Science.gov

Sample records for inhibit strongly stimulating

  1. Stimulated Superconductivity at Strong Coupling

    SciTech Connect

    Bao, Ning; Dong, Xi; Silverstein, Eva; Torroba, Gonzalo; /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC

    2011-08-12

    Stimulating a system with time dependent sources can enhance instabilities, thus increasing the critical temperature at which the system transitions to interesting low-temperature phases such as superconductivity or superfluidity. After reviewing this phenomenon in non-equilibrium BCS theory (and its marginal fermi liquid generalization) we analyze the effect in holographic superconductors. We exhibit a simple regime in which the transition temperature increases parametrically as we increase the frequency of the time-dependent source.

  2. Lactic Acid Bacteria Inducing a Weak Interleukin-12 and Tumor Necrosis Factor Alpha Response in Human Dendritic Cells Inhibit Strongly Stimulating Lactic Acid Bacteria but Act Synergistically with Gram-Negative Bacteria

    PubMed Central

    Zeuthen, Louise Hjerrild; Christensen, Hanne Risager; Frøkiær, Hanne

    2006-01-01

    The development and maintenance of immune homeostasis indispensably depend on signals from the gut flora. Lactic acid bacteria (LAB), which are gram-positive (G+) organisms, are plausible significant players and have received much attention. Gram-negative (G−) commensals, such as members of the family Enterobacteriaceae, may, however, be immunomodulators that are as important as G+ organisms but tend to be overlooked. Dendritic cells (DCs) are crucial immune regulators, and therefore, the present study aimed at investigating differences among human gut flora-derived LAB and G− bacteria in their patterns of DC polarization. Human monocyte-derived DCs were exposed to UV-killed bacteria, and cytokine secretion and surface marker expression were analyzed. Profound differences in the DC polarization patterns were found among the strains. While strains of LAB varied greatly in their capacity to induce interleukin-12 (IL-12) and tumor necrosis factor alpha (TNF-α), G− strains were consistently weak IL-12 and TNF-α inducers. All strains induced significant amounts of IL-10, but G− bacteria were far more potent IL-10 inducers than LAB. Interestingly, we found that when weakly IL-12- and TNF-α-inducing LAB and strong IL-12- and TNF-α-inducing LAB were mixed, the weakly IL-12- and TNF-α-inducing LAB efficiently inhibited otherwise strong IL-12- and TNF-α-inducing LAB, yet when weakly IL-12- and TNF-α-inducing LAB were mixed with G− bacteria, they synergistically induced IL-12 and TNF-α. Furthermore, strong IL-12- and TNF-α-inducing LAB efficiently up-regulated surface markers (CD40, CD83, CD86, and HLA-DR), which were inhibited by weakly IL-12- and TNF-α-inducing LAB. All G− bacteria potently up-regulated surface markers; however, these markers were not inhibited by weakly IL-12- and TNF-α-inducing LAB. These much divergent DC stimulation patterns among intestinal bacteria, which encompass both antagonistic and synergistic relationships, support the

  3. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites.

    PubMed

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-01-01

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca(2+) activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively. PMID:26988796

  4. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites

    PubMed Central

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-01-01

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca2+ activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca2+ activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively. DOI: http://dx.doi.org/10.7554/eLife.13598.001 PMID:26988796

  5. Stimulation by toll-like receptors inhibits osteoclast differentiation.

    PubMed

    Takami, Masamichi; Kim, Nacksung; Rho, Jaerang; Choi, Yongwon

    2002-08-01

    Osteoclasts, the cells capable of resorbing bone, are derived from hemopoietic precursor cells of monocyte-macrophage lineage. The same precursor cells can also give rise to macrophages and dendritic cells, which are essential for proper immune responses to various pathogens. Immune responses to microbial pathogens are often triggered because various microbial components induce the maturation and activation of immunoregulatory cells such as macrophages or dendritic cells by stimulating Toll-like receptors (TLRs). Since osteoclasts arise from the same precursors as macrophages, we tested whether TLRs play any role during osteoclast differentiation. We showed here that osteoclast precursors prepared from mouse bone marrow cells expressed all known murine TLRs (TLR1-TLR9). Moreover, various TLR ligands (e.g., peptidoglycan, poly(I:C) dsRNA, LPS, and CpG motif of unmethylated DNA, which act as ligands for TLR2, 3, 4, and 9, respectively) induced NF-kappa B activation and up-regulated TNF-alpha production in osteoclast precursor cells. Unexpectedly, however, TLR stimulation of osteoclast precursors by these microbial products strongly inhibited their differentiation into multinucleated, mature osteoclasts induced by TNF-related activation-induced cytokine. Rather, TLR stimulation maintained the phagocytic activity of osteoclast precursors in the presence of osteoclastogenic stimuli M-CSF and TNF-related activation-induced cytokine. Taken together, these results suggest that TLR stimulation of osteoclast precursors inhibits their differentiation into noninflammatory mature osteoclasts during microbial infection. This process favors immune responses and may be critical to prevent pathogenic effects of microbial invasion on bone. PMID:12133979

  6. Can intraurethral stimulation inhibit micturition reflex in normal female rats?

    PubMed Central

    Yu, Tian; Liao, Limin; Wyndaele, Jean Jacques

    2016-01-01

    ABSTRACT Objective The study was designed to determine the effect of low frequency (2.5Hz) intraurethral electrical stimulation on bladder capacity and maximum voiding pressures. Materials and Methods The experiments were conducted in 15 virgin female Sprague-Dawley rats (220–250g). The animals were anesthetized by intraperitoneal injection of urethane (1.5g/kg). Animal care and experimental procedures were reviewed and approved by the Institutional Animal Care and Use Committee of Antwerp University (code: 2013-50). Unipolar square pulses of 0.06mA were used to stimulate urethra at frequency of 2.5Hz (0.2ms pulse width) in order to evaluate the ability of intraurethral stimulation to inhibit bladder contractions. Continuous stimulation and intermittent stimulation with 5sec ‘‘on’’ and 5sec ‘‘off’’ duty cycle were applied during repeated saline cystometrograms (CMGs). Maximum voiding pressures (MVP) and bladder capacity were investigated to determine the inhibitory effect on bladder contraction induced by intraurethral stimulation. Results The continuous stimulation and intermittent stimulation significantly (p<0.05) decreased MVP and increased bladder capacity. There was no significant difference in MVP and bladder capacity between continuous and intermittent stimulation group. Conclusions The present results suggest that 2.5Hz continuous and intermittent intraurethral stimulation can inhibit micturition reflex, decrease MVP and increase bladder capacity. There was no significant difference in MVP and bladder capacity between continuous and intermittent stimulation group. PMID:27286128

  7. Mesencephalic stimulation elicits inhibition of phrenic nerve activity in cat.

    PubMed

    Gallman, E A; Lawing, W L; Millhorn, D E

    1991-05-01

    1. Previous work from this laboratory has indicated that the mesencephalon is the anatomical substrate for a mechanism capable of inhibiting central respiratory drive in glomectomized cats for periods of up to 1 h or more following brief exposure to systemic hypoxia; phrenic nerve activity was used as an index of central respiratory drive. 2. The present study was undertaken to further localize the region responsible for the observed post-hypoxic inhibition of respiratory drive. We studied the phrenic nerve response to stimulations of the mesencephalon in anaesthetized, paralysed peripherally chemo-denervated cats with end-expired PCO2 and body temperature servo-controlled. 3. Stimulations of two types were employed. Electrical stimulation allowed rapid determination of sites from which phrenic inhibition could be elicited. Microinjections of excitatory amino acids were used subsequently in order to confine excitation to neuronal cell bodies and not axons of passage. 4. Stimulation of discrete regions of the ventromedial aspect of the mesencephalon in the vicinity of the red nucleus produced substantial inhibition of phrenic activity which lasted up to 45 min. Stimulation of other areas of the mesencephalon either produced no phrenic inhibition or resulted in a slight stimulation of phrenic activity. 5. The results are discussed in the context of the central respiratory response to hypoxia. PMID:1676420

  8. Phosphatidic acid inhibits ceramide 1-phosphate-stimulated macrophage migration.

    PubMed

    Ouro, Alberto; Arana, Lide; Rivera, Io-Guané; Ordoñez, Marta; Gomez-Larrauri, Ana; Presa, Natalia; Simón, Jorge; Trueba, Miguel; Gangoiti, Patricia; Bittman, Robert; Gomez-Muñoz, Antonio

    2014-12-15

    Ceramide 1-phosphate (C1P) was recently demonstrated to potently induce cell migration. This action could only be observed when C1P was applied exogenously to cells in culture, and was inhibited by pertussis toxin. However, the mechanisms involved in this process are poorly understood. In this work, we found that phosphatidic acid (PA), which is structurally related to C1P, displaced radiolabeled C1P from its membrane-binding site and inhibited C1P-stimulated macrophage migration. This effect was independent of the saturated fatty acid chain length or the presence of a double bond in each of the fatty acyl chains of PA. Treatment of RAW264.7 macrophages with exogenous phospholipase D (PLD), an enzyme that produces PA from membrane phospholipids, also inhibited C1P-stimulated cell migration. Likewise, PA or exogenous PLD inhibited C1P-stimulated extracellularly regulated kinases (ERK) 1 and 2 phosphorylation, leading to inhibition of cell migration. However, PA did not inhibit C1P-stimulated Akt phosphorylation. It is concluded that PA is a physiological regulator of C1P-stimulated macrophage migration. These actions of PA may have important implications in the control of pathophysiological functions that are regulated by C1P, including inflammation and various cellular processes associated with cell migration such as organogenesis or tumor metastasis. PMID:25450673

  9. ATF3 inhibits PPARγ-stimulated transactivation in adipocyte cells

    SciTech Connect

    Jang, Min-Kyung; Jung, Myeong Ho

    2015-01-02

    Highlights: • ATF3 inhibits PPARγ-stimulated transcriptional activation. • ATF3 interacts with PPARγ. • ATF3 suppresses p300-mediated transcriptional coactivation. • ATF3 decreases the binding of PPARγ and recruitment of p300 to PPRE. - Abstract: Previously, we reported that activating transcription factor 3 (ATF3) downregulates peroxisome proliferator activated receptor (PPARγ) gene expression and inhibits adipocyte differentiation in 3T3-L1 cells. Here, we investigated another role of ATF3 on the regulation of PPARγ activity. ATF3 inhibited PPARγ-stimulated transactivation of PPARγ responsive element (PPRE)-containing reporter or GAL4/PPARγ chimeric reporter. Thus, ATF3 effectively repressed rosiglitazone-stimulated expression of adipocyte fatty acid binding protein (aP2), PPARγ target gene, in 3T3-L1 cells. Coimmunoprecipitation and GST pulldown assay demonstrated that ATF3 interacted with PPARγ. Accordingly, ATF3 prevented PPARγ from binding to PPRE on the aP2 promoter. Furthermore, ATF3 suppressed p300-mediated transcriptional coactivation of PPRE-containing reporter. Chromatin immunoprecipitation assay showed that overexpression of ATF3 blocked both binding of PPARγ and recruitment of p300 to PPRE on aP2 promoter induced by rosiglitazone treatment in 3T3-L1 cells. Taken together, these results suggest that ATF3 interacts with PPARγ and represses PPARγ-mediated transactivation through suppression of p300-stimulated coactivation in 3T3-L1 cells, which may play a role in inhibition of adipocyte differentiation.

  10. Inhibition of airway surface fluid absorption by cholinergic stimulation.

    PubMed

    Joo, Nam Soo; Krouse, Mauri E; Choi, Jae Young; Cho, Hyung-Ju; Wine, Jeffrey J

    2016-01-01

    In upper airways airway surface liquid (ASL) depth and clearance rates are both increased by fluid secretion. Secretion is opposed by fluid absorption, mainly via the epithelial sodium channel, ENaC. In static systems, increased fluid depth activates ENaC and decreased depth inhibits it, suggesting that secretion indirectly activates ENaC to reduce ASL depth. We propose an alternate mechanism in which cholinergic input, which causes copious airway gland secretion, also inhibits ENaC-mediated absorption. The conjoint action accelerates clearance, and the increased transport of mucus out of the airways restores ASL depth while cleansing the airways. We were intrigued by early reports of cholinergic inhibition of absorption by airways in some species. To reinvestigate this phenomenon, we studied inward short-circuit currents (Isc) in tracheal mucosa from human, sheep, pig, ferret, and rabbit and in two types of cultured cells. Basal Isc was inhibited 20-70% by the ENaC inhibitor, benzamil. Long-lasting inhibition of ENaC-dependent Isc was also produced by basolateral carbachol in all preparations except rabbit and the H441 cell line. Atropine inhibition produced a slow recovery or prevented inhibition if added before carbachol. The mechanism for inhibition was not determined and is most likely multi-factorial. However, its physiological significance is expected to be increased mucus clearance rates in cholinergically stimulated airways. PMID:26846701

  11. Inhibition of airway surface fluid absorption by cholinergic stimulation

    PubMed Central

    Joo, Nam Soo; Krouse, Mauri E.; Choi, Jae Young; Cho, Hyung-Ju; Wine, Jeffrey J.

    2016-01-01

    In upper airways airway surface liquid (ASL) depth and clearance rates are both increased by fluid secretion. Secretion is opposed by fluid absorption, mainly via the epithelial sodium channel, ENaC. In static systems, increased fluid depth activates ENaC and decreased depth inhibits it, suggesting that secretion indirectly activates ENaC to reduce ASL depth. We propose an alternate mechanism in which cholinergic input, which causes copious airway gland secretion, also inhibits ENaC-mediated absorption. The conjoint action accelerates clearance, and the increased transport of mucus out of the airways restores ASL depth while cleansing the airways. We were intrigued by early reports of cholinergic inhibition of absorption by airways in some species. To reinvestigate this phenomenon, we studied inward short-circuit currents (Isc) in tracheal mucosa from human, sheep, pig, ferret, and rabbit and in two types of cultured cells. Basal Isc was inhibited 20–70% by the ENaC inhibitor, benzamil. Long-lasting inhibition of ENaC-dependent Isc was also produced by basolateral carbachol in all preparations except rabbit and the H441 cell line. Atropine inhibition produced a slow recovery or prevented inhibition if added before carbachol. The mechanism for inhibition was not determined and is most likely multi-factorial. However, its physiological significance is expected to be increased mucus clearance rates in cholinergically stimulated airways. PMID:26846701

  12. Mechanism of Deep Brain Stimulation: Inhibition, Excitation, or Disruption?

    PubMed

    Chiken, Satomi; Nambu, Atsushi

    2016-06-01

    Deep brain stimulation (DBS), applying high-frequency electrical stimulation to deep brain structures, has now provided an effective therapeutic option for treatment of various neurological and psychiatric disorders. DBS targeting the internal segment of the globus pallidus, subthalamic nucleus, and thalamus is used to treat symptoms of movement disorders, such as Parkinson's disease, dystonia, and tremor. However, the mechanism underlying the beneficial effects of DBS remains poorly understood and is still under debate: Does DBS inhibit or excite local neuronal elements? In this short review, we would like to introduce our recent work on the physiological mechanism of DBS and propose an alternative explanation: DBS dissociates input and output signals, resulting in the disruption of abnormal information flow through the stimulation site. PMID:25888630

  13. Is Peroxiredoxin II's peroxidase activity strongly inhibited in human erythrocytes?

    PubMed

    Benfeitas, Rui; Selvaggio, Gianluca; Antunes, Fernando; Coelho, Pedro; Salvador, Armindo

    2014-10-01

    H2O2 elimination in human erythrocytes is mainly carried out by catalase (Cat), glutathione peroxidase (GPx1) and the more recently discovered peroxiredoxin 2 (Prx2). However, the contribution of Prx2 to H2O2 consumption is still unclear. Prx2's high reactivity with H2O2 (kPrx2=10×10(7) M(-1)s(-1), kCat =7×10(7) M(-1)s(-1), kGPx1 =4×10(7) M(-1)s(-1)) and high abundance ([Prx2]= 570µM, [Cat]= 32µM, [GPx1]= 1µM) suggest that under low H2O2 supply rates it should consume >99% of the H2O2. However, extensive evidence indicates that in intact erythrocytes Prx2 contributes no more than Cat to H2O2 consumption. In order for this to be attained, Prx2's effective rate constant with H2O2would have to be just ~10(5) M(-1)s(-1), much lower than that determined in multiple experiments with the purified proteins. Nevertheless, nearly all Prx2 is oxidized within 1min of exposing erythrocytes to a H2O2 bolus, which is inconsistent with an irreversible inhibition. A mathematical model of the H2O2 metabolism in human erythrocytes [Benfeitas et al. (2014) Free Radic. Biol. Med.] where Prx2 either has a low kPrx2 or is subject to a strong (>99%) but readily reversible inhibition achieves quantitative agreement with detailed experimental observations of the responses of the redox status of Prx2 in human erythrocytes and suggests functional advantages of this design (see companion abstract). By contrast, a variant where Prx2 is fully active with kPrx2=10(8) M(-1)s(-1) shows important qualitative discrepancies. Altogether, these results suggest that Prx2's peroxidase activity is strongly inhibited in human erythrocytes. We acknowledge fellowship SFRH/BD/51199/2010, grants PEst-C/SAU/LA0001/2013-2014, PEst-OE/QUI/UI0612/2013, PEst-OE/QUI/UI0313/2014, and FCOMP-01-0124-FEDER-020978 (PTDC/QUI-BIQ/119657/2010) co-financed by FEDER through the COMPETE program and by FCT. PMID:26461310

  14. Enhancing and inhibiting stimulated Brillouin scattering in photonic integrated circuits

    PubMed Central

    Merklein, Moritz; Kabakova, Irina V.; Büttner, Thomas F. S.; Choi, Duk-Yong; Luther-Davies, Barry; Madden, Stephen J.; Eggleton, Benjamin J.

    2015-01-01

    On-chip nonlinear optics is a thriving research field, which creates transformative opportunities for manipulating classical or quantum signals in small-footprint integrated devices. Since the length scales are short, nonlinear interactions need to be enhanced by exploiting materials with large nonlinearity in combination with high-Q resonators or slow-light structures. This, however, often results in simultaneous enhancement of competing nonlinear processes, which limit the efficiency and can cause signal distortion. Here, we exploit the frequency dependence of the optical density-of-states near the edge of a photonic bandgap to selectively enhance or inhibit nonlinear interactions on a chip. We demonstrate this concept for one of the strongest nonlinear effects, stimulated Brillouin scattering using a narrow-band one-dimensional photonic bandgap structure: a Bragg grating. The stimulated Brillouin scattering enhancement enables the generation of a 15-line Brillouin frequency comb. In the inhibition case, we achieve stimulated Brillouin scattering free operation at a power level twice the threshold. PMID:25736909

  15. Enhancing and inhibiting stimulated Brillouin scattering in photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Merklein, Moritz; Kabakova, Irina V.; Büttner, Thomas F. S.; Choi, Duk-Yong; Luther-Davies, Barry; Madden, Stephen J.; Eggleton, Benjamin J.

    2015-03-01

    On-chip nonlinear optics is a thriving research field, which creates transformative opportunities for manipulating classical or quantum signals in small-footprint integrated devices. Since the length scales are short, nonlinear interactions need to be enhanced by exploiting materials with large nonlinearity in combination with high-Q resonators or slow-light structures. This, however, often results in simultaneous enhancement of competing nonlinear processes, which limit the efficiency and can cause signal distortion. Here, we exploit the frequency dependence of the optical density-of-states near the edge of a photonic bandgap to selectively enhance or inhibit nonlinear interactions on a chip. We demonstrate this concept for one of the strongest nonlinear effects, stimulated Brillouin scattering using a narrow-band one-dimensional photonic bandgap structure: a Bragg grating. The stimulated Brillouin scattering enhancement enables the generation of a 15-line Brillouin frequency comb. In the inhibition case, we achieve stimulated Brillouin scattering free operation at a power level twice the threshold.

  16. Cadmium inhibits acid secretion in stimulated frog gastric mucosa

    SciTech Connect

    Gerbino, Andrea; Debellis, Lucantonio; Caroppo, Rosa; Curci, Silvana; Colella, Matilde

    2010-06-01

    Cadmium, a toxic environmental pollutant, affects the function of different organs such as lungs, liver and kidney. Less is known about its toxic effects on the gastric mucosa. The aim of this study was to investigate the mechanisms by which cadmium impacts on the physiology of gastric mucosa. To this end, intact amphibian mucosae were mounted in Ussing chambers and the rate of acid secretion, short circuit current (I{sub sc}), transepithelial potential (V{sub t}) and resistance (R{sub t}) were recorded in the continuous presence of cadmium. Addition of cadmium (20 {mu}M to 1 mM) on the serosal but not luminal side of the mucosae resulted in inhibition of acid secretion and increase in NPPB-sensitive, chloride-dependent short circuit current. Remarkably, cadmium exerted its effects only on histamine-stimulated tissues. Experiments with TPEN, a cell-permeant chelator for heavy metals, showed that cadmium acts from the intracellular side of the acid secreting cells. Furthermore, cadmium-induced inhibition of acid secretion and increase in I{sub sc} cannot be explained by an action on: 1) H{sub 2} histamine receptor, 2) Ca{sup 2+} signalling 3) adenylyl cyclase or 4) carbonic anhydrase. Conversely, cadmium was ineffective in the presence of the H{sup +}/K{sup +}-ATPase blocker omeprazole suggesting that the two compounds likely act on the same target. Our findings suggest that cadmium affects the functionality of histamine-stimulated gastric mucosa by inhibiting the H{sup +}/K{sup +}-ATPase from the intracellular side. These data shed new light on the toxic effect of this dangerous environmental pollutant and may result in new avenues for therapeutic intervention in acute and chronic intoxication.

  17. Stimulation of beta-adrenoceptors inhibits calcium-dependent potassium-channels in mouse macrophages

    SciTech Connect

    Rosati, C.; Hannaert, P.; Dausse, J.P.; Braquet, P.; Garay, R.

    1986-12-01

    K/sup +/ efflux in mouse macrophages exhibited a rate constant (k/sub k/) of 0.67 +/- 0.04 (h)/sup -1/. This was strongly stimulated by increasing concentrations of the Ca/sup 2 +/ ionophore A23187 up to a maximal value of 4.01 +/- 0.25 (h)/sup -1/ with an IC/sub 50/ of 7.6 +/- 1.9 ..mu..M. Similar results were obtained with the Ca/sup 2 +/ ionophore ionomycin. Binding experiments with /sup 3/H-dihydroalprenolol revealed a high density of beta-adrenergic receptors with apparent dissociation constant of 2.03 +/- 0.06 nM. Isoproterenol at a concentration of 10/sup -6/ -10/sup -5/ M induced a two- to threefold stimulation of endogenous levels of cyclic AMP (cAMP). A23187-stimulated K/sup +/ efflux was partially inhibited by (i) stimulation of adenylate cyclase with isoproterenol, forskolin or, PGE/sub 1/; (ii) exogenous cAMP; and (iii) inhibition of phosphodiesterase with MIX (1-methyl-3-isobutylxanthine). Maximal inhibition of K/sup +/ efflux was obtained by simultaneous addition of isoproterenol and MIX. In dose-response curves, the isoproterenol-sensitive K/sup +/ efflux was half-maximally inhibited (IC/sub 50/) with 2-5 x 10/sup -10/ M of isoproterenol concentration. Propranolol was able to completely block the effect of isoproterenol, with an IC/sub 50/ of about 1-2 x 10/sup -7/ M. Isoproterenol and MIX did not inhibit A23187-stimulated K/sup +/ efflux in an incubation medium where NaCl was replaced by sucrose (or choline), suggesting the involvement of an Na/sup +/:Ca/sup 2 +/ exchange mechanism. The results show that stimulation of beta-adrenoceptors in mouse macrophages counter balances the opening of K/sup +/ channels induced by the calcium ionophore A23187. This likely reflects a decrease in cytoslic free calcium content via a cAMP-mediated stimulation of Na/sup +/:Ca/sup 2 +/ exchange.

  18. Sphingolipids inhibit insulin and phorbol ester stimulated uptake of 2-deoxyglucose

    SciTech Connect

    Nelson, D.H.; Murray, D.K.

    1986-07-16

    Studies are presented demonstrating inhibition of both insulin and phorbol myristate acetate stimulated uptake of 2-deoxyglucose uptake by 3T3-L1 fibroblasts. Greatest inhibition of uptake was seen with sphinganine while sphingosine was also potent in this regard. Ceramide inhibited phorbol myristate acetate but not insulin stimulation of uptake. It is suggested that sphingolipid inhibition of glucose transport relates to the previously demonstrated effect of corticosteroids to increase membrane sphingomyelin and inhibit glucose transport.

  19. New, non-quinone fluorogeldanamycin derivatives strongly inhibit Hsp90.

    PubMed

    Hermane, Jekaterina; Bułyszko, Ilona; Eichner, Simone; Sasse, Florenz; Collisi, Wera; Poso, Antti; Schax, Emilia; Walter, Johanna-Gabriela; Scheper, Thomas; Kock, Klaus; Herrmann, Christian; Aliuos, Pooyan; Reuter, Günter; Zeilinger, Carsten; Kirschning, Andreas

    2015-01-19

    Streptomyces hygroscopicus is a natural producer of geldanamycin. Mutasynthetic supplementation of an AHBA-blocked mutant with all possible monofluoro 3-aminobenzoic acids provided new fluorogeldanamycins. These showed strong antiproliferative activity and inhibitory effects on human heat shock protein Hsp90. Binding to Hsp90 in the low nanomolar range was determined from molecular modelling, AFM analysis and by calorimetric studies. PMID:25572106

  20. Orf virus inhibits interferon stimulated gene expression and modulates the JAK/STAT signalling pathway.

    PubMed

    Harvey, Ryan; McCaughan, Catherine; Wise, Lyn M; Mercer, Andrew A; Fleming, Stephen B

    2015-10-01

    Interferons (IFNs) play a critical role as a first line of defence against viral infection. Activation of the Janus kinase/signal transducer and activation of transcription (JAK/STAT) pathway by IFNs leads to the production of IFN stimulated genes (ISGs) that block viral replication. The Parapoxvirus, Orf virus (ORFV) induces acute pustular skin lesions of sheep and goats and is transmissible to man. The virus replicates in keratinocytes that are the immune sentinels of skin. We investigated whether or not ORFV could block the expression of ISGs. The human gene GBP1 is stimulated exclusively by type II IFN while MxA is stimulated exclusively in response to type I IFNs. We found that GBP1 and MxA were strongly inhibited in ORFV infected HeLa cells stimulated with IFN-γ or IFN-α respectively. Furthermore we showed that ORFV inhibition of ISG expression was not affected by cells pretreated with adenosine N1-oxide (ANO), a molecule that inhibits poxvirus mRNA translation. This suggested that new viral gene synthesis was not required and that a virion structural protein was involved. We next investigated whether ORFV infection affected STAT1 phosphorylation in IFN-γ or IFN-α treated HeLa cells. We found that ORFV reduced the levels of phosphorylated STAT1 in a dose-dependent manner and was specific for Tyr701 but not Ser727. Treatment of cells with sodium vanadate suggested that a tyrosine phosphatase was responsible for dephosphorylating STAT1-p. ORFV encodes a factor, ORFV057, with homology to the vaccinia virus structural protein VH1 that impairs the JAK/STAT pathway by dephosphorylating STAT1. Our findings show that ORFV has the capability to block ISG expression and modulate the JAK/STAT signalling pathway. PMID:26113305

  1. Granulocyte colony-stimulating factor delays neutrophil apoptosis by inhibition of calpains upstream of caspase-3

    PubMed Central

    Drewniak, Agata; Groenewold, Vincent; van den Berg, Timo K.; Kuijpers, Taco W.

    2008-01-01

    Neutrophils have a very short life span and undergo apoptosis within 24 hours after leaving the bone marrow. Granulocyte colony-stimulating factor (G-CSF) is essential for the recruitment of fresh neutrophils from the bone marrow but also delays apoptosis of mature neutrophils. To determine the mechanism by which G-CSF inhibits neutrophil apoptosis, the kinetics of neutrophil apoptosis during 24 hours in the absence or presence of G-CSF were analyzed in vitro. G-CSF delayed neutrophil apoptosis for approximately 12 hours and inhibited caspase-9 and -3 activation, but had virtually no effect on caspase-8 and little effect on the release of proapoptotic proteins from the mitochondria. However, G-CSF strongly inhibited the activation of calcium-dependent cysteine proteases calpains, upstream of caspase-3, via apparent control of Ca2+-influx. Calpain inhibition resulted in the stabilization of the X-linked inhibitor of apoptosis (XIAP) and hence inhibited caspase-9 and -3 in human neutrophils. Thus, neutrophil apoptosis is controlled by G-CSF after initial activation of caspase-8 and mitochondrial permeabilization by the control of postmitochondrial calpain activity. PMID:18524991

  2. Brain sites mediating corticosteroid feedback inhibition of stimulated ACTH secretion

    SciTech Connect

    Jacobson, L.

    1989-01-01

    There is substantial evidence that the brain mediates stress-induced and circadian increases in ACTH secretion and that corticosteroid concentrations which normalize basal plasma ACTH are insufficient to normalize ACTH responses to circadian or stressful stimuli in adrenalectomized rats. To identify brain sites mediating corticosteroid inhibition of stimulated ACTH secretion, two approaches were used. The first compared brain ({sup 14}C)-2-deoxyglucose uptake in rats with differential ACTH responses to stress. Relative to sham-adrenalectomized (SHAM) rats, adrenalectomized rats replaced with low, constant corticosterone levels via a subcutaneous corticosterone pellet (B-PELLET) exhibited elevated and prolonged ACTH responses to a variety of stimuli. Adrenalectomized rate given a circadian corticosterone rhythm via corticosterone in their drinking water exhibited elevated ACTH levels immediately after stress, but unlike B-PELLET rats, terminated stress induced ACTH secretion normally relative to SHAMS. Therefore, the abnormal ACTH responses to stress in B-PELLET rats were due to the lack of both circadian variations and stress-induced increases in corticosterone. Hypoxia was selected as a standardized stimulus for correlating brain ({sup 14}C)-2-deoxyglucose uptake with ACTH secretion. In intact rats, increases in plasma ACTH and decreases in arterial PO{sub 2} correlated with the severity of hypoxia at arterial PCO{sub 2} below 60 mm Hg. Hypoxia PELLET vs. SHAM rats. However, in preliminary experiments, although hypoxia increased brain 2-deoxyglucose uptake in most brain regions, plasma ACTH correlated poorly with 2-deoxyglucose uptake at 12% and 10% O{sub 2}.

  3. MECHANISMS UNDERLYING ALC13 INHIBITION OF AGONIST-STIMULATED INOSITOL PHOSPHATE ACCUMULATION

    EPA Science Inventory

    Possible mechanisms of AlC13-induced inhibition of agonist-stimulated inositol phosphate (IP) accumulation were investigated using rat brain cortex slices, synaptosomes or homogenates. nder conditions in which AlC13 inhibits carbachol (CARB) stimulated IP accumulation (Gp-mediate...

  4. Inhibition by forskolin of insulin-stimulated glucose transport in L6 muscle cells.

    PubMed Central

    Klip, A; Ramlal, T; Douen, A G; Bilan, P J; Skorecki, K L

    1988-01-01

    The cardioactive diterpene forskolin is a known activator of adenylate cyclase, but recently a specific interaction of this compound with the glucose transporter has been identified that results in the inhibition of glucose transport in several human and rat cell types. We have compared the sensitivity of basal and insulin-stimulated hexose transport to inhibition by forskolin in skeletal muscle cells of the L6 line. Forskolin completely inhibited both basal and insulin-stimulated hexose transport when present during the transport assay. The inhibition of basal transport was completely reversible upon removal of the diterpene. In contrast, insulin-stimulated hexose transport did not recover, and basal transport levels were attained instead. This effect of inhibiting (or reversing) the insulin-stimulated fraction of transport is a novel effect of the diterpene. Forskolin treatment also inhibited the stimulated fraction of transport when the stimulus was by 4 beta-phorbol 12,13-dibutyrate, reversing back to basal levels. Half-maximal inhibition of the above-basal insulin-stimulated transport was achieved with 35-50 microM-forskolin, and maximal inhibition with 100 microM. Forskolin did not inhibit 125I-insulin binding under conditions where it caused significant inhibition of insulin-stimulated hexose transport. Forskolin significantly elevated the cyclic AMP levels in the cells; however its inhibitory effect on the above basal, insulin-stimulated fraction of hexose transport was not mediated by cyclic AMP since: (i) 8-bromo cyclic AMP and cholera toxin did not mimic this effect of the diterpene, (ii) significant decreases in cyclic AMP levels caused by 2',3'-dideoxyadenosine in the presence of forskolin did not prevent inhibition of insulin-stimulated hexose transport, (iii) isobutylmethylxanthine did not potentiate forskolin effects on glucose transport but did potentiate the elevation in cyclic AMP, and (iv) 1,9-dideoxyforskolin, which does not activate adenylate

  5. Phase-interfacial stimulated Raman scattering generated in strongly pumped water.

    PubMed

    Yuan, Hong; Gai, Baodong; Liu, Jinbo; Guo, Jingwei; Li, Hui; Hu, Shu; Deng, Liezheng; Jin, Yuqi; Sang, Fengting

    2016-07-15

    We have observed unusual blue-shifted radiations in water pumped by a strong 532-nm nanosecond laser. Properties including divergence, polarizations, and pulse shapes of the unusual radiations are measured and compared with those of the regular stimulated Raman scattering (SRS) in water. The unusual radiations are attributed to the parametric anti-Stokes SRS that occurs on the interface of water and ionization plasma (or gas) formed in the laser-induced breakdown of water. PMID:27420529

  6. Inhibition of CaMKK2 Stimulates Osteoblast Formation and Inhibits Osteoclast Differentiation

    PubMed Central

    Cary, Rachel L.; Waddell, Seid; Racioppi, Luigi; Long, Fanxin; Novack, Deborah V.; Voor, Michael J.; Sankar, Uma

    2013-01-01

    Bone remodeling, a physiological process characterized by bone formation by osteoblasts (OB) and resorption of pre-existing bone matrix by osteoclasts (OC), is vital for the maintenance of healthy bone tissue in adult humans. Imbalances in this vital process result in pathological conditions including osteoporosis. Owing to its initial asymptomatic nature, osteoporosis is often detected only after the patient has sustained significant bone loss or a fracture. Hence, anabolic therapeutics that stimulates bone accrual is in high clinical demand. Here we identify Ca2+/calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) as a potential target for such therapeutics, as its inhibition enhances OB differentiation and bone growth and suppresses OC differentiation. Mice null for CaMKK2 possess higher trabecular bone mass in their long bones, along with significantly more OBs and fewer multinuclear OCs. Whereas Camkk2−/− MSCs yield significantly higher numbers of OBs, bone marrow cells from Camkk2−/− mice produce fewer multinuclear OCs, in vitro. Acute inhibition of CaMKK2 by its selective, cell-permeable pharmacological inhibitor STO-609 also results in increased OB and diminished OC formation. Further, we find phospho-protein kinase A (PKA) and Ser133 phosphorylated form of cyclic adenosine monophosphate (cAMP) response element binding protein (pCREB) to be markedly elevated in OB progenitors deficient in CaMKK2. On the other hand, genetic ablation of CaMKK2 or its pharmacological inhibition in OC progenitors results in reduced pCREB as well as significantly reduced levels of its transcriptional target, nuclear factor of activated T cells c1 (NFATc1). Moreover, in vivo administration of STO-609 results in increased OBs and diminished OCs, conferring significant protection from ovariectomy (OVX)-induced osteoporosis in adult mice. Overall, our findings reveal a novel function for CaMKK2 in bone remodeling and highlight the potential for its therapeutic

  7. Imatinib mesylate inhibits platelet derived growth factor stimulated proliferation of rheumatoid synovial fibroblasts

    SciTech Connect

    Sandler, Charlotta; Joutsiniemi, Saima; Lindstedt, Ken A.; Juutilainen, Timo; Kovanen, Petri T.; Eklund, Kari K. . E-mail: kari.eklund@hus.fi

    2006-08-18

    Synovial fibroblast is the key cell type in the growth of the pathological synovial tissue in arthritis. Here, we show that platelet-derived growth factor (PDGF) is a potent mitogen for synovial fibroblasts isolated from patients with rheumatoid arthritis. Inhibition of PDGF-receptor signalling by imatinib mesylate (1 {mu}M) completely abrogated the PDGF-stimulated proliferation and inhibited approximately 70% of serum-stimulated proliferation of synovial fibroblasts. Similar extent of inhibition was observed when PDGF was neutralized with anti-PDGF antibodies, suggesting that imatinib mesylate does not inhibit pathways other than those mediated by PDGF-receptors. No signs of apoptosis were detected in synovial fibroblasts cultured in the presence of imatinib. These results suggest that imatinib mesylate specifically inhibits PDGF-stimulated proliferation of synovial fibroblasts, and that inhibition of PDGF-receptors could represent a feasible target for novel antirheumatic therapies.

  8. Pudendal but not tibial nerve stimulation inhibits bladder contractions induced by stimulation of pontine micturition center in cats.

    PubMed

    Lyon, Timothy D; Ferroni, Matthew C; Kadow, Brian T; Slater, Richard C; Zhang, Zhaocun; Chang, Victor; Lamm, Vladimir; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2016-02-15

    This study examined the possibility that pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS) inhibits the excitatory pathway from the pontine micturition center (PMC) to the urinary bladder. In decerebrate cats under α-chloralose anesthesia, electrical stimulation of the PMC (40 Hz frequency, 0.2-ms pulse width, 10-25 s duration) using a microelectrode induced bladder contractions >20 cmH2O amplitude when the bladder was filled to 60-70% capacity. PNS or TNS (5 Hz, 0.2 ms) at two and four times the threshold (2T and 4T) to induce anal or toe twitch was applied to inhibit the PMC stimulation-induced bladder contractions. Propranolol, a nonselective β-adrenergic receptor antagonist, was administered intravenously (1 mg/kg i.v.) to determine the role of sympathetic pathways in PNS/TNS inhibition. PNS at both 2T and 4T significantly (P < 0.05) reduced the amplitude and area under the curve of the bladder contractions induced by PMC stimulation, while TNS at 4T facilitated the bladder contractions. Propranolol completely eliminated PNS inhibition and TNS facilitation. This study indicates that PNS, but not TNS, inhibits PMC stimulation-induced bladder contractions via a β-adrenergic mechanism that may occur in the detrusor muscle as a result of reflex activity in lumbar sympathetic nerves. Neither PNS nor TNS activated a central inhibitory pathway with synaptic connections to the sacral parasympathetic neurons that innervate the bladder. Understanding the site of action involved in bladder neuromodulation is important for developing new therapies for bladder disorders. PMID:26676253

  9. Thymoquinone strongly inhibits fMLF-induced neutrophil functions and exhibits anti-inflammatory properties in vivo.

    PubMed

    Boudiaf, Kaouthar; Hurtado-Nedelec, Margarita; Belambri, Sahra Amel; Marie, Jean-Claude; Derradji, Yacine; Benboubetra, Mustapha; El-Benna, Jamel; Dang, Pham My-Chan

    2016-03-15

    Polymorphonuclear neutrophils are key players in host defense against pathogens through the robust production of superoxide anion by the NADPH oxidase and the release of antibacterial proteins from granules. However, inappropriate release of these agents in the extracellular environment induces severe tissue injury, thereby contributing to the physiopathology of acute and chronic inflammatory disorders. Many studies have been carried out to identify molecules capable of inhibiting phagocyte functions, in particular superoxide anion production, for therapeutic purposes. In the present study, we show that thymoquinone (TQ), the major component of the volatile oil from Nigella sativa (black cumin) seeds strongly inhibits fMLF-induced superoxide production and granules exocytosis in neutrophils. The inhibition of superoxide anion was not due to a scavenger effect, as TQ did not inhibit superoxide anion produced by the xanthine/xanthine oxidase system. Interestingly, TQ impaired the phosphorylation on Ser-304 and Ser-328 of p47(PHOX), a cytosolic subunit of the NADPH oxidase. TQ also attenuated specific and azurophilic granule exocytosis in fMLF-stimulated neutrophils as evidenced by decreased cell surface expression of gp91(PHOX) and CD11b, and release of myeloperoxidase. Furthermore, both the PKC and MAPK pathways, which are involved in p47(PHOX) phosphorylation and granules exocytosis, respectively, were inhibited by TQ in fMLF-stimulated neutrophils. Finally, in a model of pleurisy induced by λ-carrageenan in rats, TQ reduced neutrophil accumulation in the pleural space, showing that it not only inhibits PMN functions in vitro, but also exhibits anti-inflammatory properties in vivo. Thus, TQ possesses promising anti-inflammatory therapeutic potential. PMID:26774451

  10. Single laser pulse compression via strongly coupled stimulated Brillouin scattering in plasma

    NASA Astrophysics Data System (ADS)

    Peng, H.; Wu, Z. H.; Zuo, Y. L.; Zhang, Z. M.; Zhou, K. N.; Su, J. Q.

