Langendorff model we report a positive inotropic response induced by extracellular NAADP via P2Y11-like receptor stimulation. In cardiomyocyte cultures, P2Y11-like receptor stimulation by extracellular NAADP ([NAADP]e) increased intracellular cADP-ribose and NAADP concentration as evidenced by direct measurements. NF546, a new selective P2Y11 receptor agonist, increased intracellular cAMP, cADP-ribose and NAADP concentration confirming the involvement of the P2Y11-like receptor in this signalling pathway. NF157, a P2Y11 receptor antagonist, suppressed the increase in intracellular cADPr, NAADP and NAAD induced by either [NAADP]e or NF546. The response profile for intracellular cADP-ribose and NAADP concentration following P2Y11-like stimulation with NF546 was similar to reported data relating β-adrenergic stimulation with isoprenaline. This response represents the signature of the Gs/ADP-ribosyl cyclase activity. Moreover, this study provides a signalling pathway: intracellular NAADP increase induced by extracellular NAADP via metabotropic activity of P2Y11-like receptor. This pathway implying P2Y11-like could take part in the intracellular calcium rise reported for extracellular NAADP.

  16. Cholinergic and GABAergic receptor functional deficit in the hippocampus of insulin-induced hypoglycemic and streptozotocin-induced diabetic rats.

    PubMed

    Sherin, A; Anu, J; Peeyush, K T; Smijin, S; Anitha, M; Roshni, B T; Paulose, C S

    2012-01-27

    Neurotransmitter receptor functional regulation plays an important role in controlling the excitability and responsiveness of hippocampal neurons. Deregulation of its function is associated with seizure generation, motor deficits, and memory impairment. In the present study we investigated the changes in hippocampal cholinergic and GABA receptor binding and gene expression in insulin-induced hypoglycemic and streptozotocin-induced diabetic rats. Expression of cholinergic enzymes; acetylcholine esterase (AChE) and choline acetyltransferase (ChAT) upregulated and downregulated, respectively, in diabetic group, which was further exacerbated by hypoglycemia. Total muscarinic receptor, muscarinic M1, and GABA maximal binding (B(max)) significantly decreased in hypoglycemic and diabetic rats. In hypoglycemic group, the B(max) showed further decline compared with diabetes. Muscarinic M3 receptor B(max) and gene expression upregulated in hypoglycemic and diabetic group. Alpha7 nicotinic acetylcholine receptor (α7 nAChR) expression significantly downregulated in hypoglycemic and diabetic rats. Gene expression of glutamate decarboxylase (GAD), GABAAα1, and GABAB in hypoglycemic and diabetic rats downregulated, with more significant decrease in hypoglycemic group. Present findings show altered cholinergic, muscarinic, nicotinic receptor expression and thereby function. Decreased GABA receptor expression is associated with decline in GABAergic neurotransmission. Thus cholinergic receptor dysfunction and decreased GABAergic neuroprotective inhibitory function in the hippocampus of hypoglycemic and diabetic rats account for the increased vulnerability of hippocampus predisposing to neuronal damage, which is suggested to contribute to cognitive impairment and memory deficit reported in hypoglycemia and diabetes. Also, recurrent hypoglycemia in diabetes exacerbates the hippocampal dysfunction induced by diabetes, which has clinical significance in diabetes therapy.

  17. Farnesol induces thyroid hormone receptor (THR) {beta}1 but inhibits THR-mediated signaling in MCF-7 human breast cancer cells

    SciTech Connect

    Duncan, Robin E.; Archer, Michael C. . E-mail: m.archer@utoronto.ca

    2006-04-28

    Anti-cancer effects of farnesol are well established, although mechanisms mediating these effects are not fully understood. Since farnesol has been shown to regulate gene transcription through activation of the farnesoid X receptor and the peroxisome proliferator-activated receptors-{alpha} and -{gamma}, we hypothesized that farnesol may also mediate some of its effects through other nuclear hormone receptors. Here we showed that in MCF-7 human breast cancer cells, farnesol induced the expression of thyroid hormone receptor (THR) {beta}1 mRNA and protein at concentrations that inhibited cell growth. Changes in the expression of THR responsive genes, however, suggested that farnesol inhibits THR-mediated signaling. Protein extracts from cells treated with farnesol displayed decreased binding to oligodeoxynucleotides containing a consensus sequence for the THR response element, despite the higher THR{beta}1 content, providing a mechanism to explain the decreased transcriptional activity of cellular THRs.

  18. Cyclosporine A-induced increase in glomerular cyclic GMP in rats and the involvement of the endothelinB receptor

    PubMed Central

    Tack, Ivan; Marin-Castano, Encarna; Bascands, Jean-Loup; Pecher, Christiane; Ader, Jean-Louis; Girolami, Jean-Pierre

    1997-01-01

    A transient two fold increase in the cyclic GMP content was observed in rat freshly isolated glomeruli 6 to 9 h after a single subcutaneous injection of 20 mg kg−1 cyclosporine A (CsA) in conscious animals. In vitro stimulation with endothelin 3 (ET-3) of isolated glomeruli obtained from CsA-untreated rats resulted in a dose-dependent increase in cyclic GMP content. The increase observed with 10 nM ET-3 was similar to that observed in glomeruli isolated 9 h after in vivo CsA administration. The rise in glomerular cyclic GMP content after in vivo CsA injection was prevented by in vivo treatment with L-NAME (10 mg kg−1) or by in vitro calcium deprivation of the incubation medium. The stimulating effects of CsA on glomerular cyclic GMP content were inhibited by in vivo administration of the ETB receptor antagonist BQ-788 (2 mg kg−1) but not by the ETA receptor antagonist BQ-123 (2 mg kg−1). The maximum increase in glomerular cyclic GMP content induced in vitro by acetylcholine (100 μM) and by ET-3 (100 nM) was slightly lower (approximately by 20–25%, P<0.05) in glomeruli from CsA-treated rats than in glomeruli from untreated rats. In contrast, the maximum increase achieved with 1 μM sodium nitroprusside was similar in both groups. A single subcutaneous injection of CsA did not significantly alter the glomerular mRNA expression of constitutive endothelial NO synthase (eNOS), as evaluated by RT–PCR, whereas the mRNA expression of the inducible NO synthase (iNOS), which follows pretreatment with lipopolysaccharide, was prevented. These results indicate that in vivo administration of a single dose of cyclosporine A transiently increases the cyclic GMP content of freshly isolated glomeruli, and that activation of ETB receptors and stimulation of the NO pathway are involved in this process. Furthermore, a single administration of CsA does not impair eNOS mRNA expression and only slightly reduces NO-dependent glomerular cyclic GMP

  19. Effects of sigma(1) receptor ligand MS-377 on D(2) antagonists-induced behaviors.

    PubMed

    Karasawa, Jun-ichi; Takahashi, Shinji; Takagi, Kaori; Horikomi, Kazutoshi

    2002-10-01

    (R)-(+)-1-(4-Chlorophenyl)-3-[4-(2-methoxyethyl)piperazin-1-yl]methyl-2-pyrrolidinone L-tartrate (MS-377) is a novel antipsychotic agent with selective and high affinity for sigma(1) receptor. The present study was carried out to clarify the interaction of MS-377 with dopamine D(2) receptor antagonists (D(2) antagonists) in concurrent administration, and then the involvement of sigma receptors in the interaction. The effects of MS-377 on haloperidol- or sultopride-induced inhibition of apomorphine-induced climbing behavior and catalepsy were investigated in mice and rats, respectively. In addition, the effects of (+)-SKF-10,047 and SA4503, both of which are sigma receptor agonists, and WAY-100,635, which is a 5-HT(1A) receptor antagonist, on the interaction due to the concurrent use were also investigated. MS-377 potentiated the inhibitory effects of haloperidol or sultopride on apomorphine-induced climbing behavior in a dose-dependent manner. In contrast, MS-377 did not affect the catalepsy induction by these drugs. The potentiation of the inhibitory effects of haloperidol or sultopride on apomorphine-induced climbing behavior by MS-377 was not inhibited by WAY-100,635, but was inhibited by (+)-SKF-10,047 and SA4503. These findings showed that MS-377 potentiates the efficacy of D(2) antagonists, but it does not deteriorate the adverse effect. Moreover, sigma(1) receptors are involved in this potentiation of the efficacy of D(2) antagonists by MS-377.

  20. Castor oil induces laxation and uterus contraction via ricinoleic acid activating prostaglandin EP3 receptors.

    PubMed

    Tunaru, Sorin; Althoff, Till F; Nüsing, Rolf M; Diener, Martin; Offermanns, Stefan

    2012-06-05

    Castor oil is one of the oldest drugs. When given orally, it has a laxative effect and induces labor in pregnant females. The effects of castor oil are mediated by ricinoleic acid, a hydroxylated fatty acid released from castor oil by intestinal lipases. Despite the wide-spread use of castor oil in conventional and folk medicine, the molecular mechanism by which ricinoleic acid acts remains unknown. Here we show that the EP(3) prostanoid receptor is specifically activated by ricinoleic acid and that it mediates the pharmacological effects of castor oil. In mice lacking EP(3) receptors, the laxative effect and the uterus contraction induced via ricinoleic acid are absent. Although a conditional deletion of the EP(3) receptor gene in intestinal epithelial cells did not affect castor oil-induced diarrhea, mice lacking EP(3) receptors only in smooth-muscle cells were unresponsive to this drug. Thus, the castor oil metabolite ricinoleic acid activates intestinal and uterine smooth-muscle cells via EP(3) prostanoid receptors. These findings identify the cellular and molecular mechanism underlying the pharmacological effects of castor oil and indicate a role of the EP(3) receptor as a target to induce laxative effects.

  1. Toll Like Receptor 4 Affects the Cerebral Biochemical Changes Induced by MPTP Treatment.

    PubMed

    Conte, Carmela; Roscini, Luca; Sardella, Roccaldo; Mariucci, Giuseppina; Scorzoni, Stefania; Beccari, Tommaso; Corte, Laura

    2017-02-01

    The etiology and pathogenesis of Parkinson's disease (PD) are still unclear. However, multiple lines of evidence suggest a critical role of the toll like receptor 4 (TLR4) in inflammatory response and neuronal death. Neuroinflammation may be associated with the misfolding and aggregation of proteins accompanied by a change in their secondary structure. Recent findings also suggest that biochemical perturbations in cerebral lipid content could contribute to the pathogenesis of central nervous system (CNS) disorders, including PD. Thus, it is of great importance to determine the biochemical changes that occur in PD. In this respect, Fourier Transform Infrared (FTIR) spectroscopy represents a useful tool to detect molecular alterations in biological systems in response to stress stimuli. By relying upon FTIR approach, this study was designed to elucidate the potential role of TLR4 in biochemical changes induced by methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin in a mouse model of PD. The analysis of the FTIR spectra was performed in different brain regions of both wild type (WT) and toll like receptor 4-deficient (TLR4(-/-)) mice. It revealed that each brain region exhibited a characteristic molecular fingerprint at baseline, with no significant differences between genotypes. Conversely, WT and TLR4(-/-) mice showed differential biochemical response to MPTP toxicity, principally related to lipid and protein composition. These differences appeared to be characteristic for each brain area. Furthermore, the present study showed that WT mice resulted more vulnerable than TLR4(-/-) animals to striatal dopamine (DA) depletion following MPTP treatment. These results support the hypothesis of a possible involvement of TLR4 in biochemical changes occurring in neurodegeneration.

  2. Effect of sodium hydrosulfide on mRNA expression of prostaglandin E2 receptors in response to mucosal acidification and distention-induced gastric acid secretion in rats

    PubMed Central

    Mard, Seyyed Ali; Mahini, Simin; Dianat, Mahin; Farbood, Yaghoob

    2017-01-01

    Objective(s): Prostaglandins have been shown to mediate the gastro-protective effect of sodium hydrosulfide (NaHS) but effect of NaHS on mRNA expression of prostaglandin E2 receptors (EP1, 3-4; EPs) has not been investigated. Therefore, this study designed to evaluate the effect of NaHS on mRNA expression of EPs receptors in response to mucosal acidification and distention-induced gastric acid secretion in rats. Materials and Methods: Fasted rats were randomly assigned into 4 groups (n=6/group). They were control, and NaHS-treated groups. To evaluate the effect of NaHS on mucosal mRNA expression of EPs receptors, the gastric mucosa exposed to stimulated gastric acid output and mucosal acidification. The pylorus sphincter catheterized for instillation of isotonic neutral saline or acidic solution. Ninety min after beginning the experiments, animals sacrificed and the gastric mucosa collected to determine the pH, mucus secretion and to quantify the mRNA expression of EPs receptors by quantitative real-time PCR. Results: present results showed that a) NaHS increased the mucus secretion, mRNA expression of EP3 and EP4 receptors in response to distention-induced expression; b) The mRNA expression of EP1 receptors increased while EP4 mRNA receptors decreased in response to mucosal acidification in NaHS-pretreated rats; and c) NaHS increased pH of gastric contents both in response to distention-induced gastric acid secretion and mucosal acidification. Conclusion: NaHS behaves in a different manner. It effectively only increased the pH of gastric contents to reinforce the gastric mucosa against a highly acidic solution but modulated both acid and mucus secretion when the rate of acid increase in the stomach was slower. PMID:28293390

  3. Histamine receptor type coupled to nitric oxide-induced relaxation of guinea-pig nasal mucosa.

    PubMed

    Bockman, C S; Zeng, W

    2002-01-01

    1 The aim of this study was to characterize the histamine receptor type mediating relaxation of the vascular bed of the nasal mucosa from the guinea-pig, and to determine the role of cyclo-oxygenase products and nitric oxide in this relaxant response to histamine. These studies were performed in isolated nasal mucosae examined in vitro to obtain potencies of histamine receptor-type selective agonists in causing vasorelaxation and to determine affinities of histamine receptor antagonists for inhibiting histamine-induced relaxation. 2 After contraction of nasal mucosae with noradrenaline, histamine caused a maximal relaxation response that was 75 +/- 6% of the contraction caused by noradrenaline with a mean EC50 value of 4.3 +/- 0.5 microM. Neither dimaprit (H2-receptor selective) nor R-alpha-methylhistamine (H3-receptor selective) caused significant relaxation of nasal mucosae. In contrast, betahistine (H1-receptor selective) caused an 81 +/- 7% relaxation of noradrenaline-induced tone with an EC50 value of 15 +/- 1 microM. 3 pA2 experiments were performed to obtain KB values of chlorpheniramine (H1-receptor selective) and diphenhydramine (H1-receptor selective) for blocking histamine-stimulated relaxation of nasal mucosae. KB values for chlorpheniramine (0.87 nM) and diphenhydramine (7.4 nM) were consistent with their interaction at the H1-receptor type. Additionally, neither 10 microM cimetidine (H2-receptor selective) nor 1 microM thioperamide (H3-receptor selective) had any effect on the relaxation curve for histamine. 4 In the presence of 10 microM indomethacin (cyclo-oxygenase inhibitor), histamine caused a maximal relaxation response of 73 +/- 5% of the noradrenaline-induced tone with an EC50 value of 2.9 +/- 0.2 microM, which was not different from control values (EC50 = 5.0 +/- 0.4 microM; maximal relaxation = 71 +/- 6%). In contrast, 200 microM NG-nitro-L-arginine (nitric oxide synthase inhibitor) completely inhibited histamine-induced relaxation of nasal

  4. The 5-HT3 receptor is essential for exercise-induced hippocampal neurogenesis and antidepressant effects.

    PubMed

    Kondo, M; Nakamura, Y; Ishida, Y; Shimada, S

    2015-11-01

    Exercise has a variety of beneficial effects on brain structure and function, such as hippocampal neurogenesis, mood and memory. Previous studies have shown that exercise enhances hippocampal neurogenesis, induces antidepressant effects and improves learning behavior. Brain serotonin (5-hydroxytryptamine, 5-HT) levels increase following exercise, and the 5-HT system has been suggested to have an important role in these exercise-induced neuronal effects. However, the precise mechanism remains unclear. In this study, analysis of the 5-HT type 3A receptor subunit-deficient (htr3a(-/-)) mice revealed that lack of the 5-HT type 3 (5-HT3) receptor resulted in loss of exercise-induced hippocampal neurogenesis and antidepressant effects, but not of learning enhancement. Furthermore, stimulation of the 5-HT3 receptor promoted neurogenesis. These findings demonstrate that the 5-HT3 receptor is the critical target of 5-HT action in the brain following exercise, and is indispensable for hippocampal neurogenesis and antidepressant effects induced by exercise. This is the first report of a pivotal 5-HT receptor subtype that has a fundamental role in exercise-induced morphological changes and psychological effects.

  5. The platelet fibrinogen receptor: an immunogold-surface replica study of agonist-induced ligand binding and receptor clustering

    PubMed Central

    1987-01-01

    Platelet aggregation requires the binding of fibrinogen to its receptor, a heterodimer consisting of the plasma-membrane glycoproteins (GP) IIb and IIIa. Although the GPIIb-IIIa complex is present on the surface of unstimulated platelets, it binds fibrinogen only after platelet activation. We have used an immunogold-surface replica technique to study the distribution of GPIIb-IIIa and bound fibrinogen over broad areas of surface membranes in unstimulated, as well as thrombin-activated and ADP-activated human platelets. We found that the immunogold-labeled GPIIb-IIIa was monodispersed over the surface of unstimulated platelets, although the cell surface lacked immunoreactive fibrinogen. On thrombin-stimulated platelets, approximately 65% of the GPIIb-IIIa molecules were in clusters within the plane of the membrane. Fibrinogen, which had been released from the alpha-granules of these cells, bound to GPIIb-IIIa on the cell surface and was similarly clustered. To determine whether the receptors clustered before ligand binding, or as a consequence thereof, we studied the surface distribution of GPIIb-IIIa after stimulation with ADP, which causes activation of the fibrinogen receptor function of GPIIb-IIIa without inducing the release of fibrinogen. In the absence of added fibrinogen, the unoccupied, yet binding-competent receptors on ADP-stimulated platelets were monodispersed. The addition of fibrinogen caused the GPIIb-IIIa molecules to cluster on the cell surface. Clustering was also induced by the addition of the GPIIb-IIIa-binding domains of fibrinogen, namely the tetrapeptide Arg-Gly-Asp-Ser on the alpha-chain or the gamma-chain decapeptide gamma 402-411. These results show that receptor occupancy causes clustering of GPIIb-IIIa in activated platelets. PMID:3584243

  6. GHB-Induced Cognitive Deficits During Adolescence and the Role of NMDA Receptor.

    PubMed

    Sircar, R; Wu, L-C; Reddy, K; Sircar, D; Basak, A K

    2011-03-01

    We have earlier reported that γ-hydroxybutyric acid (GHB) disrupts the acquisition of spatial learning and memory in adolescent rats. GHB is known to interact with several neurotransmitter systems that have been implicated in cognitive functioning. The N-methyl-D-aspartate receptor (NR) -type of glutamate receptor is considered to be an important target for spatial learning and memory. Molecular mechanisms governing the neuroadptations following repeated GHB treatment in adolecent rats remain unknown. We examined the role of NMDA receptor in adolescent GHB-induced cognitive deficit. Adolescent rats were administered with GHB on 6 consecutive days, and surface-expressed NMDA receptor subunits levels were measured. GHB significantly decreased NR1 levels in the frontal cortex. Adolescent GHB also significantly reduced cortical NR2A subunit levels. Our findings support the hypothesis that adolescent GHB-induced cogntive deficits are associated with neuroadaptations in glutamatergic transmission, particulaly NR functioning in the frontal cortex.

  7. GHB–Induced Cognitive Deficits During Adolescence and the Role of NMDA Receptor

    PubMed Central

    Sircar, R; Wu, L-C; Reddy, K; Sircar, D; Basak, A.K

    2011-01-01

    We have earlier reported that γ-hydroxybutyric acid (GHB) disrupts the acquisition of spatial learning and memory in adolescent rats. GHB is known to interact with several neurotransmitter systems that have been implicated in cognitive functioning. The N-methyl-D-aspartate receptor (NR) -type of glutamate receptor is considered to be an important target for spatial learning and memory. Molecular mechanisms governing the neuroadptations following repeated GHB treatment in adolecent rats remain unknown. We examined the role of NMDA receptor in adolescent GHB-induced cognitive deficit. Adolescent rats were administered with GHB on 6 consecutive days, and surface-expressed NMDA receptor subunits levels were measured. GHB significantly decreased NR1 levels in the frontal cortex. Adolescent GHB also significantly reduced cortical NR2A subunit levels. Our findings support the hypothesis that adolescent GHB-induced cogntive deficits are associated with neuroadaptations in glutamatergic transmission, particulaly NR functioning in the frontal cortex. PMID:21886597

  8. Tranexamic acid induces kaolin intake stimulating a pathway involving tachykinin neurokinin 1 receptors in rats.

    PubMed

    Kakiuchi, Hitoshi; Kawarai-Shimamura, Asako; Kuwagata, Makiko; Orito, Kensuke

    2014-01-15

    Tranexamic acid suppresses post-partum haemorrhage and idiopathic menorrhagia through its anti-fibrinolytic action. Although it is clinically useful, it is associated with high risks of side effects such as emesis. Understanding the mechanisms underlying tranexamic acid-induced emesis is very important to explore appropriate anti-emetic drugs for the prevention and/or suppression of emesis. In this study, we examined the receptors involved in tranexamic acid-induced kaolin intake in rats, which reflects the drug's clinical emetogenic potential in humans. Further, we examined the brain regions activated by administration of tranexamic acid and elucidated pivotal pathways of tranexamic acid-induced kaolin intake. We examined the effects of ondansetron, a 5-hydroxytryptamine 3 receptor antagonist, domperidone, a dopamine 2 receptor antagonist, and aprepitant, a tachykinin neurokinin 1 (NK1) receptor antagonist, on tranexamic acid-induced kaolin intake in rats. Then, we determined the brain regions that showed increased numbers of c-Fos immunoreactive cells. Finally, we examined the effects of an antagonist(s) that reduced tranexamic acid-induced kaolin intake on the increase in c-Fos immunoreactive cells. Aprepitant significantly decreased tranexamic acid-induced kaolin intake. However, neither ondansetron nor domperidone decreased kaolin intake. Tranexamic acid significantly increased c-Fos immunoreactive cells by approximately 5.5-fold and 22-fold in the area postrema and nucleus of solitary tract, respectively. Aprepitant decreased the number of c-Fos immunoreactive cells in both areas. Tranexamic acid induced kaolin intake possibly via stimulation of tachykinin NK1 receptors in rats. The tachykinin NK1 receptor could be targeted to prevent and/or suppress emesis in patients receiving tranexamic acid.

  9. A(1) and A(3) adenosine receptors inhibit LPS-induced hypoxia-inducible factor-1 accumulation in murine astrocytes.

    PubMed

    Gessi, Stefania; Merighi, Stefania; Stefanelli, Angela; Fazzi, Debora; Varani, Katia; Borea, Pier Andrea

    2013-10-01

    Adenosine (Ado) exerts neuroprotective and anti-inflammatory functions by acting through four receptor subtypes A1, A2A, A2B and A3. Astrocytes are one of its targets in the central nervous system. Hypoxia-inducible factor-1 (HIF-1), a master regulator of oxygen homeostasis, is induced after hypoxia, ischemia and inflammation and plays an important role in brain injury. HIF-1 is expressed by astrocytes, however the regulatory role played by Ado on HIF-1α modulation induced by inflammatory and hypoxic conditions has not been investigated. Primary murine astrocytes were activated with lipopolysaccharide (LPS) with or without Ado, Ado receptor agonists, antagonists and receptor silencing, before exposure to normoxia or hypoxia. HIF-1α accumulation and downstream genes regulation were determined. Ado inhibited LPS-increased HIF-1α accumulation under both normoxic and hypoxic conditions, through activation of A1 and A3 receptors. In cells incubated with the blockers of p44/42 MAPK and Akt, LPS-induced HIF-1α accumulation was significantly decreased in normoxia and hypoxia, suggesting the involvement of p44/42 MAPK and Akt in this effect and Ado inhibited kinases phosphorylation. A series of angiogenesis and metabolism related genes were modulated by hypoxia in an HIF-1 dependent way, but not further increased by LPS, with the exception of GLUT-1 and hexochinase II that were elevated by LPS only in normoxia and inhibited by Ado receptors. Instead, genes involved in inflammation, like inducible nitric-oxide synthase (iNOS) and A2B receptors, were increased by LPS in normoxia, strongly stimulated by LPS in concert with hypoxia and inhibited by Ado, through A1 and A3 receptor subtypes. In conclusion A1 and A3 receptors reduce the LPS-mediated HIF-1α accumulation in murine astrocytes, resulting in a downregulation of genes involved in inflammation and hypoxic injury, like iNOS and A2B receptors, in both normoxic and hypoxic conditions.

  10. Nociceptin/orphanin FQ receptor agonists attenuate L-DOPA-induced dyskinesias.

    PubMed

    Marti, Matteo; Rodi, Donata; Li, Qin; Guerrini, Remo; Fasano, Stefania; Morella, Ilaria; Tozzi, Alessandro; Brambilla, Riccardo; Calabresi, Paolo; Simonato, Michele; Bezard, Erwan; Morari, Michele

    2012-11-14

    In the present study we investigated whether the neuropeptide nociceptin/orphanin FQ (N/OFQ), previously implicated in the pathogenesis of Parkinson's disease, also affects L-DOPA-induced dyskinesia. In striatal slices of naive rodents, N/OFQ (0.1-1 μm) prevented the increase of ERK phosphorylation and the loss of depotentiation of synaptic plasticity induced by the D1 receptor agonist SKF38393 in spiny neurons. In vivo, exogenous N/OFQ (0.03-1 nmol, i.c.v.) or a synthetic N/OFQ receptor agonist given systemically (0.01-1 mg/Kg) attenuated dyskinesias expression in 6-hydroxydopamine hemilesioned rats primed with L-DOPA, without causing primary hypolocomotive effects. Conversely, N/OFQ receptor antagonists worsened dyskinesia expression. In vivo microdialysis revealed that N/OFQ prevented dyskinesias simultaneously with its neurochemical correlates such as the surge of nigral GABA and glutamate, and the reduction of thalamic GABA. Regional microinjections revealed that N/OFQ attenuated dyskinesias more potently and effectively when microinjected in striatum than substantia nigra (SN) reticulata, whereas N/OFQ receptor antagonists were ineffective in striatum but worsened dyskinesias when given in SN. Quantitative autoradiography showed an increase in N/OFQ receptor binding in striatum and a reduction in SN of both unprimed and dyskinetic 6-hydroxydopamine rats, consistent with opposite adaptive changes of N/OFQ transmission. Finally, the N/OFQ receptor synthetic agonist also reduced dyskinesia expression in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated dyskinetic macaques without affecting the global parkinsonian score. We conclude that N/OFQ receptor agonists may represent a novel strategy to counteract L-DOPA-induced dyskinesias. Their action is possibly mediated by upregulated striatal N/OFQ receptors opposing the D1 receptor-mediated overactivation of the striatonigral direct pathway.

  11. Autoregulation of bradykinin receptors and bradykinin-induced prostacyclin formation in human fibroblasts.

    PubMed Central

    Roscher, A A; Manganiello, V C; Jelsema, C L; Moss, J

    1984-01-01

    The interaction of bradykinin (BK) with its specific receptors on intact cultured human fibroblasts results in production of prostaglandins, including prostacyclin (PGI2), and accumulation of cyclic AMP. Incubation of cells with 1 microM BK for 5 min at 37 degrees C led to a marked reduction (75-90%) in BK-induced PGI2 release and in total number of [3H]BK-binding sites with no change in dissociation constant (6.1 and 7.6 nM for control and BK-treated cells, respectively). The decrease in receptor number did not result from BK transferred from the first incubation into the binding assay. BK-induced receptor loss was temperature dependent; exposure of cells to BK at 4 degrees C had little or no effect on receptor number. After incubation with BK for approximately equal to 15 min, further incubation in the absence of BK for 30 min at 37 degrees C almost completely restored both receptor number and BK-induced PGI2 release. With more prolonged exposure to BK (greater than 1 h), restoration of receptors was inversely related to the length of exposure and the concentration of BK. Recovery was unaffected by cycloheximide. During prolonged incubation without removal of BK, cells began to recover receptors by 5 h; greater than 99% of the bradykinin initially present disappeared by 3 h. Bacitracin greatly retarded BK disappearance and totally prevented recovery. These observations provide direct evidence that the number of BK receptors on cultured human fibroblasts can be regulated by BK itself. In addition, it appears that BK-degrading systems, by influencing local concentrations of the peptide, may play an important role in the autoregulation of BK receptors. The presence of highly active degradation systems might serve to protect target tissues from developing chronic insensitivity to BK and, perhaps, similar peptides. PMID:6146639

  12. Tributyltin exposure influences predatory behavior, neurotransmitter content and receptor expression in Sebastiscus marmoratus.

    PubMed

    Yu, Ang; Wang, Xinli; Zuo, Zhenghong; Cai, Jiali; Wang, Chonggang

    2013-03-15

    Tributyltin (TBT) is a ubiquitous marine contaminant due to its extensive use as a biocide, fungicide and antifouling agent. However, the neurotoxic effect of TBT has not been extensively studied, especially in marine fish. This study was conducted to investigate the effects of TBT (10, 100 and 1000 ng/L) on the predatory behavior of Sebastiscus marmoratus and to look into the mechanism involved. The results showed that TBT exposure depressed predatory activity after 50 days exposure. Dopamine levels in the fish brains increased in a dose-dependent manner, while 5-hydroxytryptamine and norepinephrine levels decreased significantly in the TBT exposure group compared to the control. The mRNA levels of dopamine receptors, which have functions such as cognition, motor activity, motivation and reward, mood, attention and learning, were significantly down-regulated by TBT exposure. Although the levels of amino acid neurotransmitters, including glutamate, did not show marked alteration, the expression of the glutamatergic signaling pathway such as N-methyl-D-aspartate receptors, a-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor, calmodulin, Ca(2+)/calmodulin-dependent protein kinases-II and cyclic adenosine monophosphate responsive element binding protein, was significantly reduced by TBT exposure, which indicated that central nerve activities were in a state of depression, thus affecting the predatory activities of the fish.

  13. Inhibitory effect of vasopressin receptor antagonist OPC-31260 on experimental brain oedema induced by global cerebral ischaemia.

    PubMed

    Molnár, A H; Varga, C; Berkó, A; Rojik, I; Párducz, A; László, F; László, F A

    2008-03-01

    The effects of the non-peptide vasopressin V(2) receptor antagonist 5-dimethylamino-1-[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC-31260) on the cerebral oedema induced by general cerebral hypoxia were studied in rats. The general cerebral hypoxia was produced by bilateral common carotid ligation in Sprague-Dawley rats of the CFY strain. By 6 h after the ligation, half of the rats had died, but the survival rate was significantly higher following OPC-31260 administration. Electron microscopic examinations revealed typical ischaemic changes after the carotid ligation. The carotid ligation increased the brain contents of water and Na(+) and enhanced the plasma vasopressin level. The increased brain water and Na(+) accumulation was prevented by OPC-31260 administration, but the plasma vasopressin level was further enhanced by OPC-31260. These results demonstrate the important role of vasopressin in the development of the disturbances in brain water and electrolyte balance in response to general cerebral hypoxia. The carotid ligation-induced cerebral oedema was significantly reduced following oral OPC-31260 administration. The protective mechanism exerted by OPC-31260 stems from its influence on the renal vasopressin V(2) receptors. These observations might suggest an effective approach to the treatment of global hypoxia-induced cerebral oedema in humans.

  14. Trace metal content in aspirin and women's cosmetics via proton induced x-ray emission (PIXE)

    SciTech Connect

    Hichwa, B.P.; Pun, D.D.; Wang, D.

    1981-04-01

    A multielemental analysis to determine the trace metal content of generic and name-brand aspirins and name-brand lipsticks was done via proton induced x-ray (PIXE) measurements. The Hope College PIXE system is described as well as the target preparation methods. The trace metal content of twelve brands of aspirin and aspirin substitutes and fourteen brands of lipstick are reported. Detection limits for most elements are in the range of 100 parts per billion (ppb) to 10 parts per million (ppm).

  15. Telmisartan ameliorates glutamate-induced neurotoxicity: roles of AT1 receptor blockade and PPARγ activation

    PubMed Central

    Wang, Juan; Pang, Tao; Hafko, Roman; Benicky, Julius; Sanchez-Lemus, Enrique; Saavedra, Juan M.

    2014-01-01

    Sartans (Angiotensin II AT1 Receptor Blockers, ARBs) are powerful neuroprotective agents in vivo and protect against IL-1β neurotoxicity in vitro. The purpose of this research was to determine the extent of sartan neuroprotection against glutamate excitotoxicity, a common cause of neuronal injury and apoptosis. The results show that sartans are neuroprotective, significantly reducing glutamate-induced neuronal injury and apoptosis in cultured rat primary cerebellar granule cells (CGCs). Telmisartan was the most potent sartan studied, with an order of potency telmisartan > candesartan > losartan > valsartan. Mechanisms involved reduction of pro-apoptotic caspase-3 activation, protection of the survival PI3K/Akt/GSK-3β pathway, and prevention of glutamate-induced ERK1/2 activation. NMDA receptor stimulation was essential for glutamate-induced cell injury and apoptosis. Participation of AT1A receptor was supported by glutamate-induced upregulation of AT1A gene expression and AT1 receptor binding. Conversely, AT1B or AT2 receptor played no role. Glutamate-induced neuronal injury and the neuroprotective effect of telmisartan were decreased, but not abolished, in CGCs obtained from AT1A knock-out mice. This indicates that although AT1 receptors are necessary for glutamate to exert its full neurotoxic potential, part of the neuroprotective effect of telmisartan is independent of AT1 receptor blockade. PPARγ activation was also involved in the neuroprotective effects of telmisartan, as telmisartan enhanced PPARγ nuclear translocation, and the PPARγ antagonist GW9662 partially reversed the neuroprotective effects of telmisartan. The present results substantiate the therapeutic use of sartans, in particular telmisartan, in neurodegenerative diseases and traumatic brain disorders where glutamate neurotoxicity plays a significant role. PMID:24316465

  16. PAR-2 receptor-induced effects on human eccrine sweat gland cells.

    PubMed

    L Bovell, Douglas; Kofler, Barbara; Lang, Roland

    2009-01-01

    Serine proteases can induce cell signaling by stimulating G-protein-coupled receptors, called proteinase-activated receptors (PAR's) on a variety of epithelial cells. While PAR-2, one such receptor, activates cell signaling in a secretory cell line derived from human sweat glands, there was no information on their presence and effects on intact sweat glands. PAR-2 presence and activation of eccrine sweat glands isolated from human skin samples was investigated using Western blot analysis, immunohistochemistry, electron microscopy (EM) and Ca(2+) imaging. Anti-human PAR-2 antibody demonstrated the presence of these receptors in eccrine sweat glands. EM showed that PAR-2 activation resulted in degranulation of secretory cells. Ca(2+) imaging using PAR-2 activators demonstrated a two phase increase in [Ca(2+)](i) which was dependent on extracellular Ca(2+) for the second phase, and that the response could be blocked by prior incubation with xestospongin, the IP(3) receptor blocker. The results demonstrated that PAR-2 receptors are present in human sweat gland secretory cells and that these receptors are functionally active and can induce changes associated with secretory events in eccrine glands.

  17. Peripheral and central CB1 cannabinoid receptors control stress-induced impairment of memory consolidation

    PubMed Central

    Busquets-Garcia, Arnau; Gomis-González, Maria; Srivastava, Raj Kamal; Cutando, Laura; Ortega-Alvaro, Antonio; Ruehle, Sabine; Remmers, Floortje; Bindila, Laura; Bellocchio, Luigi; Marsicano, Giovanni; Lutz, Beat; Maldonado, Rafael

    2016-01-01

    Stressful events can generate emotional memories linked to the traumatic incident, but they also can impair the formation of nonemotional memories. Although the impact of stress on emotional memories is well studied, much less is known about the influence of the emotional state on the formation of nonemotional memories. We used the novel object-recognition task as a model of nonemotional memory in mice to investigate the underlying mechanism of the deleterious effect of stress on memory consolidation. Systemic, hippocampal, and peripheral blockade of cannabinoid type-1 (CB1) receptors abolished the stress-induced memory impairment. Genetic deletion and rescue of CB1 receptors in specific cell types revealed that the CB1 receptor population specifically in dopamine β-hydroxylase (DBH)-expressing cells is both necessary and sufficient for stress-induced impairment of memory consolidation, but CB1 receptors present in other neuronal populations are not involved. Strikingly, pharmacological manipulations in mice expressing CB1 receptors exclusively in DBH+ cells revealed that both hippocampal and peripheral receptors mediate the impact of stress on memory consolidation. Thus, CB1 receptors on adrenergic and noradrenergic cells provide previously unrecognized cross-talk between central and peripheral mechanisms in the stress-dependent regulation of nonemotional memory consolidation, suggesting new potential avenues for the treatment of cognitive aspects on stress-related disorders. PMID:27528659

  18. Acetylcholine receptor extracellular domain determines sensitivity to nicotine-induced inactivation.

    PubMed

    Kuryatov, A; Olale, F A; Choi, C; Lindstrom, J

    2000-03-30

    We have shown previously that chronic exposure to submicromolar concentrations of nicotine permanently inactivates alpha4beta2 and alpha7 neuronal nicotinic acetylcholine receptors while alpha3beta2 acetylcholine receptors are resistant to inactivation. Phosphorylation of the large cytoplasmic domain has been proposed to mediate functional inactivation. Chimeric subunits consisting of human alpha4 sequence from their N-terminus to either the beginning of the first transmembrane domain or the large cytoplasmic domain and alpha3 sequences thereafter formed acetylcholine receptors with beta2 subunits which were as susceptible to nicotine-induced inactivation as wild-type alpha4 acetylcholine receptors. The converse chimeras, containing the N-terminal parts of the alpha3 subunit and the C-terminal parts of the alpha4 subunit, formed acetylcholine receptors with beta2 subunits which were as resistant to nicotine-induced inactivation as wild-type alpha3beta2 acetylcholine receptors. Thus, inactivation of acetylcholine receptors produced by chronic exposure to nicotine results primarily from effects of the agonist on the extracellular and transmembrane domains of the alpha subunit.

  19. Endomorphins 1 and 2 induce amnesia via selective modulation of dopamine receptors in mice.

    PubMed

    Ukai, Makoto; Lin, Hui Ping

    2002-06-20

    The involvement of dopamine receptors in the amnesic effects of the endogenous micro-opioid receptor agonists endomorphins 1 and 2 was investigated by observing step-down type passive avoidance learning in mice. Although the dopamine D1 receptor agonist R(+)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol hydrochloride (R(+)-SKF38393) (0.05 and 0.1 mg/kg), the dopamine D1 receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (R(+)-SCH23390) (2.5 and 5 microg/kg) or the dopamine D2 receptor agonist N-n-phenethyl-N-propylethyl-p-(3-hydroxyphenyl)-ethylamine (RU24213) (0.3 and 1 mg/kg) had no significant effects on the endomorphin-1 (10 microg)- or endomorphin-2 (10 microg)-induced decrease in step-down latency of passive avoidance learning, (-)-sulpiride (10 mg/kg), a dopamine D2 receptor antagonist, significantly reversed the decrease in step-down latency evoked by endomorphin-2 (10 microg), but not by endomorphin-1 (10 microg). Taken together, it is likely that stimulation of dopamine D2 receptors results in the endomorphin-2-but not endomorphin-1-induced impairment of passive avoidance learning.

  20. The transforming growth factor beta type II receptor can replace the activin type II receptor in inducing mesoderm.

    PubMed Central

    Bhushan, A; Lin, H Y; Lodish, H F; Kintner, C R

    1994-01-01

    The type II receptors for the polypeptide growth factors transforming growth factor beta (TGF-beta) and activin belong to a new family of predicted serine/threonine protein kinases. In Xenopus embryos, the biological effects of activin and TGF-beta 1 are strikingly different; activin induces a full range of mesodermal cell types in the animal cap assay, while TGF-beta 1 has no effects, presumably because of the lack of functional TGF-beta receptors. In order to assess the biological activities of exogenously added TGF-beta 1, RNA encoding the TGF-beta type II receptor was introduced into Xenopus embryos. In animal caps from these embryos, TGF-beta 1 and activin show similar potencies for induction of mesoderm-specific mRNAs, and both elicit the same types of mesodermal tissues. In addition, the response of animal caps to TGF-beta 1, as well as to activin, is blocked by a dominant inhibitory ras mutant, p21(Asn-17)Ha-ras. These results indicate that the activin and TGF-beta type II receptors can couple to similar signalling pathways and that the biological specificities of these growth factors lie in their different ligand-binding domains and in different competences of the responding cells. Images PMID:8196664

  1. Optimal T-cell receptor affinity for inducing autoimmunity

    PubMed Central

    Koehli, Sabrina; Naeher, Dieter; Galati-Fournier, Virginie; Zehn, Dietmar; Palmer, Ed

    2014-01-01

    T-cell receptor affinity for self-antigen has an important role in establishing self-tolerance. Three transgenic mouse strains expressing antigens of variable affinity for the OVA transgenic-I T-cell receptor were generated to address how TCR affinity affects the efficiency of negative selection, the ability to prime an autoimmune response, and the elimination of the relevant target cell. Mice expressing antigens with an affinity just above the negative selection threshold exhibited the highest risk of developing experimental autoimmune diabetes. The data demonstrate that close to the affinity threshold for negative selection, sufficient numbers of self-reactive T cells escape deletion and create an increased risk for the development of autoimmunity. PMID:25411315

  2. Green-Light-Induced Inactivation of Receptor Signaling Using Cobalamin-Binding Domains.

    PubMed

    Kainrath, Stephanie; Stadler, Manuela; Reichhart, Eva; Distel, Martin; Janovjak, Harald

    2017-04-10

    Optogenetics and photopharmacology provide spatiotemporally precise control over protein interactions and protein function in cells and animals. Optogenetic methods that are sensitive to green light and can be used to break protein complexes are not broadly available but would enable multichromatic experiments with previously inaccessible biological targets. Herein, we repurposed cobalamin (vitamin B12) binding domains of bacterial CarH transcription factors for green-light-induced receptor dissociation. In cultured cells, we observed oligomerization-induced cell signaling for the fibroblast growth factor receptor 1 fused to cobalamin-binding domains in the dark that was rapidly eliminated upon illumination. In zebrafish embryos expressing fusion receptors, green light endowed control over aberrant fibroblast growth factor signaling during development. Green-light-induced domain dissociation and light-inactivated receptors will critically expand the optogenetic toolbox for control of biological processes.

  3. Ethanol-induced developmental neurodegeneration in secretin receptor-deficient mice.

    PubMed

    Hwang, Dong-Woo; Givens, Bennet; Nishijima, Ichiko

    2009-05-06

    Alcohol exposure during brain development induces neuronal cell death in the brain. Several neuroactive peptides have been shown to protect against alcohol-induced cell death. Secretin is a peptide hormone, and the secretin receptor is expressed in the gut and the brain. To explore a potential role of secretin signal against ethanol neurotoxicity during brain development, secretin receptor-deficient mice were exposed to ethanol on postnatal day 4. We identified significant ethanol-induced apoptosis in the external granular layer of the secretin receptor-deficient cerebellum and in the striatum after ethanol treatment. During the early postnatal period, there is a proliferation of granular cell progenitors that reside in the external granular layer. The results suggest that secretin signal plays a neuroprotective role of neuronal progenitor cells against the neurotoxicity of ethanol.

  4. Involvement of tyrosine residues located in the carboxyl tail of the human beta 2-adrenergic receptor in agonist-induced down-regulation of the receptor.

    PubMed Central

    Valiquette, M; Bonin, H; Hnatowich, M; Caron, M G; Lefkowitz, R J; Bouvier, M

    1990-01-01

    Chronic exposure of various cell types to adrenergic agonists leads to a decrease in cell surface beta 2-adrenergic receptor (beta 2AR) number. Sequestration of the receptor away from the cell surface as well as a down-regulation of the total number of cellular receptors are believed to contribute to this agonist-mediated regulation of receptor number. However, the molecular mechanisms underlying these phenomena are not well characterized. Recently, tyrosine residues located in the cytoplasmic tails of several membrane receptors, such as the low density lipoprotein and mannose-6-phosphate receptors, have been suggested as playing an important role in the agonist-induced internalization of these receptors. Accordingly, we assessed the potential role of two tyrosine residues in the carboxyl tail of the human beta 2AR in agonist-induced sequestration and down-regulation of the receptor. Tyr-350 and Tyr-354 of the human beta 2AR were replaced with alanine residues by site-directed mutagenesis and both wild-type and mutant beta 2AR were stably expressed in transformed Chinese hamster fibroblasts. The mutation dramatically decreased the ability of the beta 2AR to undergo isoproterenol-induced down-regulation. However, the substitution of Tyr-350 and Tyr-354 did not affect agonist-induced sequestration of the receptor. These results suggest that tyrosine residues in the cytoplasmic tail of human beta 2AR are crucial determinants involved in its down-regulation. PMID:2164220

  5. Drug-induced graves disease from CTLA-4 receptor suppression.

    PubMed

    Borodic, Gary; Hinkle, David M; Cia, Yihong

    2011-01-01

    Monoclonal antibody, ipilimumab, useful for treatment of metastatic melanoma, blocks CTLA-4 mediated T-cell suppression and can also cause a Graves ophthalmopathy like syndrome. Epidemiologic study has linked variant polymorphisms of CTLA-4 receptor gene to the presence of thyroid eye disease. The combination of these observations suggests CTLA-4 mediated T-cell functions are important to the pathogenesis of thyroid-associated eye disease.

  6. Doxorubicin induces cardiotoxicity through upregulation of death receptors mediated apoptosis in cardiomyocytes

    PubMed Central

    Zhao, Liqun; Zhang, Baolin

    2017-01-01

    Doxorubicin is a highly effective anticancer agent but causes cardiotoxicity in many patients. The mechanisms of doxorubicin-induced cardiotoxicity remain incompletely understood. Here we investigated doxorubicin-induced cytotoxicity in human induced pluripotent stem cells-derived cardiomyocytes (iPS-CMs). We found that doxorubicin and related anthracycline agents (e.g., daunorubicin, idarubicin, and epirubicin) significantly upregulated the expression of death receptors (DRs) (TNFR1, Fas, DR4 and DR5) in iPS-derived cardiomyocytes at both protein and mRNA levels. The resulting iPS-CMs cells underwent spontaneous apoptosis which was further enhanced by physiologically relevant death ligands including TNF-related apoptosis inducing ligand (TRAIL). Furthermore, TRAIL potentiated doxorubicin-induced decrease in beating rate and amplitude of iPS-derived cardiomyocytes. These data demonstrate that the induction of death receptors in cardiomyocytes is likely a critical mechanism by which doxorubicin causes cardiotoxicity. PMID:28300219

  7. GLP-1 receptor agonist-induced polyarthritis: a case report.

    PubMed

    Ambrosio, Maria Luisa; Monami, Matteo; Sati, Lavinia; Marchionni, Niccolò; Di Bari, Mauro; Mannucci, Edoardo

    2014-08-01

    Occasional cases of bilateral, symmetrical, seronegative polyarthritis have been reported in patients treated with dipeptidyl peptidase-4 inhibitors (Crickx et al. in Rheumatol Int, 2013). We report here a similar case observed during treatment with a GLP-1 receptor agonist. A 42-year-old man with type 2 diabetes treated with metformin 1,500 mg/day and liraglutide 1.8 mg/day. After 6 months from the beginning of treatment, the patient complained of bilateral arthralgia (hands, feet, ankles, knees, and hips). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and leukocytes were increased. Rheumatoid factor, anticyclic citrullinated protein antibody, antinuclear antibodies, anti-Borrelia, and burgdorferi antibodies were all negative, and myoglobin and calcitonin were normal. Liraglutide was withdrawn, and the symptoms completely disappeared within 1 week, with normalization of ESR, CRP, fibrinogen, and leukocytes. Previously described cases of polyarthritis associated with DPP4 inhibitors had been attributed to a direct effect of the drugs on inflammatory cells expressing the enzyme. The present case, occurred during treatment with a GLP-1 receptor agonists, suggests a possibly different mechanism, mediated by GLP-1 receptor stimulation, which deserved further investigation.

  8. Adenosine-A1 receptor agonist induced hyperalgesic priming type II.

    PubMed

    Araldi, Dioneia; Ferrari, Luiz F; Levine, Jon D

    2016-03-01

    We have recently shown that repeated exposure of the peripheral terminal of the primary afferent nociceptor to the mu-opioid receptor (MOR) agonist DAMGO ([D-Ala, N-Me-Phe, Gly-ol]-enkephalin acetate salt) induces a model of transition to chronic pain that we have termed type II hyperalgesic priming. Similar to type I hyperalgesic priming, there is a markedly prolonged response to subsequent administration of proalgesic cytokines, prototypically prostaglandin E2 (PGE2). However, type II hyperalgesic priming differs from type I in being rapidly induced, protein kinase A (PKA), rather than PKCε dependent, not reversed by a protein translation inhibitor, occurring in female as well as in male rats, and isolectin B4-negative neuron dependent. We report that, as with the repeated injection of a MOR agonist, the repeated administration of an agonist at the A1-adenosine receptor, also a Gi-protein coupled receptor, N-cyclopentyladenosine (CPA), also produces priming similar to DAMGO-induced type II hyperalgesic priming. In this study, we demonstrate that priming induced by repeated exposure to this A1-adenosine receptor agonist shares the same mechanisms, as MOR-agonist induced priming. However, the prolongation of PGE2 hyperalgesia induced by repeated administration of CPA depends on G-protein αi subunit activation, differently from DAMGO-induced type II priming, in which it depends on the β/γ subunit. These data implicate a novel form of Gi-protein signaling pathway in the type II hyperalgesic priming induced by repeated administration of an agonist at A1-adenosine receptor to the peripheral terminal of the nociceptor.

  9. Adenosine-A1 Receptor Agonist Induced Hyperalgesic Priming Type II

    PubMed Central

    Araldi, Dioneia; Ferrari, Luiz F.; Levine, Jon D.

    2016-01-01

    We have recently shown that repeated exposure of the peripheral terminal of the primary afferent nociceptor to the mu-opioid receptor (MOR) agonist DAMGO ([D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin acetate salt) induces a model of the transition to chronic pain that we have termed Type II hyperalgesic priming. Similar to Type I hyperalgesic priming, there is a markedly prolonged response to subsequent administration of proalgesic cytokines, prototypically prostaglandin E2 (PGE2). However, Type II hyperalgesic priming differs from Type I in being rapidly induced, protein kinase A (PKA), rather than PKCε dependent, not reversed by a protein translation inhibitor, occurring in female as well as in male rats, and isolectin B4-negative neuron dependent. We report that as with the repeated injection of a MOR agonist, the repeated administration of an agonist at the A1-adenosine receptor, also a Gi-protein coupled receptor, N6-Cyclopentyladenosine (CPA), also produces priming similar to DAMGO-induced Type II hyperalgesic priming. In this study we demonstrate that priming induced by repeated exposure to this A1-adenosine receptor agonist shares the same mechanisms as MOR-agonist induced priming. However, the prolongation of PGE2 hyperalgesia induced by repeated administration of CPA depends on G-protein αi subunit activation, differently from DAMGO-induced Type II priming, in which it depends on the β/γ subunit. These data implicate a novel form of Gi-protein signaling pathway in the Type II hyperalgesic priming induced by repeated administration of an agonist at A1-adenosine receptor to the peripheral terminal of the nociceptor. PMID:26588695

  10. Peripheral NMDA Receptors Mediate Antidromic Nerve Stimulation-Induced Tactile Hypersensitivity in the Rat.

    PubMed

    Jang, Jun Ho; Nam, Taick Sang; Jun, Jaebeom; Jung, Se Jung; Kim, Dong-Wook; Leem, Joong Woo

    2015-01-01

    We investigated the role of peripheral NMDA receptors (NMDARs) in antidromic nerve stimulation-induced tactile hypersensitivity outside the skin area innervated by stimulated nerve. Tetanic electrical stimulation (ES) of the decentralized L5 spinal nerve, which induced enlargement of plasma extravasation, resulted in tactile hypersensitivity in the L4 plantar dermatome of the hind-paw. When intraplantar (i.pl.) injection was administered into the L4 dermatome before ES, NMDAR and group-I metabotropic Glu receptor (mGluR) antagonists and group-II mGluR agonist but not AMPA/kainate receptor antagonist prevented ES-induced hypersensitivity. I.pl. injection of PKA or PKC inhibitors also prevented ES-induced hypersensitivity. When the same injections were administered after establishment of ES-induced hypersensitivity, hypersensitivity was partially reduced by NMDAR antagonist only. In naïve animals, i.pl. Glu injection into the L4 dermatome induced tactile hypersensitivity, which was blocked by NMDAR antagonist and PKA and PKC inhibitors. These results suggest that the peripheral release of Glu, induced by antidromic nerve stimulation, leads to the expansion of tactile hypersensitive skin probably via nociceptor sensitization spread due to the diffusion of Glu into the skin near the release site. In addition, intracellular PKA- and PKC-dependent mechanisms mediated mainly by NMDAR activation are involved in Glu-induced nociceptor sensitization and subsequent hypersensitivity.