    2016-07-01

    Laser amplification in plasma, including stimulated Raman scattering amplification and strongly coupled stimulated Brillouin scattering (sc-SBS) amplification, is very promising to generate ultrahigh-power and ultrashort laser pulses. But both are quite complex in experiments: at least three different laser pulses must be prepared; temporal delay and spatial overlap of these three pulses are difficult. We propose a single pulse compression scheme based on sc-SBS in plasma. Only one moderately long laser is applied, the front part of which ionizes the gas to produced plasma, and gets reflected by a plasma mirror at the end of the gas channel. The reflected front quickly depletes the remaining part of the laser by sc-SBS in the self-similar regime. The output laser is much stronger and shorter. This scheme is at first considered theoretically, then validated by using 1D PIC simulations.

  11. Facilitation and inhibition in the visual system after photic stimulation.

    NASA Technical Reports Server (NTRS)

    Cavaggioni, A.; Goldstein, M. H., Jr.

    1965-01-01

    Changes in shock-evoked response complex /SERC/ RECORDED from visual cortexes of cats after retinal illumination, noting enhancement of waveform after photic stimulation and role of barbiturate anesthetization

  12. Inhibition of mitogen stimulated growth of human colon cancer cells by interferon.

    PubMed Central

    Hamburger, A. W.; Condon, M. E.; O'Donnell, K.

    1988-01-01

    Recombinant human interferon alpha inhibits growth of a human colon cancer cell line, Colo 205. To explore the mechanisms of IFN induced growth inhibition, quiescent Colo 205 cells were stimulated to proliferate in serum-free media by defined growth factors. Addition of insulin, transferrin and selenium (ITS) stimulated DNA synthesis, as measured by 3H-thymidine incorporation, in a dose-dependent manner. IFN-alpha (at concentrations greater than 100 U ml-1) inhibited ITS stimulated DNA synthesis by 63%. Inhibition of cell cycle traverse was confirmed by flow cytometric analysis. Although IFN inhibited growth of ITS-treated cells, steady state levels of c-myc mRNA remained above levels observed in unstimulated cells. IFN inhibited DNA synthesis only when added prior to mitogen stimulation. IFN, added 6 h after exposure of quiescent cells to ITS, failed to inhibit cell growth. Addition of increasing concentrations of ITS failed to overcome the IFN-induced growth inhibition. These results suggest IFN may inhibit cell growth in part by antagonizing the action of growth factors. Images Figure 4 PMID:3166905

  13. Basic study on the influence of inhibition induced by the magnetic stimulation on the peripheral nerve

    NASA Astrophysics Data System (ADS)

    Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Iramina, Keiji

    2015-05-01

    The purpose of this study is to analyze the inhibition mechanism of magnetic stimulation on motor function. A magnetic stimulator with a flat figure-eight coil was used to stimulate the peripheral nerve of the antebrachium. The intensity of magnetic stimulation was 0.8 T, and the stimulation frequency was 1 Hz. The amplitudes of the motor-evoked potentials (MEPs) at the abductor pollicis brevis muscle and first dorsal interosseous muscle were used to evaluate the effects of magnetic stimulation. The effects of magnetic stimulation were evaluated by analyzing the MEP amplitude before and after magnetic stimulation to the primary motor cortex. The results showed that MEP amplitude after magnetic stimulation compared with before magnetic stimulation decreased. Because there were individual differences in MEP amplitude induced by magnetic stimulation, the MEP amplitude after stimulation was normalized by the amplitude of each participant before stimulation. The MEP amplitude after stimulation decreased by approximately 58% (p < 0.01) on average compared with before stimulation. Previous studies suggested that magnetic stimulation to the primary motor cortex induced an increase or a decrease in MEP amplitude. Furthermore, previous studies have shown that the alteration in MEP amplitude was induced by cortical excitability based on magnetic stimulation. The results of this study showed that MEP amplitude decreased following magnetic stimulation to the peripheral nerve. We suggest that the decrease in MEP amplitude found in this study was obtained via the feedback from a peripheral nerve through an afferent nerve to the brain. This study suggests that peripheral excitement by magnetic stimulation of the peripheral nerve may control the central nervous system via afferent feedback.

  14. Intensity dependent waiting time for strong electron trapping events in speckle stimulated raman scatter

    SciTech Connect

    Rose, Harvey; Daughton, W; Yin, L

    2009-01-01

    The onset of Stimulated Raman scatter from an intense laser speckle is the simplest experimentally realizable laser-plasma-interaction environment. Despite this data and recent 3D particle simulations, the controlling mechanism at the onset of backscatter in the kinetic regime when strong electron trapping in the daughter Langmuir wave is a dominant nonlinearity is not understood. This paper explores the consequences of assuming that onset is controlled by large thermal fluctuations. A super exponential dependence of mean reflectivity on speckle intensity in the onset regime is predicted.

  15. Short-term effect of electrical nerve stimulation on spinal reciprocal inhibition during robot-assisted passive stepping in humans.

    PubMed

    Obata, Hiroki; Ogawa, Tetsuya; Kitamura, Taku; Masugi, Yohei; Takahashi, Miho; Kawashima, Noritaka; Nakazawa, Kimitaka

    2015-09-01

    The purpose of this study was to investigate the effect of electrical stimulation to the common peroneal nerve (CPN) on the spinal reflex and reciprocal inhibition (RI) during robot-assisted passive ground stepping (PGS) in healthy subjects. Five interventions were applied for 30 min in healthy subjects: PGS alone; strong CPN stimulation [50% of the maximal tibialis anterior (TA) M-wave, functional electrical stimulation (FES)] alone; weak CPN stimulation [just above the MT for the TA muscle, therapeutic electrical stimulation (TES)] alone; PGS with FES; and PGS with TES. FES and TES were applied intermittently to the CPN at 25 Hz. The soleus (Sol) H-reflex and RI, which was assessed by conditioning the Sol H-reflex with CPN stimulation, were investigated before (baseline), and 5, 15 and 30 min after each intervention. The amplitudes of the Sol H-reflex were not significantly different after each intervention as compared with the baseline values. The amounts of RI were significantly decreased 5 min after PGS with FES as compared with the baseline values, whereas they were significantly increased 5 and 15 min after PGS with TES. The other interventions did not affect the amount of RI. These results suggest that interventions that combined PGS with CPN stimulation changed the spinal RI in an intensity-dependent manner. PMID:26108136

  16. Venom peptides cathelicidin and lycotoxin cause strong inhibition of Escherichia coli ATP synthase.

    PubMed

    Azim, Sofiya; McDowell, Derek; Cartagena, Alec; Rodriguez, Ricky; Laughlin, Thomas F; Ahmad, Zulfiqar

    2016-06-01

    Venom peptides are known to have strong antimicrobial activity and anticancer properties. King cobra cathelicidin or OH-CATH (KF-34), banded krait cathelicidin (BF-30), wolf spider lycotoxin I (IL-25), and wolf spider lycotoxin II (KE-27) venom peptides were found to strongly inhibit Escherichia coli membrane bound F1Fo ATP synthase. The potent inhibition of wild-type E. coli in comparison to the partial inhibition of null E. coli by KF-34, BF-30, Il-25, or KE-27 clearly links the bactericidal properties of these venom peptides to the binding and inhibition of ATP synthase along with the possibility of other inhibitory targets. The four venom peptides KF-34, BF-30, IL-25, and KE-27, caused ≥85% inhibition of wild-type membrane bound E.coli ATP synthase. Venom peptide induced inhibition of ATP synthase and the strong abrogation of wild-type E. coli cell growth in the presence of venom peptides demonstrates that ATP synthase is a potent membrane bound molecular target for venom peptides. Furthermore, the process of inhibition was found to be fully reversible. PMID:26930579

  17. Strong coupling and stimulated emission in single parabolic quantum well microcavity for terahertz cascade

    SciTech Connect

    Tzimis, A.; Savvidis, P. G.; Trifonov, A. V.; Ignatiev, I. V.; Christmann, G.; Tsintzos, S. I.; Hatzopoulos, Z.; Kavokin, A. V.

    2015-09-07

    We report observation of strong light-matter coupling in an AlGaAs microcavity (MC) with an embedded single parabolic quantum well. The parabolic potential is achieved by varying aluminum concentration along the growth direction providing equally spaced energy levels, as confirmed by Brewster angle reflectivity from a reference sample without MC. It acts as an active region of the structure which potentially allows cascaded emission of terahertz (THz) light. Spectrally and time resolved pump-probe spectroscopy reveals characteristic quantum beats whose frequencies range from 0.9 to 4.5 THz, corresponding to energy separation between relevant excitonic levels. The structure exhibits strong stimulated nonlinear emission with simultaneous transition to weak coupling regime. The present study highlights the potential of such devices for creating cascaded relaxation of bosons, which could be utilized for THz emission.

  18. Charge-balanced biphasic electrical stimulation inhibits neurite extension of spiral ganglion neurons.

    PubMed

    Shen, Na; Liang, Qiong; Liu, Yuehong; Lai, Bin; Li, Wen; Wang, Zhengmin; Li, Shufeng

    2016-06-15

    Intracochlear application of exogenous or transgenic neurotrophins, such as neurotrophin-3 (NT-3) and brain derived neurotrophic factor (BDNF), could promote the resprouting of spiral ganglion neuron (SGN) neurites in deafened animals. These resprouting neurites might reduce the gap between cochlear implant electrodes and their targeting SGNs, allowing for an improvement of spatial resolution of electrical stimulation. This study is to investigate the impact of electrical stimulation employed in CI on the extension of resprouting SGN neurites. We established an in vitro model including the devices delivering charge-balanced biphasic electrical stimulation, and spiral ganglion (SG) dissociated culture treated with BDNF and NT-3. After electrical stimulation with varying durations and intensities, we quantified neurite lengths and Schwann cell densities in SG cultures. Stimulations that were greater than 50μA or longer than 8h significantly decreased SG neurite length. Schwann cell density under 100μA electrical stimulation for 48h was significantly lower compared to that in non-stimulated group. These electrical stimulation-induced decreases of neurite extension and Schwann cell density were attenuated by various types of voltage-dependent calcium channel (VDCC) blockers, or completely prevented by their combination, cadmium or calcium-free medium. Our study suggested that charge-balanced biphasic electrical stimulation inhibited the extension of resprouting SGN neurites and decreased Schwann cell density in vitro. Calcium influx through multiple types of VDCCs was involved in the electrical stimulation-induced inhibition. PMID:27163199

  19. Epidermal growth factor (EGF) inhibits stimulated thyroid hormone secretion in the mouse

    SciTech Connect

    Ahren, B.

    1987-07-01

    It is known that epidermal growth factor (EGF) inhibits iodide uptake in the thyroid follicular cells and lowers plasma levels of thyroid hormones upon infusion into sheep and ewes. In this study, the effects of EGF on basal and stimulated thyroid hormone secretion were investigated in the mouse. Mice were pretreated with /sup 125/I and thyroxine; the subsequent release of /sup 125/I is an estimation of thyroid hormone secretion. It was found that basal radioiodine secretion was not altered by intravenous injection of EGF (5 micrograms/animal). However, the radioiodine secretion stimulated by both TSH (120 microU/animal) and vasoactive intestinal peptide (VIP; 5 micrograms/animal) were inhibited by EGF (5 micrograms/animal). At a lower dose level (0.5 microgram/animal), EGF had no influence on stimulated radioiodine secretion. In conclusion, EGF inhibits stimulated thyroid hormone secretion in the mouse.

  20. Histophilus somni Stimulates Expression of Antiviral Proteins and Inhibits BRSV Replication in Bovine Respiratory Epithelial Cells

    PubMed Central

    Lin, C.; Agnes, J. T.; Behrens, N.; Tagawa, Y.; Gershwin, L. J.; Corbeil, L. B.

    2016-01-01

    Our previous studies showed that bovine respiratory syncytial virus (BRSV) followed by Histophilus somni causes more severe bovine respiratory disease and a more permeable alveolar barrier in vitro than either agent alone. However, microarray analysis revealed the treatment of bovine alveolar type 2 (BAT2) epithelial cells with H. somni concentrated culture supernatant (CCS) stimulated up-regulation of four antiviral protein genes as compared with BRSV infection or dual treatment. This suggested that inhibition of viral infection, rather than synergy, may occur if the bacterial infection occurred before the viral infection. Viperin (or radical S-adenosyl methionine domain containing 2—RSAD2) and ISG15 (IFN-stimulated gene 15—ubiquitin-like modifier) were most up-regulated. CCS dose and time course for up-regulation of viperin protein levels were determined in treated bovine turbinate (BT) upper respiratory cells and BAT2 lower respiratory cells by Western blotting. Treatment of BAT2 cells with H. somni culture supernatant before BRSV infection dramatically reduced viral replication as determined by qRT PCR, supporting the hypothesis that the bacterial infection may inhibit viral infection. Studies of the role of the two known H. somni cytotoxins showed that viperin protein expression was induced by endotoxin (lipooligosaccharide) but not by IbpA, which mediates alveolar permeability and H. somni invasion. A naturally occurring IbpA negative asymptomatic carrier strain of H. somni (129Pt) does not cause BAT2 cell retraction or permeability of alveolar cell monolayers, so lacks virulence in vitro. To investigate initial steps of pathogenesis, we showed that strain 129Pt attached to BT cells and induced a strong viperin response in vitro. Thus colonization of the bovine upper respiratory tract with an asymptomatic carrier strain lacking virulence may decrease viral infection and the subsequent enhancement of bacterial respiratory infection in vivo. PMID:26859677

  1. Histophilus somni Stimulates Expression of Antiviral Proteins and Inhibits BRSV Replication in Bovine Respiratory Epithelial Cells.

    PubMed

    Lin, C; Agnes, J T; Behrens, N; Shao, M; Tagawa, Y; Gershwin, L J; Corbeil, L B

    2016-01-01

    Our previous studies showed that bovine respiratory syncytial virus (BRSV) followed by Histophilus somni causes more severe bovine respiratory disease and a more permeable alveolar barrier in vitro than either agent alone. However, microarray analysis revealed the treatment of bovine alveolar type 2 (BAT2) epithelial cells with H. somni concentrated culture supernatant (CCS) stimulated up-regulation of four antiviral protein genes as compared with BRSV infection or dual treatment. This suggested that inhibition of viral infection, rather than synergy, may occur if the bacterial infection occurred before the viral infection. Viperin (or radical S-adenosyl methionine domain containing 2--RSAD2) and ISG15 (IFN-stimulated gene 15--ubiquitin-like modifier) were most up-regulated. CCS dose and time course for up-regulation of viperin protein levels were determined in treated bovine turbinate (BT) upper respiratory cells and BAT2 lower respiratory cells by Western blotting. Treatment of BAT2 cells with H. somni culture supernatant before BRSV infection dramatically reduced viral replication as determined by qRT PCR, supporting the hypothesis that the bacterial infection may inhibit viral infection. Studies of the role of the two known H. somni cytotoxins showed that viperin protein expression was induced by endotoxin (lipooligosaccharide) but not by IbpA, which mediates alveolar permeability and H. somni invasion. A naturally occurring IbpA negative asymptomatic carrier strain of H. somni (129Pt) does not cause BAT2 cell retraction or permeability of alveolar cell monolayers, so lacks virulence in vitro. To investigate initial steps of pathogenesis, we showed that strain 129Pt attached to BT cells and induced a strong viperin response in vitro. Thus colonization of the bovine upper respiratory tract with an asymptomatic carrier strain lacking virulence may decrease viral infection and the subsequent enhancement of bacterial respiratory infection in vivo. PMID:26859677

  2. Bifunctional bioceramics stimulating osteogenic differentiation of a gingival fibroblast and inhibiting plaque biofilm formation.

    PubMed

    Shen, Ya; Wang, Zhejun; Wang, Jiao; Zhou, Yinghong; Chen, Hui; Wu, Chengtie; Haapasalo, Markus

    2016-04-22

    Gingival recession is a common clinical problem that results in esthetic deficiencies and poor plaque control and predominantly occurs in aged patients. In order to restore the cervical region, ideal biomaterials should possess the ability to stimulate proliferation and osteogenesis/cementogenesis of human gingival fibroblasts (HGF) and have a strong antibiofilm effect. The aim of the present study was to investigate the interactions of HGF and oral multispecies biofilms with Ca, Mg and Si-containing bredigite (BRT, Ca7MgSi4O16) bioceramics. BRT extract induced osteogenic/cementogenic differentiation of HGF and its inhibition of plaque biofilm formation were systematically studied. BRT extract in concentrations lower than <200 mg mL(-1) presented high biocompatibility to HGF cells in 3 days. Ion extracts from BRT also stimulated a series of bone-related gene and protein expressions in HGF cells. Furthermore, BRT extract significantly inhibited oral multispecies plaque biofilm growth on its surface and contributed to over 30% bacterial cell death without additional antibacterial agents in two weeks. A planktonic killing test showed that BRT suppressed 98% plaque bacterial growth compared to blank control in 3 days. The results also revealed that BRT extract has an osteostimulation effect on HGF. The suppression effect on plaque biofilms suggested that BRT might be used as a bioactive material for cervical restoration and that the synergistic effect of bioactive ions, such as Ca, Mg and Si ions, played an important role in the design and construction of bifunctional biomaterials in combination with tissue regeneration and antibiofilm activity. PMID:26806408

  3. Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis.

    PubMed

    Koopman, Frieda A; Chavan, Sangeeta S; Miljko, Sanda; Grazio, Simeon; Sokolovic, Sekib; Schuurman, P Richard; Mehta, Ashesh D; Levine, Yaakov A; Faltys, Michael; Zitnik, Ralph; Tracey, Kevin J; Tak, Paul P

    2016-07-19

    Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the "inflammatory reflex," is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1β, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases. PMID:27382171

  4. Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis

    PubMed Central

    Koopman, Frieda A.; Chavan, Sangeeta S.; Miljko, Sanda; Grazio, Simeon; Sokolovic, Sekib; Schuurman, P. Richard; Mehta, Ashesh D.; Levine, Yaakov A.; Faltys, Michael; Zitnik, Ralph; Tracey, Kevin J.; Tak, Paul P.

    2016-01-01

    Rheumatoid arthritis (RA) is a heterogeneous, prevalent, chronic autoimmune disease characterized by painful swollen joints and significant disabilities. Symptomatic relief can be achieved in up to 50% of patients using biological agents that inhibit tumor necrosis factor (TNF) or other mechanisms of action, but there are no universally effective therapies. Recent advances in basic and preclinical science reveal that reflex neural circuits inhibit the production of cytokines and inflammation in animal models. One well-characterized cytokine-inhibiting mechanism, termed the “inflammatory reflex,” is dependent upon vagus nerve signals that inhibit cytokine production and attenuate experimental arthritis severity in mice and rats. It previously was unknown whether directly stimulating the inflammatory reflex in humans inhibits TNF production. Here we show that an implantable vagus nerve-stimulating device in epilepsy patients inhibits peripheral blood production of TNF, IL-1β, and IL-6. Vagus nerve stimulation (up to four times daily) in RA patients significantly inhibited TNF production for up to 84 d. Moreover, RA disease severity, as measured by standardized clinical composite scores, improved significantly. Together, these results establish that vagus nerve stimulation targeting the inflammatory reflex modulates TNF production and reduces inflammation in humans. These findings suggest that it is possible to use mechanism-based neuromodulating devices in the experimental therapy of RA and possibly other autoimmune and autoinflammatory diseases. PMID:27382171

  5. Phorbol ester stimulates secretory activity while inhibiting receptor-activated aminopyrine uptake by gastric glands

    SciTech Connect

    Brown, M.R.; Chew, C.S.

    1986-03-05

    Both cyclic AMP-dependent and -independent secretagogues stimulate pepsinogen release, respiration and H/sup +/ secretory activity (AP uptake) in rabbit gastric glands. 12-O-tetradecanoylphorbol-13-acetate (T), a diacyglycerol analog, activates protein kinase C (PKC) and stimulates secretion in many systems. T stimulated respiration and pepsinogen release by glands and increased AP uptake by both glands and purified parietal cells. However, T reduced AP uptake by glands stimulated with carbachol (C) or histamine (H) with an apparent IC/sub 50/ of 1 nM. Preincubation with T for 30 min produced maximum inhibition which was not reversed by removal of T. T accelerated the decline of the transient C peak while the late steady state response to H was most inhibited. H-stimulated AP uptake was also inhibited by 50 ..mu..g/ml 1-oleoyl-2-acetyl-glycerol, a reported PKC activator, but not by the inactive phorbol, 4..cap alpha..-phorbol-12,13-didecanoate. In contrast, T potentiated AP uptake by glands stimulated with submaximal doses of dibutyryl cyclic AMP. These results suggest inhibition by T is a specific effect of PKC activators. The differing effects of T on secretion indicators may result from a dual action of T on receptor and post-receptor intracellular events.

  6. The strong anti-glioblastoma capacity of the plasma-stimulated lysine-rich medium

    NASA Astrophysics Data System (ADS)

    Yan, Dayun; Nourmohammadi, Niki; Talbot, Annie; Sherman, Jonathan H.; Keidar, Michael

    2016-07-01

    Plasma-stimulated medium (PSM) shows a remarkable anti-cancer capacity as strong as the direct cold atmospheric plasma (CAP) treatment of cancer cells. PSM is able to effectively resist the growth of several cancer cell lines. To date, the sole approach to strengthen the anti-cancer capacity of PSM is extending the plasma treatment time. In this study, we demonstrated that the anti-glioblastoma capacity of PSM could be significantly increased by adding 20 mM lysine in Dulbecco’s modified Eagle’s medium (DMEM). This study provides clear evidence that the anti-glioblastoma capacity of PSM could be noticeably enhanced by modifying the composition of medium without increasing the CAP treatment time.

  7. Vanadate Inhibits Blue Light-Stimulated Swelling of Vicia Guard Cell Protoplasts 1

    PubMed Central

    Amodeo, Gabriela; Srivastava, Alaka; Zeiger, Eduardo

    1992-01-01

    When supplied under low chloride concentrations, vanadate inhibits the blue light-stimulated swelling of Vicia faba L. guard cell protoplasts in a dose-dependent fashion. The volume of guard cell protoplasts incubated in 10 mm K-imino-diacetic acid, 0.4 m mannitol, and 1 mm CaCl2 remained essentially constant under 1000 μmol m−2 s−1 red light, but increased an average of 27% after 8 min of the addition of 50 μmol m−2 s−1 blue light to the background red light. At 500 μm, vanadate completely inhibits the response to blue light. Vanadate also inhibits the swelling of guard cell protoplasts stimulated by the H+-ATPase agonist fusicoccin. The vanadate sensitivity of the blue light-stimulated swelling implicates a proton-pumping ATPase as a component of the sensory transduction of blue light in guard cells. Images Figure 3 PMID:16653159

  8. Strong Static Magnetic Fields Elicit Swimming Behaviors Consistent with Direct Vestibular Stimulation in Adult Zebrafish

    PubMed Central

    Ward, Bryan K.; Tan, Grace X-J; Roberts, Dale C.; Della Santina, Charles C.; Zee, David S.; Carey, John P.

    2014-01-01

    Zebrafish (Danio rerio) offer advantages as model animals for studies of inner ear development, genetics and ototoxicity. However, traditional assessment of vestibular function in this species using the vestibulo-ocular reflex requires agar-immobilization of individual fish and specialized video, which are difficult and labor-intensive. We report that using a static magnetic field to directly stimulate the zebrafish labyrinth results in an efficient, quantitative behavioral assay in free-swimming fish. We recently observed that humans have sustained nystagmus in high strength magnetic fields, and we attributed this observation to magnetohydrodynamic forces acting on the labyrinths. Here, fish were individually introduced into the center of a vertical 11.7T magnetic field bore for 2-minute intervals, and their movements were tracked. To assess for heading preference relative to a magnetic field, fish were also placed in a horizontally oriented 4.7T magnet in infrared (IR) light. A sub-population was tested again in the magnet after gentamicin bath to ablate lateral line hair cell function. Free-swimming adult zebrafish exhibited markedly altered swimming behavior while in strong static magnetic fields, independent of vision or lateral line function. Two-thirds of fish showed increased swimming velocity or consistent looping/rolling behavior throughout exposure to a strong, vertically oriented magnetic field. Fish also demonstrated altered swimming behavior in a strong horizontally oriented field, demonstrating in most cases preferred swimming direction with respect to the field. These findings could be adapted for ‘high-throughput’ investigations of the effects of environmental manipulations as well as for changes that occur during development on vestibular function in zebrafish. PMID:24647586

  9. Strong static magnetic fields elicit swimming behaviors consistent with direct vestibular stimulation in adult zebrafish.

    PubMed

    Ward, Bryan K; Tan, Grace X-J; Roberts, Dale C; Della Santina, Charles C; Zee, David S; Carey, John P

    2014-01-01

    Zebrafish (Danio rerio) offer advantages as model animals for studies of inner ear development, genetics and ototoxicity. However, traditional assessment of vestibular function in this species using the vestibulo-ocular reflex requires agar-immobilization of individual fish and specialized video, which are difficult and labor-intensive. We report that using a static magnetic field to directly stimulate the zebrafish labyrinth results in an efficient, quantitative behavioral assay in free-swimming fish. We recently observed that humans have sustained nystagmus in high strength magnetic fields, and we attributed this observation to magnetohydrodynamic forces acting on the labyrinths. Here, fish were individually introduced into the center of a vertical 11.7T magnetic field bore for 2-minute intervals, and their movements were tracked. To assess for heading preference relative to a magnetic field, fish were also placed in a horizontally oriented 4.7T magnet in infrared (IR) light. A sub-population was tested again in the magnet after gentamicin bath to ablate lateral line hair cell function. Free-swimming adult zebrafish exhibited markedly altered swimming behavior while in strong static magnetic fields, independent of vision or lateral line function. Two-thirds of fish showed increased swimming velocity or consistent looping/rolling behavior throughout exposure to a strong, vertically oriented magnetic field. Fish also demonstrated altered swimming behavior in a strong horizontally oriented field, demonstrating in most cases preferred swimming direction with respect to the field. These findings could be adapted for 'high-throughput' investigations of the effects of environmental manipulations as well as for changes that occur during development on vestibular function in zebrafish. PMID:24647586

  10. Alpha-melanocyte stimulating hormone inhibits monocytes adhesion to vascular endothelium.

    PubMed

    Yang, Yang; Zhang, Weihua; Meng, Lin; Yu, Haitao; Lu, Na; Fu, Gang; Zheng, Yang

    2015-11-01

    Inflammation and its subsequent endothelial dysfunction have been reported to play a pivotal role in the initiation and progression of chronic vascular diseases. Inhibiting the attachment of monocytes to endothelium is a potential therapeutic strategy for vascular diseases treatment. α-Melanocyte stimulating hormone is generated from a precursor hormone called proopiomelanocortin by post-translational processing. However, whether α-melanocyte stimulating hormone plays a role in regulating endothelial inflammation is still unknown. In this study, the effects of α-melanocyte stimulating hormone on endothelial inflammation in human umbilical vein endothelial cell lines were investigated. And the result indicated that α-melanocyte stimulating hormone inhibits the expression of endothelial adhesion molecules, including vascular adhesion molecule-1 and E-selectin, thereby attenuating the adhesion of THP-1 cells to the surface of endothelial cells. Mechanistically, α-melanocyte stimulating hormone was found to inhibit NF-κB transcriptional activity. Finally, we found that the effect of α-melanocyte stimulating hormone on endothelial inflammation is dependent on its receptor melanocortin receptor 1. PMID:25898835

  11. Inhibition of DNA fragmentation in thymocytes and isolated thymocyte nuclei by agents that stimulate protein kinase C.

    PubMed

    McConkey, D J; Hartzell, P; Jondal, M; Orrenius, S

    1989-08-15

    Glucocorticoid hormones and Ca2+ ionophores stimulate a suicide process in immature thymocytes, known as apoptosis or programmed cell death, that involves extensive DNA fragmentation. We have recently shown that a sustained increase in cytosolic Ca2+ concentration stimulates DNA fragmentation and cell killing in glucocorticoid- or ionophore-treated thymocytes. However, a sustained increase in the cytosolic Ca2+ level also mediates lymphocyte proliferation, suggesting that apoptosis is blocked in proliferating thymocytes. In this study we report that phorbol esters, which selectively stimulate protein kinase C (PKC), blocked DNA fragmentation and cell death in thymocytes exposed to Ca2+ ionophore or glucocorticoid hormone. The T cell mitogen, concanavalin A, which stimulates thymocytes by a mechanism that involves PKC activation, caused concentration-dependent increases in the cytosolic Ca2+ level that did not result in DNA fragmentation, but incubation with concanavalin A and the PKC inhibitor H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine) resulted in both DNA fragmentation and cell death. Phorbol ester directly inhibited Ca2+-dependent DNA fragmentation in isolated thymocyte nuclei. Our results strongly suggest that PKC activation blocks thymocyte apoptosis by preventing Ca2+-stimulated endonuclease activation. PMID:2503500

  12. Thienoquinolins exert diuresis by strongly inhibiting UT-A urea transporters.

    PubMed

    Ren, Huiwen; Wang, Yanhua; Xing, Yongning; Ran, Jianhua; Liu, Ming; Lei, Tianluo; Zhou, Hong; Li, Runtao; Sands, Jeff M; Yang, Baoxue

    2014-12-15

    Urea transporters (UT) play an important role in the urine concentration mechanism by mediating intrarenal urea recycling, suggesting that UT inhibitors could have therapeutic use as a novel class of diuretic. Recently, we found a thienoquinolin UT inhibitor, PU-14, that exhibited diuretic activity. The purpose of this study was to identify more potent UT inhibitors that strongly inhibit UT-A isoforms in the inner medullary collecting duct (IMCD). Efficient thienoquinolin UT inhibitors were identified by structure-activity relationship analysis. Urea transport inhibition activity was assayed in perfused rat terminal IMCDs. Diuretic activity of the compound was determined in rats and mice using metabolic cages. The results show that the compound PU-48 exhibited potent UT-A inhibition activity. The inhibition was 69.5% with an IC50 of 0.32 μM. PU-48 significantly inhibited urea transport in perfused rat terminal IMCDs. PU-48 caused significant diuresis in UT-B null mice, which indicates that UT-A is the target of PU-48. The diuresis caused by PU-48 did not change blood Na(+), K(+), or Cl(-) levels or nonurea solute excretion in rats and mice. No toxicity was detected in cells or animals treated with PU-48. The results indicate that thienoquinolin UT inhibitors induce a diuresis by inhibiting UT-A in the IMCD. This suggests that they may have the potential to be developed as a novel class of diuretics with fewer side effects than classical diuretics. PMID:25298523

  13. Thienoquinolins exert diuresis by strongly inhibiting UT-A urea transporters

    PubMed Central

    Ren, Huiwen; Wang, Yanhua; Xing, Yongning; Ran, Jianhua; Liu, Ming; Lei, Tianluo; Zhou, Hong; Li, Runtao; Sands, Jeff M.

    2014-01-01

    Urea transporters (UT) play an important role in the urine concentration mechanism by mediating intrarenal urea recycling, suggesting that UT inhibitors could have therapeutic use as a novel class of diuretic. Recently, we found a thienoquinolin UT inhibitor, PU-14, that exhibited diuretic activity. The purpose of this study was to identify more potent UT inhibitors that strongly inhibit UT-A isoforms in the inner medullary collecting duct (IMCD). Efficient thienoquinolin UT inhibitors were identified by structure-activity relationship analysis. Urea transport inhibition activity was assayed in perfused rat terminal IMCDs. Diuretic activity of the compound was determined in rats and mice using metabolic cages. The results show that the compound PU-48 exhibited potent UT-A inhibition activity. The inhibition was 69.5% with an IC50 of 0.32 μM. PU-48 significantly inhibited urea transport in perfused rat terminal IMCDs. PU-48 caused significant diuresis in UT-B null mice, which indicates that UT-A is the target of PU-48. The diuresis caused by PU-48 did not change blood Na+, K+, or Cl− levels or nonurea solute excretion in rats and mice. No toxicity was detected in cells or animals treated with PU-48. The results indicate that thienoquinolin UT inhibitors induce a diuresis by inhibiting UT-A in the IMCD. This suggests that they may have the potential to be developed as a novel class of diuretics with fewer side effects than classical diuretics. PMID:25298523

  14. Inhibition of hormone-stimulated lipolysis by clofibrate. A possible mechanism for its hypolipidemic action.

    PubMed Central

    D'Costa, M A; Angel, A

    1975-01-01

    The present study was undertaken to investigate the mechanism of the antilipolytic action of clofibrate (p-chlorophenoxyisobutyrate). Clofibrate, in the dose range of 10-80 mg/199 ml, inhibited the initial rate of norepinephrine-stimulated lipolysis 17-44 percent in isolated rat fat cells. At a dose corresponding to therapeutic levels in vivo (10 mg/100 ml) clofibrate also inhibited hormone-stimulated lipolysis by 20-30 percent in fragments of human subcutaneous fat. Inhibition of lipolysis by clofibrate occurred at all concentrations of norepinephrine and ACTH (0.02-0.1 mug/ml) but did not occur with equilipolytic concentrations of dibutyryl cyclic AMP, suggesting a proximal site of action on the lipolytic sequence. Clofibrate reduced by 60 percent (315plus or minus40 vs. 120plus or minus25 pmol/g lipid; meanplus or minusSEM) the norepinephrine-stimulated initial rise in cyclic AMP, measured 10 min after addition of hormone. Because the antilipolytic effect occurred in the presence of glucose and without altering cellular ATP levels, the reduction in intracellular cyclic AMP levels could not be attributed to uncoupling of oxidative metabolism or to secondary effects of free fatty acid accumulation. In the secondary effects of free fatty acid accumulation. In the presence of procaine-HC1, which blocks hormone-stimulated lipolysis without inhibiting cyclic AMP accumulation, addition of clofibrate prevented the hormone-stimulated rise in cyclic AMP. Clofibrate did not affect the activity of the low-Km 3',5'-cyclic AMP phosphodiesterase in norepinephrine-stimulated adipocytes. These data suggest that the antilipolytic effect of clofibrate is due to its suppression of cyclic AMP production by inhibition of adenylate cyclase. The drug's hypolipidemic action may in part be explained by its antilipolytic effect, which deprives the liver of free fatty acid substrate for lipoprotein synthesis. Images PMID:162783

  15. Arbidol exhibits strong inhibition towards UDP-glucuronosyltransferase (UGT) 1A9 and 2B7.

    PubMed

    Liu, Xin; Huang, Ting; Chen, Jian-Xing; Zeng, Jia; Fan, Xu-Ran; Xu-Zhu; Yu, Zhen-Wen; Sun, Xiao-Yu; Hong, Mo; Sun, Hong-Zhi

    2013-12-01

    The aim of the present study was to investigate arbidol's inhibition towards UDP-glucuronosyltransferase (UGT) 1A9 and 2B7. The nonspecific probe substrate 4-methylumbelliferone (4-MU) and recombinant UGT enzymes (UGT1A9, UGT2B7) were firstly used to evaluate the inhibition of arbidol towards UGT1A9 and UGT2B7. Furthermore, specific substrates of UGT1A9 and UGT2B7 propofol and zidovudine (AZT) were used to determine the inhibition of arbidol towards UGT1A9 and UGT2B7. Inhibition type and inhibition kinetic parameters (Ki) were determined. In vitro-in vivo extrapolation (IV-IVE) was performed to predict in vivo DDI magnitude induced by arbidol. Arbidol was demonstrated to exhibit competitive inhibition towards UGT1A9 and UGT2B7 without substate-dependent behaviour. The inhibition kinetic parameters (Ki) were calculated to be 0.5 microM, 3.5 microM, 2.8 microM, 29.7 microM for UGT2B7-mediated 4-MU glucuronidation, UGT1A9-mediated 4-MU glucuronidation, UGT2B7-mediated AZT glucuronidation, and UGT1A9-mediated propofol glucuronidation, respectively. Using these parameters, the in vivo alteration of area under of concentration-time curve (AUC) was calculated to be 156%, 22%, 28% and 2.6%, respectively. Given that arbidol exhibits strong inhibition towards UGT1A9 and UGT2B7, clinical monitoring should be given when arbidol was co-administered with drugs mainly undergoing UGT1A9, UGT2B7-mediated metabolism. PMID:24400440

  16. Complete inhibition of food-stimulated gastric acid secretion by combined application of pirenzepine and ranitidine.

    PubMed

    Londong, W; Londong, V; Ruthe, C; Weizert, P

    1981-07-01

    In a double-blind, placebo controlled and randomised secretory study the effectiveness of pirenzepine, ranitidine, and their combination was compared intraindividually in eight healthy subjects receiving intravenous bolus injections. Pirenzepine (0.15 mg/kg) plus ranitidine (0.6 mg/kg) suppressed peptone-stimulated gastric acid secretion from 69 +/- 11 to 2 +/- 0.4 mmol H+/3 h; the mean percentage inhibition was 97%. Postprandial gastrin was unaffected. There were only minor side-effects in a few experiments (reduction of salivation, brief blurring of vision), but no prolactin stimulation after ranitidine or ranitidine plus pirenzepine. The combined application of ranitidine and pirenzepine inhibited meal-stimulated acid secretion more effectively and produced fewer side-effects than the combination of cimetidine plus pirenzepine studied previously. PMID:6114900

  17. CD95 co-stimulation blocks activation of naive T cells by inhibiting T cell receptor signaling

    PubMed Central

    Lindquist, Jonathan A.; Arhel, Nathalie; Felder, Edward; Karl, Sabine; Haas, Tobias L.; Fulda, Simone; Walczak, Henning; Kirchhoff, Frank; Debatin, Klaus-Michael

    2009-01-01

    CD95 is a multifunctional receptor that induces cell death or proliferation depending on the signal, cell type, and cellular context. Here, we describe a thus far unknown function of CD95 as a silencer of T cell activation. Naive human T cells triggered by antigen-presenting cells expressing a membrane-bound form of CD95 ligand (CD95L) or stimulated by anti-CD3 and -CD28 antibodies in the presence of recombinant CD95L had reduced activation and proliferation, whereas preactivated, CD95-sensitive T cells underwent apoptosis. Triggering of CD95 during T cell priming interfered with proximal T cell receptor signaling by inhibiting the recruitment of ζ-chain–associated protein of 70 kD, phospholipase-γ, and protein kinase C-θ into lipid rafts, thereby preventing their mutual tyrosine protein phosphorylation. Subsequently, Ca2+ mobilization and nuclear translocation of transcription factors NFAT, AP1, and NF-κB were strongly reduced, leading to impaired cytokine secretion. CD95-mediated inhibition of proliferation in naive T cells could not be reverted by the addition of exogenous interleukin-2 and T cells primed by CD95 co-stimulation remained partially unresponsive upon secondary T cell stimulation. HIV infection induced CD95L expression in primary human antigeen-presenting cells, and thereby suppressed T cell activation, suggesting that CD95/CD95L-mediated silencing of T cell activation represents a novel mechanism of immune evasion. PMID:19487421

  18. Deep Brain Stimulation: More Complex than the Inhibition of Cells and Excitation of Fibers.

    PubMed

    Florence, Gerson; Sameshima, Koichi; Fonoff, Erich T; Hamani, Clement

    2016-08-01

    High-frequency deep brain stimulation (DBS) is an effective treatment for some movement disorders. Though mechanisms underlying DBS are still unclear, commonly accepted theories include a "functional inhibition" of neuronal cell bodies and the excitation of axonal projections near the electrodes. It is becoming clear, however, that the paradoxical dissociation "local inhibition" and "distant excitation" is far more complex than initially thought. Despite an initial increase in neuronal activity following stimulation, cells are often unable to maintain normal ionic concentrations, particularly those of sodium and potassium. Based on currently available evidence, we proposed an alternative hypothesis. Increased extracellular concentrations of potassium during DBS may change the dynamics of both cells and axons, contributing not only to the intermittent excitation and inhibition of these elements but also to interrupt abnormal pathological activity. In this article, we review mechanisms through which high extracellular potassium may mediate some of the effects of DBS. PMID:26150316

  19. Dual Effect of Chrysanthemum indicum Extract to Stimulate Osteoblast Differentiation and Inhibit Osteoclast Formation and Resorption In Vitro

    PubMed Central

    Baek, Jong Min; Cheon, Yoon-Hee; Park, Sun-Hyang; Ahn, Sung-Jun; Yoon, Kwon-Ha; Oh, Jaemin; Lee, Myeung Su

    2014-01-01

    The risk of bone-related diseases increases due to the imbalance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively. The goal in the development of antiosteoporotic treatments is an agent that will improve bone through simultaneous osteoblast stimulation and osteoclast inhibition without undesirable side effects. To achieve this goal, numerous studies have been performed to identify novel approaches using natural oriental herbs to treat bone metabolic diseases. In the present study, we investigated the effect of Chrysanthemum indicum extract (CIE) on the differentiation of osteoclastic and osteoblastic cells. CIE inhibited the formation of TRAP-positive mature osteoclasts and of filamentous-actin rings and disrupted the bone-resorbing activity of mature osteoclasts in a dose-dependent manner. CIE strongly inhibited Akt, GSK3β, and IκB phosphorylation in RANKL-stimulated bone marrow macrophages and did not show any effects on MAP kinases, including p38, ERK, and JNK. Interestingly, CIE also enhanced primary osteoblast differentiation via upregulation of the expression of alkaline phosphatase and the level of extracellular calcium concentrations during the early and terminal stages of differentiation, respectively. Our results revealed that CIE could have a potential therapeutic role in bone-related disorders through its dual effects on osteoclast and osteoblast differentiation. PMID:25530776

  20. The relief of microtherm inhibition for p-fluoronitrobenzene mineralization using electrical stimulation at low temperatures.

    PubMed

    Zhang, Xueqin; Feng, Huajun; Liang, Yuxiang; Zhao, Zhiqing; Long, Yuyang; Fang, Yuan; Wang, Meizhen; Yin, Jun; Shen, Dongsheng

    2015-05-01

    Low temperature aggravates biological treatment of refractory p-fluoronitrobenzene (p-FNB) because of microtherm inhibition of microbial activity. Considering the potential characterization of energy supply for microbial metabolism and spurring microbial activity by electrical stimulation, a bioelectrochemical system (BES) was established to provide sustaining electrical stimulation for p-FNB mineralization at a low temperature. Electrical stimulation facilitated p-FNB treatment and bioelectrochemical reaction rate constants for the removal and defluorination of p-FNB at 10 °C were 0.0931 and 0.0054 h(-1), which were higher than the sums of the rates found using a biological system and an electrocatalytic system by 62.8 and 64.8%, respectively. At a low temperature, microbial activity in terms of dehydrogenase and ATPase was found to be higher with electrical stimulation, being 121.1 and 100.1% more active than that in the biological system. Moreover, stronger antioxidant ability was observed in the BES, which implied a better cold-resistance and relief of microtherm inhibition by electrical stimulation. Bacterial diversity analysis revealed a significant evolution of microbial community by electrical stimulation, and Clostridia was uniquely enriched. One bacterial sequence close to Pseudomonas became uniquely predominant, which appeared to be crucial for excellent p-FNB treatment performance in the BES at a low temperature. Economic evaluation revealed that the energy required to mineralize an extra mole of p-FNB was found to be 247 times higher by heating the system than by application of electrical stimulation. These results indicated that application of electrical stimulation is extremely promising for treating refractory waste at low temperatures. PMID:25575889

  1. Dopamine Regulation of Lateral Inhibition between Striatal Neurons Gates the Stimulant Actions of Cocaine.

    PubMed

    Dobbs, Lauren K; Kaplan, Alanna R; Lemos, Julia C; Matsui, Aya; Rubinstein, Marcelo; Alvarez, Veronica A

    2016-06-01

    Striatal medium spiny neurons (MSNs) form inhibitory synapses on neighboring striatal neurons through axon collaterals. The functional relevance of this lateral inhibition and its regulation by dopamine remains elusive. We show that synchronized stimulation of collateral transmission from multiple indirect-pathway MSNs (iMSNs) potently inhibits action potentials in direct-pathway MSNs (dMSNs) in the nucleus accumbens. Dopamine D2 receptors (D2Rs) suppress lateral inhibition from iMSNs to disinhibit dMSNs, which are known to facilitate locomotion. Surprisingly, D2R inhibition of synaptic transmission was larger at axon collaterals from iMSNs than their projections to the ventral pallidum. Targeted deletion of D2Rs from iMSNs impaired cocaine's ability to suppress lateral inhibition and increase locomotion. These impairments were rescued by chemogenetic activation of Gi-signaling in iMSNs. These findings shed light on the functional significance of lateral inhibition between MSNs and offer a novel synaptic mechanism by which dopamine gates locomotion and cocaine exerts its canonical stimulant response. VIDEO ABSTRACT. PMID:27181061

  2. Dose-dependent platelet stimulation and inhibition induced by anti-PIA1 IgG

    SciTech Connect

    Ryu, T.; Davis, J.M.; Schwartz, K.A. )

    1990-07-01

    The PIA1 antibody produces several clinically distinct and severe thrombocytopenias. Investigations have demonstrated divergent effects on platelet function; prior reports demonstrated inhibition, while a conflicting publication showed platelet activation. We have resolved this conflict using anti-PIA1 IgG produced by a patient with posttransfusion purpura. Relatively low concentrations stimulated platelet aggregation and release of adenosine triphosphate (ATP) whereas high concentrations inhibited platelet function, producing a thrombasthenia-like state. The number of molecules of platelet-associated IgG necessary to initiate aggregation and ATP release (2,086 +/- 556) or produce maximum aggregation (23,420 +/- 3,706) or complete inhibition (63,582 +/- 2654) were measured with a quantitative radiometric assay for bound anti-PIA1. Preincubation of platelets with high concentrations of PIA1 antibody inhibited platelet aggregation with 10 mumol/L adenosine diphosphate and blocked 125I-labeled fibrinogen platelet binding. Platelet activation with nonfibrinogen dependent agonist, 1 U/ml thrombin, was not inhibited by this high concentration of PIA1 IgG. In conclusion, anti-PIAI IgG produces (1) stimulation of platelet aggregation and ATP release that is initiated with 2000 molecules IgG per platelet and is associated with an increase of 125I-fibrinogen binding; (2) conversely, inhibition of platelet aggregation is observed with maximum antibody binding, 63,000 molecules IgG per platelet, and is mediated via a blockade of fibrinogen binding.

  3. Inhibition of Histone Deacetylases Preserves Myocardial Performance and Prevents Cardiac Remodeling through Stimulation of Endogenous Angiomyogenesis

    PubMed Central

    Zhang, Ling; Qin, Xin; Zhao, Yu; Fast, Loren; Zhuang, Shougang; Liu, Paul; Cheng, Guangmao

    2012-01-01

    We have previously shown that the inhibition of histone deacetylases (HDACs) protects the heart against acute myocardial ischemia and reperfusion injury. We also demonstrated that HDAC inhibition stimulates myogenesis and angiogenesis in a cultured embryonic stem cell model. We investigate whether in vivo inhibition of HDAC preserves cardiac performance and prevents cardiac remodeling in mouse myocardial infarction (MI) through the stimulation of endogenous regeneration. MI was created by ligation of the left descending artery. Animals were divided into three groups: 1) sham group, animals that underwent thoracotomy without MI; 2) MI, animals that underwent MI; and 3) MI + trichostatin A (TSA), MI animals that received a daily intraperitoneal injection of TSA. In addition, infarcted mice received a daily intraperitoneal injection of TSA (0.1 mg/kg), a selective HDAC inhibitor. 5-Bromo-2-deoxyuridine (50 mg/kg) was delivered every other day to pulse-chase label in vivo endogenous cardiac replication. Eight weeks later, the MI hearts showed a reduction in ventricular contractility. HDAC inhibition increased the improvement of myocardial functional recovery after MI, which was associated with the prevention of myocardial remodeling and reduction of myocardial and serum tumor necrosis factor α. HDAC inhibition enhanced the formation of new myocytes and microvessels, which was consistent with the robust increase in proliferation and cytokinesis in the MI hearts. An increase in angiogenic response was demonstrated in MI hearts receiving TSA treatment. It is noteworthy that TSA treatment significantly inhibited HDAC activity and increased phosphorylation of Akt-1, but decreased active caspase 3. Taken together, our results indicate that HDAC inhibition preserves cardiac performance and mitigates myocardial remodeling through stimulating cardiac endogenous regeneration. PMID:22271820

  4. Stimulation of H+ Efflux and Inhibition of Photosynthesis by Esters of Carboxylic Acids 1

    PubMed Central

    Duhaime, Donna E.; Bown, Alan W.

    1983-01-01

    Suspensions of mechanically isolated Asparagus sprengeri Regel mesophyll cells were used to investigate the influence of various carboxyester compounds on rates of net H+ efflux in the dark or light and photosynthetic O2 production. Addition of 0.15 to 1.5 millimolar malathion, α-naphthyl acetate, phenyl acetate, or p-nitrophenyl acetate stimulated H+ efflux and inhibited photosynthesis within 1 minute. In contrast, the more polar esters methyl acetoacetate or ethyl p-aminobenzoate had little or no effect on either of these two processes. A 0.15 millimolar concentration of α-naphthylacetate stimulated the normal rate of H+ efflux, 0.77 nanomoles H+ per 106 cells per minute by 750% and inhibited photosynthesis by 100%. The four active carboxyester compounds also stimulated H+ efflux after the normal rate of H+ efflux was eliminated with 0.01 milligrams per milliliter oligomycin or 100% N2. Oligomycin reduced the ATP level by 70%. Incubation of cells with malathion, α-naphthyl acetate, or p-nitrophenyl acetate resulted in the generation of the respective hydrolysis products ethanol, α-naphthol, and p-nitrophenol. It is proposed that inhibition of photosynthesis and stimulation of H+ efflux result when nonpolar carboxyester compounds enter the cell and generate acidic carboxyl groups when hydrolyzed by esterase enzymes. PMID:16663308

  5. Reinforcement and Stimulant Medication Ameliorate Deficient Response Inhibition in Children with Attention-Deficit/Hyperactivity Disorder.

    PubMed

    Rosch, Keri S; Fosco, Whitney D; Pelham, William E; Waxmonsky, James G; Bubnik, Michelle G; Hawk, Larry W

    2016-02-01

    This study examined the degree to which reinforcement, stimulant medication, and their combination impact response inhibition in children with Attention-Deficit/Hyperactivity Disorder (ADHD). Across three studies, participants with ADHD (n = 111, 25 girls) and typically-developing (TD) controls (n = 33, 6 girls) completed a standard version of the stop signal task (SST) and/or a reinforcement-manipulation SST with performance-contingent points. In two of these studies, these tasks were performed under placebo or 0.3 and 0.6 mg/kg methylphenidate (MPH) conditions. Cross-study comparisons were conducted to test hypotheses regarding the separate and combined effects of reinforcement and methylphenidate on response inhibition among children with ADHD relative to TD controls. Baseline response inhibition was worse among children with ADHD compared to controls. MPH produced dose-related improvements in response inhibition in children with ADHD; compared to non-medicated TD controls, 0.3 mg/kg MPH normalized deficient response inhibition, and 0.6 mg/kg MPH resulted in better inhibition in children with ADHD. Reinforcement improved response inhibition to a greater extent for children with ADHD than for TD children, normalizing response inhibition. The combination of MPH and reinforcement improved response inhibition among children with ADHD compared to reinforcement alone and MPH alone, also resulting in normalization of response inhibition despite repeated task exposure. Deficient response inhibition commonly observed in children with ADHD is significantly improved with MPH and/or reinforcement, normalizing inhibition relative to TD children tested under standard conditions. PMID:25985978

  6. Infrared neural stimulation (INS) inhibits electrically evoked neural responses in the deaf white cat

    NASA Astrophysics Data System (ADS)

    Richter, Claus-Peter; Rajguru, Suhrud M.; Robinson, Alan; Young, Hunter K.

    2014-03-01

    Infrared neural stimulation (INS) has been used in the past to evoke neural activity from hearing and partially deaf animals. All the responses were excitatory. In Aplysia californica, Duke and coworkers demonstrated that INS also inhibits neural responses [1], which similar observations were made in the vestibular system [2, 3]. In deaf white cats that have cochleae with largely reduced spiral ganglion neuron counts and a significant degeneration of the organ of Corti, no cochlear compound action potentials could be observed during INS alone. However, the combined electrical and optical stimulation demonstrated inhibitory responses during irradiation with infrared light.

  7. β3-adrenoceptors inhibit stimulated norepinephrine release in spontaneously hypertensive rats

    PubMed Central

    Berg, Torill

    2014-01-01

    Here, the influence of β3-adrenoceptors on catecholamine release in normotensive and spontaneously hypertensive rats was analyzed. Blood pressure was recorded through a femoral artery catheter, and cardiac output by ascending aorta flow. Time from onset of flow to maximum rise in flow indicated inotropy. Total peripheral vascular resistance (TPR) was calculated. Norepinephrine release was stimulated with tyramine, which allowed presynaptic release-control to be reflected as changes in the plasma norepinephrine concentration. β3-adrenoceptor agonist (BRL37344) reduced baseline vascular resistance, the tyramine-stimulated norepinephrine overflow and the positive inotropic response to tyramine in hypertensive but not normotensive rats. β3-adrenoceptor antagonist (SR59230A) reduced tyramine-stimulated norepinephrine release in both strains and the secretion of epinephrine in hypertensive rats. SR59230A reduced tyramine-induced tachycardia in normotensive rats, and prevented down-regulation of the tyramine-induced rise in resistance in hypertensive rats. It was concluded that the contradicting results obtained by agonist vs. antagonist, could be explained by their interaction with two different β-adrenoceptors: The BRL37344-dependent inhibition of stimulated norepinephrine release and positive inotropic response to tyramine was compatible with stimulation of β3-adrenoceptor coupling to inhibitory G-protein. This was observed only in hypertensive rats during stimulated, high levels of circulating catecholamines. The effect of BRL37344 on baseline vascular resistance was compatible with activation of β3-adrenoceptor coupling to endothelial nitric oxide synthase. The inhibitory effect of SR59230A on tyramine-stimulated norepinephrine release in both strains, the increased TPR-response to tyramine in hypertensive rats and tachycardia in normotensive rats may result from inhibition of the low-affinity-state β1-adrenoceptor, also known as the putative β4-adrenoceptor

  8. Inhibiting and stimulating effects of TGF-. beta. 1 on osteoclastic bone resorption in fetal mouse bone organ cultures

    SciTech Connect

    Dieudonne, S.C.; Foo, P.; van Zoelen, E.J.; Burger, E.H. )

    1991-05-01

    The effects of TGF-{beta} 1 on osteoclastic resorption of fetal mouse calvaria and long bones at various stages of development was studied in organ culture. In resorbing calvariae and long bones with an established marrow cavity TGF-beta 1 (4-10 ng/ml) had a stimulating effect on 45Ca release that was partially inhibited by indomethacin. In primitive long bones, however, which were explanted before osteoclast invasion and excavation of a marrow cavity had started, TGF-beta 1 (1-4 ng/ml) inhibited 45Ca release by an indomethacin-insensitive mechanism. Histomorphometry of long bones after staining for tartrate-resistant acid phosphatase (TRAP) revealed that TGF-beta 1 treatment inhibited the migration of TRAP-positive cells from periosteum to developing marrow cavity and inhibited cell fusion. However, the formation of (mononuclear) TRAP-positive cells in the periosteum-perichondrium was strongly enhanced. These data suggest that TGF-beta 1 modulates various steps in the cascade of osteoclast development, recruitment, and activation in different ways, involving both prostaglandin-mediated and prostaglandin-independent pathways. Therefore the net effect of exogenous TGF-beta 1 on osteoclastic resorption in bone organ cultures depends on the relative prevalence of osteoclast progenitors, precursors, and mature osteoclasts in the tissue under study.

  9. Inhibition of DYRK1A Stimulates Human β-Cell Proliferation.

    PubMed

    Dirice, Ercument; Walpita, Deepika; Vetere, Amedeo; Meier, Bennett C; Kahraman, Sevim; Hu, Jiang; Dančík, Vlado; Burns, Sean M; Gilbert, Tamara J; Olson, David E; Clemons, Paul A; Kulkarni, Rohit N; Wagner, Bridget K

    2016-06-01

    Restoring functional β-cell mass is an important therapeutic goal for both type 1 and type 2 diabetes (1). While proliferation of existing β-cells is the primary means of β-cell replacement in rodents (2), it is unclear whether a similar principle applies to humans, as human β-cells are remarkably resistant to stimulation of division (3,4). Here, we show that 5-iodotubercidin (5-IT), an annotated adenosine kinase inhibitor previously reported to increase proliferation in rodent and porcine islets (5), strongly and selectively increases human β-cell proliferation in vitro and in vivo. Remarkably, 5-IT also increased glucose-dependent insulin secretion after prolonged treatment. Kinome profiling revealed 5-IT to be a potent and selective inhibitor of the dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) and cell division cycle-like kinase families. Induction of β-cell proliferation by either 5-IT or harmine, another natural product DYRK1A inhibitor, was suppressed by coincubation with the calcineurin inhibitor FK506, suggesting involvement of DYRK1A and nuclear factor of activated T cells signaling. Gene expression profiling in whole islets treated with 5-IT revealed induction of proliferation- and cell cycle-related genes, suggesting that true proliferation is induced by 5-IT. Furthermore, 5-IT promotes β-cell proliferation in human islets grafted under the kidney capsule of NOD-scid IL2Rg(null) mice. These results point to inhibition of DYRK1A as a therapeutic strategy to increase human β-cell proliferation. PMID:26953159

  10. The mechanism of inhibition of endothelin-1-induced stimulation of DNA synthesis in rat articular chondrocytes.

    PubMed

    Khatib, A M; Ribault, D; Quintero, M; Barbara, A; Fiet, J; Mitrovic, D R

    1997-09-19

    Endothelin-1 (ET-1) is a potent mitogen for rat articular chondrocytes (AC) in short term culture (24 h). Prolonged incubation (72 h) of AC with ET-1 resulted in inhibition of [3H]thymidine incorporation. This inhibition seemed to be mediated by prostaglandins (PGs) released in response to ET-1, since indomethacin (INDO) enhanced ET-1-induced [3H]thymidine incorporation. In agreement with this hypothesis, exogenous prostaglandins (PGE2, PGF2alpha and TxB2) blocked all basal, ET-1-induced and ET-1 induced-INDO-enhanced [3H]thymidine incorporation and ET-1 stimulated PGE2 release in a time and concentration-dependent manner. INDO also blocked cGMP production and 6-anilino-5,8-quinolinedione, a relatively specific inhibitor of cGMP formation, enhanced the stimulation and suppressed the inhibition of ET-1-induced DNA synthesis. In addition, 8-bromo-cGMP, an analogue of cGMP, blocked at all time periods studied, both basal and ET-1-induced incorporations of [3H]thymidine. Thus, PGs produced in response to ET-1 counteract the ET-1-induced stimulation of [3H]thymidine incorporation into rat AC by increasing cGMP production. PMID:9324043

  11. Dopamine inhibits maitotoxin-stimulated pituitary /sup 45/Ca/sup 2 +/ efflux and prolactin release

    SciTech Connect

    Login, I.S.; Judd, A.M.; MacLeod, R.M.

    1986-06-01

    The authors examined the hypothesis that dopaminergic inhibition of prolactin release is coupled to modulation of cellular calcium flux. Dispersed female rat pituitary cells were prelabeled in /sup 45/Ca/sup 2 +/ and perifused to determine simultaneously fractional calcium efflux and prolactin release, as stimulated by maitotoxin, a calcium channel activator. The integrated response of each parameter to 5 ng/ml maitotoxin was obtained in individual perifusion columns in the absence or presence of various concentrations of dopamine. Maitotoxin-stimulated calcium efflux was suppressed by dopamine concentrations of 0.01 ..mu..M and greater and achieved a maximal effect at approx.0.1 ..mu..M, at which calcium efflux was reduced by 50%. Maitotoxin-stimulated prolactin release was inhibited by 0.03 ..mu..M dopamine and greater concentrations, and at a concentration of approx.10.0 ..mu..M dopamine the effect became maximal at approx.85% suppression. Haloperidol (0.1 ..mu..M) blocked the effects of 0.1 ..mu..M dopamine on both parameters. Simultaneous suppression of maitotoxin-stimulated calcium efflux and prolactin release by concentrations of dopamine within the nonomolar range suggests that dopamine receptor activation is negatively coupled to modulation of calcium flux in the physiological regulation of prolactin secretion.

  12. The effects of transcranial direct current stimulation over the dorsolateral prefrontal cortex on cognitive inhibition.

    PubMed

    Metzuyanim-Gorlick, Shlomit; Mashal, Nira

    2016-06-01

    The present study examines the effects of bilateral transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) (anodal over left and cathodal over right DLPFC). This study describes the long-term effects of tDCS on cognitive inhibition, using the Hayling task. Twenty volunteers participated in the study and were assigned to either an active or a sham group. Participants heard sentences with the final word missing. They were asked then to complete the sentence with a word that either is appropriate in the context of the sentence (initiation condition) or is completely unrelated in this specific context (suppression condition). All participants performed a baseline Hayling task followed by six stimulation sessions. Subsequent to completion of these stimulations, we assessed immediately Hayling performance and re-assessed this performance 1 month. The results indicate a significant decrease in the number of errors in the active group, but only in the suppression condition that continued for 1 month after the sixth stimulation. The current findings suggest that tDCS can improve cognitive inhibition for the long-term in healthy adults and that the DLPFC has a special role in selecting the correct response and suppressing irrelevant semantic information. PMID:26821316

  13. Leptin inhibits gonadotrophin-stimulated granulosa cell progesterone production by antagonizing insulin action.

    PubMed

    Brannian, J D; Zhao, Y; McElroy, M

    1999-06-01

    Recent evidence has demonstrated that expression of leptin and leptin receptors is expected in the human ovary, and that leptin alters ovarian steroidogenesis in animal models. This study was designed to determine whether leptin modulates basal, gonadotrophin-, and insulin-stimulated progesterone production by human luteinized granulosa cells (GC). GC were recovered from follicular aspirates obtained during transvaginal ultrasound-guided oocyte retrieval for in-vitro fertilization-embryo transfer, and cultured in defined medium with various combinations of chorionic gonadotrophin (HCG; 0 or 100 ng/ml), insulin (0-30 microg/ml), and leptin (0-100 ng/ml). Progesterone concentrations in media were determined at various time points (2 h to 6 days). Leptin time- and dose-dependently inhibited (P < 0.05) HCG-stimulated progesterone production by human luteinized GC, but did not alter basal steroidogenesis. Moreover, the inhibitory effect of leptin on gonadotrophin-stimulated progesterone production was only manifested in the presence of insulin. Leptin suppression of insulin-supported steroidogenesis was also time- and dose-dependent. We conclude that leptin inhibits gonadotrophin-stimulated GC progesterone production apparently by antagonizing insulin action. Leptin suppression of progesterone production by human luteinized GC is consistent with recent data from animal models, and supports the possible role of leptin as a regulator of human ovarian function. PMID:10357956

  14. Unprecedentedly Strong and Narrow Electromagnetic Emissions Stimulated by High-Frequency Radio Waves in the Ionosphere

    SciTech Connect

    Norin, L.; Leyser, T. B.; Nordblad, E.; Thide, B.; McCarrick, M.

    2009-02-13

    Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.

  15. Unprecedentedly strong and narrow electromagnetic emissions stimulated by high-frequency radio waves in the ionosphere.

    PubMed

    Norin, L; Leyser, T B; Nordblad, E; Thidé, B; McCarrick, M

    2009-02-13

    Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA. PMID:19257596

  16. Strongly Enhanced Stimulated Brillouin Backscattering in an Electron-Positron Plasma

    NASA Astrophysics Data System (ADS)

    Edwards, Matthew R.; Fisch, Nathaniel J.; Mikhailova, Julia M.

    2016-01-01

    Stimulated Brillouin backscattering of light is shown to be drastically enhanced in electron-positron plasmas, in contrast to the suppression of stimulated Raman scattering. A generalized theory of three-wave coupling between electromagnetic and plasma waves in two-species plasmas with arbitrary mass ratios, confirmed with a comprehensive set of particle-in-cell simulations, reveals violations of commonly held assumptions about the behavior of electron-positron plasmas. Specifically, in the electron-positron limit three-wave parametric interaction between light and the plasma acoustic wave can occur, and the acoustic wave phase velocity differs from its usually assumed value.

  17. Modulation of motor activity by cutaneous input: inhibition of the magnetic motor evoked potential by digital electrical stimulation.

    PubMed

    Clouston, P D; Kiers, L; Menkes, D; Sander, H; Chiappa, K; Cros, D

    1995-04-01

    We examined the inhibitory effect of a brief train of digital (D2) electrical stimuli at 4 times perception threshold on transcranial magnetic motor evoked potentials (MEPs) recorded from abductor pollicis brevis (APB) and flexor carpi radialis (FCR) muscles ipsilateral to the side of D2 stimulation. We compared this to the inhibitory effect of ipsilateral D2 stimulation on averaged rectified EMG recorded at 10% maximum voluntary contraction and on F-responses and H-reflexes recorded from these same muscles. We also compared MEPs recorded following D2 stimulation just above perception threshold to MEPs following higher intensity D2 stimulation. As well, we assessed the effect of preceding D2 stimulation on MEPs recorded from a relaxed versus tonically contracted hand muscle. D2 stimulation elicited a triphasic response of modest MEP facilitation followed by inhibition and further facilitation. The duration and onset of MEP inhibition correlated with those of the initial period of rectified EMG inhibition, however, the magnitude of MEP inhibition was generally less than the magnitude of EMG inhibition, consistent with a greater inhibitory effect of digital afferents on smaller motor neurons. MEPs were not facilitated during the rebound of EMG activity (the E2 period) that usually followed the initial period of EMG inhibition (I1 period). The behavior of H-reflexes and F-responses following ipsilateral D2 stimulation suggested that inhibition of both EMG and MEPs is not mediated via presynaptic inhibition of Ia afferents, and that inhibition is augmented by descending rather than segmental input to spinal motor neurons. Tonic contraction of the target muscle during D2 stimulation decreased the inhibitory effect of the preceding digital stimulus possibly due to recruitment of larger spinal motor neurons less likely to be inhibited by cutaneous input. PMID:7537203

  18. Beta2-adrenergic receptor stimulation inhibits nitric oxide generation by Mycobacterium avium infected macrophages.

    PubMed

    Boomershine, C S; Lafuse, W P; Zwilling, B S

    1999-11-01

    Catecholamine regulation of nitric oxide (NO) production by IFNgamma-primed macrophages infected with Mycobacterium avium was investigated. Epinephrine treatment of IFNgamma-primed macrophages at the time of M. avium infection inhibited the anti-mycobacterial activity of the cells. The anti-mycobacterial activity of macrophages correlated with NO production. Using specific adrenergic receptor agonists, the abrogation of mycobacterial killing and decreased NO production by catecholamines was shown to be mediated via the beta2-adrenergic receptor. Elevation of intracellular cAMP levels mimicked the catecholamine-mediated inhibition of NO in both M. avium infected and LPS stimulated macrophages. Specific inhibitors of both adenylate cyclase and protein kinase A prevented the beta2-adrenoceptor-mediated inhibition of nitric oxide production. Beta2-adrenoreceptor stimulation at the time of M. avium infection of IFNgamma-primed macrophages also inhibited expression of iNOS mRNA. These observations show that catecholamine hormones can affect the outcome of macrophage-pathogen interactions and suggest that one result of sympathetic nervous system activation is the suppression of the capacity of macrophages to produce anti-microbial effector molecules. PMID:10580815

  19. Inhibition of FOXP3/NFAT Interaction Enhances T Cell Function after TCR Stimulation.

    PubMed

    Lozano, Teresa; Villanueva, Lorea; Durántez, Maika; Gorraiz, Marta; Ruiz, Marta; Belsúe, Virginia; Riezu-Boj, José I; Hervás-Stubbs, Sandra; Oyarzábal, Julen; Bandukwala, Hozefa; Lourenço, Ana R; Coffer, Paul J; Sarobe, Pablo; Prieto, Jesús; Casares, Noelia; Lasarte, Juan J

    2015-10-01

    Regulatory T cell (Treg) activity is modulated by a cooperative complex between the transcription factor NFAT and FOXP3, a lineage specification factor for Tregs. FOXP3/NFAT interaction is required to repress expression of IL-2, upregulate expression of the Treg markers CTLA4 and CD25, and confer suppressor function to Tregs. However, FOXP3 is expressed transiently in conventional CD4(+) T cells upon TCR stimulation and may lead to T cell hyporesponsiveness. We found that a short synthetic peptide able to inhibit FOXP3/NFAT interaction impaired suppressor activity of conventional Tregs in vitro. Specific inhibition of FOXP3/NFAT interaction with this inhibitory peptide revealed that FOXP3 downregulates NFAT-driven promoter activity of CD40L and IL-17. Inhibition of FOXP3/NFAT interaction upregulated CD40L expression on effector T cells and enhanced T cell proliferation and IL-2, IFN-γ, IL-6, or IL-17 production in response to TCR stimulation. The inhibitory peptide impaired effector T cell conversion into induced Tregs in the presence of TGF-β. Moreover, in vivo peptide administration showed antitumor efficacy in mice bearing Hepa129 or TC1 tumor cells when combined with sorafenib or with an antitumor vaccine, respectively. Our results suggest that inhibition of NFAT/FOXP3 interaction might improve antitumor immunotherapies. PMID:26324768

  20. trans-Resveratrol inhibits calcium influx in thrombin-stimulated human platelets

    PubMed Central

    Dobrydneva, Yuliya; Williams, Roy L; Blackmore, Peter F

    1999-01-01

    The phytoestrogenic compound trans-resveratrol (trans-3,5,4′-trihydroxystilbene) is found in appreciable quantities in grape skins and wine. It has been shown that both products rich in trans-resveratrol and pure trans-resveratrol inhibit platelet aggregation both in vivo and in vitro. However the mechanism of this action still remains unknown. An essential component of the aggregation process in platelets is an increase in intracellular free Ca2+ ([Ca2+]i). Ca2+ must enter the cell from the external media through specific and tightly regulated Ca2+ channels in the plasma membrane. The objective of this study was to characterize what effect trans-resveratrol had on the Ca2+ channels in thrombin stimulated platelets. In this study we showed that trans-resveratrol immediately inhibited Ca2+ influx in thrombin-stimulated platelets with an IC50 of 0.5 μM. trans-Resveratrol at 0.1, 1.0 and 10.0 μM produced 20±6, 37±6 and 57±4% inhibition respectively of the effect of thrombin (0.01 u  ml−1) to increase [Ca2+]i. trans-Resveratrol also inhibited spontaneous Ba2+ entry into Fura-2 loaded platelets, with 0.1, 1.0 and 10.0 μM trans-resveratrol producing 10±5, 30±5 and 50±7% inhibition respectively. This indicated that trans-resveratrol directly inhibited Ca2+ channel activity in the platelets in the absence of agonist stimulation. trans-Resveratrol also inhibited thapsigargin-mediated Ca2+ influx into platelets. This suggests that the store-operated Ca2+ channels are one of the possible targets of trans-resveratrol. These channels rely on the emptying of the internal Ca2+ stores to initiate influx of Ca2+ into the cell. The phytoestrogens genistein, daidzein, apigenin and genistein-glucoside (genistin) produced inhibitory effects against thrombin similar to those seen with trans-resveratrol. We conclude that trans-resveratrol is an inhibitor of store-operated Ca2+ channels in human platelets. This accounts for the ability of trans-resveratrol to

  1. Polarity specific effects of transcranial direct current stimulation on interhemispheric inhibition.

    PubMed

    Tazoe, Toshiki; Endoh, Takashi; Kitamura, Taku; Ogata, Toru

    2014-01-01

    Transcranial direct current stimulation (tDCS) has been used as a useful interventional brain stimulation technique to improve unilateral upper-limb motor function in healthy humans, as well as in stroke patients. Although tDCS applications are supposed to modify the interhemispheric balance between the motor cortices, the tDCS after-effects on interhemispheric interactions are still poorly understood. To address this issue, we investigated the tDCS after-effects on interhemispheric inhibition (IHI) between the primary motor cortices (M1) in healthy humans. Three types of tDCS electrode montage were tested on separate days; anodal tDCS over the right M1, cathodal tDCS over the left M1, bilateral tDCS with anode over the right M1 and cathode over the left M1. Single-pulse and paired-pulse transcranial magnetic stimulations were given to the left M1 and right M1 before and after tDCS to assess the bilateral corticospinal excitabilities and mutual direction of IHI. Regardless of the electrode montages, corticospinal excitability was increased on the same side of anodal stimulation and decreased on the same side of cathodal stimulation. However, neither unilateral tDCS changed the corticospinal excitability at the unstimulated side. Unilateral anodal tDCS increased IHI from the facilitated side M1 to the unchanged side M1, but it did not change IHI in the other direction. Unilateral cathodal tDCS suppressed IHI both from the inhibited side M1 to the unchanged side M1 and from the unchanged side M1 to the inhibited side M1. Bilateral tDCS increased IHI from the facilitated side M1 to the inhibited side M1 and attenuated IHI in the opposite direction. Sham-tDCS affected neither corticospinal excitability nor IHI. These findings indicate that tDCS produced polarity-specific after-effects on the interhemispheric interactions between M1 and that those after-effects on interhemispheric interactions were mainly dependent on whether tDCS resulted in the facilitation or

  2. Methylprednisolone inhibits uptake of Ca2+ and Na+ ions into concanavalin A-stimulated thymocytes.

    PubMed Central

    Buttgereit, F; Krauss, S; Brand, M D

    1997-01-01

    The glucocorticoid drug methylprednisolone inhibits respiration in concanavalin A-stimulated rat thymocytes at concentrations that are relevant to its acute clinical efficacy against autoimmune diseases and spinal cord injury. Methylprednisolone affects several processes, including ion cycling, substrate oxidation reactions and RNA/DNA synthesis. The inhibition of respiration used to drive ATP-consuming cycles of Ca2+ and Na+ ions across the plasma membrane has been proposed to be either primary or secondary to restriction of cellular ATP supply. By comparing the effects of methylprednisolone with those of myxothiazol, an inhibitor of the mitochondrial electron transport chain, we show that the effects of methylprednisolone on Ca2+ and Na+ cycling are primary. We propose that methylprednisolone acts by affecting membrane properties to inhibit Ca2+ and Na+ uptake across the plasma membrane and to increase H+ uptake across the mitochondrial membrane, and that other effects are secondary. PMID:9291100

  3. Curcumin inhibits bTREK-1 K+ channels and stimulates cortisol secretion from adrenocortical cells

    PubMed Central

    Enyeart, Judith A.; Liu, Haiyan; Enyeart, John J.

    2008-01-01

    Bovine adrenal zona fasciculata (AZF) cells express bTREK-1 K+ channels that set the resting membrane potential. Inhibition of these channels by adrenocorticotropic hormone (ACTH) is coupled to membrane depolarization and cortisol secretion. Curcumin, a phytochemical with medicinal properties extracted from the spice turmeric, was found to modulate both bTREK-1 K+ currents and cortisol secretion from AZF cells. In whole-cell patch clamp experiments, curcumin inhibited bTREK-1 with an IC50 of 0.93μM by a mechanism that was voltage-independent. bTREK-1 inhibition by curcumin occurred through interaction with an external binding site and was independent of ATP hydrolysis. Curcumin produced a concentration-dependent increase in cortisol secretion that persisted for up to 24 h. At a maximally effective concentration of 50 μM, curcumin increased secretion as much as10-fold. These results demonstrate that curcumin potently inhibits bTREK-1 K+ channels and stimulates cortisol secretion from bovine AZF cells. The inhibition of bTREK-1 by curcumin may be linked to cortisol secretion through membrane depolarization. Since TREK-1 is widely expressed in a variety of cells, it is likely that some of the biological actions of curcumin, including its therapeutic effects, may be mediated through inhibition of these K+ channels. PMID:18406348

  4. Silymarin Inhibits Morphological Changes in LPS-Stimulated Macrophages by Blocking NF-κB Pathway

    PubMed Central

    Kim, Eun Jeong; Lee, Min Young

    2015-01-01

    The present study showed that silymarin, a polyphenolic flavonoid isolated from milk thistle (Silybum marianum), inhibited lipopolysaccharide (LPS)-induced morphological changes in the mouse RAW264.7 macrophage cell line. We also showed that silymarin inhibited the nuclear translocation and transactivation activities of nuclear factor-kappa B (NF-κB), which is important for macrophage activation-associated changes in cell morphology and gene expression of inflammatory cytokines. BAY-11-7085, an NF-κB inhibitor, abrogated LPS-induced morphological changes and NO production, similar to silymarin. Treatment of RAW264.7 cells with silymarin also inhibited LPS-stimulated activation of mitogen-activated protein kinases (MAPKs). Collectively, these experiments demonstrated that silymarin inhibited LPS-induced morphological changes in the RAW264.7 mouse macrophage cell line. Our findings indicated that the most likely mechanism underlying this biological effect involved inhibition of the MAPK pathway and NF-κB activity. Inhibition of these activities by silymarin is a potentially useful strategy for the treatment of inflammation because of the critical roles played by MAPK and NF-κB in mediating inflammatory responses in macrophages. PMID:25954125

  5. Measures of cortical inhibition by paired-pulse transcranial magnetic stimulation in anesthetized rats.

    PubMed

    Vahabzadeh-Hagh, Andrew M; Muller, Paul A; Pascual-Leone, Alvaro; Jensen, Frances E; Rotenberg, Alexander

    2011-02-01

    Paired-pulse transcranial magnetic stimulation (ppTMS) is a noninvasive method to measure cortical inhibition in vivo. Long interpulse interval (50-500 ms) ppTMS (LI-ppTMS) provokes intracortical inhibitory circuits and can reveal pathologically impaired cortical inhibition in disorders such as epilepsy. Adaptation of ppTMS protocols to rodent disease models is highly desirable to facilitate basic and translational research. We previously adapted single-pulse TMS (spTMS) methods to rats, but ppTMS has yet to be applied. Specifically, whether ppTMS elicits an inhibitory response in rodents is unknown. ppTMS in rats also requires anesthesia, a setting under which the preservation of these measures is undetermined. We therefore tested, in anesthetized rats, whether anesthetic choice affects spTMS-motor-evoked potentials (MEPs), LI-ppTMS in rats, as in humans, elicits intracortical inhibition of the MEP, and rat LI-ppTMS inhibition is acutely impaired in a seizure model. Rats were anesthetized with pentobarbital (PB) or ketamine-atropine-xylazine (KAX) and stimulated unilaterally over the motor cortex while recording bilateral brachioradialis MEPs. LI-ppTMS was applied analogous to human long interval intracortical inhibition (LICI) protocols, and acute changes in inhibition were evaluated following injection of the convulsant pentylenetetrazole (PTZ). We find that spTMS-evoked MEPs were reliably present under either anesthetic, and that LI-ppTMS elicits inhibition of the conditioned MEP in rats, similar to human LICI, by as much as 58 ± 12 and 71 ± 11% under PB and KAX anesthesia, respectively. LI-ppTMS inhibition was reduced to as much as 53% of saline controls following PTZ injection, while spTMS-derived measures of corticospinal excitability were unchanged. Our data show that regional inhibition, similar to human LICI, is present in rats, can be elicited under PB or KAX anesthesia, and is reduced following convulsant administration. These results suggest a

  6. Inhibition of potassium-stimulated dopamine release by the nitric oxide generator isosorbide dinitrate.

    PubMed

    Sun, P; Kanthasamy, A; Yim, G K; Isom, G E

    1995-02-01

    In PC12 cells, isosorbide dinitrate (ISDN) and S-nitrosol-acetyl-penicillamine (SNAP), both nitric oxide (NO) generators, attenuated K+ (56 mM)-stimulated release of dopamine. The attenuation was not observed with isosorbide, an ISDN analog lacking NO generating capacity. In this model, A23187 (Ca2+ ionophore), Bay K8644 (Ca2+ slow channel agonist) and veratridine (Na+ channel agonist) stimulated dopamine release. Treatment with ISDN enhanced Bay K8644 and veratridine-evoked dopamine release, while ISDN had no significant effect on the A23187 response. Incubation with 8-bromo-cGMP (membrane permeable cGMP analog) had no effect on basal or stimulated dopamine release in these cells, suggesting NO's response was not mediated by cGMP. In additional studies, K+ (56 mM), Bay K8644 and veratridine elevated cytosolic free calcium levels ([Ca2+]i). ISDN reduced K(+)-stimulated increase in [Ca2+]i, but enhanced the increases of [Ca2+]i induced by Bay K8644 or veratridine. These results suggest NO interacts with K(+)-induced membrane depolarization (possibly by inhibiting membrane conductance to K+) to attenuate Ca2+ influx and Ca(2+)-mediated dopamine secretion stimulated by K+. PMID:7542370

  7. Sustained Inhibition of Proliferative Response After Transient FGF Stimulation Is Mediated by Interleukin 1 Signaling.