  11. Activation of GABA-A Receptor Ameliorates Homocysteine-Induced MMP-9 Activation by ERK Pathway

    PubMed Central

    TYAGI, NEETU; GILLESPIE, WILLIAM; VACEK, JONATHAN C.; SEN, UTPAL; TYAGI, SURESH C.; LOMINADZE, DAVID

    2010-01-01

    Hyperhomocysteinemia (HHcy) is a risk factor for neuroinflammatory and neurodegenerative diseases. Homocysteine (Hcy) induces redox stress, in part, by activating matrix metalloproteinase-9 (MMP-9), which degrades the matrix and leads to blood–brain barrier dysfunction. Hcy competitively binds to γ-aminbutyric acid (GABA) receptors, which are excitatory neurotransmitter receptors. However, the role of GABA-A receptor in Hcy-induced cerebrovascular remodeling is not clear. We hypothesized that Hcy causes cerebrovascular remodeling by increasing redox stress and MMP-9 activity via the extracellular signal-regulated kinase (ERK) signaling pathway and by inhibition of GABA-A receptors, thus behaving as an inhibitory neurotransmitter. Hcy-induced reactive oxygen species production was detected using the fluorescent probe, 2′–7′-dichlorodihydrofluorescein diacetate. Hcy increased nicotinamide adenine dinucleotide phosphate-oxidase-4 concomitantly suppressing thioredoxin. Hcy caused activation of MMP-9, measured by gelatin zymography. The GABA-A receptor agonist, muscimol ameliorated the Hcy-mediated MMP-9 activation. In parallel, Hcy caused phosphorylation of ERK and selectively decreased levels of tissue inhibitors of metalloproteinase-4 (TIMP-4). Treatment of the endothelial cell with muscimol restored the levels of TIMP-4 to the levels in control group. Hcy induced expression of iNOS and decreased eNOS expression, which lead to a decreased NO bioavailability. Furthermore muscimol attenuated Hcy-induced MMP-9 via ERK signaling pathway. These results suggest that Hcy competes with GABA-A receptors, inducing the oxidative stress transduction pathway and leading to ERK activation. PMID:19308943

  12. Toll-like receptor 4 promotes fibrosis in bleomycin-induced lung injury in mice.

    PubMed

    Li, X X; Jiang, D Y; Huang, X X; Guo, S L; Yuan, W; Dai, H P

    2015-12-21

    The specific role of Toll-like receptor 4 (TLR4) in bleomycin-induced lung fibrosis of mice, a model of human idiopathic pulmonary fibrosis, has not been characterized. We injected bleomycin intratracheally into TLR4 knockout (TLR4(-/-)) and wild-type (WT) mice. Twenty-one days after injection, mice were sacrificed and their lungs were harvested for pathological, hydroxyproline, mRNA expression, and collagen I analyses. Body weight changes and mortality were observed. Light microscopy showed that lung fibrosis was minimal in TLR4(-/-) compared to that in WT mice on day 21 after bleomycin instillation. The Ashcroft score was significantly lower in TLR4(-/-) than in WT mice (3.667 ± 0.730 vs 4.945 ± 0.880, P < 0.05). Hydroxyproline content was significantly lower in TLR4(-/-) than in WT mice on day 21 after bleomycin injection (0.281 ± 0.022 vs 0.371 ± 0.047, P < 0.05). Compared to WT mice, bleomycin-treated TLR4(-/-) mice expressed significantly lower type I collagen mRNA levels (mesenchymal marker; 11.069 ± 2.627 vs 4.589 ± 1.440, P < 0.05). Collagen I was significantly lower in TLR4(-/-) than in WT mice (0.838 ± 0.352 vs 2.427 ± 0.551, P < 0.05). Bleomycin-treated TLR4(-/-) mice had a significantly lower mortality rate on day 21 than WT mice (33 vs 75%, P < 0.05). Body weight reduction was lower in TLR4(-/-) mice than in WT mice; this difference was not statistically significant (-3.735 ± 5.276 vs -6.698 ± 3.218, P > 0.05). Thus, bleomycin-induced pulmonary fibrosis is TLR4-dependent and TLR4 promoted fibrosis in bleomycin-challenged mice.

  13. Visualization and ligand-induced modulation of dopamine receptor dimerization at the single molecule level

    PubMed Central

    Tabor, Alina; Weisenburger, Siegfried; Banerjee, Ashutosh; Purkayastha, Nirupam; Kaindl, Jonas M.; Hübner, Harald; Wei, Luxi; Grömer, Teja W.; Kornhuber, Johannes; Tschammer, Nuska; Birdsall, Nigel J. M.; Mashanov, Gregory I.; Sandoghdar, Vahid; Gmeiner, Peter

    2016-01-01

    G protein–coupled receptors (GPCRs), including dopamine receptors, represent a group of important pharmacological targets. An increased formation of dopamine receptor D2 homodimers has been suggested to be associated with the pathophysiology of schizophrenia. Selective labeling and ligand-induced modulation of dimerization may therefore allow the investigation of the pathophysiological role of these dimers. Using TIRF microscopy at the single molecule level, transient formation of homodimers of dopamine receptors in the membrane of stably transfected CHO cells has been observed. The equilibrium between dimers and monomers was modulated by the binding of ligands; whereas antagonists showed a ratio that was identical to that of unliganded receptors, agonist-bound D2 receptor-ligand complexes resulted in an increase in dimerization. Addition of bivalent D2 receptor ligands also resulted in a large increase in D2 receptor dimers. A physical interaction between the protomers was confirmed using high resolution cryogenic localization microscopy, with ca. 9 nm between the centers of mass. PMID:27615810

  14. Stress-induced alterations in 5-HT1A receptor transcriptional modulators NUDR and Freud-1.

    PubMed

    Szewczyk, Bernadeta; Kotarska, Katarzyna; Daigle, Mireille; Misztak, Paulina; Sowa-Kucma, Magdalena; Rafalo, Anna; Curzytek, Katarzyna; Kubera, Marta; Basta-Kaim, Agnieszka; Nowak, Gabriel; Albert, Paul R

    2014-11-01

    The effect of stress on the mRNA and protein level of the 5-HT1A receptor and two of its key transcriptional modulators, NUDR and Freud-1, was examined in the prefrontal cortex (PFC) and hippocampus (Hp) using rodent models: olfactory bulbectomy (OB) and prenatal stress (PS) in male and female rats; chronic mild stress in male rats (CMS) and pregnancy stress. In PFC, CMS induced the most widespread changes, with significant reduction in both mRNA and protein levels of NUDR, 5-HT1A receptor and in Freud-1 mRNA; while in Hp 5-HT1A receptor and Freud-1 protein levels were also decreased. In male, but not female OB rats PFC Freud-1 and 5-HT1A receptor protein levels were reduced, while in Hp 5-HT1A receptor, Freud-1 and NUDR mRNA's but not protein were reduced. In PS rats PFC 5-HT1A receptor protein was reduced more in females than males; while in Hp Freud-1 protein was increased in females. In pregnancy stress, PFC NUDR, Freud-1 and 5-HT1A protein receptor levels were reduced, and in HP 5-HT1A receptor protein levels were also reduced; in HP only NUDR and Freud-1 mRNA levels were reduced. Overall, CMS and stress during pregnancy produced the most salient changes in 5-HT1A receptor and transcription factor expression, suggesting a primary role for altered transcription factor expression in chronic regulation of 5-HT1A receptor expression. By contrast, OB (in males) and PS (in females) produced gender-specific reductions in PFC 5-HT1A receptor protein levels, suggesting a role for post-transcriptional regulation. These and previous data suggest that chronic stress might be a key regulator of NUDR/Freud-1 gene expression.

  15. Stress-induced alterations in 5-HT1A receptor transcriptional modulators NUDR and Freud-1

    PubMed Central

    Szewczyk, Bernadeta; Kotarska, Katarzyna; Daigle, Mireille; Misztak, Paulina; Sowa-Kucma, Magdalena; Rafalo, Anna; Curzytek, Katarzyna; Kubera, Marta; Basta-Kaim, Agnieszka; Nowak, Gabriel; Albert, Paul R

    2015-01-01

    The effect of stress on the mRNA and protein level of the 5-HT1A receptor and two of its key transcriptional modulators, NUDR and Freud-1, was examined in the prefrontal cortex (PFC) and hippocampus (Hp) using rodent models: olfactory bulbectomy (OB) and prenatal stress (PS) in male and female rats; chronic mild stress in male rats (CMS) and pregnancy stress. In PFC, CMS induced the most widespread changes, with significant reduction in both mRNA and protein levels of NUDR, 5-HT1A receptor and in Freud-1 mRNA; while in Hp 5-HT1A receptor and Freud-1 protein levels were also decreased. In male, but not female OB rats PFC Freud-1 and 5-HT1A receptor protein levels were reduced, while in Hp 5-HT1A receptor, Freud-1 and NUDR mRNA’s but not protein were reduced. In PS rats PFC 5-HT1A receptor protein was reduced more in females than males; while in Hp Freud-1 protein was increased in females. In pregnancy stress, PFC NUDR, Freud-1 and 5-HT1A protein receptor levels were reduced, and in HP 5-HT1A receptor protein levels were also reduced; in HP only NUDR and Freud-1 mRNA levels were reduced. Overall, CMS and stress during pregnancy produced the most salient changes in 5-HT1A receptor and transcription factor expression, suggesting a primary role for altered transcription factor expression in chronic regulation of 5-HT1A receptor expression. By contrast, OB (in males) and PS (in females) produced gender-specific reductions in PFC 5-HT1A receptor protein levels, suggesting a role for post-transcriptional regulation. These and previous data suggest that chronic stress might be a key regulator of NUDR/Freud-1 gene expression. PMID:24946016

  16. A semisynthetic Eph receptor tyrosine kinase provides insight into ligand-induced kinase activation

    PubMed Central

    Singla, Nikhil; Erdjument-Bromage, Hediye; Himanen, Juha P.; Muir, Tom W.; Nikolov, Dimitar B.

    2011-01-01

    SUMMARY We have developed a methodology for generating milligram amounts of functional Eph tyrosine kinase receptor using the protein engineering approach of expressed protein ligation. Stimulation with ligand induces efficient autophosphorylation of the semisynthetic Eph construct. The in vitro phosphorylation of key Eph tyrosine residues upon ligand-induced activation was monitored via time-resolved, quantitative phosphoproteomics, suggesting a precise and unique order of phosphorylation of the Eph tyrosines in the kinase activation process. To our knowledge, this work represents the first reported semisynthesis of a receptor tyrosine kinase and provides a potentially general method for producing single-pass membrane proteins for structural and biochemical characterization. PMID:21439481

  17. Phorbol ester-induced serine phosphorylation of the insulin receptor decreases its tyrosine kinase activity.

    PubMed

    Takayama, S; White, M F; Kahn, C R

    1988-03-05

    The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the function of the insulin receptor was examined in intact hepatoma cells (Fao) and in solubilized extracts purified by wheat germ agglutinin chromatography. Incubation of ortho[32P]phosphate-labeled Fao cells with TPA increased the phosphorylation of the insulin receptor 2-fold after 30 min. Analysis of tryptic phosphopeptides from the beta-subunit of the receptor by reverse-phase high performance liquid chromatography and determination of their phosphoamino acid composition suggested that TPA predominantly stimulated phosphorylation of serine residues in a single tryptic peptide. Incubation of the Fao cells with insulin (100 nM) for 1 min stimulated 4-fold the phosphorylation of the beta-subunit of the insulin receptor. Prior treatment of the cells with TPA inhibited the insulin-stimulated tyrosine phosphorylation by 50%. The receptors extracted with Triton X-100 from TPA-treated Fao cells and purified on immobilized wheat germ agglutinin retained the alteration in kinase activity and exhibited a 50% decrease in insulin-stimulated tyrosine autophosphorylation and phosphotransferase activity toward exogenous substrates. This was due primarily to a decrease in the Vmax for these reactions. TPA treatment also decreased the Km of the insulin receptor for ATP. Incubation of the insulin receptor purified from TPA-treated cells with alkaline phosphatase decreased the phosphate content of the beta-subunit to the control level and reversed the inhibition, suggesting that the serine phosphorylation of the beta-subunit was responsible for the decreased tyrosine kinase activity. Our results support the notion that the insulin receptor is a substrate for protein kinase C in the Fao cell and that the increase in serine phosphorylation of the beta-subunit of the receptor produced by TPA treatment inhibited tyrosine kinase activity in vivo and in vitro. These data suggest that protein kinase C may regulate the function

  18. Lysergic acid diethylamide-induced Fos expression in rat brain: role of serotonin-2A receptors.

    PubMed

    Gresch, P J; Strickland, L V; Sanders-Bush, E

    2002-01-01

    Lysergic acid diethylamide (LSD) produces altered mood and hallucinations in humans and binds with high affinity to serotonin-2A (5-HT(2A)) receptors. Although LSD interacts with other receptors, the activation of 5-HT(2A) receptors is thought to mediate the hallucinogenic properties of LSD. The goal of this study was to identify the brain sites activated by LSD and to determine the influence of 5-HT(2A) receptors in this activation. Rats were pretreated with the 5-HT(2A) receptor antagonist MDL 100907 (0.3 mg/kg, i.p.) or vehicle 30 min prior to LSD (500 microg/kg, i.p.) administration and killed 3 h later. Brain tissue was examined for Fos protein expression by immunohistochemistry. LSD administration produced a five- to eight-fold increase in Fos-like immunoreactivity in medial prefrontal cortex, anterior cingulate cortex, and central nucleus of amygdala. However, in dorsal striatum and nucleus accumbens no increase in Fos-like immunoreactivity was observed. Pretreatment with MDL 100907 completely blocked LSD-induced Fos-like immunoreactivity in medial prefrontal cortex and anterior cingulate cortex, but only partially blocked LSD-induced Fos-like immunoreactivity in amygdala. Double-labeled immunohistochemistry revealed that LSD did not induce Fos-like immunoreactivity in cortical cells expressing 5-HT(2A) receptors, suggesting an indirect activation of cortical neurons. These results indicate that the LSD activation of medial prefrontal cortex and anterior cingulate cortex is mediated by 5-HT(2A) receptors, whereas in amygdala 5-HT(2A) receptor activation is a component of the response. These findings support the hypothesis that the medial prefrontal cortex, anterior cingulate cortex, and perhaps the amygdala, are important regions involved in the production of hallucinations.

  19. Overexpression of the dopamine D3 receptor in the rat dorsal striatum induces dyskinetic behaviors.

    PubMed

    Cote, Samantha R; Chitravanshi, Vineet C; Bleickardt, Carina; Sapru, Hreday N; Kuzhikandathil, Eldo V

    2014-04-15

    L-DOPA-induced dyskinesias (LID) are motor side effects associated with treatment of Parkinson's disease (PD). The etiology of LID is not clear; however, studies have shown that the dopamine D3 receptor is upregulated in the basal ganglia of mice, rats and non-human primate models of LID. It is not known if the upregulation of D3 receptor is a cause or result of LID. In this paper we tested the hypothesis that overexpression of the dopamine D3 receptor in dorsal striatum, in the absence of dopamine depletion, will elicit LID. Replication-deficient recombinant adeno-associated virus-2 expressing the D3 receptor or enhanced green fluorescent protein (EGFP) were stereotaxically injected, unilaterally, into the dorsal striatum of adult rats. Post-hoc immunohistochemical analysis revealed that ectopic expression of the D3 receptor was limited to neurons near the injection sites in the dorsal striatum. Following a 3-week recovery period, rats were administered saline, 6 mg/kg L-DOPA, 0.1 mg/kg PD128907 or 10 mg/kg ES609, i.p., and motor behaviors scored. Rats overexpressing the D3 receptor specifically exhibited contralateral axial abnormal involuntary movements (AIMs) following administration of L-DOPA and PD128907 but not saline or the novel agonist ES609. Daily injection of 6 mg/kg L-DOPA to the rats overexpressing the D3 receptor also caused increased vacuous chewing behavior. These results suggest that overexpression of the D3 receptor in the dorsal striatum results in the acute expression of agonist-induced axial AIMs and chronic L-DOPA-induced vacuous chewing behavior. Agonists such as ES609 might provide a novel therapeutic approach to treat dyskinesia.

  20. MLN64 induces mitochondrial dysfunction associated with increased mitochondrial cholesterol content.

    PubMed

    Balboa, Elisa; Castro, Juan; Pinochet, María-José; Cancino, Gonzalo I; Matías, Nuria; José Sáez, Pablo; Martínez, Alexis; Álvarez, Alejandra R; Garcia-Ruiz, Carmen; Fernandez-Checa, José C; Zanlungo, Silvana

    2017-03-02

    MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH) levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria.

  1. Diet-induced regulation of bitter taste receptor subtypes in the mouse gastrointestinal tract.

    PubMed

    Vegezzi, Gaia; Anselmi, Laura; Huynh, Jennifer; Barocelli, Elisabetta; Rozengurt, Enrique; Raybould, Helen; Sternini, Catia

    2014-01-01

    Bitter taste receptors and signaling molecules, which detect bitter taste in the mouth, are expressed in the gut mucosa. In this study, we tested whether two distinct bitter taste receptors, the bitter taste receptor 138 (T2R138), selectively activated by isothiocyanates, and the broadly tuned bitter taste receptor 108 (T2R108) are regulated by luminal content. Quantitative RT-PCR analysis showed that T2R138 transcript is more abundant in the colon than the small intestine and lowest in the stomach, whereas T2R108 mRNA is more abundant in the stomach compared to the intestine. Both transcripts in the stomach were markedly reduced by fasting and restored to normal levels after 4 hours re-feeding. A cholesterol-lowering diet, mimicking a diet naturally low in cholesterol and rich in bitter substances, increased T2R138 transcript, but not T2R108, in duodenum and jejunum, and not in ileum and colon. Long-term ingestion of high-fat diet increased T2R138 RNA, but not T2R108, in the colon. Similarly, α-gustducin, a bitter taste receptor signaling molecule, was reduced by fasting in the stomach and increased by lowering cholesterol in the small intestine and by high-fat diet in the colon. These data show that both short and long term changes in the luminal contents alter expression of bitter taste receptors and associated signaling molecules in the mucosa, supporting the proposed role of bitter taste receptors in luminal chemosensing in the gastrointestinal tract. Bitter taste receptors might serve as regulatory and defensive mechanism to control gut function and food intake and protect the body from the luminal environment.

  2. Retinoids induce integrin-independent lymphocyte adhesion through RAR-α nuclear receptor activity

    SciTech Connect

    Whelan, Jarrett T.; Wang, Lei; Chen, Jianming; Metts, Meagan E.; Nasser, Taj A.; McGoldrick, Liam J.; Bridges, Lance C.

    2014-11-28

    Highlights: • Transcription and translation are required for retinoid-induced lymphocyte adhesion. • RAR activation is sufficient to induced lymphocyte cell adhesion. • Vitamin D derivatives inhibit RAR-prompted lymphocyte adhesion. • Adhesion occurs through a novel binding site within ADAM disintegrin domains. • RARα is a key nuclear receptor for retinoid-dependent lymphocyte cell adhesion. - Abstract: Oxidative metabolites of vitamin A, in particular all-trans-retinoic acid (atRA), have emerged as key factors in immunity by specifying the localization of immune cells to the gut. Although it is appreciated that isomers of retinoic acid activate the retinoic acid receptor (RAR) and retinoid X receptor (RXR) family of nuclear receptors to elicit cellular changes, the molecular details of retinoic acid action remain poorly defined in immune processes. Here we employ a battery of agonists and antagonists to delineate the specific nuclear receptors utilized by retinoids to evoke lymphocyte cell adhesion to ADAM (adisintegrin and metalloprotease) protein family members. We report that RAR agonism is sufficient to promote immune cell adhesion in both immortal and primary immune cells. Interestingly, adhesion occurs independent of integrin function, and mutant studies demonstrate that atRA-induced adhesion to ADAM members required a distinct binding interface(s) as compared to integrin recognition. Anti-inflammatory corticosteroids as well as 1,25-(OH){sub 2}D{sub 3}, a vitamin D metabolite that prompts immune cell trafficking to the skin, potently inhibited the observed adhesion. Finally, our data establish that induced adhesion was specifically attributable to the RAR-α receptor isotype. The current study provides novel molecular resolution as to which nuclear receptors transduce retinoid exposure into immune cell adhesion.

  3. Ghrelin Receptor Deficiency does not Affect Diet-Induced Atherosclerosis in Low-Density Lipoprotein Receptor-Null Mice

    PubMed Central

    Habegger, Kirk M.; Grant, Erin; Pfluger, Paul Thomas; Perez-Tilve, Diego; Daugherty, Alan; Bruemmer, Dennis; Tschöp, Matthias H.; Hofmann, Susanna M.

    2011-01-01

    Objective: Ghrelin, a stomach-derived, secreted peptide, and its receptor (growth hormone secretagogue receptor, GHSR) are known to modulate food intake and energy homeostasis. The ghrelin system is also expressed broadly in cardiovascular tissues. Since ghrelin has been associated with anti-inflammatory and anti-atherogenic properties, but is also well known to promote obesity and impair glucose metabolism, we investigated whether ghrelin has any impact on the development of atherosclerosis. The hypothesis that endogenous ghrelin signaling may be involved in atherosclerosis has not been tested previously. Methods and Results: We crossed ghrelin receptor knockout mice (GHSr−/−) into a low-density lipoprotein receptor-null (Ldlr−/−) mouse line. In this model, atherosclerotic lesions were promoted by feeding a high-fat, high-cholesterol Western-type diet for 13 months, following a standard protocol. Body composition and glucose homeostasis were similar between Ldlr−/− and Ldlr/GHSR−/−ko mice throughout the study. Absence or presence of GHSr did not alter the apolipoprotein profile changes in response to diet exposure on an LDLRko background. Atherosclerotic plaque volume in the aortic arch and thoracic aorta were also not affected differentially in mice without ghrelin signaling due to GHSR gene disruption as compared to control LDLRko littermates. In light of the associations reported for ghrelin with cardiovascular disease in humans, the lack of a phenotype in these loss-of-function studies in mice suggests no direct role for endogenous ghrelin in either the inhibition or the promotion of diet-induced atherosclerosis. Conclusion: These data indicate that, surprisingly, the complex and multifaceted actions of endogenous ghrelin receptor mediated signaling on the cardiovascular system have minimal direct impact on atherosclerotic plaque progression as based on a loss-of-function mouse model of the disease. PMID:22649381

  4. From Chemotherapy-Induced Emesis to Neuroprotection: Therapeutic Opportunities for 5-HT3 Receptor Antagonists.

    PubMed

    Fakhfouri, Gohar; Mousavizadeh, Kazem; Mehr, Sharam Ejtemaei; Dehpour, Ahmad Reza; Zirak, Mohammad Reza; Ghia, Jean-Eric; Rahimian, Reza

    2015-12-01

    5-HT3 receptor antagonists are extensively used as efficacious agents in counteracting chemotherapy-induced emesis. Recent investigations have shed light on other potential effects (analgesic, anxiolytic, and anti-psychotic). Some studies have reported neuroprotective properties for the 5-HT3 receptor antagonists in vitro and in vivo. When administered to Aβ-challenged rat cortical neurons, 5-HT3 receptor antagonists substantially abated apoptosis, elevation of cytosolic Ca(2), glutamate release, reactive oxygen species (ROS) generation, and caspase-3 activity. In addition, in vivo studies show that 5-HT3 receptor antagonists possess, alongside their anti-emetic effects, notable immunomodulatory properties in CNS. We found that pretreatment with tropisetron significantly improved neurological deficits and diminished leukocyte transmigration into the brain, TNF-α level, and brain infarction in a murine model of embolic stroke. Our recent investigation revealed that tropisetron protects against Aβ-induced neurotoxicity in vivo through both 5-HT3 receptor-dependent and -independent pathways. Tropisetron, in vitro, was found to be an efficacious inhibitor of the signaling pathway leading to the activation of pro-inflammatory NF-κB, a transcription factor pivotal to the upregulation of several neuroinflammatory mediators in brain. This mini review summarizes novel evidence concerning effects of 5-HT3 antagonists and their possible mechanisms of action in ameliorating neurodegenerative diseases including Alzheimer, multiple sclerosis, and stroke. Further, we discuss some newly synthesized 5-HT3 receptor antagonists with dual properties of 5-HT3 receptor blockade/alpha-7 nicotinic receptor activator and their potential in management of memory impairment. Since 5-HT3 receptor antagonists possess a large therapeutic window, they can constitute a scaffold for design and synthesis of new neuroprotective medications.

  5. Modification of formalin-induced nociception by different histamine receptor agonists and antagonists.

    PubMed

    Farzin, Davood; Nosrati, Farnaz

    2007-01-15

    The present study evaluated the effects of different histamine receptor agonists and antagonists on the nociceptive response in the mouse formalin test. Intracerebroventricular (20-40 microg/mouse i.c.v.) or subcutaneous (1-10 mg/kg s.c.) injection of HTMT (H(1) receptor agonist) elicited a dose-related hyperalgesia in the early and late phases. Conversely, intraperitoneal (20 and 30 mg/kg i.p.) injection of dexchlorpheniramine (H(1) receptor antagonist) was antinociceptive in both phases. At a dose ineffective per se, dexchlorpheniramine (10 mg/kg i.p.) antagonized the hyperalgesia induced by HTMT (40 mug/mouse i.c.v. or 10 mg/kg s.c.). Dimaprit (H(2) receptor agonist, 30 mg/kg i.p.) and ranitidine (H(2) receptor antagonist, 20 and 40 mg/kg i.p.) reduced the nociceptive responses in the early and late phases. No significant change in the antinociceptive activity was found following the combination of dimaprit (30 mg/kg i.p.) with ranitidine (10 mg/kg i.p.). The antinociceptive effect of dimaprit (30 mg/kg i.p.) was prevented by naloxone (5 mg/kg i.p.) in the early phase or by imetit (H(3) receptor agonist, 25 mg/kg i.p.) in both early and late phases. The histamine H(3) receptor agonist imetit was hyperalgesic following i.p. administration of 50 mg/kg. Imetit-induced hyperalgesia was completely prevented by treatment with a dose ineffective per se of thioperamide (H(3) receptor antagonist, 5 mg/kg i.p.). The results suggest that histamine H(1) and H(3) receptor activations increase sensitivity to nociceptive stimulus in the formalin test.

  6. Constitutive and ligand-induced nuclear localization of oxytocin receptor.

    PubMed

    Kinsey, Conan G; Bussolati, Gianni; Bosco, Martino; Kimura, Tadashi; Pizzorno, Marie C; Chernin, Mitchell I; Cassoni, Paola; Novak, Josef F

    2007-01-01

    Oxytocin receptor (OTR) is a membrane protein known to mediate oxytocin (OT) effects, in both normal and neoplastic cells. We report here that human osteosarcoma (U2OS, MG63, OS15 and SaOS2), breast cancer (MCF7), and primary human fibroblastic cells (HFF) all exhibit OTR not only on the cell membrane, but also in the various nuclear compartments including the nucleolus. Both an OTR-GFP fusion protein and the native OTR appear to be localized to the nucleus as detected by transfection and/or confocal immunofluorescence, respectively. Treatment with oxytocin causes internalization of OTR and the resulting vesicles accumulate in the vicinity of the nucleus and some of the perinuclear OTR enters the nucleus. Western blots indicate that OTR in the nucleus and on the plasma membrane are likely to be the same biochemical and immunological entities. It appears that OTR is first visible in the nucleoli and subsequently disperses within the nucleus into 4-20 spots while some of the OTR diffuses throughout the nucleoplasm. The behaviour and kinetics of OTR-GFP and OTR are different, indicating interference by GFP in both OTR entrance into the nucleus and subsequent relocalization of OTR within the nucleus. There are important differences among the tested cells, such as the requirement of a ligand for transfer of OTR in nuclei. A constitutive internalization of OTR was found only in osteosarcoma cells, while the nuclear localization in all other tested cells was dependent on ligand binding. The amount of OTR-positive material within and in the vicinity of the nucleus increased following a treatment with oxytocin in both constitutive and ligand-dependent type of cells. The evidence of OTR compartmentalization at the cell nucleus (either ligand-dependent or constitutive) in different cell types suggests still unknown biological functions of this protein or its ligand and adds this G-protein-coupled receptor to other heptahelical receptors displaying this atypical and unexpected

  7. Nitric oxide content and apoptosis rate in steroid-induced avascular necrosis of the femoral head

    PubMed Central

    BAI, RUI; LIU, WANLIN; ZHAO, AIQING; ZHAO, ZHENGQUN; JIANG, DIANMING

    2015-01-01

    The aim of the present study was to explore the effect on nitric oxide (NO) content and osteocyte apoptosis of steroid-induced avascular necrosis of the femoral head (SANFH) in an animal model of SANFH. A total of 40 Japanese white rabbits, 5 months of age and weighing 2.5±0.5 kg, were randomly divided into groups A (hormone + endotoxin group), B (endotoxin + normal saline group), C (normal saline + hormone group) and D (control group). Following the establishment of the model, a blood sample was taken from the heart of each animal and centrifuged; the levels of NO in the serum were detected. The bilateral femoral heads were conventionally dissected, fixed, decalcified and stained with hematoxylin and eosin. Subsequently, the empty bone lacunae were counted under an optical microscope. Changes in osteocyte morphology were observed using electron microscopy and osteocyte apoptosis was detected with a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The percentage of empty bone lacunae in group A was significantly higher compared with that in groups B, C and D (P<0.01); however, there was no significant difference in percentage among groups B, C and D. The NO content in group A was significantly higher compared with that in groups B, C and D (P<0.01); however, there was no significant difference in NO content among groups B, C and D. The osteocyte apoptosis index in group A was significantly higher compared with that in the other groups (P<0.01); there was no significant difference among groups B, C and D. NO content was positively correlated with osteocyte apoptosis index (r=0.707). Thus, the present study found that NO content and the osteocyte apoptosis index were increased in SANFH, and that they play an important role in SANFH. The content of NO was positively correlated with the osteocyte apoptosis index, indicating that NO induces apoptosis. PMID:26622359

  8. Development and Validation of a High-Content Screening Assay to Identify Inhibitors of Cytoplasmic Dynein-Mediated Transport of Glucocorticoid Receptor to the Nucleus

    PubMed Central

    Shinde, Sunita N.; Hua, Yun; Shun, Tong Ying; Lazo, John S.; Day, Billy W.

    2012-01-01

    Abstract Rapid ligand-induced trafficking of glucocorticoid nuclear hormone receptor (GR) from the cytoplasm to the nucleus is an extensively studied model for intracellular retrograde cargo transport employed in constructive morphogenesis and many other cellular functions. Unfortunately, potent and selective small-molecule disruptors of this process are lacking, which has restricted pharmacological investigations. We describe here the development and validation of a 384-well high-content screening (HCS) assay to identify inhibitors of the rapid ligand-induced retrograde translocation of cytoplasmic glucocorticoid nuclear hormone receptor green fluorescent fusion protein (GR-GFP) into the nuclei of 3617.4 mouse mammary adenocarcinoma cells. We selected 3617.4 cells, because they express GR-GFP under the control of a tetracycline (Tet)-repressible promoter and are exceptionally amenable to image acquisition and analysis procedures. Initially, we investigated the time-dependent expression of GR-GFP in 3617.4 cells under Tet-on and Tet-off control to determine the optimal conditions to measure dexamethasone (Dex)-induced GR-GFP nuclear translocation on the ArrayScan-VTI automated imaging platform. We then miniaturized the assay into a 384-well format and validated the performance of the GR-GFP nuclear translocation HCS assay in our 3-day assay signal window and dimethylsulfoxide validation tests. The molecular chaperone heat shock protein 90 (Hsp90) plays an essential role in the regulation of GR steroid binding affinity and ligand-induced retrograde trafficking to the nucleus. We verified that the GR-GFP HCS assay captured the concentration-dependent inhibition of GR-GFP nuclear translocation by 17-AAG, a benzoquinone ansamycin that selectively blocks the binding and hydrolysis of ATP by Hsp90. We screened the 1280 compound library of pharmacologically active compounds set in the Dex-induced GR-GFP nuclear translocation assay and used the multi-parameter HCS data to

  9. Nigella sativa Relieves the Altered Insulin Receptor Signaling in Streptozotocin-Induced Diabetic Rats Fed with a High-Fat Diet

    PubMed Central

    El-Zeftawy, Marwa; Taha, Nabil; Mandour, Abdel Wahab

    2016-01-01

    The black cumin (Nigella sativa) “NS” or the black seeds have many pharmacological activities such as antioxidant, anticarcinogenic, antihypertensive, and antidiabetic properties. In this work, streptozotocin-induced diabetic rats fed with a high-fat diet were treated daily with NS oil (NSO) in order to study the effect on the blood glucose, lipid profile, oxidative stress parameters, and the gene expression of some insulin receptor-induced signaling molecules. This treatment was combined also with some drugs (metformin and glimepiride) and the insulin receptor inhibitor I-OMe-AG538. The administration of NSO significantly induced the gene expression of insulin receptor compared to rats that did not receive NSO. Also, it upregulated the expression of insulin-like growth factor-1 and phosphoinositide-3 kinase, whereas the expression of ADAM-17 was downregulated. The expression of ADAM-17 is corroborated by the analysis of TIMP-3 content. In addition, the NSO significantly reduced blood glucose level, components of the lipid profile, oxidative stress parameters, serum insulin/insulin receptor ratio, and the tumor necrosis factor-α, confirming that NSO has an antidiabetic activity. Thus, the daily NSO treatment in our rat model indicates that NSO has a potential in the management of diabetes as well as improvement of insulin-induced signaling. PMID:27579151

  10. Involvement of cyclooxygenase-1, prostaglandin E2 and EP1 receptors in acid-induced HCO3- secretion in stomach.

    PubMed

    Takeuchi, K; Aihara, E; Sasaki, Y; Nomura, Y; Ise, F

    2006-12-01

    We investigated the cyclooxygenase (COX) isoforms as well as prostaglandin E receptor EP subtypes responsible for acid-induced gastric HCO(3)(-) secretion in rats and EP receptor-knockout (-/-) mice. Under urethane anesthesia, a chambered stomach (in the presence of omeprazole) was perfused with saline, and HCO(3)(-) secretion was measured at pH 7.0 using a pH-stat method and by adding 2 mM HCl. Mucosal acidification was achieved by exposing the stomach for 10 min to 50 or 100 mM HCl. Acidification of the mucosa increased the secretion of HCO(3)(-) in the stomach of both rats and WT mice, in an indomethacin-inhibitable manner. The acid-induced gastric HCO(3)(-) secretion was inhibited by prior administration of indomethacin and SC-560 but not rofecoxib in rats and mice. Acidification increased the PGE(2) content of the rat stomach, and this response was significantly attenuated by indomethacin and SC-560 but not rofecoxib. This response was also attenuated by ONO-8711 (EP1 antagonist) but not AE3-208 (EP4 antagonist) in rats and disappeared in EP1 (-/-) but not EP3 (-/-) mice. PGE(2) increased gastric HCO(3)(-) secretion in both rats and WT mice, and this action was inhibited by ONO-8711 and disappeared in EP1 (-/-) but not EP3 (-/-) mice. These results support a mediator role for endogenous PGs in the gastric response induced by mucosal acidification and clearly indicate that the enzyme responsible for production of PGs in this process is COX-1. They further show that the presence of EP1 receptors is essential for the increase in the secretion of HCO(3)(-) in response to mucosal acidification in the stomach.

  11. Decreased brain histamine content in hypocretin/orexin receptor-2 mutated narcoleptic dogs.

    PubMed

    Nishino, S; Fujiki, N; Ripley, B; Sakurai, E; Kato, M; Watanabe, T; Mignot, E; Yanai, K

    2001-11-09

    A growing amount of evidence suggests that a deficiency in hypocretin/orexin neurotransmission is critically involved in animal and human forms of narcolepsy. Since hypocretin-containing neurons innervate and excite histaminergic tuberomammillary neurons, altered histaminergic neurotransmission may also be involved in narcolepsy. We found a significant decrease in histamine content in the cortex and thalamus, two structures important for histamine-mediated cortical arousal, in Hcrtr-2 mutated narcoleptic Dobermans. In contrast, dopamine and norepinephrine contents in these structures were elevated in narcoleptic animals, a finding consistent with our hypothesis of altered catecholaminergic transmission in these animals. Considering the fact that histamine promotes wakefulness, decreases in histaminergic neurotransmission may also account for the sleep abnormalities in hypocretin-deficient narcolepsy.

  12. Regulation of the Structurally Dynamic N-terminal Domain of Progesterone Receptor by Protein-induced Folding*

    PubMed Central

    Kumar, Raj; Moure, Carmen M.; Khan, Shagufta H.; Callaway, Celetta; Grimm, Sandra L.; Goswami, Devrishi; Griffin, Patrick R.; Edwards, Dean P.

    2013-01-01

    The N-terminal domain (NTD) of steroid receptors harbors a transcriptional activation function (AF1) that is composed of an intrinsically disordered polypeptide. We examined the interaction of the TATA-binding protein (TBP) with the NTD of the progesterone receptor (PR) and its ability to regulate AF1 activity through coupled folding and binding. As assessed by solution phase biophysical methods, the isolated NTD of PR contains a large content of random coil, and it is capable of adopting secondary α-helical structure and more stable tertiary folding either in the presence of the natural osmolyte trimethylamine-N-oxide or through a direct interaction with TBP. Hydrogen-deuterium exchange coupled with mass spectrometry confirmed the highly dynamic intrinsically disordered property of the NTD within the context of full-length PR. Deletion mapping and point mutagenesis defined a region of the NTD (amino acids 350–428) required for structural folding in response to TBP interaction. Overexpression of TBP in cells enhanced transcriptional activity mediated by the PR NTD, and deletion mutations showed that a region (amino acids 327–428), similar to that required for TBP-induced folding, was required for functional response. TBP also increased steroid receptor co-activator 1 (SRC-1) interaction with the PR NTD and cooperated with SRC-1 to stimulate NTD-dependent transcriptional activity. These data suggest that TBP can mediate structural reorganization of the NTD to facilitate the binding of co-activators required for maximal transcriptional activation. PMID:23995840

  13. Dopamine receptor alterations in female rats with diet-induced decreased brain docosahexaenoic acid (DHA): interactions with reproductive status

    PubMed Central

    Davis, Paul F.; Ozias, Marlies K.; Carlson, Susan E.; Reed, Gregory A.; Winter, Michelle K.; McCarson, Kenneth E.; Levant, Beth

    2010-01-01

    Decreased tissue levels of n-3 (omega-3) fatty acids, particularly docosahexaenoic acid (DHA), are implicated in the etiologies of non-puerperal and postpartum depression. This study examined the effects of a diet-induced loss of brain DHA content and concurrent reproductive status on dopaminergic parameters in adult female Long–Evans rats. An α-linolenic acid-deficient diet and breeding protocols were used to produce virgin and parous female rats with cortical phospholipid DHA levels 20–22% lower than those fed a control diet containing adequate α-linolenic acid. Decreased brain DHA produced a significant main effect of decreased density of ventral striatal D2-like receptors. Virgin females with decreased DHA also exhibited higher density of D1-like receptors in the caudate nucleus than virgin females with normal DHA. These receptor alterations are similar to those found in several rodent models of depression, and are consistent with the proposed hypodopaminergic basis for anhedonia and motivational deficits in depression. PMID:20670471

  14. Ameliorative effect of a hippocampal metabotropic glutamate- receptor agonist on histamine H1 receptor antagonist-induced memory deficit in rats.

    PubMed

    Masuoka, Takayoshi; Mikami, Azusa; Kamei, Chiaki

    2010-01-01

    This study was performed to investigate the ameliorative effects of metabotropic glutamate (mGlu)-receptor agonists on histamine H(1) receptor antagonist-induced spatial memory deficit and the decrease in hippocampal theta activity in rats. Intraperitoneal injection of pyrilamine (35 mg/kg) resulted in impaired reference and working memory in the radial maze task and decreased hippocampal theta amplitude and power. The working memory deficit and decreased hippocampal theta power induced by pyrilamine were ameliorated by intrahippocampal injection of (RS)-3,5-dihydroxyphenylglycine (DHPG) (1 and 10 microg/side), a group I mGlu-receptor agonist; however, intrahippocampal injection of (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC), a group II mGlu-receptor agonist, and L-(+)-2-amino-4-phosphonobutyric acid (L-AP4), a group III mGlu-receptor agonist, showed no significant effect on the pyrilamine-induced memory deficit and decreased hippocampal theta activity. These results indicate that the activation of hippocampal group I mGlu receptors, but not group II and III mGlu receptors, improve the histamine H(1) receptor antagonist-induced working memory deficit and decreased hippocampal theta activity.

  15. 5-HT7 receptor activation attenuates thermal hyperalgesia in streptozocin-induced diabetic mice.

    PubMed

    Ulugol, Ahmet; Oltulu, Cagatay; Gunduz, Ozgur; Citak, Cihad; Carrara, Roberto; Shaqaqi, Mohammad Reza; Sanchez, Alicia Mansilla; Dogrul, Ahmet

    2012-08-01

    The role of 5-HT7 receptors in the nociceptive processing received most attention during the last few years. The involvement of 5-HT₇ receptors in nerve injury-induced neuropathic pain states have been reported only recently; however, there are no reports on its contribution in diabetic neuropathic pain. We therefore planned to investigate the effect of 5-HT₇ receptor activation on the changes of nociceptive threshold in diabetic mice. Diabetes was induced by a single intraperitoneal injection of streptozocin (150 mg/kg, i.p.). The nociceptive responses in normal and diabetic animals were tested in the hot-plate and tail-flick assays. Both hot-plate and tail-flick latencies significantly shortened at 1-3/4 weeks (thermal hyperalgesia) and prolonged at 6-7 weeks (thermal hypoalgesia) after streptozocin administration. At the dose of 10 mg/kg, systemic injections of AS-19, a selective 5-HT₇ receptor agonist, reduced thermal hyperalgesia at early stage of diabetes, but did not influence thermal hypoalgesia at late stage. Co-administration of SB-258719, a selective 5-HT₇ receptor antagonist, at a dose that had no effect on its own (10 mg/kg), reversed the anti-hyperalgesic effect of AS-19. Our results indicate that systemic administration of 5-HT₇ receptor agonists may have clinical utility in treating diabetic neuropathic pain.

  16. Phorbol ester induced phosphorylation of the estrogen receptor in intact MCF-7 human breast cancer cells

    SciTech Connect

    Knabbe, C.; Lippman, M.E.; Greene, G.L.; Dickson, R.B.

    1986-05-01

    Recent studies with a variety of cellular receptors have shown that phorbol ester induced phosphorylation modulates ligand binding and function. In this study the authors present direct evidence that the estrogen receptor in MCF-7 human breast cancer cells is a phosphoprotein whose phosphorylation state can be enhanced specifically by phorbol-12-myristate-13-acetate (PMA). Cells were cultured to 6h in the presence of (/sup 32/P)-orthophosphate. Whole cell extracts were immunoprecipitated with a monoclonal antibody (D58) against the estrogen receptor and subjected to SDS-polyacrylamide electrophoresis. Autoradiography showed a specific band in the region of 60-62 kDa which was significantly increased in preparations from PMA treated cells. Phospho-amino acid analysis demonstrated specific phosphorylation of serine and threonine residues. Cholera toxin or forskolin did not change the phosphorylation state of this protein. In a parallel binding analysis PMA led to a rapid decrease of estrogen binding sites. The estrogen induction of both progesterone receptors and growth in semisolid medium was blocked by PMA, whereas the estrogen induction of the 8kDa protein corresponding to the ps2 gene product and of the 52 kDa protein was not affected. In conclusion, phorbol esters can induce phosphorylation of the estrogen receptor. This process may be associated with the inactivation of certain receptor functions.

  17. Wounding induces changes in cytokinin and auxin content in potato tuber, but does not induce formation of gibberellins.

    PubMed

    Lulai, Edward C; Suttle, Jeffrey C; Olson, Linda L; Neubauer, Jonathan D; Campbell, Larry G; Campbell, Michael A

    2016-02-01

    Cytokinin, auxin and gibberellin contents in resting and wound-responding potato tubers have not been fully determined and coordinated with wound-healing processes. Using a well-defined wound-healing model system, hormone content and expression of genes associated with hormone turnover were determined in tubers following wounding. Changes in hormone content were coordinated with: (I) formation and completion of the wound closing layer (0-5/6 days), and (II) initiation of phellogen and wound periderm formation (∼ 7 days). Quantifiable amounts of biologically active cytokinins (Z, DZ and IP) were not detected in resting or wound-responding tubers. However, the precursor IPA and catabolic product c-ZOG were found in small amounts in resting and wound-responding tubers. Wound-induced activation of cytokinin biosynthesis was suggested by an increase in t-ZR and c-ZR content at 0.5 days and large increases in IPA and c-ZR content by 3 days and throughout 7 days after wounding suggesting roles in II, but little or no role in I. Expression of key genes involved in cytokinin metabolism followed similar profiles with transcripts decreasing through 3 days and then increasing at 5-7 days after wounding. Both free IAA and IAA-Asp were present in resting tubers. While IAA-Asp was no longer present by 3 days after wounding, IAA content nearly doubled by 5 days and was more than 4-fold greater at 7 days compared to that in resting tuber (0 day) suggesting roles in II, but little or no role in I. Gibberellins were not present in quantifiable amounts in resting or wound-responding tubers. These results suggest that bio-active cytokinins are wound-induced, but their residency is temporal and highly regulated. The transient presence of active cytokinins and corresponding increases in IAA content strongly suggest their involvement in the regulation of wound periderm development. The absence of gibberellins indicates that they are not a regulatory component of wound-healing processes.

  18. Progesterone modulates the LPS-induced nitric oxide production by a progesterone-receptor independent mechanism.

    PubMed

    Wolfson, Manuel Luis; Schander, Julieta Aylen; Bariani, María Victoria; Correa, Fernando; Franchi, Ana María

    2015-12-15

    Genital tract infections caused by Gram-negative bacteria induce miscarriage and are one of the most common complications of human pregnancy. LPS administration to 7-day pregnant mice induces embryo resorption after 24h, with nitric oxide playing a fundamental role in this process. We have previously shown that progesterone exerts protective effects on the embryo by modulating the inflammatory reaction triggered by LPS. Here we sought to investigate whether the in vivo administration of progesterone modulated the LPS-induced nitric oxide production from peripheral blood mononuclear cells from pregnant and non-pregnant mice. We found that progesterone downregulated LPS-induced nitric oxide production by a progesterone receptor-independent mechanism. Moreover, our results suggest a possible participation of glucocorticoid receptors in at least some of the anti-inflammatory effects of progesterone.

  19. NOP Receptor Mediates Anti-analgesia Induced by Agonist-Antagonist Opioids

    PubMed Central

    Gear, Robert W.; Bogen, Oliver; Ferrari, Luiz F.; Green, Paul G.; Levine, Jon D.

    2014-01-01

    Clinical studies have shown that agonist-antagonist opioid analgesics that produce their analgesic effect via action on the kappa-opioid receptor, produce a delayed-onset anti-analgesia in men but not women, an effect blocked by co-administration of a low dose of naloxone. We now report the same time-dependent anti-analgesia and its underlying mechanism in an animal model. Using the Randall-Selitto paw-withdrawal assay in male rats, we found that nalbuphine, pentazocine, and butorphanol each produced analgesia during the first hour followed by anti-analgesia starting at ~90 minutes after administration in males but not females, closely mimicking its clinical effects. As observed in humans, co-administration of nalbuphine with naloxone in a dose ratio of 12.5:1 blocked anti-analgesia but not analgesia. Administration of the highly selective kappa-opioid receptor agonist U69,593 produced analgesia without subsequent anti-analgesia, and confirmed by the failure of the selective kappa antagonist nor-binaltorphimine to block nalbuphine-induced anti-analgesia, indicating that anti-analgesia is not mediated by kappa-opioid receptors. We therefore tested the role of other receptors in nalbuphine anti-analgesia. Nociceptin/orphanin FQ (NOP) and sigma-1 and sigma-2 receptors were chosen on the basis of their known anti-analgesic effects and receptor binding studies. The selective NOP receptor antagonists, JTC801, and J113397, but not the sigma receptor antagonist, BD 1047, antagonized nalbuphine anti-analgesia. Furthermore, the NOP receptor agonist NNC 63-0532 produced anti-analgesia with the same delay in onset observed with the three agonist-antagonists, but without producing preceding analgesia and this anti-analgesia was also blocked by naloxone. These results strongly support the suggestion that clinically used agonist-antagonists act at the NOP receptor to produce anti-analgesia. PMID:24188792

  20. Ligand-induced EGF Receptor Oligomerization Is Kinase-dependent and Enhances Internalization*

    PubMed Central

    Hofman, Erik G.; Bader, Arjen N.; Voortman, Jarno; van den Heuvel, Dave J.; Sigismund, Sara; Verkleij, Arie J.; Gerritsen, Hans C.; van Bergen en Henegouwen, Paul M. P.

    2010-01-01

    The current activation model of the EGF receptor (EGFR) predicts that binding of EGF results in dimerization and oligomerization of the EGFR, leading to the allosteric activation of the intracellular tyrosine kinase. Little is known about the regulatory mechanism of receptor oligomerization. In this study, we have employed FRET between identical fluorophores (homo-FRET) to monitor the dimerization and oligomerization state of the EGFR before and after receptor activation. Our data show that, in the absence of ligand, ∼40% of the EGFR molecules were present as inactive dimers or predimers. The monomer/predimer ratio was not affected by deletion of the intracellular domain. Ligand binding induced the formation of receptor oligomers, which were found in both the plasma membrane and intracellular structures. Ligand-induced oligomerization required tyrosine kinase activity and nine different tyrosine kinase substrate residues. This indicates that the binding of signaling molecules to activated EGFRs results in EGFR oligomerization. Induction of EGFR predimers or pre-oligomers using the EGFR fused to the FK506-binding protein did not affect signaling but was found to enhance EGF-induced receptor internalization. Our data show that EGFR oligomerization is the result of EGFR signaling and enhances EGFR internalization. PMID:20940297

  1. Nitric oxide and NK(1)-tachykinin receptors in cyclophosphamide-induced cystitis, in rats.

    PubMed

    Alfieri, A B; Cubeddu, L X

    2000-11-01

    The present study was conducted to investigate the role of NK(1) receptors and of nitric oxide (NO) on the pathogenesis of cyclophosphamide-induced cystitis, in rats. This bladder toxicity was characterized by marked increases in protein plasma extravasation, urothelial damage, edema, white blood cell infiltrates, and vascular congestion. These changes were associated with appearance of Ca(2+)-independent NO-synthase (NOS) activity [characteristic of inducible NOS (iNOS)] in the bladder and with increases in urinary NO metabolites. GR205171, a selective NK(1) antagonist (10-20 mg/kg, i.p.) reduced cyclophosphamide-induced increases in protein plasma extravasation and in the urinary excretion of NO metabolites. N(G)-Nitro-L-arginine (L-NNA) (10 mg/kg, i.p.), a NOS inhibitor, reduced basal and cyclophosphamide-induced increases in NO metabolites and protected against cyclophosphamide-induced protein plasma extravasation. GR205171 had no effect, whereas L-NNA reduced basal NO metabolite excretion. Combined treatment with the NK(1) antagonist and the NO-synthesis inhibitor produced comparable reduction in protein plasma extravasation than that achieved with each drug given separately. Combined drug treatment ameliorated cyclophosphamideinduced urothelial damage, and the extent of edema, vascular congestion, and white blood cell infiltrates in the bladder. In summary, NK(1) receptors and iNOS play a role in NO formation and on cyclophosphamide-induced cystitis. Activation of NK(1) receptors mainly acts through the formation of NO. It is proposed that cyclophosphamide and/or its metabolites would stimulate primary afferent capsaicin-sensitive fibers in the bladder, releasing neuropeptides, which would activate NK(1) receptors. However, additional mechanisms are involved, because neither the NK(1) receptor antagonist nor the NO synthesis inhibitor, either alone or in combination, were able to completely prevent the toxicity.

  2. Blockade of 5-HT2 Receptor Selectively Prevents MDMA-Induced Verbal Memory Impairment

    PubMed Central

    van Wel, J H P; Kuypers, K P C; Theunissen, E L; Bosker, W M; Bakker, K; Ramaekers, J G

    2011-01-01

    3,4-Methylenedioxymethamphetamine (MDMA) or ‘ecstasy' has been associated with memory deficits during abstinence and intoxication. The human neuropharmacology of MDMA-induced memory impairment is unknown. This study investigated the role of 5-HT2A and 5-HT1A receptors in MDMA-induced memory impairment. Ketanserin is a 5-HT2A receptor blocker and pindolol a 5-HT1A receptor blocker. It was hypothesized that pretreatment with ketanserin and pindolol would protect against MDMA-induced memory impairment. Subjects (N=17) participated in a double-blind, placebo-controlled, within-subject design involving six experimental conditions consisting of pretreatment (T1) and treatment (T2). T1 preceded T2 by 30 min. T1–T2 combinations were: placebo–placebo, pindolol 20 mg–placebo, ketanserin 50 mg–placebo, placebo–MDMA 75 mg, pindolol 20 mg–MDMA 75 mg, and ketanserin 50 mg–MDMA 75 mg. Memory function was assessed at Tmax of MDMA by means of a word-learning task (WLT), a spatial memory task and a prospective memory task. MDMA significantly impaired performance in all memory tasks. Pretreatment with a 5-HT2A receptor blocker selectively interacted with subsequent MDMA treatment and prevented MDMA-induced impairment in the WLT, but not in the spatial and prospective memory task. Pretreatment with a 5-HT1A blocker did not affect MDMA-induced memory impairment in any of the tasks. Together, the results demonstrate that MDMA-induced impairment of verbal memory as measured in the WLT is mediated by 5-HT2A receptor stimulation. PMID:21562484

  3. Phencyclidine-induced social withdrawal results from deficient stimulation of cannabinoid CB₁ receptors: implications for schizophrenia.

    PubMed

    Seillier, Alexandre; Martinez, Alex A; Giuffrida, Andrea

    2013-08-01

    The neuronal mechanisms underlying social withdrawal, one of the core negative symptoms of schizophrenia, are not well understood. Recent studies suggest an involvement of the endocannabinoid system in the pathophysiology of schizophrenia and, in particular, of negative symptoms. We used biochemical, pharmacological, and behavioral approaches to investigate the role played by the endocannabinoid system in social withdrawal induced by sub-chronic administration of phencyclidine (PCP). Pharmacological enhancement of endocannabinoid levels via systemic administration of URB597, an inhibitor of endocannabinoid degradation, reversed social withdrawal in PCP-treated rats via stimulation of CB1 receptors, but reduced social interaction in control animals through activation of a cannabinoid/vanilloid-sensitive receptor. In addition, the potent CB agonist CP55,940 reversed PCP-induced social withdrawal in a CB₁-dependent manner, whereas pharmacological blockade of CB₁ receptors by either AM251 or SR141716 reduced the time spent in social interaction in control animals. PCP-induced social withdrawal was accompanied by a decrease of anandamide (AEA) levels in the amygdala and prefrontal cortex, and these deficits were reversed by URB597. As CB₁ receptors are predominantly expressed on GABAergic interneurons containing the anxiogenic peptide cholecystokinin (CCK), we also examined whether the PCP-induced social withdrawal resulted from deficient CB₁-mediated modulation of CCK transmission. The selective CCK2 antagonist LY225910 blocked both PCP- and AM251-induced social withdrawal, but not URB597 effect in control rats. Taken together, these findings indicate that AEA-mediated activation of CB₁ receptors is crucial for social interaction, and that PCP-induced social withdrawal results from deficient endocannabinoid transmission.