    PubMed

    Poole, Ashleigh; Kacer, Doreen; Cooper, Emily; Tarantini, Francesca; Prudovsky, Igor

    2016-03-01

    Transient FGF stimulation of various cell types results in FGF memory--a sustained blockage of efficient proliferative response to FGF and other growth factors. FGF memory establishment requires HDAC activity, indicating its epigenetic character. FGF treatment stimulates proinflammatory NFκB signaling, which is also critical for FGF memory formation. The search for FGF-induced mediators of FGF memory revealed that FGF stimulates HDAC-dependent expression of the inflammatory cytokine IL1α. Similarly to FGF, transient cell treatment with recombinant IL1α inhibits the proliferative response to further FGF and EGF stimulation, but does not prevent FGF receptor-mediated signaling. Interestingly, like cells pretreated with FGF1, cells pretreated with IL1α exhibit enhanced restructuring of actin cytoskeleton and increased migration in response to FGF stimulation. IRAP, a specific inhibitor of IL 1 receptor, and a neutralizing anti-IL1α antibody prevent the formation of FGF memory and rescue an efficient proliferative response to FGF restimulation. A similar effect results following treatment with the anti-inflammatory agents aspirin and dexamethasone. Thus, FGF memory is mediated by proinflammatory IL1 signaling. It may play a role in the limitation of proliferative response to tissue damage and prevention of wound-induced hyperplasia. PMID:26218437

  8. Extracellular Nucleotides Inhibit Insulin Receptor Signaling, Stimulate Autophagy and Control Lipoprotein Secretion

    PubMed Central

    Chatterjee, Cynthia; Sparks, Daniel L.

    2012-01-01

    Hyperglycemia is associated with abnormal plasma lipoprotein metabolism and with an elevation in circulating nucleotide levels. We evaluated how extracellular nucleotides may act to perturb hepatic lipoprotein secretion. Adenosine diphosphate (ADP) (>10 µM) acts like a proteasomal inhibitor to stimulate apoB100 secretion and inhibit apoA-I secretion from human liver cells at 4 h and 24 h. ADP blocks apoA-I secretion by stimulating autophagy. The nucleotide increases cellular levels of the autophagosome marker, LC3-II, and increases co-localization of LC3 with apoA-I in punctate autophagosomes. ADP affects autophagy and apoA-I secretion through P2Y13. Overexpression of P2Y13 increases cellular LC3-II levels by ∼50% and blocks induction of apoA-I secretion. Conversely, a siRNA-induced reduction in P2Y13 protein expression of 50% causes a similar reduction in cellular LC3-II levels and a 3-fold stimulation in apoA-I secretion. P2Y13 gene silencing blocks the effects of ADP on autophagy and apoA-I secretion. A reduction in P2Y13 expression suppresses ERK1/2 phosphorylation, increases the phosphorylation of IR-β and protein kinase B (Akt) >3-fold, and blocks the inhibition of Akt phosphorylation by TNFα and ADP. Conversely, increasing P2Y13 expression significantly inhibits insulin-induced phosphorylation of insulin receptor (IR-β) and Akt, similar to that observed after treatment with ADP. Nucleotides therefore act through P2Y13, ERK1/2 and insulin receptor signaling to stimulate autophagy and affect hepatic lipoprotein secretion. PMID:22590634

  9. Diterpenes from the roots of Oryza sativa L. and their inhibition activity on NO production in LPS-stimulated RAW264.7 macrophages.

    PubMed

    Cho, Jin-Gyeong; Cha, Byeong-Ju; Min Lee, Sang; Shrestha, Sabina; Jeong, Rak-Hun; Sung Lee, Dong; Kim, Youn-Chul; Lee, Dong-Geol; Kang, Hee-Cheol; Kim, Jiyoung; Baek, Nam-In

    2015-09-01

    Two new pimarane diterpenoids, momilactone D (3) and momilactone E (5), along with three known diterpenoids, momilactone A (1), sandaracopimaradien-3-one (2), and oryzalexin A (4) were isolated from Oryza sativa roots. The chemical structures of the compounds were determined by spectroscopic data analysis. The isolated diterpenoids were evaluated for their ability to inhibit NO production and iNOS mRNA and protein expression in LPS-stimulated RAW264.7 macrophages. Compound 4 showed strong inhibition activity on NO production, and compounds 1 and 4 decreased the expression of iNOS mRNA and protein levels. PMID:26363880

  10. Control of Stimulated Raman Scattering in the Strongly Nonlinear and Kinetic Regime Using Spike Trains of Uneven Duration and Delay

    NASA Astrophysics Data System (ADS)

    Albright, B. J.; Yin, L.; Afeyan, B.

    2014-07-01

    Stimulated Raman scattering (SRS) in its strongly nonlinear, kinetic regime is controlled by a technique of deterministic, strong temporal modulation and spatial scrambling of laser speckle patterns, called spike trains of uneven duration and delay (STUD) pulses [B. Afeyan and S. Hüller (unpublished)]. Kinetic simulations show that the proper use of STUD pulses decreases SRS reflectivity by more than an order of magnitude over random-phase-plate or induced-spatial-incoherence beams of the same average intensity and comparable bandwidth.

  11. Taxifolin glycoside inhibits dendritic cell responses stimulated by lipopolysaccharide and lipoteichoic acid.

    PubMed

    Kim, Yun Jeong; Choi, Sun Eun; Lee, Min Won; Lee, Chung Soo

    2008-11-01

    Antigen-presenting dendritic cells may play an important role in the pathogenesis of atopic dermatitis. Taxifolin is demonstrated to have anti-inflammatory effects. The present study was designed to assess the effect of taxifolin glycoside against stimulated responses of dendritic cells isolated from mouse bone marrow and spleen. Dendritic cells exposed to lipopolysaccharide, lipoteichoic acid or interleukin (IL)-1beta exhibited increased production of IL-12 p70 and tumour necrosis factor alpha, increased formation of reactive oxygen species (ROS) and nitric oxide (NO), and elevation of intracellular Ca2+ levels. Treatment with taxifolin glycoside inhibited responses stimulated by the microbial products or IL-1beta in dendritic cells in a dose-dependent manner. Taxifolin glycoside had a significant inhibitory effect on the production of cytokines, formation of ROS and NO, and change in intracellular Ca2+ levels in dendritic cells of bone marrow and spleen. The results show that taxifolin glycoside seems to inhibit the dendritic cell responses stimulated by microbial products and IL-1beta, suggesting that taxifolin glycoside may exert an inhibitory effect against dendritic-cell-mediated immune responses. PMID:18957167

  12. Effects of deep brain stimulation on prepulse inhibition in obsessive-compulsive disorder.

    PubMed

    Kohl, S; Gruendler, T O J; Huys, D; Sildatke, E; Dembek, T A; Hellmich, M; Vorderwulbecke, M; Timmermann, L; Ahmari, S E; Klosterkoetter, J; Jessen, F; Sturm, V; Visser-Vandewalle, V; Kuhn, J

    2015-01-01

    Owing to a high response rate, deep brain stimulation (DBS) of the ventral striatal area has been approved for treatment-refractory obsessive-compulsive disorder (tr-OCD). Many basic issues regarding DBS for tr-OCD are still not understood, in particular, the mechanisms of action and the origin of side effects. We measured prepulse inhibition (PPI) in treatment-refractory OCD patients undergoing DBS of the nucleus accumbens (NAcc) and matched controls. As PPI has been used in animal DBS studies, it is highly suitable for translational research. Eight patients receiving DBS, eight patients with pharmacological treatment and eight age-matched healthy controls participated in our study. PPI was measured twice in the DBS group: one session with the stimulator switched on and one session with the stimulator switched off. OCD patients in the pharmacologic group took part in a single session. Controls were tested twice, to ensure stability of data. Statistical analysis revealed significant differences between controls and (1) patients with pharmacological treatment and (2) OCD DBS patients when the stimulation was switched off. Switching the stimulator on led to an increase in PPI at a stimulus-onset asynchrony of 200 ms. There was no significant difference in PPI between OCD patients being stimulated and the control group. This study shows that NAcc-DBS leads to an increase in PPI in tr-OCD patients towards a level seen in healthy controls. Assuming that PPI impairments partially reflect the neurobiological substrates of OCD, our results show that DBS of the NAcc may improve sensorimotor gating via correction of dysfunctional neural substrates. Bearing in mind that PPI is based on a complex and multilayered network, our data confirm that DBS most likely takes effect via network modulation. PMID:26556284

  13. Secreted APE1/Ref-1 inhibits TNF-α-stimulated endothelial inflammation via thiol-disulfide exchange in TNF receptor

    PubMed Central

    Park, Myoung Soo; Choi, Sunga; Lee, Yu Ran; Joo, Hee Kyoung; Kang, Gun; Kim, Cuk-Seong; Kim, Soo Jin; Lee, Sang Do; Jeon, Byeong Hwa

    2016-01-01

    Apurinic apyrimidinic endonuclease 1/Redox factor-1 (APE1/Ref-1) is a multifunctional protein with redox activity and is proved to be secreted from stimulated cells. The aim of this study was to evaluate the functions of extracellular APE1/Ref-1 with respect to leading anti-inflammatory signaling in TNF-α-stimulated endothelial cells in response to acetylation. Treatment of TNF-α-stimulated endothelial cells with an inhibitor of deacetylase that causes intracellular acetylation, considerably suppressed vascular cell adhesion molecule-1 (VCAM-1). During TSA-mediated acetylation in culture, a time-dependent increase in secreted APE1/Ref-1 was confirmed. The acetyl moiety of acetylated-APE1/Ref-1 was rapidly removed based on the removal kinetics. Additionally, recombinant human (rh) APE1/Ref-1 with reducing activity induced a conformational change in rh TNF-α receptor 1 (TNFR1) by thiol-disulfide exchange. Following treatment with the neutralizing anti-APE1/Ref-1 antibody, inflammatory signals via the binding of TNF-α to TNFR1 were remarkably recovered, leading to up-regulation of reactive oxygen species generation and VCAM-1, in accordance with the activation of p66shc and p38 MAPK. These results strongly indicate that anti-inflammatory effects in TNF-α-stimulated endothelial cells by acetylation are tightly linked to secreted APE1/Ref-1, which inhibits TNF-α binding to TNFR1 by reductive conformational change, with suggestion as an endogenous inhibitor of vascular inflammation. PMID:26964514

  14. Bioactive Extract from Moringa oleifera Inhibits the Pro-inflammatory Mediators in Lipopolysaccharide Stimulated Macrophages

    PubMed Central

    Fard, Masoumeh Tangestani; Arulselvan, Palanisamy; Karthivashan, Govindarajan; Adam, Siti Khadijah; Fakurazi, Sharida

    2015-01-01

    Introduction: Inflammation is a well-known physiological response to protect the body against infection and restore tissue injury. Nevertheless, the chronic inflammation can trigger various inflammatory associated diseases/disorder. Moringa oleifera is a widely grown plant in most tropical countries and it has been recognized traditionally for several medicinal benefits. Objectives: The objective of this study was to investigate the anti-inflammatory properties of M. oleifera extract on lipopolysaccharide (LPS) - stimulated macrophages. Materials and Methods: The anti-inflammatory effect of M. oleifera hydroethanolic bioactive leaves extracts was evaluated by assessing the inhibition of nitric oxide (NO) production during Griess reaction and the expression of pro-inflammatory mediators in macrophages. Results: Interestingly, we found that M. oleifera hydroethanolic bioactive leaves extract significantly inhibited the secretion of NO production and other inflammatory markers such as prostaglandin E2, tumor necrosis factor alpha, interleukin (IL)-6, and IL-1β. Meanwhile, the bioactive extract has induced the production of IL-10 in a dose-dependent manner. In addition, M. oleifera hydroethanolic bioactive leaves extract effectively suppressed the protein expression of inflammatory markers inducible NO synthase, cyclooxygenase-2, and nuclear factor kappa-light-chain-enhancer of activated B-cells p65 in LPS-induced RAW264.7 macrophages in a dose-dependent manner. Conclusion: These findings support the traditional use of M. oleifera plant as an effective treatment for inflammation associated diseases/disorders. SUMMARY Hydroethanolic extracts of Moringa oleifera effectively inhibit the NO production in LPS induced inflammatory model.M. oleifera crude extracts successfully modulate the production of pro-inflammatory mediators in LPS stimulated macrophages.M. oleifera extracts suppressed the expression of inflammatory mediators in LPS stimulated macrophages. PMID:27013794

  15. A selective TSH receptor antagonist inhibits stimulation of thyroid function in female mice.

    PubMed

    Neumann, Susanne; Nir, Eshel A; Eliseeva, Elena; Huang, Wenwei; Marugan, Juan; Xiao, Jingbo; Dulcey, Andrés E; Gershengorn, Marvin C

    2014-01-01

    Because the TSH receptor (TSHR) plays an important role in the pathogenesis of thyroid disease, a TSHR antagonist could be a novel treatment. We attempted to develop a small molecule, drug-like antagonist of TSHR signaling that is selective and active in vivo. We synthesized NCGC00242364 (ANTAG3) by chemical modification of a previously reported TSHR antagonist. We tested its potency, efficacy, and selectivity in a model cell system in vitro by measuring its activity to inhibit stimulation of cAMP production stimulated by TSH, LH, or FSH. We tested the in vivo activity of ANTAG3 by measuring its effects to lower serum free T4 and thyroid gene expression in female BALB/c mice continuously treated with ANTAG3 for 3 days and given low doses of TRH continuously or stimulated by a single administration of a monoclonal thyroid-stimulating antibody M22. ANTAG3 was selective for TSHR inhibition; half-maximal inhibitory doses were 2.1 μM for TSHR and greater than 30 μM for LH and FSH receptors. In mice treated with TRH, ANTAG3 lowered serum free T4 by 44% and lowered mRNAs for sodium-iodide cotransporter and thyroperoxidase by 75% and 83%, respectively. In mice given M22, ANTAG3 lowered serum free T4 by 38% and lowered mRNAs for sodium-iodide cotransporter and thyroperoxidase by 73% and 40%, respectively. In conclusion, we developed a selective TSHR antagonist that is effective in vivo in mice. This is the first report of a small-molecule TSHR antagonist active in vivo and may lead to a drug to treat Graves' disease. PMID:24169564

  16. Inhibition of sham feeding-stimulated acid secretion in dogs by immunoneutralization of gastrin.

    PubMed

    Kovacs, T O; Lloyd, K C; Lawson, D C; Pappas, T N; Walsh, J H

    1997-08-01

    A monoclonal antibody to gastrin was used to study the role of circulating gastrin in mediating acid secretion stimulated by sham feeding in dogs. On separate days, four conscious, fasted, adult mongrel dogs with esophageal and gastric fistulae were pretreated intravenously with either 7 mg of gastrin monoclonal antibody (MAb 28.2), 7 mg of keyhole limpet hemocyanin monoclonal antibody as control, or 12.5 micrograms/kg atropine sulfate. Thirty minutes later, acid secretion was stimulated first by sham feeding for 5 min, then, 60 min later, by an intravenous infusion of a maximum stimulatory dose of histamine (40 micrograms/kg) for 60 min, and after returning to basal, by intravenous infusion of a submaximal stimulatory dose of gastrin (200 pmol.kg-1.h-1) for 60 min. Acid output from secretions collected every 15 min by gravity drainage was determined by titration to pH 7.0 with 0.2 N NaOH. Sham feeding-stimulated acid output (17.7 +/- 5.5 mmol/h) was significantly inhibited by administration of either MAb 28.2 (0 mmol/h) or atropine (1.7 +/- 1.1 mmol/h). Histamine-stimulated acid output (19.6 +/- 3.4 mmol/h) was not reduced by either pretreatment. Gastrin-stimulated acid output (3.9 +/- 0.6 mmol/h) was significantly reduced only by pretreatment with MAb 28.2 (0.1 +/- 0.1 mmol/h) and not by atropine (2.2 +/- 1.4 mmol/h). A background intravenous infusion of pentagastrin (0.5 microgram.kg-1.h-1) restored sham feeding-stimulated acid output blocked by administration of MAb 28.2, although the intrinsic acid response to sham feeding could not be seen with the background pentagastrin infusion. Furthermore, the plasma gastrin response to sham feeding was not blocked by atropine pretreatment. Because immunoneutralization of both gastrin and cholinergic blockade significantly inhibited acid output during sham feeding, circulating gastrin and cholinergic pathways are involved in mediating the cephalic phase of gastric acid secretion in dogs. PMID:9277419

  17. Benzo[b]quinolizinium Derivatives Have a Strong Antimalarial Activity and Inhibit Indoleamine Dioxygenase

    PubMed Central

    Jortzik, Esther; Zocher, Kathleen; Isernhagen, Antje; Mailu, Boniface M.; Rahlfs, Stefan; Viola, Giampietro; Wittlin, Sergio; Hunt, Nicholas H.; Ihmels, Heiko

    2015-01-01

    The heme-containing enzymes indoleamine 2,3-dioxygenase-1 (IDO-1) and IDO-2 catalyze the conversion of the essential amino acid tryptophan into kynurenine. Metabolites of the kynurenine pathway and IDO itself are involved in immunity and the pathology of several diseases, having either immunoregulatory or antimicrobial effects. IDO-1 plays a central role in the pathogenesis of cerebral malaria, which is the most severe and often fatal neurological complication of infection with Plasmodium falciparum. Mouse models are usually used to study the underlying pathophysiology. In this study, we screened a natural compound library against mouse IDO-1 and identified 8-aminobenzo[b]quinolizinium (compound 2c) to be an inhibitor of IDO-1 with potency at nanomolar concentrations (50% inhibitory concentration, 164 nM). Twenty-one structurally modified derivatives of compound 2c were synthesized for structure-activity relationship analyses. The compounds were found to be selective for IDO-1 over IDO-2. We therefore compared the roles of prominent amino acids in the catalytic mechanisms of the two isoenzymes via homology modeling, site-directed mutagenesis, and kinetic analyses. Notably, methionine 385 of IDO-2 was identified to interfere with the entrance of l-tryptophan to the active site of the enzyme, which explains the selectivity of the inhibitors. Most interestingly, several benzo[b]quinolizinium derivatives (6 compounds with 50% effective concentration values between 2.1 and 6.7 nM) were found to be highly effective against P. falciparum 3D7 blood stages in cell culture with a mechanism independent of IDO-1 inhibition. We believe that the class of compounds presented here has unique characteristics; it combines the inhibition of mammalian IDO-1 with strong antiparasitic activity, two features that offer potential for drug development. PMID:26459907

  18. Plasma leptin inhibits the response of nucleus of the solitary tract neurons to aortic baroreceptor stimulation.

    PubMed

    Ciriello, John

    2013-08-01

    Leptin receptors have been identified within the nucleus of the solitary tract (NTS) and leptin injections into the caudal NTS inhibit the baroreceptor reflex. However, whether plasma leptin alters the discharge of NTS neurons mediating aortic baroreceptor reflex activity is not known. A series of electrophysiological single unit recording experiments was done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar and Zucker obese rat with either their neuroaxis intact or with mid-collicular transections. Single units in NTS antidromically activated by electrical stimulation of depressor sites in the caudal ventrolateral medulla (CVLM) were found to display a cardiac cycle-related rhythmicity. These units were tested for their responses to stimulation of the aortic depressor nerve (ADN) and intra-carotid injections of leptin (50-200ng/0.1ml). Of 63 single units tested in NTS, 33 were antidromically activated by stimulation of CVLM depressor sites and 18 of these single units responded with a decrease in discharge rate after intracarotid injections of leptin. Thirteen of these leptin responsive neurons (∼72%) were excited by ADN stimulation. Furthermore, the excitatory response of these single units to ADN stimulation was attenuated by about 50% after the intracarotid leptin injection. Intracarotid injections of leptin (200ng/0.1ml) in the Zucker obese rat did not alter the discharge rate of NTS-CVLM projecting neurons. These data suggest that leptin exerts a modulatory effect on brainstem neuronal circuits that control cardiovascular responses elicited during the reflex activation of arterial baroreceptors. PMID:23792336

  19. Acupuncture inhibits vagal gastric acid secretion stimulated by sham feeding in healthy subjects.

    PubMed

    Lux, G; Hagel, J; Bäcker, P; Bäcker, G; Vogl, R; Ruppin, H; Domschke, S; Domschke, W

    1994-08-01

    In a prospective randomised study, the effect of acupuncture on sham feeding stimulated gastric acid secretion was investigated. In eight healthy volunteers (five men, three women, mean (SEM) age 26.3 (4.7) years) various methods of acupuncture were performed. Apart from the sham procedure, the acupuncture was performed at the classic acupuncture points. Electroacupuncture reduced gastric acid secretion expressed as median (range) significantly during the first 30 minute period to 1.6 (0-5.2) mmol compared with 3.8 (2.3-14.5) mmol (p < 0.05) during control period (sham feeding without acupuncture). Inhibition of gastric acid secretion by electroacupuncture was also significant during the second 30 minute period (0.2 (0-5.6) v 3.6 (0.3-9.1) mmol; p < 0.05) and for peak acid output (0.8 (0.2-5.1) v 7.6 (3.4-12.1) mmol; p < 0.05). Transcutaneous electrical nerve stimulation also resulted in significant reduction of gastric acid secretion during the first 30 minute period (1.0 (0-3.6) mmol v 3.8 (2.3-14.5) mmol; p < 0.05), and peak acid output (3.6 (1.2-12.0) v 7.6 (3.4-12.1) mmol; p < 0.05). The classic needle acupuncture, laser acupuncture, and sham acupuncture had no significant effect on gastric acid secretion. This study shows firstly that in healthy volunteers, only the versions of acupuncture using more pronounced stimulation (electroacupuncture, transcutaneous electrical nerve stimulation), but not those with only mild stimulation of the nerves (classic needle acupuncture, laser acupuncture), and secondly only acupuncture performed at defined points lead to significant reduction in gastric acid secretion. PMID:7926899

  20. Acupuncture inhibits vagal gastric acid secretion stimulated by sham feeding in healthy subjects.

    PubMed Central

    Lux, G; Hagel, J; Bäcker, P; Bäcker, G; Vogl, R; Ruppin, H; Domschke, S; Domschke, W

    1994-01-01

    In a prospective randomised study, the effect of acupuncture on sham feeding stimulated gastric acid secretion was investigated. In eight healthy volunteers (five men, three women, mean (SEM) age 26.3 (4.7) years) various methods of acupuncture were performed. Apart from the sham procedure, the acupuncture was performed at the classic acupuncture points. Electroacupuncture reduced gastric acid secretion expressed as median (range) significantly during the first 30 minute period to 1.6 (0-5.2) mmol compared with 3.8 (2.3-14.5) mmol (p < 0.05) during control period (sham feeding without acupuncture). Inhibition of gastric acid secretion by electroacupuncture was also significant during the second 30 minute period (0.2 (0-5.6) v 3.6 (0.3-9.1) mmol; p < 0.05) and for peak acid output (0.8 (0.2-5.1) v 7.6 (3.4-12.1) mmol; p < 0.05). Transcutaneous electrical nerve stimulation also resulted in significant reduction of gastric acid secretion during the first 30 minute period (1.0 (0-3.6) mmol v 3.8 (2.3-14.5) mmol; p < 0.05), and peak acid output (3.6 (1.2-12.0) v 7.6 (3.4-12.1) mmol; p < 0.05). The classic needle acupuncture, laser acupuncture, and sham acupuncture had no significant effect on gastric acid secretion. This study shows firstly that in healthy volunteers, only the versions of acupuncture using more pronounced stimulation (electroacupuncture, transcutaneous electrical nerve stimulation), but not those with only mild stimulation of the nerves (classic needle acupuncture, laser acupuncture), and secondly only acupuncture performed at defined points lead to significant reduction in gastric acid secretion. PMID:7926899

  1. Peptide 19-2.5 inhibits heparan sulfate-triggered inflammation in murine cardiomyocytes stimulated with human sepsis serum.

    PubMed

    Martin, Lukas; Schmitz, Susanne; De Santis, Rebecca; Doemming, Sabine; Haase, Hajo; Hoeger, Janine; Heinbockel, Lena; Brandenburg, Klaus; Marx, Gernot; Schuerholz, Tobias

    2015-01-01

    Myocardial dysfunction in sepsis has been linked to inflammation caused by pathogen-associated molecular patterns (PAMPs) as well as by host danger-associated molecular patterns (DAMPs). These include soluble heparan sulfate (HS), which triggers the devastating consequences of the pro-inflammatory cascades in severe sepsis and septic shock. Thus, there is increasing interest in the development of anti-infective agents, with effectiveness against both PAMPs and DAMPs. We hypothesized that a synthetic antimicrobial peptide (peptide 19-2.5) inhibits inflammatory response in murine cardiomyocytes (HL-1 cells) stimulated with PAMPs, DAMPs or serum from patients with septic shock by reduction and/or neutralization of soluble HS. In the current study, our data indicate that the treatment with peptide 19-2.5 decreases the inflammatory response in HL-1 cells stimulated with either PAMPs or DAMPs. Furthermore, our work shows that soluble HS in serum from patients with Gram-negative or Gram-positive septic shock induces a strong pro-inflammatory response in HL-1 cells, which can be effectively blocked by peptide 19-2.5. Based on these findings, peptide 19-2.5 is a novel anti-inflammatory agent interacting with both PAMPs and DAMPs, suggesting peptide 19-2.5 may have the potential for further development as a broad-spectrum anti-inflammatory agent in sepsis-induced myocardial inflammation and dysfunction. PMID:26024383

  2. Geochemical modelling of EGS fracture stimulation applying weak and strong acid treatments

    NASA Astrophysics Data System (ADS)

    Sigfusson, Bergur; Sif Pind Aradottir, Edda

    2015-04-01

    Engineered Geothermal systems (EGS) provide geothermal power by tapping into the Earth's deep geothermal resources that are otherwise not exploitable due to lack of water and fractures, location or rock type. EGS technologies have the potential to cost effectively produce large amounts of electricity almost anywhere in the world. The EGS technology creates permeability in the rock by hydro-fracturing the reservoir with cold water pumped into the first well (the injection well) at a high pressure. The second well (the production well) intersects the stimulated fracture system and returns the hot water to the surface where electricity can be generated. A significant technological hurdle is ensuring effective connection between the wells and the fracture system and to control the deep-rooted fractures (can exceed 5 000 m depth). A large area for heat transfer and sufficient mass flow needs to be ensured between wells without creating fast flowing paths in the fracture network. Maintaining flow through the fracture system can cause considerable energy penalty to the overall process. Therefore, chemical methods to maintain fractures and prevent scaling can be necessary to prevent excessive pressure build up in the re-injection wells of EGS systems. The effect of different acid treatments on the porosity development of selected rock types was simulated with the aid of the Petrasim interface to the Toughreact simulation code. The thermodynamic and kinetic database of Aradottir et al. (2014) was expanded to include new minerals and the most important fluoride bearing species involved in mineral reactions during acid stimulation of geothermal systems. A series of simulations with injection waters containing fluoric acid, hydrochloric acid and CO2 or mixtures thereof were then carried out and porosity development in the fracture system monitored. The periodic injection of weak acid mixtures into EGS systems may be cost effective in some isolated cases to prevent pressure

  3. Sirtuin inhibition attenuates the production of inflammatory cytokines in lipopolysaccharide-stimulated macrophages

    SciTech Connect

    Fernandes, Claudia A.; Fievez, Laurence; Neyrinck, Audrey M.; Delzenne, Nathalie M.; Bureau, Fabrice; Vanbever, Rita

    2012-04-20

    Highlights: Black-Right-Pointing-Pointer Lipopolysaccharide-stimulated macrophages were treated with cambinol and sirtinol. Black-Right-Pointing-Pointer Cambinol and sirtinol decreased lipopolysaccharide-induced cytokines. Black-Right-Pointing-Pointer Cambinol decreased NF-{kappa}B activity but had no impact on p38 MAPK activation. Black-Right-Pointing-Pointer Sirtuins are an interesting target for the treatment of inflammatory diseases. -- Abstract: In several inflammatory conditions such as rheumatoid arthritis or sepsis, the regulatory mechanisms of inflammation are inefficient and the excessive inflammatory response leads to damage to the host. Sirtuins are class III histone deacetylases that modulate the activity of several transcription factors that are implicated in immune responses. In this study, we evaluated the impact of sirtuin inhibition on the activation of lipopolysaccharide (LPS)-stimulated J774 macrophages by assessing the production of inflammatory cytokines. The pharmacologic inhibition of sirtuins decreased the production of tumour necrosis factor-alpha (TNF-{alpha}) interleukin 6 (IL-6) and Rantes. The reduction of cytokine production was associated with decreased nuclear factor kappa B (NF-{kappa}B) activity and inhibitor kappa B alpha (I{kappa}B{alpha}) phosphorylation while no impact was observed on the phosphorylation status of p38 mitogen-activated kinase (p38 MAPK). This work shows that sirtuin pharmacologic inhibitors are a promising tool for the treatment of inflammatory conditions.

  4. Enhancing and inhibiting stimulated Brillouin scattering in photonic integrated circuits (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Eggleton, Benjamin J.; Merklein, Moritz; Buettner, Thomas F. S.; Kabakova, Irina V.

    2015-09-01

    On-chip nonlinear optics is a thriving research field, which creates transformative opportunities for manipulating classical or quantum signals in small-footprint integrated devices. Since the length scales are short, nonlinear interactions need to be enhanced by exploiting materials with large nonlinearity in combination with high-Q resonators or slowlight structures. This, however, often results in simultaneous enhancement of competing Q2 nonlinear processes, which limit the efficiency and can cause signal distortion. Here, we exploit the frequency dependence of the optical density-of-states near the edge of a photonic bandgap to selectively enhance or inhibit nonlinear interactions on a chip. We demonstrate this concept for one of the strongest nonlinear effects, stimulated Brillouin scattering using a narrow-band one-dimensional photonic bandgap structure: a Bragg grating. The stimluated Brillouin scattering enhancement enables the generation of a 15-line Brillouin frequency comb. In the inhibition case, we achieve stimulated Brillouin scattering free operation at a power level twice the threshold

  5. Experimental Evidence of Short Light Pulse Amplification Using Strong-Coupling Stimulated Brillouin Scattering in the Pump Depletion Regime

    SciTech Connect

    Lancia, L.; Antici, P.; Marques, J.-R.; Nakatsutsumi, M.; Mancic, A.; Audebert, P.; Fuchs, J.; Riconda, C.; Weber, S.; Tikhonchuk, V. T.; Hueller, S.; Heron, A.

    2010-01-15

    The energy transfer from a long (3.5 ps) pump pulse to a short (400 fs) seed pulse due to stimulated Brillouin backscattering in the strong-coupling regime is investigated. The two pulses, both at the same wavelength of 1.057 {mu}m are quasicounterpropagating in a preformed underdense plasma. Relative amplification factors for the seed pulse of up to 32 are obtained. The maximum obtained amplified energy is 60 mJ. Simulations are in agreement with the experimental results and suggest paths for further improvement of the amplification scheme.

  6. Optimization of interaction conditions for efficient short laser pulse amplification by stimulated Brillouin scattering in the strongly coupled regime

    NASA Astrophysics Data System (ADS)

    Chiaramello, M.; Riconda, C.; Amiranoff, F.; Fuchs, J.; Grech, M.; Lancia, L.; Marquès, J.-R.; Vinci, T.; Weber, S.

    2016-07-01

    Plasma amplification of low energy, a short (˜100-500 fs) laser pulse by an energetic long (˜10 ps) pulse via strong coupling Stimulated Brillouin Backscattering is investigated with an extensive analysis of one-dimensional particle-in-cell simulations. Parameters relevant to nowadays experimental conditions are investigated. The obtained seed pulse spectra are analyzed as a function of the interaction conditions such as plasma profile, pulses delay, and seed or pulse duration. The factors affecting the amount of energy transferred are determined, and the competition between Brillouin-based amplification and parasitic Raman backscattering is analyzed, leading to the optimization of the interaction conditions.

  7. Experimental evidence of short light pulse amplification using strong-coupling stimulated brillouin scattering in the pump depletion regime.

    PubMed

    Lancia, L; Marquès, J-R; Nakatsutsumi, M; Riconda, C; Weber, S; Hüller, S; Mancić, A; Antici, P; Tikhonchuk, V T; Héron, A; Audebert, P; Fuchs, J

    2010-01-15

    The energy transfer from a long (3.5 ps) pump pulse to a short (400 fs) seed pulse due to stimulated Brillouin backscattering in the strong-coupling regime is investigated. The two pulses, both at the same wavelength of 1.057 microm are quasicounterpropagating in a preformed underdense plasma. Relative amplification factors for the seed pulse of up to 32 are obtained. The maximum obtained amplified energy is 60 mJ. Simulations are in agreement with the experimental results and suggest paths for further improvement of the amplification scheme. PMID:20366602

  8. N-Phenethyl caffeamide and photodamage: protecting skin by inhibiting type I procollagen degradation and stimulating collagen synthesis.

    PubMed

    Chiang, Hsiu-Mei; Chen, Chien-Wen; Lin, Tzu-Yu; Kuo, Yueh-Hsiung

    2014-10-01

    Skin is mainly damaged by genetic and environmental factors such as ultraviolet (UV) light and pollutants. UV light is a well-known factor that causes various types of skin damage and premature aging. Reactive oxygen species (ROS) are commonly involved in the pathogenesis of skin damage by activating the metalloproteinases that break down type I collagen. This study investigated the antioxidant and antiphotodamage activity and mechanisms of N-phenethyl caffeamide (K36) in human skin fibroblasts. The results indicated that K36 demonstrated strong 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, which dose-dependently reduced the production of UVB-induced intracellular ROS in human dermal fibroblasts. K36 prevented UVB-irradiation-induced type I collagen degradation by inhibiting the expression of matrix metalloproteins-1, -3, and -9 and the phosphorylation of mitogen-activated protein (MAP) kinases. Furthermore, K36 elevated collagen synthesis in skin fibroblasts by inhibiting UVB-induced Smad7 overexpression. K36 downregulated the expression of the transcription factor, activator protein-1 (AP-1). Our results indicated that K36 exhibited antioxidant properties and prevented skin collagen degradation caused by UV exposure and the stimulation of collagen synthesis, which suggests the potential use of K36 in preventing photodamage. PMID:25019243

  9. Varicella Viruses Inhibit Interferon-Stimulated JAK-STAT Signaling through Multiple Mechanisms

    PubMed Central

    Verweij, Marieke C.; Wellish, Mary; Whitmer, Travis; Malouli, Daniel; Lapel, Martin; Jonjić, Stipan; Haas, Juergen G.; DeFilippis, Victor R.; Mahalingam, Ravi; Früh, Klaus

    2015-01-01

    Varicella zoster virus (VZV) causes chickenpox in humans and, subsequently, establishes latency in the sensory ganglia from where it reactivates to cause herpes zoster. Infection of rhesus macaques with simian varicella virus (SVV) recapitulates VZV pathogenesis in humans thus representing a suitable animal model for VZV infection. While the type I interferon (IFN) response has been shown to affect VZV replication, the virus employs counter mechanisms to prevent the induction of anti-viral IFN stimulated genes (ISG). Here, we demonstrate that SVV inhibits type I IFN-activated signal transduction via the JAK-STAT pathway. SVV-infected rhesus fibroblasts were refractory to IFN stimulation displaying reduced protein levels of IRF9 and lacking STAT2 phosphorylation. Since previous work implicated involvement of the VZV immediate early gene product ORF63 in preventing ISG-induction we studied the role of SVV ORF63 in generating resistance to IFN treatment. Interestingly, SVV ORF63 did not affect STAT2 phosphorylation but caused IRF9 degradation in a proteasome-dependent manner, suggesting that SVV employs multiple mechanisms to counteract the effect of IFN. Control of SVV ORF63 protein levels via fusion to a dihydrofolate reductase (DHFR)-degradation domain additionally confirmed its requirement for viral replication. Our results also show a prominent reduction of IRF9 and inhibition of STAT2 phosphorylation in VZV-infected cells. In addition, cells expressing VZV ORF63 blocked IFN-stimulation and displayed reduced levels of the IRF9 protein. Taken together, our data suggest that varicella ORF63 prevents ISG-induction both directly via IRF9 degradation and indirectly via transcriptional control of viral proteins that interfere with STAT2 phosphorylation. SVV and VZV thus encode multiple viral gene products that tightly control IFN-induced anti-viral responses. PMID:25973608

  10. Benzyl isothiocyanate inhibits inflammasome activation in E. coli LPS-stimulated BV2 cells.

    PubMed

    Lee, Chang-Min; Lee, Dae-Sung; Jung, Won-Kyo; Yoo, Jong Su; Yim, Mi-Jin; Choi, Yung Hyun; Park, Saegwang; Seo, Su-Kil; Choi, Jung Sik; Lee, Young-Min; Park, Won Sun; Choi, Il-Whan

    2016-09-01

    Inflammasomes are multi-protein complexes that play a crucial role in innate immune responses. Benzyl isothiocyanate (BITC) is a naturally occurring compound found in cruciferous vegetables, and BITC exhibits potential as a chemopreventive agent. However, whether BITC exerts inflammasome-mediated regulatory effects on neuroinflammation is unknown. In this study, we examined the effects of BITC on inflammasome-mediated interleukin-1β (IL-1β) production in E. coli lipopolysaccharide (LPS)-stimulated BV2 microglial cells. IL-1β production is tightly regulated at the post-translational level through the inflammasoume. We measured the levels of IL-1β produced from the LPS-exposed BV2 microglial cells using enzyme-linked immunosorbent assays (ELISAs). The BITC regulatory mechanisms in inflammasome-mediated cellular signaling pathways were examined by RT-PCR, western blot analysis and electrophoretic mobility shift assays. BITC inhibited the secretion of IL-1β induced by LPS in the BV2 microglial cells. BITC inhibited inflammasome activation and NLR family, pyrin domain containing 3 (NLRP3)-mediated caspase-1 activation, and decreased the levels of inflammasome activation pro-inflammatory mediators, including mitochondrial reactive oxygen species (ROS) and adenosine triphosphate (ATP) secretion in the LPS-stimulated BV2 microglial cells. Furthermore, we demonstrated that nuclear factor-κB (NF-κB) activation induced by LPS was inhibited by BITC, which may contribute to the attenuated secretion of IL-1β. These BITC-mediated inhibitory effects on IL-1β expression may thus regulate neuroinflammation through the inflammasome-mediated signaling pathway. PMID:27430883

  11. Glycosyl glycerides from hydroponic Panax ginseng inhibited NO production in lipopolysaccharide-stimulated RAW264.7 cells

    PubMed Central

    Cha, Byeong-Ju; Park, Ji-Hae; Shrestha, Sabina; Baek, Nam-In; Lee, Sang Min; Lee, Tae Hoon; Kim, Jiyoung; Kim, Geum-Soog; Kim, Seung-Yu; Lee, Dae-Young

    2014-01-01

    Background Although the aerial parts of hydroponic Panax ginseng are reported to contain higher contents of total ginsenosides than those of roots, the isolation and identification of active metabolites from the aerial parts of hydroponic P. ginseng have not been carried out so far. Methods The aerial parts of hydroponic P. ginseng were applied on repeated silica gel and octadecylsilane columns to yield four glycosyl glycerides (Compounds 1–4), which were identified based on nuclear magnetic resonance, infrared, fast atom bombardment mass spectrometry, and gas chromatography/mass spectrometry data. Compounds 1–4 were evaluated for inhibition activity on NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Results and conclusion The glycosyl glycerides were identified to be (2S)-1-O-7(Z),10(Z),13(Z)-hexadecatrienoyl-3-O-β-d-galactopyranosyl-sn-glycerol (1), (2S)-1-O-linolenoyl-3-O-β-d-galactopyranosyl-sn-glycerol (2), (2S)-1-O-linolenoyl-2-O-linolenoyl-3-O-β-d-galactopyranosyl-sn-glycerol (3), and 2(S)-1-O-linoleoyl-2-O-linoleoyl-3-O-β-d-galactopyranosyl-sn-glycerol (4). Compounds 1 and 2 showed moderate inhibition activity on NO production in LPS-stimulated RAW264.7 cells [half maximal inhibitory concentration (IC50): 63.8 ± 6.4μM and 59.4 ± 6.8μM, respectively] without cytotoxicity at concentrations < 100μM, whereas Compounds 3 and 4 showed good inhibition effect (IC50: 7.7 ± 0.6μM and 8.0 ± 0.9μM, respectively) without cytotoxicity at concentrations < 20μM. All isolated compounds showed reduced messenger RNA (mRNA) expression of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α in LPS-induced macrophage cells with strong inhibition of mRNA activity observed for Compounds 3 and 4. PMID:26045690

  12. Apical ammonium inhibition of cAMP-stimulated secretion in T84 cells is bicarbonate dependent.

    PubMed

    Worrell, Roger T; Best, Alison; Crawford, Oscar R; Xu, Jie; Soleimani, Manoocher; Matthews, Jeffrey B

    2005-10-01

    Normal human colonic luminal (NH(4)(+)) concentration ([NH(4)(+)]) ranges from approximately 10 to 100 mM. However, the nature of the effects of NH(4)(+) on transport, as well as NH(4)(+) transport itself, in colonic epithelium is poorly understood. We elucidate here the effects of apical NH(4)(+) on cAMP-stimulated Cl(-) secretion in colonic T84 cells. In HEPES-buffered solutions, 10 mM apical NH(4)(+) had no significant effect on cAMP-stimulated current. In contrast, 10 mM apical NH(4)(+) reduced current within 5 min to 61 +/- 4% in the presence of 25 mM HCO(3)(-). Current inhibition was not simply due to an increase in extracellular K(+)-like cations, in that the current magnitude was 95 +/- 5% with 10 mM apical K(+) and 46 +/- 3% with 10 mM apical NH(4)(+) relative to that with 5 mM apical K(+). We previously demonstrated that inhibition of Cl(-) secretion by basolateral NH(4)(+) occurs in HCO(3)(-)-free conditions and exhibits anomalous mole fraction behavior. In contrast, apical NH(4)(+) inhibition of current in HCO(3)(-) buffer did not show anomalous mole fraction behavior and followed the absolute [NH(4)(+)] in K(+)-NH(4)(+) mixtures, where K(+) concentration + [NH(4)(+)] = 10 mM. The apical NH(4)(+) inhibitory effect was not prevented by 100 microM methazolamide, suggesting no role for apical carbonic anhydrase. However, apical NH(4)(+) inhibition of current was prevented by 10 min of pretreatment of the apical surface with 500 microM DIDS, 100 microM 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS), or 25 microM niflumic acid, suggesting a role for NH(4)(+) action through an apical anion exchanger. mRNA and protein for the apical anion exchangers SLC26A3 [downregulated in adenoma (DRA)] and SLC26A6 [putative anion transporter (PAT1)] were detected in T84 cells by RT-PCR and Northern and Western blots. DRA and PAT1 appear to associate with CFTR in the apical membrane. We conclude that the HCO(3)(-) dependence of apical NH(4)(+) inhibition of secretion is

  13. GABAergic activity in autism spectrum disorders: an investigation of cortical inhibition via transcranial magnetic stimulation.

    PubMed

    Enticott, Peter G; Kennedy, Hayley A; Rinehart, Nicole J; Tonge, Bruce J; Bradshaw, John L; Fitzgerald, Paul B

    2013-05-01

    Mounting evidence suggests a possible role for γ-aminobutyric acid (GABA) in the neuropathophysiology of autism spectrum disorders (ASD), but the extent of this impairment is unclear. A non-invasive, in vivo measure of GABA involves transcranial magnetic stimulation (TMS) of the primary motor cortex to probe cortical inhibition. Individuals diagnosed with ASD (high-functioning autism or Asperger's disorder) (n = 36 [28 male]; mean age: 26.00 years) and a group of healthy individuals (n = 34 [23 male]; mean age: 26.21 years) (matched for age, gender, and cognitive function) were administered motor cortical TMS paradigms putatively measuring activity at GABAA and GABAB receptors (i.e., short and long interval paired pulse TMS, cortical silent period). All cortical inhibition paradigms yielded no difference between ASD and control groups. There was, however, evidence for short interval cortical inhibition (SICI) deficits among those ASD participants who had experienced early language delay, suggesting that GABA may be implicated in an ASD subtype. The current findings do not support a broad role for GABA in the neuropathophysiology of ASD, but provide further indication that GABAA could be involved in ASD where there is a delay in language acquisition. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'. PMID:22727823

  14. Strong Specific Inhibition of UDP-glucuronosyltransferase 2B7 by Atractylenolide I and III.

    PubMed

    Zhang, Qian; Cao, Yun-Feng; Ran, Rui-Xue; Li, Rong-Shan; Wu, Xue; Dong, Pei-Pei; Zhang, Yan-Yan; Hu, Cui-Min; Wang, Wei-Ming

    2016-01-01

    Drug-metabolizing enzymes inhibition-based drug-drug interaction remains to be the key limiting factor for the research and development of efficient herbal components to become clinical drugs. The present study aims to determine the inhibition of uridine 5'-diphospho-glucuronosyltransferases (UGTs) isoforms by two important efficient herbal ingredients isolated from Atractylodes macrocephala Koidz, atractylenolide I and III. In vitro recombinant UGTs-catalysed glucuronidation of 4-methylumbelliferone was used to determine the inhibition capability and kinetics of atractylenolide I and III towards UGT2B7, and in silico docking method was employed to explain the possible mechanism. Atractylenolide I and III exhibited specific inhibition towards UGT2B7, with negligible influence towards other UGT isoforms. Atractylenolide I exerted stronger inhibition potential than atractylenolide III towards UGT2B7, which is attributed to the different hydrogen bonds and hydrophobic interactions. Inhibition kinetic analysis was performed for the inhibition of atractylenolide I towards UGT2B7. Inhibition kinetic determination showed that atractylenolide I competitively inhibited UGT2B7, and inhibition kinetic parameter (Ki) was calculated to be 6.4 μM. In combination of the maximum plasma concentration of atractylenolide I after oral administration of 50 mg/kg atractylenolide I, the area under the plasma concentration-time curve ration AUCi /AUC was calculated to be 1.17, indicating the highly possible drug-drug interaction between atractylenolide I and drugs mainly undergoing UGT2B7-catalysed metabolism. PMID:26536846

  15. Proteinase-activated receptor-2 mediated inhibition of TNFα-stimulated JNK activation — A novel paradigm for Gq/11 linked GPCRs

    PubMed Central

    McIntosh, Kathryn; Cunningham, Margaret R.; Cadalbert, Laurence; Lockhart, John; Boyd, Gary; Ferrell, W.R.; Plevin, Robin

    2010-01-01

    In this study we examined the potential for PAR2 and TNFα to synergise at the level of MAP kinase signalling in PAR2 expressing NCTC2544 cells. However, to our surprise we found that activation of PAR2 by trypsin or the specific activating peptide SLIGKV-OH strongly inhibited both the phosphorylation and activity of JNK. In contrast neither p38 MAP kinase nor ERK activation was affected although TNFα stimulated IκBα loss was partially reversed. The inhibitory effect was not observed in parental cells nor in cells expressing PAR4, however inhibition was reversed by pre-incubation with the novel PAR2 antagonist K14585, suggesting that the effect is specific for PAR2 activation. SLIGKV-OH was found to be more potent in inhibiting TNFα-induced JNK activation than in stimulating JNK alone, suggesting agonist-directed signalling. The PKC activator PMA, also mimicked the inhibitory effect of SLIGKV-OH, and the effects of both agents were reversed by pre-treatment with the PKC inhibitor, GF109203X. Furthermore, incubation with the novel Gq/11 inhibitor YM25480 also reversed PAR2 mediated inhibition. Activation of PAR2 was found to disrupt TNFR1 binding to RIP and TRADD and this was reversed by both GF109203X and YM25480. A similar mode of inhibition observed in HUVECs through PAR2 or P2Y2 receptors demonstrates the potential of a novel paradigm for GPCRs linked to Gq/11, in mediating inhibition of TNFα-stimulated JNK activation. This has important implications in assessing the role of GPCRs in inflammation and other conditions. PMID:19781631

  16. Cardioprotective Actions of TGFβRI Inhibition Through Stimulating Autocrine/Paracrine of Survivin and Inhibiting Wnt in Cardiac Progenitors.

    PubMed

    Ho, Yu-Sian; Tsai, Wan-Hsuan; Lin, Fen-Chiung; Huang, Wei-Pang; Lin, Lung-Chun; Wu, Sean M; Liu, Yu-Ru; Chen, Wen-Pin

    2016-02-01

    Heart failure due to myocardial infarction (MI) is a major cause of morbidity and mortality in the world. We found previously that A83-01, a TGFβRI inhibitor, could facilitate cardiac repair in post-MI mice and induce the expansion of a Nkx2.5 + cardiomyoblast population. This study aimed to investigate the key autocrine/paracrine factors regulated by A83-01 in the injured heart and the mechanism of cardioprotection by this molecule. Using a previously described transgenic Nkx2.5 enhancer-green fluorescent protein (GFP) reporter mice, we isolated cardiac progenitor cells (CPC) including Nkx2.5-GFP + (Nkx2.5+), sca1+, and Nkx2.5+/sca1 + cells. A83-01 was found to induce proliferation of these three subpopulations mainly through increasing Birc5 expression in the MEK/ERK-dependent pathway. Survivin, encoded by Birc5, could also directly proliferate Nkx2.5 + cells and enhance cultured cardiomyocytes viability. A83-01 could also reverse the downregulation of Birc5 in postinjured mice hearts (n = 6) to expand CPCs. Moreover, the increased Wnt3a in postinjured hearts could decrease CPCs, which could be reversed by A83-01 via inhibiting Fzd6 and Wnt1-induced signaling protein 1 expressions in CPCs. Next, we used inducible αMHC-cre/mTmG mice to label cardiomyocytes with GFP and nonmyocytes with RFP. We found A83-01 preserved more GFP + myocytes (68.6% ± 3.1% vs. 80.9% ± 3.0%; p < .05, n = 6) and fewer renewed RFP + myocytes (0.026% ± 0.005% vs. 0.062% ± 0.008%; p < .05, n = 6) in parallel with less cardiac fibrosis in isoprenaline-injected mice treated with A83-01. TGFβRI inhibition in an injured adult heart could both stimulate the autocrine/paracrine activity of survivin and inhibit Wnt in CPCs to mediate cardioprotection and improve cardiac function. PMID:26418219

  17. Plant extracts from Cameroonian medicinal plants strongly inhibit hepatitis C virus infection in vitro

    PubMed Central

    Galani, Borris R. T.; Sahuc, Marie-Emmanuelle; Njayou, Frederic N.; Deloison, Gaspard; Mkounga, Pierre; Feudjou, William F.; Brodin, Priscille; Rouillé, Yves; Nkengfack, Augustin E.; Moundipa, Paul Fewou; Séron, Karin

    2015-01-01

    According to some recent studies, Cameroon is one of the sub-Saharan African countries most affected by hepatitis C, with low access to the standard therapy based on the combination of pegylated interferon and ribavirin. A first ethnobotanical survey, conducted in the Western region of Cameroon, reported the use of several medicinal plants in traditional medicine for the healing of liver-related disorders. Crude organic extracts of five plants surveyed were prepared and their effect against hepatitis C virus (HCV) infection investigated. The HCV JFH1 strain cell culture system HCVcc was used. The antiviral activity was quantified by immunofluorescent labeling of HCV E1 envelope protein at 30 h post-infection in the presence of the plant extracts. Active compounds were then tested in time course infection experiments. Dose-response and cellular toxicity assays were also determined. Three extracts, methanol extracts from roots of Trichilia dregeana, stems of Detarium microcarpum and leaves of Phragmanthera capitata, showed anti-HCV activity, with half-maximal inhibitory concentration of 16.16, 1.42, and 13.17 μg/mL, respectively. Huh-7 cells were incubated with the extracts for 72 h and it appears that T. dregeana extract is not toxic up to 200 μg/mL, D. microcarpum up to 100 μg/mL and P. capitata up to 800 μg/mL. All the three extracts showed a strong inhibition of HCV entry and no effect on replication or secretion. Taken together, these results showed that extracts from Cameroonian medicinal plants are promising sources of anti-HCV agents. PMID:26029203

  18. Inhibition of bladder overactivity by duloxetine in combination with foot stimulation or WAY-100635 treatment in cats.

    PubMed

    Schwen, Zeyad; Matsuta, Yosuke; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2013-12-15

    The purpose of this study was to determine whether duloxetine [a serotonin (5-HT)-norepinephrine reuptake inhibitor] combined with transcutaneous foot stimulation or WAY-100635 (a 5-HT1A antagonist) can enhance inhibition of bladder overactivity in cats. Cystometrograms were performed on eight cats under α-chloralose anesthesia by infusing saline and then 0.25% acetic acid (AA) to induce bladder overactivity. To inhibit bladder overactivity, foot stimulation (5 Hz) was applied via transcutaneous pad electrodes to the right hindfoot at two and four times the threshold intensity for inducing a toe twitch. Duloxetine (0.003-3 mg/kg) was administered intravenously to determine the effect of combination treatment. After the 3 mg/kg dose of duloxetine, WAY-100635 (0.5 mg/kg) was given intravenously. AA irritation significantly (P < 0.0001) reduced bladder capacity to 42.7 ± 7.4% of the saline control capacity. Foot stimulation alone at both two and four times the threshold intensity significantly (P < 0.0001) inhibited bladder overactivity and increased bladder capacity to 66.7 ± 6.3% and 85.7 ± 6.5% of the saline control, respectively. Duloxetine alone dose dependently inhibited bladder overactivity and completely restored bladder capacity to the saline control (109 ± 15.5%) at 3 mg/kg. Although duloxetine combined with foot stimulation did not further enhance inhibition, WAY-100635 (0.5 mg/kg) given after 3 mg/kg duloxetine further increased (P = 0.008) bladder capacity to 162.2 ± 22.5% of the saline control. Although duloxetine and foot stimulation independently inhibited bladder overactivity, combined treatment did not enhance inhibition. Duloxetine combined with WAY-100635, however, synergistically enhanced bladder inhibition, indicating a potential novel treatment for overactive bladder if duloxetine is combined with a 5-HT1A receptor antagonist drug. PMID:24154699

  19. [Effects of psychotropic drugs on lateral hypothalamic self-stimulation behavior in rats: correlation between self-stimulation behavior inhibition and striatal dopaminergic blockade by neuroleptic drugs].

    PubMed

    Fukuda, T; Tsumagari, T

    1984-06-01

    The effects of neuroleptic drugs on self-stimulation behavior were investigated in rats with electrodes chronically implanted in the lateral hypothalamus. Except for sulpiride and carpipramine, the neuroleptic drugs chlorpromazine, thioridazine, perphenazine, haloperidol, floropipamide, pimozide, clocapramine and oxypertine all suppressed self-stimulation behavior dose-dependently. The anti-anxiety drugs chlordiazepoxide, diazepam, clotiazepam and etizolam facilitated this behavior. The antidepressant drugs imipramine and amitriptyline suppressed this behavior slightly at the dose of 40 mg/kg. The alpha-antagonist phenoxybenzamine also suppressed this behavior, but the slope of its dose-response curve was gentle compared with those of the neuroleptic drugs. The inhibition produced by the neuroleptic drugs is considered to be mediated primarily at the dopaminergic receptors. Turning behavior induced by methamphetamine in rats with unilateral 6-hydroxydopamine lesions of the caudate nucleus was used to assess the striatal dopaminergic blocking potency of the neuroleptic drugs. No correlation was found between the ED50 values for the turning behavior inhibition and the ED50 values for the self-stimulation behavior inhibition produced by these drugs, so the dopaminergic receptors in the striatum are apparently not involved in the mediation of self-stimulation behavior. PMID:6149172

  20. Enkephalin inhibition of angiotensin-stimulated release of oxytocin and vasopressin

    NASA Technical Reports Server (NTRS)

    Keil, L. C.; Chee, O.; Rosella-Dampman, L. M.; Emmert, S.; Summy-Long, J. Y.

    1984-01-01

    The effect of intracerebroventricular (ICV) pretreatment with 100 ng/5 microliter leucine(5)-enkephalin (LE) on the increase in plasma oxytocin (OT) and vasopressin (VP) caused by ICV injection of 10, 50, or 100 ng/5 microliter of angiotensin II (AII) is investigated experimentally in conscious adult male Sprague-Dawley rats; the effects of water-deprivation dehydration and lactation/suckling (in female rats) are also studied. An OT radioimmunoassay (RIA) with a sensitivity of 800 fg/ml (described in detail) and the VP RIA technique of Keil and Severs (1977) are employed. Administration of AII or dehydration for 48 or 72 h cause a significant increase in OT and VP without affecting the ratio, while lactation and suckling increase OT only. LE pretreatment inhibits significantly but does not suppress the AII-stimulated OT-VP response.

  1. Interhemispheric Inhibition Induced by Transcranial Magnetic Stimulation Over Primary Sensory Cortex

    PubMed Central

    Iwata, Yasuyuki; Jono, Yasutomo; Mizusawa, Hiroki; Kinoshita, Atsushi; Hiraoka, Koichi

    2016-01-01

    The present study investigated whether the long-interval interhemispheric inhibition (LIHI) is induced by the transcranial magnetic stimulation over the primary sensory area (S1-TMS) without activation of the conditioning side of the primary motor area (M1) contributing to the contralateral motor evoked potential (MEP), whether the S1-TMS-induced LIHI is dependent on the status of the S1 modulated by the tactile input, and whether the pathways mediating the LIHI are different from those mediating the M1-TMS-induced LIHI. In order to give the TMS over the S1 without eliciting the MEP, the intensity of the S1-TMS was adjusted to be the sub-motor-threshold level and the trials with the MEP response elicited by the S1-TMS were discarded online. The LIHI was induced by the S1-TMS given 40 ms before the test TMS in the participants with the attenuation of the tactile perception of the digit stimulation (TPDS) induced by the S1-TMS, indicating that the LIHI is induced by the S1-TMS without activation of the conditioning side of the M1 contributing to the contralateral MEP in the participants in which the pathways mediating the TPDS is sensitive to the S1-TMS. The S1-TMS-induced LIHI was positively correlated with the attenuation of the TPDS induced by the S1-TMS, indicating that the S1-TMS-induced LIHI is dependent on the effect of the S1-TMS on the pathways mediating the TPDS at the S1. In another experiment, the effect of the digit stimulation given before the conditioning TMS on the S1- or M1-TMS-induced LIHI was examined. The digit stimulation produces tactile input to the S1 causing change in the status of the S1. The S1-TMS-induced LIHI was enhanced when the S1-TMS was given in the period in which the tactile afferent volley produced by the digit stimulation just arrived at the S1, while the LIHI induced by above-motor-threshold TMS over the contralateral M1 was not enhanced by the tactile input. Thus, the S1-TMS-induced LIHI is dependent on the status of the S1

  2. The SCFA butyrate stimulates the epithelial production of retinoic acid via inhibition of epithelial HDAC.

    PubMed

    Schilderink, Ronald; Verseijden, Caroline; Seppen, Jurgen; Muncan, Vanesa; van den Brink, Gijs R; Lambers, Tim T; van Tol, Eric A; de Jonge, Wouter J

    2016-06-01

    In the intestinal mucosa, retinoic acid (RA) is a critical signaling molecule. RA is derived from dietary vitamin A (retinol) through conversion by aldehyde dehydrogenases (aldh). Reduced levels of short-chain fatty acids (SCFAs) are associated with pathological microbial dysbiosis, inflammatory disease, and allergy. We hypothesized that SCFAs contribute to mucosal homeostasis by enhancing RA production in intestinal epithelia. With the use of human and mouse epithelial cell lines and primary enteroids, we studied the effect of SCFAs on the production of RA. Functional RA conversion was analyzed by Adlefluor activity assays. Butyrate (0-20 mM), in contrast to other SCFAs, dose dependently induced aldh1a1 or aldh1a3 transcript expression and increased RA conversion in human and mouse epithelial cells. Epithelial cell line data were replicated in intestinal organoids. In these organoids, butyrate (2-5 mM) upregulated aldh1a3 expression (36-fold over control), whereas aldh1a1 was not significantly affected. Butyrate enhanced maturation markers (Mucin-2 and villin) but did not consistently affect stemness markers or other Wnt target genes (lgr5, olfm4, ascl2, cdkn1). In enteroids, the stimulation of RA production by SCFA was mimicked by inhibitors of histone deacetylase 3 (HDAC3) but not by HDAC1/2 inhibitors nor by agonists of butyrate receptors G-protein-coupled receptor (GPR)43 or GPR109A, indicating that butyrate stimulates RA production via HDAC3 inhibition. We conclude that the SCFA butyrate inhibits HDAC3 and thereby supports epithelial RA production. PMID:27151945

  3. Moutan Cortex Radicis inhibits inflammatory changes of gene expression in lipopolysaccharide-stimulated gingival fibroblasts.

    PubMed

    Yun, Cheol-Sang; Choi, Yeong-Gon; Jeong, Mi-Young; Lee, Je-Hyun; Lim, Sabina

    2013-07-01

    Moutan Cortex Radicis (MCR), the root bark of Paeonia suffruticosa Andrews (Paeoniaceae), is found in the traditional Chinese medicinal formulae which were used to treat periodontal diseases. This study investigated the changes in gene expression by MCR treatment when stimulated with lipopolysaccharide (LPS) in cultured human gingival fibroblasts (HGFs). A genome-wide expression GeneChip was used for the gene array analysis, and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis was also performed to confirm the gene expression. It was shown that 42 of the 643 genes up-regulated by LPS, when compared to the control, were down-regulated by the MCR treatment. Of these 42 genes, the inflammation and immune response-related genes were especially noted, which indicates that MCR inhibits the induction of inflammation by LPS stimulation. In addition, 33 of the 519 genes down-regulated by LPS, when compared to the control, were up-regulated by the MCR treatment. The expression patterns of some representative genes by real-time RT-PCR correlated with those of the genes shown in the microarray. In addition, the MCR extract contained paeonol and paeoniflorin, which are known to have the anti-inflammatory effect as the major phenolic components of MCR. This study showed that the MCR extract could comprehensively inhibit a wide variety of activations of inflammation-related genes, which may be due to paeonol and paeoniflorin. It is, thus, suggested that MCR may be applied to alleviate the inflammation of periodontal diseases. PMID:23086154

  4. Activation and inhibition of retinal ganglion cells in response to epiretinal electrical stimulation: a computational modelling study

    NASA Astrophysics Data System (ADS)

    Abramian, Miganoosh; Lovell, Nigel H.; Morley, John W.; Suaning, Gregg J.; Dokos, Socrates

    2015-02-01

    Objective. Retinal prosthetic devices aim to restore sight in visually impaired people by means of electrical stimulation of surviving retinal ganglion cells (RGCs). This modelling study aims to demonstrate that RGC inhibition caused by high-intensity cathodic pulses greatly influences their responses to epiretinal electrical stimulation and to investigate the impact of this inhibition on spatial activation profiles as well as their implications for retinal prosthetic device design. Another aim is to take advantage of this inhibition to reduce axonal activation in the nerve fibre layer. Approach. A three-dimensional finite-element model of epiretinal electrical stimulation was utilized to obtain RGC activation and inhibition threshold profiles for a range of parameters. Main results. RGC activation and inhibition thresholds were highly dependent on cell and stimulus parameters. Activation thresholds were 1.5, 3.4 and 11.3 μA for monopolar electrodes with 5, 20 and 50 μm radii, respectively. Inhibition to activation threshold ratios were mostly within the range 2-10. Inhibition significantly altered spatial patterns of RGC activation. With concentric electrodes and appropriately high levels of stimulus amplitudes, activation of passing axons was greatly reduced. Significance. RGC inhibition significantly impacts their spatial activation profiles, and therefore it most likely influences patterns of perceived phosphenes induced by retinal prosthetic devices. Thus this inhibition should be taken into account in future studies concerning retinal prosthesis development. It might be possible to utilize this inhibitory effect to bypass activation of passing axons and selectively stimulate RGCs near their somas and dendrites to achieve more localized phosphenes.

  5. Differential regulation of human platelet responses by cGMP inhibited and stimulated cAMP phosphodiesterases.

    PubMed

    Manns, J M; Brenna, K J; Colman, R W; Sheth, S B

    2002-05-01

    Platelets contain two cAMP phosphodiesterases (PDEs) which regulate intracellular cAMP levels, cGMP-inhibited cAMP PDE (PDE3A) and cGMP-stimulated PDE (PDE2A). Using the PDE3 inhibitor, milrinone and the PDE2 inhibitor, erythro-9-(2-hydroxyl-3-nonyl)adenine (EHNA), we have explored the contribution of each PDE to the regulation of platelet function. Inhibition of PDE2 resulted in higher levels of intracellular cAMP than inhibition of PDE3A suggesting this PDE may be the more important regulator of cAMP in human platelets. However, a concentration-dependent inhibition of agonist-induced aggregation was observed with milrinone while little effect was seen with EHNA. In addition, we observed a concentration-dependent inhibition in the increase of intracellular Ca2+ with PDE3 inhibition and significantly less with PDE2 inhibition. PDE3 inhibition also resulted in a concentration-dependent increase in cAMP-mediated phosphorylation of the vasodilator-stimulated phospho-protein (VASP) whereas there was no significant increase with PDE2 inhibition. In each of these experiments, synergism was noted with the combination of milrinone and EHNA. These results suggest that cAMP pools may be localized and the various PDEs regulate specific pools. These data also suggest that inhibitors of PDE3A may be more effective antiplatelet agents. PMID:12038792

  6. Butylated Hydroxyanisole Stimulates Heme Oxygenase-1 Gene Expression and Inhibits Neointima Formation in Rat Arteries

    PubMed Central

    Liu, Xiao-ming; Azam, Mohammed A.; Peyton, Kelly J.; Ensenat, Diana; Keswani, Amit N.; Wang, Hong; Durante, William

    2007-01-01

    Objective Butylated hydroxyanisole (BHA) is a synthetic phenolic compound that is a potent inducer of phase II genes. Since heme oxygenase-1 (HO-1) is a vasoprotective protein that is upregulated by phase II inducers, the present study examined the effects of BHA on HO-1 gene expression and vascular smooth muscle cell proliferation. Methods The regulation of HO-1 gene expression and vascular cell growth by BHA was studied in cultured rat aortic smooth muscle cells and in balloon injured rat carotid arteries. Results Treatment of cultured smooth muscle cells with BHA stimulated the expression of HO-1 protein, mRNA and promoter activity in a time- and concentration-dependent manner. BHA-mediated HO-1 expression was dependent on the activation of NF-E2-related factor-2 by p38 mitogen-activated protein kinase. BHA also inhibited cell cycle progression and DNA synthesis in a HO-1-dependent manner. In addition, the local perivascular delivery of BHA immediately after arterial injury of rat carotid arteries induced HO-1 protein expression and markedly attenuated neointima formation. Conclusions These studies demonstrate that BHA stimulates HO-1 gene expression in vascular smooth muscle cells, and that the induction of HO-1 contributes to the antiproliferative actions of this phenolic antioxidant. BHA represents a potentially novel therapeutic agent in treating or preventing vasculoproliferative disease. PMID:17320844

  7. Cortical electroconvulsive stimulation alleviates breeding-induced prepulse inhibition deficit in rats.

    PubMed

    John, Nadine; Theilmann, Wiebke; Frieling, Helge; Krauss, Joachim K; Alam, Mesbah; Schwabe, Kerstin; Brandt, Claudia

    2016-01-01

    In patients with medical-refractory schizophrenia electroconvulsive therapy (ECT), i.e., the induction of therapeutic seizures via cortical surface electrodes, is effectively used. Electroconvulsive stimulation (ECS) in rodents simulates ECT in humans and is applied to investigate the mechanisms underlying this treatment. Experimentally-induced reduced prepulse inhibition (PPI) of the acoustic startle response (ASR), i.e., the reduction of the startle response to an intense acoustic stimulus when this stimulus is shortly preceded by a weaker not-startling stimulus, serves as an endophenotype for neuropsychiatric disorders that are accompanied by disturbed sensorimotor gating, such as schizophrenia. Here we used rats selectively bred for high and low PPI to evaluate whether bifrontal cortical ECS would affect PPI. For this purpose, cortical screw electrodes were stereotactically implanted above the frontal cortex. After recovery ECS was applied for five consecutive days with stimuli of 1 ms pulse-width, 100 pulses/s, 1 s duration, ranging from 5.5 mA to 10 mA. PPI of ASR was measured one day before ECS, and on days 1, 7, and 14 after the last ECS. In rats with breeding-induced low PPI ECS increased PPI one week after stimulation. In contrast, ECS decreased PPI in rats with high PPI on the first day after stimulation. The reaction to the startle impulse was reduced by ECS without difference between groups. This work provides evidence that rats with breeding-induced high or low PPI could be used to further investigate the underlying mechanisms of ECT in neuropsychiatric disorders with disturbed sensorimotor gating like schizophrenia. PMID:26476178

  8. Cyclic di-GMP stimulates biofilm formation and inhibits virulence of Francisella novicida.

    PubMed

    Zogaj, Xhavit; Wyatt, Geoff C; Klose, Karl E

    2012-12-01

    Francisella tularensis is a gram-negative bacterium that is highly virulent in humans, causing the disease tularemia. F. novicida is closely related to F. tularensis and exhibits high virulence in mice, but it is avirulent in healthy humans. An F. novicida-specific gene cluster (FTN0451 to FTN0456) encodes two proteins with diguanylate cyclase (DGC) and phosphodiesterase (PDE) domains that modulate the synthesis and degradation of cyclic di-GMP (cdGMP). No DGC- or PDE-encoding protein genes are present in the F. tularensis genome. F. novicida strains lacking either the two DGC/PDE genes (cdgA and cdgB) or the entire gene cluster (strain KKF457) are defective for biofilm formation. In addition, expression of CdgB or a heterologous DGC in strain KKF457 stimulated F. novicida biofilms, even in a strain lacking the biofilm regulator QseB. Genetic evidence suggests that CdgA is predominantly a PDE, while CdgB is predominantly a DGC. The F. novicida qseB strain showed reduced cdgA and cdgB transcript levels, demonstrating an F. novicida biofilm signaling cascade that controls cdGMP levels. Interestingly, KKF457 with elevated cdGMP levels exhibited a decrease in intramacrophage replication and virulence in mice, as well as increased growth yields and biofilm formation in vitro. Microarray analyses revealed that cdGMP stimulated the transcription of a chitinase (ChiB) known to contribute to biofilm formation. Our results indicate that elevated cdGMP in F. novicida stimulates biofilm formation and inhibits virulence. We suggest that differences in human virulence between F. novicida and F. tularensis may be due in part to the absence of cdGMP signaling in F. tularensis. PMID:22988021

  9. Cyclic Di-GMP Stimulates Biofilm Formation and Inhibits Virulence of Francisella novicida

    PubMed Central

    Zogaj, Xhavit; Wyatt, Geoff C.

    2012-01-01

    Francisella tularensis is a Gram-negative bacterium that is highly virulent in humans, causing the disease tularemia. F. novicida is closely related to F. tularensis and exhibits high virulence in mice, but it is avirulent in healthy humans. An F. novicida-specific gene cluster (FTN0451 to FTN0456) encodes two proteins with diguanylate cyclase (DGC) and phosphodiesterase (PDE) domains that modulate the synthesis and degradation of cyclic di-GMP (cdGMP). No DGC- or PDE-encoding protein genes are present in the F. tularensis genome. F. novicida strains lacking either the two DGC/PDE genes (cdgA and cdgB) or the entire gene cluster (strain KKF457) are defective for biofilm formation. In addition, expression of CdgB or a heterologous DGC in strain KKF457 stimulated F. novicida biofilms, even in a strain lacking the biofilm regulator QseB. Genetic evidence suggests that CdgA is predominantly a PDE, while CdgB is predominantly a DGC. The F. novicida qseB strain showed reduced cdgA and cdgB transcript levels, demonstrating an F. novicida biofilm signaling cascade that controls cdGMP levels. Interestingly, KKF457 with elevated cdGMP levels exhibited a decrease in intramacrophage replication and virulence in mice, as well as increased growth yields and biofilm formation in vitro. Microarray analyses revealed that cdGMP stimulated the transcription of a chitinase (ChiB) known to contribute to biofilm formation. Our results indicate that elevated cdGMP in F. novicida stimulates biofilm formation and inhibits virulence. We suggest that differences in human virulence between F. novicida and F. tularensis may be due in part to the absence of cdGMP signaling in F. tularensis. PMID:22988021

  10. Spinal inhibition of phrenic motoneurones by stimulation of afferents from leg muscle in the cat: blockade by strychnine.

    PubMed

    Eldridge, F L; Millhorn, D E; Waldrop, T

    1987-08-01

    1. Phrenic nerve responses to stimulation of calf muscle receptors or their afferents were studied in paralysed high (C1) spinal cats whose phrenic nerve activity was evoked by activation of the intercostal-to-phrenic reflex. End-tidal PCO2 was maintained at a constant level by means of a servo-controlled ventilator. 2. Physical stimulation of calf muscles or electrical stimulation of the tibial nerve uniformly caused inhibition of phrenic activity evoked by facilitatory conditioning stimuli. The degree of inhibition gradually decreased as muscle stimulation continued, and there was a post-stimulus augmentation of phrenic activity. 3. Pre-treatment with subconvulsive doses of strychnine, an antagonist of the neurotransmitter glycine, partially or completely blocked the inhibitory effects on phrenic activity of muscle-afferent stimulation. The blockade was reversible with time. 4. Pre-treatment with a subconvulsive dose of bicuculline, an antagonist of the neurotransmitter gamma-aminobutyric acid (GABA), had no effect on the inhibitory mechanism. 5. We conclude that glycine is an important transmitter of the inhibition of phrenic motoneurones induced by muscle-afferent stimulation, but that GABA is not involved in this inhibitory mechanism. PMID:3681723

  11. Hyperoside, a flavonoid compound, inhibits proliferation and stimulates osteogenic differentiation of human osteosarcoma cells.

    PubMed

    Zhang, Ning; Ying, Mei-Dan; Wu, Yong-Ping; Zhou, Zhi-Hong; Ye, Zhao-Ming; Li, Hang; Lin, Ding-Sheng

    2014-01-01

    Osteosarcoma, one of the most common malignant bone tumours, is generally considered a differentiation disease caused by genetic and epigenetic disruptions in the terminal differentiation of osteoblasts. Novel therapies based on the non-cytotoxic induction of cell differentiation-responsive pathways could represent a significant advance in treating osteosarcoma; however, effective pharmaceuticals to induce differentiation are lacking. In the present study, we investigated the effect of hyperoside, a flavonoid compound, on the osteoblastic differentiation of U2OS and MG63 osteosarcoma cells in vitro. Our results demonstrated that hyperoside inhibits the proliferation of osteosarcoma cells by inducing G0/G1 arrest in the cell cycle, without causing obvious cell death. Cell migration assay further suggested that hyperoside could inhibit the invasion potential of osteosarcoma cells. Additionally, osteopontin and runt-related transcription factor 2 protein levels and osteocalcin activation were upregulated dramatically in hyperoside-treated osteosarcoma cells, suggesting that hyperoside may stimulates osteoblastic differentiation in osteosarcoma cells. This differentiation was accompanied by the activation of transforming growth factor (TGF)-β and bone morphogenetic protein-2, suggesting that the hyperoside-induced differentiation involves the TGF-β signalling pathway. To our knowledge, this study is the first to evaluate the differentiation effect of hyperoside in osteosarcoma cells and assess the possible potential for hyperoside treatment as a future therapeutic approach for osteosarcoma differentiation therapy. PMID:24983940

  12. Methotrexate inhibits neutrophil function by stimulating adenosine release from connective tissue cells

    SciTech Connect

    Cronstein, B.N.; Eberle, M.A.; Levin, R.I. ); Gruber, H.E. )

    1991-03-15

    Although commonly used to control a variety of inflammatory diseases, the mechanism of action of a low dose of methotrexate remains a mystery. Methotrexate accumulates intracellularly where it may interfere with purine metabolism. Therefore, the authors determined whether a 48-hr pretreatment with methotrexate affected adenosine release from ({sup 14}C)adenine-labeled human fibroblasts and umbilical vein endothelial cells. Methotrexate significantly increased adenosine release by fibroblasts. The effect of methotrexate on adenosine release was not due to cytotoxicity since cells treated with maximal concentrations of methotrexate took up ({sup 14}C)adenine and released {sup 14}C-labeled purine (a measure of cell injury) in a manner identical to control cells. Methotrexate treatment of fibroblasts dramatically inhibited adherence to fibroblasts by both unstimulated neutrophils and stimulated neutrophils. One hypothesis that explains the effect of methotrexate on adenosine release is that, by inhibition of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase, methotrexate induces the accumulation of AICAR, the nucleoside precursor of which has previously been shown to cause adenosine release from ischemic cardiac tissue. The observation that the antiinflammatory actions of methotrexate are due to the capacity of methotrexate to induce adenosine release may form the basis for the development of an additional class of antiinflammatory drugs.