  4. TNF-α receptor antagonist attenuates isoflurane-induced cognitive impairment in aged rats

    PubMed Central

    YANG, NENGLI; LIANG, YAFENG; YANG, PEI; WANG, WEIJIAN; ZHANG, XUEZHENG; WANG, JUNLU

    2016-01-01

    Postoperative cognitive dysfunction (POCD), a common clinical in aged patients, is characterized by deficits in cognitive functions in patients following anesthesia and surgery. It has been demonstrated that isoflurane may lead to cognitive impairment in aged rats; however, effective clinical interventions for preventing this disorder are limited. Tumor necrosis factor (TNF)-α has been suggested to be involved in neuroinflammation as well as the development of POCD. Accordingly, the present study aimed to investigate whether TNF-α signaling is involved in the isoflurane-induced cognitive impairment in aged rats, and whether TNF-α receptor antagonist are able to attenuate isoflurane-induced cognitive impairment in aged rats. A population of 20-month-old rats were administered TNF-α receptor antagonist R-7050 or an equal volume of saline by intraperitoneal injection 12 h prior to exposure to isoflurane to model cognitive impairment following anesthesia in old patients. Then the rats were exposed to 1.3% isoflurane for 4 h. In the control group, rats showed impaired cognitive functions evaluated by Morris water maze assay after isoflurane exposure. Furthermore, isoflurane exposure induced marked upregulation of proinflammatory cytokines, including interleukin (IL)-1β, TNF-α, IL-6 and IL-8 in the hippocampus tissue. In the experimental group, intracisternal administration of TNF-α receptor antagonist R-7050 significantly attenuated isoflurane-induced cognitive impairment and upregulation of proinflammatory cytokines. Further investigation revealed that intracisternal administration of TNF-α receptor antagonist R-7050 notably suppressed isoflurane-induced activation of NF-κB and MAPK signaling. Collectively, the present results suggest that TNF-α receptor antagonist may serve as a potential agent for the prevention of anesthesia-induced cognitive decline in aged patients. PMID:27347079

  5. D2 receptor block abolishes θ burst stimulation-induced neuroplasticity in the human motor cortex.

    PubMed

    Monte-Silva, Katia; Ruge, Diane; Teo, James T; Paulus, Walter; Rothwell, John C; Nitsche, Michael A

    2011-09-01

    Dopamine (DA) is a neurotransmitter with an important influence on learning and memory, which is thought to be due to its modulatory effect on plasticity at central synapses, which in turn depends on activation of D1 and D2 receptors. Methods of brain stimulation (transcranial direct current stimulation, tDCS; paired associative stimulation, PAS) lead to after-effects on cortical excitability that are thought to resemble long-term potentization (LTP)/long-term depression (LTD) in reduced preparations. In a previous study we found that block of D2 receptors abolished plasticity induced by tDCS but had no effect on the facilitatory plasticity induced by PAS. We postulated that the different effect of D2 receptor block on tDCS- and PAS-induced plasticity may be due to the different focality and associativity of the stimulation techniques. However, alternative explanations for this difference could not be ruled out. tDCS also differs from PAS in other aspects, as tDCS induces plasticity by subthreshold neuronal activation, modulating spontaneous activity, whereas PAS induces plasticity via phasic suprathreshold stimulation. The present study in 12 volunteers examined effects of D2 receptor blockade (sulpiride (SULP) 400 mg), on the LTP/LTD-like effects of theta burst transcranial magnetic stimulation (TBS), which has less restricted effects on cortical synapses than that of PAS, and does not induce associative plasticity, similar to tDCS, but on the other hand induces cortical excitability shifts by suprathreshold (rhythmic) activation of cortical neurons similarly to PAS. Administration of SULP blocked both the excitatory and inhibitory effects of intermittent (iTBS) and continuous TBS (cTBS), respectively. As the reduced response to TBS following SULP resembles its effect on tDCS, the results support an effect of DA on plasticity, which might be related to the focality and associativity of the plasticity induced.

  6. A constitutively active dioxin/aryl hydrocarbon receptor induces stomach tumors

    NASA Astrophysics Data System (ADS)

    Andersson, Patrik; McGuire, Jacqueline; Rubio, Carlos; Gradin, Katarina; Whitelaw, Murray L.; Pettersson, Sven; Hanberg, Annika; Poellinger, Lorenz

    2002-07-01

    The dioxin/aryl hydrocarbon receptor (AhR) functions as a ligand-activated transcription factor regulating transcription of a battery of genes encoding xenobiotic metabolizing enzymes. Known receptor ligands are environmental pollutants including polycyclic aromatic hydrocarbons and polychlorinated dioxins. Loss-of-function (gene-disruption) studies in mice have demonstrated that the AhR is involved in toxic effects of dioxins but have not yielded unequivocal results concerning the physiological function of the receptor. Gain-of-function studies therefore were performed to unravel the biological functions of the AhR. A constitutively active AhR expressed in transgenic mice reduced the life span of the mice and induced tumors in the glandular part of the stomach, demonstrating the oncogenic potential of the AhR and implicating the receptor in regulation of cell proliferation.

  7. A constitutively active dioxin/aryl hydrocarbon receptor induces stomach tumors

    PubMed Central

    Andersson, Patrik; McGuire, Jacqueline; Rubio, Carlos; Gradin, Katarina; Whitelaw, Murray L.; Pettersson, Sven; Hanberg, Annika; Poellinger, Lorenz

    2002-01-01

    The dioxin/aryl hydrocarbon receptor (AhR) functions as a ligand-activated transcription factor regulating transcription of a battery of genes encoding xenobiotic metabolizing enzymes. Known receptor ligands are environmental pollutants including polycyclic aromatic hydrocarbons and polychlorinated dioxins. Loss-of-function (gene-disruption) studies in mice have demonstrated that the AhR is involved in toxic effects of dioxins but have not yielded unequivocal results concerning the physiological function of the receptor. Gain-of-function studies therefore were performed to unravel the biological functions of the AhR. A constitutively active AhR expressed in transgenic mice reduced the life span of the mice and induced tumors in the glandular part of the stomach, demonstrating the oncogenic potential of the AhR and implicating the receptor in regulation of cell proliferation. PMID:12107286

  8. Multiple CNS nicotinic receptors mediate L-dopa-induced dyskinesias: studies with parkinsonian nicotinic receptor knockout mice.

    PubMed

    Quik, Maryka; Campos, Carla; Grady, Sharon R

    2013-10-15

    Accumulating evidence supports the idea that drugs acting at nicotinic acetylcholine receptors (nAChRs) may be beneficial for Parkinson's disease, a neurodegenerative movement disorder characterized by a loss of nigrostriatal dopaminergic neurons. Nicotine administration to parkinsonian animals protects against nigrostriatal damage. In addition, nicotine and nAChR drugs improve L-dopa-induced dyskinesias, a debilitating side effect of L-dopa therapy which remains the gold-standard treatment for Parkinson's disease. Nicotine exerts its antidyskinetic effect by interacting with multiple nAChRs. One approach to identify the subtypes specifically involved in L-dopa-induced dyskinesias is through the use of nAChR subunit null mutant mice. Previous work with β2 and α6 nAChR knockout mice has shown that α6β2* nAChRs were necessary for the development/maintenance of L-dopa-induced abnormal involuntary movements (AIMs). The present results in parkinsonian α4 nAChR knockout mice indicate that α4β2* nAChRs also play an essential role since nicotine did not reduce L-dopa-induced AIMs in such mice. Combined analyses of the data from α4 and α6 knockout mice suggest that the α6α4β2β3 subtype may be critical. In contrast to the studies with α4 and α6 knockout mice, nicotine treatment did reduce L-dopa-induced AIMs in parkinsonian α7 nAChR knockout mice. However, α7 nAChR subunit deletion alone increased baseline AIMs, suggesting that α7 receptors exert an inhibitory influence on L-dopa-induced AIMs. In conclusion, α6β2*, α4β2* and α7 nAChRs all modulate L-dopa-induced AIMs, although their mode of regulation varies. Thus drugs targeting one or multiple nAChRs may be optimal for reducing L-dopa-induced dyskinesias in Parkinson's disease.

  9. INTERACTION BETWEEN DELTA OPIOID RECEPTORS AND BENZODIAZEPINES IN CO2- INDUCED RESPIRATORY RESPONSES IN MICE

    PubMed Central

    Borkowski, Anne H.; Barnes, Dylan C.; Blanchette, Derek R.; Castellanos, F. Xavier; Klein, Donald F.; Wilson, Donald A.

    2011-01-01

    The false-suffocation hypothesis of panic disorder (Klein, 1993) suggested δ-opioid receptors as a possible source of the respiratory dysfunction manifested in panic attacks occurring in panic disorder (Preter and Klein, 2008). This study sought to determine if a lack of δ-opioid receptors in a mouse model affects respiratory response to elevated CO2, and whether the response is modulated by benzodiazepines, which are widely used to treat panic disorder. In a whole-body plethysmograph, respiratory responses to 5% CO2 were compared between δ-opioid receptor knockout mice and wild-type mice after saline, diazepam (1 mg/kg), and alprazolam (0.3 mg/kg) injection. The results show that lack of δ-opioid receptors does not affect normal response to elevated CO2, but does prevent benzodiazepines from modulating that response. Thus, in the presence of benzodiazepine agonists, respiratory responses to elevated CO2 were enhanced in δ-opioid receptor knockout mice compared to wild-type mice. This suggests an interplay between benzodiazepine receptors and δ-opioid receptors in regulating the respiratory effects of elevated CO2, which might be related to CO2 induced panic. PMID:21561601

  10. Liver X receptor β activation induces pyroptosis of human and murine colon cancer cells

    PubMed Central

    Derangère, V; Chevriaux, A; Courtaut, F; Bruchard, M; Berger, H; Chalmin, F; Causse, S Z; Limagne, E; Végran, F; Ladoire, S; Simon, B; Boireau, W; Hichami, A; Apetoh, L; Mignot, G; Ghiringhelli, F; Rébé, C

    2014-01-01

    Liver X receptors (LXRs) have been proposed to have some anticancer properties, through molecular mechanisms that remain elusive. Here we report for the first time that LXR ligands induce caspase-1-dependent cell death of colon cancer cells. Caspase-1 activation requires Nod-like-receptor pyrin domain containing 3 (NLRP3) inflammasome and ATP-mediated P2 × 7 receptor activation. Surprisingly, LXRβ is mainly located in the cytoplasm and has a non-genomic role by interacting with pannexin 1 leading to ATP secretion. Finally, LXR ligands have an antitumoral effect in a mouse colon cancer model, dependent on the presence of LXRβ, pannexin 1, NLRP3 and caspase-1 within the tumor cells. Our results demonstrate that LXRβ, through pannexin 1 interaction, can specifically induce caspase-1-dependent colon cancer cell death by pyroptosis. PMID:25124554

  11. Guanine nucleotide regulation of dopamine receptor agonist affinity states in rat estradiol-induced pituitary tumors

    SciTech Connect

    Di Paolo, T.; Falardeau, P.

    1987-08-31

    The authors have investigated dopamine (DA) receptor agonist high- and low-affinity states in female rate estradiol-induced prolactin (PRL)-secreting pituitary tumors and intact pituitary tissue. Estradiol treatment increased the anterior pituitary weight 9-fold and plasma prolactin levels 74-fold and these measures are correlated (R = 0.745, n = 73, p < 0.001). Competition for (/sup 3/H)-spiperone binding to the DA receptor by apomorphine was compared in normal and adenomatous pituitary tissue. The inhibition constants (Ki) and the proportions of the two apomorphine sites are unchanged in tumors compared to intact pituitary tissue. Guanosine 5'-(..beta..-..gamma..-imino)triphosphate (Gpp(NH)p) causes complete conversion of the high into low affinity dopaminergic agonist site in normal pituitary and in tumors. These results suggest that rats with primary estradiol-induced pituitary tumors have normal and functional DA receptors. 9 references, 2 tables.

  12. beta-Adrenergic and cholinergic receptors in hypertension-induced hypertrophy

    SciTech Connect

    Vatner, D.E.; Kirby, D.A.; Homcy, C.J.; Vatner, S.F.

    1985-05-01

    Perinephritic hypertension was produced in dogs by wrapping one kidney with silk and removing the contralateral kidney 1 week later. Mean arterial pressure rose from 104 +/- 3 to 156 +/- 11 mm Hg, while left ventricular free wall weight, normalized for body weight, was increased by 49%. Muscarinic, cholinergic receptor density measured with (/sup 3/H)-quinuclidinyl benzilate, fell in hypertensive left ventricles (181 +/- 19 fmol/mg, n = 6; p less than 0.01) as compared with that found in normal left ventricles (272 +/- 16 fmol/mg, n = 8), while receptor affinity was not changed. The beta-adrenergic receptor density, measured by binding studies with (/sup 3/H)-dihydroalprenolol, rose in the hypertensive left ventricles (108 +/- 10 fmol/mg, n = 7; p less than 0.01) as compared with that found in normal left ventricles (68.6 +/- 5.2 fmol/mg, n = 15), while beta-adrenergic receptor affinity decreased in the hypertensive left ventricles (10.4 +/- 1.2 nM) compared with that found in the normal left ventricles (5.0 +/- 0.7 nM). Plasma norepinephrine levels were similar in the two groups, but myocardial norepinephrine levels were depressed (p less than 0.05) in dogs with hypertension. Moderate left ventricular hypertrophy induced by long-term aortic banding in dogs resulted in elevations in beta-adrenergic receptor density (115 +/- 14 fmol/mg) and decreases in affinity (10.4 +/- 2.2 nM) similar to those observed in the dogs with left ventricular hypertrophy induced by hypertension. Thus, these results suggest that perinephritic hypertension in the dog induces divergent effects on cholinergic and beta-adrenergic receptor density. The increased beta-adrenergic receptor density and decreased affinity may be a characteristic of left ventricular hypertrophy rather than hypertension.

  13. Selective prostacyclin receptor agonism augments glucocorticoid-induced gene expression in human bronchial epithelial cells.

    PubMed

    Wilson, Sylvia M; Shen, Pamela; Rider, Christopher F; Traves, Suzanne L; Proud, David; Newton, Robert; Giembycz, Mark A

    2009-11-15

    Prostacyclin receptor (IP-receptor) agonists display anti-inflammatory and antiviral activity in cell-based assays and in preclinical models of asthma and chronic obstructive pulmonary disease. In this study, we have extended these observations by demonstrating that IP-receptor activation also can enhance the ability of glucocorticoids to induce genes with anti-inflammatory activity. BEAS-2B bronchial epithelial cells stably transfected with a glucocorticoid response element (GRE) luciferase reporter were activated in a concentration-dependent manner by the glucocorticoid dexamethasone. An IP-receptor agonist, taprostene, increased cAMP in these cells and augmented luciferase expression at all concentrations of dexamethasone examined. Analysis of the concentration-response relationship that described this effect showed that taprostene increased the magnitude of transcription without affecting the potency of dexamethasone and was, thus, steroid-sparing in this simple system. RO3244794, an IP-receptor antagonist, and oligonucleotides that selectively silenced the IP-receptor gene, PTGIR, abolished these effects of taprostene. Infection of BEAS-2B GRE reporter cells with an adenovirus vector encoding a highly selective inhibitor of cAMP-dependent protein kinase (PKA) also prevented taprostene from enhancing GRE-dependent transcription. In BEAS-2B cells and primary cultures of human airway epithelial cells, taprostene and dexamethasone interacted either additively or cooperatively in the expression of three glucocorticoid-inducible genes (GILZ, MKP-1, and p57(kip2)) that have anti-inflammatory potential. Collectively, these data show that IP-receptor agonists can augment the ability of glucocorticoids to induce anti-inflammatory genes in human airway epithelial cells by activating a cAMP/PKA-dependent mechanism. This observation may have clinical relevance in the treatment of airway inflammatory diseases that are either refractory or respond suboptimally to

  14. Emesis and Defecations Induced by the 5-Hydroxytryptamine (5-HT3) Receptor Anatagonist Zacopride in the Ferret

    DTIC Science & Technology

    1990-02-16

    and Defecations Induced by the 5 -Hydroxytryptamine ( 5 -HT 3) Receptor Antagonist Zacopride in the Ferret1 GREGORY L. KING Department of Physiology...benzamides and 5 -hydroxytryptamine ( 5 - Zacopride (4-amino-N-[ 1-azabicyclo(2.2.2)oct-3-yl]- 5 -chloro- HT:i) receptor antagonists are effective...prompted development of 5 - the dose-response properties of zacop -ide-induced emesis and HT, receptor antagonist antiemetics with limited gastric

  15. Extrasynaptic NMDA receptor-induced tau overexpression mediates neuronal death through suppressing survival signaling ERK phosphorylation

    PubMed Central

    Sun, Xu-Ying; Tuo, Qing-Zhang; Liuyang, Zhen-Yu; Xie, Ao-Ji; Feng, Xiao-Long; Yan, Xiong; Qiu, Mei; Li, Shen; Wang, Xiu-Lian; Cao, Fu-Yuan; Wang, Xiao-Chuan; Wang, Jian-Zhi; Liu, Rong

    2016-01-01

    Intracellular accumulation of the hyperphosphorylated tau is a pathological hallmark in the brain of Alzheimer disease. Activation of extrasynaptic NMDA receptors (E-NMDARs) induces excitatory toxicity that is involved in Alzheimer's neurodegeneration. However, the intrinsic link between E-NMDARs and the tau-induced neuronal damage remains elusive. In the present study, we showed in cultured primary cortical neurons that activation of E-NMDA receptors but not synaptic NMDA receptors dramatically increased tau mRNA and protein levels, with a simultaneous neuronal degeneration and decreased neuronal survival. Memantine, a selective antagonist of E-NMDARs, reversed E-NMDARs-induced tau overexpression. Activation of E-NMDARs in wild-type mouse brains resulted in neuron loss in hippocampus, whereas tau deletion in neuronal cultures and in the mouse brains rescued the E-NMDARs-induced neuronal death and degeneration. The E-NMDARs-induced tau overexpression was correlated with a reduced ERK phosphorylation, whereas the increased MEK activity, decreased binding and activity of ERK phosphatase to ERK, and increased ERK phosphorylation were observed in tau knockout mice. On the contrary, addition of tau proteins promoted ERK dephosphorylation in vitro. Taking together, these results indicate that tau overexpression mediates the excitatory toxicity induced by E-NMDAR activation through inhibiting ERK phosphorylation. PMID:27809304

  16. Methylenedioxymethamphetamine induces spontaneous tail-flicks in the rat via 5-HT1A receptors.

    PubMed

    Millan, M J; Colpaert, F C

    1991-02-07

    In rats lightly restrained in horizontal cylinders, (+/-)-3,4-methylenedioxymethamphetamine (MDMA) dose dependently (0.16-10.0 mg/kg, s.c.) elicited spontaneous tail-flicks; that is, tail-flicks in the absence of extraneous stimulation. In contrast, amphetamine over a similar dose-range was inactive. Selective inhibitors of 5-hydroxytryptamine (5-HT) uptake and carrier-mediated 5-HT release, paroxetine and citalopram, did not induce spontaneous tail-flicks themselves and blocked those induced by MDMA. In distinction, maprotiline and bupropion, selective inhibitors of noradrenaline and dopamine uptake, respectively, failed to modify the action of MDMA. Spontaneous tail-flicks elicited by MDMA were unaffected by the selective 5-HT3 receptor antagonists, ICS 205,930 and GR 38032F. They were attenuated by the mixed 5-HT1/5-HT2 receptor antagonist, methiotepin, the mixed 5-HT1A/5-HT1B receptor antagonist, (-)-alprenolol and the mixed 5-HT1A/5-HT2 receptor antagonist, spiperone, but not by the selective 5-HT1C/5-HT2 receptor antagonists, ritanserin, ICI 169,369 and ketanserin. The novel 5-HT1A receptor antagonists, BMY 7378 and NAN-190, each abolished MDMA-evoked spontaneous tail-flicks. Selective D1, D2, alpha 1, alpha 2, beta 1 and beta 2 antagonists had little influence upon induction of spontaneous tail-flicks by MDMA. These data indicate that MDMA evokes spontaneous tail-flicks in the rat via a release of 5-HT which acts at 5-HT1A receptors. Thus, 5-HT1A receptors appear to be involved in the acute functional actions of MDMA.

  17. Contribution of brain serotonin subtype 1B receptors in levodopa-induced motor complications.

    PubMed

    Morin, Nicolas; Morissette, Marc; Grégoire, Laurent; Rajput, Alex; Rajput, Ali H; Di Paolo, Thérèse

    2015-12-01

    L-DOPA-induced dyskinesias (LID) are abnormal involuntary movements limiting the chronic use of L-DOPA, the main pharmacological treatment of Parkinson's disease. Serotonin receptors are implicated in the development of LID and modulation of basal ganglia 5-HT1B receptors is a potential therapeutic alternative in Parkinson's disease. In the present study, we used receptor-binding autoradiography of the 5-HT1B-selective radioligand [3H]GR125743 to investigate possible contributions of changes in ligand binding of this receptor in LID in post-mortem brain specimens from Parkinson's disease patients (n=14) and control subjects (n=11), and from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys treated with saline (n=5), L-DOPA (n=4) or L-DOPA+2-methyl-6-(phenylethynyl)pyridine (MPEP) (n=5), and control monkeys (n=4). MPEP is the prototypal metabotropic glutamate 5 (mGlu5) receptor antagonist and has been shown to reduce the development of LID in these monkeys in a chronic treatment of one month. [3H]GR125743 specific binding to striatal and pallidal 5-HT1B receptors respectively were only increased in L-DOPA-treated MPTP monkeys (dyskinetic monkeys) as compared to controls, saline and L-DOPA+MPEP MPTP monkeys; dyskinesias scores correlated positively with this binding. Parkinson's disease patients with motor complications (L-DOPA-induced dyskinesias and wearing-off) had higher [3H]GR125743 specific binding compared to those without motor complications and controls in the basal ganglia. Reduction of motor complications was associated with normal striatal 5-HT1B receptors, suggesting the potential of this receptor for the management of motor complications in Parkinson's disease.

  18. Hepatocyte Toll-like receptor 4 regulates obesity-induced inflammation and insulin resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chronic low-grade inflammation is a hallmark of obesity and thought to contribute to the development of obesity-related insulin resistance. Toll-like receptor 4 (Tlr4) is a key mediator of pro-inflammatory responses. Mice lacking Tlr4s are protected from diet-induced insulin resistance and inflammat...

  19. Evidence that the anorexia induced by lipopolysaccharide is mediated by the 5-HT2C receptor.

    PubMed

    von Meyenburg, Claudia; Langhans, Wolfgang; Hrupka, Brian J

    2003-01-01

    Rats consistently reduce their food intake following injections of bacterial lipopolysaccharides (LPS). Because inhibition of serotonergic (5-HT) activity by 8-OH-DPAT (5-HT(1A) activation) attenuates LPS-induced anorexia, we conducted a series of studies to examine whether other 5-HT-receptors are involved in the mediation of peripheral LPS-induced anorexia. In all experiments, rats were injected with LPS (100 microg/kg body weight [BW] ip) at lights out (hour 0). Antagonists were administered peripherally at hour 4, shortly after the onset of anorexia, which presumably follows the enhanced cytokine production after LPS. Food intake was then recorded during the subsequent 2 h or longer. 5-HT receptor antagonists cyanopindolol and SB 224289 (5-HT(1B)), ketanserin (5-HT(2A)), RS-102221 (5-HT(2C)), and metoclopramide (5-HT(3)) failed to attenuate LPS-induced anorexia. In contrast, both ritanserin (5-HT(2A/C)-receptor antagonist) (0.5 mg/kg BW) and SB 242084 (5-HT(2C)) (0.3 mg/kg BW) attenuated LPS-induced anorexia at doses that did not alter food intake in non-LPS-treated rats (all P<.01). Our results suggest that at least part of the anorexia following peripheral LPS administration is mediated through an enhanced 5-HT-ergic activity and the 5-HT(2C) receptor.

  20. Profound and rapid reduction in body temperature induced by the melanocortin receptor agonists

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid red...

  1. MECHANISMS OF ZN-INDUCED SIGNAL INITIATION THROUGH THE EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR)

    EPA Science Inventory

    MECHANISMS OF Zn-INDUCED SIGNAL INITIATION THROUGH THE EPIDERMAL GROWTH FACTOR RECEPTOR (EGFR)
    James M. Samet*, Lee M. Graves? and Weidong Wu?. *Human Studies Division, NHEERL, ORD, Research Triangle Park, NC 27711, and ?Center for Environmental Medicine, University of North C...

  2. Blockade of calcium-permeable AMPA receptors protects hippocampal neurons against global ischemia-induced death

    PubMed Central

    Noh, Kyung-Min; Yokota, Hidenori; Mashiko, Toshihiro; Castillo, Pablo E.; Zukin, R. Suzanne; Bennett, Michael V. L.

    2005-01-01

    Transient global or forebrain ischemia induced experimentally in animals can cause selective, delayed neuronal death of hippocampal CA1 pyramidal neurons. A striking feature is a delayed rise in intracellular free Zn2+ in CA1 neurons just before the onset of histologically detectable cell death. Here we show that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs) at Schaffer collateral to CA1 synapses in postischemic hippocampus exhibit properties of Ca2+/Zn2+-permeable, Glu receptor 2 (GluR2)-lacking AMPARs before the rise in Zn2+ and cell death. At 42 h after ischemia, AMPA excitatory postsynaptic currents exhibited pronounced inward rectification and marked sensitivity to 1-naphthyl acetyl spermine (Naspm), a selective channel blocker of GluR2-lacking AMPARs. In control hippocampus, AMPA excitatory postsynaptic currents were electrically linear and relatively insensitive to Naspm. Naspm injected intrahippocampally at 9-40 h after insult greatly reduced the late rise in intracellular free Zn2+ in postischemic CA1 neurons and afforded partial protection against ischemia-induced cell death. These results implicate GluR2-lacking AMPA receptors in the ischemia-induced rise in free Zn2+ and death of CA1 neurons, although a direct action at the time of the rise in Zn2+ is unproven. This receptor subtype appears to be an important therapeutic target for intervention in ischemia-induced neuronal death in humans. PMID:16093311

  3. Garlic (Allium sativum) Extracts Inhibits Lipopolysaccharide-Induced Toll-Like Receptor 4 Dimerization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Garlic has been used as a folk medicine for a long history. Numerous studies demonstrated that garlic extracts and its sulfur-containing compounds inhibit nuclear factor-kappa B (NF-kB) activation induced by various receptor agonist including lipopolysaccharide (LPS). These effects suggest that garl...

  4. Serotonergic modulation in neuropathy induced by oxaliplatin: effect on the 5HT2C receptor.

    PubMed

    Baptista-de-Souza, Daniela; Di Cesare Mannelli, Lorenzo; Zanardelli, Matteo; Micheli, Laura; Nunes-de-Souza, Ricardo Luiz; Canto-de-Souza, Azair; Ghelardini, Carla

    2014-07-15

    Fluoxetine has been shown to be effective in clinical and experimental studies of neuropathic pain. Besides to increase serotonin levels in the synaptic cleft, fluoxetine is able to block the serotonergic 5-HT2C receptor subtype, which in turn has been involved in the modulation of neuropathic pain. This study investigated the effect of repeated treatments with fluoxetine on the neuropathic nociceptive response induced by oxaliplatin and the effects of both treatments on 5-HT2C receptor mRNA expression and protein levels in the rat spinal cord (SC), rostral ventral medulla (RVM), midbrain periaqueductal gray (PAG) and amygdala (Amy). Nociception was assessed by paw-pressure, cold plate and Von Frey tests. Fluoxetine prevented mechanical hypersensitivity and pain threshold alterations induced by oxaliplatin but did not prevent the impairment in weight gain induced by this anticancer drug. Ex vivo analysis revealed that oxaliplatin increased the 5-HT2C receptor mRNA expression and protein levels in the SC and PAG. Similar effects were observed in fluoxetine-treated animals but only within the PAG. While oxaliplatin decreased the 5-HT2C mRNA expression levels in the Amy, fluoxetine increased their protein levels in this area. Fluoxetine impaired the oxaliplatin effects on the 5-HT2C receptor mRNA expression in the SC and Amy and protein levels in the SC. All treatments increased of 5-HT2C receptor mRNA expression and protein levels in the PAG. These results suggest that the effects of fluoxetine on neuropathic pain induced by oxaliplatin are associated with quantitative changes in the 5-HT2C receptors located within important areas of the nociceptive system.

  5. Involvement of prefrontal AMPA receptors in encounter stimulation-induced hyperactivity in isolation-reared mice.

    PubMed

    Araki, Ryota; Ago, Yukio; Hasebe, Shigeru; Nishiyama, Saki; Tanaka, Tatsunori; Oka, Satoshi; Takuma, Kazuhiro; Matsuda, Toshio

    2014-06-01

    We recently showed that social encounter stimulation induces hyperactivity in mice reared in social isolation from early life and this is associated with the transient activation of prefrontal dopaminergic and serotonergic systems. In the present study, we examined the effect of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor antagonist 2, 3-dioxo-6-nitro-1, 2, 3, 4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX) on encounter-induced behavioural and neurochemical changes to study the role of the receptor in abnormal behaviours in isolation-reared mice. The encounter to an intruder mouse induced hyperactivity with transient increases in prefrontal dopamine and serotonin levels in isolation-reared mice. NBQX attenuated the encounter-induced hyperactivity and the associated neurochemical changes in isolation-reared mice. In addition, NBQX reduced aggressive behaviour and cognitive impairment in isolation-reared mice, but did not affect depressive-like behaviour or spontaneous hyper-locomotion in these animals. The AMPA receptor agonist (S)-AMPA increased prefrontal dopamine and serotonin release, and this effect was higher in isolation-reared mice than in the group-reared mice, suggesting higher prefrontal AMPA receptor activity in isolation-reared mice. Furthermore, isolation rearing increased the expression of AMPA receptor subunits (GluR1, GluR2 and GluR3) and GluR1 Ser845 phosphorylation in the prefrontal cortex, but not in the hippocampus or nucleus accumbens. Taken together, these results suggest that an increase in AMPA receptor activity in the prefrontal cortex contributes to some, but not all, abnormal behaviours in isolation-reared mice.

  6. Mechanisms of the adenosine A2A receptor-induced sensitization of esophageal C fibers.

    PubMed

    Brozmanova, M; Mazurova, L; Ru, F; Tatar, M; Hu, Y; Yu, S; Kollarik, M

    2016-02-01

    Clinical studies indicate that adenosine contributes to esophageal mechanical hypersensitivity in some patients with pain originating in the esophagus. We have previously reported that the esophageal vagal nodose C fibers express the adenosine A2A receptor. Here we addressed the hypothesis that stimulation of the adenosine A2A receptor induces mechanical sensitization of esophageal C fibers by a mechanism involving transient receptor potential A1 (TRPA1). Extracellular single fiber recordings of activity originating in C-fiber terminals were made in the ex vivo vagally innervated guinea pig esophagus. The adenosine A2A receptor-selective agonist CGS21680 induced robust, reversible sensitization of the response to esophageal distention (10-60 mmHg) in a concentration-dependent fashion (1-100 nM). At the half-maximally effective concentration (EC50: ≈3 nM), CGS21680 induced an approximately twofold increase in the mechanical response without causing an overt activation. This sensitization was abolished by the selective A2A antagonist SCH58261. The adenylyl cyclase activator forskolin mimicked while the nonselective protein kinase inhibitor H89 inhibited mechanical sensitization by CGS21680. CGS21680 did not enhance the response to the purinergic P2X receptor agonist α,β-methylene-ATP, indicating that CGS21680 does not nonspecifically sensitize to all stimuli. Mechanical sensitization by CGS21680 was abolished by pretreatment with two structurally different TRPA1 antagonists AP18 and HC030031. Single cell RT-PCR and whole cell patch-clamp studies in isolated esophagus-specific nodose neurons revealed the expression of TRPA1 in A2A-positive C-fiber neurons and demonstrated that CGS21682 potentiated TRPA1 currents evoked by allylisothiocyanate. We conclude that stimulation of the adenosine A2A receptor induces mechanical sensitization of nodose C fibers by a mechanism sensitive to TRPA1 antagonists indicating the involvement of TRPA1.

  7. Reticulocyte haemoglobin content vs. soluble transferrin receptor and ferritin index in iron deficiency anaemia accompanied with inflammation.

    PubMed

    Marković, M; Majkić-Singh, N; Ignjatović, S; Singh, S

    2007-10-01

    Ferritin concentration, as a parameter of iron status that is commonly used in the diagnosis of iron deficiency anaemia (IDA), often has limited values if the iron deficiency is accompanied by inflammatory disease. This study evaluated the value of reticulocyte haemoglobin content (CHr) and soluble transferrin receptor-ferritin index (sTfR/F) in the diagnosis of IDA and differential diagnosis of IDA and anaemia of chronic disease. The study included 66 nonanaemic individuals as controls, 86 patients with IDA divided into noninflammatory and inflammatory subgroups, and 32 patients with anaemia of chronic disease. Blood count, iron, transferrin saturation, total iron binding capacity, ferritin, C-reactive protein, sTfR and CHr were determined. Receiver operator characteristic curve analysis showed very high discriminating power for CHr, soluble transferrin receptor (sTfR) and sTfR/F in the diagnosis of IDA. In patients with anaemia of chronic disease these parameters showed no significant difference from the control. CHr and sTfR enabled recognition of iron deficiency and were not affected by acute phase reaction. They are sensitive markers of body iron status with additional value to conventional tests for the detection of iron deficiency.

  8. Exposure to nicotine increases dopamine receptor content in the mesocorticolimbic pathway of rat dams and offspring during lactation.

    PubMed

    Pinheiro, C R; Oliveira, E; Manhães, A C; Fraga, M C; Claudio-Neto, S; Younes-Rapozo, V; Lotufo, B M; Moura, E G; Lisboa, P C

    2015-09-01

    Nicotine exposure causes the release of dopamine from the ventral tegmental area (VTA) to the nucleus accumbens (NAc). We have previously shown that maternal exposure to nicotine during lactation causes hyperleptinemia in dams and pups, and leptin is known to decrease dopamine release from the VTA. Here we evaluated whether maternal exposure to nicotine during lactation causes changes in dopamine and leptin signaling pathways at the end of exposure and after 5days of withdrawal in the: VTA, NAc, arcuate nucleus (ARC) and dorsal striatum (DS). On postnatal day (PN) 2, lactating Wistar rats were implanted with minipumps releasing nicotine (NIC; 6mg/kg/day, s.c.) or saline (C) for 14days. Offspring were tested in the elevated plus maze (EPM) and open field on PN14 or PN20, and euthanized on PN15 or PN21. Entries into the open arms and head dips in the EPM were reduced in NIC pups at P20. At weaning (PN21), NIC dams had: lower tyrosine hydroxylase (TH), higher OBRb and SOCS3 contents in VTA; lower TH, higher D1R, D2R and DAT contents in NAc; higher TH content in DS; and higher D2R and SOCS3 contents in ARC. On PN15, NIC offspring had higher D1R, D2R and lower DAT contents in NAc, while on PN21, they had lower DAT in DS, and lower pSTAT3 content in ARC. We evidenced that postnatal nicotine exposure induces relevant changes in the brain reward system of dams and pups, possibly associated with changes in leptinemia and increased offspring anxiety-like behavior.

  9. Mammary tumorigenesis induced by fibroblast growth factor receptor 1 requires activation of the epidermal growth factor receptor.

    PubMed

    Bade, Lindsey K; Goldberg, Jodi E; Dehut, Hazel A; Hall, Majken K; Schwertfeger, Kathryn L

    2011-09-15

    Fibroblast growth factor receptor 1 (FGFR1) is an oncoprotein with known involvement in mammary tumorigenesis. To understand how FGFR1 signaling promotes mammary tumorigenesis, an inducible FGFR1 (iFGFR1) system was created previously. Previous studies have demonstrated that upon iFGFR1 activation in vivo, the epidermal growth factor (EGF) ligands amphiregulin (AREG) and epiregulin (EREG) are upregulated. Both AREG and EREG interact with the EGF receptor (EGFR). Here, we investigated whether the FGFR1-induced increase in AREG and EREG expression might coordinately increase EGFR signaling to promote mammary tumorigenesis. Treatment of mouse mammary epithelial cells with either AREG or EREG conferred a greater migratory potential, increased cellular proliferation and increased extracellular regulated kinase 1/2 (ERK1/2) activation. These effects could be blocked with the EGFR-specific inhibitor erlotinib, suggesting that they are EGFR-dependent. In transgenic mice with iFGFR1 under the control of the mouse mammary tumor virus (MMTV) promoter, iFGFR1 activation also led to increased mammary epithelial cell proliferation that was inhibited with erlotinib. Taken together, these data suggest that AREG and EREG mediate tumorigenic phenotypes by activating EGFR signaling, and that the oncogenic potential of FGFR1 requires EGFR activation to promote mammary tumorigenesis.

  10. Early role of the κ opioid receptor in ethanol-induced reinforcement.

    PubMed

    Pautassi, Ricardo Marcos; Nizhnikov, Michael E; Acevedo, Ma Belén; Spear, Norman E

    2012-03-20

    Effects of early ethanol exposure on later ethanol intake emphasize the importance of understanding the neurobiology of ethanol-induced reinforcement early in life. Infant rats exhibit ethanol-induced appetitive conditioning and ethanol-induced locomotor activation, which have been linked in theory and may have mechanisms in common. The appetitive effects of ethanol are significantly modulated by μ and δ opioid receptors, whereas μ but not δ receptors are involved in the motor stimulant effects of ethanol during early development. The involvement of the κ opioid receptor (KOR) system in the motivational effects of ethanol has been much less explored. The present study assessed, in preweanling (infant) rats, the modulatory role of the KOR system in several paradigms sensitive to ethanol-induced reinforcement. Kappa opioid activation and blockade were examined in second-order conditioned place preference with varied timing before conditioning and with varied ethanol doses. The role of KOR on ethanol-induced locomotion and ethanol-induced taste conditioning was also explored. The experiments were based on the assumption that ethanol concurrently induces appetitive and aversive effects and that the latter may be mediated by activation of kappa receptors. The main result was that blockade of kappa function facilitated the expression of appetitive ethanol reinforcement in terms of tactile and taste conditioning. The effects of kappa activation on ethanol conditioning seemed to be independent from ethanol's stimulant effects. Kappa opioid activation potentiated the motor depressing effects of ethanol but enhanced motor activity in control subjects. Overall, the results support the hypothesis that a reduced function of the KOR system in nondependent subjects should attenuate the aversive consequences of ethanol.

  11. Influence of different histamine receptor agonists and antagonists on apomorphine-induced licking behavior in rat.

    PubMed

    Farzin, D; Attarzadeh, M

    2000-09-15

    The effects of different histamine receptor agonists and antagonists on apomorphine-induced licking behavior in rats were investigated. Subcutaneous (s.c.) injection of various doses of apomorphine (0. 125-1.25 mg/kg) induced licking. The licking response was counted by direct observation and recorded for a 75-min period. Intracerebroventricular (i.c.v.) or intraperitoneal (i.p.) injection of the histamine H(1) or H(2) receptor agonist, HTMT (6-[2-(4-imidazolyl)ethylamino]-N-(4-trifluoromethylphenyl) heptanecarboxamide) (50 and 100 microg per rat), or dimaprit (10 and 15 mg/kg, i.p.), respectively, potentiated apomorphine-induced licking, while the histamine H(3) receptor agonist, imetit (5 and 10 mg/kg, i.p.), reduced the licking response induced by apomorphine. Pretreatment with various histamine receptor antagonists, dexchlorpheniramine (30 and 40 mg/kg, i.p.), diphenhydramine (20, 30 and 40 mg/kg, i.p.), famotidine (30 and 40 mg/kg, s.c.) and ranitidine (20, 30 and 40 mg/kg), reduced apomorphine-induced licking, while thioperamide (5 and 10 mg/kg, i.p.) potentiated the apomorphine effect. The effects of HTMT and dimaprit were blocked by dexchlorpheniramine (20 mg/kg, i.p.) and famotidine (20 mg/kg, s.c.), respectively. The inhibitory effect elicited by imetit on apomorphine-induced licking behavior was also abolished in animals treated with thioperamide (2.5 mg/kg, i.p.). The results suggest that histaminergic mechanisms may be involved in the modulation of apomorphine-induced licking behavior.

  12. Early role of the κ opioid receptor in ethanol-induced reinforcement

    PubMed Central

    Pautassi, Ricardo Marcos; Nizhnikov, Michael E.; Acevedo, Ma. Belén; Spear, Norman E.

    2012-01-01

    Effects of early ethanol exposure on later ethanol intake emphasize the importance of understanding the neurobiology of ethanol-induced reinforcement early in life. Infant rats exhibit ethanol-induced appetitive conditioning and ethanol-induced locomotor activation, which have been linked in theory and may have mechanisms in common. The appetitive effects of ethanol are significantly modulated by μ and δ opioid receptors, whereas μ but not δ receptors are involved in the motor stimulant effects of ethanol during early development. The involvement of the κ opioid receptor (KOR) system in the motivational effects of ethanol has been much less explored. The present study assessed, in preweanling (infant) rats, the modulatory role of the KOR system in several paradigms sensitive to ethanol-induced reinforcement. Kappa opioid activation and blockade was examined in second-order conditioned place preference with varied timing before conditioning and with varied ethanol doses. The role of KOR on ethanol-induced locomotion and ethanol-induced taste conditioning was also explored. The experiments were based on the assumption that ethanol concurrently induces appetitive and aversive effects and that the latter may be mediated by activation of kappa receptors. The main result was that blockade of kappa function facilitated the expression of appetitive ethanol reinforcement in terms of tactile and taste conditioning. The effects of kappa activation on ethanol conditioning seemed to be independent from ethanol's stimulant effects. Kappa opioid activation potentiated the motor depressing effects of ethanol but enhanced motor activity in control subjects. Overall, the results support the hypothesis that a reduced function of the KOR system in nondependent subjects should attenuate the aversive consequences of ethanol. PMID:22261437

  13. Lysosomal Function Is Involved in 17β-Estradiol-Induced Estrogen Receptor α Degradation and Cell Proliferation

    PubMed Central

    Marino, Maria; Acconcia, Filippo

    2014-01-01

    The homeostatic control of the cellular proteome steady-state is dependent either on the 26S proteasome activity or on the lysosome function. The sex hormone 17β-estradiol (E2) controls a plethora of biological functions by binding to the estrogen receptor α (ERα), which is both a nuclear ligand-activated transcription factor and also an extrinsic plasma membrane receptor. Regulation of E2-induced physiological functions (e.g., cell proliferation) requires the synergistic activation of both transcription of estrogen responsive element (ERE)-containing genes and rapid extra-nuclear phosphorylation of many different signalling kinases (e.g., ERK/MAPK; PI3K/AKT). Although E2 controls ERα intracellular content and activity via the 26S proteasome-mediated degradation, biochemical and microscopy-based evidence suggests a possible cross-talk among lysosomes and ERα activities. Here, we studied the putative localization of endogenous ERα to lysosomes and the role played by lysosomal function in ERα signalling. By using confocal microscopy and biochemical assays, we report that ERα localizes to lysosomes and to endosomes in an E2-dependent manner. Moreover, the inhibition of lysosomal function obtained by chloroquine demonstrates that, in addition to 26S proteasome-mediated receptor elimination, lysosome-based degradation also contributes to the E2-dependent ERα breakdown. Remarkably, the lysosome function is further involved in those ERα activities required for E2-dependent cell proliferation while it is dispensable for ERα-mediated ERE-containing gene transcription. Our discoveries reveal a novel lysosome-dependent degradation pathway for ERα and show a novel biological mechanism by which E2 regulates ERα cellular content and, as a consequence, cellular functions. PMID:24736371

  14. Regulation of Glutamate Release by α7 Nicotinic Receptors: Differential Role in Methamphetamine-Induced Damage to Dopaminergic and Serotonergic Terminals

    PubMed Central

    Northrop, Nicole A.; Smith, Laura P.; Eyerman, David J.

    2011-01-01

    Regulation of glutamate release is an important underlying mechanism in mediating excitotoxic events such as damage to dopamine (DA) and serotonin (5-HT) neurons observed after exposure to methamphetamine (Meth). One way to regulate glutamate release may be through the modulation of α7 nicotinic acetylcholine (nACh) receptors. Meth administration is known to increase acetylcholine release; however, it is unknown whether Meth increases glutamate release and causes long-term damage to both DA and 5-HT terminals through the activation of α7 nACh receptors. To test this hypothesis, the α7 nACh receptor antagonist, methyllycaconitine (MLA), was administered before the administration of repeated doses of Meth while simultaneously monitoring extracellular striatal glutamate with in vivo microdialysis. In addition, the subsequent long-term decreases in markers of dopaminergic and serotonergic terminals, including DA reuptake transporter (DAT), serotonin reuptake transporter (SERT), vesicular monoamine transporter-2, vesicular DA, and vesicular 5-HT content in the rat striatum, were measured. The results show that MLA pretreatment prevented Meth-induced increases in striatal glutamate and protected against the subsequent long-term decreases in striatal DAT and vesicular DA content without affecting the hyperthermia produced by Meth. In contrast, the Meth-induced decreases in striatal SERT immunoreactivity and vesicular 5-HT content were not affected by MLA. This suggests that the α7 nACh receptor differentially mediates glutamate-dependent damage to DA but not 5-HT terminals in a manner that is independent of hyperthermia. Furthermore, antagonism of α7 nACh receptors may be a possible therapeutic strategy for decreasing extracellular glutamate and preventing the excitotoxic damage observed in other DA-related neurodegenerative disorders. PMID:21159748

  15. The serotonin 2C receptor potently modulates the head-twitch response in mice induced by a phenethylamine hallucinogen

    PubMed Central

    Canal, Clinton E.; Olaghere da Silva, Uade B.; Gresch, Paul J.; Watt, Erin E.; Sanders-Bush, Elaine

    2010-01-01

    Rationale Hallucinogenic serotonin 2A (5-HT2A) receptor partial agonists, such as (±)-1-(2,5-dimethoxy-4-iodo-phenyl)-2-aminopropane hydrochloride (DOI), induce a frontal cortex-dependent head-twitch response (HTR) in rodents, a behavioral proxy of a hallucinogenic response that is blocked by 5-HT2A receptor antagonists. In addition to 5-HT2A receptors, DOI and most other serotonin-like hallucinogens have high affinity and potency as partial agonists at 5-HT2C receptors. Objectives We tested for involvement of 5-HT2C receptors in the HTR induced by DOI. Results Comparison of 5-HT2C receptor knockout and wild-type littermates revealed an approximately 50% reduction in DOI-induced HTR in knockout mice. Also, pretreatment with either the 5-HT2C receptor antagonist SB206553 or SB242084 eradicated a twofold difference in DOI-induced HTR between the standard inbred mouse strains C57BL/6J and DBA/2J, and decreased the DOI-induced HTR by at least 50% in both strains. None of several measures of 5-HT2A receptors in frontal cortex explained the strain difference, including 5-HT2A receptor density, Gαq or Gαi/o protein levels, phospholipase C activity, or DOI-induced expression of Egr1 and Egr2. 5-HT2C receptor density in the brains of C57BL/6J and DBA/2J was also equivalent, suggesting that 5-HT2C receptor-mediated intracellular signaling or other physiological modulators of the HTR may explain the strain difference in response to DOI. Conclusions We conclude that the HTR to DOI in mice is strongly modulated by 5-HT2C receptor activity. This novel finding invites reassessment of hallucinogenic mechanisms involving 5-HT2 receptors. PMID:20165943

  16. KCTD Hetero-oligomers Confer Unique Kinetic Properties on Hippocampal GABAB Receptor-Induced K+ Currents.

    PubMed

    Fritzius, Thorsten; Turecek, Rostislav; Seddik, Riad; Kobayashi, Hiroyuki; Tiao, Jim; Rem, Pascal D; Metz, Michaela; Kralikova, Michaela; Bouvier, Michel; Gassmann, Martin; Bettler, Bernhard

    2017-02-01

    GABAB receptors are the G-protein coupled receptors for the main inhibitory neurotransmitter in the brain, GABA. GABAB receptors were shown to associate with homo-oligomers of auxiliary KCTD8, KCTD12, KCTD12b, and KCTD16 subunits (named after their T1 K(+)-channel tetramerization domain) that regulate G-protein signaling of the receptor. Here we provide evidence that GABAB receptors also associate with hetero-oligomers of KCTD subunits. Coimmunoprecipitation experiments indicate that two-thirds of the KCTD16 proteins in the hippocampus of adult mice associate with KCTD12. We show that the KCTD proteins hetero-oligomerize through self-interacting T1 and H1 homology domains. Bioluminescence resonance energy transfer measurements in live cells reveal that KCTD12/KCTD16 hetero-oligomers associate with both the receptor and the G-protein. Electrophysiological experiments demonstrate that KCTD12/KCTD16 hetero-oligomers impart unique kinetic properties on G-protein-activated Kir3 currents. During prolonged receptor activation (one min) KCTD12/KCTD16 hetero-oligomers produce moderately desensitizing fast deactivating K(+) currents, whereas KCTD12 and KCTD16 homo-oligomers produce strongly desensitizing fast deactivating currents and nondesensitizing slowly deactivating currents, respectively. During short activation (2 s) KCTD12/KCTD16 hetero-oligomers produce nondesensitizing slowly deactivating currents. Electrophysiological recordings from hippocampal neurons of KCTD knock-out mice are consistent with these findings and indicate that KCTD12/KCTD16 hetero-oligomers increase the duration of slow IPSCs. In summary, our data demonstrate that simultaneous assembly of distinct KCTDs at the receptor increases the molecular and functional repertoire of native GABAB receptors and modulates physiologically induced K(+) current responses in the hippocampus.

  17. Prevention of Stimulant Induced Euphoria with an Opioid Receptor Antagonist

    DTIC Science & Technology

    2013-10-01

    ADHD symptoms over the course of the 6-week trial 15. SUBJECT TERMS- Clinical trial, methylphenidate, naltrexone, ADHD stimulant induced euphoria...In this double-blind study, subjects will receive methylphenidate and naltrexone or a placebo to treat their ADHD symptoms over the course of the 6...The Study Coordinator and Research Assistant have been trained to administer an IRB- approved phone screen asking about past and current ADHD symptoms

  18. Human P2X7 receptor activation induces the rapid shedding of CXCL16.

    PubMed

    Pupovac, Aleta; Foster, Christopher M; Sluyter, Ronald

    2013-03-22

    Activation of the purinergic P2X7 receptor by extracellular ATP induces the shedding of cell-surface molecules including the low-affinity IgE receptor, CD23 from leukocytes. CD23 is a known substrate of a disintegrin and metalloprotease (ADAM)10. The aim of the current study was to determine if P2X7 activation induced the shedding of the chemokine CXCL16, an ADAM10 substrate. Using immunolabelling and flow cytometry we demonstrate that human RPMI 8226 multiple myeloma B cells, which have been previously shown to express P2X7, also express CXCL16. Flow cytometric and ELISA measurements of ATP-induced loss of cell-surface CXCL16 showed that ATP treatment of RPMI 8226 cells induced the rapid shedding of CXCL16. Treatment of RPMI 8226 cells with the specific P2X7 antagonists, AZ10606120 and KN-62 impaired ATP-induced CXCL16 shedding by ~86% and ~90% respectively. RT-PCR demonstrated that ADAM10 is expressed in these cells and treatment of cells with the ADAM10 inhibitor, GI254023X, impaired ATP-induced CXCL16 shedding by ~87%. GI254023X also impaired P2X7-induced CD23 shedding by ∼57%. This data indicates that human P2X7 activation induces the rapid shedding of CXCL16 and that this process involves ADAM10.

  19. Rimonabant, a selective cannabinoid1 receptor antagonist, protects against light-induced retinal degeneration in vitro and in vivo.

    PubMed

    Imamura, Tomoyo; Tsuruma, Kazuhiro; Inoue, Yuki; Otsuka, Tomohiro; Ohno, Yuta; Ogami, Shiho; Yamane, Shinsaku; Shimazawa, Masamitsu; Hara, Hideaki

    2017-03-16

    The endocannabinoid system is involved in some neurodegenerative diseases such as Alzheimer's disease. An endogenous constellation of proteins related to cannabinoid1 receptor signaling, including free fatty acids, diacylglycerol lipase, and N-acylethanolamine-hydrolyzing acid amidase, are localized in the murine retina. Moreover, the expression levels of endogenous agonists of cannabinoid receptors are changed in the vitreous fluid. However, the role of the endocannabinoid system in the retina, particularly in the light-induced photoreceptor degeneration, remains unknown. Therefore, we investigated involvement of the cannabinoid1 receptor in light-induced retinal degeneration using in vitro and in vivo models. To evaluate the effect of cannabinoid1 receptors in light irradiation-induced cell death, the mouse retinal cone-cell line (661W) was treated with a cannabinoid1 receptor antagonist, rimonabant. Time-dependent changes of expression and localization of retinal cannabinoid1 receptors were measured using Western blot and immunostaining. Retinal damage was induced in mice by exposure to light, followed by intravitreal injection of rimonabant. Electroretinograms and histologic analyses were performed. Rimonabant suppressed light-induced photoreceptor cell death. Cannabinoid1 receptor expression was upregulated by light exposure. Treatment with rimonabant improved both a- and b-wave amplitudes and the thickness of the outer nuclear layer. These results suggest that the cannabinoid1 receptor is involved in light-induced retinal degeneration and it may represent a therapeutic target in the light-induced photoreceptor degeneration related diseases.

  20. The activation of liver X receptors inhibits toll-like receptor-9-induced foam cell formation.

    PubMed

    Sorrentino, Rosalinda; Morello, Silvana; Chen, Shuang; Bonavita, Eduardo; Pinto, Aldo

    2010-04-01

    Toll-like receptors (TLRs) are related to foam cell formation (FCF), key event in the establishment/progression of atherosclerosis. The activation of TLR2 and TLR4 can increase FCF. The aim of this study was to evaluate the role of TLR9 in FCF. Murine macrophages were treated with CpG-ODN, TLR9 agonist, and oxidized particles of LDL (Paz-PC) and FCF was analyzed by means of Oil Red O staining. The administration of CpG-ODN plus Paz-PC onto macrophages increased the amount of lipid droplets, correlated to increased levels of tumor necrosis factor (TNF)-alpha, IFNbeta, and IP-10. The underlying mechanism by which TLR9 ligation influenced Paz-PC in the FCF was NF-kappaB- and IRF7-dependent, as observed by higher levels of phosphorylated IkappaBalpha, increased nuclear translocation of the p65 subunit, lower levels of the total IKKalpha protein and higher release of interferon-dependent cytokines, such as IP-10. Liver X receptors (LXRs) regulate lipid cellular transport and negatively modulate TLR-dependent signaling pathways. Indeed, the addition of GW3965, synthetic LXRs agonist, significantly reduced FCF after CpG-ODN plus Paz-PC stimulation. In this condition, we observed decreased levels of the nuclear translocation of the p65 subunit, related to the higher presence of LXRalpha into the nucleus. TNF-alpha, IP-10, and IFNbeta levels were reduced by the administration of GW3965 following CpG-ODN and Paz-PC treatment. In conclusion, the activation of TLR9 facilitates the formation of foam cells in an NF-kappaB- and IRF7-dependent manner, countered by the activation of LXRs. This study further support LXRs as potential anti-atherosclerotic target.

  1. A high-content screening assay for small-molecule modulators of oncogene-induced senescence.

    PubMed

    Bitler, Benjamin G; Fink, Lauren S; Wei, Zhi; Peterson, Jeffrey R; Zhang, Rugang

    2013-10-01

    Cellular senescence is a state of stable cell growth arrest. Activation of oncogenes such as RAS in mammalian cells typically triggers cellular senescence. Oncogene-induced senescence (OIS) is an important tumor suppression mechanism, and suppression of OIS contributes to cell transformation. Oncogenes trigger senescence through a multitude of incompletely understood downstream signaling events that frequently involve protein kinases. To identify target proteins required for RAS-induced senescence, we developed a small-molecule screen in primary human fibroblasts undergoing senescence induced by oncogenic RAS (H-Ras(G12V)). Using a high-content imaging system to monitor two hallmarks of senescence, senescence-associated β-galactosidase activity expression and inhibition of proliferation, we screened a library of known small-molecule kinase inhibitors for those that suppressed OIS. Identified compounds were subsequently validated and confirmed using a third marker of senescence, senescence-associated heterochromatin foci. In summary, we have established a novel high-content screening platform that may be useful for elucidating signaling pathways mediating OIS by targeting critical pathway components.