  13. Angiotensin II-stimulated secretion of arginine vasopressin is inhibited by atrial natriuretic peptide in humans.

    PubMed

    Matsukawa, Toshiyoshi; Miyamoto, Takenori

    2011-03-01

    We investigated the effect of the intravenous infusion of atrial natriuretic peptide (ANP) on the response of plasma arginine vasopressin (AVP) levels to intravenous infusion of angiotensin II (ANG II) in healthy individuals. Intravenous infusion of ANP (10 ng·kg(-1)·min(-1)) slightly but significantly decreased plasma AVP levels, while intravenous infusion of ANG II (10 ng·kg(-1)·min(-1)) resulted in slightly increased plasma AVP levels. ANG II infused significant elevations in arterial blood pressure and central venous pressure (CVP). Because the elevation in blood pressure could have potentially inhibited AVP secretion via baroreceptor reflexes, the effect of ANG II on blood pressure was attenuated by the simultaneous infusion of nitroprusside. ANG II alone produced a remarkable increase in plasma AVP levels when infused with nitroprusside, whereas the simultaneous ANP intravenous infusion (10 ng·kg(-1)·min(-1)) abolished the increase in plasma AVP levels induced by ANG II when blood pressure elevation was attenuated by nitroprusside. Thus, ANG II increased AVP secretion and ANP inhibited not only basal AVP secretion but also ANG II-stimulated AVP secretion in humans. These findings support the hypothesis that circulating ANP modulates AVP secretion, in part, by antagonizing the action of circulating ANG II. PMID:21123762

  14. Aqueous extract of Abutilon indicum Sweet inhibits glucose absorption and stimulates insulin secretion in rodents.

    PubMed

    Krisanapun, Chutwadee; Peungvicha, Penchom; Temsiririrkkul, Rungravi; Wongkrajang, Yuvadee

    2009-08-01

    The objective of this study was to evaluate the antidiabetic effects of the aqueous extract derived from the Thai Abutilon indicum Sweet plant and to explore its effects on intestinal glucose absorption and insulin secretion. The authors hypothesized that the plasma glucose level could be reduced through the inhibition of glucose absorption and/or the enhancement of insulin secretion. Administration of the extract (0.5 and 1 g/kg body weight) in an oral glucose tolerance test led to a significant reduction in plasma glucose levels in 30 minutes after the administration in moderately diabetic rats, as compared with untreated rats (P < .05), and this was at a faster rate than the use of an antidiabetic drug, glibenclamide. The inhibition of glucose absorption through the small intestine was investigated using an everted intestinal sac. The results showed that the extract at concentrations of 0.156 to 5 mg/mL caused a reduction of glucose absorption in a dose response manner. The maximum response was noted at a dose of 2.5 mg/mL. The promotion of the extract on insulin secretion was confirmed by incubating beta cell of pancreatic islets and INS-1E insulinoma cells with the extract at 1 to 1000 microg/mL. These observations suggest that the aqueous extract from the A indicum plant has antidiabetic properties, which inhibited glucose absorption and stimulated insulin secretion. Phytochemical screening also revealed that the extract contained alkaloids, flavonoids, tannins, glycosides, and saponins that could account for the observed pharmacologic effects of the plant extract. PMID:19761892

  15. Superoxide anions produced by Streptococcus pyogenes group A-stimulated keratinocytes are responsible for cellular necrosis and bacterial growth inhibition.

    PubMed

    Regnier, Elodie; Grange, Philippe A; Ollagnier, Guillaume; Crickx, Etienne; Elie, Laetitia; Chouzenoux, Sandrine; Weill, Bernard; Plainvert, Céline; Poyart, Claire; Batteux, Frédéric; Dupin, Nicolas

    2016-02-01

    Gram-positive Streptococcus pyogenes (group A Streptococcus or GAS) is a major skin pathogen and interacts with keratinocytes in cutaneous tissues. GAS can cause diverse suppurative and inflammatory infections, such as cellulitis, a common acute bacterial dermo-hypodermitis with a high morbidity. Bacterial isolation yields from the lesions are low despite the strong local inflammation observed, raising numerous questions about the pathogenesis of the infection. Using an in vitro model of GAS-infected keratinocytes, we show that the major ROS produced is the superoxide anion ([Formula: see text]), and that its production is time- and dose-dependent. Using specific modulators of ROS production, we show that [Formula: see text] is mainly synthesized by the cytoplasmic NADPH oxidase. Superoxide anion production leads to keratinocyte necrosis but incomplete inhibition of GAS growth, suggesting that GAS may be partially resistant to the oxidative burst. In conclusion, GAS-stimulated keratinocytes are able to develop an innate immune response based on the production of ROS. This local immune response limits GAS development and induces keratinocyte cell death, resulting in the skin lesions observed in patients with cellulitis. PMID:26621818

  16. A single injection of polyethylene-glycol granulocyte colony-stimulating factor strongly prolongs survival of mice with systemic candidiasis.

    PubMed

    van Spriel, A B; van den Herik-Oudijk, I E; van de Winkel, J G

    2000-06-01

    Systemic candidiasis is a life-threatening disease occurring in immunocompromized patients. Granulocyte colony-stimulating factor (G-CSF) reduces mortality in experimental invasive candidiasis. Covalent conjugation of polyethylene-glycol (peg) to proteins increases their stability and in vivo bioactivity. In this study, the effect of a single subcutaneous injection of peg-G-CSF on lethal candidiasis was assessed. This was performed in acute and chronic candidiasis models in non-neutropenic FVB/N mice. Peg-G-CSF rapidly increased circulating polymorphonuclear leukocyte (PMNL) numbers in mice, sustaining high for >4 days. Candida albicans outgrowth from kidneys of infected mice was strongly reduced after peg-G-CSF treatment (5.76 log cfu/g kidney vs 7.66 control), with absence of hyphal outgrowth and enhanced PMNL influx. Moreover, peg-G-CSF increased survival of C. albicans -infected mice, whereas efficacy of uncoupled G-CSF was obtained only after repeated treatment. These data document a potent in vivo biological effect of peg-G-CSF, resulting in strongly enhanced resistance against systemic candidiasis. PMID:10843742

  17. Signatures of the Self-Similar Regime of Strongly Coupled Stimulated Brillouin Scattering for Efficient Short Laser Pulse Amplification

    NASA Astrophysics Data System (ADS)

    Lancia, L.; Giribono, A.; Vassura, L.; Chiaramello, M.; Riconda, C.; Weber, S.; Castan, A.; Chatelain, A.; Frank, A.; Gangolf, T.; Quinn, M. N.; Fuchs, J.; Marquès, J.-R.

    2016-02-01

    Plasma-based laser amplification is considered as a possible way to overcome the technological limits of present day laser systems and achieve exawatt laser pulses. Efficient amplification of a picosecond laser pulse by stimulated Brillouin scattering (SBS) of a pump pulse in a plasma requires to reach the self-similar regime of the strongly coupled (SC) SBS. In this Letter, we report on the first observation of the signatures of the transition from linear to self-similar regimes of SC-SBS, so far only predicted by theory and simulations. With a new fully head-on collision geometry, subpicosecond pulses are amplified by a factor of 5 with energy transfers of few tens of mJ. We observe pulse shortening, frequency spectrum broadening, and down-shifting for increasing gain, signatures of SC-SBS amplification entering the self-similar regime. This is also confirmed by the power law dependence of the gain on the amplification length: doubling the interaction length increases the gain by a factor 1.4. Pump backward Raman scattering (BRS) on SC-SBS amplification has been measured for the first time, showing a strong decrease of the BRS amplitude and frequency bandwidth when SBS seed amplification occurs.

  18. Signatures of the Self-Similar Regime of Strongly Coupled Stimulated Brillouin Scattering for Efficient Short Laser Pulse Amplification.

    PubMed

    Lancia, L; Giribono, A; Vassura, L; Chiaramello, M; Riconda, C; Weber, S; Castan, A; Chatelain, A; Frank, A; Gangolf, T; Quinn, M N; Fuchs, J; Marquès, J-R

    2016-02-19

    Plasma-based laser amplification is considered as a possible way to overcome the technological limits of present day laser systems and achieve exawatt laser pulses. Efficient amplification of a picosecond laser pulse by stimulated Brillouin scattering (SBS) of a pump pulse in a plasma requires to reach the self-similar regime of the strongly coupled (SC) SBS. In this Letter, we report on the first observation of the signatures of the transition from linear to self-similar regimes of SC-SBS, so far only predicted by theory and simulations. With a new fully head-on collision geometry, subpicosecond pulses are amplified by a factor of 5 with energy transfers of few tens of mJ. We observe pulse shortening, frequency spectrum broadening, and down-shifting for increasing gain, signatures of SC-SBS amplification entering the self-similar regime. This is also confirmed by the power law dependence of the gain on the amplification length: doubling the interaction length increases the gain by a factor 1.4. Pump backward Raman scattering (BRS) on SC-SBS amplification has been measured for the first time, showing a strong decrease of the BRS amplitude and frequency bandwidth when SBS seed amplification occurs. PMID:26943539

  19. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    ERIC Educational Resources Information Center

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  20. Cortical Inhibition in Attention Deficit Hyperactivity Disorder: New Insights from the Electroencephalographic Response to Transcranial Magnetic Stimulation

    ERIC Educational Resources Information Center

    Bruckmann, Sarah; Hauk, Daniela; Roessner, Veit; Resch, Franz; Freitag, Christine M.; Kammer, Thomas; Ziemann, Ulf; Rothenberger, Aribert; Weisbrod, Matthias; Bender, Stephan

    2012-01-01

    Attention deficit hyperactivity disorder is one of the most frequent neuropsychiatric disorders in childhood. Transcranial magnetic stimulation studies based on muscle responses (motor-evoked potentials) suggested that reduced motor inhibition contributes to hyperactivity, a core symptom of the disease. Here we employed the N100 component of the…

  1. Phosphate Treatment Strongly Inhibits New Arbuscule Development But Not the Maintenance of Arbuscule in Mycorrhizal Rice Roots.

    PubMed

    Kobae, Yoshihiro; Ohmori, Yoshihiro; Saito, Chieko; Yano, Koji; Ohtomo, Ryo; Fujiwara, Toru

    2016-05-01

    Phosphorus (P) is a crucial nutrient for plant growth, but its availability to roots is limited in soil. Arbuscular mycorrhizal (AM) symbiosis is a promising strategy for improving plant P acquisition. However, P fertilizer reduces fungal colonization (P inhibition) and compromises mycorrhizal P uptake, warranting studies on the mechanistic basis of P inhibition. In this study, early morphological changes in P inhibition were identified in rice (Oryza sativa) using fungal cell wall staining and live-cell imaging of plant membranes that were associated with arbuscule life cycles. Arbuscule density decreased, and aberrant hyphal branching was observed in roots at 5 h after P treatment. Although new arbuscule development was severely inhibited, preformed arbuscules remained intact and longevity remained constant. P inhibition was accelerated in the rice pt11-1 mutant, which lacks P uptake from arbuscule branches, suggesting that mature arbuscules are stabilized by the symbiotic P transporter under high P condition. Moreover, P treatment led to increases in the number of vesicles, in which lipid droplets accumulated and then decreased within a few days. The development of new arbuscules resumed within by 2 d. Our data established that P strongly and temporarily inhibits new arbuscule development, but not intraradical accommodation of AM fungi. PMID:26979330

  2. Reductions in the Cardiac Transient Outward K+ Current Ito Caused by Chronic β-Adrenergic Receptor Stimulation Are Partly Rescued by Inhibition of Nuclear Factor κB.

    PubMed

    Panama, Brian K; Korogyi, Adam S; Aschar-Sobbi, Roozbeh; Oh, Yena; Gray, Charles B B; Gang, Hongying; Brown, Joan Heller; Kirshenbaum, Lorrie A; Backx, Peter H

    2016-02-19

    The fast transient outward potassium current (Ito,f) plays a critical role in the electrical and contractile properties of the myocardium. Ito,f channels are formed by the co-assembly of the pore-forming α-subunits, Kv4.2 and Kv4.3, together with the accessory β-subunit KChIP2. Reductions of Ito,f are common in the diseased heart, which is also associated with enhanced stimulation of β-adrenergic receptors (β-ARs). We used cultured neonatal rat ventricular myocytes to examine how chronic β-AR stimulation decreases Ito,f. To determine which downstream pathways mediate these Ito,f changes, adenoviral infections were used to inhibit CaMKIIδc, CaMKIIδb, calcineurin, or nuclear factor κB (NF-κB). We observed that chronic β-AR stimulation with isoproterenol (ISO) for 48 h reduced Ito,f along with mRNA expression of all three of its subunits (Kv4.2, Kv4.3, and KChIP2). Inhibiting either CaMKIIδc nor CaMKIIδb did not prevent the ISO-mediated Ito,f reductions, even though CaMKIIδc and CaMKIIδb clearly regulated Ito,f and the mRNA expression of its subunits. Likewise, calcineurin inhibition did not prevent the Ito,f reductions induced by β-AR stimulation despite strongly modulating Ito,f and subunit mRNA expression. In contrast, NF-κB inhibition partly rescued the ISO-mediated Ito,f reductions in association with restoration of KChIP2 mRNA expression. Consistent with these observations, KChIP2 promoter activity was reduced by p65 as well as β-AR stimulation. In conclusion, NF-κB, and not CaMKIIδ or calcineurin, partly mediates the Ito,f reductions induced by chronic β-AR stimulation. Both mRNA and KChIP2 promoter data suggest that the ISO-induced Ito,f reductions are, in part, mediated through reduced KChIP2 transcription caused by NF-κB activation. PMID:26742842

  3. AR-12 Inhibits Multiple Chaperones Concomitant With Stimulating Autophagosome Formation Collectively Preventing Virus Replication.

    PubMed

    Booth, Laurence; Roberts, Jane L; Ecroyd, Heath; Tritsch, Sarah R; Bavari, Sina; Reid, St Patrick; Proniuk, Stefan; Zukiwski, Alexander; Jacob, Abraham; Sepúlveda, Claudia S; Giovannoni, Federico; García, Cybele C; Damonte, Elsa; González-Gallego, Javier; Tuñón, María J; Dent, Paul

    2016-10-01

    We have recently demonstrated that AR-12 (OSU-03012) reduces the function and ATPase activities of multiple HSP90 and HSP70 family chaperones. Combined knock down of chaperones or AR-12 treatment acted to reduce the expression of virus receptors and essential glucosidase proteins. Combined knock down of chaperones or AR-12 treatment inactivated mTOR and elevated ATG13 S318 phosphorylation concomitant with inducing an endoplasmic reticulum stress response that in an eIF2α-dependent fashion increased Beclin1 and LC3 expression and autophagosome formation. Over-expression of chaperones prevented the reduction in receptor/glucosidase expression, mTOR inactivation, the ER stress response, and autophagosome formation. AR-12 reduced the reproduction of viruses including Mumps, Influenza, Measles, Junín, Rubella, HIV (wild type and protease resistant), and Ebola, an effect replicated by knock down of multiple chaperone proteins. AR-12-stimulated the co-localization of Influenza, EBV and HIV virus proteins with LC3 in autophagosomes and reduced viral protein association with the chaperones HSP90, HSP70, and GRP78. Knock down of Beclin1 suppressed drug-induced autophagosome formation and reduced the anti-viral protection afforded by AR-12. In an animal model of hemorrhagic fever virus, a transient exposure of animals to low doses of AR-12 doubled animal survival from ∼30% to ∼60% and suppressed liver damage as measured by ATL, GGT and LDH release. Thus through inhibition of chaperone protein functions; reducing the production, stability and processing of viral proteins; and stimulating autophagosome formation/viral protein degradation, AR-12 acts as a broad-specificity anti-viral drug in vitro and in vivo. We argue future patient studies with AR-12 are warranted. J. Cell. Physiol. 231: 2286-2302, 2016. © 2016 Wiley Periodicals, Inc. PMID:27187154

  4. Afferent vagal nerve stimulation resets baroreflex neural arc and inhibits sympathetic nerve activity

    PubMed Central

    Saku, Keita; Kishi, Takuya; Sakamoto, Kazuo; Hosokawa, Kazuya; Sakamoto, Takafumi; Murayama, Yoshinori; Kakino, Takamori; Ikeda, Masataka; Ide, Tomomi; Sunagawa, Kenji

    2014-01-01

    Abstract It has been established that vagal nerve stimulation (VNS) benefits patients and/or animals with heart failure. However, the impact of VNS on sympathetic nerve activity (SNA) remains unknown. In this study, we investigated how vagal afferent stimulation (AVNS) impacts baroreflex control of SNA. In 12 anesthetized Sprague–Dawley rats, we controlled the pressure in isolated bilateral carotid sinuses (CSP), and measured splanchnic SNA and arterial pressure (AP). Under a constant CSP, increasing the voltage of AVNS dose dependently decreased SNA and AP. The averaged maximal inhibition of SNA was ‐28.0 ± 10.3%. To evaluate the dynamic impacts of AVNS on SNA, we performed random AVNS using binary white noise sequences, and identified the transfer function from AVNS to SNA and that from SNA to AP. We also identified transfer functions of the native baroreflex from CSP to SNA (neural arc) and from SNA to AP (peripheral arc). The transfer function from AVNS to SNA strikingly resembled the baroreflex neural arc and the transfer functions of SNA to AP were indistinguishable whether we perturbed ANVS or CSP, indicating that they likely share common central and peripheral neural mechanisms. To examine the impact of AVNS on baroreflex, we changed CSP stepwise and measured SNA and AP responses with or without AVNS. AVNS resets the sigmoidal neural arc downward, but did not affect the linear peripheral arc. In conclusion, AVNS resets the baroreflex neural arc and induces sympathoinhibition in the same manner as the control of SNA and AP by the native baroreflex. PMID:25194023

  5. Bioactivity of Benthic and Picoplanktonic Estuarine Cyanobacteria on Growth of Photoautotrophs: Inhibition versus Stimulation

    PubMed Central

    Lopes, Viviana R.; Vasconcelos, Vitor M.

    2011-01-01

    Understanding potential biochemical interactions and effects among cyanobacteria and other organisms is one of the main keys to a better knowledge of microbial population structuring and dynamics. In this study, the effects of cyanobacteria from benthos and plankton of estuaries on other cyanobacteria and green algae growth were evaluated. To understand how the estuarine cyanobacteria might influence the dynamics of phytoplankton, experiments were carried out with the freshwater species Microcystis aeruginosa and Chlorella sp., and the marine Synechocystis salina and Nannochloropsis sp. exposed to aqueous and organic (70% methanol) crude extracts of cyanobacteria for 96 h. The most pronounced effect observed was the growth stimulation. Growth inhibition was also observed for S. salina and M. aeruginosa target-species at the highest and lowest concentrations of cyanobacterial extracts. The methanolic crude extract of Phormidium cf. chalybeum LEGE06078 was effective against S. salina growth in a concentration-dependent manner after 96 h-exposure. All of the cyanobacterial isolates showed some bioactivity on the target-species growth, i.e., inhibitory or stimulating effects. These results indicate that the analyzed cyanobacterial isolates can potentially contribute to blooms’ proliferation of other cyanobacteria and to the abnormal growth of green algae disturbing the dynamic of estuarine phytoplankton communities. Since estuaries are transitional ecosystems, the benthic and picoplanktonic estuarine cyanobacteria can change both freshwater and marine phytoplankton succession, competition and bloom formation. Furthermore, a potential biotechnological application of these isolates as a tool to control cyanobacteria and microalgae proliferation can be feasible. This work is the first on the subject of growth responses of photoautotrophs to cyanobacteria from Atlantic estuarine environments. PMID:21673889

  6. Ba2+ inhibition of VIP- and A23187-stimulated Cl- secretion by T84 cell monolayers

    SciTech Connect

    Mandel, K.G.; McRoberts, J.A.; Beuerlein, G.; Foster, E.S.; Dharmsathaphorn, K.

    1986-03-01

    Addition of either 10(-8) M vasoactive intestinal polypeptide (VIP) or 10(-6) M A23187 to T84 cell monolayers, grown on permeable supports and mounted in Ussing chambers, stimulated net Cl- secretion. The effect of 10(-6) M A23187 on Cl- flux was consistently smaller than that observed with 10(-8) M VIP. In both cases the increase in net Cl- secretion accounted for the entire change in the observed short-circuit current (Isc). Since Cl- enters the cells through a basolaterally localized Na+-K+-Cl(-)-cotransport system (J. Clin. Invest. 75: 462, 1985), the fate of K+, which is cotransported with Cl- during VIP, and A23187-mediated Cl- secretion was explored. Unidirectional and net transepithelial 42K+ flux rates were negligible compared with 36Cl- flux rates (less than 4% of Cl- flux), indicating that little K+ was secreted along with Cl-. K+ recycling across the basolateral membrane was suggested from experiments in which 86Rb+ efflux (as a tracer for K+) was measured across the apical and basolateral membranes of 86Rb+ -preloaded monolayers under voltage-clamped conditions. In the absence of secretagogues, 86Rb+ efflux was 10-fold higher across the basolateral membrane than across the apical membrane. 86Rb+ efflux across the basolateral membrane was accelerated two- to threefold by addition of either VIP or A23187. In each case accelerated efflux was inhibited by 5 mM Ba2+. Cl- secretion induced by VIP or A23187 was also inhibited by serosal addition of Ba2+.

  7. [Wogonin inhibits IGF-1-stimulated cell growth and estrogen receptor α expression in breast adenocarcinoma cell and angiogenesis of chick chorioallantoic membrane].

    PubMed

    Ma, Xing; Xie, Kun-Peng; Shang, Fei; Huo, Hong-Nan; Wang, Li-Meng; Xie, Ming-Jie

    2012-04-25

    The aim of the present study was to investigate the involvements of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. MCF-7 cells (human breast adenocarcinoma cell line) were subjected to several drugs, including IGF-1, wogonin and ER inhibitor ICI182780, alone or in combination. MTT assay was used to detect breast cancer proliferation. Western blot was used to analyze ERα and p-Akt expression levels. CAM models prepared from 6-day chicken eggs were employed to evaluate angiogenesis inhibition. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis. These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model. PMID:22513472

  8. Dithiocarbamates strongly inhibit carbonic anhydrases and show antiglaucoma action in vivo.

    PubMed

    Carta, Fabrizio; Aggarwal, Mayank; Maresca, Alfonso; Scozzafava, Andrea; McKenna, Robert; Masini, Emanuela; Supuran, Claudiu T

    2012-02-23

    A series of dithiocarbamates were prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. The X-ray crystal structure of the hCA II adduct with morpholine dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the dithiocarbamate zinc-binding function. Some dithiocarbamates showed an effective intraocular pressure lowering activity in an animal model of glucoma. PMID:22276570

  9. Dithiocarbamates strongly inhibit carbonic anhydrases and show antiglaucoma action in vivo#

    PubMed Central

    Carta, Fabrizio; Aggarwal, Mayank; Maresca, Alfonso; Scozzafava, Andrea; McKenna, Robert; Masini, Emanuela; Supuran, Claudiu T.

    2012-01-01

    A series of dithiocarbamates was prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of 4 human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. X-ray crystal structure of hCA II adduct with morpholine dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the dithiocarbamate zinc-binding function. Some dithiocarbamates showed effective intraocular pressure lowering activity in an animal model of glucoma. PMID:22276570

  10. Safflower Yellow regulates microglial polarization and inhibits inflammatory response in LPS-stimulated Bv2 cells.

    PubMed

    Yang, Xing-Wang; Li, Yan-Hua; Zhang, Hui; Zhao, Yong-Fei; Ding, Zhi-Bin; Yu, Jie-Zhong; Liu, Chun-Yun; Liu, Jian-Chun; Jiang, Wei-Jia; Feng, Qian-Jin; Xiao, Bao-Guo; Ma, Cun-Gen

    2016-03-01

    Activated microglia, especially polarized M1 cells, produce pro-inflammatory cytokines and free radicals, thereby contributing directly to neuroinflammation and various brain disorders. Given that excessive or chronic neuroinflammation within the central nervous system (CNS) exacerbates neuronal damage, molecules that modulate neuroinflammation are candidates as neuroprotective agents. In this study, we provide evidence that Safflor yellow (SY), the main active component in the traditional Chinese medicine safflower, modulates inflammatory responses by acting directly on BV2 microglia. LPS stimulated BV2 cells to upregulate expression of TLR4-Myd88 and MAPK-NF-κB signaling pathways and to release IL-1β, IL-6, TNF-α, and COX-2. However, SY treatment inhibited expression of TLR4-Myd88 and p-38/p-JNK-NF-κB, downregulated expression of iNOS, CD16/32, and IL-12, and upregulated CD206 and IL-10. In conclusion, our results demonstrate that SY exerts an anti-inflammatory effect on BV2 microglia, possibly through TLR-4/p-38/p-JNK/NF-κB signaling pathways and the conversion of microglia from inflammatory M1 to an anti-inflammatory M2 phenotype. PMID:26634402

  11. The Oncogene LRF Stimulates Proliferation of Mesenchymal Stem Cells and Inhibits Their Chondrogenic Differentiation

    PubMed Central

    Li, Huan; Acharya, Chitrangada; Kumari, Ratna; Fierro, Fernando; Haudenschild, Dominik R.; Nolta, Jan; Di Cesare, Paul E.

    2013-01-01

    Objective. The oncogene leukemia/lymphoma-related factor (LRF) enhances chondrosarcoma proliferation and malignancy. This study aimed to investigate the roles of LRF in chondrogenic differentiation of primary human bone marrow–derived mesenchymal stem cells (BMSCs). Design. LRF was overexpressed in BMSC by lentiviral transduction. Chondrogenic differentiation of BMSC was induced by high-density pellet culture. Western blotting and real-time polymerase chain reaction were used to investigate changes in protein and mRNA levels, respectively, during chondrogenesis. Safranin-O staining, immunohistochemistry, and glycoaminoglycan contents were used to assess cartilage matrix deposition. BMSC proliferation was determined by mitochondrial dehydrogenase activity and cell counting. Cell cycle profiling was performed by flow cytometry. Results. LRF overexpression effectively inhibited protein and mRNA expression of chondrocyte markers and cartilage matrix deposition during chondrogenesis of BMSC. Endogenous LRF expression was constitutively high in undifferentiated BMSC but remained low in primary articular chondrocytes. Endogenous LRF protein was downregulated in a time-dependent manner during chondrogenesis. BMSCs overexpressing LRF had higher proliferation rates and cell population in the S phase. LRF suppressed p53 expression during chondrogenesis and this might prevent differentiating chondrocytes from entering a quiescent state. Conclusion. Our data showed that LRF is important for stimulating stem cell proliferation and cell cycle progression. It is known that LRF is highly expressed in the mouse limb buds prior to overt chondrogenesis; thus, LRF might function to prevent premature chondrogenic differentiation of stem cells. PMID:26069677

  12. Pantethine inhibits cholesterol and fatty acid syntheses and stimulates carbon dioxide formation in isolated rat hepatocytes.

    PubMed

    Cighetti, G; Del Puppo, M; Paroni, R; Fiorica, E; Galli Kienle, M

    1987-02-01

    The effects of pantethine on cholesterol and fatty acid metabolism were investigated in isolated rat hepatocytes. Preincubation of the cells with pantethine induced a concentration-dependent decrease of the radioactivity incorporated into carbon dioxide and lipids in incubations with [2-14C]acetate. When pantethine and the labeled substrate were simultaneously added to the cell suspension, there was an enhancement of carbon dioxide radioactivity at short incubation time (5 min) whereas, at longer incubation time, values were comparable to those of controls; lipid radioactivity, instead, was dramatically reduced by pantethine even at short incubation time and decreased further during the incubation, being 23% of that of controls at 60 min. Analysis of the incubation medium showed that pantethine induced a concentration- and time-dependent release of acetate into the medium. Results of the effect of the acetate concentration on the incorporation of [2-14C]acetate radioactivity into CO2 and lipids in control hepatocytes allowed the conclusion that the above-described modifications induced by pantethine are only partially attributable to the dilution of the labeled substrate, and that catabolism of acetate to carbon dioxide is stimulated by the disulphide pantethine, whereas cholesterol and fatty acid syntheses are inhibited. PMID:3106549

  13. Influenza virus-infected dendritic cells stimulate strong proliferative and cytolytic responses from human CD8+ T cells.

    PubMed Central

    Bhardwaj, N; Bender, A; Gonzalez, N; Bui, L K; Garrett, M C; Steinman, R M

    1994-01-01

    Antigen-specific, CD8+, cytolytic T lymphocytes (CTLs) could potentially provide resistance to several infectious and malignant diseases. However, the cellular requirements for the generation of specific CTLs in human lymphocyte cultures are not well defined, and repetitive stimulation with antigen is often required. We find that strong CD8+ CTL responses to influenza virus can be generated from freshly isolated blood T cells, as long as dendritic cells are used as antigen presenting cells (APCs). Small numbers of dendritic cells (APC:T cell ratio of 1:50-1:100) induce these CTL responses from most donors in 7 d of culture, but monocytes are weak or inactive. Whereas both dendritic cells and monocytes are infected with influenza virus, the former serve as effective APCs for the induction of CD8+ T cells while the latter act as targets for the CTLs that are induced. The strong CD8+ response to influenza virus-infected dendritic cells is accompanied by extensive proliferation of the CD8+ T cells, but the response can develop in the apparent absence of CD4+ helpers or exogenous lymphokines. CD4+ influenza virus-specific CTLs can also be induced by dendritic cells, but the cultures initially must be depleted of CD8+ cells. These findings should make it possible to use dendritic cells to generate human, antigen-specific, CD8+ CTLs to other targets. The results illustrate the principle that efficient T cell-mediated responses develop in two stages: an afferent limb in which dendritic cells are specialized APCs and an efferent limb in which the primed T cells carry out an immune response to many types of presenting cells. Images PMID:8040335

  14. Muscarinic cholinergic inhibition of beta-adrenergic stimulation of phospholamban phosphorylation and CaS transport in guinea pig ventricles

    SciTech Connect

    Lindemann, J.P.; Watanabe, A.M.

    1985-10-25

    The effects of muscarinic cholinergic stimulation on beta-adrenergic induced increases in phospholamban phosphorylation and CaS transport were studied in intact myocardium. Isolated guinea pig ventricles were perfused via the coronary arteries with TSPi, after which membrane vesicles were isolated from individual hearts. Isoproterenol produced reversible increases in TSP incorporation into phospholamban. Associated with the increases in TSP incorporation were increases in the initial rate of phosphate-facilitated CaS uptake measured in aliquots of the same membrane vesicles isolated from the perfused hearts. The increases in TSP incorporation and calcium transport were significantly attenuated by the simultaneous administration of acetylcholine. Acetylcholine also attenuated increases in phospholamban phosphorylation and CaS uptake produced by the phosphodiesterase inhibitor isobutylmethylxanthine and forskolin. The contractile effects of all agents which increased cAMP levels (increased contractility and a reduction in the t1/2 of relaxation) were also attenuated by acetylcholine. The inhibitory effects of acetylcholine were associated with attenuation of the increases in cAMP levels produced by isoproterenol and isobutylmethylxanthine but not by forskolin. Acetylcholine also increased the rate of reversal of the functional and biochemical effects of isoproterenol by propranolol without affecting cAMP levels. These results suggest that cholinergic agonists inhibit the functional effects of beta-adrenergic stimulation in part by inhibition of phospholamban phosphorylation. This inhibition may be mediated by two potential mechanisms: inhibition of beta-adrenergic activation of adenylate cyclase and stimulation of dephosphorylation.

  15. Pregnancy-associated plasma protein-a production in rat granulosa cells: stimulation by follicle-stimulating hormone and inhibition by the oocyte-derived bone morphogenetic protein-15.

    PubMed

    Matsui, Motozumi; Sonntag, Barbara; Hwang, Seong Soo; Byerly, Tara; Hourvitz, Ariel; Adashi, Eli Y; Shimasaki, Shunichi; Erickson, Gregory F

    2004-08-01

    Pregnancy-associated plasma protein-A (PAPP-A) is the major IGF binding protein-4 (IGFBP-4) protease in follicular fluid, consistent with its proposed role in folliculogenesis. Despite growing interest, almost nothing is known about how PAPP-A expression is regulated in any tissue. Here we show that FSH and oocytes regulate PAPP-A expression in granulosa cells (GCs). By in situ hybridization, ovary PAPP-A mRNA was markedly increased by pregnant mare serum gonadotropin treatment, and the message was localized to the membrana GCs but not cumulus GCs (CGCs) of dominant follicles. To explore the mechanism, we used primary cultures of rat GCs. Control (untreated) cells produced little or no PAPP-A spontaneously. Conversely, FSH markedly stimulated PAPP-A mRNA and protein in a dose- and time-dependent fashion. Interestingly, PAPP-A expression in isolated CGCs was also strongly induced by FSH, and the induction was inhibited by added oocytes. To investigate the nature of the inhibition, we tested the effect of oocyte-derived bone morphogenetic protein-15 (BMP-15). BMP-15 alone had no effect on basal levels of PAPP-A expression by cultures of membrana GCs or CGCs. However, BMP-15 markedly inhibited the FSH stimulation of PAPP-A production in a dose-dependent manner. The cleavage of IGFBP-4 by conditioned media from FSH-treated GCs was completely inhibited by anti-PAPP-A antibody, indicating the IGFBP-4 protease secreted by GCs is PAPP-A. These results demonstrate stimulatory and inhibitory roles for FSH and BMP-15, respectively, in regulating PAPP-A production by GCs. We propose that FSH and oocyte-derived BMP-15 form a controlling network that ensures the spatiotemporal pattern of GC PAPP-A expression in the dominant follicle. PMID:15087430

  16. Xanthates and trithiocarbonates strongly inhibit carbonic anhydrases and show antiglaucoma effects in vivo.

    PubMed

    Carta, Fabrizio; Akdemir, Atilla; Scozzafava, Andrea; Masini, Emanuela; Supuran, Claudiu T

    2013-06-13

    Dithiocarbamates (DTCs) were recently discovered as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. A series of xanthates and a trithiocarbonate, structurally related to the DTCs, were prepared by reaction of alcohols/thiols with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms, hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar xanthate/trithiocarbonate inhibitors targeting these CAs were detected. A docking study of some xanthates within the CA II active site showed that these compounds bind in a similar manner with the dithiocarbamates, coordinating monodentately to the Zn(II) ion from the enzyme active site. Several xanthates showed potent intraocular pressure lowering activity in two animal models of glaucoma via the topical administration. Xanthates and thioxanthates represent two novel, promising classes of CA inhibitors. PMID:23647428

  17. Dithiocarbamates strongly inhibit the β-class carbonic anhydrases from Mycobacterium tuberculosis.

    PubMed

    Maresca, Alfonso; Carta, Fabrizio; Vullo, Daniela; Supuran, Claudiu T

    2013-04-01

    A series of N-mono- and N,N-disubstituted dithiocarbamates have been investigated as inhibitors of two β-carbonic anhydrases (CAs, EC 4.2.1.1) from the bacterial pathogen Mycobacterium tuberculosis, mtCA 1 (Rv1284) and mtCA 3 (Rv3273). Both enzymes were inhibited with efficacies between the subnanomolar to the micromolar one, depending on the substitution pattern at the nitrogen atom from the dithiocarbamate zinc-binding group. Aryl, arylalkyl-, heterocyclic as well as aliphatic and amino acyl such moieties led to potent mtCA 1 and 3 inhibitors in both the N-mono- and N,N-disubstituted dithiocarbamate series. This new class of β-CA inhibitors may have the potential for developing antimycobacterial agents with a diverse mechanism of action compared to the clinically used drugs for which many strains exhibit multi-drug/extensive multi-drug resistance. PMID:22145736

  18. CGRP may regulate bone metabolism through stimulating osteoblast differentiation and inhibiting osteoclast formation.

    PubMed

    He, Haitao; Chai, Jianshen; Zhang, Shengfu; Ding, Linlin; Yan, Peng; Du, Wenjun; Yang, Zhenzhou

    2016-05-01

    Calcitonin-gene-related peptide (CGRP) is a neuropeptide, which is widely distributed throughout the central and peripheral nervous systems. Numerous mechanisms underlying the action of CGRP in osteoblast-associated cells have been suggested for bone growth and metabolism. The present study was designed to closely investigate the osteoblast‑ and osteoclast-associated mechanisms of the effect of CGRP administration on bone metabolism in primary osteoblasts. Primary osteoblasts were obtained from newborn rabbit calvaria and incubated with different concentrations of human CGRP (hCGRP), hCGRP and hCGRP (8‑37), or without treatment as a control. Intracellular calcium (Ca2+) and cyclic adenosine monophosphate (cAMP) were detected following treatment, as well as the expression levels of osteoblast differentiation markers, including activating transcription factor‑4 (ATF4) and osteocalcin (OC), and receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG). The isolated primary osteoblasts were found to stain positively for ALP. hCGRP treatment had no significant effect on transient intracellular Ca2+ in the osteoblasts. Treatment of the osteoblasts with hCGRP led to elevations in the expression levels of cAMP, ATF4 and OPG, and downregulation in the expression of RANKL, in a dose‑dependent manner. These effects were markedly reversed by the addition of hCGRP (8‑37). The results of the present study demonstrated that CGRP administration not only stimulated osteoblast differentiation, as demonstrated by upregulated expression levels of ATF4 and OC in the hCGRP‑treated osteoblasts, but also inhibited OPG/RANKL‑regulated osteoclastogenesis. CGRP may act as a modulator of bone metabolism through osteoblast and osteoclast-associated mechanisms, which result in osteoblast formation with subsequent activation of bone formation. PMID:27035229

  19. Co-stimulation of T cells via CD28 inhibits human IgE production; reversal by pertussis toxin.

    PubMed Central

    Van der Pouw-Kraan, C T; Rensink, H J; Rappuoli, R; Aarden, L A

    1995-01-01

    In lymphocyte cultures, IgE production was achieved by stimulating T cells with anti-CD2 and IL-2. Here we show that anti-CD28, in the presence or absence of IL-2, reduces this IgE production approximately 10-fold. This inhibition of IgE production was almost completely reversed by Pertussis toxin (PT). PT had no effect on IgE production when the cells were stimulated in the absence of anti-CD28. No major effects of PT were found on IgM production. PT had no effect on purified B cells, stimulated with IL-4 and anti-CD40. In the presence of saturating amounts of rIL-4 similar results were obtained, albeit the absolute amounts of IgE produced were higher in all situations. Furthermore, PT-induced IgE production was still dependent on IL-4, as was evident from experiments in which anti-IL-4 was added to the culture. The IgE enhancing effect was dependent on the adenosine diphosphate (ADP)-ribosyltransferase activity of PT, because a mutant molecule lacking this activity was not able to restore anti-CD28-induced inhibition of IgE synthesis. Thus, we show that co-stimulation with anti-CD28 causes an inhibition of T cell-dependent IgE production by B cells, which inhibition can be specifically overcome by PT. An analysis of the molecular pathways underlying this phenomenon may contribute to our understanding of the regulation of IgE synthesis in (patho)physiological conditions. PMID:7882571

  20. Wogonin inhibits multiple myeloma-stimulated angiogenesis via c-Myc/VHL/HIF-1α signaling axis

    PubMed Central

    Wang, Xiao-Ping; An, Teng; Tao, Lei; Zhou, Yu-Xin; Huang, Yu-Jie; Chen, Bao-An; Li, Zhi-Yu; You, Qi-Dong; Guo, Qing-Long; Wu, Zhao-Qiu

    2016-01-01

    Angiogenesis is associated with the progression of multiple myeloma (MM). Wogonin is an active mono-flavonoid with remarkable antitumor activity. However, its impact on MM-stimulated angiogenesis remains largely unknown. Here, we demonstrated that wogonin decreased expression and secretion of pro-angiogenic factors in MM cells via c-Myc/HIF-1α signaling axis, reducing MM-stimulated angiogenesis and MM cell proliferation in vivo. Overexpression of c-Myc in MM cells disrupted the balance between VHL SUMOylation and ubiquitination, and thus inhibited proteasome-mediated HIF-1α degradation. Impaired function of VHL ubiquitination complex in c-Myc-overexpressing cells was fully reversed by wogonin treatment via increasing HIF-1α-VHL interaction and promoting HIF-1α degradation. Collectively, our in vitro and in vivo studies reveal for the first time that wogonin represses MM-stimulated angiogenesis and tumor progression via c-Myc/VHL/HIF-1α signaling axis. PMID:26735336

  1. Gentle Mechanical Skin Stimulation Inhibits Micturition Contractions via the Spinal Opioidergic System and by Decreasing Both Ascending and Descending Transmissions of the Micturition Reflex in the Spinal Cord.