  2. Glucagon receptor antagonism induces increased cholesterol absorption[S

    PubMed Central

    Guan, Hong-Ping; Yang, Xiaodong; Lu, Ku; Wang, Sheng-Ping; Castro-Perez, Jose M.; Previs, Stephen; Wright, Michael; Shah, Vinit; Herath, Kithsiri; Xie, Dan; Szeto, Daphne; Forrest, Gail; Xiao, Jing Chen; Palyha, Oksana; Sun, Li-Ping; Andryuk, Paula J.; Engel, Samuel S.; Xiong, Yusheng; Lin, Songnian; Kelley, David E.; Erion, Mark D.; Davis, Harry R.; Wang, Liangsu

    2015-01-01

    Glucagon and insulin have opposing action in governing glucose homeostasis. In type 2 diabetes mellitus (T2DM), plasma glucagon is characteristically elevated, contributing to increased gluconeogenesis and hyperglycemia. Therefore, glucagon receptor (GCGR) antagonism has been proposed as a pharmacologic approach to treat T2DM. In support of this concept, a potent small-molecule GCGR antagonist (GRA), MK-0893, demonstrated dose-dependent efficacy to reduce hyperglycemia, with an HbA1c reduction of 1.5% at the 80 mg dose for 12 weeks in T2DM. However, GRA treatment was associated with dose-dependent elevation of plasma LDL-cholesterol (LDL-c). The current studies investigated the cause for increased LDL-c. We report findings that link MK-0893 with increased glucagon-like peptide 2 and cholesterol absorption. There was not, however, a GRA-related modulation of cholesterol synthesis. These findings were replicated using structurally diverse GRAs. To examine potential pharmacologic mitigation, coadministration of ezetimibe (a potent inhibitor of cholesterol absorption) in mice abrogated the GRA-associated increase of LDL-c. Although the molecular mechanism is unknown, our results provide a novel finding by which glucagon and, hence, GCGR antagonism govern cholesterol metabolism. PMID:26373568

  3. Influence of adenosine receptors on the development of caerulein-induced acute pancreatitis.

    PubMed

    Szczerbiński, Mariusz; Celiński, Krzysztof; Słomka, Maria; Kasztelan-Szczerbińska, Beata; Cichoz-Lach, Halina

    2002-01-01

    Acute pancreatitis leads to hypoxia caused by vasoconstriction and to activation of lysosomal and digestive enzymes resulting in pancreas autodigestion and damage. This causes activation of leucocytes and increased expression of adhesive molecules enabling margination and adhesion of activated leucocytes to the endothelium. Activated leucocytes are the source of proinflammatory cytokins and oxygen-free radicals which intensify the inflammatory response. The reports indicating that adenosine may prevent activation of the above-mentioned processes in ischaemia prompted us to undertake this study. The study was performed in two stages. The first stage was to evaluate the effects of agonists and antagonists of adenosine receptors on normal pancreas while the second one was to determine the influence of these substances on the development of caerulein-induced acute pancreatitis. During the first stage, the animals were injected intraperitoneally with the substances examined: the A1 receptor antagonist--DPCPX, the A2 receptor agonist--CGS 21680, the A2 receptor antagonist--ZM 241385 and the A3 receptor agonist--IB-MECA and then received intravenous saline. The control animals were subjected only to the 12 h intravenous infusion of 0.15 M NaCl. During the second stage, after the intraperitoneal administration of adenosine receptor agonists and antagonists (as in the first stage), acute pancreatitis was induced with the 12 h intravenous infusion of 5 micrograms/kg/h caerulein. Identical acute pancreatitis was induced in the control animals, however no other substances were administered. The pancreatic tissue samples were collected directly after intravenous infusion. The severity of inflammatory processes in the pancreas was evaluated on the basis of the plasma amylase activity, pancreatic weight and enhancement of histopathological changes observed in this organ. In the animals infused with saline alone, no effects of the substances examined on the pancreatic weight

  4. Medial parabrachial nucleus neurons modulate d-fenfluramine-induced anorexia through 5HT2C receptors.

    PubMed

    Trifunovic, Radmila; Reilly, Steve

    2006-01-05

    We previously reported that lesions of the medial parabrachial nucleus (PBN) enhanced d-fenfluramine (DFEN)-induced anorexia; a finding that suggests these lesions may potentiate the release of serotonin (5HT) or increase the postsynaptic action of 5HT. In the present study, we used SB 206553 (a 5HT2B/2C receptor antagonist) or m-CPP (a 5HT2C/1B receptor agonist) in a standard behavioral procedure (deprivation-induced feeding) to further explore the role of the medial PBN in drug-induced anorexia. In Experiment 1, DFEN (0 or 1.0 mg/kg) was given alone or in combination with SB 206553 (2.0 or 5.0 mg/kg). In Experiment 2, we investigated the food-suppressive effects of m-CPP (0.5, 1.0 or 2.0 mg/kg). The results of Experiment 1 show that SB 206553, while having no influence on the performance of control subjects, attenuated (2.0 mg/kg) or abolished (5 mg/kg) the potentiating effect of the lesions on DFEN-induced anorexia. In Experiment 2, m-CPP induced a suppression of food intake in nonlesioned animals that was significantly potentiated in rats with medial PBN lesions. These results are consistent with the hypothesis that medial PBN neurons mediate anorexia through 5HT2C receptors.

  5. Role of direct estrogen receptor signaling in wear particle-induced osteolysis

    PubMed Central

    Nich, Christophe; Rao, Allison J.; Valladares, Roberto D.; Li, Chenguang; Christman, Jane E.; Antonios, Joseph K.; Yao, Zhenyu; Zwingenberger, Stefan; Petite, Hervé; Hamadouche, Moussa; Goodman, Stuart B.

    2014-01-01

    Estrogen withdrawal following surgical ovariectomy was recently shown to mitigate particle-induced osteolysis in the murine calvarial model. Currently, we hypothesize that estrogen receptors (ERs) were involved in this paradoxical phenomenon. To test this hypothesis, we first evaluated polyethylene (PE) particle-induced osteolysis in the murine calvarial model, using wild type (WT) C57BL6J female mice, ERα deficient (ERαKO) mice, and WT mice either treated with 17β-estradiol (E2) or with the ER pan-antagonist ICI 182,780. According to micro-CT and histomorphometry, we showed that bone resorption was consistently altered in both ERαKO and ICI 182,780 treated mice as compared to WT and E2 groups. Then, we demonstrated that ER disruption consistently decreased both PE and polymethylmethacrylate (PMMA) particle-induced production of TNF-α by murine macrophages in vitro. Similar results were obtained following ER blockade using ICI 182,780 in RAW 264.7 and WT macrophages. ER disruption and pre treatment with ICI 182,780 resulted in a consistent down-regulation of particle-induced TNF-α mRNA expression relative to WT macrophages or untreated RAW cells. These results indicate that the response to wear particles involves estrogen receptors in female mice, as part of macrophage activation. Estrogen receptors may be considered as a future therapeutic target for particle-induced osteolysis. PMID:23113918

  6. CCK1 and CCK2 Receptors Are Expressed on Pancreatic Stellate Cells and Induce Collagen Production

    PubMed Central

    Berna, Marc J.; Seiz, Oliver; Nast, Jan Friso; Benten, Daniel; Bläker, Michael; Koch, Johannes; Lohse, Ansgar W.; Pace, Andrea

    2010-01-01

    The gastrointestinal hormone cholecystokinin (CCK) can induce acute pancreatitis in rodents through its action on acinar cells. Treatment with CCK, in combination with other agents, represents the most commonly used model to induce experimental chronic pancreatitis. Pancreatic stellate cells (PSC) are responsible for pancreatic fibrosis and therefore play a predominant role in the genesis of chronic pancreatitis. However, it is not known whether PSC express CCK receptors. Using real time PCR techniques, we demonstrate that CCK1 and CCK2 receptors are expressed on rat PSC. Interestingly both CCK and gastrin significantly induced type I collagen synthesis. Moreover, both inhibit proliferation. These effects are comparable with TGF-β-stimulated PSC. Furthermore, the natural agonists CCK and gastrin induce activation of pro-fibrogenic pathways Akt, ERK, and Src. Using specific CCK1 and CCK2 receptor (CCK2R) inhibitors, we found that Akt activation is mainly mediated by CCK2R. Akt activation by CCK and gastrin could be inhibited by the PI3K inhibitor wortmannin. Activation of ERK and the downstream target Elk-1 could be inhibited by the MEK inhibitor U0126. These data suggest that CCK and gastrin have direct activating effects on PSC, are able to induce collagen synthesis in these cells, and therefore appear to be important regulators of pancreatic fibrogenesis. Furthermore, similar to TGF-β, both CCK and gastrin inhibit proliferation in PSC. PMID:20843811

  7. Ligustrazine attenuates inflammation and the associated chemokines and receptors in ovalbumine-induced mouse asthma model.

    PubMed

    Wei, Ying; Liu, Jiaqi; Zhang, Hongying; Du, Xin; Luo, Qingli; Sun, Jing; Liu, Feng; Li, Mihui; Xu, Fei; Wei, Kai; Dong, Jingcheng

    2016-09-01

    Ligustrazine which is isolated from Chinese herb ligusticum chuanxiong hort, has been widely used in traditional Chinese medicine (TCM) for asthma treatment. In this study, we aim to observe the effect of ligustrazine on inflammation and the associated chemokines and receptors in ovalbumin (OVA)-induced mouse asthma model. Our data demonstrates that ligustrazine suppresses airway hyperresponsiveness to methacholine and lung inflammation in OVA-induced mouse asthma model. Ligustrazine also induces inhibition of inflammatory cells including neutrophils, lymphocytes and eosinophils. In addition, ligustrazine significantly reduces IL-4, IL-5, IL-17A, CCL3, CCL19 and CCL21 level in BALF of asthma mice. Furthermore, ligustrazine induces down-regulation of CCL19 receptor CCR7, STAT3 and p38 MAPK protein expression. Collectively, these results suggest that ligustrazine is effective in attenuation of allergic airway inflammatory changes and related chemokines and receptors in OVA-induced asthma model, and this action might be associated with inhibition of STAT3 and p38 MAPK pathway, which indicates that ligustrazine may be used as a potential therapeutic method to treat asthma.

  8. A novel and selective melanin-concentrating hormone receptor 1 antagonist ameliorates obesity and hepatic steatosis in diet-induced obese rodent models.

    PubMed

    Kawata, Yayoi; Okuda, Shoki; Hotta, Natsu; Igawa, Hideyuki; Takahashi, Masashi; Ikoma, Minoru; Kasai, Shizuo; Ando, Ayumi; Satomi, Yoshinori; Nishida, Mayumi; Nakayama, Masaharu; Yamamoto, Syunsuke; Nagisa, Yasutaka; Takekawa, Shiro

    2017-02-05

    Melanin-concentrating hormone (MCH), a cyclic neuropeptide expressed predominantly in the lateral hypothalamus, plays an important role in the control of feeding behavior and energy homeostasis. Mice lacking MCH or MCH1 receptor are resistant to diet-induced obesity (DIO) and MCH1 receptor antagonists show potent anti-obesity effects in preclinical studies, indicating that MCH1 receptor is a promising target for anti-obesity drugs. Moreover, recent studies have suggested the potential of MCH1 receptor antagonists for treatment of non-alcoholic fatty liver disease (NAFLD). In the present study, we show the anti-obesity and anti-hepatosteatosis effect of our novel MCH1 receptor antagonist, Compound A. Repeated oral administration of Compound A resulted in dose-dependent body weight reduction and had an anorectic effect in DIO mice. The body weight lowering effect of Compound A was more potent than that of pair-feeding. Compound A also reduced lipid content and the expression level of lipogenesis-, inflammation-, and fibrosis-related genes in the liver of DIO mice. Conversely, intracerebroventricular infusion of MCH caused induction of hepatic steatosis as well as increase in body weight in high-fat diet-fed wild type mice, but not MCH1 receptor knockout mice. The pair-feeding study revealed the MCH-MCH1 receptor system affects hepatic steatosis through a mechanism that is independent of body weight change. Metabolome analysis demonstrated that Compound A upregulated lipid metabolism-related molecules, such as acylcarnitines and cardiolipins, in the liver. These findings suggest that our novel MCH1 receptor antagonist, Compound A, exerts its beneficial therapeutic effect on NAFLD and obesity through a central MCH-MCH1 receptor pathway.

  9. Histamine receptors expressed in circulating progenitor cells have reciprocal actions in ligation-induced arteriosclerosis.

    PubMed

    Yamada, Sohsuke; Wang, Ke-Yong; Tanimoto, Akihide; Guo, Xin; Nabeshima, Atsunori; Watanabe, Takeshi; Sasaguri, Yasuyuki

    2013-09-01

    Histamine is synthesized as a low-molecular-weight amine from L-histidine by histidine decarboxylase (HDC). Recently, we demonstrated that carotid artery-ligated HDC gene-deficient mice (HDC(-/-)) showed less neointimal formation than wild-type (WT) mice, indicating that histamine participates in the process of arteriosclerosis. However, little is known about the roles of histamine-specific receptors (HHRs) in arteriosclerosis. To define the roles of HHRs in arteriosclerosis, we investigated intimal remodeling in ligated carotid arteries of HHR-deficient mice (H1R(-/-) or H2R(-/-)). Quantitative analysis showed that H1R(-/-) mice had significantly less arteriosclerogenesis, whereas H2R(-/-) mice had more, as compared with WT mice. Bone marrow transplantation from H1R(-/-) or H2R(-/-) to WT mice confirmed the above observation. Furthermore, the increased expression of monocyte chemoattractant protein (MCP-1), platelet-derived growth factor (PDGF), adhesion molecules and liver X receptor (LXR)-related inflammatory signaling factors, including Toll-like receptor (TLR3), interleukin-1 receptor (IL-1R) and tumor necrosis factor receptor (TNF-R), was consistent with the arteriosclerotic phenotype of H2R(-/-) mice. Peripheral progenitor cells in H2R(-/-) mice accelerate ligation-induced arteriosclerosis through their regulation of MCP-1, PDGF, adhesion molecules and LXR-related inflammatory signaling factors. In contrast, peripheral progenitor cells act to suppress arteriosclerosis in H1R(-/-) mice, indicating that HHRs reciprocally regulate inflammation in the ligation-induced arteriosclerosis.

  10. P2X7 receptors induce degranulation in human mast cells.

    PubMed

    Wareham, Kathryn J; Seward, Elizabeth P

    2016-06-01

    Mast cells play important roles in host defence against pathogens, as well as being a key effector cell in diseases with an allergic basis such as asthma and an increasing list of other chronic inflammatory conditions. Mast cells initiate immune responses through the release of newly synthesised eicosanoids and the secretion of pre-formed mediators such as histamine which they store in specialised granules. Calcium plays a key role in regulating both the synthesis and secretion of mast-cell-derived mediators, with influx across the membrane, in particular, being necessary for degranulation. This raises the possibility that calcium influx through P2X receptors may lead to antigen-independent secretion of histamine and other granule-derived mediators from human mast cells. Here we show that activation of P2X7 receptors with both ATP and BzATP induces robust calcium rises in human mast cells and triggers their degranulation; both effects are blocked by the P2X7 antagonist AZ11645373, or the removal of calcium from the extracellular medium. Activation of P2X1 receptors with αβmeATP also induces calcium influx in human mast cells, which is significantly reduced by both PPADS and NF 449. P2X1 receptor activation, however, does not trigger degranulation. The results indicate that P2X7 receptors may play a significant role in contributing to the unwanted activation of mast cells in chronic inflammatory conditions where extracellular ATP levels are elevated.

  11. Oleoylethanolamide dose-dependently attenuates cocaine-induced behaviours through a PPARα receptor-independent mechanism.

    PubMed

    Bilbao, Ainhoa; Blanco, Eduardo; Luque-Rojas, María Jesús; Suárez, Juan; Palomino, Ana; Vida, Margarita; Araos, Pedro; Bermúdez-Silva, Francisco J; Fernández-Espejo, Emilio; Spanagel, Rainer; Rodríguez de Fonseca, Fernando

    2013-01-01

    Oleoylethanolamide (OEA) is an acylethanolamide that acts as an agonist of nuclear peroxisome proliferator-activated receptor alpha (PPARα) to exert their biological functions, which include the regulation of appetite and metabolism. Increasing evidence also suggests that OEA may participate in the control of reward-related behaviours. However, direct experimental evidence for the role of the OEA-PPARα receptor interaction in drug-mediated behaviours, such as cocaine-induced behavioural phenotypes, is lacking. The present study explored the role of OEA and its receptor PPARα on the psychomotor and rewarding responsiveness to cocaine using behavioural tests indicative of core components of addiction. We found that acute administration of OEA (1, 5 or 20 mg/kg, i.p.) reduced spontaneous locomotor activity and attenuated psychomotor activation induced by cocaine (20 mg/kg) in C57Bl/6 mice. However, PPARα receptor knockout mice showed normal sensitization, although OEA was capable of reducing behavioural sensitization with fewer efficacies. Furthermore, conditioned place preference and reinstatement to cocaine were intact in these mice. Our results indicate that PPARα receptor does not play a critical, if any, role in mediating short- and long-term psychomotor and rewarding responsiveness to cocaine. However, further research is needed for the identification of the targets of OEA for its inhibitory action on cocaine-mediated responses.

  12. Spinal vasopressin alleviates formalin-induced nociception by enhancing GABAA receptor function in mice.

    PubMed

    Peng, Fang; Qu, Zu-Wei; Qiu, Chun-Yu; Liao, Min; Hu, Wang-Ping

    2015-04-23

    Arginine vasopressin (AVP) plays a regulatory role in nociception. Intrathecal administration of AVP displays an antinociceptive effect. However, little is understood about the mechanism underlying spinal AVP analgesia. Here, we have found that spinal AVP dose dependently reduced the second, but not first, phase of formalin-induced spontaneous nociception in mice. The AVP analgesia was completely blocked by intrathecal injected SR 49059, a vasopressin-1A (V1A) receptor antagonist. However, spinal AVP failed to exert its antinociceptive effect on the second phase formalin-induced spontaneous nociception in V1A receptor knock-out (V1A-/-) mice. The AVP analgesia was also reversed by bicuculline, a GABAA receptor antagonist. Moreover, AVP potentiated GABA-activated currents in dorsal root ganglion neurons from wild-type littermates, but not from V1A-/- mice. Our results may reveal a novel spinal mechanism of AVP analgesia by enhancing the GABAA receptor function in the spinal cord through V1A receptors.

  13. P2X3 receptors induced inflammatory nociception modulated by TRPA1, 5-HT3 and 5-HT1A receptors.

    PubMed

    Krimon, Suzy; Araldi, Dionéia; do Prado, Filipe César; Tambeli, Cláudia Herrera; Oliveira-Fusaro, Maria Cláudia G; Parada, Carlos Amílcar

    2013-11-01

    It has been described that endogenous ATP via activation of P2X3 and P2X2/3 receptors contributes to inflammatory nociception in different models, including the formalin injected in subcutaneous tissue of the rat's hind paw. In this study, we have evaluated whether TRPA1, 5-HT3 and 5-HT1A receptors, whose activation is essential to formalin-induced inflammatory nociception, are involved in the nociception induced by activation of P2X3 receptors on subcutaneous tissue of the rat's hind paw. We have also evaluated whether the activation of P2X3 receptors increases the susceptibility of primary afferent neurons to formalin action modulated by activation of TRPA1, 5-HT3 or 5-HT1A receptors. Nociceptive response intensity was measured by observing the rat's behavior and considering the number of times the animal reflexively raised its hind paw (flinches) in 60min. Local subcutaneous administration of the selective TRPA1, 5-HT3 or 5-HT1A receptor antagonists HC 030031, tropisetron and WAY 100,135, respectively, prevented the nociceptive responses induced by the administration in the same site of the non-selective P2X3 receptor agonist αβmeATP. Administration of the selective P2X3 and P2X2/3 receptor antagonist A-317491 or pretreatment with oligonucleotides antisense against P2X3 receptor prevented the formalin-induced behavioral nociceptive responses during the first and second phases. Also, the co-administration of a subthreshold dose of αβmeATP with a subthreshold dose of formalin induced nociceptive behavior, which was prevented by local administration of tropisetron, HC 030031 or WAY 100, 135. These findings have demonstrated that the activation of P2X3 receptors induces inflammatory nociception modulated by TRPA1, 5-HT3 and 5-HT1A receptors. Also, they suggest that inflammatory nociception is modulated by the release of endogenous ATP and P2X3 receptor activation, which in turn, increases primary afferent nociceptor susceptibility to the action of inflammatory

  14. Chemical carcinogen-induced decreases in genomic 5-methyldeoxycytidine content of normal human bronchial epithelial cells

    SciTech Connect

    Wilson, V.L.; Smith, R.A.; Longoria, J.; Liotta, M.A.; Harper, C.M.; Harris, C.C.

    1987-05-01

    The genomic content of DNA 5-methyldeoxycytidine (m/sup 5/dC) was measured in dividing normal human bronchial epithelial cells treated with a broad range of chemical carcinogens. At noncytotoxic concentrations, all of the carcinogenic agents tested significantly reduced cellular DNA m/sup 5/dC content whereas the weakly carcinogenic and noncarcinogenic agents, benzo(e)pyrene and phenanthrene (respectively), did not. These reductions varied from 8% to 31% depending on the agent and the donor cells. The reduction is genomic m/sup 5/dC levels were concentration dependent for the carcinogenic polycyclic aromatic hydrocarbon benzo(a)pyrene. The authors speculate that carcinogen-induced perturbation of DNA m/sup 5/dC patterns may lead to heritable changes in gene expression and contribute to the molecular alterations involved in the initiation and the subsequent steps of the carcinogenesis process.

  15. Sulphur-containing compounds of durian activate the thermogenesis-inducing receptors TRPA1 and TRPV1.

    PubMed

    Terada, Yuko; Hosono, Takashi; Seki, Taiichiro; Ariga, Toyohiko; Ito, Sohei; Narukawa, Masataka; Watanabe, Tatsuo

    2014-08-15

    Durian (Durio zibethinus Murr.) is classified as a body-warming food in Indian herbalism, and its hyperthermic effect is empirically known in Southeast Asia. To investigate the mechanism underlying this effect, we focused on the thermogenesis-inducing receptors, TRPA1 and TRPV1. Durian contains sulphides similar to the TRPA1 and TRPV1 agonists of garlic. Accordingly, we hypothesized that the thermogenic effect of durian is driven by sulphide-induced TRP channel activation. To investigate our hypothesis, we measured the TRPA1 and TRPV1 activity of the sulphur-containing components of durian and quantified their content in durian pulp. These sulphur-containing components had a stronger effect on TRPA1 than TRPV1. Furthermore, sulphide content in the durian pulp was sufficient to evoke TRP channel activation and the main agonist was diethyl disulphide. From these results, we consider that the body-warming effect of durian is elicited by TRPA1 activation with its sulphides, as can be seen in spices.

  16. Method for individualized evaluation of antiemetic effect induced by 5-HT3 receptor antagonist.

    PubMed

    Nakamura, Hironori; Yokoyama, Haruko; Yoshimoto, Koichi; Nakajima, Akihiro; Okuyama, Kiyoshi; Iwase, Osamu; Yamada, Yasuhiko

    2013-01-01

    5-HT3 receptor antagonists are widely used for prevention of chemotherapy-induced nausea and vomiting, though their antiemetic effects vary among patients. We investigated a method for evaluation of antiemetic effects in individual patients. We used the 5-HT3 receptor occupancy of serotonin for our evaluation, which was estimated based on the plasma concentration of granisetron and concentration of serotonin near the 5-HT3 receptor in the small intestine, obtained by measuring the urinary concentrations of granisetron and 5-hydroxyindoleacetic acid (5-HIAA)/creatinine (Cre). The mean cumulative percent for urinary excretion of granisetron at 24 h after administration and coefficient of variation were 16.19 ± 6.30% and 38.91%, respectively. The time course of urinary concentration of 5-HIAA/Cre also varied among the patients. The value for 5-HT3 receptor occupancy of serotonin without granisetron was higher than that prior to administration (blank), thus most treated patients had the possibility of induced emesis. In contrast, that with granisetron was lower than the blank value, indicating that those treated patients would not develop emesis. Furthermore, the estimated 5-HT3 receptor occupancy of serotonin in the small intestine and actual individual patient condition corresponded well, showing the validity of our method. Our results suggest that it is possible to evaluate individual antiemetic effects by estimating the 5-HT3 receptor occupancy of serotonin in the small intestine based on plasma concentrations of granisetron and serotonin near the 5-HT3 receptor in the small intestine using noninvasive urine samples. This method of individual evaluation is considered to be useful and effective.

  17. SN79, a sigma receptor ligand, blocks methamphetamine-induced microglial activation and cytokine upregulation.

    PubMed

    Robson, Matthew J; Turner, Ryan C; Naser, Zachary J; McCurdy, Christopher R; Huber, Jason D; Matsumoto, Rae R

    2013-09-01

    Methamphetamine (METH) abuse is associated with several negative side effects including neurotoxicity in specific brain regions such as the striatum. The precise molecular mechanisms by which METH usage results in neurotoxicity remain to be fully elucidated, with recent evidence implicating the importance of microglial activation and neuroinflammation in damaged brain regions. METH interacts with sigma receptors which are found in glial cells in addition to neurons. Moreover, sigma receptor antagonists have been shown to block METH-induced neurotoxicity in rodents although the cellular mechanisms underlying their neuroprotection remain unknown. The purpose of the current study was to determine if the prototypic sigma receptor antagonist, SN79, mitigates METH-induced microglial activation and associated increases in cytokine expression in a rodent model of METH-induced neurotoxicity. METH increased striatal mRNA and protein levels of cluster of differentiation 68 (CD68), indicative of microglial activation. METH also increased ionized calcium binding adapter molecule 1 (IBA-1) protein expression, further confirming the activation of microglia. Along with microglial activation, METH increased striatal mRNA expression levels of IL-6 family pro-inflammatory cytokines, leukemia inhibitory factor (lif), oncostatin m (osm), and interleukin-6 (il-6). Pretreatment with SN79 reduced METH-induced increases in CD68 and IBA-1 expression, demonstrating its ability to prevent microglial activation. SN79 also attenuated METH-induced mRNA increases in IL-6 pro-inflammatory cytokine family members. The ability of a sigma receptor antagonist to block METH-induced microglial activation and cytokine production provides a novel mechanism through which the neurotoxic effects of METH may be mitigated.

  18. Prevention of Paclitaxel-Induced Neuropathy Through Activation of the Central Cannabinoid Type 2 Receptor System

    PubMed Central

    Naguib, Mohamed; Xu, Jijun J.; Diaz, Philippe; Brown, David L.; Cogdell, David; Bie, Bihua; Hu, Jianhua; Craig, Suzanne; Hittelman, Walter N.

    2012-01-01

    Background Peripheral neuropathy is a major dose-limiting toxicity of chemotherapy, especially after multiple courses of paclitaxel. The development of paclitaxel-induced neuropathy is associated with the activation of microglia followed by the activation and proliferation of astrocytes, and the expression and release of proinflammatory cytokines in the spinal dorsal horn. Cannabinoid type 2 (CB2) receptors are expressed in the microglia in neurodegenerative disease models. Methods To explore the potential of CB2 agonists for preventing paclitaxel-induced neuropathy, we designed and synthesized a novel CB2-selective agonist, namely MDA7. The effect of MDA7 in preventing paclitaxel-induced allodynia was assessed in rats and in CB2+/+ and CB2–/– mice. We hypothesize that the CB2 receptor functions in a negative-feedback loop and that early MDA7 administration can blunt the neuroinflammatory response to paclitaxel and prevent mechanical allodynia through interference with specific signaling pathways. Results We found that MDA7 prevents paclitaxel-induced mechanical allodynia in rats and mice in a dose- and time-dependent manner without compromising paclitaxel's antineoplastic effect. MDA7's neuroprotective effect was absent in CB2-/- mice and was blocked by CB2 antagonists, suggesting that MDA7's action directly involves CB2 receptor activation. MDA7 treatment was found to interfere with early events in the paclitaxel-induced neuroinflammatory response as evidenced by relatively reduced Toll-like receptor and CB2 expression in the lumbar spinal cord, reduced levels of extracellular signal regulated kinase 1/2 activity, reduced numbers of activated microglia and astrocytes, and reduced secretion of proinflammatory mediators in vivo and in in vitro models. Conclusions Our findings suggest an innovative therapeutic approach to prevent chemotherapy-induced neuropathy and may permit more aggressive use of active chemotherapeutic regimens with reduced long-term sequelae

  19. Basolateral amygdala CB1 cannabinoid receptors mediate nicotine-induced place preference.

    PubMed

    Hashemizadeh, Shiva; Sardari, Maryam; Rezayof, Ameneh

    2014-06-03

    In the present study, the effects of bilateral microinjections of cannabinoid CB1 receptor agonist and antagonist into the basolateral amygdala (intra-BLA) on nicotine-induced place preference were examined in rats. A conditioned place preference (CPP) apparatus was used for the assessment of rewarding effects of the drugs in adult male Wistar rats. Subcutaneous (s.c.) administration of nicotine (0.2mg/kg) induced a significant CPP, without any effect on the locomotor activity during the testing phase. Intra-BLA microinjection of a non-selective cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (0.1-0.5 μg/rat) with an ineffective dose of nicotine (0.1mg/kg, s.c.) induced a significant place preference. On the other hand, intra-BLA administration of AM251 (20-60 ng/rat), a selective cannabinoid CB1 receptor antagonist inhibited the acquisition of nicotine-induced place preference. It should be considered that the microinjection of the same doses of WIN 55,212-2 or AM251 into the BLA, by itself had no effect on the CPP score. The administration of a higher dose of AM251 (60 ng/rat) during the acquisition decreased the locomotor activity of animals on the testing phase. Interestingly, the microinjection of AM251 (20 and 40 ng/rat), but not WIN55,212-2 (0.1-0.5 μg/rat), into the BLA inhibited the expression of nicotine-induced place preference without any effect on the locomotor activity. Taken together, these findings support the possible role of endogenous cannabinoid system of the BLA in the acquisition and the expression of nicotine-induced place preference. Furthermore, it seems that there is a functional interaction between the BLA cannabinoid receptors and nicotine in producing the rewarding effects.

  20. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice.

    PubMed

    Michinaga, Shotaro; Nagase, Marina; Matsuyama, Emi; Yamanaka, Daisuke; Seno, Naoki; Fuka, Mayu; Yamamoto, Yui; Koyama, Yutaka

    2014-01-01

    Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs) are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice). Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV) administration of BQ788 (ETB antagonist), IRL-2500 (ETB antagonist), or FR139317 (ETA antagonist) prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.

  1. Differential Use of Human Neutrophil Fcγ Receptors for Inducing Neutrophil Extracellular Trap Formation.

    PubMed

    Alemán, Omar Rafael; Mora, Nancy; Cortes-Vieyra, Ricarda; Uribe-Querol, Eileen; Rosales, Carlos

    2016-01-01

    Neutrophils (PMN) are the most abundant leukocytes in the blood. PMN migrate from the circulation to sites of infection, where they are responsible for antimicrobial functions. PMN use phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes. NETs are fibers composed of chromatin and neutrophil-granule proteins. Several pathogens, including bacteria, fungi, and parasites, and also some pharmacological stimuli such as phorbol 12-myristate 13-acetate (PMA) are efficient inducers of NETs. Antigen-antibody complexes are also capable of inducing NET formation. However the particular Fcγ receptor involved in triggering this function is a matter of controversy. In order to provide some insight into what Fcγ receptor is responsible for NET formation, each of the two human Fcγ receptors was stimulated individually by specific monoclonal antibodies and NET formation was evaluated. FcγRIIa cross-linking did not promote NET formation. Cross-linking other receptors such as integrins also did not promote NET formation. In contrast FcγRIIIb cross-linking induced NET formation similarly to PMA stimulation. NET formation was dependent on NADPH-oxidase, PKC, and ERK activation. These data show that cross-linking FcγRIIIb is responsible for NET formation by the human neutrophil.

  2. ACTIVATION OF PPAR GAMMA RECEPTORS REDUCES LEVODOPA-INDUCED DYSKINESIAS IN 6-OHDA-LESIONED RATS

    PubMed Central

    Martinez, A. A.; Morgese, M. G.; Pisanu, A.; Macheda, T.; Paquette, M. A.; Seillier, A.; Cassano, T.; Carta, A.R.; Giuffrida, A.

    2014-01-01

    Long-term administration of L-3,4-dihydroxyphenylalanine (levodopa), the mainstay treatment for Parkinson’s disease (PD), is accompanied by fluctuations in its duration of action and motor complications (dyskinesia) that dramatically affect the quality of life of patients. Levodopa-induced dyskinesias (LID) can be modeled in rats with unilateral 6-OHDA lesions via chronic administration of levodopa, which causes increasingly severe axial, limb and oro-facial abnormal involuntary movements (AIMs) over time. In previous studies, we showed that direct activation of CB1 cannabinoid receptors alleviated rat AIMs. Interestingly, elevation of the endocannabinoid anandamide by URB597 (URB), an inhibitor of endocannabinoid catabolism, produced an anti-dyskinetic response that was only partially mediated via CB1 receptors and required the concomitant blockade of transient receptor potential vanilloid type-1 (TRPV1) channels by capsazepine (CPZ) [1]. In this study, we showed that stimulation of peroxisome proliferator-activated receptors (PPAR), a family of transcription factors activated by anandamide, contributes to the anti-dyskinetic effects of URB+CPZ, and that direct activation of the PPARγ subtype by rosiglitazone (RGZ) alleviates levodopa-induced AIMs in 6-OHDA rats. AIM reduction was associated with an attenuation of levodopa-induced increase of dynorphin, zif-268 and of ERK phosphorylation in the denervated striatum. RGZ treatment did not decrease striatal levodopa and dopamine bioavailability, nor did it affect levodopa antiparkinsonian activity. Collectively, these data indicate that PPARγ may represent a new pharmacological target for the treatment of LID. PMID:25486547

  3. Exchange factors directly activated by cAMP mediate melanocortin 4 receptor-induced gene expression

    PubMed Central

    Glas, Evi; Mückter, Harald; Gudermann, Thomas; Breit, Andreas

    2016-01-01

    Gs protein-coupled receptors regulate many vital body functions by activation of cAMP response elements (CRE) via cAMP-dependent kinase A (PKA)-mediated phosphorylation of the CRE binding protein (CREB). Melanocortin 4 receptors (MC4R) are prototypical Gs-coupled receptors that orchestrate the hypothalamic control of food-intake and metabolism. Remarkably, the significance of PKA for MC4R-induced CRE-dependent transcription in hypothalamic cells has not been rigorously interrogated yet. In two hypothalamic cell lines, we observed that blocking PKA activity had only weak or no effects on reporter gene expression. In contrast, inhibitors of exchange factors directly activated by cAMP-1/2 (EPAC-1/2) mitigated MC4R-induced CRE reporter activation and mRNA induction of the CREB-dependent genes c-fos and thyrotropin-releasing hormone. Furthermore, we provide first evidence that extracellular-regulated kinases-1/2 (ERK-1/2) activated by EPACs and not PKA are the elusive CREB kinases responsible for MC4R-induced CREB/CRE activation in hypothalamic cells. Overall, these data emphasize the pivotal role of EPACs rather than PKA in hypothalamic gene expression elicited by a prototypical Gs-coupled receptor. PMID:27612207

  4. A peroxovanadium compound induces Xenopus oocyte maturation: inhibition by a neutralizing anti-insulin receptor antibody.

    PubMed

    Cummings, C; Zhu, L; Sorisky, A; Liu, X J

    1996-05-01

    Synthetic peroxovanadium compounds are a new class of potent inhibitors of protein phosphotyrosine phosphatases. These compounds exhibit insulin-like activity both in vitro and in experimental animals. However, the molecular mechanism by which these compounds exert their biological effect is not well defined. We demonstrate here that several of these compounds induce Xenopus oocyte maturation in vitro, as indicated by germinal vesicle breakdown. Using one of these compounds for further studies, we show that the induction is dose-dependent and is accompanied by activation of maturation promoting factor as well as activation of Xenopus MAP kinase. Like insulin, bpV(pic) causes an acute accumulation of PI(3,4,5)P3 (phosphotidylinositol-3,4,5-trisphosphate), a product of PI 3-kinase. More importantly, bpV(pic)-induced oocyte maturation was abolished by microinjection of a neutralizing monoclonal anti-insulin receptor antibody (17A3) into oocytes or preincubation of oocytes with a PI 3-kinase inhibitor (wortmannin). These results suggest that bpV(pic) acts upstream of the Xenopus IGF-1 receptor in the induction of meiotic maturation, presumably by neutralizing an inhibitory protein tyrosine phosphatase(s) that may regulate the receptor. Finally, using an oocyte-follicle cell complex that responded to human chorionic gonadotropin (hCG) to undergo GVBD, we showed that injection of 17A3 anti-insulin receptor antibody into oocytes did not affect hCG-induced oocyte maturation.

  5. Differential Use of Human Neutrophil Fcγ Receptors for Inducing Neutrophil Extracellular Trap Formation

    PubMed Central

    Alemán, Omar Rafael; Mora, Nancy; Cortes-Vieyra, Ricarda; Uribe-Querol, Eileen; Rosales, Carlos

    2016-01-01

    Neutrophils (PMN) are the most abundant leukocytes in the blood. PMN migrate from the circulation to sites of infection, where they are responsible for antimicrobial functions. PMN use phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes. NETs are fibers composed of chromatin and neutrophil-granule proteins. Several pathogens, including bacteria, fungi, and parasites, and also some pharmacological stimuli such as phorbol 12-myristate 13-acetate (PMA) are efficient inducers of NETs. Antigen-antibody complexes are also capable of inducing NET formation. However the particular Fcγ receptor involved in triggering this function is a matter of controversy. In order to provide some insight into what Fcγ receptor is responsible for NET formation, each of the two human Fcγ receptors was stimulated individually by specific monoclonal antibodies and NET formation was evaluated. FcγRIIa cross-linking did not promote NET formation. Cross-linking other receptors such as integrins also did not promote NET formation. In contrast FcγRIIIb cross-linking induced NET formation similarly to PMA stimulation. NET formation was dependent on NADPH-oxidase, PKC, and ERK activation. These data show that cross-linking FcγRIIIb is responsible for NET formation by the human neutrophil. PMID:27034964

  6. A 5-HT(1B) receptor agonist inhibits light-induced suppression of pineal melatonin production.

    PubMed

    Rea, M A; Pickard, G E

    2000-03-10

    Serotonin (5-HT) modulates the phase adjusting effects of light on the mammalian circadian clock through the activation of presynaptic 5-HT(1B) receptors located on retinal terminals in the suprachiasmatic nucleus (SCN). The current study was conducted to determine whether activation of 5-HT(1B) receptors also alters photic regulation of nocturnal pineal melatonin production. Systemic administration of the 5-HT(1B) receptor agonist TFMPP attenuated the inhibitory effect of light on pineal melatonin synthesis in a dose-related manner with an apparent ED(50) value of 0.9 mg/kg. The effect of TFMPP on light-induced melatonin suppression was blocked by the 5-HT(1) receptor antagonist, methiothepin, but not by the 5-HT(1A) antagonist, WAY 100,635, consistent with the involvement of 5-HT(1B) receptors. The results are consistent with the interpretation that activation of presynaptic 5-HT(1B) receptors on retinal terminals in the SCN attenuates the effect of light on pineal melatonin production, as well as on circadian phase.

  7. The Mannose Receptor Is Involved in the Phagocytosis of Mycobacteria-Induced Apoptotic Cells

    PubMed Central

    2016-01-01

    Upon Mycobacterium tuberculosis infection, macrophages may undergo apoptosis, which has been considered an innate immune response. The pathways underlying the removal of dead cells in homeostatic apoptosis have been extensively studied, but little is known regarding how cells that undergo apoptotic death during mycobacterial infection are removed. This study shows that macrophages induced to undergo apoptosis with mycobacteria cell wall proteins are engulfed by J-774A.1 monocytic cells through the mannose receptor. This demonstration was achieved through assays in which phagocytosis was inhibited with a blocking anti-mannose receptor antibody and with mannose receptor competitor sugars. Moreover, elimination of the mannose receptor by a specific siRNA significantly diminished the expression of the mannose receptor and the phagocytosis of apoptotic cells. As shown by immunofluorescence, engulfed apoptotic bodies are initially located in Rab5-positive phagosomes, which mature to express the phagolysosome marker LAMP1. The phagocytosis of dead cells triggered an anti-inflammatory response with the production of TGF-β and IL-10 but not of the proinflammatory cytokines IL-12 and TNF-α. This study documents the previously unreported participation of the mannose receptor in the removal of apoptotic cells in the setting of tuberculosis (TB) infection. The results challenge the idea that apoptotic cell phagocytosis in TB has an immunogenic effect. PMID:27413759

  8. Octachlorostyrene induces cytochrome P450, UDP-glucuronosyltransferase, and sulfotransferase via the aryl hydrocarbon receptor and constitutive androstane receptor.

    PubMed

    Yanagiba, Yukie; Ito, Yuki; Kamijima, Michihiro; Gonzalez, Frank J; Nakajima, Tamie

    2009-09-01

    Octachlorostyrene (OCS) is a byproduct produced in the process of synthesis of chlorinated compounds. There are some reports concerning environmental contamination by OCS, but few on the toxicological effects on human. Drug-metabolizing enzymes may play an important role in toxicity through metabolic activation or deactivation of OCS. In this study, we investigated whether OCS influences these enzymes using wild-type and aryl hydrocarbon receptor (Ahr)-null mice; AhR regulates cytochrome P450 (CYP) 1A, UDP-glucuronosyltransferase (UGT), or sulfotransferase (SULT). Both mouse lines were treated with OCS (0, 32, and 64 mumol/kg) for 4 days by gavage. As a reference, the mice were treated with 20 mg/kg 3-methylcholanthrene (3MC) for 4 days. OCS treatment increased the expression of CYP 1A1 and CYP1A2 mRNA and ethoxyresorfin O-deethylase activity only in the wild-type mice, similar to that of the AhR activator 3MC. OCS treatment increased expression of UGT1A6 and SULT 1A1 mRNA and their associated enzyme activities only in Ahr-null mice, whereas 3MC still influenced these enzymes only in wild-type mice. OCS induced constitutive androstane receptor (CAR) only in Ahr-null mice, and the target gene CYP2B10 mRNA was induced more strongly in Ahr-null mice than in wild-type mice. 3MC slightly induced CYP2B10 mRNA only in the wild-type mice. These results suggest that CAR is involved in regulation of the UGT and SULT genes by OCS. Thus, OCS may regulate CYP1A via AhR, whereas it controls UGT1A6 and SULT1A via CAR.

  9. Determination of copper content in soils and ores by laser-induced breakdown spectrometry

    NASA Astrophysics Data System (ADS)

    Labutin, T. A.; Popov, A. M.; Zaytsev, S. M.; Cal'ko, I. A.; Zorov, N. B.

    2016-09-01

    It is demonstrated that the method of laser-induced breakdown spectrometry can be applied for quantitative determination of the copper content at a level of 500-40000 g/t, typical for copper ores and soil in the outcrop areas. To avoid the self-absorption of the resonance copper lines, we studied the most intense nonresonant lines of copper atoms and ions. It is shown that the Cu I 521.82-nm line is rather intense and provides the linear calibration. The copper detection limit for this line of 280 g/t allows its use for rapid mapping of outcrop areas.

  10. The Unique Dopamine/Ecdysteroid Receptor Modulates Ethanol-Induced Sedation in Drosophila

    PubMed Central

    Petruccelli, Emily; Li, Qi; Rao, Yi

    2016-01-01

    Steroids profoundly influence behavioral responses to alcohol by activating canonical nuclear hormone receptors and exerting allosteric effects on ion channels. Accumulating evidence has demonstrated that steroids can also trigger biological effects by directly binding G-protein-coupled receptors (GPCRs), yet physiological roles of such unconventional steroid signaling in controlling alcohol-induced behaviors remain unclear. The dopamine/ecdysteroid receptor (DopEcR) is a GPCR that mediates nongenomic actions of ecdysteroids, the major steroid hormones in insects. Here, we report that Drosophila DopEcR plays a critical role in ethanol-induced sedation. DopEcR mutants took longer than control flies to become sedated during exposure to ethanol, despite having normal ethanol absorption or metabolism. RNAi-mediated knockdown of DopEcR expression revealed that this receptor is necessary after eclosion, and is required in particular neuronal subsets, including cholinergic and peptidergic neurons, to mediate this behavior. Additionally, flies ubiquitously overexpressing DopEcR cDNA had a tendency to become sedated quickly upon ethanol exposure. These results indicate that neuronal subset-specific expression of DopEcR in adults is required for normal sedation upon exposure to ethanol. We also obtained evidence indicating that DopEcR may promote ethanol sedation by suppressing epidermal growth factor receptor/extracellular signal-regulated kinase signaling. Last, genetic and pharmacological analyses suggested that in adult flies ecdysone may serve as an inverse agonist of DopEcR and suppress the sedation-promoting activity of DopEcR in the context of ethanol exposure. Our findings provide the first evidence for the involvement of nongenomic G-protein-coupled steroid receptors in the response to alcohol, and shed new light on the potential roles of steroids in alcohol-use disorders. SIGNIFICANCE STATEMENT Alcohol abuse is an alarming personal and societal burden. The

  11. GABAB receptor stimulation decreases amphetamine-induced behavior and neuropeptide gene expression in the striatum.

    PubMed

    Zhou, Wenxia; Mailloux, Adam W; Jung, Bruce J; Edmunds, Hayward S; McGinty, Jacqueline F

    2004-04-09

    The purpose of this study was to investigate whether GABA(B) receptor activation blocks acute amphetamine-induced behavioral activity, dopamine release, and neuropeptide mRNA expression in the striatum. Systemic administration of R-(+)-baclofen (1.25 mg/kg, i.p.) did not alter total distance traveled or vertical rearing induced by amphetamine (2.5 mg/kg, i.p.). At 2.5 mg/kg, baclofen did not alter spontaneous motor activity or total distance traveled, but completely blocked vertical rearing induced by amphetamine. At 5.0 mg/kg, baclofen completely blocked both total distance traveled and vertical rearing induced by amphetamine. Quantitative in situ hybridization histochemistry revealed that baclofen (2.5 mg/kg, i.p.) decreased the ability of amphetamine to increase preprodynorphin (PPD), preprotachykinin (PPT), preproenkephalin (PPE), and secretogranin II (SGII) mRNA levels in the striatum without altering the basal levels of these signals. Baclofen also blocked the amphetamine-induced rise in SGII mRNA in the core and shell of the nucleus accumbens and cingulate cortex. In a separate experiment, systemic baclofen (2.5 mg/kg) decreased the amphetamine-induced increase in dialysate dopamine levels in the striatum. These results suggest that reduced striatal dopamine release contributes to the ability of GABA(B) receptor activation to decrease acute amphetamine-induced behavioral activity and striatal neuropeptide gene expression.

  12. Cardiac-Specific Knockout of ETA Receptor Mitigates Paraquat-Induced Cardiac Contractile Dysfunction.

    PubMed

    Wang, Jiaxing; Lu, Songhe; Zheng, Qijun; Hu, Nan; Yu, Wenjun; Li, Na; Liu, Min; Gao, Beilei; Zhang, Guoyong; Zhang, Yingmei; Wang, Haichang

    2016-07-01

    Paraquat (1,1'-dim ethyl-4-4'-bipyridinium dichloride), a highly toxic quaternary ammonium herbicide widely used in agriculture, exerts potent toxic prooxidant effects resulting in multi-organ failure including the lung and heart although the underlying mechanism remains elusive. Recent evidence suggests possible involvement of endothelin system in paraquat-induced acute lung injury. This study was designed to examine the role of endothelin receptor A (ETA) in paraquat-induced cardiac contractile and mitochondrial injury. Wild-type (WT) and cardiac-specific ETA receptor knockout mice were challenged to paraquat (45 mg/kg, i.p.) for 48 h prior to the assessment of echocardiographic, cardiomyocyte contractile and intracellular Ca(2+) properties, as well as apoptosis and mitochondrial damage. Levels of the mitochondrial proteins for biogenesis and oxidative phosphorylation including UCP2, HSP90 and PGC1α were evaluated. Our results revealed that paraquat elicited cardiac enlargement, mechanical anomalies including compromised echocardiographic parameters (elevated left ventricular end-systolic and end-diastolic diameters as well as reduced factional shortening), suppressed cardiomyocyte contractile function, intracellular Ca(2+) handling, overt apoptosis and mitochondrial damage. ETA receptor knockout itself failed to affect myocardial function, apoptosis, mitochondrial integrity and mitochondrial protein expression. However, ETA receptor knockout ablated or significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) defect, apoptosis and mitochondrial damage. Taken together, these findings revealed that endothelin system in particular the ETA receptor may be involved in paraquat-induced toxic myocardial contractile anomalies possibly related to apoptosis and mitochondrial damage.

  13. AMPA receptor pHluorin-GluA2 reports NMDA receptor-induced intracellular acidification in hippocampal neurons.

    PubMed

    Rathje, Mette; Fang, Huaqiang; Bachman, Julia L; Anggono, Victor; Gether, Ulrik; Huganir, Richard L; Madsen, Kenneth L

    2013-08-27

    NMDA receptor activation promotes endocytosis of AMPA receptors, which is an important mechanism underlying long-term synaptic depression. The pH-sensitive GFP variant pHluorin fused to the N terminus of GluA2 (pH-GluA2) has been used to assay NMDA-mediated AMPA receptor endocytosis and recycling. Here, we demonstrate that in somatic and dendritic regions of hippocampal neurons a large fraction of the fluorescent signal originates from intracellular pH-GluA2, and that the decline in fluorescence in response to NMDA and AMPA primarily describes an intracellular acidification, which quenches the pHluorin signal from intracellular receptor pools. Neurons expressing an endoplasmic reticulum-retained mutant of GluA2 (pH-GluA2 ΔC49) displayed a larger response to NMDA than neurons expressing wild-type pH-GluA2. A similar NMDA-elicited decline in pHluorin signal was observed by expressing cytosolic pHluorin alone without fusion to GluA2 (cyto-pHluorin). Intracellular acidification in response to NMDA was further confirmed by using the ratiometric pH indicator carboxy-SNARF-1. The NMDA-induced decline was followed by rapid recovery of the fluorescent signal from both cyto-pHluorin and pH-GluA2. The recovery was sodium-dependent and sensitive to Na(+)/H(+)-exchanger (NHE) inhibitors. Moreover, recovery was more rapid after shRNA-mediated knockdown of the GluA2 binding PDZ domain-containing protein interacting with C kinase 1 (PICK1). Interestingly, the accelerating effect of PICK1 knockdown on the fluorescence recovery was eliminated in the presence of the NHE1 inhibitor zoniporide. Our results indicate that the pH-GluA2 recycling assay is an unreliable assay for studying AMPA receptor trafficking and also suggest a role for PICK1 in regulating intracellular pH via modulation of NHE activity.

  14. Thyroid iodine content measured by x-ray fluorescence in amiodarone-induced thyrotoxicosis: concise communication

    SciTech Connect

    Leger, A.F.; Fragu, P.; Rougier, P.; Laurent, M.F.; Tubiana, M.; Savole, J.C.

    1983-07-01

    Iodine-induced thyrotoxicosis (IiT) is characterized by (a) a low radioiodine uptake, increased by exogenous TSH, and (b) a spontaneous evolution towards cure within a few months. An hypothetical pathogenesis of IiT is an initial inflation in the stores of thyroid hormones during iodine excess, followed by their sudden discharge into the circulation. Thyroid iodine content was measured by fluorescent scanning in 10 patients with amiodarone-induced thyrotoxicosis and in various control groups. Results were found to be high at the onset of the disease and to decrease during its course. The data agree with the hypothetical pathogenesis. Furthermore they may permit exclusion of a painless subacute thyroiditis, which is the main differential diagnosis of IiT.

  15. Cannabinoid CB1 receptor mediates glucocorticoid effects on hormone secretion induced by volume and osmotic changes.

    PubMed

    Ruginsk, S G; Uchoa, E T; Elias, L L K; Antunes-Rodrigues, J

    2012-02-01

    The present study provides the first in vivo evidence that the cannabinoid CB(1) receptor mediates the effects of dexamethasone on hormone release induced by changes in circulating volume and osmolality. Male adult rats were administered with the CB(1) receptor antagonist rimonabant (10 mg/Kg, p.o.), followed or not in 1 hour by dexamethasone (1 mg/Kg, i.p.). Extracellular volume expansion (EVE, 2 mL/100 g of body weight, i.v.) was performed 2 hours after dexamethasone or vehicle treatment using either isotonic (I-EVE, 0.15 mol/L) or hypertonic (H-EVE, 0.30 mol/L) NaCl solution. Five minutes after EVE, animals were decapitated and trunk blood was collected for all plasma measurements. Rimonabant potentiated oxytocin (OT) secretion induced by H-EVE and completely reversed the inhibitory effects of dexamethasone in response to the same stimulus. These data suggest that glucocorticoid modulation of OT release is mediated by the CB(1) receptor. Although dexamethasone did not affect vasopressin (AVP) secretion induced by H-EVE, the administration of rimonabant potentiated AVP release in response to the same stimulus, supporting the hypothesis that the CB(1) receptor regulates AVP secretion independently of glucocorticoid-mediated signalling. Dexamethasone alone did not affect atrial natriuretic peptide (ANP) release stimulated by I-EVE or H-EVE. However, pretreatment with rimonabant potentiated ANP secretion induced by H-EVE, suggesting a possible role for the CB(1) receptor in the control of peripheral factors that modulate cardiovascular function. Rimonabant also reversed the inhibitory effects of dexamethasone on H-EVE-induced corticosterone secretion, reinforcing the hypothesis that the CB(1) receptor may be involved in the negative feedback exerted by glucocorticoids on the activity of the hypothalamic-pituitary-adrenal axis. Collectively, the results of the present study indicate that the CB(1) receptor modulates neurohypophyseal hormone secretion and

  16. Effect of dopamine and serotonin receptor antagonists on fencamfamine-induced abolition of latent inhibition.

    PubMed

    de Aguiar, Cilene Rejane Ramos Alves; de Aguiar, Marlison José Lima; DeLucia, Roberto; Silva, Maria Teresa Araujo

    2013-01-05

    The purpose of this investigation was to verify the role of dopamine and serotonin receptors in the effect of fencamfamine (FCF) on latent inhibition. FCF is a psychomotor stimulant with an indirect dopaminergic action. Latent inhibition is a model of attention. Latent inhibition is blocked by dopaminergic agents and facilitated by dopamine receptor agonists. FCF has been shown to abolish latent inhibition. The serotonergic system may also participate in the neurochemical mediation of latent inhibition. The selective dopamine D(1) receptor antagonist SCH 23390 (7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol), D(2) receptor antagonists pimozide (PIM) and methoclopramide (METH), and serotonin 5-HT(2A/C) receptor antagonist ritanserin (RIT) were used in the present study. Latent inhibition was evaluated using a conditioned emotional response procedure. Male Wistar rats that were water-restricted were subjected to a three-phase procedure: preexposure to a tone, tone-shock conditioning, and a test of the effect of the tone on licking frequency. All of the drugs were administered before the preexposure and conditioning phases. The results showed that FCF abolished latent inhibition, and this effect was clearly antagonized by PIM and METH and moderately attenuated by SCH 23390. At the doses used in the present study, RIT pretreatment did not affect latent inhibition and did not eliminate the effect of FCF, suggesting that the FCF-induced abolition of latent inhibition is not mediated by serotonin 5-HT(2A/C) receptors. These results suggest that the effect of FCF on latent inhibition is predominantly related to dopamine D(2) receptors and that dopamine D(2) receptors participate in attention processes.

  17. The aryl hydrocarbon receptor mediates raloxifene-induced apoptosis in estrogen receptor-negative hepatoma and breast cancer cells

    PubMed Central

    O'Donnell, E F; Koch, D C; Bisson, W H; Jang, H S; Kolluri, S K

    2014-01-01

    Identification of new molecular targets for the treatment of breast cancer is an important clinical goal, especially for triple-negative breast cancer, which is refractory to existing targeted treatments. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known primarily as the mediator of dioxin toxicity. However, the AhR can also inhibit cellular proliferation in a ligand-dependent manner and act as a tumor suppressor in mice, and thus may be a potential anticancer target. To investigate the AhR as an anticancer target, we conducted a small molecule screen to discover novel AhR ligands with anticancer properties. We identified raloxifene, a selective estrogen receptor (ER) modulator currently used in the clinic for prevention of ER-positive breast cancer and osteoporosis in post-menopausal women, as an AhR activator. Raloxifene directly bound the AhR and induced apoptosis in ER-negative mouse and human hepatoma cells in an AhR-dependent manner, indicating that the AhR is a molecular target of raloxifene and mediates raloxifene-induced apoptosis in the absence of ER. Raloxifene selectively induced apoptosis of triple-negative MDA-MB-231 breast cancer cells compared with non-transformed mammary epithelial cells via the AhR. Combined with recent data showing that raloxifene inhibits triple-negative breast cancer xenografts in vivo (Int J Oncol. 43(3):785-92, 2013), our results support the possibility of repurposing of raloxifene as an AhR-targeted therapeutic for triple-negative breast cancer patients. To this end, we also evaluated the role of AhR expression on survival of patients diagnosed with breast cancer. We found that higher expression of the AhR is significantly associated with increased overall survival and distant metastasis-free survival in both hormone-dependent (ER-positive) and hormone-independent (ER and progesterone receptor (PR)-negative) breast cancers. Together, our data strongly support the possibility of using the Ah

  18. The aryl hydrocarbon receptor mediates raloxifene-induced apoptosis in estrogen receptor-negative hepatoma and breast cancer cells.

    PubMed

    O'Donnell, E F; Koch, D C; Bisson, W H; Jang, H S; Kolluri, S K

    2014-01-30

    Identification of new molecular targets for the treatment of breast cancer is an important clinical goal, especially for triple-negative breast cancer, which is refractory to existing targeted treatments. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known primarily as the mediator of dioxin toxicity. However, the AhR can also inhibit cellular proliferation in a ligand-dependent manner and act as a tumor suppressor in mice, and thus may be a potential anticancer target. To investigate the AhR as an anticancer target, we conducted a small molecule screen to discover novel AhR ligands with anticancer properties. We identified raloxifene, a selective estrogen receptor (ER) modulator currently used in the clinic for prevention of ER-positive breast cancer and osteoporosis in post-menopausal women, as an AhR activator. Raloxifene directly bound the AhR and induced apoptosis in ER-negative mouse and human hepatoma cells in an AhR-dependent manner, indicating that the AhR is a molecular target of raloxifene and mediates raloxifene-induced apoptosis in the absence of ER. Raloxifene selectively induced apoptosis of triple-negative MDA-MB-231 breast cancer cells compared with non-transformed mammary epithelial cells via the AhR. Combined with recent data showing that raloxifene inhibits triple-negative breast cancer xenografts in vivo (Int J Oncol. 43(3):785-92, 2013), our results support the possibility of repurposing of raloxifene as an AhR-targeted therapeutic for triple-negative breast cancer patients. To this end, we also evaluated the role of AhR expression on survival of patients diagnosed with breast cancer. We found that higher expression of the AhR is significantly associated with increased overall survival and distant metastasis-free survival in both hormone-dependent (ER-positive) and hormone-independent (ER and progesterone receptor (PR)-negative) breast cancers. Together, our data strongly support the possibility of using the Ah

  19. The thrombin receptor extracellular domain contains sites crucial for peptide ligand-induced activation.

    PubMed Central

    Bahou, W F; Coller, B S; Potter, C L; Norton, K J; Kutok, J L; Goligorsky, M S

    1993-01-01

    A thrombin receptor (TR) demonstrating a unique activation mechanism has recently been isolated from a megakaryocytic (Dami) cell line. To further study determinants of peptide ligand-mediated activation phenomenon, we have isolated, cloned, and stably expressed the identical receptor from a human umbilical vein endothelial cell (HUVEC) library. Chinese hamster ovary (CHO) cells expressing a functional TR (CHO-TR), platelets, and HUVECs were then used to specifically characterize alpha-thrombin- and peptide ligand-induced activation responses using two different antibodies: anti-TR34-52 directed against a 20-amino acid peptide spanning the thrombin cleavage site, and anti-TR1-160 generated against the NH2-terminal 160 amino acids of the TR expressed as a chimeric protein in Escherichia coli. Activation-dependent responses to both alpha-thrombin (10 nM) and peptide ligand (20 microM) were studied using fura 2-loaded cells and microspectrofluorimetry. Whereas preincubation of CHO-TR with anti-TR34-52 abolished only alpha-thrombin-induced [Ca2+]i transients, preincubation with anti-TR1-160 abrogated both alpha-thrombin- and peptide ligand-induced responses. This latter inhibitory effect was dose dependent and similar for both agonists, with an EC50 of approximately 90 micrograms/ml. Anti-TR1-160 similarly abolished peptide ligand-induced [Ca2+]i transients in platelets and HUVECs, whereas qualitatively different responses characterized by delayed but sustained elevations in [Ca2+]i transients were evident using alpha-thrombin. Platelet aggregation to low concentrations of both ligands was nearly abolished by anti-TR1-160, although some shape change remained; anti-TR34-52 only inhibited alpha-thrombin-induced aggregation. These data establish that a critical recognition sequence for peptide ligand-mediated receptor activation is contained on the NH2-terminal portion of the receptor, upstream from the first transmembrane domain. Furthermore, alpha-thrombin-induced

  20. Receptor expression is essential for proliferation induced by dimerized Jak kinases

    SciTech Connect

    Fujii, Hodaka

    2008-06-13

    Two members of Jak kinases, Jak1 and Jak3, are associated with the cytoplasmic domains of the interleukin-2 (IL-2) receptor (IL-2R) {beta} chain (IL-2R{beta}) and the common cytokine receptor {gamma} chain ({gamma}c), respectively, and accumulating evidence indicates their functional importance in IL-2 signaling. Here, I showed that coumermycin-induced chemical heterodimerization of Jak1 and Jak3 but not homodimerization of Jak1 or Jak3 induces cell proliferation of an IL-2R-reconstituted cell line. In this regard, expression of IL-2R{beta} was essential for cell proliferation by chemical heterodimerization of Jak1 and Jak3, indicating that dimerized Jak1 and Jak3 induce heterodimerization of IL-2R{beta} and {gamma}c, which may activate receptor-bound signaling molecules. Previous reports using chemical dimerization suggest that dimerization of Jak kinases is sufficient to induce cell proliferation. The present study indicates that re-evaluation of this conclusion is necessary and that interpretation of functional analysis of signaling molecules using chemical dimerizers needs more careful assessment.

  1. Highly inducible expression from vectors containing multiple GRE's in CHO cells overexpressing the glucocorticoid receptor.

    PubMed Central

    Israel, D I; Kaufman, R J

    1989-01-01

    A conditional glucocorticoid-responsive expression vector system is described for highly inducible expression of heterologous genes in mammalian cells. This host-vector system requires high level expression of the glucocorticoid receptor (GR) protein in the host cell and multiple copies of the receptor binding site within the expression vector. Transfection and selection of Chinese hamster ovary cells with expression vectors encoding the rat GR yielded cell lines which express functional receptor at high levels. Insertion of multiple copies of the MMTV enhancer (glucocorticoid responsive element, GRE) into an Adenovirus major late promoter (AdMLP) based expression vector yielded greater than 1000-fold inducible expression by dexamethasone (dex) in transient DNA transfection assays. The induced expression level was 7-fold greater than that obtained with an AdMLP based vector containing an SV40 enhancer, but lacking GRE's. Vectors containing the SV40 enhancer in combination with multiple GRE's exhibited elevated basal expression in the absence of dex, but retained inducibility in both transient assays and after integration and amplification in the CHO genome. This expression system should be of general utility for studying gene regulation and for expressing heterologous genes in a regulatable fashion. Images PMID:2546123

  2. Channel opening by anesthetics and GABA induces similar changes in the GABAA receptor M2 segment.

    PubMed

    Rosen, Ayelet; Bali, Moez; Horenstein, Jeffrey; Akabas, Myles H

    2007-05-01

    For many general anesthetics, their molecular basis of action involves interactions with GABA(A) receptors. Anesthetics produce concentration-dependent effects on GABA(A) receptors. Low concentrations potentiate submaximal GABA-induced currents. Higher concentrations directly activate the receptors. Functional effects of anesthetics have been characterized, but little is known about the conformational changes they induce. We probed anesthetic-induced conformational changes in the M2 membrane-spanning, channel-lining segment using disulfide trapping between engineered cysteines. Previously, we showed that oxidation by copper phenanthroline in the presence of GABA of the M2 6' cysteine mutants, alpha(1)T261Cbeta(1)T256C and alpha(1)beta(1)T256C resulted in formation of an intersubunit disulfide bond between the adjacent beta-subunits that significantly increased the channels' spontaneous open probability. Oxidation in GABA's absence had no effect. We examined the effect on alpha(1)T261Cbeta(1)T256C and on alpha(1)beta(1)T256C of oxidation by copper phenanthroline in the presence of potentiating and directly activating concentrations of the general anesthetics propofol, pentobarbital, and isoflurane. Oxidation in the presence of potentiating concentration of anesthetics had little effect. Oxidation in the presence of directly activating anesthetic concentrations significantly increased the channels' spontaneous open probability. We infer that activation by anesthetics and GABA induces a similar conformational change at the M2 segment 6' position that is related to channel opening.

  3. Studies on the role of the Ah receptor in hexachloro-benzene-induced porphyria

    SciTech Connect

    Hahn, M.E.

    1987-01-01

    Many of the effects of hexachlorobenzene (HCB) resemble those of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), whose effects are initiated by its binding to the AH receptor, the regulatory gene product of the Ah locus. I investigated the ability of HCB to interact with the AH receptor and the involvement of this protein in HCB-induced porphyria. The induction of two cytochrome P450 isozymes regulated by the Ah locus was also examined in light of their possible role in the pathogenesis of HCB- and TCDD-induced porphyria. HCB competitively inhibited the in vitro specific binding of ({sup 3}H)-TCDD to the rat hepatic Ah receptor (K{sub I} = 2.1 {mu}M) without affecting the solubility of ({sup 3}H)TCDD. Following the administration of HCB to rats, the number of ({sup 3}H)TCDD specific binding sites was reduced by up to 40%. HCB induced cytochromes P450b, P450e, P450c, and P450d, confirming that it is a mixed-type P450 inducer. The presence of porphyria in mice was assessed by measuring urinary and hepatic porphyrins and hepatic uroporphyrinogen decarboxylase activity.

  4. The mitochondrial and death receptor pathways involved in the thymocytes apoptosis induced by aflatoxin B1

    PubMed Central

    Chi, Xiaofeng; Li, Xiaochong; Jiang, Min; Fang, Jing; Cui, Hengmin; Lai, Weimin; Zhou, Yi; Zhou, Shan

    2016-01-01

    Aflatoxin B1 (AFB1) is a potent immunosuppressive agent in endotherms, which can be related to the up-regulated apoptosis of immune organs. In this study, we investigated the roles of the mitochondrial, death receptor, and endoplasmic reticulum pathways in Aflatoxin B1 induced thymocytes apoptosis. Chickens were fed an aflatoxin B1 containing diet (0.6 mg/kg AFB1) for 3 weeks. Our results showed that (1) AFB1 diet induced the decrease of T-cell subsets, morphological changes, and excessive apoptosis of thymus. (2) The excessive apoptosis involved the mitochondrial pathway (up-regulation of Bax, Bak, cytC and down-regulation of Bcl-2 and Bcl-xL) and death receptor pathway (up-regulation of FasL, Fas and FADD). (3) Oxidative stress, an apoptosis inducer, was confirmed in the thymus. In conclusion, this is the first study to demonstrate that mitochondrial and death receptor pathways involved in AFB1 induced thymocytes apoptosis in broilers. PMID:26933817

  5. Activation of NR2A receptors induces ischemic tolerance through CREB signaling.

    PubMed

    Terasaki, Yasukazu; Sasaki, Tsutomu; Yagita, Yoshiki; Okazaki, Shuhei; Sugiyama, Yukio; Oyama, Naoki; Omura-Matsuoka, Emi; Sakoda, Saburo; Kitagawa, Kazuo

    2010-08-01

    Previous exposure to a nonlethal ischemic insult protects the brain against subsequent harmful ischemia. N-methyl-D-aspartate (NMDA) receptors are a highly studied target of neuroprotection after ischemia. Recently, NMDA receptor subtypes were implicated in neuronal survival and death. We focused on the contribution of NR2A and cyclic-AMP response element (CRE)-binding protein (CREB) signaling to ischemic tolerance using primary cortical neurons. Ischemia in vitro was modeled by oxygen-glucose deprivation (OGD). Ischemic tolerance was induced by applying 45-mins OGD 24 h before 180-mins OGD. Sublethal OGD also induced cross-tolerance against lethal glutamate and hydrogen peroxide. After sublethal OGD, expression of phosphorylated CREB and CRE transcriptional activity were significantly increased. When CRE activity was inhibited by CREB-S133A, a mutant CREB, ischemic tolerance was abolished. Inhibiting NR2A using NVP-AAM077 attenuated preconditioning-induced neuroprotection and correlated with decreased CRE activity levels. Activating NR2A using bicuculline and 4-aminopiridine induced resistance to lethal ischemia accompanied by elevated CRE activity levels, and this effect was abolished by NVP-AAM077. Elevated brain-derived neurotrophic factor (BDNF) transcriptional activities were observed after sublethal OGD and administration of bicuculline and 4-aminopiridine. NR2A-containing NMDA receptors and CREB signaling have important functions in the induction of ischemic tolerance. This may provide potential novel therapeutic strategies to treat ischemic stroke.

  6. An antibody blocking activin type II receptors induces strong skeletal muscle hypertrophy and protects from atrophy.

    PubMed

    Lach-Trifilieff, Estelle; Minetti, Giulia C; Sheppard, KellyAnn; Ibebunjo, Chikwendu; Feige, Jerome N; Hartmann, Steffen; Brachat, Sophie; Rivet, Helene; Koelbing, Claudia; Morvan, Frederic; Hatakeyama, Shinji; Glass, David J

    2014-02-01

    The myostatin/activin type II receptor (ActRII) pathway has been identified to be critical in regulating skeletal muscle size. Several other ligands, including GDF11 and the activins, signal through this pathway, suggesting that the ActRII receptors are major regulatory nodes in the regulation of muscle mass. We have developed a novel, human anti-ActRII antibody (bimagrumab, or BYM338) to prevent binding of ligands to the receptors and thus inhibit downstream signaling. BYM338 enhances differentiation of primary human skeletal myoblasts and counteracts the inhibition of differentiation induced by myostatin or activin A. BYM338 prevents myostatin- or activin A-induced atrophy through inhibition of Smad2/3 phosphorylation, thus sparing the myosin heavy chain from degradation. BYM338 dramatically increases skeletal muscle mass in mice, beyond sole inhibition of myostatin, detected by comparing the antibody with a myostatin inhibitor. A mouse version of the antibody induces enhanced muscle hypertrophy in myostatin mutant mice, further confirming a beneficial effect on muscle growth beyond myostatin inhibition alone through blockade of ActRII ligands. BYM338 protects muscles from glucocorticoid-induced atrophy and weakness via prevention of muscle and tetanic force losses. These data highlight the compelling therapeutic potential of BYM338 for the treatment of skeletal muscle atrophy and weakness in multiple settings.

  7. Berberine induces GLP-1 secretion through activation of bitter taste receptor pathways.

    PubMed

    Yu, Yunli; Hao, Gang; Zhang, Quanying; Hua, Wenyan; Wang, Meng; Zhou, Wenjia; Zong, Shunlin; Huang, Ming; Wen, Xiaozhou

    2015-09-15

    Our previous studies revealed that berberine-mediated GLP-1 secretion was a possible mechanism for berberine exerting good effects on hyperglycemia. This study was designed to ascertain whether berberine-induced secretion of GLP-1 was related with activation of bitter taste receptors expressed in gastrointestinal tract. Western blotting results showed that TAS2R38, a subtype of bitter taste receptor, was expressed on human enteroendocrine NCI-H716 cells. GLP-1 secretion induced by berberine from NCI-H716 cells was inhibited by incubation with anti-TAS2R38 antibody. We further performed gene silencing using siRNA to knockdown TAS2R38 from NCI-H716 cells, which showed that siRNA knockdown of the TAS2R38 reduced berberine-mediated GLP-1 secretion. We adopted inhibitors of PLC and TRPM5 known to be involved in bitter taste transduction to investigate the underlying pathways mediated in berberine-induced GLP-1 secretion. It was found that PLC inhibitor U73122 inhibited berberine-induced GLP-1 release in NCI-H716 cells, while TRPM5 blocker quinine failed to attenuate berberine-induced secretion of GLP-1. The present results demonstrated that berberine stimulated GLP-1 secretion via activation of gut-expressed bitter taste receptors in a PLC-dependent manner. Because berberine was found to be a ligand of bitter taste receptor, the results of present study may provide an explanation for some bitter taste substance obtain hypoglycemic effect.

  8. CARMA3 deficiency abrogates G protein-coupled receptor-induced NF-κB activation

    PubMed Central

    Grabiner, Brian C.; Blonska, Marzenna; Lin, Pei-Chun; You, Yun; Wang, Donghai; Sun, Jiyuan; Darnay, Bryant G.; Dong, Chen; Lin, Xin

    2007-01-01

    G protein-coupled receptors (GPCRs) play pivotal roles in regulating various cellular functions. Although many GPCRs induce NF-κB activation, the molecular mechanism of GPCR-induced NF-κB activation remains largely unknown. CARMA3 (CARD and MAGUK domain-containing protein 3) is a scaffold molecule with unknown biological functions. By generating CARMA3 knockout mice using the gene targeting approach, here we show CARMA3 is required for GPCR-induced NF-κB activation. Mechanistically, we found that CARMA3 deficiency impairs GPCR-induced IκB kinase (IKK) activation, although it does not affect GPCR-induced IKKα/β phosphorylation, indicating that inducible phosphorylation of IKKα/β alone is not sufficient to induce its kinase activity. We also found that CARMA3 is physically associated with NEMO/IKKγ, and induces polyubiquitination of an unknown protein(s) that associates with NEMO, likely by linking NEMO to TRAF6. Consistently, we found TRAF6 deficiency also abrogates GPCR-induced NF-κB activation. Together, our results provide the genetic evidence that CARMA3 is required for GPCR-induced NF-κB activation. PMID:17438001

  9. Lack of neuroprotection in the absence of P2X7 receptors in toxin-induced animal models of Parkinson's disease

    PubMed Central

    2011-01-01

    Background Previous studies indicate a role of P2X7 receptors in processes that lead to neuronal death. The main objective of our study was to examine whether genetic deletion or pharmacological blockade of P2X7 receptors influenced dopaminergic cell death in various models of Parkinson's disease (PD). Results mRNA encoding P2X7 and P2X4 receptors was up-regulated after treatment of PC12 cells with 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP). P2X7 antagonists protected against MPTP and rotenone induced toxicity in the LDH assay, but failed to protect after rotenone treatment in the MTT assay in PC12 cells and in primary midbrain culture. In vivo MPTP and in vitro rotenone pretreatments increased the mRNA expression of P2X7 receptors in the striatum and substantia nigra of wild-type mice. Basal mRNA expression of P2X4 receptors was higher in P2X7 knockout mice and was further up-regulated by MPTP treatment. Genetic deletion or pharmacological inhibition of P2X7 receptors did not change survival rate or depletion of striatal endogenous dopamine (DA) content after in vivo MPTP or in vitro rotenone treatment. However, depletion of norepinephrine was significant after MPTP treatment only in P2X7 knockout mice. The basal ATP content was higher in the substantia nigra of wild-type mice, but the ADP level was lower. Rotenone treatment elicited a similar reduction in ATP content in the substantia nigra of both genotypes, whereas reduction of ATP was more pronounced after rotenone treatment in striatal slices of P2X7 deficient mice. Although the endogenous amino acid content remained unchanged, the level of the endocannabinoid, 2-AG, was elevated by rotenone in the striatum of wild-type mice, an effect that was absent in mice deficient in P2X7 receptors. Conclusions We conclude that P2X7 receptor deficiency or inhibition does not support the survival of dopaminergic neurons in an in vivo or in vitro models of PD. PMID:21542899

  10. The murine DUB-1 gene is specifically induced by the betac subunit of interleukin-3 receptor.

    PubMed Central

    Zhu, Y; Pless, M; Inhorn, R; Mathey-Prevot, B; D'Andrea, A D

    1996-01-01

    Cytokines regulate cell growth and differentiation by inducing the expression of specific target genes. We have recently isolated a cytokine-inducible, immediate-early cDNA, DUB-1, that encodes a deubiquitinating enzyme. The DUB-1 mRNA was specifically induced by the receptors for interleukin-3, granulocyte-macrophage colony-stimulating factor, and interleukin-5, suggesting a role for the beta common (betac subunit known to be shared by these receptors. In order to identify the mechanism of cytokine induction, we isolated a murine genomic clone for DUB-1 containing a functional promoter region. The DUB-1 gene contains two exons, and the nucleotide sequence of its coding region is identical to the sequence of DUB-1 cDNA. Various regions of the 5' flanking region of the DUB-1 gene were assayed for cytokine-inducible activity. An enhancer region that retains the beta c-specific inducible activity of the DUB-1 gene was identified. Enhancer activity was localized to a 112-bp fragment located 1.4 kb upstream from the ATG start codon. Gel mobility shift assays revealed two specific protein complexes that bound to this minimal enhancer region. One complex was induced by betac signaling, while the other was noninducible. Finally, the membrane-proximal region of human betac was required for DUB-1 induction. In conclusion, DUB-1 is the first example of an immediate-early gene that is induced by a specific subunit of a cytokine receptor. Further analysis of the DUB-1 enhancer element may reveal specific determinants of a betac-specific signaling pathway. PMID:8756639

  11. The role of kappa opioid receptors in stress-induced reinstatement of alcohol seeking in rats

    PubMed Central

    Funk, Douglas; Coen, Kathleen; Lê, A D

    2014-01-01

    Introduction Stress is related to heavy alcohol use and relapse in alcoholics. Using the reinstatement model, we have shown that corticotropin-releasing factor (CRF) underlies stress-induced relapse to alcohol seeking in laboratory rodents. Little is known about how other neurotransmitters interact with CRF in these effects. Dynorphin and its receptor (kappa opioid receptor, KOR) are involved in stress responses and in alcohol seeking. KOR and CRF receptors (CRF R) may interact in the production of stress-related behaviors but it is not known whether this interaction is involved in reinstatement of alcohol seeking. Methods Male Long Evans rats were trained to self-administer alcohol (12% w/v). After extinction of responding, we determined the effects of the KOR agonist, U50,488 (2.5, 5 mg/kg) on reinstatement of alcohol seeking, and their sensitivity to the selective KOR antagonist nor-binaltorphimine dihydrochloride (nor-BNI) (10 mg/kg) administered at different times before U50,488. We then examined the effects of nor-BNI on reinstatement induced by the stressor yohimbine (1.25 mg/kg) and on reinstatement induced by exposure to alcohol-associated cues. Finally, we determined whether CRF R1 blockade with antalarmin (10, 20 mg/kg) attenuates alcohol seeking induced by U50,488. Results U50,488 reinstated alcohol seeking. Prior treatment with nor-BNI 2, but not 24 h before administration of U50,488 or yohimbine blocked reinstatement induced by these drugs. Cue-induced reinstatement was blocked by nor-BNI administered 2 h prior to testing. Finally, U50,488-induced reinstatement was blocked by antalarmin. Conclusions These data further support a role for KOR in reinstatement of alcohol seeking under nonstress and stressful conditions and that KOR and CRF R interact in these effects. PMID:24944865

  12. Wood creosote prevents CRF-induced motility via 5-HT3 receptors in proximal and 5-HT4 receptors in distal colon in rats.

    PubMed

    Ataka, Koji; Kuge, Tomoo; Fujino, Kazunori; Takahashi, Toku; Fujimiya, Mineko

    2007-05-30

    Wood creosote has been used as an herbal medicine against acute diarrhea caused by food poisoning and has an inhibitory effect on colonic motility and enterotoxin-induced ion secretion. Since no previous studies have examined the effects of wood creosote on stress-induced alteration of colonic motility, we examined the effects on the colonic motility altered by intracerebroventricular (i.c.v.) injection of corticotropin-releasing factor (CRF), which is a key mediator in responses to stress. We recorded motor activity in proximal and distal colon of unrestrained conscious rats via two manometory catheters. The frequencies of phase III-like contraction and the % motor indices in both proximal and distal colon were measured. At the same time the number of fecal pellets excreted was counted. I.c.v. injection of CRF increased the motor activity in both proximal and distal colon, and these effects were completely antagonized by i.c.v. injection of a selective CRF type 1 antagonist but not by a CRF type 2 antagonist. Changes in colonic motility induced by CRF were reversed by intravenously administered wood creosote. Intraluminal administration of the 5-HT(3) receptor antagonist granisetron, or the 5-HT(4) receptor antagonist SB 204070 blocked the increase in colonic motility induced by i.c.v. injection of CRF. Wood creosote prevented the increase in colonic motility induced by the 5-HT(3) receptor agonist SR57227A in the proximal colon, while it prevented the increase in colonic motility induced by the 5-HT(4) receptor agonist RS67506 in the distal colon. These results indicate that wood creosote prevents the increase in colonic motility induced by CRF via 5-HT(3) receptors in the proximal colon, and via 5-HT(4) receptors in the distal colon, suggesting that wood creosote might be useful to treat stress-induced diarrhea.

  13. Neurokinin-1 receptor antagonists for chemotherapy-induced nausea and vomiting.

    PubMed

    Aziz, Fahad

    2012-07-01

    Chemotherapy can be a life-prolonging treatment for many cancer patients, but it is often associated with profound nausea and vomiting that is so distressing that patients may delay or decline treatment to avoid these side effects. The discovery of several NK1 receptor antagonists is a big revolution to dealt this problem. NK1 receptor antagonists prevent both acute and delayed chemotherapy-induced nausea and vomiting (CINV). These agents act centrally at NK-1 receptors in vomiting centers within the central nervous system to block their activation by substance P released as an unwanted consequence of chemotherapy. By controlling nausea and vomiting, these agents help improve patients' daily living and their ability to complete multiple cycles of chemotherapy. They are effective for both moderately and highly emetogenic chemotherapy regimens. Their use might be associated with increased infection rates; however, additional appraisal of specific data from RCTs is needed.

  14. Chronic treatment with clozapine, unlike haloperidol, does not induce changes in striatal D-2 receptor function in the rat.

    PubMed

    Rupniak, N M; Hall, M D; Mann, S; Fleminger, S; Kilpatrick, G; Jenner, P; Marsden, C D

    1985-08-01

    Comparison has been made of the effects on brain dopamine function of chronic administration of haloperidol or clozapine to rats for up to 12 months. In rats treated for 1-12 months with haloperidol (1.4-1.6 mg/kg/day), purposeless chewing jaw movements emerged. These movements were only observed after 12 months' treatment with clozapine (24-27 mg/kg/day). Apomorphine-induced (0.125-0.25 mg/kg) stereotyped behaviour was inhibited during 12 months treatment with haloperidol. Clozapine treatment was without effect. After 12 months, stereotypy induced by higher doses of apomorphine (0.5-1.0 mg/kg) was enhanced in haloperidol, but not clozapine, treated rats. Bmax for striatal 3H-spiperone binding was elevated throughout 12 months of haloperidol administration, but was not altered by clozapine treatment. Bmax for striatal 3H-NPA binding was only elevated after 12 months of haloperidol treatment; clozapine treatment was without effect. Bmax for 3H-piflutixol binding was not altered by haloperidol treatment, but was increased after 9 and 12 months of clozapine treatment. Dopamine (50 microM)-stimulated adenylate cyclase activity was inhibited after 1 month's haloperidol treatment but normal thereafter. Adenylate cyclase activity was not altered by chronic clozapine treatment. Striatal acetylcholine content was increased after 3 and 12 months of haloperidol or clozapine intake. These findings indicate that the chronic administration of the atypical neuroleptic clozapine does not produce changes in brain dopamine function which mirror those of the typical neuroleptic haloperidol. In particular, chronic administration of clozapine, unlike haloperidol, does not appear to induce striatal D-2 receptor supersensitivity. Unexpectedly, clozapine treatment, unlike haloperidol, altered D-1 receptor function.

  15. [Role of Transient Receptor Potential Channels in Paclitaxel- and Oxaliplatin-induced Peripheral Neuropathy].

    PubMed

    Taguchi, Kyoji

    2016-01-01

    Peripheral neuropathy is a common adverse effect of paclitaxel and oxaliplatin treatment. The major dose-limiting side effect of these drugs is peripheral sensory neuropathy. The symptoms of paclitaxel-induced neuropathy are mostly sensory and peripheral in nature, consisting of mechanical allodynia/hyperalgesia, tingling, and numbness. Oxaliplatin-induced neurotoxicity manifests as rapid-onset neuropathic symptoms that are exacerbated by cold exposure and as chronic neuropathy that develops after several treatment cycles. Although many basic and clinical researchers have studied anticancer drug-induced peripheral neuropathy, the mechanism is not well understood. In this review, we focus on (1) analysis of transient receptor potential vanilloid 1 (TRPV1) channel expression in the rat dorsal root ganglion (DRG) after paclitaxel treatment and (2) analysis of transient receptor potential ankyrin 1 (TRPA1) channel in the DRG after oxaliplatin treatment. This review describes that (1) paclitaxel-induced neuropathic pain may be the result of up-regulation of TRPV1 in small- and medium-diameter DRG neurons. In addition, paclitaxel treatment increases the release of substance P, but not calcitonin gene-related peptide, in the superficial layers of the spinal dorsal horn. (2) TRPA1 expression via activation of p38 mitogen-activated protein kinase in small-diameter DRG neurons, at least in part, contributes to the development of oxaliplatin-induced acute cold hyperalgesia. We suggest that TRPV1 or TRPA1 antagonists may be potential therapeutic lead compounds for treating anticancer drug-induced peripheral neuropathy.

  16. A role for muscarinic receptors in neutrophil extracellular trap formation and levamisole-induced autoimmunity

    PubMed Central

    Carmona-Rivera, Carmelo; Purmalek, Monica M.; Moore, Erica; Waldman, Meryl; Walter, Peter J.; Garraffo, H. Martin; Phillips, Karran A.; Preston, Kenzie L.; Graf, Jonathan; Grayson, Peter C.

    2017-01-01

    Levamisole, an anthelmintic drug with cholinergic properties, has been implicated in cases of drug-induced vasculitis when added to cocaine for profit purposes. Neutrophil extracellular trap (NET) formation is a cell death mechanism characterized by extrusion of chromatin decorated with granule proteins. Aberrant NET formation and degradation have been implicated in idiopathic autoimmune diseases that share features with levamisole-induced autoimmunity as well as in drug-induced autoimmunity. This study’s objective was to determine how levamisole modulates neutrophil biology and its putative effects on the vasculature. Murine and human neutrophils exposed to levamisole demonstrated enhanced NET formation through engagement of muscarinic subtype 3 receptor. Levamisole-induced NETosis required activation of Akt and the RAF/MEK/ERK pathway, ROS induction through the nicotinamide adenine dinucleotide phosphate oxidase, and peptidylarginine deiminase activation. Sera from two cohorts of patients actively using levamisole-adulterated cocaine displayed autoantibodies against NET components. Cutaneous biopsy material obtained from individuals exposed to levamisole suggests that neutrophils produce NETs in areas of vasculitic inflammation and thrombosis. NETs generated by levamisole were toxic to endothelial cells and impaired endothelium-dependent vasorelaxation. Stimulation of muscarinic receptors on neutrophils by cholinergic agonists may contribute to the pathophysiology observed in drug-induced autoimmunity through the induction of inflammatory responses and neutrophil-induced vascular damage. PMID:28194438

  17. Glucocorticoid-induced hypertension and cardiac injury: effects of mineralocorticoid and glucocorticoid receptor antagonism.

    PubMed

    Hattori, Takuya; Murase, Tamayo; Iwase, Erika; Takahashi, Keiji; Ohtake, Masafumi; Tsuboi, Koji; Ohtake, Mayuko; Miyachi, Masaaki; Murohara, Toyoaki; Nagata, Kohzo

    2013-02-01

    Glucocorticoids are widely administered for the treatment of various disorders, although their long-term use results in adverse effects associated with glucocorticoid excess. We investigated the pathophysiological roles of glucocorticoid receptors (GRs) and mineralocorticoid receptors (MRs) in the cardiac changes induced by exogenous corticosterone in rats. Corticosterone or vehicle was injected twice daily in rats from 8 to 12 weeks of age. The effects of the GR antagonist RU486, the MR antagonist spironolactone, or both agents on corticosterone action were also determined. Corticosterone induced hypertension, left ventricular (LV) fibrosis, and LV diastolic dysfunction. Neither RU486 nor spironolactone affected corticosterone-induced hypertension, whereas spironolactone, but not RU486, attenuated the effects of corticosterone on LV fibrosis and diastolic function. Corticosterone also increased cardiac oxidative stress and inflammation in a manner sensitive to spironolactone but not to RU486. The corticosterone-induced LV atrophy was not affected by either RU486 or spironolactone. Our results implicate MRs in the cardiac fibrosis and diastolic dysfunction, but not MRs or GRs in the cardiac atrophy, induced by corticosterone. Neither MRs nor GRs appear to contribute to corticosterone-induced hypertension.

  18. Ovariectomy-induced changes in aged beagles: Histomorphometry and mineral content of the rib

    SciTech Connect

    Wilson, A.K.; Bhattacharyya, M.H.; Hurst, D.; Miller, S.; Sacco-Gibson, N.

    1997-08-01

    The effects of ovariectomy on the aged beagle skeleton were studied by histomorphometric analysis of the cortical bone in sequential rib biopsies. Biopsies were taken from each ovariectomized (OV) or sham-operated (SO) dog at the time of surgery and at 1, 4, and 8.5 months after surgery. Tetracycline, calcein, and xylenol orange, respectively, were administered by a fluorochrome labeling procedure (2d-10d-2d) just prior to each postoperative biopsy to provide markers of bone formation. Analysis of sequential biopsies provided a means to follow the response to ovariectomy over time and compare each animal against its own baseline. Examination of sequential biopsies indicated that cortical porosity increased by the fourth month after ovariectomy and remained high at 8.5 months. Ovariectomy did not influence histomorphometric indices at one month after surgery, but substantial differences were observed at later times. Ovariectomy stimulated a transient increase in bone formation and was increased six-fold over that of SO dogs at four months. Ribs were also analyzed for mineral content at necropsy. The rib was heterogeneous along its length for calcium content and concentration. In the midrib where biopsies for histomorphometric analysis were taken, ovariectomy induced a decrease in mass and mineral content; total calcium was decreased by approximately 31%. These data demonstrate that the rib cortical bone is a responsive site for the effects of ovariectomy in female dogs.

  19. Characterization of Induced Pluripotent Stem Cell Microvesicle Genesis, Morphology and Pluripotent Content

    PubMed Central

    Zhou, Jing; Ghoroghi, Shima; Benito-Martin, Alberto; Wu, Hao; Unachukwu, Uchenna John; Einbond, Linda Saxe; Guariglia, Sara; Peinado, Hector; Redenti, Stephen

    2016-01-01

    Microvesicles (MVs) are lipid bilayer-covered cell fragments that range in diameter from 30 nm–1uM and are released from all cell types. An increasing number of studies reveal that MVs contain microRNA, mRNA and protein that can be detected in the extracellular space. In this study, we characterized induced pluripotent stem cell (iPSC) MV genesis, content and fusion to retinal progenitor cells (RPCs) in vitro. Nanoparticle tracking revealed that iPSCs released approximately 2200 MVs cell/hour in the first 12 hrs with an average diameter of 122 nm. Electron and light microscopic analysis of iPSCs showed MV release via lipid bilayer budding. The mRNA content of iPSC MVs was characterized and revealed the presence of the transcription factors Oct-3/4, Nanog, Klf4, and C-Myc. The protein content of iPSCs MVs, detected by immunogold electron microscopy, revealed the presence of the Oct-3/4 and Nanog. Isolated iPSC MVs were shown to fuse with RPCs in vitro at multiple points along the plasma membrane. These findings demonstrate that the mRNA and protein cargo in iPSC MVs have established roles in maintenance of pluripotency. Building on this work, iPSC derived MVs may be shown to be involved in maintaining cellular pluripotency and may have application in regenerative strategies for neural tissue. PMID:26797168

  20. An Opioid Agonist that Does Not Induce μ-Opioid Receptor—Arrestin Interactions or Receptor Internalization

    PubMed Central

    Groer, C. E.; Tidgewell, K.; Moyer, R. A.; Harding, W. W.; Rothman, R. B.; Prisinzano, T. E.; Bohn, L. M.

    2013-01-01

    G protein-coupled receptor desensitization and trafficking are important regulators of opioid receptor signaling that can dictate overall drug responsiveness in vivo. Furthermore, different μ-opioid receptor (μOR) ligands can lead to varying degrees of receptor regulation, presumably because of distinct structural conformations conferred by agonist binding. For example, morphine binding produces a μOR with low affinity for β-arrestin proteins and limited receptor internalization, whereas enkephalin analogs promote robust trafficking of both β-arrestins and the receptors. Here, we evaluate μOR trafficking in response to activation by a novel μ-selective agonist derived from the naturally occurring plant product, salvinorin A. It is interesting that this compound, termed herkinorin, does not promote the recruitment of β-arrestin-2 to the μOR and does not lead to receptor internalization. Moreover, whereas G protein-coupled receptor kinase overexpression can promote morphine-induced β-arrestin interactions and μOR internalization, such manipulations do not promote herkinorin-induced trafficking. Studies in mice have shown that β-arrestin-2 plays an important role in the development of morphine-induced tolerance, constipation, and respiratory depression. Therefore, drugs that can activate the receptor without recruiting the arrestins may be a promising step in the development of opiate analgesics that distinguish between agonist activity and receptor regulation and may ultimately lead to therapeutics designed to provide pain relief without the adverse side effects normally associated with the opiate narcotics. PMID:17090705

  1. The modulatory role of M2 muscarinic receptor on apomorphine-induced yawning and genital grooming.

    PubMed

    Gamberini, Maria Thereza; Bolognesi, Maria Laura; Nasello, Antonia Gladys

    2012-12-07

    The interaction between dopaminergic and cholinergic pathways in the induction of behavioral responses has been previously established. In the brain, M2 receptors are found predominantly in presynaptic cholinergic neurons as autoreceptors, and in dopaminergic neurons as heteroceptors, suggesting a control role of acetylcholine and dopamine release, respectively. Our aim was to investigate the role of M2 receptors on the yawning and genital grooming of rats induced by apomorphine, a dopaminergic receptor agonist, focusing on the interaction between cholinergic and dopaminergic pathways. Initially, the effect of atropine, a non-selective muscarinic antagonist, on yawning and genital grooming induced by apomorphine (100 μg/kg s.c.) was analyzed. Atropine doses of 0.5, 1 and 2 mg/kg i.p. were administered to Wistar rats 30 min before induction of the behavioral responses by apomorphine. Number of yawns and time spent genital grooming were quantified over a 60 min period. Apomorphine-induced yawning was increased by low dose (0.5 mg/kg i.p.) but not by high doses (1 and 2 mg/kg, i.p.) of atropine. Genital grooming was antagonized by 2 mg/kg i.p. of atropine and showed no changes at the other doses tested. Tripitramine, a selective M2 cholinergic antagonist, was used as a tool for distinguishing between M2 and all other muscarinic receptor subtypes in yawning and genital grooming. Tripitramine doses of 0.01, 0.02 and 0.04 μmol/kg i.p. were administered to Wistar rats 30 min before apomorphine (100 μg/kg s.c.). Number of yawns and time spent genital grooming were also quantified over a 60 min period. Tripitramine 0.01 μmol/kg increased all parameters. Higher doses, which possibly block all subtypes of muscarinic receptor, did not modify the response of apomorphine, suggesting a non-selective effect of tripitramine at these doses. Given that low doses of tripitramine increased the behavioral responses induced by apomorphine and that the main distribution of the M2

  2. B1-kinin receptors modulate Mesobuthus tamulus venom-induced vasosensory reflex responses in anesthetized rats

    PubMed Central

    Singh, Sanjeev K.; Deshpande, Shripad B.

    2016-01-01

    Objective: Intra-arterial injection of Mesobuthus tamulus (BT) venom produces reflex vasosensory responses modulating cardiorespiratory parameters in albino rats. The present study was conducted to understand the role of kinin receptors in modulating vasosensory reflexes evoked by BT venom. Materials and Methods: In urethane-anesthetized rats, tracheostomy was performed to keep the airway patent. The femoral artery was cannulated proximally, as well as distally, to record the blood pressure (BP) and to inject the chemicals, respectively. Electrocardiographic and respiratory excursions were recorded to compute the heart rate (HR) and respiratory rate (RR). A group of animals was pretreated with saline/kinin receptor antagonists intra-arterially (B1/B2 receptor antagonists) before the injection of venom. Results: After intra-arterial injection of BT venom (1 mg/kg), there was an immediate increase in RR, which reached to 40% within 30 s, followed by a decrease of 40%. Further, there was sustained increase in RR (50%) up to 60 min. The BP started to increase at 40 s, peaking at 5 min (50%), and remained above the initial level up to 60 min. The bradycardiac response started after 5 min which peaked (50% of initial) at 25 min and remained at that level up to 60 min. In B1 receptor antagonist (des-Arg) pretreated animals, venom-induced cardiovascular responses were attenuated (by 20–25% in mean arterial pressure and HR) significantly but not in B2 receptor antagonist (Hoe-140) pretreated animals. Either of the antagonists failed to alter the RR responses. Conclusions: BT venom-induced vasosensory reflex responses modulating cardiovascular parameters are mediated via B1-kinin receptors in anesthetized rats. PMID:27756949

  3. Subchronic treatment with antiepileptic drugs modifies pentylenetetrazol-induced seizures in mice: Its correlation with benzodiazepine receptor binding

    PubMed Central

    Rocha, Luisa

    2008-01-01

    Experiments using male CD1 mice were carried out to investigate the effects of subchronic (daily administration for 8 days) pretreatments with drugs enhancing GABAergic transmission (diazepam, 10 mg/kg, ip; gabapentin, 100 mg/kg, po; or vigabatrin, 500 mg/kg, po) on pentylenetetrazol (PTZ)-induced seizures, 24 h after the last injection. Subchronic administration of diazepam reduced latencies to clonus, tonic extension and death induced by PTZ. Subchronic vigabatrin produced enhanced latency to the first clonus but faster occurrence of tonic extension and death induced by PTZ. Subchronic gabapentin did not modify PTZ-induced seizures. Autoradiography experiments revealed reduced benzodiazepine receptor binding in several brain areas after subchronic treatment with diazepam or gabapentin, whereas subchronic vigabatrin did not induce significant receptor changes. The present results indicate differential effects induced by the subchronic administration of diazepam, vigabatrin, and gabapentin on the susceptibility to PTZ-induced seizures, benzodiazepine receptor binding, or both. PMID:18830436

  4. Postnatal dexamethasone-induced programmed hypertension is related to the regulation of melatonin and its receptors.

    PubMed

    Chang, Hsin-Yu; Tain, You-Lin

    2016-04-01

    Adulthood hypertension can be programmed by glucocorticoid exposure in early life. We found that maternal melatonin therapy prevents postnatal dexamethasone (DEX)-induced programmed hypertension. Melatonin acts through specific receptors, including MT1 and MT2 membrane receptors, and retinoid related orphan nuclear receptors of the RZR/ROR family. Thus we tested whether postnatal DEX-induced hypertension is related to changes of melatonin receptors in the kidney and heart, which was preserved by maternal melatonin therapy. Male neonates were assigned to four groups (n=6-8/group): control, DEX, control+melatonin (MEL), and DEX+MEL. Male rat pups were injected i.p. with DEX on d 1 (0.5 mg/kg BW), d 2 (0.3 mg/kg BW), and d 3 (0.1 mg/kg BW) after birth. Melatonin was administered in drinking water (0.01%) during the lactation period. We found DEX group developed hypertension at 16 weeks of age, which melatonin therapy prevented. Postnatal DEX treatment increased mRNA expression of MT1 and MT2, while decreased RORα and RZRβ in the kidney. These changes were prevented by melatonin therapy. Postnatal DEX decreased protein level of MT2 in the kidney, which was attenuated by melatonin therapy. Renal protein level of RORα was higher in DEX+MEL group compared to control and DEX group. Renal melatonin level was higher in the MEL and DEX+MEL groups compared to control. We concluded that melatonin therapy has long-term protection on postnatal DEX-induced programmed hypertension, which is associated with regulation on melatonin receptors in the kidney. Our findings would offer potential therapeutic approaches to prevent programmed hypertension in premature baby receiving glucocorticoids.

  5. Involvement of cannabinoid receptors in infrasonic noise-induced neuronal impairment.

    PubMed

    Ma, Lei; He, Hua; Liu, Xuedong; Zhang, Guangyun; Li, Li; Yan, Song; Li, Kangchu; Shi, Ming

    2015-08-01

    Excessive exposure to infrasound, a kind of low-frequency but high-intensity sound noise generated by heavy transportations and machineries, can cause vibroacoustic disease which is a progressive and systemic disease, and finally results in the dysfunction of central nervous system. Our previous studies have demonstrated that glial cell-mediated inflammation may contribute to infrasound-induced neuronal impairment, but the underlying mechanisms are not fully understood. Here, we show that cannabinoid (CB) receptors may be involved in infrasound-induced neuronal injury. After exposure to infrasound at 16 Hz and 130 dB for 1-14 days, the expression of CB receptors in rat hippocampi was gradually but significantly decreased. Their expression levels reached the minimum after 7- to 14-day exposure during which the maximum number of apoptotic cells was observed in the CA1. 2-Arachidonoylglycerol (2-AG), an endogenous agonist for CB receptors, reduced the number of infrasound-triggered apoptotic cells, which, however, could be further increased by CB receptor antagonist AM251. In animal behavior performance test, 2-AG ameliorated the infrasound-impaired learning and memory abilities of rats, whereas AM251 aggravated the infrasound-impaired learning and memory abilities of rats. Furthermore, the levels of proinflammatory cytokines tumor necrosis factor alpha and interleukin-1β in the CA1 were upregulated after infrasound exposure, which were attenuated by 2-AG but further increased by AM251. Thus, our results provide the first evidence that CB receptors may be involved in infrasound-induced neuronal impairment possibly by affecting the release of proinflammatory cytokines.

  6. Endothelial Mineralocorticoid Receptor Deletion Prevents Diet-Induced Cardiac Diastolic Dysfunction in Females.

    PubMed

    Jia, Guanghong; Habibi, Javad; DeMarco, Vincent G; Martinez-Lemus, Luis A; Ma, Lixin; Whaley-Connell, Adam T; Aroor, Annayya R; Domeier, Timothy L; Zhu, Yi; Meininger, Gerald A; Barrett Mueller, Katelee; Jaffe, Iris Z; Sowers, James R

    2015-12-01

    Overnutrition and insulin resistance are especially prominent risk factors for the development of cardiac diastolic dysfunction in females. We recently reported that consumption of a Western diet (WD) containing excess fat (46%), sucrose (17.5%), and high fructose corn syrup (17.5%) for 16 weeks resulted in cardiac diastolic dysfunction and aortic stiffening in young female mice and that these abnormalities were prevented by mineralocorticoid receptor blockade. Herein, we extend those studies by testing whether WD-induced diastolic dysfunction and factors contributing to diastolic impairment, such as cardiac fibrosis, hypertrophy, inflammation, and impaired insulin signaling, are modulated by excess endothelial cell mineralocorticoid receptor signaling. Four-week-old female endothelial cell mineralocorticoid receptor knockout and wild-type mice were fed mouse chow or WD for 4 months. WD feeding resulted in prolonged relaxation time, impaired diastolic septal wall motion, and increased left ventricular filling pressure indicative of diastolic dysfunction. This occurred in concert with myocardial interstitial fibrosis and cardiomyocyte hypertrophy that were associated with enhanced profibrotic (transforming growth factor β1/Smad) and progrowth (S6 kinase-1) signaling, as well as myocardial oxidative stress and a proinflammatory immune response. WD also induced cardiomyocyte stiffening, assessed ex vivo using atomic force microscopy. Conversely, endothelial cell mineralocorticoid receptor deficiency prevented WD-induced diastolic dysfunction, profibrotic, and progrowth signaling, in conjunction with reductions in macrophage proinflammatory polarization and improvements in insulin metabolic signaling. Therefore, our findings indicate that increased endothelial cell mineralocorticoid receptor signaling associated with consumption of a WD plays a key role in the activation of cardiac profibrotic, inflammatory, and growth pathways that lead to diastolic dysfunction in

  7. Glycogen content regulates peroxisome proliferator activated receptor-∂ (PPAR-∂) activity in rat skeletal muscle.

    PubMed

    Philp, Andrew; MacKenzie, Matthew G; Belew, Micah Y; Towler, Mhairi C; Corstorphine, Alan; Papalamprou, Angela; Hardie, D Grahame; Baar, Keith

    2013-01-01

    Performing exercise in a glycogen depleted state increases skeletal muscle lipid utilization and the transcription of genes regulating mitochondrial β-oxidation. Potential candidates for glycogen-mediated metabolic adaptation are the peroxisome proliferator activated receptor (PPAR) coactivator-1α (PGC-1α) and the transcription factor/nuclear receptor PPAR-∂. It was therefore the aim of the present study to examine whether acute exercise with or without glycogen manipulation affects PGC-1α and PPAR-∂ function in rodent skeletal muscle. Twenty female Wistar rats were randomly assigned to 5 experimental groups (n = 4): control [CON]; normal glycogen control [NG-C]; normal glycogen exercise [NG-E]; low glycogen control [LG-C]; and low glycogen exercise [LG-E]). Gastrocnemius (GTN) muscles were collected immediately following exercise and analyzed for glycogen content, PPAR-∂ activity via chromatin immunoprecipitation (ChIP) assays, AMPK α1/α2 kinase activity, and the localization of AMPK and PGC-1α. Exercise reduced muscle glycogen by 47 and 75% relative to CON in the NG-E and LG-E groups, respectively. Exercise that started with low glycogen (LG-E) finished with higher AMPK-α2 activity (147%, p<0.05), nuclear AMPK-α2 and PGC-1α, but no difference in AMPK-α1 activity compared to CON. In addition, PPAR-∂ binding to the CPT1 promoter was significantly increased only in the LG-E group. Finally, cell reporter studies in contracting C2C12 myotubes indicated that PPAR-∂ activity following contraction is sensitive to glucose availability, providing mechanistic insight into the association between PPAR-∂ and glycogen content/substrate availability. The present study is the first to examine PPAR-∂ activity in skeletal muscle in response to an acute bout of endurance exercise. Our data would suggest that a factor associated with muscle contraction and/or glycogen depletion activates PPAR-∂ and initiates AMPK translocation in skeletal muscle in

  8. Regulation of epidermal growth factor receptor signalling by inducible feedback inhibitors.

    PubMed

    Segatto, Oreste; Anastasi, Sergio; Alemà, Stefano

    2011-06-01

    Signalling by the epidermal growth factor receptor (EGFR) controls morphogenesis and/or homeostasis of several tissues from worms to mammals. The correct execution of these programmes requires the generation of EGFR signals of appropriate strength and duration. This is obtained through a complex circuitry of positive and negative feedback regulation. Feedback inhibitory mechanisms restrain EGFR activity in time and space, which is key to ensuring that receptor outputs are commensurate to the cell and tissue needs. Here, we focus on the emerging field of inducible negative feedback regulation of the EGFR in mammals. In mammalian cells, four EGFR inducible feedback inhibitors (IFIs), namely LRIG1, RALT (also known as MIG6 and ERRFI1), SOCS4 and SOCS5, have been discovered recently. EGFR IFIs are expressed de novo in the context of early or delayed transcriptional responses triggered by EGFR activation. They all bind to the EGFR and suppress receptor signalling through several mechanisms, including catalytic inhibition and receptor downregulation. Here, we review the mechanistic basis of IFI signalling and rationalise the function of IFIs in light of gene-knockout studies that assign LRIG1 and RALT an essential role in restricting cell proliferation. Finally, we discuss how IFIs might participate in system control of EGFR signalling and highlight the emerging roles for IFIs in the suppression of EGFR-driven tumorigenesis.