    PubMed

    Hotta, Harumi; Watanabe, Nobuhiro

    2015-01-01

    Recently, we found that gentle mechanical skin stimulation inhibits the micturition reflex in anesthetized rats. However, the central mechanisms underlying this inhibition have not been determined. This study aimed to clarify the central neural mechanisms underlying this inhibitory effect. In urethane-anesthetized rats, cutaneous stimuli were applied for 1 min to the skin of the perineum using an elastic polymer roller with a smooth, soft surface. Inhibition of rhythmic micturition contractions by perineal stimulation was abolished by naloxone, an antagonist of opioidergic receptors, administered into the intrathecal space of the lumbosacral spinal cord at doses of 2-20 μg but was not affected by the same doses of naloxone administered into the subarachnoid space of the cisterna magna. Next, we examined whether perineal rolling stimulation inhibited the descending and ascending limbs of the micturition reflex. Perineal rolling stimulation inhibited bladder contractions induced by electrical stimulation of the pontine micturition center (PMC) or the descending tract of the micturition reflex pathway. It also inhibited the bladder distension-induced increase in the blood flow of the dorsal cord at L5-S1, reflecting the neural activity of this area, as well as pelvic afferent-evoked field potentials in the dorsal commissure at the lumbosacral level; these areas contain long ascending neurons to the PMC. Neuronal activities in this center were also inhibited by the rolling stimulation. These results suggest that the perineal rolling stimulation activates the spinal opioidergic system and inhibits both ascending and descending transmissions of the micturition reflex pathway in the spinal cord. These inhibitions would lead to the shutting down of positive feedback between the bladder and the PMC, resulting in inhibition of the micturition reflex. Based on the central neural mechanisms we show here, gentle perineal stimulation may be applicable to several different types

  2. Gentle Mechanical Skin Stimulation Inhibits Micturition Contractions via the Spinal Opioidergic System and by Decreasing Both Ascending and Descending Transmissions of the Micturition Reflex in the Spinal Cord

    PubMed Central

    Hotta, Harumi; Watanabe, Nobuhiro

    2015-01-01

    Recently, we found that gentle mechanical skin stimulation inhibits the micturition reflex in anesthetized rats. However, the central mechanisms underlying this inhibition have not been determined. This study aimed to clarify the central neural mechanisms underlying this inhibitory effect. In urethane-anesthetized rats, cutaneous stimuli were applied for 1 min to the skin of the perineum using an elastic polymer roller with a smooth, soft surface. Inhibition of rhythmic micturition contractions by perineal stimulation was abolished by naloxone, an antagonist of opioidergic receptors, administered into the intrathecal space of the lumbosacral spinal cord at doses of 2–20 μg but was not affected by the same doses of naloxone administered into the subarachnoid space of the cisterna magna. Next, we examined whether perineal rolling stimulation inhibited the descending and ascending limbs of the micturition reflex. Perineal rolling stimulation inhibited bladder contractions induced by electrical stimulation of the pontine micturition center (PMC) or the descending tract of the micturition reflex pathway. It also inhibited the bladder distension-induced increase in the blood flow of the dorsal cord at L5–S1, reflecting the neural activity of this area, as well as pelvic afferent-evoked field potentials in the dorsal commissure at the lumbosacral level; these areas contain long ascending neurons to the PMC. Neuronal activities in this center were also inhibited by the rolling stimulation. These results suggest that the perineal rolling stimulation activates the spinal opioidergic system and inhibits both ascending and descending transmissions of the micturition reflex pathway in the spinal cord. These inhibitions would lead to the shutting down of positive feedback between the bladder and the PMC, resulting in inhibition of the micturition reflex. Based on the central neural mechanisms we show here, gentle perineal stimulation may be applicable to several different

  3. The Novel Antitubulin Agent TR-764 Strongly Reduces Tumor Vasculature and Inhibits HIF-1α Activation

    PubMed Central

    Porcù, Elena; Persano, Luca; Ronca, Roberto; Mitola, Stefania; Bortolozzi, Roberta; Romagnoli, Romeo; Oliva, Paola; Basso, Giuseppe; Viola, Giampietro

    2016-01-01

    Tubulin binding agents (TBAs) are commonly used in cancer therapy as antimitotics. It has been described that TBAs, like combretastatin A-4 (CA-4), present also antivascular activity and among its derivatives we identified TR-764 as a new inhibitor of tubulin polymerization, based on the 2-(alkoxycarbonyl)-3-(3′,4′,5′-trimethoxyanilino)benzo[b]thiophene molecular skeleton. The antiangiogenic activity of TR-764 (1–10 nM) was tested in vitro on human umbilical endothelial cells (HUVECs), and in vivo, on the chick embryo chorioallantoic membrane (CAM) and two murine tumor models. TR-764 binding to tubulin triggers cytoskeleton rearrangement without affecting cell cycle and viability. It leads to capillary tube disruption, increased cell permeability, and cell motility reduction. Moreover it disrupts adherens junctions and focal adhesions, through mechanisms involving VE-cadherin/β-catenin and FAK/Src. Importantly, TR-764 is active in hypoxic conditions significantly reducing HIF-1α. In vivo TR-764 (1–100 pmol/egg) remarkably blocks the bFGF proangiogenic activity on CAM and shows a stronger reduction of tumor mass and microvascular density both in murine syngeneic and xenograft tumor models, compared to the lead compound CA-4P. Altogether, our results indicate that TR-764 is a novel TBA with strong potential as both antivascular and antitumor molecule that could improve the common anticancer therapies, by overcoming hypoxia-induced resistance mechanisms. PMID:27292568

  4. The Novel Antitubulin Agent TR-764 Strongly Reduces Tumor Vasculature and Inhibits HIF-1α Activation.

    PubMed

    Porcù, Elena; Persano, Luca; Ronca, Roberto; Mitola, Stefania; Bortolozzi, Roberta; Romagnoli, Romeo; Oliva, Paola; Basso, Giuseppe; Viola, Giampietro

    2016-01-01

    Tubulin binding agents (TBAs) are commonly used in cancer therapy as antimitotics. It has been described that TBAs, like combretastatin A-4 (CA-4), present also antivascular activity and among its derivatives we identified TR-764 as a new inhibitor of tubulin polymerization, based on the 2-(alkoxycarbonyl)-3-(3',4',5'-trimethoxyanilino)benzo[b]thiophene molecular skeleton. The antiangiogenic activity of TR-764 (1-10 nM) was tested in vitro on human umbilical endothelial cells (HUVECs), and in vivo, on the chick embryo chorioallantoic membrane (CAM) and two murine tumor models. TR-764 binding to tubulin triggers cytoskeleton rearrangement without affecting cell cycle and viability. It leads to capillary tube disruption, increased cell permeability, and cell motility reduction. Moreover it disrupts adherens junctions and focal adhesions, through mechanisms involving VE-cadherin/β-catenin and FAK/Src. Importantly, TR-764 is active in hypoxic conditions significantly reducing HIF-1α. In vivo TR-764 (1-100 pmol/egg) remarkably blocks the bFGF proangiogenic activity on CAM and shows a stronger reduction of tumor mass and microvascular density both in murine syngeneic and xenograft tumor models, compared to the lead compound CA-4P. Altogether, our results indicate that TR-764 is a novel TBA with strong potential as both antivascular and antitumor molecule that could improve the common anticancer therapies, by overcoming hypoxia-induced resistance mechanisms. PMID:27292568

  5. 18{beta}-Glycyrrhetinic acid inhibits adipogenic differentiation and stimulates lipolysis

    SciTech Connect

    Moon, Myung-Hee; Jeong, Jae-Kyo; Lee, You-Jin; Seol, Jae-Won; Ahn, Dong-Choon; Kim, In-Shik; Park, Sang-Youel

    2012-04-20

    Highlights: Black-Right-Pointing-Pointer 18{beta}-GA inhibits adipogenic differentiation in 3T3-L1 preadipocytes and stimulates lipolysis in differentiated adipocytes. Black-Right-Pointing-Pointer Anti-adipogenic effect of 18{beta}-GA is caused by down-regulation of PPAR{gamma} and inactivation of Akt signalling. Black-Right-Pointing-Pointer Lipolytic effect of 18{beta}-GA is mediated by up-regulation of HSL, ATGL and perilipin and activation of HSL. -- Abstract: 18{beta}-Glycyrrhetinic acid (18{beta}-GA) obtained from the herb liquorice has various pharmacological properties including anti-inflammatory and anti-bacterial activities. However, potential biological anti-obesity activities are unclear. In this study, novel biological activities of 18{beta}-GA in the adipogenesis of 3T3-L1 preadipocytes and in lipolysis of differentiated adipocytes were identified. Mouse 3T3-L1 cells were used as an in vitro model of adipogenesis and lipolysis, using a mixture of insulin/dexamethasone/3-isobutyl-1-methylxanthine (IBMX) to induce differentiation. The amount of lipid droplet accumulation was determined by an AdipoRed assay. The expression of several adipogenic transcription factors and enzymes was investigated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. 18{beta}-GA dose-dependently (1-40 {mu}M) significantly decreased lipid accumulation in maturing preadipocytes. In 3T3-L1 preadipocytes, 10 {mu}M of 18{beta}-GA down-regulated the transcriptional levels of the peroxisome proliferator-activated receptor {gamma}, CCAAT/enhancer-binding protein {alpha} and adiponectin, which are markers of adipogenic differentiation via Akt phosphorylation. Also, in differentiated adipocytes, 18{beta}-GA increased the level of glycerol release and up-regulated the mRNA of hormone-sensitive lipase, adipose TG lipase and perilipin, as well as the phosphorylation of hormone-sensitive lipase at Serine 563. The results indicate that 18{beta

  6. Growth Inhibition and Stimulation of Shewanella oneidensis MR-1 by Surfactants and Calcium Polysulfide

    SciTech Connect

    Bailey, Kathryn L.; Tilton, Fred A.; Jansik, Danielle P.; Ergas, Sarina J.; Marshall, Matthew J.; Miracle, Ann L.; Wellman, Dawn M.

    2012-06-14

    Foam delivery technology (FDT) uses surfactant based foam to immobilize subsurface contaminants in situ. Where traditional approaches are impractical, FDT has the potential to overcome many of the technical challenges facing the remediation of contaminated deep vadose zone environments. However, little is known about the effects these reactive chemicals may have on microorganisms inhabiting the contaminated subsurface. In addition, there are currently no standard assays to assess microbial responses to subsurface remedial treatments while these agents are under development. The objective of this study was to develop a rapid laboratory assay to assess the potential growth inhibition and/or stimulation of microorganisms following exposure to candidate FDT components. Calcium polysulfide (CPS) and several surfactants (i.e. sodium laureth sulfate (SLES), sodium dodecyl sulfate (SDS), cocamidopropyl betaine (CAPB) and NINOL40-CO) have diverse chemistries and are candidate components of FDT. Shewanella oneidensis MR-1 cultures were exposed to a range of concentrations of these chemicals to determine the minimum bactericidal concentration (MBC) and the growth and viability potential of these components. Concentrations of SDS higher than 700 {micro}M were toxic to S. oneidensis MR-1 growth over the course of four days of exposure. The relative acute toxicity order for these compounds was SDS>>CPS>>NINOL40-CO>SLES-CAPB. Dose dependent growth decreases (20 to 100 mM) were observed in the CAPB and SLES treated cultures and both CPS and NINOL 40-CO were toxic at all concentrations tested (1.45 to 7.25 mM CPS). Both SLES (20 to 100 mM) and SDS at lower concentrations (20 to 500 {micro}M) were stimulatory to S. oneidensis MR-1 indicating a capacity to be used as a carbon source. These studies also identified potentially key component characteristics, such as precipitate formation and oxygen availability, which may prove valuable in assessing the response of subsurface

  7. Inhibition of the nuclear import of cubitus interruptus by roadkill in the presence of strong hedgehog signal.

    PubMed

    Seong, Ki-Hyeon; Akimaru, Hiroshi; Dai, Ping; Nomura, Teruaki; Okada, Masahiro; Ishii, Shunsuke

    2010-01-01

    Hedgehog (Hh) signalling plays an important role in various developmental processes by activating the Cubitus interruptus (Ci)/Glioblastoma (Gli) family of transcription factors. In the process of proper pattern formation, Ci activity is regulated by multiple mechanisms, including processing, trafficking, and degradation. However, it remains elusive how Ci distinctly recognizes the strong and moderate Hh signals. Roadkill (Rdx) induces Ci degradation in the anterior region of the Drosophila wing disc. Here, we report that Rdx inhibited Ci activity by two different mechanisms. In the region abutting the anterior/posterior boundary, which receives strong Hh signal, Rdx inhibited the nuclear import of Ci by releasing importin α3 from Ci. In this region, Rdx negatively regulated the expression of transcription factor Knot/Collier. In farther anterior regions receiving moderate levels of Hh signal, Rdx induced Ci degradation, as reported previously. Thus, two different mechanisms by which Rdx negatively regulates Ci may play an important role in the fine-tuning of Hh responses. PMID:21179535

  8. Inhibition of PAF synthesis by stimulated human polymorphonuclear leucocytes with cloricromene, an inhibitor of phospholipase A2 activation.

    PubMed Central

    Ribaldi, E.; Mezzasoma, A. M.; Francescangeli, E.; Prosdocimi, M.; Nenci, G. G.; Goracci, G.; Gresele, P.

    1996-01-01

    1. A phospholipase A2 (PLA2) represents the key enzyme in the remodelling pathway of platelet-activating factor (PAF) synthesis in human polymorphonuclear (PMN) leucocytes. 2. PLA2 activation is also the rate-limiting step for the release of the arachidonic acid utilized for the synthesis of leukotrienes in stimulated leucocytes; however, it is unknown whether the PLA2s involved in the two biosynthetic pathways are identical. 3. Cloricromene (8-monochloro-3-beta-diethylaminoethyl-4-methyl-7-ethoxy- carbonylmethoxy coumarin) is an antithrombotic coumarin derivative which inhibits platelet and leucocyte function and suppresses arachidonic acid liberation by interfering with PLA2 activation. 4. The aim of the present study was to assess whether chloricromene inhibits PAF synthesis by stimulated human polymorphonuclear leucocytes (PMNs). 5. Cloricromene (50-500 microM) inhibited in a concentration-dependent manner the release of PAF, as measured by h.p.l.c. bioassay, from A23187-stimulated PMNs. Significant inhibition (45%) of PAF-release was obtained with 50 microM cloricromene and the IC50 was 85 microM. Mepacrine (500 microM), a non-specific PLA2 inhibitor, strikingly reduced PAF release. 6. The incorporation of [3H]-acetate into [3H]-PAF induced by serum-treated zymosan in human PMNs was also inhibited concentration-dependently by cloricromene, with an IC50 of 105 microM. Mepacrine also suppressed [3H]-acetate incorporation into [3H]-PAF. 7. Cloricromene did not affect the activities of the enzymes involved in PAF-synthesis acetyltransferase or phosphocholine transferase. 8. Our data demonstrate that cloricromene, an inhibitor of PLA2-activation in human leucocytes, reduces the synthesis of PAF by stimulated PMNs. This finding has a twofold implication: the PLA2s (or the mechanisms that regulate their activation) involved in PAF synthesis and arachidonate release in human leucocytes are either identical or else indistinguishable by their sensitivity to cloricromene

  9. Platelet-Derived Growth Factor-Receptor α Strongly Inhibits Melanoma Growth In Vitro and In Vivo1

    PubMed Central

    Faraone, Debora; Aguzzi, Maria Simona; Toietta, Gabriele; Facchiano, Angelo M; Facchiano, Francesco; Magenta, Alessandra; Martelli, Fabio; Truffa, Silvia; Cesareo, Eleonora; Ribatti, Domenico; Capogrossi, Maurizio C; Facchiano, Antonio

    2009-01-01

    Cutaneous melanoma is the most aggressive skin cancer; it is highly metastatic and responds poorly to current therapies. The expression of platelet-derived growth factor receptors (PDGF-Rs) is reported to be reduced in metastatic melanoma compared with benign nevi or normal skin; we then hypothesized that PDGF-Rα may control growth of melanoma cells. We show here that melanoma cells overexpressing PDGF-Rα respond to serum with a significantly lower proliferation compared with that of controls. Apoptosis, cell cycle arrest, pRb dephosphorylation, and DNA synthesis inhibition were also observed in cells overexpressing PDGF-Rα. Proliferation was rescued by PDGF-Rα inhibitors, allowing to exclude nonspecific toxic effects and indicating that PDGF-Rα mediates autocrine antiproliferation signals in melanoma cells. Accordingly, PDGF-Rα was found to mediate staurosporine cytotoxicity. A protein array-based analysis of the mitogen-activated protein kinase pathway revealed that melanoma cells overexpressing PDGF-Rα show a strong reduction of c-Jun phosphorylated in serine 63 and of protein phosphatase 2A/Bα and a marked increase of p38γ, mitogen-activated protein kinase kinase 3, and signal regulatory protein α1 protein expression. In a mouse model of primary melanoma growth, infection with the Ad-vector overexpressing PDGF-Rα reached a significant 70% inhibition of primary melanoma growth (P < .001) and a similar inhibition of tumor angiogenesis. All together, these data demonstrate that PDGF-Rα strongly impairs melanoma growth likely through autocrine mechanisms and indicate a novel endogenous mechanism involved in melanoma control. PMID:19649203

  10. Platelet-derived growth factor-receptor alpha strongly inhibits melanoma growth in vitro and in vivo.

    PubMed

    Faraone, Debora; Aguzzi, Maria Simona; Toietta, Gabriele; Facchiano, Angelo M; Facchiano, Francesco; Magenta, Alessandra; Martelli, Fabio; Truffa, Silvia; Cesareo, Eleonora; Ribatti, Domenico; Capogrossi, Maurizio C; Facchiano, Antonio

    2009-08-01

    Cutaneous melanoma is the most aggressive skin cancer; it is highly metastatic and responds poorly to current therapies. The expression of platelet-derived growth factor receptors (PDGF-Rs) is reported to be reduced in metastatic melanoma compared with benign nevi or normal skin; we then hypothesized that PDGF-Ralpha may control growth of melanoma cells. We show here that melanoma cells overexpressing PDGF-Ralpha respond to serum with a significantly lower proliferation compared with that of controls. Apoptosis, cell cycle arrest, pRb dephosphorylation, and DNA synthesis inhibition were also observed in cells overexpressing PDGF-Ralpha. Proliferation was rescued by PDGF-Ralpha inhibitors, allowing to exclude nonspecific toxic effects and indicating that PDGF-Ralpha mediates autocrine antiproliferation signals in melanoma cells. Accordingly, PDGF-Ralpha was found to mediate staurosporine cytotoxicity. A protein array-based analysis of the mitogen-activated protein kinase pathway revealed that melanoma cells overexpressing PDGF-Ralpha show a strong reduction of c-Jun phosphorylated in serine 63 and of protein phosphatase 2A/Balpha and a marked increase of p38gamma, mitogen-activated protein kinase kinase 3, and signal regulatory protein alpha1 protein expression. In a mouse model of primary melanoma growth, infection with the Ad-vector overexpressing PDGF-Ralpha reached a significant 70% inhibition of primary melanoma growth (P < .001) and a similar inhibition of tumor angiogenesis. All together, these data demonstrate that PDGF-Ralpha strongly impairs melanoma growth likely through autocrine mechanisms and indicate a novel endogenous mechanism involved in melanoma control. PMID:19649203

  11. Modified natural porcine surfactant inhibits superoxide anions and proinflammatory mediators released by resting and stimulated human monocytes.

    PubMed

    Walti, H; Polla, B S; Bachelet, M

    1997-01-01

    Pulmonary surfactant has a potential role in modulating inflammation in normal and injured lungs. In lung injury, monocytes become activated and participate in lung inflammation. We therefore, investigated the proinflammatory functions of stimulated human blood monocytes after an overnight preincubation period with modified natural porcine surfactant (Curosurf) (500-1000 micrograms/mL). Monocytes were stimulated either with phorbol myristate acetate (PMA), bacterial extract OM-85, lipopolysaccharide (LPS), or Ca2+ ionophore A23187. The present study shows that Curosurf significantly inhibits: 1) the production of superoxide anions stimulated with OM-85 (1 mg/mL, 30 min), but not with PMA (100 ng/mL, 30 min); 2) the release of cyclooxygenase metabolites prostaglandin E2 and thromboxane B2 stimulated with OM-85 (1 mg/mL, overnight); 3) the release of lipoxygenase metabolite leukotriene C4 stimulated with A23187 (10 microM, 10 min); 4) the release of the cytokine TNF-alpha stimulated overnight with either OM-85 (1 mg/mL) or LPS (10 micrograms/mL)) in a dose-dependent fashion. In addition, Curosurf decreases the spontaneous adherence of monocytes to plastic culture wells in a dose-dependent fashion. Experiments performed with staurosporine, an inhibitor of protein kinase C (PKC) indicate that, in contrast with PMA, the production of superoxide anions stimulated by OM-85 is not related to PKC activation. Consequently, we propose that the mechanism involved in the suppressive effects of Curosurf is PKC-independent. In summary, the present study provides experimental evidence that favors the anti-inflammatory role of modified natural porcine surfactant (Curosurf) in human monocytes in vitro. PMID:8979299

  12. Cortisol Stimulates Secretion of Dehydroepiandrosterone in Human Adrenocortical Cells Through Inhibition of 3βHSD2

    PubMed Central

    Topor, Lisa Swartz; Asai, Masato; Dunn, James; Majzoub, Joseph A.

    2011-01-01

    Context: Initiating factors leading to production of adrenal androgens are poorly defined. Cortisol is present in high concentrations within the adrenal gland, and its production rises with growth during childhood. Objective: Our aim was to characterize the effect of cortisol and other glucocorticoids on androgen secretion from a human adrenocortical cell line and from nonadrenal cells transfected with CYP17A1 or HSD3B2. Design/Setting: This study was performed in cultured cells, at an academic medical center. Methods: The effects of cortisol upon steroid production in human adrenal NCI-H295R cells were measured by immunoassay, tandem mass spectrometry, and thin-layer chromatography. The effects of cortisol upon the activities of 17, 20 lyase and 3βHSD2 were measured in NCI-H295R cells and in transfected COS-7 cells. Results: Cortisol markedly and rapidly stimulated dehydroepiandrosterone (DHEA) in a dose-dependent manner at cortisol concentrations ≥50 μm. Cortisone and 11-deoxycortisol were also potent stimulators of DHEA secretion, whereas prednisolone and dexamethasone were not. Treatment with cortisol did not affect expression of CYP17A1 or HSD3B2 mRNAs. Stimulation of DHEA secretion by cortisol was associated with competitive inhibition of 3βHSD2 activity. Conclusions: Cortisol inhibits 3βHSD2 activity in adrenal cells and in COS-7 cells transfected with HSD3B2. Thus, it is possible that intraadrenal cortisol may participate in the regulation of adrenal DHEA secretion through inhibition of 3βHSD2. We hypothesize that a rise in intraadrenal cortisol during childhood growth may lead to inhibition of 3βHSD2 activity and contribute to the initiation of adrenarche. PMID:20943790

  13. Dual action (stimulation, inhibition) of D600 on contractility and calcium channels in guinea-pig and cat heart cells.

    PubMed Central

    McDonald, T; Pelzer, D; Trautwein, W

    1989-01-01

    1. We examined the effects of D600 (0.2-40 microM, generally 2 microM) on the following (i) developed tension in guinea-pig papillary muscles, (ii) calcium current (Ica) and tension in cat ventricular muscle strands, (iii) Ica in guinea-pig and cat ventricular myocytes, (iv) single Ca2+ channel currents carried by Ba2+ in cell-attached membrane patches of guinea-pig ventricular myocytes, and (v) Ba2+ currents through dihydropyridine (DHP)-binding sites (skeletal muscle) reconstituted into single functional Ca2+ channels in lipid bilayers. 2. In 27 of 140 preparations studied, D600 elicited a transient stimulation that preceded marked inhibition. The stimulation was normally of short duration (less than 5 min) and moderate strength (less than 50% increase). 3. D600 had no effect on the unit conductance of single cardiac Ca2+ channels. Stimulation was characterized by a decrease in the number of records with no openings (blanks) and an increase in the open-state probability of non-blanks (longer open times, shorter closed times). Inhibition began with an increase in the number of blanks and later included a curtailment of open times and a prolongation of closed times. The net effect after 9 min D600 was a 75% reduction in average current amplitude. 4. A similar pattern of changes in channel open and closed times produced enhancement and then depression of time-averaged open-state probability in single reconstituted channels. 5. Single Ca2+ channel current that was stimulated by adrenaline was only slightly depressed after 2 microM-D600 for 30 min. It may be that channel phosphorylation or Gs-protein activation following beta-receptor stimulation reduces channel affinity for D600. 6. Short-lived binding of D600 to a single inhibitory site may enhance association/activation of Gs-protein and thereby cause transient up-regulation prior to increased drug occupancy and inhibition. Alternatively, there may be separate stimulatory and inhibitory sites. One aspect of

  14. Double-Cone Coil TMS Stimulation of the Medial Cortex Inhibits Central Pain Habituation

    PubMed Central

    Mingolla, Arianna; Caroppo, Paola; Orsi, Laura; Mortara, Paolo; Troni, Walter; Pinessi, Lorenzo

    2015-01-01

    Objective The aim of this study was to investigate whether Transcranial Magnetic Stimulation (TMS) applied over the medial line of the scalp affects the subjective perception of continuous pain induced by means of electric stimulation. In addition, we wanted to identify the point of stimulation where this effect was maximum. Methods Superficial electrical stimulation was used to induce continuous pain on the dominant hand. At the beginning of the experiment we reached a pain rating of 5 on an 11-point numeric rating scale (NRS; 0 = no pain and 10 = maximum tolerable pain) for each subject by setting individually the current intensity. The TMS (five pulses at increasing intensities) was applied on 5 equidistant points (one per session) over the medial line of the scalp in 13 healthy volunteers using a double-cone coil to stimulate underlying parts of the brain cortex. In every experimental session the painful stimulation lasted 45 minutes, during which pain and distress intensities NRS were recorded continuously. We calculated the effect of adaptation and the immediate effect of the TMS stimulation for all locations. Additionally, an ALE (Activation Likelihood Estimation) meta-analysis was performed to compare our results with the neuroimaging literature on subjective pain rating. Results TMS stimulation temporarily decreased the pain ratings, and pain adaptation was suppressed when applying the TMS over the FCz site on the scalp. No effect was found for distress ratings. Conclusions The present data suggest that the medial cortex in proximity of the cingulated gyrus has a causal role in adaptation mechanisms and in processing ongoing pain and subjective sensation of pain intensity. PMID:26046985

  15. Theta Burst Stimulation of the Cerebellum Modifies the TMS-Evoked N100 Potential, a Marker of GABA Inhibition

    PubMed Central

    2015-01-01

    Theta burst stimulation (TBS) of the cerebellum, a potential therapy for neurological disease, can modulate corticospinal excitability via the dentato-thalamo-cortical pathway, but it is uncertain whether its effects are mediated via inhibitory or facilitatory networks. The aim of this study was to investigate the effects of 30Hz cerebellar TBS on the N100 waveform of the TMS-evoked potential (TEP), a marker of intracortical GABAB-mediated inhibition. 16 healthy participants (aged 18–30 years; 13 right handed and 3 left handed) received 30Hz intermittent TBS (iTBS), continuous TBS (cTBS) or sham stimulation over the right cerebellum, in three separate sessions. The first 8 participants received TBS at a stimulus intensity of 80% of active motor threshold (AMT), while the remainder received 90% of AMT. Motor evoked potentials (MEP) and TEP were recorded before and after each treatment, by stimulating the first dorsal interosseus area of the left motor cortex. Analysis of the 13 right handed participants showed that iTBS at 90% of AMT increased the N100 amplitude compared to sham and cTBS, without significantly altering MEP amplitude. cTBS at 80% of active motor threshold decreased the N100 amplitude and cTBS overall reduced resting MEP amplitude. The study demonstrates effects of 30Hz cerebellar TBS on inhibitory cortical networks that may be useful for treatment of neurological conditions associated with dysfunctional intracortical inhibition. PMID:26529225

  16. Selective inhibition in children with attention-deficit hyperactivity disorder off and on stimulant medication.

    PubMed

    Bedard, Anne-Claude; Ickowicz, Abel; Logan, Gordon D; Hogg-Johnson, Sheilah; Schachar, Russell; Tannock, Rosemary

    2003-06-01

    Selective inhibition requires discrimination between auditory signals and is assessed using a modification of the stop-signal task. Selective inhibition was assessed in a group of 59 clinic-referred, DSM-IV-diagnosed children with attention-deficit hyperactivity disorder (ADHD) and compared to that of a community sample of 59 children. Methylphenidate (MPH) effects on selective inhibition were assessed in a subset of the ADHD sample that participated in an acute, randomized, placebo-controlled, crossover trial with 3 fixed doses of MPH. Children with ADHD performed more poorly than controls on the majority of selective stop-signal task parameters: they exhibited more anticipatory (invalid) responses, with less accurate and more variable responses on the response execution task, as well as a slower selective inhibition process. MPH improved speed of both inhibition and response execution processes; it also reduced variability of response execution and decreased nonselective inhibition. On the one hand, findings are consistent with purported inhibition deficit in ADHD, but on the other hand, suggest that neither the impairment itself, nor MPH effects, were restricted to inhibition. PMID:12774864

  17. Methadone but not morphine inhibits lubiprostone-stimulated Cl- currents in T84 intestinal cells and recombinant human ClC-2, but not CFTR Cl- currents.

    PubMed

    Cuppoletti, John; Chakrabarti, Jayati; Tewari, Kirti; Malinowska, Danuta H

    2013-05-01

    In clinical trials, methadone, but not morphine, appeared to prevent beneficial effects of lubiprostone, a ClC-2 Cl(-) channel activator, on opioid-induced constipation. Effects of methadone and morphine on lubiprostone-stimulated Cl(-) currents were measured by short circuit current (Isc) across T84 cells. Whole cell patch clamp of human ClC-2 (hClC-2) stably expressed in HEK293 cells and in a high expression cell line (HEK293EBNA) as well as human CFTR (hCFTR) stably expressed in HEK293 cells was used to study methadone and morphine effects on recombinant hClC-2 and hCFTR Cl(-) currents. Methadone but not morphine inhibited lubiprostone-stimulated Isc in T84 cells with half-maximal inhibition at 100 nM. Naloxone did not affect lubiprostone stimulation or methadone inhibition of Isc. Lubiprostone-stimulated Cl(-) currents in hClC-2/HEK293 cells, but not forskolin/IBMX-stimulated Cl(-) currents in hCFTR/HEK293 cells, were inhibited by methadone, but not morphine. HEK293EBNA cells expressing hClC-2 showed time-dependent, voltage-activated, CdCl2-inhibited Cl(-) currents in the absence (control) and the presence of lubiprostone. Methadone, but not morphine, inhibited control and lubiprostone-stimulated hClC-2 Cl(-) currents with half-maximal inhibition at 100 and 200-230 nM, respectively. Forskolin/IBMX-stimulated hClC-2 Cl(-) currents were also inhibited by methadone. Myristoylated protein kinase inhibitor (a specific PKA inhibitor) inhibited forskolin/IBMX- but not lubiprostone-stimulated hClC-2 Cl(-) currents. Methadone caused greater inhibition of lubiprostone-stimulated currents added before patching (66.1 %) compared with after patching (28.7 %). Methadone caused inhibition of lubiprostone-stimulated Cl(-) currents in T84 cells and control; lubiprostone- and forskolin/IBMX-stimulated recombinant hClC-2 Cl(-) currents may be the basis for reduced efficacy of lubiprostone in methadone-treated patients. PMID:22918821

  18. Identification of hop polyphenolic components which inhibit prostaglandin E2 production by gingival epithelial cells stimulated with periodontal pathogen.

    PubMed

    Inaba, Hiroaki; Tagashira, Motoyuki; Honma, Daiki; Kanda, Tomomasa; Kou, Yurong; Ohtake, Yasuyuki; Amano, Atsuo

    2008-03-01

    Chronic marginal periodontitis is a destructive inflammatory disease caused by an imbalance between bacterial virulence and host defense ability, resulting in eventual tooth exfoliation. Porphyromonas gingivalis, a major periodontal pathogen, triggers a series of cellular inflammatory responses including the production of prostaglandin E2 (PGE2), which causes periodontal destruction; thus, anti-inflammatory reagents are considered beneficial for periodontal therapy. In the present study, we examined whether hop- and apple-derived polyphenols (HBP and ACT, respectively) inhibit PGE2 production by human gingival epithelial (HGE) cells stimulated with P. gingivalis components. HGE cells were stimulated with P. gingivalis membrane vesicles, and the effects of HBP, ACT and epigallocatechin gallate (EGCg) on PGE2 production by HGE cells were evaluated using an enzyme-linked immunosorbent assay. HBP and EGCg significantly inhibited PGE2 production, whereas ACT did not. By further fractionation steps of HBP to identify the effective components, 3 components of HBP, 2-[(2-methylpropanoyl)-phloroglucinol]1-O-beta-D-glucopyranoside (MPPG), quercetin 3-O-beta-D-glucopyranoside (isoquercitrin), and kaempferol 3-O-beta-glucopyranoside (astragalin), were found to be elements which significantly inhibited cellular PGE2 production. These results suggest that HBP is a potent inhibitor of cellular PGE2 production induced by P. gingivalis, and HBP may be useful for the prevention and attenuation of periodontitis. PMID:18310924

  19. Melatonin Inhibits CXCL10 and MMP-1 Production in IL-1β-Stimulated Human Periodontal Ligament Cells.

    PubMed

    Hosokawa, Ikuko; Hosokawa, Yoshitaka; Shindo, Satoru; Ozaki, Kazumi; Matsuo, Takashi

    2016-08-01

    Melatonin is a hormone that is mainly secreted by the pineal gland and exhibits a wide spectrum of activities, including antioxidant functions. Melatonin has been detected in gingival crevicular fluid. However, the role of melatonin in periodontal tissue is still uncertain. The aim of this study was to examine the effects of melatonin on inflammatory mediator expression in human periodontal ligament cells (HPDLC). Interleukin (IL)-1β induced CXC chemokine ligand (CXCL)10, matrix metalloproteinase (MMP)-1, and tissue inhibitors of metalloproteinase (TIMP)-1 production in HPDLC. Melatonin decreased CXCL10 and MMP-1 production and increased TIMP-1 production in IL-1β-stimulated HPDLC. Western blot analysis showed that melatonin inhibited p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase (JNK) phosphorylation, and IkB-α degradation and phosphorylation in IL-1β-stimulated HPDLC. These results suggest that melatonin might inhibit Th1 cell migration by reducing CXCL10 production. Moreover, melatonin might inhibit soft tissue destruction by decreasing MMP-1 production in periodontal lesions. PMID:27271323

  20. Delta- and gamma-tocotrienol isomers are potent in inhibiting inflammation and endothelial activation in stimulated human endothelial cells

    PubMed Central

    Muid, Suhaila; Froemming, Gabriele R. Anisah; Rahman, Thuhairah; Ali, A. Manaf; Nawawi, Hapizah M.

    2016-01-01

    Background Tocotrienols (TCTs) are more potent antioxidants than α-tocopherol (TOC). However, the effectiveness and mechanism of the action of TCT isomers as anti-atherosclerotic agents in stimulated human endothelial cells under inflammatory conditions are not well established. Aims 1) To compare the effects of different TCT isomers on inflammation, endothelial activation, and endothelial nitric oxide synthase (eNOS). 2) To identify the two most potent TCT isomers in stimulated human endothelial cells. 3) To investigate the effects of TCT isomers on NFκB activation, and protein and gene expression levels in stimulated human endothelial cells. Methods Human umbilical vein endothelial cells were incubated with various concentrations of TCT isomers or α-TOC (0.3–10 µM), together with lipopolysaccharides for 16 h. Supernatant cells were collected and measured for protein and gene expression of cytokines (interleukin-6, or IL-6; tumor necrosis factor-alpha, or TNF-α), adhesion molecules (intercellular cell adhesion molecule-1, or ICAM-1; vascular cell adhesion molecule-1, or VCAM-1; and e-selectin), eNOS, and NFκB. Results δ-TCT is the most potent TCT isomer in the inhibition of IL-6, ICAM-1, VCAM-1, and NFκB, and it is the second potent in inhibiting e-selectin and eNOS. γ-TCT isomer is the most potent isomer in inhibiting e-selectin and eNOS, and it is the second most potent in inhibiting is IL-6, VCAM-1, and NFκB. For ICAM-1 protein expression, the most potent is δ-TCT followed by α-TCT. α- and β-TCT inhibit IL-6 at the highest concentration (10 µM) but enhance IL-6 at lower concentrations. γ-TCT markedly increases eNOS expression by 8–11-fold at higher concentrations (5–10 µM) but exhibits neutral effects at lower concentrations. Conclusion δ- and γ-TCT are the two most potent TCT isomers in terms of the inhibition of inflammation and endothelial activation whilst enhancing eNOS, possibly mediated via the NFκB pathway. Hence, there is a

  1. Protein ingestion acutely inhibits insulin-stimulated muscle carnitine uptake in healthy young men1

    PubMed Central

    Shannon, Chris E; Nixon, Aline V; Greenhaff, Paul L; Stephens, Francis B

    2016-01-01

    Background: Increasing skeletal muscle carnitine content represents an appealing intervention in conditions of perturbed lipid metabolism such as obesity and type 2 diabetes but requires chronic l-carnitine feeding on a daily basis in a high-carbohydrate beverage. Objective: We investigated whether whey protein ingestion could reduce the carbohydrate load required to stimulate insulin-mediated muscle carnitine accretion. Design: Seven healthy men [mean ± SD age: 24 ± 5 y; body mass index (in kg/m2): 23 ± 3] ingested 80 g carbohydrate, 40 g carbohydrate + 40 g protein, or control (flavored water) beverages 60 min after the ingestion of 4.5 g l-carnitine tartrate (3 g l-carnitine; 0.1% 2[H]3-l-carnitine). Serum insulin concentration, net forearm carnitine balance (NCB; arterialized-venous and venous plasma carnitine difference × brachial artery flow), and carnitine disappearance (Rd) and appearance (Ra) rates were determined at 20-min intervals for 180 min. Results: Serum insulin and plasma flow areas under the curve (AUCs) were similarly elevated by carbohydrate [4.5 ± 0.8 U/L · min (P < 0.01) and 0.5 ± 0.6 L (P < 0.05), respectively] and carbohydrate+protein [3.8 ± 0.6 U/L · min (P < 0.01) and 0.4 ± 0.6 L (P = 0.05), respectively] consumption, respectively, compared with the control visit (0.04 ± 0.1 U/L · min and −0.5 ± 0.2 L). Plasma carnitine AUC was greater after carbohydrate+protein consumption (3.5 ± 0.5 mmol/L · min) than after control and carbohydrate visits [2.1 ± 0.2 mmol/L · min (P < 0.05) and 1.9 ± 0.3 mmol/L · min (P < 0.01), respectively]. NCB AUC with carbohydrate (4.1 ± 3.1 μmol) was greater than during control and carbohydrate-protein visits (−8.6 ± 3.0 and −14.6 ± 6.4 μmol, respectively; P < 0.05), as was Rd AUC after carbohydrate (35.7 ± 25.2 μmol) compared with control and carbohydrate consumption [19.7 ± 15.5 μmol (P = 0.07) and 14.8 ± 9.6 μmol (P < 0.05), respectively]. Conclusions: The insulin

  2. Contribution of opioid and metabotropic glutamate receptor mechanisms to inhibition of bladder overactivity by tibial nerve stimulation.