  9. Antigen receptor-induced B lymphocyte apoptosis mediated via a protease of the caspase family.

    PubMed

    Andjelic, S; Liou, H C

    1998-02-01

    An extensive body of data, in a variety of systems, denoted the caspase family of proteases as a key player in the execution of programmed cell death. This family consists of cysteine proteases that cleave after asparagine-containing motifs. It is well established that the caspases are essential for the apoptosis mediated by Fas (CD95) and TNF receptor p55, molecules that contain the "death domain" in the cytoplasmic tail. However, little is known about the mechanisms underlying the antigen receptor-mediated cell death in B lymphocytes, a process instrumental in negative selection of potentially autoreactive B cells. Here, we investigated the involvement of caspases in cell death triggered via the antigen receptor in B lymphocytes (BCR) by using specific inhibitors. Initially, we used a well-established cell line, CH31, which is a model of B cell tolerance, to demonstrate that these proteases indeed participate in the BCR-induced apoptotic pathway. Next, we confirmed the physiological relevance of the caspase-mediated cell death pathway in splenic B cell populations isolated ex vivo that were induced to undergo apoptosis by extensive cross-linking of their BCR. Most interestingly, our data demonstrated that caspases regulate not only the nuclear DNA fragmentation, but also the surface membrane phosphatidylserine translocation as well as the degradation of a specific nuclear substrate. Taken together, this report supports the hypothesis that regulation of the caspase family is crucial in controlling the life/death decision in B lymphocytes mediated by the antigen receptor signal transduction.

  10. Profound and rapid reduction in body temperature induced by the melanocortin receptor agonists.

    PubMed

    Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

    2014-08-22

    The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5'AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII's effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature.

  11. NMDA Receptors on Dopaminoceptive Neurons Are Essential for Drug-Induced Conditioned Place Preference123

    PubMed Central

    Tokarski, Krzysztof; Bobula, Bartosz; Zygmunt, Magdalena; Smutek, Magdalena; Kamińska, Katarzyna; Gołembiowska, Krystyna; Hess, Grzegorz; Przewlocki, Ryszard

    2016-01-01

    Abstract Plasticity of the brain’s dopamine system plays a crucial role in adaptive behavior by regulating appetitive motivation and the control of reinforcement learning. In this study, we investigated drug- and natural-reward conditioned behaviors in a mouse model in which the NMDA receptor-dependent plasticity of dopaminoceptive neurons was disrupted. We generated a transgenic mouse line with inducible selective inactivation of the NR1 subunit in neurons expressing dopamine D1 receptors (the NR1D1CreERT2 mice). Whole-cell recordings of spontaneous EPSCs on neurons in the nucleus accumbens confirmed that a population of neurons lacked the NMDA receptor-dependent component of the current. This effect was accompanied by impaired long-term potentiation in the nucleus accumbens and in the CA1 area of the ventral, but not the dorsal, hippocampus. Mutant mice did not differ from control animals when tested for pavlovian or instrumental conditioning. However, NR1D1CreERT2 mice acquired no preference for a context associated with administration of drugs of abuse. In the conditioned place preference paradigm, mutant mice did not spend more time in the context paired with cocaine, morphine, or ethanol, although these mice acquired a preference for sucrose jelly and an aversion to naloxone injections, as normal. Thus, we observed that the selective inducible ablation of the NMDA receptors specifically blocks drug-associated context memory with no effect on positive reinforcement in general. PMID:27294197

  12. NMDA Receptors on Dopaminoceptive Neurons Are Essential for Drug-Induced Conditioned Place Preference.

    PubMed

    Sikora, Magdalena; Tokarski, Krzysztof; Bobula, Bartosz; Zajdel, Joanna; Jastrzębska, Kamila; Cieślak, Przemysław Eligiusz; Zygmunt, Magdalena; Sowa, Joanna; Smutek, Magdalena; Kamińska, Katarzyna; Gołembiowska, Krystyna; Engblom, David; Hess, Grzegorz; Przewlocki, Ryszard; Rodriguez Parkitna, Jan

    2016-01-01

    Plasticity of the brain's dopamine system plays a crucial role in adaptive behavior by regulating appetitive motivation and the control of reinforcement learning. In this study, we investigated drug- and natural-reward conditioned behaviors in a mouse model in which the NMDA receptor-dependent plasticity of dopaminoceptive neurons was disrupted. We generated a transgenic mouse line with inducible selective inactivation of the NR1 subunit in neurons expressing dopamine D1 receptors (the NR1(D1CreERT2) mice). Whole-cell recordings of spontaneous EPSCs on neurons in the nucleus accumbens confirmed that a population of neurons lacked the NMDA receptor-dependent component of the current. This effect was accompanied by impaired long-term potentiation in the nucleus accumbens and in the CA1 area of the ventral, but not the dorsal, hippocampus. Mutant mice did not differ from control animals when tested for pavlovian or instrumental conditioning. However, NR1(D1CreERT2) mice acquired no preference for a context associated with administration of drugs of abuse. In the conditioned place preference paradigm, mutant mice did not spend more time in the context paired with cocaine, morphine, or ethanol, although these mice acquired a preference for sucrose jelly and an aversion to naloxone injections, as normal. Thus, we observed that the selective inducible ablation of the NMDA receptors specifically blocks drug-associated context memory with no effect on positive reinforcement in general.

  13. Toxaphene-induced mouse liver tumorigenesis is mediated by the constitutive androstane receptor.

    PubMed

    Wang, Zemin; Li, Xilin; Wu, Qiangen; Lamb, James C; Klaunig, James E

    2017-02-20

    Toxaphene was shown to increase liver tumor incidence in B6C3F1 mice following chronic dietary exposure. Preliminary evidence supported a role for the constitutive androstane receptor (CAR) in the mode of action of toxaphene-induced mouse liver tumors. However, these results could not rule out a role for the pregnane X receptor (PXR) in liver tumor formation. To define further the nuclear receptors involved in this study, we utilized CAR, PXR and PXR/CAR knockout mice (CAR(-/-) , PXR(-/-) and PXR(-/-) /CAR(-/-) ) along with the wild-type C57BL/6. In this study CAR-responsive genes Cyp3a11 and Cyp2b10 were induced in the liver of C57BL/6 (wild-type) mice by toxaphene (30-570-fold) (at the carcinogenic dose 320 ppm) and phenobarbital (positive control) (16-420-fold) following 14 days' dietary treatment. In contrast, in CAR(-/-) mice, no induction of these genes was seen following treatment with either chemical. Cyp3a11 and Cyp2b10 were also induced in PXR(-/-) mice with toxaphene and phenobarbital but were not changed in treated PXR(-/-) /CAR(-/-) mice. Similarly, induction of liver pentoxyresorufin-O-deethylase (CAR activation) activity by toxaphene and phenobarbital was absent in CAR(-/-) and PXR(-/-) /CAR(-/-) mice treated with phenobarbital or toxaphene. Ethoxyresorufin-O-deethylase (EROD, represents aryl hydrocarbon receptor activation) activity in CAR(-/-) mice treated with toxaphene or phenobarbital was increased compared with untreated control, but lower overall in activity in comparison to the wild-type mouse. Liver EROD activity was also induced by both phenobarbital and toxaphene in the PXR(-/-) mice but not in the PXR(-/-) /CAR(-/-) mice. Toxaphene treatment increased 7-benzyloxyquinoline activity (a marker for PXR activation) in a similar pattern to that seen with pentoxyresorufin-O-deethylase. These observations indicate that EROD and PXR activation are evidence, as expected, of secondary overlap to primary CAR receptor activation. Together, these

  14. An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content1[OPEN

    PubMed Central

    Wu, Lin; Ma, Nan; Zhang, Yi; Feng, Ming

    2017-01-01

    In many plant species, including rose (Rosa hybrida), flower senescence is promoted by the gaseous hormone ethylene and inhibited by the cytokinin (CTK) class of hormones. However, the molecular mechanisms underlying these antagonistic effects are not well understood. In this study, we characterized the association between a pathogenesis-related PR-10 family gene from rose (RhPR10.1) and the hormonal regulation of flower senescence. Quantitative reverse transcription PCR analysis showed that RhPR10.1 was expressed at high levels during senescence in different floral organs, including petal, sepal, receptacle, stamen, and pistil, and that expression was induced by ethylene treatment. Silencing of RhPR10.1 expression in rose plants by virus-induced gene silencing accelerated flower senescence, which was accompanied by a higher ion leakage rate in the petals, as well as increased expression of the senescence marker gene RhSAG12. CTK content and the expression of three CTK signaling pathway genes were reduced in RhPR10.1-silenced plants, and the accelerated rate of petal senescence that was apparent in the RhPR10.1-silenced plants was restored to normal levels by CTK treatment. Finally, RhHB6, a homeodomain-Leu zipper I transcription factor, was observed to bind to the RhPR10.1 promoter, and silencing of its expression also promoted flower senescence. Our results reveal an ethylene-induced RhHB6-RhPR10.1 regulatory module that functions as a brake of ethylene-promoted senescence through increasing the CTK content. PMID:27879388

  15. Laser-induced transepidermal elimination of dermal content by fractional photothermolysis

    NASA Astrophysics Data System (ADS)

    Hantash, Basil M.; Bedi, Vikramaditya P.; Sudireddy, Vasanthi; Struck, Steven K.; Herron, G. Scott; Chan, Kin Foong

    2006-07-01

    The wound healing process in skin is studied in human subjects treated with fractional photothermolysis. In-vivo histological evaluation of vacuoles formed over microthermal zones (MTZs) and their content is undertaken. A 30-W, 1550-nm single-mode fiber laser system delivers an array of 60 µm or 140 µm 1/e2 incidence microbeam spot size at variable pulse energy and density. Treatments span from 6 to 20 mJ with skin excisions performed 1-day post-treatment. Staining with hematoxylin and eosin demonstrates an intact stratum corneum with vacuolar formation within the epidermis. The re-epithelialization process with repopulation of melanocytes and keratinocytes at the basal layer is apparent by 1-day post-treatment. The dermal-epidermal (DE) junction is weakened and separated just above zones of dermal coagulation. Complete loss of dermal cell viability is noted within the confines of the MTZs 1-day post-treatment, as assessed by lactate dehydrogenase. All cells falling outside the irradiation field remain viable. Content within the epidermal vacuoles stain positively with Gomori trichrome, suggesting a dermal origin. However, the positive staining could be due to loss of specificity after thermal alteration. Nevertheless, this dermal extrusion hypothesis is supported by very specific positive staining with an antihuman elastin antibody. Fractional photothermolysis creates microthermal lesions that allow transport and extrusion of dermal content through a compromised DE junction. Some dermal material is incorporated into the microepidermal necrotic debris and shuttled up the epidermis to eventually be exfoliated through the stratum corneum. This is the first report of a nonablative laser-induced transport mechanism by which dermal content can be predictably extruded biologically through the epidermis. Thus, treatment with the 1550-nm fiber laser may provide the first therapeutic option for clinical indications, including pigmentary disorders such as medically

  16. Cranberries inhibit LDL oxidation and induce LDL receptor expression in hepatocytes.

    PubMed

    Chu, Yi-Fang; Liu, Rui Hai

    2005-08-26

    Cardiovascular disease (CVD) is the leading cause of death in most industrialized countries. Cranberries were evaluated for their potential roles in dietary prevention of CVD. Cranberry extracts were found to have potent antioxidant capacity preventing in vitro LDL oxidation with increasing delay and suppression of LDL oxidation in a dose-dependent manner. The antioxidant activity of 100 g cranberries against LDL oxidation was equivalent to 1000 mg vitamin C or 3700 mg vitamin E. Cranberry extracts also significantly induced expression of hepatic LDL receptors and increased intracellular uptake of cholesterol in HepG2 cells in vitro in a dose-dependent manner. This suggests that cranberries could enhance clearance of excessive plasma cholesterol in circulation. We propose that additive or synergistic effects of phytochemicals in cranberries are responsible for the inhibition of LDL oxidation, the induced expression of LDL receptors, and the increased uptake of cholesterol in hepatocytes.

  17. T-cell receptor-induced JNK activation requires proteolytic inactivation of CYLD by MALT1.

    PubMed

    Staal, Jens; Driege, Yasmine; Bekaert, Tine; Demeyer, Annelies; Muyllaert, David; Van Damme, Petra; Gevaert, Kris; Beyaert, Rudi

    2011-05-04

    The paracaspase mucosa-associated lymphoid tissue 1 (MALT1) is central to lymphocyte activation and lymphomagenesis. MALT1 mediates antigen receptor signalling to NF-κB by acting as a scaffold protein. Furthermore, MALT1 has proteolytic activity that contributes to optimal NF-κB activation by cleaving the NF-κB inhibitor A20. Whether MALT1 protease activity is involved in other signalling pathways, and the identity of the relevant substrates, is unknown. Here, we show that T-cell receptors (TCR) activation, as well as overexpression of the oncogenic API2-MALT1 fusion protein, results in proteolytic inactivation of CYLD by MALT1, which is specifically required for c-jun N-terminal kinase (JNK) activation and the inducible expression of a subset of genes. These results indicate a novel role for MALT1 proteolytic activity in TCR-induced JNK activation and reveal CYLD cleavage as the underlying mechanism.

  18. Overexpression of Annexin II Receptor-Induced Autophagy Protects Against Apoptosis in Uveal Melanoma Cells.

    PubMed

    Zhang, Yuelu; Song, Hongyuan; Guo, Ting; Zhu, Yongzhe; Tang, Hailin; Qi, Zhongtian; Zhao, Ping; Zhao, Shihong

    2016-05-01

    Uveal melanoma is the most common primary malignant intraocular tumor in adults and still lacks effective systemic therapies. Annexin A2 receptor (AXIIR), a receptor for Annexin II, was demonstrated to play an important role in multiple cells, but its role in uveal melanoma cells remains exclusive. Herein, the authors reported that overexpression of AXIIR was able to reduce cell viability and activate apoptosis apparently in the Mum2C uveal melanoma cell line. Meanwhile, overexpression of AXIIR could induce autophagy and increase autophagy flux. After autophagy was inhibited by chloroquine, enhanced apoptosis and cytotoxicity could be detected. In summary, these data highlighted the crucial role of AXIIR in reducing Mum2C cell viability through inducing apoptosis, while autophagy played a protective role in this process. Interference of this gene may be a promising method for uveal melanoma therapy and combination with specific inhibitor of autophagy may serve as a supplementary.

  19. Aldosterone-induced brain MAPK signaling and sympathetic excitation are angiotensin II type-1 receptor dependent.

    PubMed

    Zhang, Zhi-Hua; Yu, Yang; Wei, Shun-Guang; Felder, Robert B

    2012-02-01

    Angiotensin II (ANG II)-induced mitogen-activated protein kinase (MAPK) signaling upregulates angiotensin II type-1 receptors (AT(1)R) in hypothalamic paraventricular nucleus (PVN) and contributes to AT(1)R-mediated sympathetic excitation in heart failure. Aldosterone has similar effects to increase AT(1)R expression in the PVN and sympathetic drive. The present study was undertaken to determine whether aldosterone also activates the sympathetic nervous system via MAPK signaling and, if so, whether its effect is independent of ANG II and AT(1)R. In anesthetized rats, a 4-h intravenous infusion of aldosterone induced increases (P < 0.05) in phosphorylated (p-) p44/42 MAPK in PVN, PVN neuronal excitation, renal sympathetic nerve activity (RSNA), mean blood pressure (MBP), and heart rate (HR). Intracerebroventricular or bilateral PVN microinjection of the p44/42 MAPK inhibitor PD-98059 reduced the aldosterone-induced RSNA, HR, and MBP responses. Intracerebroventricular pretreatment (5 days earlier) with pooled small interfering RNAs targeting p44/42 MAPK reduced total and p-p44/42 MAPK, aldosterone-induced c-Fos expression in the PVN, and the aldosterone-induced increases in RSNA, HR, and MBP. Intracerebroventricular infusion of either the mineralocorticoid receptor antagonist RU-28318 or the AT(1)R antagonist losartan blocked aldosterone-induced phosphorylation of p44/42 MAPK and prevented the increases in RSNA, HR, and MBP. These data suggest that aldosterone-induced sympathetic excitation depends upon that AT(1)R-induced MAPK signaling in the brain. The short time course of this interaction suggests a nongenomic mechanism, perhaps via an aldosterone-induced transactivation of the AT(1)R as described in peripheral tissues.

  20. Mechanisms intrinsic to 5-HT2B receptor-induced potentiation of NMDA receptor responses in frog motoneurones.

    PubMed

    Holohean, Alice M; Hackman, John C

    2004-10-01

    In the presence of NMDA receptor open-channel blockers [Mg(2+); (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801); 1-amino-3,5-dimethyladamantane (memantine)] and TTX, high concentrations (30-100 microm) of either 5-hydroxytryptamine (5-HT) or alpha-methyl-5-hydroxytryptamine (alpha-Me-5-HT) significantly potentiated NMDA-induced depolarizations of frog spinal cord motoneurones. Potentiation was blocked by LY-53,857 (10-30 microm), SB 206553 (10 microm), and SB 204741 (30 microm), but not by spiroxatrine (10 microm), WAY 100,635 (1-30 microm), ketanserin (10 microm), RS 102221 (10 microm), or RS 39604 (10-20 microm). Therefore, alpha-Me-5-HT's facilitatory effects appear to involve 5-HT(2B) receptors. These effects were G-protein dependent as they were prevented by prior treatment with guanylyl-5'-imidodiphosphate (GMP-PNP, 100 microm) and H-Arg-Pro-Lys-Pro-Gln-Gln-D-Trp-Phe-D-Trp-D-Trp-Met-NH(2) (GP antagonist 2A, 3-6 microm), but not by pertussis toxin (PTX, 3-6 ng ml(-1), 48 h preincubation). This potentiation was not reduced by protein kinase C inhibition with staurosporine (2.0 microm), U73122 (10 microm) or N-(2-aminoethyl)-5-isoquinolinesulfonamide HCl (H9) (77 microm) or by intracellular Ca(2+) depletion with thapsigargin (0.1 microm) (which inhibits Ca(2+)/ATPase). Exposure of the spinal cord to the L-type Ca(2+) channel blockers nifedipine (10 microm), KN-62 (5 microm) or gallopamil (100 microm) eliminated alpha-Me-5-HT's effects. The calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphtalenesulfonamide (W7) (100 microm) diminished the potentiation. However, the calcium/calmodulin-dependent protein kinase II (CaM Kinase II) blocker KN-93 (10 microm) did not block the 5-HT enhancement of the NMDA responses. In summary, activation of 5-HT(2B) receptors by alpha-Me-5-HT facilitates NMDA-depolarizations of frog motoneurones via a G-protein, a rise in [Ca(2+)](i) from the entry of extracellular Ca(2+) through L-type Ca(2

  1. Adhesion-induced receptor segregation and adhesion plaque formation: A model membrane study.

    PubMed Central

    Kloboucek, A; Behrisch, A; Faix, J; Sackmann, E

    1999-01-01

    A model system to study the control of cell adhesion by receptor-mediated specific forces, universal interactions, and membrane elasticity is established. The plasma membrane is mimicked by reconstitution of homophilic receptor proteins into solid supported membranes and, together with lipopolymers, into giant vesicles with the polymers forming an artificial glycocalix. The homophilic cell adhesion molecule contact site A, a lipid-anchored glycoprotein from cells of the slime mold Dictyostelium discoideum, is used as receptor. The success of the reconstitution, the structure and the dynamics of the model membranes are studied by various techniques including film balance techniques, micro fluorescence, fluorescence recovery after photobleaching, electron microscopy, and phase contrast microscopy. The interaction of the functionalized giant vesicles with the supported bilayer is studied by reflection interference contrast microscopy, and the adhesion strength is evaluated quantitatively by a recently developed technique. At low receptor concentrations adhesion-induced receptor segregation in the membranes leads to decomposition of the contact zone between membranes into domains of strong (receptor-mediated) adhesion and regions of weak adhesion while continuous zones of strong adhesion form at high receptor densities. The adhesion strengths (measured in terms of the spreading pressure S) of the various states of adhesion are obtained locally by analysis of the vesicle contour near the contact line in terms of elastic boundary conditions of adhesion: the balance of tensions and moments. The spreading pressure of the weak adhesion zones is S approximately 10(-9) J/m(2) and is determined by the interplay of gravitation and undulation forces whereas the spreading pressure of the tight adhesion domains is of the order S approximately 10(-6) J/m(2). PMID:10512849

  2. Role of catecholamines and serotonin receptor subtypes in nefopam-induced antinociception.

    PubMed

    Girard, Philippe; Coppé, Marie-Claude; Verniers, Danielle; Pansart, Yannick; Gillardin, Jean-Marie

    2006-09-01

    The non-opiate analgesic nefopam has been shown to inhibit monoamines uptake, but little is known about receptor subtypes effectively involved in its analgesic effect. In vitro binding assays yielded the following measures of affinity (IC(50)): serotonergic 5-HT(2C) (1.4 microM), 5-HT(2A) (5.1 microM), 5-HT(3) (22.3 microM), 5-HT(1B) (41.7 microM), 5-HT(1A) (64.9 microM), adrenergic alpha(1) (15.0 microM) and dopaminergic D(1) (100 microM). Subcutaneous nefopam administration dose-dependently inhibited pain in acetic acid-induced writhing (1-30 mg kg(-1)) and formalin (1-10 mg kg(-1)) tests in the mouse. Pretreatments with adrenergic alpha(1) (prazosin) and alpha(2) (yohimbine), and serotonergic 5-HT(1B) (GR127935) receptor antagonists significantly increased the nefopam ED(50) in the writhing test. The serotonergic 5-HT(2C) (RS102221) and the dopaminergic D(2) (sulpiride) receptor antagonists inhibited nefopam antinociception in the formalin test. However, in both tests, nefopam analgesic activity was not modified by the following receptor antagonists: dopaminergic D(1) (SCH23390), serotonergic 5-HT(1A) (NAN-190, WAY100635), 5-HT(2A) (R96544, ketanserin), 5-HT(3) (tropisetron), and 5-HT(4) (SDZ205557). In conclusion, nefopam analgesic activity could be modulated by the adrenergic alpha(1) and alpha(2) receptors, the dopaminergic D(2) receptors, and the serotonergic 5-HT(1B) and 5-HT(2C) receptor subtypes.

  3. Autoimmune-induced glutamatergic receptor dysfunctions: conceptual and psychiatric practice implications.

    PubMed

    Rosenthal-Simons, Ayelet; Durrant, Andrea R; Heresco-Levy, Uriel

    2013-12-01

    Glutamatergic neurotransmission is mediated via complex receptorial systems including N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolpropionic acid (AMPA) and metabotropic receptor subtypes and plays a critical role in the modulation of synaptic plasticity, mood, cognitive processes and motor behavior. Glutamatergic function deficits are hypothesized to contribute to the pathogenesis of neuropsychiatric disorders, including schizophrenia, mood and movement disorders. Accumulating data are rapidly leading to the characterization of specific types of autoimmune encephalitis in which the receptors and proteins critically involved in glutamatergic neurotransmission, e.g., NMDA, AMPA receptors, are antigen targets. Characteristic of these syndromes, antibodies alter the structure and/or function of the corresponding neuronal antigen resulting in clinical pictures that resemble pharmacological disease models. Presently the best characterized autoimmune glutamatergic disorder is anti-NMDA receptor encephalitis. This disorder manifests with intertwined psychiatric and neurological features, defines a new syndrome, reclassifies poorly defined clinical states and extends previous hypotheses, such as hypo-NMDA receptor function in schizophrenia. The characterization of autoimmune-induced glutamatergic receptor dysfunctions (AGRD) is likely to have a substantial conceptual impact upon our understanding of neuropsychiatric disorders including schizophrenia, affective and movement dysfunctions. Further definition of AGRD will provide additional guidelines for psychiatric diagnoses, identification of homogeneous patient subtypes within broad phenomenological classifications and will contribute to the development of personalized treatments. The body of knowledge already accumulated on anti-NMDA receptor encephalitis highlights the need for wide dissemination of these concepts among psychiatrists, and in suspected cases, for early recognition, prompt clinical

  4. Cannabinoid CB2 receptor attenuates morphine-induced inflammatory responses in activated microglial cells

    PubMed Central

    Merighi, Stefania; Gessi, Stefania; Varani, Katia; Fazzi, Debora; Mirandola, Prisco; Borea, Pier Andrea

    2012-01-01

    BACKGROUND AND PURPOSE Among several pharmacological properties, analgesia is the most common feature shared by either opioid or cannabinoid systems. Cannabinoids and opioids are distinct drug classes that have been historically used separately or in combination to treat different pain states. In the present study, we characterized the signal transduction pathways mediated by cannabinoid CB2 and µ-opioid receptors in quiescent and LPS-stimulated murine microglial cells. EXPERIMENTAL APPROACH We examined the effects of µ-opioid and CB2 receptor stimulation on phosphorylation of MAPKs and Akt and on IL-1β, TNF-α, IL-6 and NO production in primary mouse microglial cells. KEY RESULTS Morphine enhanced release of the proinflammatory cytokines, IL-1β, TNF-α, IL-6, and of NO via µ-opioid receptor in activated microglial cells. In contrast, CB2 receptor stimulation attenuated morphine-induced microglial proinflammatory mediator increases, interfering with morphine action by acting on the Akt-ERK1/2 signalling pathway. CONCLUSIONS AND IMPLICATIONS Because glial activation opposes opioid analgesia and enhances opioid tolerance and dependence, we suggest that CB2 receptors, by inhibiting microglial activity, may be potential targets to increase clinical efficacy of opioids. PMID:22428664

  5. Dietary peptides induce satiety via cholecystokinin-A and peripheral opioid receptors in rats.

    PubMed

    Pupovac, Jelena; Anderson, G Harvey

    2002-09-01

    We hypothesized that the digestion of proteins gives rise to peptides that initiate several satiety signals from the gut, and that the signals arising will be dependent on the protein source. The role of peripheral opioid and cholecystokinin (CCK)-A receptors was investigated. Casein, soy protein, and casein and soy hydrolysates were administered to rats by gavage (0.5 g protein/4 mL water). Food intake was measured over 2 h. The opioid receptor antagonist, naloxone methiodide (1.0 mg/kg) given intraperitoneally (i.p.), increased food intake when given at the same time as the hydrolysate preloads, 25 min after the casein preloads and 55 min after the soy protein preloads. The CCK-A receptor antagonist, devazepide (which reverses protein-induced food intake suppression), when given at 0.25 mg/kg, i.p., 60 min before preloads of each of three soy hydrolysates, also blocked suppression of food intake, but the strength and duration of the interaction depended on the preparation. When the two receptor antagonists were both administered with soy or casein preloads, their effects were additive. We conclude that peptides arising from digestion contribute to satiety by independent activation of both opioid and CCK-A receptors.

  6. Tamoxifen counteracts estradiol induced effects on striatal and hypophyseal dopamine receptors

    SciTech Connect

    Ferretti, C.; Blengio, M.; Ghi, P.; Racca, S.; Genazzani, E.; Portaleone, P.

    1988-01-01

    We investigated the ability of Tamoxifen (TAM), an antiestrogen drug, to counteract the modification induced by estrogens on dopamine (DA) receptors on striatum and on adenohypophysis of ovex female rats. Subacute treatment with 17..beta..-estradiol (E/sub 2/) at both low (0.1 ..mu..g/kg) and high (20 ..mu..g/kg) doses confirmed its ability to increase the number of striatal /sup 3/H-Spiperone (/sup 3/H-SPI) binding sites in a dose dependent manner. By contrast in the pituitary, only high doses of estrogen were effective in reducing the number of DA receptors. We treated ovex female rats for 15 days with TAM alone or associated with E/sub 2/, to see if these estrogenic effects could be suppressed by an antiestrogenic drug. TAM did not affect the number of striatal DA receptors, but significantly increased the adenohypophy-seal DA binding sites, without varying their affinity. No changes were observed in pituitary and striatal DA receptor density, even when TAM was injected in association with estradiol. In conclusions: TAM is able to counteract the effects estrogens have on DA receptors. However there is some evidence that it could influence the pituitary DA systems independently of it antiestrogenic activity.

  7. Ethanol-induced GABAA receptor alpha4 subunit plasticity involves phosphorylation and neuroactive steroids.

    PubMed

    Werner, David F; Porcu, Patrizia; Boyd, Kevin N; O'Buckley, Todd K; Carter, Jenna M; Kumar, Sandeep; Morrow, A Leslie

    2016-04-01

    GABAA receptors containing α4 subunits are widely implicated in acute ethanol sensitivity, and their spatial and temporal regulation prominently contributes to ethanol-induced neuroplasticity in hippocampus and cortex. However, it is unknown if α4-containing GABAA receptors in the thalamus, an area of high α4 expression, display similar regulatory patterns following ethanol administration, and if so, by which molecular mechanisms. In the current study, thalamic GABAA receptor α4 subunit levels were increased following a 6-week-, but not a 2-week chronic ethanol diet. Following acute high-dose ethanol administration, thalamic GABAA receptor α4 subunit levels were regulated in a temporal fashion, as a decrease was observed at 2h followed by a delayed transient increase. PKCγ and PKCδ levels paralleled α4 temporal expression patterns following ethanol exposure. Initial decreases in α4 subunit expression were associated with reduced serine phosphorylation. Delayed increases in expression were not associated with a change in phosphorylation state, but were prevented by inhibiting neuroactive steroid production with the 5α-reductase inhibitor finasteride. Overall, these studies indicate that thalamic GABAA receptor α4 subunit expression following acute and chronic ethanol administration exhibits similar regulatory patterns as other regions and that transient expression patterns following acute exposure in vivo are likely dependent on both subunit phosphorylation state and neuroactive steroids.

  8. The role of P2X7 receptors in a rodent PCP-induced schizophrenia model

    PubMed Central

    Koványi, Bence; Csölle, Cecilia; Calovi, Stefano; Hanuska, Adrienn; Kató, Erzsébet; Köles, László; Bhattacharya, Anindya; Haller, József; Sperlágh, Beáta

    2016-01-01

    P2X7 receptors (P2X7Rs) are ligand-gated ion channels sensitive to extracellular ATP. Here we examined for the first time the role of P2X7R in an animal model of schizophrenia. Using the PCP induced schizophrenia model we show that both genetic deletion and pharmacological inhibition of P2X7Rs alleviate schizophrenia-like behavioral alterations. In P2rx7+/+ mice, PCP induced hyperlocomotion, stereotype behavior, ataxia and social withdrawal. In P2X7 receptor deficient mice (P2rx7−/−), the social interactions were increased, whereas the PCP induced hyperlocomotion and stereotype behavior were alleviated. The selective P2X7 receptor antagonist JNJ-47965567 partly replicated the effect of gene deficiency on PCP-induced behavioral changes and counteracted PCP-induced social withdrawal. We also show that PCP treatment upregulates and increases the functional responsiveness of P2X7Rs in the prefrontal cortex of young adult animals. The amplitude of NMDA evoked currents recorded from layer V pyramidal neurons of cortical slices were slightly decreased by both genetic deletion of P2rx7 and by JNJ-47965567. PCP induced alterations in mRNA expression encoding schizophrenia-related genes, such as NR2A, NR2B, neuregulin 1, NR1 and GABA α1 subunit were absent in the PFC of young adult P2rx7−/− animals. Our findings point to P2X7R as a potential therapeutic target in schizophrenia. PMID:27824163

  9. Triphenyl phosphate-induced developmental toxicity in zebrafish: Potential role of the retinoic acid receptor

    PubMed Central

    Isales, Gregory M.; Hipszer, Rachel A.; Raftery, Tara D.; Chen, Albert; Stapleton, Heather M.; Volz, David C.

    2015-01-01

    Using zebrafish as a model, we previously reported that developmental exposure to triphenyl phosphate (TPP) – a high-production volume organophosphate-based flame retardant – results in dioxin-like cardiac looping impairments that are independent of the aryl hydrocarbon receptor. Using a pharmacologic approach, the objective of this study was to investigate the potential role of retinoic acid receptor (RAR) – a nuclear receptor that regulates vertebrate heart morphogenesis – in mediating TPP-induced developmental toxicity in zebrafish. We first revealed that static exposure of zebrafish from 5-72 hours post-fertilization (hpf) to TPP in the presence of non-toxic concentrations of an RAR antagonist (BMS493) significantly enhanced TPP-induced toxicity (relative to TPP alone), even though identical non-toxic BMS493 concentrations mitigated retinoic acid (RA)-induced toxicity. BMS493-mediated enhancement of TPP toxicity was not a result of differential TPP uptake or metabolism, as internal embryonic doses of TPP and diphenyl phosphate (DPP) – a primary TPP metabolite - were not different in the presence or absence of BMS493. Using real-time PCR, we then quantified the relative change in expression of cytochrome P450 26a1 (cyp26a1) – a major target gene for RA-induced RAR activation in zebrafish – and found that RA and TPP exposure resulted in a ∼5-fold increase and decrease in cyp26a1 expression, respectively, relative to vehicle-exposed embryos. To address whether TPP may interact with human RARs, we then exposed Chinese hamster ovary cells stably transfected with chimeric human RARα-, RARβ-, or RARγ to TPP in the presence of RA, and found that TPP significantly inhibited RA-induced luciferase activity in a concentration-dependent manner. Overall, our findings suggest that zebrafish RARs may be involved in mediating TPP-induced developmental toxicity, a mechanism of action that may have relevance to humans. PMID:25725299

  10. [Epidermal growth factor receptor expression and epidermal growth factor blood plasma content in simple and complex endometrial hyperplasia].

    PubMed

    Dznelashvili, N; Kasradze, D; Tavartkiladze, A; Mariamidze, A

    2014-01-01

    The goal of our study was to concurrently determine the prognostic significance of Epidermal Growth Factor Receptor (EGFR) expression in endometrium and Epidermal Growth Factor (EGF) blood content in simple and complex hyperplasia. In order to detect EGFR expression, immunohistochemical examination of endometrial scarp from 35 patients was done along with HPLC (High performance liquid chromatography) method, for measuring EGF blood plasma content. The numerical data obtained were processed statistically using computer program SPSS-12. According to the results: 1. A significant/marked increase in EGF blood plasma level together with pronounced EGFR expression in simple endometrial hyperplasia (without atypia) suggests that simple hyperplasia is likely to transform into complex form, while unchanged level of EGF against the background of mild EGFR expression is probably indicative of not very bad prognosis. 2. Normal indices of EGF blood plasma level in simple endometrial hyperplasia (without atypia), accompanied by mild EGFR expression is suggestive of good prognosis. 3. A sharp or extremely sharp increase in EGF blood plasma level with pronounced EGFR expression in complex endometrial hyperplasia (without atypia) is likely to indicate poor prognosis that may lead to the transformation into atypical form. However, unchanged EGF blood plasma level against the background of mild EGFR expression in complex endometrial hyperplasia (without atypia) is likely to point to not very bad prognosis. 4. A marked increase in EGF blood plasma level with a pronounced EGFR expression in complex endometrial hyperplasia (without atypia) is likely to indicate poor prognosis that may lead to the transformation into atypical form. Because it is evident that drastic increase in EGF blood plasma level is not necessary, other factor should be suspected to play the major role, i.e the substance that will (or will not) withstand neoplasia.

  11. Contribution of peripheral vanilloid receptor to the nociception induced by injection of spermine in mice.

    PubMed

    Gewehr, Camila; da Silva, Mariane Arnoldi; dos Santos, Gabriela Trevisan; Rossato, Mateus Fortes; de Oliveira, Sara Marchesan; Drewes, Carine Cristiane; Pazini, Andréia Martini; Guerra, Gustavo Petri; Rubin, Maribel A; Ferreira, Juliano

    2011-10-01

    Polyamines (putrescine, spermidine and spermine) are important endogenous regulators of ion channels, such as vanilloid (TRPV1), glutamatergic (NMDA or AMPA/kainate) and acid-sensitive (ASIC) receptors. In the present study, we have investigated the possible nociceptive effect induced by polyamines and the mechanisms involved in this nociception in vivo. The subcutaneous (s.c.) injection of capsaicin (as positive control), spermine, spermidine or putrescine produced nociception with ED(50) of 0.16 (0.07-0.39)nmol/paw, 0.4 (0.2-0.7) μmol/paw, 0.3 (0.1-0.9) μmol/paw and 3.2 (0.9-11.5) μmol/paw, respectively. The antagonists of NMDA (MK801, 1 nmol/paw), AMPA/kainate (DNQX, 1 nmol/paw) or ASIC receptors (amiloride, 100 nmol/paw) failed to reduce the spermine-trigged nociception. However, the TRPV1 antagonists capsazepine or SB366791 (1 nmol/paw) reduced spermine-induced nociception, with inhibition of 81 ± 10 and 68 ± 9%, respectively. The previous desensitization with resiniferatoxin (RTX) largely reduced the spermine-induced nociception and TRPV1 expression in the sciatic nerve, with reductions of 82 ± 9% and 67 ± 11%, respectively. Furthermore, the combination of spermine (100 nmol/paw) and RTX (0.005 fmol/paw), in doses which alone were not capable of inducing nociception, produced nociceptive behaviors. Moreover, different concentrations of spermine (3-300 μM) enhanced the specific binding of [(3)H]-RTX to TRPV1 receptor. Altogether, polyamines produce spontaneous nociceptive effect through the stimulation of TRPV1, but not of ionotropic glutamate or ASIC receptors.

  12. Correlation between the expression of divalent metal transporter 1 and the content of hypoxia-inducible factor-1 in hypoxic HepG2 cells

    PubMed Central

    Li, Zhu; Lai, Zhang; Ya, Ke; Fang, Du; Ho, Yung Wing; Lei, Yang; Ming, Qian Zhong

    2008-01-01

    Abstract Transferrin and transferrin receptor are two key proteins of iron metabolism that have been identified to be hypoxia-inducible genes. Divalent metal transporter 1 (DMT1) is also a key transporter of iron under physiological conditions. In addition, in the 5′ regulatory region of human DMT1 (between −412 and −570), there are two motifs (CCAAAGTGCTGGG) that are similar to hypoxia-inducible factor-1 (HIF-1) binding sites. It was therefore speculated that DMT1 might also be a hypoxia-inducible gene. We investigated the effects of hypoxia and hypoxia/re-oxygenation on the expression of DMT1 and the content of HIF-1alpha in HepG2 cells. As we expected, a very similar tendency in the responses of the expression of HIF-1α, DMT1+IRE (iron response element) and DMT1−IRE proteins to chemical (CoCl2) or physical hypoxia was observed. A highly significant correlation was found between the expression of DMT1 proteins and the contents of HIF-1 in hypoxic cells. After the cells were exposed to hypoxia and subsequent normoxia, no HIF-1α could be detected and a significant decrease in DMT1+IRE expression (P<0.05), but not in DMT1−IRE protein (versus the hypoxia group), was observed. The findings implied that the HIF-1 pathway might have a role in the regulation of DMT1+IRE expression during hypoxia. PMID:18419598

  13. Vitamin D3 restores altered cholinergic and insulin receptor expression in the cerebral cortex and muscarinic M3 receptor expression in pancreatic islets of streptozotocin induced diabetic rats.

    PubMed

    Kumar, Peeyush T; Antony, Sherin; Nandhu, Mohan S; Sadanandan, Jayanarayanan; Naijil, George; Paulose, Chiramadathikudiyil S

    2011-05-01

    Nutritional therapy is a challenging but necessary dimension in the management of diabetes and neurodegenerative changes associated with it. The study evaluates the effect of vitamin D(3) in preventing the altered function of cholinergic, insulin receptors and GLUT3 in the cerebral cortex of diabetic rats. Muscarinic M3 acetylcholine receptors in pancreas control insulin secretion. Vitamin D(3) treatment in M3 receptor regulation in the pancreatic islets was also studied. Radioreceptor binding assays and gene expression was done in the cerebral cortex of male Wistar rats. Immunocytochemistry of muscarinic M3 receptor was studied in the pancreatic islets using specific antibodies. Y-maze was used to evaluate the exploratory and spatial memory. Diabetes induced a decrease in muscarinic M1, insulin and vitamin D receptor expression and an increase in muscarinic M3, α7 nicotinic acetylcholine receptor, acetylcholine esterase and GLUT3 expression. Vitamin D(3) and insulin treatment reversed diabetes-induced alterations to near control. Diabetic rats showed a decreased Y-maze performance while vitamin D(3) supplementation improved the behavioural deficit. In conclusion, vitamin D(3) shows a potential therapeutic effect in normalizing diabetes-induced alterations in cholinergic, insulin and vitamin D receptor and maintains a normal glucose transport and utilisation in the cortex. In addition vitamin D(3) modulated muscarinic M3 receptors activity in pancreas and plays a pivotal role in controlling insulin secretion. Hence our findings proved, vitamin D(3) supplementation as a potential nutritional therapy in ameliorating diabetes mediated cortical dysfunctions and suggest an interaction between vitamin D(3) and muscarinic M3 receptors in regulating insulin secretion from pancreas.

  14. Ligand-induced internalization, recycling, and resensitization of adrenomedullin receptors depend not on CLR or RAMP alone but on the receptor complex as a whole.

    PubMed

    Nag, Kakon; Sultana, Naznin; Kato, Akira; Dranik, Anna; Nakamura, Nobuhiro; Kutsuzawa, Koichi; Hirose, Shigehisa; Akaike, Toshihiro

    2015-02-01

    Adrenomedullins (AM) is a multifaceted distinct subfamily of peptides that belongs to the calcitonin gene-related peptide (CGRP) superfamily. These peptides exert their functional activities via associations of calcitonin receptor-like receptors (CLRs) and receptor activity-modifying proteins (RAMPs) RAMP2 and RAMP3. Recent studies established that RAMPs and CLRs can modify biochemical properties such as trafficking and glycosylation of each other. However there is very little or no understanding regarding how RAMP or CLR influence ligand-induced events of AM-receptor complex. In this study, using pufferfish homologs of CLR (mfCLR1-3) and RAMP (mfRAMP2 and mfRAMP3), we revealed that all combinations of CLR and RAMP quickly underwent ligand-induced internalization; however, their recycling rates were different as follows: mfCLR1-mfRAMP3>mfCLR2-mfRAMP3>mfCLR3-mfRAMP3. Functional receptor assay confirmed that the recycled receptors were resensitized on the plasma membrane. In contrast, a negligible amount of mfCLR1-mfRAMP2 was recycled and reconstituted. Immunocytochemistry results indicated that the lower recovery rate of mfCLR3-mfRAMP3 and mfCLR1-mfRAMP2 was correlated with higher proportion of lysosomal localization of these receptor complexes compared to the other combinations. Collectively our results indicate, for the first time, that the ligand-induced internalization, recycling, and reconstitution properties of RAMP-CLR receptor complexes depend on the receptor-complex as a whole, and not on individual CLR or RAMP alone.

  15. High Content Analysis of Human Pluripotent Stem Cell Derived Hepatocytes Reveals Drug Induced Steatosis and Phospholipidosis

    PubMed Central

    Pradip, Arvind; Steel, Daniella; Jacobsson, Susanna; Holmgren, Gustav; Ingelman-Sundberg, Magnus; Sartipy, Peter; Björquist, Petter; Johansson, Inger; Edsbagge, Josefina

    2016-01-01

    Hepatotoxicity is one of the most cited reasons for withdrawal of approved drugs from the market. The use of nonclinically relevant in vitro and in vivo testing systems contributes to the high attrition rates. Recent advances in differentiating human induced pluripotent stem cells (hiPSCs) into pure cultures of hepatocyte-like cells expressing functional drug metabolizing enzymes open up possibilities for novel, more relevant human cell based toxicity models. The present study aimed to investigate the use of hiPSC derived hepatocytes for conducting mechanistic toxicity testing by image based high content analysis (HCA). The hiPSC derived hepatocytes were exposed to drugs known to cause hepatotoxicity through steatosis and phospholipidosis, measuring several endpoints representing different mechanisms involved in drug induced hepatotoxicity. The hiPSC derived hepatocytes were benchmarked to the HepG2 cell line and generated robust HCA data with low imprecision between plates and batches. The different parameters measured were detected at subcytotoxic concentrations and the order of which the compounds were categorized (as severe, moderate, mild, or nontoxic) based on the degree of injury at isomolar concentration corresponded to previously published data. Taken together, the present study shows how hiPSC derived hepatocytes can be used as a platform for screening drug induced hepatotoxicity by HCA. PMID:26880940

  16. Taurine prevents ammonia-induced accumulation of cyclic GMP in rat striatum by interaction with GABAA and glycine receptors.

    PubMed

    Hilgier, Wojciech; Oja, Simo S; Saransaari, Pirjo; Albrecht, Jan

    2005-05-10

    Previously, we had shown that ammonium chloride (ammonia)-induced accumulation of cyclic GMP in the microdialysates of rat striatum is blocked by taurine. In this study, coinfusion with taurine of a GABAA receptor antagonist bicuculline or a glycine receptor antagonist strychnine (100 microM each), separately, restored ammonia-induced release of cGMP to the extracellular fluid to approximately 29% and 18% of the level measured in the absence of taurine, respectively. Simultaneous coinfusion of both antagonists or of 100 muM picrotoxin, which is an antagonist of both GABAA and Gly receptors, offsets most of the taurine block. Ammonia-induced accumulation of cyclic GMP was attenuated by approximately 12% upon coinfusion of a GABAA receptor agonist muscimol (100 microM). The results suggest that stimulation of both GABAA and glycine receptors is involved in the mechanism by which taurine limits the activation of the NMDA/NO/cGMP pathway by ammonia in the striatum.

  17. sPLA2 IB induces human podocyte apoptosis via the M-type phospholipase A2 receptor.

    PubMed

    Pan, Yangbin; Wan, Jianxin; Liu, Yipeng; Yang, Qian; Liang, Wei; Singhal, Pravin C; Saleem, Moin A; Ding, Guohua

    2014-10-22

    The M-type phospholipase A2 receptor (PLA2R) is expressed in podocytes in human glomeruli. Group IB secretory phospholipase A2 (sPLA2 IB), which is one of the ligands of the PLA2R, is more highly expressed in chronic renal failure patients than in controls. However, the roles of the PLA2R and sPLA2 IB in the pathogenesis of glomerular diseases are unknown. In the present study, we found that more podocyte apoptosis occurs in the kidneys of patients with higher PLA2R and serum sPLA2 IB levels. In vitro, we demonstrated that human podocyte cells expressed the PLA2R in the cell membrane. After binding with the PLA2R, sPLA2 IB induced podocyte apoptosis in a time- and concentration-dependent manner. sPLA2 IB-induced podocyte PLA2R upregulation was not only associated with increased ERK1/2 and cPLA2α phosphorylation but also displayed enhanced apoptosis. In contrast, PLA2R-silenced human podocytes displayed attenuated apoptosis. sPLA2 IB enhanced podocyte arachidonic acid (AA) content in a dose-dependent manner. These data indicate that sPLA2 IB has the potential to induce human podocyte apoptosis via binding to the PLA2R. The sPLA2 IB-PLA2R interaction stimulated podocyte apoptosis through activating ERK1/2 and cPLA2α and through increasing the podocyte AA content.

  18. 5-HT3 receptors antagonists reduce serotonin-induced scratching in mice.

    PubMed

    Ostadhadi, Sattar; Kordjazy, Nastaran; Haj-Mirzaian, Arya; Mansouri, Parvin; Dehpour, Ahmad Reza

    2015-06-01

    Serotonin (5-hydroxytryptamine, 5-HT) acts as a pruritogen in humans and animals, but the mechanisms of action through that serotonin induces itch response have not been extensively discovered. In our study, we attempted to investigate the role of 5-HT3 receptors in scratching behavior due to intradermal serotonin injection. Intradermal injection of serotonin (14.1-235 nmol/site) into the nape of the neck of mice was performed to elicit itch. Scratching behavior was evaluated by measuring the number of bouts during 60 min after injection. We evaluated the effect of intraperitoneal pretreatment with ondansetron and tropisetron (0.1, 0.3, and 1 mg/kg) on itch induced by serotonin. Also, intradermal ondansetron and tropisetron at doses 50, 100, and 200 nmol/site were concurrently administrated with serotonin. Serotonin produced a significant enhancement in scratching at dose 141 nmol/site. Concurrent administration of ondansetron (50, 100, and 200 nmol/site) and tropisetron (100 and 200 nmol/site) with serotonin reduced scratching activity compared to the animals that only received serotonin. Also, pretreatment with intraperitoneal ondansetron and tropisetron (0.3 and 1 mg/kg) 30 min before serotonin attenuated the itch response. We showed that the scratching induced by intradermal serotonin is mediated by 5-HT3 receptors subtype. It can be concluded that 5-HT3 may play a role in mediating serotonin-associated itch responses, and we introduce 5-HT3 receptors as possible targets for antipruritic agents.

  19. Fenugreek induced apoptosis in breast cancer MCF-7 cells mediated independently by fas receptor change.

    PubMed

    Alshatwi, Ali Abdullah; Shafi, Gowhar; Hasan, Tarique Noorul; Syed, Naveed Ahmed; Khoja, Kholoud Khalid

    2013-01-01

    Trigonella foenum in graecum (Fenugreek) is a traditional herbal plant used to treat disorders like diabetes, high cholesterol, wounds, inflammation, gastrointestinal ailments, and it is believed to have anti-tumor properties, although the mechanisms for the activity remain to be elucidated. In this study, we prepared a methanol extract from Fenugreek whole plants and investigated the mechanism involved in its growth-inhibitory effect on MCF- 7 human breast cancer cells. Apoptosis of MCF-7 cells was evidenced by investigating trypan blue exclusion, TUNEL and Caspase 3, 8, 9, p53, FADD, Bax and Bak by real-time PCR assays inducing activities, in the presence of FME at 65 μg/mL for 24 and 48 hours. FME induced apoptosis was mediated by the death receptor pathway as demonstrated by the increased level of Fas receptor expression after FME treatment. However, such change was found to be absent in Caspase 3, 8, 9, p53, FADD, Bax and Bak, which was confirmed by a time-dependent and dose-dependent manner. In summary, these data demonstrate that at least 90% of FME induced apoptosis in breast cell is mediated by Fas receptor-independently of either FADD, Caspase 8 or 3, as well as p53 interdependently.

  20. Cortisol Induces Reactive Oxygen Species Through a Membrane Glucocorticoid Receptor in Rainbow Trout Myotubes.

    PubMed

    Espinoza, Marlen B; Aedo, Jorge E; Zuloaga, Rodrigo; Valenzuela, Cristian; Molina, Alfredo; Valdés, Juan A

    2017-04-01

    Cortisol is an essential regulator of neuroendocrine stress responses in teleosts. Cortisol predominantly affects target tissues through the genomic pathway, which involves interacting with cytoplasmic glucocorticoid receptors, and thereby, modulating stress-response gene expressions. Cortisol also produces rapid effects via non-genomic pathways, which do not involve gene transcription. Although cortisol-mediated genomic pathways are well documented in teleosts, non-genomic pathways are not fully understood. Moreover, no studies have focused on the contribution of non-genomic cortisol pathways in compensatory stress responses in fish. In this study, rainbow trout (Oncorhynchus mykiss) skeletal myotubes were stimulated with physiological concentrations of cortisol and cortisol-BSA, a membrane-impermeable agent, resulting in an early induction of reactive oxygen species (ROS). This production was not suppressed by transcription or translation inhibitors, suggesting non-genomic pathway involvement. Moreover, myotube preincubation with RU486 and NAC completely suppressed cortisol- and cortisol-BSA-induced ROS production. Subcellular fractionation analysis revealed the presence of cell membrane glucocorticoid receptors. Finally, cortisol-BSA induced a significant increase in ERK1/2 and CREB phosphorylation, as well as in CREB-dependent transcriptional activation of the pgc1a gene expression. The obtained results strongly suggest that cortisol acts through a non-genomic glucocorticoid receptor-mediated pathway to induce ROS production and contribute to ERK/CREB/PGC1-α signaling pathway activation as stress compensation mechanisms. J. Cell. Biochem. 118: 718-725, 2017. © 2016 Wiley Periodicals, Inc.

  1. Coxsackievirus B3 induces viral myocarditis by upregulating toll-like receptor 4 expression.

    PubMed

    Zhao, Zhao; Cai, Tian-Zhi; Lu, Yan; Liu, Wen-Jun; Cheng, Man-Li; Ji, Yu-Qiang

    2015-04-01

    In the present study, we investigated the potential pathogenesis of coxsackievirus B3 (CVB3)-induced viral myocarditis and the promising protective effect of silencing RNA (small interfering RNA, siRNA). One hundred and twenty mice were included in the study, and 30 mice were intraperitoneally inoculated with CVB3 to establish an acute viral myocarditis model. The survival rate was observed for the CVB3-infected mouse model (MOD), and myocardial injury was examined by HE (hematoxylin and eosin) staining assay. Real-time PCR (RT-PCR) and Western blot assay were selected to detect the toll-like receptor 4 (TLR4) expression in myocardial tissues. The TLR4 gene was silenced for the MOD mice, and the effects of this treatment were observed. The results indicate that the expression of TLR4 mRNA and the protein significantly and persistently increased during the progression of CVB3-induced myocarditis. The activities of cardiac enzymes including CK, LDH, AST, and CK-MB were also enhanced in CVB3-induced myocardial tissues. Interestingly, when the TLR4 gene was silenced, the CVB3-induced TLR4 production was significantly decreased and the severity of myocarditis was significantly lessened. In conclusion, CVB3 may induce viral myocarditis by upregulating toll-like receptor 4 expression. The viral myocarditis can be ameliorated by silencing the TLR4 gene in the CVB3 viral myocarditis model, which may be a feasible therapeutic method for treatment of viral myocarditis.

  2. Pharmacologic Antagonism of Ghrelin Receptors Attenuates Development of Nicotine Induced Locomotor Sensitization in Rats

    PubMed Central

    Wellman, Paul J.; Clifford, P. Shane; Rodriguez, Juan; Hughes, Samuel; Eitan, Shoshana; Brunel, Luc; Fehrentz, Jean-Alain; Martinez, Jean

    2011-01-01

    Aims Ghrelin (GHR) is an orexigenic gut peptide that interacts with ghrelin receptors (GHR-Rs) to modulate brain reinforcement circuits. Systemic GHR infusions augment cocaine stimulated locomotion and conditioned place preference (CPP) in rats, whereas genetic or pharmacological ablation of GHR-Rs has been shown to attenuate the acute locomotor-enhancing effects of nicotine, cocaine, amphetamine and alcohol and to blunt the CPP induced by food, alcohol, amphetamine and cocaine in mice. The stimulant nicotine can induce CPP and like amphetamine and cocaine, repeated administration of nicotine induces locomotor sensitization in rats. A key issue is whether pharmacological antagonism of GHR-Rs would similarly attenuate nicotine-induced locomotor sensitization. Method To examine the role of GHR-Rs in the behavioral sensitizing effects of nicotine, adult male rats were injected with either 0, 3 or 6 mg/kg of the GHR-R receptor antagonist JMV 2959 (i.p.) and 20 minutes later with either vehicle or 0.4 mg/kg nicotine hydrogen tartrate (s.c.) on each of 7 consecutive days. Results Rats treated with nicotine alone showed robust locomotor sensitization, whereas rats pretreated with JMV 2959 showed significantly attenuated nicotine-induced hyperlocomotion. Conclusions These results suggest that GHR-R activity is required for the induction of locomotor sensitization to nicotine and complement an emerging literature implicating central GHR systems in drug reward/reinforcement. PMID:21903141

  3. Angiotensin receptor blockade attenuates cigarette smoke-induced lung injury and rescues lung architecture in mice.

    PubMed

    Podowski, Megan; Calvi, Carla; Metzger, Shana; Misono, Kaori; Poonyagariyagorn, Hataya; Lopez-Mercado, Armando; Ku, Therese; Lauer, Thomas; McGrath-Morrow, Sharon; Berger, Alan; Cheadle, Christopher; Tuder, Rubin; Dietz, Harry C; Mitzner, Wayne; Wise, Robert; Neptune, Enid

    2012-01-01

    Chronic obstructive pulmonary disease (COPD) is a prevalent smoking-related disease for which no disease-altering therapies currently exist. As dysregulated TGF-β signaling associates with lung pathology in patients with COPD and in animal models of lung injury induced by chronic exposure to cigarette smoke (CS), we postulated that inhibiting TGF-β signaling would protect against CS-induced lung injury. We first confirmed that TGF-β signaling was induced in the lungs of mice chronically exposed to CS as well as in COPD patient samples. Importantly, key pathological features of smoking-associated lung disease in patients, e.g., alveolar injury with overt emphysema and airway epithelial hyperplasia with fibrosis, accompanied CS-induced alveolar cell apoptosis caused by enhanced TGF-β signaling in CS-exposed mice. Systemic administration of a TGF-β-specific neutralizing antibody normalized TGF-β signaling and alveolar cell death, conferring improved lung architecture and lung mechanics in CS-exposed mice. Use of losartan, an angiotensin receptor type 1 blocker used widely in the clinic and known to antagonize TGF-β signaling, also improved oxidative stress, inflammation, metalloprotease activation and elastin remodeling. These data support our hypothesis that inhibition of TGF-β signaling through angiotensin receptor blockade can attenuate CS-induced lung injury in an established murine model. More importantly, our findings provide a preclinical platform for the development of other TGF-β-targeted therapies for patients with COPD.

  4. Multiscale features including water content of polymer-induced kaolinite floc structures

    NASA Astrophysics Data System (ADS)

    Sharma, Sugandha

    Despite their many uses, fine clay particles such as kaolinite are a nuisance in management of tailings in various industries such as the oil sands and phosphate processing industry. The effective flocculation, sedimentation, and consolidation of these fine particles are a major challenge. In industries, polymers are added to tailings suspension to facilitate formation and eventual sedimentation of flocs. The structure of floc and the water entrapped within the floc determine floc behavior and settling characteristics. The quantification of water entrapped within the kaolinite flocs has not been reported before. The information on kaolinite floc size and shape is also limited due to the challenges in experimental procedures for these delicate structures. In this thesis research, operating conditions for kaolinite flocculation were determined and a suitable polymer was chosen by settling experiments. Further investigation of the floc formed was done in suspended state as well as in sedimented state. The flocs were analyzed for their size, shape, water content, and microstructure. A pool of analytical techniques like the Particle Vision & Measurement (PVM), Dynamic Image Analysis (DIA), Scanning Electron Microscopy (SEM), High Resolution X-ray Microtomography (HRXMT), and image processing software like Fiji, Medical Image Processing Analysis & Visualization (MIPAV), and Drishti were used. The analysis of suspended flocs by PVM and DIA revealed a mean floc size of about 225 microm for high molecular weight, 5% anionic polyacrylamide-induced flocs. The low molecular weight, 70% cationic polymer-induced flocs were found to be smaller in size (145 microm). DIA was used to analyze the flocs at different solid concentration. It was found that the increase in solid concentration leads to increase in floc size. Floc circularity was also analyzed by using both these methods. Most flocs were irregular in shape with circularity ranging between 0.2-0.3. However, the circularity

  5. Chronic methamphetamine treatment induces oxytocin receptor up-regulation in the amygdala and hypothalamus via an adenosine A2A receptor-independent mechanism.

    PubMed

    Zanos, Panos; Wright, Sherie R; Georgiou, Polymnia; Yoo, Ji Hoon; Ledent, Catherine; Hourani, Susanna M; Kitchen, Ian; Winsky-Sommerer, Raphaelle; Bailey, Alexis

    2014-04-01

    There is mounting evidence that the neuropeptide oxytocin is a possible candidate for the treatment of drug addiction. Oxytocin was shown to reduce methamphetamine self-administration, conditioned place-preference, hyperactivity and reinstatement in rodents, highlighting its potential for the management of methamphetamine addiction. Thus, we hypothesised that the central endogenous oxytocinergic system is dysregulated following chronic methamphetamine administration. We tested this hypothesis by examining the effect of chronic methamphetamine administration on oxytocin receptor density in mice brains with the use of quantitative receptor autoradiographic binding. Saline (4ml/kg/day, i.p.) or methamphetamine (1mg/kg/day, i.p.) was administered daily for 10 days to male, CD1 mice. Quantitative autoradiographic mapping of oxytocin receptors was carried out with the use of [(125)I]-vasotocin in brain sections of these animals. Chronic methamphetamine administration induced a region specific upregulation of oxytocin receptor density in the amygdala and hypothalamus, but not in the nucleus accumbens and caudate putamen. As there is evidence suggesting an involvement of central adenosine A2A receptors on central endogenous oxytocinergic function, we investigated whether these methamphetamine-induced oxytocinergic neuroadaptations are mediated via an A2A receptor-dependent mechanism. To test this hypothesis, autoradiographic oxytocin receptor binding was carried out in brain sections of male CD1 mice lacking A2A receptors which were chronically treated with methamphetamine (1mg/kg/day, i.p. for 10 days) or saline. Similar to wild-type animals, chronic methamphetamine administration induced a region-specific upregulation of oxytocin receptor binding in the amygdala and hypothalamus of A2A receptor knockout mice and no genotype effect was observed. These results indicate that chronic methamphetamine use can induce profound neuroadaptations of the oxytocinergic receptor

  6. Ethanol-Induced Motor Impairment Mediated by Inhibition of α7 Nicotinic Receptors

    PubMed Central

    McDaid, John; Abburi, Chandrika; Wolfman, Shannon L.; Gallagher, Keith

    2016-01-01

    Nicotine and ethanol (EtOH) are among the most widely co-abused substances, and nicotinic acetylcholine receptors (nAChRs) contribute to the behavioral effects of both drugs. Along with their role in addiction, nAChRs also contribute to motor control circuitry. The α7 nAChR subtype is highly expressed in the laterodorsal tegmental nucleus (LDTg), a brainstem cholinergic center that contributes to motor performance through its projections to thalamic motor relay centers, including the mediodorsal thalamus. We demonstrate that EtOH concentrations just above the legal limits for intoxication in humans can inhibit α7 nAChRs in LDTg neurons from rats. This EtOH-induced inhibition is mediated by a decrease in cAMP/PKA signaling. The α7 nAChR-positive allosteric modulator PNU120596 [N-(5-chloro-2,4-dimethoxyphenyl)-N′-(5-methyl-3-isoxazolyl)-urea], which interferes with receptor desensitization, completely eliminated EtOH modulation of these receptors. These data suggest that EtOH inhibits α7 responses through a PKA-dependent enhancement of receptor desensitization. EtOH also inhibited the effects of nicotine at presynaptic α7 nAChRs on glutamate terminals in the mediodorsal thalamus. In vivo administration of PNU120596 either into the cerebral ventricles or directly into the mediodorsal thalamus attenuated EtOH-induced motor impairment. Thus, α7 nAChRs are likely important mediators of the motor impairing effects of moderate EtOH consumption. SIGNIFICANCE STATEMENT The motor-impairing effects of ethanol contribute to intoxication-related injury and death. Here we explore the cellular and neural circuit mechanisms underlying ethanol-induced motor impairment. Physiologically relevant concentrations of ethanol inhibit activity of a nicotinic receptor subtype that is expressed in brain areas associated with motor control. That receptor inhibition is mediated by decreased receptor phosphorylation, suggesting an indirect modulation of cell signaling pathways to achieve

  7. Changes in apomorphine-induced stereotypy as a result of subacute neuroleptic treatment correlates with increased D-2 receptors, but not with increases in D-1 receptors.

    PubMed

    Fleminger, S; Rupniak, N M; Hall, M D; Jenner, P; Marsden, C D

    1983-10-01

    Administration of haloperidol (5 mg/kg i.p.), cis-flupenthixol (2.5 mg/kg i.p.) or sulpiride (2 X 100 mg/kg i.p.) daily for 21 days followed by a 3-day drug withdrawal period caused equivalent cerebral dopamine receptor supersensitivity as judged by enhanced apomorphine-induced stereotypy. These treatments also produced equivalent rises in the number of adenylate cyclase-independent dopamine receptors (D-2) in both striatal and mesolimbic tissue as assessed by specific [3H]spiperone and [3H]N,n-propylnorapomorphine (NPA) binding. No change in the dissociation constant (KD) was apparent in response to neuroleptic treatment. However, only repeated administration of cis-flupenthixol caused an increase in the number of adenylate cyclase-linked dopamine receptors (D-1) in striatum as assessed by enhanced [3H]piflutixol binding and increased dopamine-stimulated cyclic AMP formation. The dissociation constant for [3H]piflutixol binding was unchanged by cis-flupenthixol administration. No change in D-1 receptor numbers or dopamine stimulation of adenylate cyclase occurred in mesolimbic tissue. Repeated treatment with sulpiride or haloperidol was without effect on either [3H]piflutixol binding to D-1 receptors or cyclic AMP formation. In conclusion, increased apomorphine-induced stereotypy following subacute neuroleptic treatment correlates with changes in D-2 receptor numbers, but not with changes in D-1 receptors.

  8. Dopamine D₄ receptor counteracts morphine-induced changes in µ opioid receptor signaling in the striosomes of the rat caudate putamen.

    PubMed

    Suárez-Boomgaard, Diana; Gago, Belén; Valderrama-Carvajal, Alejandra; Roales-Buján, Ruth; Van Craenenbroeck, Kathleen; Duchou, Jolien; Borroto-Escuela, Dasiel O; Medina-Luque, José; de la Calle, Adelaida; Fuxe, Kjell; Rivera, Alicia

    2014-01-21

    The mu opioid receptor (MOR) is critical in mediating morphine analgesia. However, prolonged exposure to morphine induces adaptive changes in this receptor leading to the development of tolerance and addiction. In the present work we have studied whether the continuous administration of morphine induces changes in MOR protein levels, its pharmacological profile, and MOR-mediated G-protein activation in the striosomal compartment of the rat CPu, by using immunohistochemistry and receptor and DAMGO-stimulated [35S]GTPγS autoradiography. MOR immunoreactivity, agonist binding density and its coupling to G proteins are up-regulated in the striosomes by continuous morphine treatment in the absence of changes in enkephalin and dynorphin mRNA levels. In addition, co-treatment of morphine with the dopamine D4 receptor (D4R) agonist PD168,077 fully counteracts these adaptive changes in MOR, in spite of the fact that continuous PD168,077 treatment increases the [3H]DAMGO Bmax values to the same degree as seen after continuous morphine treatment. Thus, in spite of the fact that both receptors can be coupled to Gi/0 protein, the present results give support for the existence of antagonistic functional D4R-MOR receptor-receptor interactions in the adaptive changes occurring in MOR of striosomes on continuous administration of morphine.

  9. Mechanical stretch augments insulin-induced vascular smooth muscle cell proliferation by insulin-like growth factor-1 receptor

    SciTech Connect

    Liu, Gang; Hitomi, Hirofumi; Hosomi, Naohisa; Lei, Bai; Nakano, Daisuke; Deguchi, Kazushi; Mori, Hirohito; Masaki, Tsutomu; Ma, Hong; Griendling, Kathy K.; Nishiyama, Akira

    2011-10-15

    Insulin resistance and hypertension have been implicated in the pathogenesis of cardiovascular disease; however, little is known about the roles of insulin and mechanical force in vascular smooth muscle cell (VSMC) remodeling. We investigated the contribution of mechanical stretch to insulin-induced VSMC proliferation. Thymidine incorporation was stimulated by insulin in stretched VSMCs, but not in un-stretched VSMCs. Insulin increased 2-deoxy-glucose incorporation in both stretched and un-stretched VSMCs. Mechanical stretch augmented insulin-induced extracellular signal-regulated kinase (ERK) and Akt phosphorylation. Inhibitors of epidermal growth factor (EGF) receptor tyrosine kinase and Src attenuated insulin-induced ERK and Akt phosphorylation, as well as thymidine incorporation, whereas 2-deoxy-glucose incorporation was not affected by these inhibitors. Moreover, stretch augmented insulin-like growth factor (IGF)-1 receptor expression, although it did not alter the expression of insulin receptor and insulin receptor substrate-1. Insulin-induced ERK and Akt activation, and thymidine incorporation were inhibited by siRNA for the IGF-1 receptor. Mechanical stretch augments insulin-induced VSMC proliferation via upregulation of IGF-1 receptor, and downstream Src/EGF receptor-mediated ERK and Akt activation. Similar to in vitro experiment, IGF-1 receptor expression was also augmented in hypertensive rats. These results provide a basis for clarifying the molecular mechanisms of vascular remodeling in hypertensive patients with hyperinsulinemia. -- Highlights: {yields} Mechanical stretch augments insulin-induced VSMC proliferation via IGF-1 receptor. {yields} Src/EGFR-mediated ERK and Akt phosphorylation are augmented in stretched VSMCs. {yields} Similar to in vitro experiment, IGF-1 receptor is increased in hypertensive rats. {yields} Results provide possible mechanisms of vascular remodeling in hypertension with DM.

  10. In silico analysis of the histaprodifen induced activation pathway of the guinea-pig histamine H1-receptor

    NASA Astrophysics Data System (ADS)

    Straßer, Andrea; Wittmann, Hans-Joachim

    2010-09-01

    The binding of (partial) agonists in the binding pocket of biogenic amine receptors induces a conformational change from the inactive to the active state of the receptors. There is only little knowledge about the binding pathways of ligands into binding pocket on molecular level. So far, it was not possible with molecular dynamic simulations to observe the ligand binding and receptor activation. Furthermore, there is nearly nothing known, in which state of ligand binding, the receptor gets activated. The aim of this study was to get more detailed insight into the process of ligand binding and receptor activation. With the recently developed LigPath algorithm, we scanned the potential energy surface of the binding process of dimeric histaprodifen, a partial agonist at the histamine H1-receptor, into the guinea pig histamine H1-receptor, taking also into account the receptor activation. The calculations exhibited large conformational changes of Trp6.48 and Phe6.55 during ligand binding and receptor activation. Additionally, conformational changes were also observed for Phe6.52, Tyr6.51 and Phe6.44. Conformational changes of Trp6.48 and Phe6.52 are discussed in literature as rotamer toggle switch in context with receptor activation. Additionally, the calculations indicate that the binding of dimeric histaprodifen, accompanied by receptor activation is energetically preferred. In general, this study gives new, theoretical insights onto ligand binding and receptor activation on molecular level.

  11. Insulin-induced myosin light-chain phosphorylation during receptor capping in IM-9 human B-lymphoblasts.

    PubMed Central

    Majercik, M H; Bourguignon, L Y

    1988-01-01

    We have examined further the interaction between insulin surface receptors and the cytoskeleton of IM-9 human lymphoblasts. Using immunocytochemical techniques, we determined that actin, myosin, calmodulin and myosin light-chain kinase (MLCK) are all accumulated directly underneath insulin-receptor caps. In addition, we have now established that the concentration of intracellular Ca2+ (as measured by fura-2 fluorescence) increases just before insulin-induced receptor capping. Most importantly, we found that the binding of insulin to its receptor induces phosphorylation of myosin light chain in vivo. Furthermore, a number of drugs known to abolish the activation properties of calmodulin, such as trifluoperazine (TFP) or W-7, strongly inhibit insulin-receptor capping and myosin light-chain phosphorylation. These data imply that an actomyosin cytoskeletal contraction, regulated by Ca2+/calmodulin and MLCK, is involved in insulin-receptor capping. Biochemical analysis in vitro has revealed that IM-9 insulin receptors are physically associated with actin and myosin; and most interestingly, the binding of insulin-receptor/cytoskeletal complex significantly enhances the phosphorylation of the 20 kDa myosin light chain. This insulin-induced phosphorylation is inhibited by calmodulin antagonists (e.g. TFP and W-7), suggesting that the phosphorylation is catalysed by MLCK. Together, these results strongly suggest that MLCK-mediated myosin light-chain phosphorylation plays an important role in regulating the membrane-associated actomyosin contraction required for the collection of insulin receptors into caps. Images Fig. 2. Fig. 4. PMID:3048249

  12. Inhibition of Receptor Interacting Protein Kinases Attenuates Cardiomyocyte Hypertrophy Induced by Palmitic Acid.

    PubMed

    Zhao, Mingyue; Lu, Lihui; Lei, Song; Chai, Hua; Wu, Siyuan; Tang, Xiaoju; Bao, Qinxue; Chen, Li; Wu, Wenchao; Liu, Xiaojing

    2016-01-01

    Palmitic acid (PA) is known to cause cardiomyocyte dysfunction. Cardiac hypertrophy is one of the important pathological features of PA-induced lipotoxicity, but the mechanism by which PA induces cardiomyocyte hypertrophy is still unclear. Therefore, our study was to test whether necroptosis, a receptor interacting protein kinase 1 and 3 (RIPK1 and RIPK3-) dependent programmed necrosis, was involved in the PA-induced cardiomyocyte hypertrophy. We used the PA-treated primary neonatal rat cardiac myocytes (NCMs) or H9c2 cells to study lipotoxicity. Our results demonstrated that cardiomyocyte hypertrophy was induced by PA treatment, determined by upregulation of hypertrophic marker genes and cell surface area enlargement. Upon PA treatment, the expression of RIPK1 and RIPK3 was increased. Pretreatment with the RIPK1 inhibitor necrostatin-1 (Nec-1), the PA-induced cardiomyocyte hypertrophy, was attenuated. Knockdown of RIPK1 or RIPK3 by siRNA suppressed the PA-induced myocardial hypertrophy. Moreover, a crosstalk between necroptosis and endoplasmic reticulum (ER) stress was observed in PA-treated cardiomyocytes. Inhibition of RIPK1 with Nec-1, phosphorylation level of AKT (Ser473), and mTOR (Ser2481) was significantly reduced in PA-treated cardiomyocytes. In conclusion, RIPKs-dependent necroptosis might be crucial in PA-induced myocardial hypertrophy. Activation of mTOR may mediate the effect of necroptosis in cardiomyocyte hypertrophy induced by PA.

  13. Amygdala opioid receptors mediate the electroacupuncture-induced deterioration of sleep disruptions in epilepsy rats

    PubMed Central

    2013-01-01

    Background Clinical and experimental evidence demonstrates that sleep and epilepsy reciprocally affect each other. Previous studies indicated that epilepsy alters sleep homeostasis; in contrast, sleep disturbance deteriorates epilepsy. If a therapy possesses both epilepsy suppression and sleep improvement, it would be the priority choice for seizure control. Effects of acupuncture of Feng-Chi (GB20) acupoints on epilepsy suppression and insomnia treatment have been documented in the ancient Chinese literature, Lingshu Jing (Classic of the Miraculous Pivot). Therefore, this study was designed to investigate the effect of electroacupuncture (EA) stimulation of bilateral Feng-Chi acupoints on sleep disruptions in rats with focal epilepsy. Results Our result indicates that administration of pilocarpine into the left central nucleus of amygdala (CeA) induced focal epilepsy and decreased both rapid eye movement (REM) sleep and non-REM (NREM) sleep. High-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints, in which a 30-min EA stimulation was performed before the dark period of the light:dark cycle in three consecutive days, further deteriorated pilocarpine-induced sleep disruptions. The EA-induced exacerbation of sleep disruption was blocked by microinjection of naloxone, μ- (naloxonazine), κ- (nor-binaltorphimine) or δ-receptor antagonists (natrindole) into the CeA, suggesting the involvement of amygdaloid opioid receptors. Conclusion The present study suggests that high-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints exhibits no benefit in improving pilocarpine-induced sleep disruptions; in contrast, EA further deteriorated sleep disturbances. Opioid receptors in the CeA mediated EA-induced exacerbation of sleep disruptions in epileptic rats. PMID:24215575

  14. BMP type I receptor ALK2 is required for angiotensin II-induced cardiac hypertrophy.

    PubMed

    Shahid, Mohd; Spagnolli, Ester; Ernande, Laura; Thoonen, Robrecht; Kolodziej, Starsha A; Leyton, Patricio A; Cheng, Juan; Tainsh, Robert E T; Mayeur, Claire; Rhee, David K; Wu, Mei X; Scherrer-Crosbie, Marielle; Buys, Emmanuel S; Zapol, Warren M; Bloch, Kenneth D; Bloch, Donald B

    2016-04-15

    Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis.

  15. The Protective Role of PAC1-Receptor Agonist Maxadilan in BCCAO-Induced Retinal Degeneration.

    PubMed

    Vaczy, A; Reglodi, D; Somoskeoy, T; Kovacs, K; Lokos, E; Szabo, E; Tamas, A; Atlasz, T

    2016-10-01

    A number of studies have proven that pituitary adenylate cyclase activating polypeptide (PACAP) is protective in neurodegenerative diseases. Permanent bilateral common carotid artery occlusion (BCCAO) causes severe degeneration in the rat retina. In our previous studies, protective effects were observed with PACAP1-38, PACAP1-27, and VIP but not with their related peptides, glucagon, or secretin in BCCAO. All three PACAP receptors (PAC1, VPAC1, VPAC2) appear in the retina. Molecular and immunohistochemical analysis demonstrated that the retinoprotective effects are most probably mainly mediated by the PAC1 receptor. The aim of the present study was to investigate the retinoprotective effects of a selective PAC1-receptor agonist maxadilan in BCCAO-induced retinopathy. Wistar rats were used in the experiment. After performing BCCAO, the right eye was treated with intravitreal maxadilan (0.1 or 1 μM), while the left eye was injected with vehicle. Sham-operated rats received the same treatment. Two weeks after the operation, retinas were processed for standard morphometric and molecular analysis. Intravitreal injection of 0.1 or 1 μM maxadilan caused significant protection in the thickness of most retinal layers and the number of cells in the GCL compared to the BCCAO-operated eyes. In addition, 1 μM maxadilan application was more effective than 0.1 μM maxadilan treatment in the ONL, INL, IPL, and the entire retina (OLM-ILM). Maxadilan treatment significantly decreased cytokine expression (CINC-1, IL-1α, and L-selectin) in ischemia. In summary, our histological and molecular analysis showed that maxadilan, a selective PAC1 receptor agonist, has a protective role in BCCAO-induced retinal degeneration, further supporting the role of PAC1 receptor conveying the retinoprotective effects of PACAP.

  16. Toll-like receptor 2 modulates the proinflammatory milieu in Staphylococcus aureus-induced brain abscess.

    PubMed

    Kielian, Tammy; Haney, Anessa; Mayes, Patrick M; Garg, Sarita; Esen, Nilufer

    2005-11-01

    Toll-like receptor 2 (TLR2) is a pattern recognition receptor (PRR) that plays an important role in innate immune recognition of conserved structural motifs on a wide array of pathogens, including Staphylococcus aureus. To ascertain the functional significance of TLR2 in the context of central nervous system (CNS) parenchymal infection, we evaluated the pathogenesis of S. aureus-induced experimental brain abscess in TLR2 knockout (KO) and wild-type (WT) mice. The expression of several proinflammatory mediators, including inducible nitric oxide synthase, tumor necrosis factor alpha, and macrophage inflammatory protein-2, was significantly attenuated in brain abscesses of TLR2 KO mice compared to WT mice during the acute phase of infection. Conversely, interleukin-17 (IL-17), a cytokine produced by activated and memory T cells, was significantly elevated in lesions of TLR2 KO mice, suggesting an association between innate and adaptive immunity in brain abscess. Despite these differences, brain abscess severity in TLR2 KO and WT animals was similar, with comparable mortality rates, bacterial titers, and blood-brain barrier permeability, implying a role for alternative PRRs. Expression of the phagocytic PRRs macrophage scavenger receptor type AI/AII and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) was increased in brain abscesses of both TLR2 KO and WT mice compared to uninfected animals. However, LOX-1 induction in brain abscesses of TLR2 KO mice was significantly attenuated compared to WT animals, revealing that the TLR2-dependent signal(s) influence LOX-1 expression. Collectively, these findings reveal the complex nature of gram-positive bacterial recognition in the CNS which occurs, in part, through engagement of TLR2 and highlight the importance of receptor redundancy for S. aureus detection in the CNS.

  17. The gene pat-2, which induces natural parthenocarpy, alters the gibberellin content in unpollinated tomato ovaries.

    PubMed

    Fos, M; Nuez, F; García-Martínez, J L

    2000-02-01

    We investigated the role of gibberellins (GAs) in the effect of pat-2, a recessive mutation that induces facultative parthenocarpic fruit development in tomato (Lycopersicon esculentum Mill.) using near-isogenic lines with two different genetic backgrounds. Unpollinated wild-type Madrigal (MA/wt) and Cuarenteno (CU/wt) ovaries degenerated, but GA(3) application induced parthenocarpic fruit growth. On the contrary, parthenocarpic growth of MA/pat-2 and CU/pat-2 fruits, which occurs in the absence of pollination and hormone application, was not affected by GA(3). Pollinated MA/wt and parthenocarpic MA/pat-2 ovary development was negated by paclobutrazol, and this inhibitory effect was counteracted by GA(3). The main GAs of the early-13-hydroxylation pathway (GA(1), GA(3), GA(8), GA(19), GA(20), GA(29), GA(44), GA(53), and, tentatively, GA(81)) and two GAs of the non-13-hydroxylation pathway (GA(9) and GA(34)) were identified in MA/wt ovaries by gas chromatography-selected ion monitoring. GAs were quantified in unpollinated ovaries at flower bud, pre-anthesis, and anthesis. In unpollinated MA/pat-2 and CU/pat-2 ovaries, the GA(20) content was much higher (up to 160 times higher) and the GA(19) content was lower than in the corresponding non-parthenocarpic ovaries. The application of an inhibitor of 2-oxoglutarate-dependent dioxygenases suggested that GA(20) is not active per se. The pat-2 mutation may increase GA 20-oxidase activity in unpollinated ovaries, leading to a higher synthesis of GA(20), the precursor of an active GA.

  18. Implication of Prostaglandins and Histamine H1 and H2 Receptors in Radiation-Induced Temperature Responses of Rats

    DTIC Science & Technology

    1988-05-01

    1988) S Implication of Prostaglandins and Histamine H1 and H 2 Receptors in Radiation-Induced Temperature Responses of Rats SATHASIVA B. KANDASAMY ... KANDASAMY , S. B., HUNT. W. A., AND MICKLEY, G. A. Implications of Prostaglandins and Histamine H I and H2 Receptors in Radiation-Induced Temperature...lateral ventricle according to coordinates derived from the atlas of Pelligrino et al. (31): 0.8 mm posterior to bregma. 2.5 mm lateral. 44 KANDASAMY , HUNT

  19. Progesterone-induced activation of membrane-bound progesterone receptors in murine macrophage cells.

    PubMed

    Lu, Jing; Reese, Joshua; Zhou, Ying; Hirsch, Emmet

    2015-02-01

    Parturition is an inflammatory process mediated to a significant extent by macrophages. Progesterone (P4) maintains uterine quiescence in pregnancy, and a proposed functional withdrawal of P4 classically regulated by nuclear progesterone receptors (nPRs) leads to labor. P4 can affect the functions of macrophages despite the reported lack of expression of nPRs in these immune cells. Therefore, in this study we investigated the effects of the activation of the putative membrane-associated PR on the function of macrophages (a key cell for parturition) and discuss the implications of these findings for pregnancy and parturition. In murine macrophage cells (RAW 264.7), activation of mPRs by P4 modified to be active only extracellularly by conjugation to BSA (P4BSA, 1.0×10(-7) mol/l) caused a pro-inflammatory shift in the mRNA expression profile, with significant upregulation of the expression of cyclooxygenase 2 (COX2 (Ptgs2)), Il1B, and Tnf and downregulation of membrane progesterone receptor alpha (Paqr7) and oxytocin receptor (Oxtr). Pretreatment with PD98059, a MEK1/2 inhibitor, significantly reduced P4BSA-induced expression of mRNA of Il1B, Tnf, and Ptgs2. Inhibition of protein kinase A (PKA) by H89 blocked P4BSA-induced expression of Il1B and Tnf mRNA. P4BSA induced rapid phosphorylation of MEK1/2 and CREB (a downstream target of PKA). This phosphorylation was inhibited by pretreatment with PD98059 and H89, respectively, revealing that MEK1/2 and PKA are two of the components involved in mPR signaling. Taken together, these results indicate that changes in membrane progesterone receptor alpha expression and signaling in macrophages are associated with the inflammatory responses; and that these changes might contribute to the functional withdrawal of P4 related to labor.

  20. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila.

    PubMed

    Cassar, Marlène; Issa, Abdul-Raouf; Riemensperger, Thomas; Petitgas, Céline; Rival, Thomas; Coulom, Hélène; Iché-Torres, Magali; Han, Kyung-An; Birman, Serge

    2015-01-01

    Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca(2+), also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans.

  1. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila

    PubMed Central

    Cassar, Marlène; Issa, Abdul-Raouf; Riemensperger, Thomas; Petitgas, Céline; Rival, Thomas; Coulom, Hélène; Iché-Torres, Magali; Han, Kyung-An; Birman, Serge

    2015-01-01

    Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca2+, also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans. PMID:25158689

  2. Inhibition of N-methyl-D-aspartate receptors increases paraoxon-induced apoptosis in cultured neurons

    SciTech Connect

    Wu Xuan; Tian Feng; Okagaki, Peter; Marini, Ann M. . E-mail: amarini@usuhs.mil

    2005-10-01

    Organophosphorus (OP) compounds, used as insecticides and chemical warfare agents, are potent neurotoxins. We examined the neurotoxic effect of paraoxon (O,O-diethyl O-p-nitrophenyl phosphate), an organophosphate compound, and the role of NMDA receptors as a mechanism of action in cultured cerebellar granule cells. Paraoxon is neurotoxic to cultured rat cerebellar granule cells in a time- and concentration-dependent manner. Cerebellar granule cells are less sensitive to the neurotoxic effects of paraoxon on day in vitro (DIV) 4 than neurons treated on DIV 8. Surprisingly, the N-methyl-D-aspartate (NMDA) receptor antagonist, MK-801, enhances paraoxon-mediated neurotoxicity suggesting that NMDA receptors may play a protective role. Pretreatment with a subtoxic concentration of N-methyl-D-aspartate (NMDA) [100 {mu}M] protects about 40% of the vulnerable neurons that would otherwise die from paraoxon-induced neurotoxicity. Moreover, addition of a neuroprotective concentration of NMDA 3 h after treatment with paraoxon provides the same level of protection. Because paraoxon-mediated neuronal cell death is time-dependent, we hypothesized that apoptosis may be involved. Paraoxon increases apoptosis about 10-fold compared to basal levels. The broad-spectrum caspase inhibitor (Boc-D-FMK) and the caspase-9-specific inhibitor (Z-LEHD-FMK) protect against paraoxon-mediated apoptosis, paraoxon-stimulated caspase-3 activity and neuronal cell death. MK-801 increases, whereas NMDA blocks paraoxon-induced apoptosis and paraoxon-stimulated caspase-3 activity. These results suggest that activation of NMDA receptors protect neurons against paraoxon-induced neurotoxicity by blocking apoptosis initiated by paraoxon.

  3. hvTRA, a novel TRAIL receptor agonist, induces apoptosis and sustained growth retardation in melanoma.

    PubMed

    Fleten, Karianne G; Flørenes, Vivi Ann; Prasmickaite, Lina; Hill, Oliver; Sykora, Jaromir; Mælandsmo, Gunhild M; Engesæter, Birgit

    2016-01-01

    In recent years, new treatment options for malignant melanoma patients have enhanced the overall survival for selected patients. Despite new hope, most melanoma patients still relapse with drug-resistant tumors or experience intrinsic resistance to the therapy. Therefore, novel treatment modalities beneficial for subgroups of patients are needed. TRAIL receptor agonists have been suggested as promising candidates for use in cancer treatment as they preferentially induce apoptosis in cancer cells. Unfortunately, the first generation of TRAIL receptor agonists showed poor clinical efficacy. hvTRA is a second-generation TRAIL receptor agonist with improved composition giving increased potency, and in the present study, we showed hvTRA-induced activation of apoptosis leading to an efficient and sustained reduction in melanoma cell growth in cell lines and xenograft models. Furthermore, the potential of hvTRA in a clinical setting was demonstrated by showing efficacy on tumor cells harvested from melanoma patients with lymph node metastasis in an ex vivo drug sensitivity assay. Inhibition of mutated BRAF has been shown to regulate proteins in the intrinsic apoptotic pathway, making the cells more susceptible for apoptosis induction. In an attempt to increase the efficacy of hvTRA, combination treatment with the mutated BRAF inhibitor vemurafenib was investigated. A synergistic effect by the combination was observed for several cell lines in vitro, and an initial cytotoxic effect was observed in vivo. Unfortunately, the initial increased reduction in tumor growth compared with hvTRA mono treatment was not sustained, and this was related to downregulation of the DR5 level by vemurafenib. Altogether, the presented data imply that hvTRA efficiently induce apoptosis and growth delay in melanoma models and patient material, and the potential of this TRAIL receptor agonist should be further evaluated for treatment of subgroups of melanoma patients.

  4. hvTRA, a novel TRAIL receptor agonist, induces apoptosis and sustained growth retardation in melanoma

    PubMed Central

    Fleten, Karianne G; Flørenes, Vivi Ann; Prasmickaite, Lina; Hill, Oliver; Sykora, Jaromir; Mælandsmo, Gunhild M; Engesæter, Birgit

    2016-01-01

    In recent years, new treatment options for malignant melanoma patients have enhanced the overall survival for selected patients. Despite new hope, most melanoma patients still relapse with drug-resistant tumors or experience intrinsic resistance to the therapy. Therefore, novel treatment modalities beneficial for subgroups of patients are needed. TRAIL receptor agonists have been suggested as promising candidates for use in cancer treatment as they preferentially induce apoptosis in cancer cells. Unfortunately, the first generation of TRAIL receptor agonists showed poor clinical efficacy. hvTRA is a second-generation TRAIL receptor agonist with improved composition giving increased potency, and in the present study, we showed hvTRA-induced activation of apoptosis leading to an efficient and sustained reduction in melanoma cell growth in cell lines and xenograft models. Furthermore, the potential of hvTRA in a clinical setting was demonstrated by showing efficacy on tumor cells harvested from melanoma patients with lymph node metastasis in an ex vivo drug sensitivity assay. Inhibition of mutated BRAF has been shown to regulate proteins in the intrinsic apoptotic pathway, making the cells more susceptible for apoptosis induction. In an attempt to increase the efficacy of hvTRA, combination treatment with the mutated BRAF inhibitor vemurafenib was investigated. A synergistic effect by the combination was observed for several cell lines in vitro, and an initial cytotoxic effect was observed in vivo. Unfortunately, the initial increased reduction in tumor growth compared with hvTRA mono treatment was not sustained, and this was related to downregulation of the DR5 level by vemurafenib. Altogether, the presented data imply that hvTRA efficiently induce apoptosis and growth delay in melanoma models and patient material, and the potential of this TRAIL receptor agonist should be further evaluated for treatment of subgroups of melanoma patients. PMID:28028438

  5. Bone Cell-autonomous Contribution of Type 2 Cannabinoid Receptor to Breast Cancer-induced Osteolysis.

    PubMed

    Sophocleous, Antonia; Marino, Silvia; Logan, John G; Mollat, Patrick; Ralston, Stuart H; Idris, Aymen I

    2015-09-04

    The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumor growth, bone remodeling, and bone pain. However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here we found that the CB2-selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micromolar concentrations. Under conditions in which these ligands are used at the nanomolar range, HU308 and JWH133 enhanced human and mouse breast cancer cell-induced osteoclastogenesis and exacerbated osteolysis, and these effects were attenuated in cultures obtained from CB2-deficient mice or in the presence of a CB2 receptor blocker. HU308 and JWH133 had no effects on osteoblast growth or differentiation in the presence of conditioned medium from breast cancer cells, but under these circumstances both agents enhanced parathyroid hormone-induced osteoblast differentiation and the ability to support osteoclast formation. Mechanistic studies in osteoclast precursors and osteoblasts showed that JWH133 and HU308 induced PI3K/AKT activity in a CB2-dependent manner, and these effects were enhanced in the presence of osteolytic and osteoblastic factors such as RANKL (receptor activator of NFκB ligand) and parathyroid hormone. When combined with published work, these findings suggest that breast cancer and bone cells exhibit differential responses to treatment with CB2 ligands depending upon cell type and concentration used. We, therefore, conclude that both CB2-selective activation and antagonism have potential efficacy in cancer-associated bone disease, but further studies are warranted and ongoing.

  6. Bone Cell-autonomous Contribution of Type 2 Cannabinoid Receptor to Breast Cancer-induced Osteolysis*

    PubMed Central

    Sophocleous, Antonia; Marino, Silvia; Logan, John G.; Mollat, Patrick; Ralston, Stuart H.; Idris, Aymen I.

    2015-01-01

    The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumor growth, bone remodeling, and bone pain. However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here we found that the CB2-selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micromolar concentrations. Under conditions in which these ligands are used at the nanomolar range, HU308 and JWH133 enhanced human and mouse breast cancer cell-induced osteoclastogenesis and exacerbated osteolysis, and these effects were attenuated in cultures obtained from CB2-deficient mice or in the presence of a CB2 receptor blocker. HU308 and JWH133 had no effects on osteoblast growth or differentiation in the presence of conditioned medium from breast cancer cells, but under these circumstances both agents enhanced parathyroid hormone-induced osteoblast differentiation and the ability to support osteoclast formation. Mechanistic studies in osteoclast precursors and osteoblasts showed that JWH133 and HU308 induced PI3K/AKT activity in a CB2-dependent manner, and these effects were enhanced in the presence of osteolytic and osteoblastic factors such as RANKL (receptor activator of NFκB ligand) and parathyroid hormone. When combined with published work, these findings suggest that breast cancer and bone cells exhibit differential responses to treatment with CB2 ligands depending upon cell type and concentration used. We, therefore, conclude that both CB2-selective activation and antagonism have potential efficacy in cancer-associated bone disease, but further studies are warranted and ongoing. PMID:26195631

  7. Activation of PPAR gamma receptors reduces levodopa-induced dyskinesias in 6-OHDA-lesioned rats.

    PubMed

    Martinez, A A; Morgese, M G; Pisanu, A; Macheda, T; Paquette, M A; Seillier, A; Cassano, T; Carta, A R; Giuffrida, A

    2015-02-01

    Long-term administration of l-3,4-dihydroxyphenylalanine (levodopa), the mainstay treatment for Parkinson's disease (PD), is accompanied by fluctuations in its duration of action and motor complications (dyskinesia) that dramatically affect the quality of life of patients. Levodopa-induced dyskinesias (LID) can be modeled in rats with unilateral 6-OHDA lesions via chronic administration of levodopa, which causes increasingly severe axial, limb, and orofacial abnormal involuntary movements (AIMs) over time. In previous studies, we showed that the direct activation of CB1 cannabinoid receptors alleviated rat AIMs. Interestingly, elevation of the endocannabinoid anandamide by URB597 (URB), an inhibitor of endocannabinoid catabolism, produced an anti-dyskinetic response that was only partially mediated via CB1 receptors and required the concomitant blockade of transient receptor potential vanilloid type-1 (TRPV1) channels by capsazepine (CPZ) (Morgese et al., 2007). In this study, we showed that the stimulation of peroxisome proliferator-activated receptors (PPAR), a family of transcription factors activated by anandamide, contributes to the anti-dyskinetic effects of URB+CPZ, and that the direct activation of the PPARγ subtype by rosiglitazone (RGZ) alleviates levodopa-induced AIMs in 6-OHDA rats. AIM reduction was associated with an attenuation of levodopa-induced increase of dynorphin, zif-268, and of ERK phosphorylation in the denervated striatum. RGZ treatment did not decrease striatal levodopa and dopamine bioavailability, nor did it affect levodopa anti-parkinsonian activity. Collectively, these data indicate that PPARγ may represent a new pharmacological target for the treatment of LID.

  8. Kinin-B2 Receptor Exerted Neuroprotection After Diisopropylfluorophosphate-induced Neuronal Damage

    PubMed Central

    Torres-Rivera, Wilmarie; Pérez, Dinely; Park, Keon-Young; Carrasco, Marimée; Platt, Manu O.; Eterović, Vesna A.; Ferchmin, Pedro A.; Ulrich, Henning; Martins, Antonio H.

    2013-01-01

    The kinin-B2 receptor (B2BKR) activated by its endogenous ligand bradykinin participates in various metabolic processes including control of arterial pressure and inflammation. Recently, functions for this receptor in brain development and protection against glutamate-provoked excitotoxicity have been proposed. Here, we report neuroprotective properties for bradykinin against organophosphate poisoning using acute hippocampal slices as an in vitro model. Following slice perfusion for 10 min with diisopropylfluorophosphate (DFP) to initiate the noxious stimulus, responses of pyramidal neurons upon an electric impulse were reduced to less than 30 % of control amplitudes. Effects on synaptic-elicited population spikes were reverted when preparations had been exposed to bradykinin 30 min after challenging with DFP. Accordingly, bradykinin-induced population spike recovery was abolished by HOE-140, a B2BKR antagonist. However, the kinin-B1 receptor (B1BKR) agonist Lys-des-Arg9-bradykinin, inducing phosphorylation of MEK/MAPK and cell death, abolished bradykinin-mediated neuroprotection, an effect, which was reverted by the ERK inhibitor PD98059. In agreement with pivotal B1BKR functions in this process, antagonism of endogenous B1BKR activity alone was enough for restoring population spike activity. On the other hand pralidoxime, an oxime, reactivating AChE after organophosphate poisoning, induced population spike recovery after DFP exposure in the presence of bradykinin and Lys-des-Arg9-bradykinin. Lys-des-Arg9-bradykinin did not revert protection exerted by pralidoxime, however when instead bradykinin and Ly-des-Arg9-bradykinin were superfused together, recovery of population spikes diminished. These findings again confirm the neuroprotective feature of bradykinin, which is, diminished by its endogenous metabolites, stimulating the B1BKR, providing a novel understanding of physiological roles of these receptors. PMID:23735753

  9. Interaction of anesthesia, beta-receptor blockade, and blood loss in dogs with induced myocardial infarction.

    PubMed

    Prys-Roberts, C; Roberts, J G; Foëx, P; Clarke, T N; Bennett, M J; Ryder, W A

    1976-09-01

    The cardiovascular effects of halothane-nitrous oxide anesthesia, and beta-receptor blockade with either propranolol or practolol, were studied in 15 dogs in which severe myocardial infarction had been induced ten days earlier. The hemodynamic responses to blood loss amounting to 25 per cent of estimated blood volume, and its subsequent replacement, were studied before and after induction of beta-receptor blockade. In terms of cardiac output and aortic blood flow acceleration, cardiac performance in the absence of beta-blockade was markedly impaired during steady-state anesthesia, compared with corresponding values in normal dogs. Practolol (2.0 mg/kg) administered during anesthesia induced no significant circulatory change other than a 14 per cent decrease in heart rate and a 25 per cent increase in strode volum. Propranolol (0.3 mg/kg) caused a comparable reduction of heart rate, but significantly reduced cardiac output (-27 per cent), aortic blood flow acceleration (-26 per cent), and peak LV power (-19 per cent), and increased systemic vascular resistance (+49 per cent). The two drugs caused comparable shifts of the isoproterenol dose-response curve during anesthesia. Graduated blood loss during anesthesia, to a total of 25 per cent of blood volume, caused consistent circulatory changes (decreased mean arterial pressure cardiac output, peak LV power, LV minute work) that were essentially similar before and after beta-receptor blockade with either propranolol or practolol. The positive inotropic effect of calcium gluconate during halothane anesthesia was significantly reduced following either propranolol or practolol, but the hemodynamic responses to changes of systemic vascular resistance induced with acetylcholine or phenylephrine were not modified by beta-receptor blockade.

  10. Contribution of renal purinergic receptors to renal vasoconstriction in angiotensin II-induced hypertensive rats.

    PubMed

    Franco, Martha; Bautista, Rocio; Tapia, Edilia; Soto, Virgilia; Santamaría, José; Osorio, Horacio; Pacheco, Ursino; Sánchez-Lozada, L Gabriela; Kobori, Hiroyuki; Navar, L Gabriel

    2011-06-01

    To investigate the participation of purinergic P2 receptors in the regulation of renal function in ANG II-dependent hypertension, renal and glomerular hemodynamics were evaluated in chronic ANG II-infused (14 days) and Sham rats during acute blockade of P2 receptors with PPADS. In addition, P2X1 and P2Y1 protein and mRNA expression were compared in ANG II-infused and Sham rats. Chronic ANG II-infused rats exhibited increased afferent and efferent arteriolar resistances and reductions in glomerular blood flow, glomerular filtration rate (GFR), single-nephron GFR (SNGFR), and glomerular ultrafiltration coefficient. PPADS restored afferent and efferent resistances as well as glomerular blood flow and SNGFR, but did not ameliorate the elevated arterial blood pressure. In Sham rats, PPADS increased afferent and efferent arteriolar resistances and reduced GFR and SNGFR. Since purinergic blockade may influence nitric oxide (NO) release, we evaluated the role of NO in the response to PPADS. Acute blockade with N(ω)-nitro-l-arginine methyl ester (l-NAME) reversed the vasodilatory effects of PPADS and reduced urinary nitrate excretion (NO(2)(-)/NO(3)(-)) in ANG II-infused rats, indicating a NO-mediated vasodilation during PPADS treatment. In Sham rats, PPADS induced renal vasoconstriction which was not modified by l-NAME, suggesting blockade of a P2X receptor subtype linked to the NO pathway; the response was similar to that obtained with l-NAME alone. P2X1 receptor expression in the renal cortex was increased by chronic ANG II infusion, but there were no changes in P2Y1 receptor abundance. These findings indicate that there is an enhanced P2 receptor-mediated vasoconstriction of afferent and efferent arterioles in chronic ANG II-infused rats, which contributes to the increased renal vascular resistance observed in ANG II-dependent hypertension.

  11. Light induced fluorescence for predicting API content in tablets: sampling and error.

    PubMed

    Domike, Reuben; Ngai, Samuel; Cooney, Charles L

    2010-05-31

    The use of a light induced fluorescence (LIF) instrument to estimate the total content of fluorescent active pharmaceutical ingredient in a tablet from surface sampling was demonstrated. Different LIF sampling strategies were compared to a total tablet ultraviolet (UV) absorbance test for each tablet. Testing was completed on tablets with triamterene as the active ingredient and on tablets with caffeine as the active ingredient, each with a range of concentrations. The LIF instrument accurately estimated the active ingredient within 10% of total tablet test greater than 95% of the time. The largest error amongst all of the tablets tested was 13%. The RMSEP between the techniques was in the range of 4.4-7.9%. Theory of the error associated with the surface sampling was developed and found to accurately predict the experimental error. This theory uses one empirically determined parameter: the deviation of estimations at different locations on the tablet surface. As this empirical parameter can be found rapidly, correct use of this prediction of error may reduce the effort required for calibration and validation studies of non-destructive surface measurement techniques, and thereby rapidly determine appropriate analytical techniques for estimating content uniformity in tablets.

  12. Magnetism and thermal induced characteristics of Fe2O3 content bioceramics

    NASA Astrophysics Data System (ADS)

    Wu, Chun-Shiang; Hsi, Chi-Shiung; Hsu, Fang-Chi; Wang, Moo-Chin; Chen, Yung-Sheng

    2012-11-01

    Magnetic properties of Li2O-MnO2-CaO-P2O5-SiO2 (LMCPS) glasses doped with various amounts of Fe2O3 were investigated. There is a dramatic change in the magnetic property of pristine LMCPS after the addition of Fe2O3 and crystallized at 850 °C for 4 h. Both the electron paramagnetic resonance and magnetic susceptibility measurements showed that the glass ceramic with 4 at% Fe2O3 exhibited the coexistence of superparamagnetism and ferromagnetism at room temperature. When the Fe2O3 content was higher than 8 at%, the LMCPS glasses showed ferromagnetism behavior. The complex magnetic behavior is due to the distribution of (Li, Mn)ferrite particle sizes driven by the Fe2O3 content. The thermal induced hysteresis loss of the crystallized LMCPS glass ceramics was characterized under an alternating magnetic field. The energy dissipations of the crystallized LMCPS glass ceramics were determined by the concentration and Mn/Fe ratios of Li(Mn, Fe)ferrite phase formed in the glass ceramics.

  13. Laser-induced fluorescence: quantitative analysis of atherosclerotic plaque chemical content in human aorta

    NASA Astrophysics Data System (ADS)

    Dai, Erbin; Wishart, David; Khoury, Samir; Kay, Cyril M.; Jugdutt, Bodh I.; Tulip, John; Lucas, Alexandra

    1996-05-01

    We have been studying laser-induced fluorescence as a technique for identification of selected changes in the chemical composition of atherosclerotic plaque. Formulae for quantification of chemical changes have been developed based upon analysis of fluorescence emission spectra using multiple regression analysis and the principal of least squares. The intima of human aortic necropsy specimens was injected with chemical compounds present in atherosclerotic plaque. Spectra recorded after injection of selected chemical components found in plaque (collagen I, III, IV, elastin and cholesterol) at varying concentrations (0.01 - 1.0 mg) were compared with saline injection. A single fiber system was used for both fluorescence excitation (XeCl excimer laser, 308 nm, 1.5 - 2.0 mJ/ pulse, 5 Hz) and fluorescence emission detection. Average spectra for each chemical have been developed and the wavelengths of peak emission intensity identified. Curve fitting analysis as well as multiple regression analysis were used to develop formulae for assessment of chemical content. Distinctive identifying average curves were established for each chemical. Excellent correlations were identified for collagen I, III, and IV, elastin, and cholesterol (R2 equals 0.92 6- 0.997). Conclusions: (1) Fluorescence spectra of human aortas were significantly altered by collagen I, collagen III, elastin and cholesterol. (2) Fluorescence spectroscopic analysis may allow quantitative assessment of atherosclerotic plaque chemical content in situ.

  14. Oleic acid content is responsible for the reduction in blood pressure induced by olive oil.

    PubMed

    Terés, S; Barceló-Coblijn, G; Benet, M; Alvarez, R; Bressani, R; Halver, J E; Escribá, P V

    2008-09-16

    Numerous studies have shown that high olive oil intake reduces blood pressure (BP). These positive effects of olive oil have frequently been ascribed to its minor components, such as alpha-tocopherol, polyphenols, and other phenolic compounds that are not present in other oils. However, in this study we demonstrate that the hypotensive effect of olive oil is caused by its high oleic acid (OA) content (approximately 70-80%). We propose that olive oil intake increases OA levels in membranes, which regulates membrane lipid structure (H(II) phase propensity) in such a way as to control G protein-mediated signaling, causing a reduction in BP. This effect is in part caused by its regulatory action on G protein-associated cascades that regulate adenylyl cyclase and phospholipase C. In turn, the OA analogues, elaidic and stearic acids, had no hypotensive activity, indicating that the molecular mechanisms that link membrane lipid structure and BP regulation are very specific. Similarly, soybean oil (with low OA content) did not reduce BP. This study demonstrates that olive oil induces its hypotensive effects through the action of OA.

  15. Perifosine induced release of contents of trans cell-barrier transport efficient liposomes.

    PubMed

    Koklic, Tilen

    2014-10-01

    Perifosine (OPP) containing liposomal formulation was previously found to deliver almost half of liposome encapsulated content through a tight cellular barrier in vitro. In order to understand the role of different liposome components, especially perifosine, in transendothelial transport the physical characteristics of liposome membranes composed of phosphatidylcholine, and cholesterol, as a main lipid constituents, and variable amount of helper lipids: dioleoyl phosphatidylethanolamine (DOPE), and alkylphospholipid perifosine. For this purpose, electron paramagnetic resonance (EPR) with computer aided EPR spectra simulation and fluorescence polarization spectroscopy were used to investigate how different membrane components influence membrane characteristics and the release of liposome entrapped substances. Beside methylester of palmitic acid with nitroxide group at different position on acyl chain usually used for such studies, the spin labeled and fluorescent labeled analog of perifosine were introduced. OPP increases membrane fluidity of liposomes as well as the release of liposome encapsulated content. The release of neutral molecules increases with OPP concentration, while the release of charged molecules is about an order of magnitude slower. Optimal OPP concentration, for release of charged molecules, is about 15 mol%. These results are one step further toward the conclusion that the lysolipid-containing liposomes could be promising trans endothelial delivery system, since lysolipids, such as OPP, open tight cellular barriers, as was published before, and in the same time induce the release of liposome encapsulated content at physiological temperature, as shown here. Since many drug delivery systems are being developed, which mainly exploit the transcellular route of delivery through barrier-forming cells, we hope that the uniqueness of lysolipid-containing liposomes, exploiting the paracellular route, and thus avoiding efflux transporters, will foster

  16. Effects of induced subacute ruminal acidosis on milk fat content and milk fatty acid profile.

    PubMed

    Enjalbert, F; Videau, Y; Nicot, M C; Troegeler-Meynadier, A

    2008-06-01

    Two lactating dairy cows fitted with a rumen cannula received successively diets containing 0%, 20%, 34% and again 0% of wheat on a dry matter basis. After 5, 10 and 11 days, ruminal pH was measured between 8:00 and 16:00 hours, and milk was analysed for fat content and fatty acid profile. Diets with 20% and 34% wheat induced a marginal and a severe subacute ruminal acidosis respectively. After 11 days, diets with wheat strongly reduced the milk yield and milk fat content, increased the proportions of C8:0 to C13:0 even- or odd-chain fatty acids, C18:2 n-6 and C18:3 n-3 fatty acids but decreased the proportions of C18:0 and cis-9 C18:1 fatty acids. Wheat also increased the proportions of trans-5 to trans-10 C18:1, the latter exhibiting a 10-fold increase with 34% of wheat compared with value during the initial 0% wheat period. There was also an increase of trans-10, cis-12 C18:2 fatty acid and a decrease of trans-11 to trans-16 C18:1 fatty acids. The evolution during adaptation or after return to a 0% wheat diet was rapid for pH but much slower for the fatty acid profile. The mean ruminal pH was closely related to milk fat content, the proportion of odd-chain fatty acids (linear relationship) and the ratio of trans-10 C18:1/trans-11 C18:1 (nonlinear relationship). Such changes in fatty acid profile suggested a possible use for non-invasive diagnosis of subacute ruminal acidosis.

  17. IL-1 receptor antagonist attenuates neonatal lipopolysaccharide-induced long-lasting learning impairment and hippocampal injury in adult rats

    PubMed Central

    Pang, Yi; Bhatt, Abhay J.; Fan, Lir-Wan

    2015-01-01

    We have previously reported that neonatal lipopolysaccharide (LPS) exposure resulted in an increase in interleukin-1β (IL-1β) content, injury to the hippocampus, and cognitive deficits in juvenile male and female rats, as well as female adult rats. The present study aimed to determine whether an antiinflammatory cytokine, interleukin-1 receptor antagonist (IL-1ra), protects against the neonatal LPS exposure-induced inflammatory responses, hippocampal injury, and long-lasting learning deficits in adult rats. LPS (1 mg/kg) or LPS plus IL-1ra (0.1 mg/kg) was injected intracerebrally to Sprague-Dawley male rat pups at postnatal day 5 (P5). Neurobehavioral tests were carried out on P21, P49, and P70, while neuropathological studies were conducted on P71. Our results showed that neonatal LPS exposure resulted in learning deficits in rats at both developmental and adult ages, as demonstrated by a significantly impaired performance in the passive avoidance task (P21, P49, and P70), reduced hippocampal volume, and reduced number of Nissl+ cells in the CA1 region of the middle dorsal hippocampus of P71 rat brain. Those neuropathological and neurobehavioral alterations by LPS exposure were associated with a sustained inflammatory response in the P71 rat hippocampus, indicated by increased number of activated microglia as well as elevated levels of IL-1β. Neonatal administration of IL-1ra significantly attenuated LPS-induced long-lasting learning deficits, hippocampal injury, and sustained inflammatory responses in P71 rats. Our study demonstrates that neonatal LPS exposure leads to a persistent injury to the hippocampus, resulting in long-lasting learning disabilities related to chronic inflammation in rats, and these effects can be attenuated with an IL-1 receptor antagonist. PMID:25665855

  18. IL-1 receptor antagonist attenuates neonatal lipopolysaccharide-induced long-lasting learning impairment and hippocampal injury in adult rats.

    PubMed

    Lan, Kuo-Mao; Tien, Lu-Tai; Pang, Yi; Bhatt, Abhay J; Fan, Lir-Wan

    2015-04-02

    We have previously reported that neonatal lipopolysaccharide (LPS) exposure resulted in an increase in interleukin-1β (IL-1β) content, injury to the hippocampus, and cognitive deficits in juvenile male and female rats, as well as female adult rats. The present study aimed to determine whether an anti-inflammatory cytokine, interleukin-1 receptor antagonist (IL-1ra), protects against the neonatal LPS exposure-induced inflammatory responses, hippocampal injury, and long-lasting learning deficits in adult rats. LPS (1 mg/kg) or LPS plus IL-1ra (0.1 mg/kg) was injected intracerebrally to Sprague-Dawley male rat pups at postnatal day 5 (P5). Neurobehavioral tests were carried out on P21, P49, and P70, while neuropathological studies were conducted on P71. Our results showed that neonatal LPS exposure resulted in learning deficits in rats at both developmental and adult ages, as demonstrated by a significantly impaired performance in the passive avoidance task (P21, P49, and P70), reduced hippocampal volume, and reduced number of Nissl+ cells in the CA1 region of the middle dorsal hippocampus of P71 rat brain. Those neuropathological and neurobehavioral alterations by LPS exposure were associated with a sustained inflammatory response in the P71 rat hippocampus, indicated by increased number of activated microglia as well as elevated levels of IL-1β. Neonatal administration of IL-1ra significantly attenuated LPS-induced long-lasting learning deficits, hippocampal injury, and sustained inflammatory responses in P71 rats. Our study demonstrates that neonatal LPS exposure leads to a persistent injury to the hippocampus, resulting in long-lasting learning disabilities related to chronic inflammation in rats, and these effects can be attenuated with an IL-1 receptor antagonist.

  19. Leukotriene receptor antagonists, LY293111 and ONO-1078, protect neurons from the sPLA2-IB-induced neuronal cell death independently of blocking their receptors.

    PubMed

    Yagami, Tatsurou; Yamamoto, Yasuhiro; Kohma, Hiromi

    2013-09-01

    In the ischemic brain, leukotrienes (LTs) are increased and their receptor antagonists protect neurons. However, it has not yet been sufficiently clarified how antagonists for LT receptors exhibit neuroprotective effects. In the present study, we evaluated protective effects of receptor antagonists for LTB4 (LY293111) and cysteinyl LTs (ONO-1078) in the primary culture of rat cortical neurons. The group IB secretory phospholipase A2 (sPLA2-IB)-induced neuronal cell death had been established as the in vitro model for cerebral ischemia. sPLA2-IB triggered the influx of Ca(2+) into neurons via L-type voltage-dependent calcium channel (L-VDCC). Subsequently, the enzyme produced eicosanoids including LTB4 before neuronal cell death. Neither administration of LTB4 nor cysteinyl LTs such as LTC4, LTD4 and LTE4 killed neurons. However, both LY293111 and ONO-1078 significantly prevented neurons from the neurotoxicity of sPLA2-IB, suggesting that the two LT receptor blockers protected neurons through alternative pathways beside LT receptors. An L-VDCC blocker does not only inhibit the influx of Ca(2+) into neurons but also rescues neurons from the sPLA2-IB-induced neuronal cell death. The two LT receptor antagonists also blocked the sPLA2-IB-induced Ca(2+) influx significantly. Thus, LTs exhibited no neurotoxicity, but their receptor antagonists protected neurons directly in the in vitro ischemic model. Furthermore, the suppression of L-VDCC appeared to be involved in the neuroprotective effects of LY293111 and ONO-1078 independent of blocking their receptors.

  20. Insulin receptor substrates 1 and 2 but not Shc can activate the insulin receptor independent of insulin and induce proliferation in CHO-IR cells

    SciTech Connect

    Niessen, Markus . E-mail: markus.niessen@usz.ch; Jaschinski, Frank; Item, Flurin; McNamara, Morgan P.; Spinas, Giatgen A.; Trueb, Thomas

    2007-02-15

    Ligand-activated insulin receptor (IR) attracts and phosphorylates various substrates such as insulin receptor substrates 1-4 (IRS) and Shc. To investigate how binding affinity for substrate affects signalling we generated chimeric receptors with the {beta}-chain of the insulin receptor containing NPXY motives with different affinities for receptor substrates. We found that the extent of receptor tyrosine phosphorylation positively correlates with binding affinity towards IRS1/2 but not towards Shc. Moreover, overexpression of IRS1 or IRS2 but not of Shc increased IR tyrosine phosphorylation in a dose-dependent manner, also independent of insulin. Molecular truncations of IRS1 revealed that neither the isolated PH and PTB domains nor the C-terminus with the tyrosine phosphorylation sites alone are sufficient for substrate-dependent receptor activation. Overexpression of IRS1 and IRS2 impaired insulin-induced internalization of the IR in a dose-dependent manner suggesting that IRS proteins prevent endosome-associated receptor dephosphorylation/inactivation. IRS1 and IRS2 could therefore target the activated IR to different cellular compartments. Overexpression of IRS1 and IRS2 inhibited insulin-stimulated activation of the MAP kinases Erk1/2 while it increased/induced activation of Akt/PKB. Finally, overexpression of IRS1 and IRS2 but not of Shc induced DNA synthesis in starved CHO-IR cells independent of exogenous growth factors. Our results demonstrate that variations in cellular IRS1 and IRS2 concentration affect insulin signalling both upstream and downstream and that IRS proteins could play instructive rather than just permissive roles in signal transmission.

  1. Neuroprotective effect of WIN55,212-2 against 3-nitropropionic acid-induced toxicity in the rat brain: involvement of CB1 and NMDA receptors

    PubMed Central

    Maya-López, Marisol; Colín-González, Ana Laura; Aguilera, Gabriela; de Lima, María Eduarda; Colpo-Ceolin, Ana; Rangel-López, Edgar; Villeda-Hernández, Juana; Rembao-Bojórquez, Daniel; Túnez, Isaac; Luna-López, Armando; Lazzarini-Lechuga, Roberto; González-Puertos, Viridiana Yazmín; Posadas-Rodríguez, Pedro; Silva-Palacios, Alejandro; Königsberg, Mina; Santamaría, Abel

    2017-01-01

    The endocannabinoid system (ECS), and agonists acting on cannabinoid receptors (CBr), are known to regulate several physiological events in the brain, including modulatory actions on excitatory events probably through N-methyl-D-aspartate receptor (NMDAr) activity. Actually, CBr agonists can be neuroprotective. The synthetic CBr agonist WIN55,212-2 acts mainly on CB1 receptor. In turn, the mitochondrial toxin 3-nitropropionic acid (3-NP) produces striatal alterations in rats similar to those observed in the brain of Huntington’s disease patients. Herein, the effects of WIN55,212-2 were tested on different endpoints of the 3-NP-induced toxicity in rat brain synaptosomes and striatal tissue. Motor activity was also evaluated. The 3-NP (1 mM)-induced mitochondrial dysfunction and lipid peroxidation was attenuated by WIN55,212-2 (1 µM) in synaptosomal fractions. The intrastriatal bilateral injection of 3-NP (500 nmol/µL) to rats increased lipid peroxidation and locomotor activity, augmented the rate of cell damage, and decreased the striatal density of neuronal cells. These alterations were accompanied by transcriptional changes in the NMDA (NR1 subunit) content. The administration of WIN55212-2 (1 mg/kg, i.p.) to rats for six consecutive days, before the 3-NP injection, exerted preventive effects on all alterations elicited by the toxin. The prevention of the 3-NP-induced NR1 transcriptional alterations by the CBr agonist together with the increase of CB1 content suggest an early reduction of the excitotoxic process via CBr activation. Our results demonstrate a protective role of WIN55,212-2 on the 3-NP-induced striatal neurotoxicity that could be partially related to the ECS stimulation and induction of NMDAr hypofunction, representing an effective therapeutic strategy at the experimental level for further studies. PMID:28337258

  2. Neuroprotective effect of WIN55,212-2 against 3-nitropropionic acid-induced toxicity in the rat brain: involvement of CB1 and NMDA receptors.

    PubMed

    Maya-López, Marisol; Colín-González, Ana Laura; Aguilera, Gabriela; de Lima, María Eduarda; Colpo-Ceolin, Ana; Rangel-López, Edgar; Villeda-Hernández, Juana; Rembao-Bojórquez, Daniel; Túnez, Isaac; Luna-López, Armando; Lazzarini-Lechuga, Roberto; González-Puertos, Viridiana Yazmín; Posadas-Rodríguez, Pedro; Silva-Palacios, Alejandro; Königsberg, Mina; Santamaría, Abel

    2017-01-01

    The endocannabinoid system (ECS), and agonists acting on cannabinoid receptors (CBr), are known to regulate several physiological events in the brain, including modulatory actions on excitatory events probably through N-methyl-D-aspartate receptor (NMDAr) activity. Actually, CBr agonists can be neuroprotective. The synthetic CBr agonist WIN55,212-2 acts mainly on CB1 receptor. In turn, the mitochondrial toxin 3-nitropropionic acid (3-NP) produces striatal alterations in rats similar to those observed in the brain of Huntington's disease patients. Herein, the effects of WIN55,212-2 were tested on different endpoints of the 3-NP-induced toxicity in rat brain synaptosomes and striatal tissue. Motor activity was also evaluated. The 3-NP (1 mM)-induced mitochondrial dysfunction and lipid peroxidation was attenuated by WIN55,212-2 (1 µM) in synaptosomal fractions. The intrastriatal bilateral injection of 3-NP (500 nmol/µL) to rats increased lipid peroxidation and locomotor activity, augmented the rate of cell damage, and decreased the striatal density of neuronal cells. These alterations were accompanied by transcriptional changes in the NMDA (NR1 subunit) content. The administration of WIN55212-2 (1 mg/kg, i.p.) to rats for six consecutive days, before the 3-NP injection, exerted preventive effects on all alterations elicited by the toxin. The prevention of the 3-NP-induced NR1 transcriptional alterations by the CBr agonist together with the increase of CB1 content suggest an early reduction of the excitotoxic process via CBr activation. Our results demonstrate a protective role of WIN55,212-2 on the 3-NP-induced striatal neurotoxicity that could be partially related to the ECS stimulation and induction of NMDAr hypofunction, representing an effective therapeutic strategy at the experimental level for further studies.

  3. Disruption of PTH Receptor 1 in T Cells Protects against PTH-Induced Bone Loss

    PubMed Central

    Tawfeek, Hesham; Bedi, Brahmchetna; Li, Jau-Yi; Adams, Jonathan; Kobayashi, Tatsuya; Weitzmann, M. Neale; Kronenberg, Henry M.; Pacifici, Roberto

    2010-01-01

    Background Hyperparathyroidism in humans and continuous parathyroid hormone (cPTH) treatment in mice cause bone loss by regulating the production of RANKL and OPG by stromal cells (SCs) and osteoblasts (OBs). Recently, it has been reported that T cells are required for cPTH to induce bone loss as the binding of the T cell costimulatory molecule CD40L to SC receptor CD40 augments SC sensitivity to cPTH. However it is unknown whether direct PTH stimulation of T cells is required for cPTH to induce bone loss, and whether T cells contribute to the bone catabolic activity of PTH with mechanisms other than induction of CD40 signaling in SCs. Methodology/Principal Findings Here we show that silencing of PTH receptor 1 (PPR) in T cells blocks the bone loss and the osteoclastic expansion induced by cPTH, thus demonstrating that PPR signaling in T cells is central for PTH-induced reduction of bone mass. Mechanistic studies revealed that PTH activation of the T cell PPR stimulates T cell production of the osteoclastogenic cytokine tumor necrosis factor α (TNF). Attesting to the relevance of this effect, disruption of T cell TNF production prevents PTH-induced bone loss. We also show that a novel mechanism by which TNF mediates PTH induced osteoclast formation is upregulation of CD40 expression in SCs, which increases their RANKL/OPG production ratio. Conclusions/Significance These findings demonstrate that PPR signaling in T cells plays an essential role in PTH induced bone loss by promoting T cell production of TNF. A previously unknown effect of TNF is to increase SC expression of CD40, which in turn increases SC osteoclastogenic activity by upregulating their RANKL/OPG production ratio. PPR-dependent stimulation of TNF production by T cells and the resulting TNF regulation of CD40 signaling in SCs are potential new therapeutic targets for the bone loss of hyperparathyroidism. PMID:20808842

  4. Phenylarsine oxide-induced increase in alveolar macrophage surface receptors: evidence for fusion of internal receptor pools with the cell surface

    PubMed Central

    1985-01-01

    Rabbit alveolar macrophages which were treated at 0 degrees C with phenylarsine oxide and then incubated at 37 degrees C for 10 min exhibited a two- to threefold increase in surface receptor activity for macroglobulin.protease complexes, diferric transferrin, and mannose- terminal glycoproteins. Analysis of the concentration-dependence of ligand binding indicated that changes in ligand-binding activity were due to changes in receptor number rather than alterations in ligand- receptor affinity. Surface receptor number could also be increased by treatment of cells with three other sulfhydryl reagents, N- ethylmaleimide, p-chloromercurobenzoate, and iodoacetic acid. The increase in receptor activity was maximal after 10 min and decreased over the next hour. This decrease in cell-associated receptor activity was due to the release of large membrane vesicles which demonstrated a uniform buoyant density by isopycnic sucrose gradient centrifugation. Treatment of cells with phenylarsine oxide did not decrease the cellular content of lactate dehydrogenase or beta-galactosidase, indicating that cell integrity was maintained and lysosomal enzyme release did not occur. Our studies indicate that phenylarsine oxide treatment in the presence of extracellular Ca2+ results in the fusion of receptor-containing vesicles with the cell surface. PMID:2409094

  5. IL‐33 delivery induces serous cavity macrophage proliferation independent of interleukin‐4 receptor alpha

    PubMed Central

    Jackson‐Jones, Lucy H.; Rückerl, Dominik; Svedberg, Freya; Duncan, Sheelagh; Maizels, Rick M.; Sutherland, Tara E.; Jenkins, Stephen J.; McSorley, Henry J.; Bénézech, Cécile; MacDonald, Andrew S.

    2016-01-01

    IL‐33 plays an important role in the initiation of type‐2 immune responses, as well as the enhancement of type 2 effector functions. Engagement of the IL‐33 receptor on macrophages facilitates polarization to an alternative activation state by amplifying IL‐4 and IL‐13 signaling to IL‐4Rα. IL‐4 and IL‐13 also induce macrophage proliferation but IL‐33 involvement in this process has not been rigorously evaluated. As expected, in vivo delivery of IL‐33 induced IL‐4Rα‐dependent alternative macrophage activation in the serous cavities. IL‐33 delivery also induced macrophages to proliferate but, unexpectedly, this was independent of IL‐4Rα signaling. In a filarial nematode infection model in which IL‐4Rα‐dependent alternative activation and proliferation in the pleural cavity is well described, IL‐33R was essential for alternative activation but not macrophage proliferation. Similarly, during Alternaria alternata induced airway inflammation, which provokes strong IL‐33 responses, we observed that both IL‐4Rα and IL‐33R were required for alternative activation, while macrophage proliferation in the pleural cavity was still evident in the absence of either receptor alone. Our data show that IL‐33R and IL‐4Rα promote macrophage proliferation independently of each other, but both are essential for induction of alternative activation. PMID:27592711

  6. The aldosterone-mineralocorticoid receptor pathway exerts anti-inflammatory effects in endotoxin-induced uveitis.

    PubMed

    Bousquet, Elodie; Zhao, Min; Ly, André; Leroux Les Jardins, Guillaume; Goldenberg, Brigitte; Naud, Marie-Christine; Jonet, Laurent; Besson-Lescure, Bernadette; Jaisser, Frederic; Farman, Nicolette; De Kozak, Yvonne; Behar-Cohen, Francine

    2012-01-01

    We have previously shown that the eye is a mineralocorticoid-sensitive organ and we now question the role of mineralocorticoid receptor (MR) in ocular inflammation. The endotoxin-induced uveitis (EIU), a rat model of human intraocular inflammation, was induced by systemic administration of lipopolysaccharide (LPS). Evaluations were made 6 and 24 hours after intraocular injection of aldosterone (simultaneous to LPS injection). Three hours after onset of EIU, the MR and the glucocorticoid metabolizing enzyme 11-beta hydroxysteroid dehydrogenase type 2 (11β-HSD2) expression were down-regulated in iris/ciliary body and the corticosterone concentration was increased in aqueous humor, altering the normal MR/glucocorticoid receptor (GR) balance. At 24 hours, the GR expression was also decreased. In EIU, aldosterone reduced the intensity of clinical inflammation in a dose-dependent manner. The clinical benefit of aldosterone was abrogated in the presence of the MR antagonist (RU26752) and only partially with the GR antagonist (RU38486). Aldosterone reduced the release of inflammatory mediators (6 and 24 hours: TNF-α, IFN-γ, MIP-1α) in aqueous humor and the number of activated microglia/macrophages. Aldosterone partly prevented the uveitis-induced MR down-regulation. These results suggest that MR expression and activation in iris/ciliary body could protect the ocular structures against damages induced by EIU.

  7. G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy.

    PubMed

    White, James P; Wrann, Christiane D; Rao, Rajesh R; Nair, Sreekumaran K; Jedrychowski, Mark P; You, Jae-Sung; Martínez-Redondo, Vicente; Gygi, Steven P; Ruas, Jorge L; Hornberger, Troy A; Wu, Zhidan; Glass, David J; Piao, Xianhua; Spiegelman, Bruce M

    2014-11-04

    Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1α4) is a protein isoform derived by alternative splicing of the PGC1α mRNA and has been shown to promote muscle hypertrophy. We show here that G protein-coupled receptor 56 (GPR56) is a transcriptional target of PGC-1α4 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-1α4 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-1α4-induced muscle hypertrophy in vitro. Forced expression of GPR56 results in myotube hypertrophy through the expression of insulin-like growth factor 1, which is dependent on Gα12/13 signaling. A murine model of overload-induced muscle hypertrophy is associated with increased expression of both GPR56 and its ligand collagen type III, whereas genetic ablation of GPR56 expression attenuates overload-induced muscle hypertrophy and associated anabolic signaling. These data illustrate a signaling pathway through GPR56 which regulates muscle hypertrophy associated with resistance/loading-type exercise.

  8. Liver X receptor agonist prevents LPS-induced mastitis in mice.

    PubMed

    Fu, Yunhe; Tian, Yuan; Wei, Zhengkai; Liu, Hui; Song, Xiaojing; Liu, Wenbo; Zhang, Wenlong; Wang, Wei; Cao, Yongguo; Zhang, Naisheng

    2014-10-01

    Liver X receptor-α (LXR-α) which belongs to the nuclear receptor superfamily, is a ligand-activated transcription factor. Best known for its ability to regulate lipid metabolism and transport, LXRs have recently also been implicated in regulation of inflammatory response. The aim of this study was to investigate the preventive effects of synthetic LXR-α agonist T0901317 on LPS-induced mastitis in mice. The mouse model of mastitis was induced by injection of LPS through the duct of mammary gland. T0901317 was injected 1h before and 12h after induction of LPS intraperitoneally. The results showed that T0901317 significantly attenuated the infiltration of neutrophilic granulocytes, and the activation of myeloperoxidase (MPO); down-regulated the level of pro-inflammatory mediators including TNF-α, IL-1β, IL-6, COX-2 and PEG2; inhibited the phosphorylation of IκB-α and NF-κB p65, caused by LPS. Moreover, we report for the first time that LXR-α activation impaired LPS-induced mastitis. Taken together, these data indicated that T0901317 had protective effect on mastitis and the anti-inflammatory mechanism of T0901317 on LPS induced mastitis in mice may be due to its ability to inhibit NF-κB signaling pathway. LXR-α activation can be used as a therapeutic approach to treat mastitis.

  9. Involvement of the prostaglandin E receptor EP2 in paeoniflorin-induced human hepatoma cell apoptosis.

    PubMed

    Hu, Shanshan; Sun, Wuyi; Wei, Wei; Wang, Di; Jin, Juan; Wu, Jingjing; Chen, Jingyu; Wu, Huaxun; Wang, Qingtong

    2013-02-01

    Prostaglandin E2 (PGE2) has been shown to play an important role in tumor development and progression. PGE2 mediates its biological activity by binding any one of four prostanoid receptors (EP1 through EP4). The present study was designed to determine the role of the EP2 receptor during the proliferation and apoptosis of human HepG2 and SMMC-7721 hepatoma cell lines and the effect of paeoniflorin, a monoterpene glycoside. The proliferation of HepG2 and SMMC-7721 cells was determined by methyl thiazolyl tetrazolium after exposure to the selective EP2 receptor agonists butaprost and paeoniflorin. Apoptosis of HepG2 and SMMC-7721 cells was also quantified by flow cytometry with annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression levels of Bcl-2 and Bax were quantified by western blotting and immunohistochemistry. The expression of the EP2 receptor and cysteine-aspartic acid protease (caspase)-3 was determined by western blotting. Butaprost significantly increased proliferation in HepG2 and SMMC-7721 cells. Paeoniflorin significantly inhibited the proliferation of HepG2 and SMMC-7721 cells stimulated by butaprost at multiple time points (24, 48, and 72 h). Paeoniflorin induced apoptosis in HepG2 and SMMC-7721 cells, which was quantified by annexin-V and propidium iodide staining. Our results indicate that the expression of the EP2 receptor and Bcl-2 was significantly increased, whereas that of Bax and cleaved caspase-3 was decreased in HepG2 and SMMC-7721 cells after stimulation by butaprost. Paeoniflorin significantly decreased the expression of the EP2 receptor and Bcl-2 and increased Bax and caspase-3 activation in HepG2 and SMMC-7721 cells on addition of butaprost. Our results show that the PGE2 receptor subtype EP2 may play a vital role in the survival of both HepG2 and SMMC-7721 cells. Paeoniflorin, which may be a promising agent in the treatment of liver cancer, induced apoptosis in hepatocellular carcinoma cells by downregulating

  10. Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation

    SciTech Connect

    Sato, Chieri; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sano, Hajime

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer We investigated the role of S1P signaling for osteoblast differentiation. Black-Right-Pointing-Pointer Both S1P and FTY enhanced BMP-2-stimulated osteoblast differentiation by C2C12 cells. Black-Right-Pointing-Pointer S1P signaling enhanced BMP-2-stimulated Smad and ERK phosphorylation by C2C12 cells. Black-Right-Pointing-Pointer MEK/ERK signaling is a pathway underlying S1P signaling for osteoblast differentiation. -- Abstract: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P

  11. Anti-inflammatory effects of cannabinoid CB2 receptor activation in endotoxin-induced uveitis

    PubMed Central

    Toguri, J T; Lehmann, C; Laprairie, R B; Szczesniak, A M; Zhou, J; Denovan-Wright, E M; Kelly, M E M

    2014-01-01

    Background and PurposeCannabinoid CB2 receptors mediate immunomodulation. Here, we investigated the effects of CB2 receptor ligands on leukocyte-endothelial adhesion and inflammatory mediator release in experimental endotoxin-induced uveitis (EIU). Experimental ApproachEIU was induced by intraocular injection of lipopolysaccharide (LPS, 20 ng·μL−1). Effects of the CB2 receptor agonist, HU308 (1.5% topical), the CB2 receptor antagonist, AM630 (2.5 mg·kg−1 i.v.), or a combination of both compounds on leukocyte-endothelial interactions were measured hourly for 6 h in rat iridial vasculature using intravital microscopy. Anti-inflammatory actions of HU308 were compared with those of clinical treatments for uveitis - dexamethasone, prednisolone and nepafenac. Transcription factors (NF-κB, AP-1) and inflammatory mediators (cytokines, chemokines and adhesion molecules) were measured in iris and ciliary body tissue. Key ResultsLeukocyte-endothelium adherence was increased in iridial microvasculature between 4–6 h after LPS. HU308 reduced this effect after LPS injection and decreased pro-inflammatory mediators: TNF-α, IL-1β, IL-6, CCL5 and CXCL2. AM630 blocked the actions of HU-308, and increased leukocyte-endothelium adhesion. HU-308 decreased levels of the transcription factors NF-κB and AP-1, while AM630 increased levels of NF-κB. Topical treatments with dexamethasone, prednisolone or nepafenac, failed to alter leukocyte adhesion or mitigate LPS-induced increases in inflammatory mediators during the 6 h of EIU. Conclusion and ImplicationsActivation of CB2 receptors was anti-inflammatory in a model of acute EIU and involved a reduction in NF-κB, AP-1 and inflammatory mediators. CB2 receptors may be promising drug targets for the development of novel ocular anti-inflammatory agents. Linked ArticlesThis article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014

  12. Striatal dopamine and glutamate receptors modulate methamphetamine-induced cortical Fos expression

    PubMed Central

    Gross, Noah B.; Marshall, John F.

    2009-01-01

    Methamphetamine (mAMPH) is a psychostimulant drug that increases extracellular levels of monoamines throughout the brain. It has previously been observed that a single injection of mAMPH increases immediate early gene (IEG) expression in both the striatum and cerebral cortex. Moreover, this effect is modulated by dopamine and glutamate receptors since systemic administration of dopamine or glutamate antagonists has been found to alter mAMPH-induced striatal and cortical IEG expression. However, because dopamine and glutamate receptors are found in extra-striatal as well as striatal brain regions, studies employing systemic injection of dopamine or glutamate antagonists fail to localize the effects of mAMPH-induced activation. In the present experiments, the roles of striatal dopamine and glutamate receptors in mAMPH-induced gene expression in the striatum and cerebral cortex were examined. The nuclear expression of Fos, the protein product of the IEG c-fos, was quantified in both the striatum and the cortex of animals receiving intrastriatal dopamine or glutamate antagonist administration. Intrastriatal infusion of dopamine (D1 or D2) or glutamate [N-methyl-D-aspartic acid (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)] antagonists affected not only mAMPH-induced striatal, but also cortical, Fos expression. Overall, the effects of the antagonists occurred dose-dependently, in both the infused and non-infused hemispheres, with greater influences occurring in the infused hemisphere. Finally, unilateral intrastriatal infusion of dopamine or glutamate antagonists changed the behavior of the rats from characteristic mAMPH-induced stereotypy to rotation ipsilateral to the infusion. These results demonstrate that mAMPH’s actions on striatal dopamine and glutamate receptors modulate the widespread cortical activation induced by mAMPH. It is hypothesized that dopamine release from nigrostriatal terminals modulates activity within striatal

  13. Ouabain-induced perturbations in intracellular ionic homeostasis regulate death receptor-mediated apoptosis.

    PubMed

    Panayiotidis, Mihalis I; Franco, Rodrigo; Bortner, Carl D; Cidlowski, John A

    2010-07-01

    Apoptosis is defined by specific morphological and biochemical characteristics including cell shrinkage (termed apoptotic volume decrease), a process that results from the regulation of ion channels and plasma membrane transporter activity. The Na(+)-K(+)-ATPase is the predominant pump that controls cell volume and plasma membrane potential in cells and alterations in its function have been suggested to be associated with apoptosis. We report here that the Na(+)-K(+)-ATPase inhibitor ouabain, potentiates apoptosis in the human lymphoma Jurkat cells exposed to Fas ligand (FasL) or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) but not other apoptotic agents such as H(2)O(2), thapsigargin or UV-C implicating a role for the Na(+)-K(+)-ATPase in death receptor-induced apoptosis. Interestingly, ouabain also potentiated perturbations in cell Ca(2+) homeostasis only in conjunction with the apoptotic inducer FasL but not TRAIL. Ouabain did not affect alterations in the intracellular Ca(2+) levels in response to H(2)O(2), thapsigargin or UV-C. FasL-induced alterations in Ca(2+) were not abolished in Ca(2+)-free medium but incubation of cells with BAPTA-AM inhibited both Ca(2+) perturbations and the ouabain-induced potentiation of FasL-induced apoptosis. Our data suggest that the impairment of the Na(+)-K(+)-ATPase activity during apoptosis is linked to perturbations in cell Ca(2+) homeostasis that modulate apoptosis induced by the activation of Fas by FasL.

  14. Physiological and drug-induced changes in the glycogen content of mouse brain

    PubMed Central

    Hutchins, D. A.; Rogers, K. J.

    1970-01-01

    1. The effect of the method of killing on the concentration of glycogen in mouse brain was determined. The cerebral glycogen content of mice killed by immersion in liquid nitrogen did not differe significantly from that of animals decapitated and the heads immediately frozen. A delay before freezing led to the rapid loss of brain glycogen, with a 17% fall at 10 s and an 82% loss after 5 min. 2. Hyperglycaemia, induced by the administration of D-glucose, resulted in an 8·3% loss of brain glycogen after 120 min. Insulin hypoglycaemia produced a 10·7% fall in glycogen at 60 min followed by an 11·2% increase at 120 min. 3. Exposure to either high (32° C) or low (10° C) ambient temperatures caused a depletion of brain glycogen. 4. A circadian rhythm of brain glycogen concentration was found, with a nadir which was coincident with the peak of locomotor activity and body temperature. 5. Drugs from several pharmacological classes were studied for their in vivo effect on the concentration of glycogen in mouse brain. 6. Brain glycogen was increased by all the depressant drugs tested, and by some drugs which had little effect on behaviour (diphenhydramine, phenytoin and propranolol), or which caused excitation (caffeine and nialamide). 7. Glycogen was depleted only by amphetamine-like compounds or by bemegride-induced convulsions. 8. The results are discussed with particular reference to the possible relation between catecholamines and glycogen metabolism in the brain. PMID:5420149

  15. Directed evolution of a soluble human DR3 receptor for the inhibition of TL1A induced cytokine secretion

    PubMed Central

    Levin, Itay; Zaretsky, Marianna; Aharoni, Amir

    2017-01-01

    TNF-like 1A (TL1A) is a cytokine belonging to the TNF superfamily that promotes inflammation in autoimmune diseases. Inhibiting the interaction of TL1A with the endogenous death-domain receptor 3 (DR3) offers a therapeutic approach for treating TL1A-induced autoimmune diseases. Here, we generated improved DR3 variants showing increased TL1A binding affinity and stability using a directed evolution approach. Given the high cysteine content and post-translational modification of DR3, we employed yeast surface display and expression in mammalian cell lines for screening, expression and characterization of improved DR3 variants. A cell-based assay performed with the human TF-1 cell line and CD4+ T cells showed that two improved DR3 mutants efficiently inhibited TL1A-induced cell death and secretion of IFN-γ, respectively. These DR3 mutants can be used as drug candidates for the treatment of inflammatory bowel diseases and for other autoimmune diseases, including rheumatic arthritis and asthma. PMID:28278297

  16. The critical role of spinal 5-HT7 receptors in opioid and non-opioid type stress-induced analgesia.

    PubMed

    Yesilyurt, Ozgur; Seyrek, Melik; Tasdemir, Serdar; Kahraman, Serdar; Deveci, Mehmet Salih; Karakus, Emre; Halici, Zekai; Dogrul, Ahmet

    2015-09-05

    The opioid and non-opioid types of stress-induced analgesia have been well defined. One of the non-opioid type involve the endocannabinoid system. We previously reported that the spinal serotonin 7 receptor (5-HT7) blockers inhibit both morphine and cannabinoid-induced analgesia, thus we hypothesized that descending serotonergic pathways-spinal 5-HT7 receptor loop might contribute to stress-induced analgesia. Stress-induced analgesia was induced with warm (32°C) or cold (20°C) water swim stress in male Balb-C mice. The effects of intrathecal injection of a selective 5-HT7 receptor antagonist, SB 269970, of the denervation of serotonergic neurons by intrathecal administration of 5,7-dihydroxytryptamine (5,7-DHT) and of lesions of the dorsolateral funiculus on opioid and non-opioid type stress-induced analgesia were evaluated with the tail-flick and hot plate tests. The expression of 5-HT7 receptors mRNA in the dorsal lumbar region of spinal cord were analyzed by RT-PCR following spinal serotonin depletion or dorsolateral funiculus lesion. The effects of the selective 5-HT7 receptor agonists LP 44 and AS 19 were tested on nociception. Intrathecal SB 269970 blocked both opioid and non-opioid type stress-induced analgesia. Dorsolateral funiculus lesion or denervation of the spinal serotonergic neurons resulted in a marked decrease in 5-HT7 receptor expression in the dorsal lumbar spinal cord, accompanied by inhibition of opioid and non-opioid type stress-induced analgesia. However, the systemic or intrathecal LP 44 and AS 19 alone did not produce analgesia in unstressed mice. These results indicate that descending serotonergic pathways and the spinal 5-HT7 receptor loop play a crucial role in mediating both opioid and non-opioid type stress-induced analgesia.

  17. Evidence for epidermal growth factor (EGF)-induced intermolecular autophosphorylation of the EGF receptors in living cells.

    PubMed Central

    Honegger, A M; Schmidt, A; Ullrich, A; Schlessinger, J

    1990-01-01

    In response to epidermal growth factor (EGF) stimulation, the intrinsic protein tyrosine kinase of EGF receptor is activated, leading to tyrosine phosphorylation of several cellular substrate proteins, including the EGF receptor molecule itself. To test the mechanism of EGF receptor autophosphorylation in living cells, we established transfected cell lines coexpressing a kinase-negative point mutant of EGF receptor (K721A) with an active EGF receptor mutant lacking 63 amino acids from its carboxy terminus. The addition of EGF to these cells caused tyrosine phosphorylation of the kinase-negative mutant by the active receptor molecule, demonstrating EGF receptor cross-phosphorylation in living cells. After internalization the kinase-negative mutant and CD63 have separate trafficking pathways. This limits their association and the extent of cross-phosphorylation of K721A by CD63. The coexpression of the kinase-negative mutant together with active EGF receptors in the same cells suppressed the mitogenic response toward EGF as compared with that in cells that express active receptors alone. The presence of the kinase-negative mutant functions as a negative dominant mutation suppressing the response of active EGF receptors, probably by interfering with EGF-induced signal transduction. It appears, therefore, that crucial events of signal transduction occur before K721A and active EGF receptors are separated by their different endocytic itineraries. Images PMID:2164634

  18. Sucrose-induced Receptor Kinase SIRK1 Regulates a Plasma Membrane Aquaporin in Arabidopsis*

    PubMed Central

    Wu, Xu Na; Sanchez Rodriguez, Clara; Pertl-Obermeyer, Heidi; Obermeyer, Gerhard; Schulze, Waltraud X.

    2013-01-01

    The transmembrane receptor kinase family is the largest protein kinase family in Arabidopsis, and it contains the highest fraction of proteins with yet uncharacterized functions. Here, we present functions of SIRK1, a receptor kinase that was previously identified with rapid transient phosphorylation after sucrose resupply to sucrose-starved seedlings. SIRK1 was found to be an active kinase with increasing activity in the presence of an external sucrose supply. In sirk1 T-DNA insertional mutants, the sucrose-induced phosphorylation patterns of several membrane proteins were strongly reduced; in particular, pore-gating phosphorylation sites in aquaporins were affected. SIRK1-GFP fusions were found to directly interact with aquaporins in affinity pull-down experiments on microsomal membrane vesicles. Furthermore, protoplast swelling assays of sirk1 mutants and SIRK1-GFP expressing lines confirmed a direct functional interaction of receptor kinase SIRK1 and aquaporins as substrates for phosphorylation. A lack of SIRK1 expression resulted in the failure of mutant protoplasts to control water channel activity upon changes in external sucrose concentrations. We propose that SIRK1 is involved in the regulation of sucrose-specific osmotic responses through direct interaction with and activation of an aquaporin via phosphorylation and that the duration of this response is controlled by phosphorylation-dependent receptor internalization. PMID:23820729

  19. Fibroblast growth factor signalling induces loss of progesterone receptor in breast cancer cells

    PubMed Central

    Piasecka, Dominika; Kitowska, Kamila; Czaplinska, Dominika; Mieczkowski, Kamil; Mieszkowska, Magdalena; Turczyk, Lukasz; Skladanowski, Andrzej C.; Zaczek, Anna J.; Biernat, Wojciech; Kordek, Radzislaw; Romanska, Hanna M.; Sadej, Rafal

    2016-01-01

    We have recently demonstrated that, fibroblast growth factor 2 (FGFR2), signalling via ribosomal S6 kinase 2 (RSK2), promotes progression of breast cancer (BCa). Loss of progesterone receptor (PR), whose activity in BCa cells can be stimulated by growth factor receptors (GFRs), is associated with poor patient outcome. Here we showed that FGF7/FGFR2 triggered phosphorylation of PR at Ser294, PR ubiquitination and subsequent receptor`s degradation via the 26S proteasome pathway in BCa cells. We further demonstrated that RSK2 mediated FGF7/FGFR2-induced PR downregulation. In addition, a strong synergistic effect of FGF7 and progesterone (Pg), reflected in the enhanced anchorage-independent growth and cell migration, was observed. Analysis of clinical material demonstrated that expression of PR inversely correlated with activated RSK (RSK-P) (p = 0.016). Patients with RSK-P(+)/PR(–) tumours had 3.629-fold higher risk of recurrence (p = 0.002), when compared with the rest of the cohort. Moreover, RSK-P(+)/PR(–) phenotype was shown as an independent prognostic factor (p = 0.006). These results indicate that the FGF7/FGFR2-RSK2 axis promotes PR turnover and activity, which may sensitize BCa cells to stromal stimuli and contribute to the progression toward steroid hormone negative BCa. PMID:27852068

  20. Chemotherapy-induced prospective memory impairment in breast cancer patients with different hormone receptor expression

    PubMed Central

    Li, Wen; Gan, Chen; Lv, Yue; Wang, Shanghu; Cheng, Huaidong

    2017-01-01

    Abstract This study aimed to investigate prospective memory impairment in patients with breast cancer with different expression of hormone receptors, including the estrogen receptor (ER) and the progesterone receptor (PR). A total of 120 patients with breast cancer who underwent chemotherapy following surgery were divided into 2 groups. The A group included 60 patients with ER−/PR− status, and the B group included 60 patients with ER+/PR+ status. After 6 cycles of postoperative adjuvant chemotherapy, all patients were administered neuropsychological and prospective memory tests, such as the Mini-Mental State Examination (MMSE), verbal fluency test (VFT), and digit span test (DST), as well as examination of event-based prospective memory (EBPM) and time-based prospective memory (TBPM). As the neuropsychological background test results showed, there were no significant differences in MMSE, DST, and TBPM scores (∗:P > 0.05) between patients with breast cancer in the ER−/PR− and ER+/PR+ groups, while the VFT and EBPM scores were significantly greater in patients with breast cancer with ER+/PR+ status than in those with ER−/PR− status (∗∗: P < 0.01), indicating that patients with ER−/PR− status have significant impairment in EBPM, although not in TBPM. The results of the present study indicate that different hormone receptor expression in patients with breast cancer may be associated with heterogeneity of chemotherapy-induced prospective memory impairment. PMID:28353608

  1. Nicotine and Nicotinic Receptor Drugs: Potential for Parkinson's Disease and Drug-Induced Movement Disorders.

    PubMed

    Quik, Maryka; Bordia, Tanuja; Zhang, Danhui; Perez, Xiomara A

    2015-01-01

    Parkinson's disease is a progressive neurodegenerative disorder associated with tremor, rigidity, and bradykinesia, as well as nonmotor symptoms including autonomic impairments, olfactory dysfunction, sleep disturbances, depression, and dementia. Although the major neurological deficit is a loss of nigrostriatal dopaminergic neurons, multiple neurotransmitters systems are compromised in Parkinson's disease. Consistent with this observation, dopamine replacement therapy dramatically improves Parkinson's disease motor symptoms. Additionally, drugs targeting the serotonergic, glutamatergic, adenosine, and other neurotransmitter systems may be beneficial. Recent evidence also indicates that nicotinic cholinergic drugs may be useful for the management of Parkinson's disease. This possibility initially arose from the results of epidemiological studies, which showed that smoking was associated with a decreased incidence of Parkinson's disease, an effect mediated in part by the nicotine in smoke. Further evidence for this idea stemmed from preclinical studies which showed that nicotine administration reduced nigrostriatal damage in parkinsonian rodents and monkeys. In addition to a potential neuroprotective role, emerging work indicates that nicotinic receptor drugs improve the abnormal involuntary movements or dyskinesias that arise as a side effect of l-dopa treatment, the gold standard therapy for Parkinson's disease. Both nicotine and nicotinic receptor drugs reduced l-dopa-induced dyskinesias by over 50% in parkinsonian rodent and monkey models. Notably, nicotine also attenuated the abnormal involuntary movements or tardive dyskinesias that arise with antipsychotic treatment. These observations, coupled with reports that nicotinic receptor drugs have procognitive and antidepressant effects, suggest that central nervous system (CNS) nicotinic receptors may represent useful targets for the treatment of movement disorders.

  2. Habituation deficits induced by metabotropic glutamate receptors 2/3 receptor blockade in mice: reversal by antipsychotic drugs.

    PubMed

    Bespalov, Anton; Jongen-Rêlo, Ana-Lucia; van Gaalen, Marcel; Harich, Silke; Schoemaker, Hans; Gross, Gerhard

    2007-02-01

    Cortical metabotropic glutamate receptors (mGluRs) seem to be involved in habituation of simple stimulus-bound behaviors (e.g., habituation to acoustic startle or odor-elicited orienting response). Habituation deficits may contribute to the cognitive symptoms of schizophrenia. In the present study, male NMRI mice were injected with mGluR2/3 antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropyl-1-yl)-3-(xanth-9-yl)propanoic acid (LY-341495) 30 min before being placed into novel arenas for automatic motor activity recording (2-h sessions). Administration of LY-341495 (1-10 mg/kg s.c.) dose-dependently prevented the habituation of the locomotor activity. Effects of LY-341495 (10 mg/kg) were fully and dose-dependently reversed by i.p. administration of haloperidol (0.03-0.3 mg/kg), clozapine (1-10 mg/kg), risperidone (0.01-0.1 mg/kg), olanzapine (0.3-3 mg/kg), aripiprazole (1-10 mg/kg), and sulpiride (3-30 mg/kg), each of which was given 15 min before the test. Effects of antipsychotic drugs were observed at the dose levels that did not affect spontaneous motor activity. LY-341495-induced delayed hyperactivity was also partially attenuated by lithium (50-200 mg/kg), amisulpride (1-10 mg/kg), and the selective dopamine D3 antagonist trans-N-[4-[2-(6-cyano-1,2,3,4-tetrahydroisoquinolin-2-yl)ethyl]cyclohexyl]-4-quinolinecarboxamide (SB-277011A; 3-30 mg/kg). Application of diazepam, imipramine, or several agonists and/or antagonists acting at various receptors that are thought to be relevant for antipsychotic treatment [e.g., 5-hydroxytryptamine (5-HT)(2A), 5-HT(3), and 5-HT(6) antagonists; 5-HT(1A) agonist; D4 antagonist; CB1 antagonist; ampakines; and glycine transporter inhibitor) had no appreciable effects. Thus, behavioral deficits induced by mGluR2/3 blockade (such as delayed motor hyperactivity) are selectively reversed by clinically used antipsychotic drugs.

  3. Dopamine-Induced Apoptosis of Lactotropes Is Mediated by the Short Isoform of D2 Receptor

    PubMed Central

    Radl, Daniela Betiana; Ferraris, Jimena; Boti, Valeria; Seilicovich, Adriana; Sarkar, Dipak Kumar; Pisera, Daniel

    2011-01-01

    Dopamine, through D2 receptor (D2R), is the major regulator of lactotrope function in the anterior pituitary gland. Both D2R isoforms, long (D2L) and short (D2S), are expressed in lactotropes. Although both isoforms can transduce dopamine signal, they differ in the mechanism that leads to cell response. The administration of D2R agonists, such as cabergoline, is the main pharmacological treatment for prolactinomas, but resistance to these drugs exists, which has been associated with alterations in D2R expression. We previously reported that dopamine and cabergoline induce apoptosis of lactotropes in primary culture in an estrogen-dependent manner. In this study we used an in vivo model to confirm the permissive action of estradiol in the apoptosis of anterior pituitary cells induced by D2R agonists. Administration of cabergoline to female rats induced apoptosis, measured by Annexin-V staining, in anterior pituitary gland from estradiol-treated rats but not from ovariectomized rats. To evaluate the participation of D2R isoforms in the apoptosis induced by dopamine we used lactotrope-derived PR1 cells stably transfected with expression vectors encoding D2L or D2S receptors. In the presence of estradiol, dopamine induced apoptosis, determined by ELISA and TUNEL assay, only in PR1-D2S cells. To study the role of p38 MAPK in apoptosis induced by D2R activation, anterior pituitary cells from primary culture or PR1-D2S were incubated with an inhibitor of the p38 MAPK pathway (SB203850). SB203580 blocked the apoptotic effect of D2R activation in lactotropes from primary cultures and PR1-D2S cells. Dopamine also induced p38 MAPK phosphorylation, determined by western blot, in PR1-D2S cells and estradiol enhanced this effect. These data suggest that, in the presence of estradiol, D2R agonists induce apoptosis of lactotropes by their interaction with D2S receptors and that p38 MAPK is involved in this process. PMID:21464994

  4. Naltrexone pretreatment blocks microwave-induced changes in central cholinergic receptors

    SciTech Connect

    Lai, H.; Carino, M.A.; Wen, Y.F.; Horita, A.; Guy, A.W. )

    1991-01-01

    Repeated exposure of rats to pulsed, circularly polarized microwaves (2,450-MHz, 2-microseconds pulses at 500 pps, power density 1 mW/cm2, at an averaged, whole-body SAR of 0.6 W/kg) induced biphasic changes in the concentration of muscarinic cholinergic receptors in the central nervous system. An increase in receptor concentration occurred in the hippocampus of rats subjected to ten 45-min sessions of microwave exposure, whereas a decrease in concentration was observed in the frontal cortex and hippocampus of rats exposed to ten 20-min sessions. These findings, which confirm earlier work in the authors' laboratory, were extended to include pretreatment of rats with the narcotic antagonist naltrexone (1 mg/kg, IP) before each session of exposure. The drug treatment blocked the microwave-induced changes in cholinergic receptors in the brain. These data further support the authors' hypothesis that endogenous opioids play a role in the effects of microwaves on central cholinergic systems.

  5. Increased expression of receptors for orexigenic factors in nodose ganglion of diet-induced obese rats.

    PubMed

    Paulino, Gabriel; Barbier de la Serre, Claire; Knotts, Trina A; Oort, Pieter J; Newman, John W; Adams, Sean H; Raybould, Helen E

    2009-04-01

    The vagal afferent pathway is important in short-term regulation of food intake, and decreased activation of this neural pathway with long-term ingestion of a high-fat diet may contribute to hyperphagic weight gain. We tested the hypothesis that expression of genes encoding receptors for orexigenic factors in vagal afferent neurons are increased by long-term ingestion of a high-fat diet, thus supporting orexigenic signals from the gut. Obesity-prone (DIO-P) rats fed a high-fat diet showed increased body weight and hyperleptinemia compared with low-fat diet-fed controls and high-fat diet-induced obesity-resistant (DIO-R) rats. Expression of the type I cannabinoid receptor and growth hormone secretagogue receptor 1a in the nodose ganglia was increased in DIO-P compared with low-fat diet-fed controls or DIO-R rats. Shifts in the balance between orexigenic and anorexigenic signals within the vagal afferent pathway may influence food intake and body weight gain induced by high fat diets.

  6. Increased expression of receptors for orexigenic factors in nodose ganglion of diet-induced obese rats

    PubMed Central

    Paulino, Gabriel; Barbier de la Serre, Claire; Knotts, Trina A.; Oort, Pieter J.; Newman, John W.; Adams, Sean H.; Raybould, Helen E.

    2009-01-01

    The vagal afferent pathway is important in short-term regulation of food intake, and decreased activation of this neural pathway with long-term ingestion of a high-fat diet may contribute to hyperphagic weight gain. We tested the hypothesis that expression of genes encoding receptors for orexigenic factors in vagal afferent neurons are increased by long-term ingestion of a high-fat diet, thus supporting orexigenic signals from the gut. Obesity-prone (DIO-P) rats fed a high-fat diet showed increased body weight and hyperleptinemia compared with low-fat diet-fed controls and high-fat diet-induced obesity-resistant (DIO-R) rats. Expression of the type I cannabinoid receptor and growth hormone secretagogue receptor 1a in the nodose ganglia was increased in DIO-P compared with low-fat diet-fed controls or DIO-R rats. Shifts in the balance between orexigenic and anorexigenic signals within the vagal afferent pathway may influence food intake and body weight gain induced by high fat diets. PMID:19190260

  7. Neuropeptide Y induces fasted pattern of duodenal motility via Y(2) receptors in conscious fed rats.

    PubMed

    Fujimiya, M; Itoh, E; Kihara, N; Yamamoto, I; Fujimura, M; Inui, A

    2000-01-01

    Neuropeptide Y (NPY), a 36-amino acid peptide abundantly expressed in the brain, has been implicated in the regulation of feeding and visceral functions. The present study was designed to investigate whether or not NPY specifically regulates duodenal motility. The manometric method was used to measure duodenal motility in conscious, freely moving rats. The rat duodenum showed phasic contractions mimicking the migrating motor complex in the fasted state that were replaced by irregular contractions after the ingestion of food. NPY powerfully affected the contractile activity after intracerebroventricular (i.c.v.) administration, changing fed (postprandial) patterns into phasic contractions characterized as fasted (interdigestive) patterns. This effect was mediated via receptors with pharmacological profiles similar to rat Y(2) and Y(4) receptors, although neither Y(1) nor Y(5) agonists had any effects on motility despite potent feeding-stimulatory effects. Immunoneutralization with anti-NPY antiserum administered i.c.v. abolished fasted patterns and induced fed-like motor activities. An i.c.v. dose of peptide YY produced a different effect from NPY, with increase in the motor activities of both fed and fasted patterns. These results indicate that fasted and fed motor activities are regulated processes and that NPY induces fasted activity through Y(2), and possibly Y(4), receptors, which may represent an integrated mechanism linked to the onset of feeding behavior.

  8. Signalling pathways induced by protease-activated receptors and integrins in T cells.

    PubMed

    Bar-Shavit, Rachel; Maoz, Miriam; Yongjun, Yin; Groysman, Maya; Dekel, Idit; Katzav, Shulamit

    2002-01-01

    Recent characterization of the thrombin receptor indicates that it plays a role in T-cell signalling pathways. However, little is known regarding the signalling events following stimulation of additional members of the protease-activated receptor (PAR) family, i.e. PAR2 and PAR3. Most of the postligand cascades are largely unknown. Here, we illustrate that in Jurkat T-leukaemic cells, activation of PAR1, PAR2 and PAR3 induce tyrosine phosphorylation of Vav1. This response was impaired in Jurkat T cells deficient in p56lck (JCaM1.6). Activation of PARs also led to an increase in tyrosine phosphorylation of ZAP-70 and SLP-76, two key proteins in T-cell receptor (TCR) signalling. We also demonstrated that p56lck is meaningful for integrin signalling. Thus, JCaM1.6 cells exhibited a marked reduction in their adherence to fibronectin-coated plates, as compared to the level of adherence of Jurkat T cells. While the phosphorylation of Vav1 in T cells is augmented following adhesion, no additional increase was noted following treatment of the adhered cells with PARs. Altogether, we have identified key components in the postligand-signalling cascade of PARs and integrins. Furthermore, we have identified Lck as a critical and possibly upstream component of PAR-induced Vav1 phosphorylation, as well as integrin activation, in Jurkat T cells.

  9. Glucocorticoid Receptor Activation Inhibits Chemotherapy-induced Cell Death in High-grade Serous Ovarian Carcinoma

    PubMed Central

    Stringer-Reasor, Erica M.; Baker, Gabrielle M.; Skor, Maxwell N.; Kocherginsky, Masha; Lengyel, Ernst; Fleming, Gini F.; Conzen, Suzanne D.

    2015-01-01

    Objectives To test the hypothesis that glucocorticoid receptor (GR) activation increases resistance to chemotherapy in high-grade serous ovarian cancer (HGS-OvCa) and that treatment with a GR antagonist will improve sensitivity to chemotherapy. Methods GR expression was assessed in OvCa cell lines by qRT-PCR and Western blot analysis and in xenografts and primary human tumors using immunohistochemistry (IHC). We also examined the effect of GR activation versus inhibition on chemotherapy-induced cytotoxicity in OvCa cell lines and in a xenograft model. Results With the exception of IGROV-1 cells, all OvCa cell lines tested had detectable GR expression by Western blot and qRT-PCR analysis. Twenty-five out of the 27 human primary HGS-OvCas examined expressed GR by IHC. No cell line expressed detectable progesterone receptor (PR) or androgen receptor (AR) by Western blot analysis. In vitro assays showed that in GR-positive HeyA8 and SKOV3 cells, dexamethasone (100 nM) treatment upregulated the pro-survival genes SGK1 and MKP1/DUSP1 and inhibited carboplatin/gemcitabine-induced cell death. Concurrent treatment with two GR antagonists, either mifepristone (100 nM) or CORT125134 (100 nM), partially reversed these effects. There was no anti-apoptotic effect of dexamethasone on chemotherapy-induced cell death in IGROV-1 cells, which did not have detectable GR protein. Mifepristone treatment alone was not cytotoxic in any cell line. HeyA8 OvCa xenograft studies demonstrated that adding mifepristone to carboplatin/gemcitabine increased tumor shri