    PubMed

    Matsuta, Yosuke; Mally, Abhijith D; Zhang, Fan; Shen, Bing; Wang, Jicheng; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2013-07-15

    The contribution of metabotropic glutamate receptors (mGluR) and opioid receptors to inhibition of bladder overactivity by tibial nerve stimulation (TNS) was investigated in cats under α-chloralose anesthesia using LY341495 (a group II mGluR antagonist) and naloxone (an opioid receptor antagonist). Slow infusion cystometry was used to measure the volume threshold (i.e., bladder capacity) for inducing a large bladder contraction. After measuring the bladder capacity during saline infusion, 0.25% acetic acid (AA) was infused to irritate the bladder, activate the nociceptive C-fiber bladder afferents, and induce bladder overactivity. AA significantly (P < 0.0001) reduced bladder capacity to 26.6 ± 4.7% of saline control capacity. TNS (5 Hz, 0.2 ms) at 2 and 4 times the threshold (T) intensity for inducing an observable toe movement significantly increased bladder capacity to 62.2 ± 8.3% at 2T (P < 0.01) and 80.8 ± 9.2% at 4T (P = 0.0001) of saline control capacity. LY341495 (0.1-5 mg/kg iv) did not change bladder overactivity, but completely suppressed the inhibition induced by TNS at a low stimulus intensity (2T) and partially suppressed the inhibition at high intensity (4T). Following administration of LY341495, naloxone (0.01 mg/kg iv) completely eliminated the high-intensity TNS-induced inhibition. However, without LY341495 treatment a 10 times higher dose (0.1 mg/kg) of naloxone was required to completely block TNS inhibition. These results indicate that interactions between group II mGluR and opioid receptor mechanisms contribute to TNS inhibition of AA-induced bladder overactivity. Understanding neurotransmitter mechanisms underlying TNS inhibition of bladder overactivity is important for the development of new treatments for bladder disorders. PMID:23576608

  3. Strychnine blockade of the non-reciprocal inhibition of trigeminal motoneurons induced by stimulation of the parvocellular reticular formation.

    PubMed

    Castillo, P; Pedroarena, C; Chase, M H; Morales, F R

    1991-12-20

    Stimulation of a region within the parvocellular medullary reticular formation (PcRF) that contains somas of premotor interneurons produces short latency inhibitory synaptic potentials (IPSPs) in cat trigeminal motoneurons. The present study was undertaken to determine whether glycinergic synapses are responsible for these IPSPs. The intravenous administration of strychnine, an established glycine antagonist, abolished these PcRF-IPSPs. This effect appears to be specific for glycinergic inhibitory synapses because the short lasting component of the IPSP produced by inferior alveolar nerve (IAN) stimulation was also abolished, whereas, in contrast, the long lasting non-glycinergic component of this IPSP was not suppressed. These results indicate that a glycinergic system in the reticular formation is responsible for the non-reciprocal postsynaptic inhibition of trigeminal motoneurons. PMID:1817740

  4. Chronic ethanol inhibits receptor-stimulated phosphoinositide hydrolysis in rat liver slices

    SciTech Connect

    Gonzales, R.A.; Crews, F.T. )

    1991-03-01

    The effects of chronic ethanol feeding on norepinephrine (NE)- and arginine-vasopressin (AVP)-stimulated phosphoinositide (PI) hydrolysis in rat liver slices was determined. The maximum NE-stimulated PI response was significantly reduced by 40% in liver slices from 8-month-old rats which had been treated for 5 months with a liquid diet containing ethanol compared to pair-fed controls. The maximum AVP-stimulated PI response was decreased by 39% in liver slices from the ethanol-fed rats compared to control. EC50 values for NE- and AVP-stimulated PI hydrolysis in liver slices were not affected by the chronic ethanol treatment. Similar reductions in the maximal NE- and AVP-stimulated PI hydrolysis (28% and 27%, respectively) were found in 22-month-old rats which had been maintained on an ethanol containing diet for 5 months compared to pair-fed controls. The binding of (3H)prazosin and (3H)AVP to liver plasma membranes from 8-month-old ethanol-fed rats was not significantly different from binding to liver membranes from sucrose-fed controls. Our data suggest that chronic ethanol ingestion may lead to a reduction in PI-linked signal transduction in liver.

  5. The Shewanella algae strain YM8 produces volatiles with strong inhibition activity against Aspergillus pathogens and aflatoxins

    PubMed Central

    Gong, An-Dong; Li, He-Ping; Shen, Lu; Zhang, Jing-Bo; Wu, Ai-Bo; He, Wei-Jie; Yuan, Qing-Song; He, Jing-De; Liao, Yu-Cai

    2015-01-01

    Aflatoxigenic Aspergillus fungi and associated aflatoxins are ubiquitous in the production and storage of food/feed commodities. Controlling these microbes is a challenge. In this study, the Shewanella algae strain YM8 was found to produce volatiles that have strong antifungal activity against Aspergillus pathogens. Gas chromatography-mass spectrometry profiling revealed 15 volatile organic compounds (VOCs) emitted from YM8, of which dimethyl trisulfide was the most abundant. We obtained authentic reference standards for six of the VOCs; these all significantly reduced mycelial growth and conidial germination in Aspergillus; dimethyl trisulfide and 2,4-bis(1,1-dimethylethyl)-phenol showed the strongest inhibitory activity. YM8 completely inhibited Aspergillus growth and aflatoxin biosynthesis in maize and peanut samples stored at different water activity levels, and scanning electron microscopy revealed severely damaged conidia and a complete lack of mycelium development and conidiogenesis. YM8 also completely inhibited the growth of eight other agronomically important species of phytopathogenic fungi: A. parasiticus, A. niger, Alternaria alternate, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Monilinia fructicola, and Sclerotinia sclerotiorum. This study demonstrates the susceptibility of Aspergillus and other fungi to VOCs from marine bacteria and indicates a new strategy for effectively controlling these pathogens and the associated mycotoxin production during storage and possibly in the field. PMID:26500631

  6. The Shewanella algae strain YM8 produces volatiles with strong inhibition activity against Aspergillus pathogens and aflatoxins.

    PubMed

    Gong, An-Dong; Li, He-Ping; Shen, Lu; Zhang, Jing-Bo; Wu, Ai-Bo; He, Wei-Jie; Yuan, Qing-Song; He, Jing-De; Liao, Yu-Cai

    2015-01-01

    Aflatoxigenic Aspergillus fungi and associated aflatoxins are ubiquitous in the production and storage of food/feed commodities. Controlling these microbes is a challenge. In this study, the Shewanella algae strain YM8 was found to produce volatiles that have strong antifungal activity against Aspergillus pathogens. Gas chromatography-mass spectrometry profiling revealed 15 volatile organic compounds (VOCs) emitted from YM8, of which dimethyl trisulfide was the most abundant. We obtained authentic reference standards for six of the VOCs; these all significantly reduced mycelial growth and conidial germination in Aspergillus; dimethyl trisulfide and 2,4-bis(1,1-dimethylethyl)-phenol showed the strongest inhibitory activity. YM8 completely inhibited Aspergillus growth and aflatoxin biosynthesis in maize and peanut samples stored at different water activity levels, and scanning electron microscopy revealed severely damaged conidia and a complete lack of mycelium development and conidiogenesis. YM8 also completely inhibited the growth of eight other agronomically important species of phytopathogenic fungi: A. parasiticus, A. niger, Alternaria alternate, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Monilinia fructicola, and Sclerotinia sclerotiorum. This study demonstrates the susceptibility of Aspergillus and other fungi to VOCs from marine bacteria and indicates a new strategy for effectively controlling these pathogens and the associated mycotoxin production during storage and possibly in the field. PMID:26500631

  7. Potassium uptake supporting plant growth in the absence of AKT1 channel activity: Inhibition by ammonium and stimulation by sodium

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Hirsch, R. E.; Lewis, D. R.; Qi, Z.; Sussman, M. R.; Lewis, B. D.

    1999-01-01

    A transferred-DNA insertion mutant of Arabidopsis that lacks AKT1 inward-rectifying K+ channel activity in root cells was obtained previously by a reverse-genetic strategy, enabling a dissection of the K+-uptake apparatus of the root into AKT1 and non-AKT1 components. Membrane potential measurements in root cells demonstrated that the AKT1 component of the wild-type K+ permeability was between 55 and 63% when external [K+] was between 10 and 1,000 microM, and NH4+ was absent. NH4+ specifically inhibited the non-AKT1 component, apparently by competing for K+ binding sites on the transporter(s). This inhibition by NH4+ had significant consequences for akt1 plants: K+ permeability, 86Rb+ fluxes into roots, seed germination, and seedling growth rate of the mutant were each similarly inhibited by NH4+. Wild-type plants were much more resistant to NH4+. Thus, AKT1 channels conduct the K+ influx necessary for the growth of Arabidopsis embryos and seedlings in conditions that block the non-AKT1 mechanism. In contrast to the effects of NH4+, Na+ and H+ significantly stimulated the non-AKT1 portion of the K+ permeability. Stimulation of akt1 growth rate by Na+, a predicted consequence of the previous result, was observed when external [K+] was 10 microM. Collectively, these results indicate that the AKT1 channel is an important component of the K+ uptake apparatus supporting growth, even in the "high-affinity" range of K+ concentrations. In the absence of AKT1 channel activity, an NH4+-sensitive, Na+/H+-stimulated mechanism can suffice.

  8. CPAP inhibits non-nutritive swallowing through stimulation of bronchopulmonary receptors.

    PubMed

    Samson, Nathalie; Duvareille, Charles; St-Hilaire, Marie; Clapperton, Véronique; Praud, Jean-Paul

    2008-01-01

    While swallowing and respiratory problems are among the most frequent disorders encountered in neonates, the interrelationships between both functions are not completely understood. This is especially true for non-nutritive swallowing (NNS), which fulfills the important function of clearing upper airways from both local secretions and liquids refluxed from the stomach. Recently, we showed that nasal CPAP inhibits NNS during quiet sleep in the newborn lamb (Samson, St-Hilaire, Nsegbe, Reix, Moreau-Bussière and Praud 2005). The present study was aimed at testing the hypothesis that NNS inhibition is eliminated when CPAP is directly administered through a tracheostomy, thus eliminating reflexes originating from upper airway receptors. Results show that both nasal and tracheal CPAP 6cm H2O similarly inhibit total NNS during quiet sleep, thus suggesting that the inhibiting effect of nasal CPAP on NNS is mainly mediated through bronchopulmonary mechanical receptors with minimal participation of the upper airways. PMID:18085310

  9. Ethanol and Other Short-Chain Alcohols Inhibit NLRP3 Inflammasome Activation through Protein Tyrosine Phosphatase Stimulation.

    PubMed

    Hoyt, Laura R; Ather, Jennifer L; Randall, Matthew J; DePuccio, Daniel P; Landry, Christopher C; Wewers, Mark D; Gavrilin, Mikhail A; Poynter, Matthew E

    2016-08-15

    Immunosuppression is a major complication of alcoholism that contributes to increased rates of opportunistic infections and sepsis in alcoholics. The NLRP3 inflammasome, a multiprotein intracellular pattern recognition receptor complex that facilitates the cleavage and secretion of the proinflammatory cytokines IL-1β and IL-18, can be inhibited by ethanol, and we sought to better understand the mechanism through which this occurs and whether chemically similar molecules exert comparable effects. We show that ethanol can specifically inhibit activation of the NLRP3 inflammasome, resulting in attenuated IL-1β and caspase-1 cleavage and secretion, as well as diminished apoptosis-associated speck-like protein containing a CARD (ASC) speck formation, without affecting potassium efflux, in a mouse macrophage cell line (J774), mouse bone marrow-derived dendritic cells, mouse neutrophils, and human PBMCs. The inhibitory effects on the Nlrp3 inflammasome were independent of γ-aminobutyric acid A receptor activation or N-methyl-d-asparate receptor inhibition but were associated with decreased oxidant production. Ethanol treatment markedly decreased cellular tyrosine phosphorylation, whereas administration of the tyrosine phosphatase inhibitor sodium orthovanadate prior to ethanol restored tyrosine phosphorylation and IL-1β secretion subsequent to ATP stimulation. Furthermore, sodium orthovanadate-induced phosphorylation of ASC Y144, necessary and sufficient for Nlrp3 inflammasome activation, and secretion of phosphorylated ASC were inhibited by ethanol. Finally, multiple alcohol-containing organic compounds exerted inhibitory effects on the Nlrp3 inflammasome, whereas 2-methylbutane (isopentane), the analogous alkane of the potent inhibitor isoamyl alcohol (isopentanol), did not. Our results demonstrate that ethanol antagonizes the NLRP3 inflammasome at an apical event in its activation through the stimulation of protein tyrosine phosphatases, an effect shared by other

  10. Coptisine from Coptis chinensis inhibits production of inflammatory mediators in lipopolysaccharide-stimulated RAW 264.7 murine macrophage cells.

    PubMed

    Wu, Jiasi; Zhang, Hai; Hu, Boyang; Yang, Lijuan; Wang, Ping; Wang, Fei; Meng, Xianli

    2016-06-01

    Coptis chinensis has been used for the treatment of inflammatory diseases in China and other Asian countries for centuries. However, the chemical constituents and mechanism underlying the anti-inflammatory activity of this medicinal plant are poorly understood. Here, coptisine, the main constituent of C. chinensis, was shown to potently inhibit the production of nitric oxide (NO) by suppressing the protein and mRNA expressions of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Coptisine also inhibited the production of the pro-inflammatory cytokines interleukin-1β (IL-1β) and interleukin-6 (IL-6) by suppressing expression of cytokine mRNA. Coptisine suppressed the degradation of inhibitor of nuclear factor κBα (IκBα) and phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and phosphoinositide 3-kinase/Akt (PI3K/Akt). Coptisine had no effect on the expression of toll-like receptor 4 (TLR-4) and myeloid differentiation factor 88 (MyD88) as well as LPS binding to TLR-4. Coptisine also inhibited carrageenan-elicited rat paw edema and reduced the release of TNF-α and NO in rat inflamed tissue. These results suggest that coptisine inhibits LPS-stimulated inflammation by blocking nuclear factor-kappa B, MAPK, and PI3K/Akt activation in macrophages, and can be used as an agent for the prevention and treatment of inflammatory diseases. PMID:27018392

  11. Relationship between transcranial magnetic stimulation measures of intracortical inhibition and spectroscopy measures of GABA and glutamate+glutamine

    PubMed Central

    Tremblay, Sara; Beaulé, Vincent; Proulx, Sébastien; de Beaumont, Louis; Marjańska, Małgorzata; Doyon, Julien; Pascual-Leone, Alvaro; Lassonde, Maryse

    2013-01-01

    Transcranial magnetic stimulation (TMS) can provide an index of intracortical excitability/inhibition balance. However, the neurochemical substrate of these measures remains unclear. Pharmacological studies suggest the involvement of GABAA and GABAB receptors in TMS protocols aimed at measuring intracortical inhibition, but this link remains inferential. Proton magnetic resonance spectroscopy (1H-MRS) permits measurement of GABA and glutamate + glutamine (Glx) concentrations in the human brain and might help in the direct empirical assessment of the relationship between TMS inhibitory measures and neurotransmitter concentrations. In the present study, MRS-derived relative concentrations of GABA and Glx measured in the left M1 of healthy participants were correlated with TMS measures of intracortical inhibition. Glx levels were found to correlate positively with TMS-induced silent period duration, whereas no correlation was found between GABA concentration and TMS measures. The present data demonstrate that specific TMS measures of intracortical inhibition are linked to shifts in cortical Glx, rather than GABA neurotransmitter levels. Glutamate might specifically interact with GABAB receptors, where higher MRS-derived Glx concentrations seem to be linked to higher levels of receptor activity. PMID:23221412

  12. Inhibition of seed germination by extracts of bitter Hawkesbury watermelon containing cucurbitacin, a feeding stimulant for corn rootworm (Coleoptera: Chrysomelidae).

    PubMed

    Martin, Phyllis A W; Blackburn, Michael

    2003-04-01

    Cucurbitacins are feeding stimulants for corn rootworm used in baits to control the adults of this insect pest. Corn rootworm larvae also feed compulsively on cucurbitacins. Cucurbitacins are reported to be gibberellin antagonists that may preclude their use as seed treatments for these soil-dwelling insects. The crude extract of a bitter Hawkesbury watermelon containing cucurbitacin E-glycoside significantly inhibited germination of watermelon, squash, and tomato seeds. Although the germination of corn seed was not significantly inhibited, root elongation was inhibited by crude extracts, but not by high-performance liquid chromatography-purified cucurbitacin E-glycoside. Therefore, the effects of the major components in the bitter watermelon extract (e.g., sugars) on seed germination and root elongation were determined. Pure sugars (glucose and fructose), at concentrations found in watermelon extract, mimicked the inhibition of seed germination and root elongation seen with the crude bitter Hawkesbury watermelon extract. Removal of these sugars may be necessary to use this extract as a bait for corn rootworm larvae as a seed or root treatment. PMID:14994812

  13. Preconditioning of Microglia by α-Synuclein Strongly Affects the Response Induced by Toll-like Receptor (TLR) Stimulation

    PubMed Central

    Gonzalez-Rey, Elena; Lachaud, Christian C.; Guilliams, Tim; Fernandez-Montesinos, Rafael; Benitez-Rondan, Alicia; Robledo, Gema; Hmadcha, Abdelkrim; Delgado, Mario; Dobson, Christopher M.; Pozo, David

    2013-01-01

    In recent years, it has become accepted that α-synuclein (αSyn) has a key role in the microglia-mediated neuroinflammation, which accompanies the development of Parkinson’s disease and other related disorders, such as Dementia with Lewy Bodies and Alzheimer’s disease. Nevertheless, the cellular and molecular mechanisms underlying its pathological actions, especially in the sporadic forms of the diseases, are not completely understood. Intriguingly, several epidemiological and animal model studies have revealed a link between certain microbial infections and the onset or progression of sporadic forms of these neurodegenerative disorders. In this work, we have characterized the effect of toll-like receptor (TLR) stimulation on primary murine microglial cultures and analysed the impact of priming cells with extracellular wild-type (Wt) αSyn on the subsequent TLR stimulation of cells with a set of TLR ligands. By assaying key interleukins and chemokines we report that specific stimuli, in particular Pam3Csk4 (Pam3) and single-stranded RNA40 (ssRNA), can differentially affect the TLR2/1- and TLR7-mediated responses of microglia when pre-conditioned with αSyn by augmenting IL-6, MCP-1/CCL2 or IP-10/CXCL10 secretion levels. Furthermore, we report a skewing of αSyn-primed microglia stimulated with ssRNA (TLR7) or Pam3 (TLR2/1) towards intermediate but at the same time differential, M1/M2 phenotypes. Finally, we show that the levels and intracellular location of activated caspase-3 protein change significantly in αSyn-primed microglia after stimulation with these particular TLR agonists. Overall, we report a remarkable impact of non-aggregated αSyn pre-sensitization of microglia on TLR-mediated immunity, a phenomenon that could contribute to triggering the onset of sporadic α-synuclein-related neuropathologies. PMID:24236103

  14. Synaptic NMDA receptor stimulation activates PP1 by inhibiting its phosphorylation by Cdk5

    PubMed Central

    Hou, Hailong; Sun, Lu; Siddoway, Benjamin A.; Petralia, Ronald S.; Yang, Hongtian; Gu, Hua; Nairn, Angus C.

    2013-01-01

    The serine/threonine protein phosphatase protein phosphatase 1 (PP1) is known to play an important role in learning and memory by mediating local and downstream aspects of synaptic signaling, but how PP1 activity is controlled in different forms of synaptic plasticity remains unknown. We find that synaptic N-methyl-d-aspartate (NMDA) receptor stimulation in neurons leads to activation of PP1 through a mechanism involving inhibitory phosphorylation at Thr320 by Cdk5. Synaptic stimulation led to proteasome-dependent degradation of the Cdk5 regulator p35, inactivation of Cdk5, and increased auto-dephosphorylation of Thr320 of PP1. We also found that neither inhibitor-1 nor calcineurin were involved in the control of PP1 activity in response to synaptic NMDA receptor stimulation. Rather, the PP1 regulatory protein, inhibitor-2, formed a complex with PP1 that was controlled by synaptic stimulation. Finally, we found that inhibitor-2 was critical for the induction of long-term depression in primary neurons. Our work fills a major gap regarding the regulation of PP1 in synaptic plasticity. PMID:24189275

  15. Subthalamic nucleus high-frequency stimulation generates a concomitant synaptic excitation–inhibition in substantia nigra pars reticulata

    PubMed Central

    Bosch, Clémentine; Degos, Bertrand; Deniau, Jean-Michel; Venance, Laurent

    2011-01-01

    Abstract Deep brain stimulation is an efficient treatment for various neurological pathologies and a promising tool for neuropsychiatric disorders. This is particularly exemplified by high-frequency stimulation of the subthalamic nucleus (STN-HFS), which has emerged as an efficient symptomatic treatment for Parkinson's disease. How STN-HFS works is still not fully elucidated. With dual patch-clamp recordings in rat brain slices, we analysed the cellular responses of STN stimulation on SNr neurons by simultaneously recording synaptic currents and firing activity. We showed that STN-HFS caused an increase of the spontaneous spiking activity in half of SNr neurons while the remaining ones displayed a decrease. At the synaptic level, STN stimulation triggered inward current in 58% of whole-cell recorded neurons and outward current in the remaining ones. Using a pharmacological approach, we showed that STN-HFS-evoked responses were mediated in all neurons by a balance between AMPA/NMDA receptors and GABAA receptors, whose ratio promotes either a net excitation or a net inhibition. Interestingly, we observed a higher excitation occurrence in 6-hydroxydopamine (6-OHDA)-treated rats. In vivo injections of phaseolus revealed that GABAergic pallido-nigral fibres travel through the STN whereas striato-nigral fibres travel below it. Therefore, electrical stimulation of the STN does not only recruit glutamatergic axons from the STN, but also GABAergic passing fibres probably from the globus pallidus. For the first time, we showed that STN-HFS induces concomitant excitatory–inhibitory synaptic currents in SNr neurons by recruitment of efferences and passing fibres allowing a tight control on basal ganglia outflow. PMID:21690190

  16. NS-398, a selective COX-2 inhibitor, inhibits proliferation of IL-1{beta}-stimulated vascular smooth muscle cells by induction of {eta}{omicron}-1

    SciTech Connect

    Choi, Hyoung Chul; Kim, Hee Sun; Lee, Kwang Youn; Chang, Ki Churl Kang, Young Jin

    2008-11-28

    We investigated whether NS-398, a selective inhibitor of COX-2, induces HO-1 in IL-1{beta}-stimulated vascular smooth muscle cells (VSMC). NS-398 reduced the production of PGE{sub 2} without modulation of expression of COX-2 in IL-1{beta}-stimulated VSMC. NS-398 increased HO-1 mRNA and protein in a dose-dependent manner, but inhibited proliferation of IL-1{beta}-stimulated VSMC. Furthermore, SnPPIX, a HO-1 inhibitor, reversed the effects of NS-398 on PGE{sub 2} production, suggesting that COX-2 activity can be affected by HO-1. Hemin, a HO-1 inducer, also reduced the production of PGE{sub 2} and proliferation of IL-1{beta}-stimulated VSMC. CORM-2, a CO-releasing molecule, but not bilirubin inhibited proliferation of IL-1{beta}-stimulated VSMC. NS-398 inhibited proliferation of IL-1{beta}-stimulated VSMC in a HbO{sub 2}-sensitive manner. In conclusion, NS-398 inhibits proliferation of IL-1{beta}-stimulated VSMC by HO-1-derived CO. Thus, NS-398 may facilitate the healing process of vessels in vascular inflammatory disorders such as atherosclerosis.

  17. Stimulated human melanocytes express and release interleukin-8, which is inhibited by luteolin: relevance to early vitiligo

    PubMed Central

    Miniati, A.; Weng, Z.; Zhang, B.; Therianou, A.; Nicolaidou, E.; Stratigos, A. J.; Antoniou, C.; Theoharides, T. C.

    2014-01-01

    Summary Vitiligo is a disorder of depigmentation, for which the pathogenesis is as yet unclear. Interleukin (IL)-8 is a key inflammatory chemokine. We investigated the regulation of IL-8 production in human melanocytes, and the IL-8 serum levels and skin gene expression in patients with vitiligo and in controls. Cultured melanocytes were stimulated for 24 h with tumour necrosis factor (TNF) 100 ng/mL and IL-1β 10 ng/mL, with or without pretreatment with luteolin 50 μmol/L for 30 min, and IL-8 release was measured by ELISA. Serum cytokines were measured by a microbead array. Skin biopsies were taken from healthy subjects (n = 14) as well as from marginal lesional and nonlesional skin from patients with vitiligo (n = 15). IL-8 gene expression was evaluated by quantitative reverse transcriptase PCR. Both TNF and IL-1β stimulated significant IL-8 release (P < 0.01) from melanocytes, whereas pretreatment with luteolin significantly inhibited this effect (P < 0.01). IL-8 gene expression was significantly increased in vitiligo compared with control skin (P < 0.05). IL-8 may be involved in vitiligo inflammation. Inhibition by luteolin of IL-8 release could be useful for vitiligo therapy. PMID:23782102

  18. Stimulated human melanocytes express and release interleukin-8, which is inhibited by luteolin: relevance to early vitiligo.

    PubMed

    Miniati, A; Weng, Z; Zhang, B; Therianou, A; Vasiadi, M; Nicolaidou, E; Stratigos, A J; Antoniou, C; Theoharides, T C

    2014-01-01

    Vitiligo is a disorder of depigmentation, for which the pathogenesis is as yet unclear. Interleukin (IL)-8 (CXCL8) is a key inflammatory chemokine. We investigated the regulation of IL-8 production in human melanocytes, and the IL-8 serum levels and skin gene expression in patients with vitiligo and in controls. Cultured melanocytes were stimulated for 24 h with tumour necrosis factor (TNF) 100 ng/mL and IL-1β 10 ng/mL, with or without pretreatment with luteolin 50 μmol/L for 30 min, and IL-8 release was measured by ELISA. Serum cytokines were measured by a microbead array. Skin biopsies were taken from healthy subjects (n = 14) as well as from marginal lesional and nonlesional skin from patients with vitiligo (n = 15). IL-8 gene expression was evaluated by quantitative real time PCR. Both TNF and IL-1β stimulated significant IL-8 release (P < 0.01) from melanocytes, whereas pretreatment with luteolin significantly inhibited this effect (P < 0.01). IL-8 gene expression was significantly increased in vitiligo compared with control skin (P < 0.05). IL-8 may be involved in vitiligo inflammation. Inhibition by luteolin of IL-8 release could be useful for vitiligo therapy. PMID:23782102

  19. Nitric oxide (NO) inhibits antigen-stimulated increases in vasoconstriction and glycogenolysis in perfused livers derived from sensitized rats

    SciTech Connect

    Hines, K.L.; Bates, J.N.; Fisher, R.A. )

    1991-03-11

    Recent studies in the authors laboratory demonstrated that infusion of antigen into perfused livers from sensitized rats produces increases in hepatic portal pressure, increases in hepatic glucose output and decreases in hepatic oxygen consumption. In the present study, effects of NO on these hepatic responses to antigen challenge were investigated. Infusion of NO into perfused livers from sensitized rats attenuated ovalbumin induced increases in hepatic portal pressure and glucose output approximately 85% and 90%, respectively, and abolished ovalbumin-induced decreases in hepatic oxygen consumption. The duration of ovalbumin-stimulated increases in hepatic portal pressure was reduced nearly 90% by NO. Similarly, infusion of NO into perfused livers from sensitized rats inhibited increases in hepatic portal pressure and glucose output in response to platelet-activating factor (PAF) nearly 80 and 90%, respectively. In contrast, NO inhibited completely hepatic vasoconstriction in response to phenylephrine without altering glycogenolytic responses to this {alpha}-adrenergic agonist. These results provide evidence for regulatory effects of NO on hemodynamic and glycogenolytic responses to antigen in perfused livers from sensitized rats. These observations support previous findings which suggest that hepatic responses to sensitizing antigen may be mediated by PAF or other autacoid mediators which stimulate glycogenolysis in liver by indirect mechanisms involving hepatic vasoconstriction.

  20. Sitagliptin attenuates inflammatory responses in lipopolysaccharide-stimulated cardiomyocytes via nuclear factor-κB pathway inhibition

    PubMed Central

    LIN, CHIEN-HUNG; LIN, CHUNG-CHING

    2016-01-01

    Glucagon-like peptide-1 (GLP-1) and GLP-1 receptors (GLP-1Rs) are responsible for glucose homeostasis, and have been shown to reduce inflammation in preclinical studies. The aim of the present study was to determine whether sitagliptin, an inhibitor of the enzyme dipeptidyl peptidase-4 (DPP-4), as a GLP-1 receptor agonist, exerts an anti-inflammatory effect on cardiomyoblasts during lipopolysaccharide (LPS) stimulation. Exposure to LPS increased the expression levels of tumor necrosis factor (TNF)-α, interleukin-6 (IL)-6 and IL-1β in H9c2 cells, and also resulted in elevations in cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression and nuclear factor-κB (NF-κB) nuclear translocation. Treatment with the DPP-4 inhibitor sitagliptin dose-dependently downregulated the mRNA levels of IL-6, COX-2 and iNOS in LPS-stimulated H9c2 cells. In addition, sitagliptin inhibited the increased protein expression of IL-6, TNF-α and IL-1β. NF-κB mRNA expression was reduced and its translocation to the nucleus was suppressed by treatment with sitagliptin. The present results demonstrated that sitagliptin exerts a beneficial effect on cardiomyoblasts exposed to LPS by inhibiting expression of inflammatory mediators and suppressing NF-κB activation. These findings indicate that the DPP-4 inhibitor sitagliptin may serve a function in cardiac remodeling attributed to sepsis-induced inflammation. PMID:27284355

  1. An Antagonistic Vascular Endothelial Growth Factor (VEGF) Variant Inhibits VEGF-Stimulated Receptor Autophosphorylation and Proliferation of Human Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Siemeister, Gerhard; Schirner, Michael; Reusch, Petra; Barleon, Bernhard; Marme, Dieter; Martiny-Baron, Georg

    1998-04-01

    Vascular endothelial growth factor (VEGF) is a potent mitogen with a unique specificity for endothelial cells and a key mediator of aberrant endothelial cell proliferation and vascular permeability in a variety of human pathological situations, such as tumor angiogenesis, diabetic retinopathy, rheumatoid arthritis, or psoriasis. VEGF is a symmetric homodimeric molecule with two receptor binding interfaces lying on each pole of the molecule. Herein we report on the construction and recombinant expression of an asymmetric heterodimeric VEGF variant with an intact receptor binding interface at one pole and a mutant receptor binding interface at the second pole of the dimer. This VEGF variant binds to VEGF receptors but fails to induce receptor activation. In competition experiments, the heterodimeric VEGF variant antagonizes VEGF-stimulated receptor autophosphorylation and proliferation of endothelial cells. A 15-fold excess of the heterodimer was sufficient to inhibit VEGF-stimulated endothelial cell proliferation by 50%, and a 100-fold excess resulted in an almost complete inhibition. By using a rational approach that is based on the structure of VEGF, we have shown the feasibility to construct a VEGF variant that acts as an VEGF antagonist.

  2. Vagus nerve electrical stimulation inhibits serum levels of S100A8 protein in septic shock rats.

    PubMed

    Lei, Ming; Liu, Xin-Xin

    2016-05-01

    The vagus nerve and the released acetylcholine exert anti-inflammatory effects and inhibit septic shock. However, their detailed mechanisms remain to be elucidated. The present study aimed to investigate the effects of vagus nerve electrical stimulation on serum S100A8 levels in septic shock rats. A total of 36 male Sprague-Dawley rats were randomly divided into six equal groups: i) Sham group, receiving sham operation; ii) CLP group, subjected to cecal ligation and puncture (CLP) to establish a model of polymicrobial sepsis; iii) VGX group, subjected to CLP and bilateral cervical vagotomy; iv) STM group, subjected to CLP, bilateral cervical vagotomy and electrical stimulation on the left vagus nerve trunk; v) α‑bungarotoxin (BGT) group was administered α‑BGT prior to electrical stimulation; vi) Anti‑receptor for advanced glycation end products (RAGE) group, administered intraperitoneal injection of anti‑RAGE antibody prior to electrical stimulation. The right carotid artery was cannulated to monitor mean artery pressure (MAP). The serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured to assess the liver function. Serum S100A8 and advanced glycation end product (AGE) levels were measured using enzyme‑linked immunosorbent assays. The expression of hepatic RAGE was determined by western blotting. The present study revealed that Sprague‑Dawley rats exhibited progressive hypotension and significantly increased serum AST and ALT levels following CLP challenge compared with the sham group. The levels of S100A8 and AGEs, and the protein expression of hepatic RAGE were significantly increased following CLP compared with the sham group. Vagus nerve electrical stimulation significantly prevented the development of CLP‑induced hypotension, alleviated the hepatic damage, reduced serum S100A8 and AGEs production, and reduced the expression of hepatic RAGE. The inhibitory effect of vagus nerve electrical

  3. The influence of bilateral subthalamic nucleus deep brain stimulation on impulsivity and prepulse inhibition in Parkinson’s disease patients

    PubMed Central

    Gee, Lucy; Smith, Heather; Cruz, Priscilla De La; Campbell, Joannalee; Fama, Chris; Haller, Jessica; Ramirez-Zamora, Adolfo; Durphy, Jennifer; Hanspal, Era; Molho, Eric; Barba, Anne; Shin, Damian; Pilitsis, Julie G.

    2015-01-01

    Background At least 14% of Parkinson disease (PD) patients develop impulse control disorders (ICDs). The pathophysiology behind these behaviors and the impact of deep brain stimulation in a real-life setting remains unclear. Objectives We prospectively examined the impact of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) on ICDs in PD patients, as well as the relationship between impaired sensorimotor gaiting and impulsivity. Methods Patients undergoing bilateral STN-DBS were assessed for ICDs preoperatively and 1-year postoperatively using a validated questionnaire (QUIP-RS). A subset of patients completed the Balloon Analog Risk Task (BART) and auditory pre-pulse inhibition (PPI) testing. Results Analysis revealed 12 patients had an improvement in score assessing ICDs (“good responders” – GR; p = 0.006) while 4 had a worse or stable score (“poor responders” – PR; p > 0.05). GR further exemplified a significant decrease in hypersexual behavior (p = 0.005) and binge eating (p = 0.01). Impaired PPI responses also significantly correlated with impulsivity in BART (r = −0.72, p = 0.044). Discussion Following bilateral STN-DBS 75% of our cohort had a reduction in ICDs, thus suggesting deep brain stimulation effectively manages ICDs in PD. The role of impaired PPI in predisposition to ICDs in PD warrants further investigation. PMID:26066569

  4. Factor Xa Inhibitor Suppresses the Release of Phosphorylated HSP27 from Collagen-Stimulated Human Platelets: Inhibition of HSP27 Phosphorylation via p44/p42 MAP Kinase

    PubMed Central

    Tsujimoto, Masanori; Kuroyanagi, Gen; Matsushima-Nishiwaki, Rie; Kito, Yuko; Enomoto, Yukiko; Iida, Hiroki; Ogura, Shinji; Otsuka, Takanobu; Tokuda, Haruhiko; Kozawa, Osamu; Iwama, Toru

    2016-01-01

    Selective inhibitors of factor Xa (FXa) are widely recognized as useful therapeutic tools for stroke prevention in non-valvular atrial fibrillation or venous thrombosis. Thrombin, which is rapidly generated from pro-thrombin through the activation of factor X to FXa, acts as a potent activator of human platelets. Thus, the reduction of thrombin generation by FXa inhibitor eventually causes a suppressive effect on platelet aggregation. However, little is known whether FXa inhibitors directly affect the function of human platelets. We have previously reported that collagen induces the phosphorylation of heat shock protein 27 (HSP27), a low-molecular weight heat shock protein via Rac-dependent activation of p44/p42 mitogen-activated protein (MAP) kinase in human platelets, eventually resulting in the release of HSP27. In the present study, we investigated the direct effect of FXa inhibitor on the collagen-induced human platelet activation. Rivaroxaban as well as edoxaban significantly reduced the collagen-induced phosphorylation of both HSP27 and p44/p42 MAP kinase without affecting the platelet aggregation. Rivaroxaban significantly inhibited the release of phosphorylated HSP27 from collagen-stimulated platelets but not the secretion of platelet derived growth factor-AB. In patients administrated with rivaroxaban, the collagen-induced levels of phosphorylated HSP27 were markedly diminished after 2 days of administration, which failed to affect the platelet aggregation. These results strongly suggest that FXa inhibitor reduces the collagen-stimulated release of phosphorylated HSP27 from human platelets due to the inhibition of HSP27 phosphorylation via p44/p42 MAP kinase. PMID:26867010

  5. Estrogen inhibits RANKL-stimulated osteoclastic differentiation of human monocytes through estrogen and RANKL-regulated interaction of estrogen receptor-{alpha} with BCAR1 and Traf6

    SciTech Connect

    Robinson, Lisa J.; Yaroslavskiy, Beatrice B.; Griswold, Reed D.; Zadorozny, Eva V.; Guo, Lida; Tourkova, Irina L.; Blair, Harry C.

    2009-04-15

    The effects of estrogen on osteoclast survival and differentiation were studied using CD14-selected mononuclear osteoclast precursors from peripheral blood. Estradiol at {approx} 1 nM reduced RANKL-dependent osteoclast differentiation by 40-50%. Osteoclast differentiation was suppressed 14 days after addition of RANKL even when estradiol was withdrawn after 18 h. In CD14+ cells apoptosis was rare and was not augmented by RANKL or by 17-{beta}-estradiol. Estrogen receptor-{alpha} (ER{alpha}) expression was strongly down-regulated by RANKL, whether or not estradiol was present. Mature human osteoclasts thus cannot respond to estrogen via ER{alpha}. However, ER{alpha} was present in CD14+ osteoclast progenitors, and a scaffolding protein, BCAR1, which binds ER{alpha} in the presence of estrogen, was abundant. Immunoprecipitation showed rapid ({approx} 5 min) estrogen-dependent formation of ER{alpha}-BCAR1 complexes, which were increased by RANKL co-treatment. The RANKL-signaling intermediate Traf6, which regulates NF-{kappa}B activity, precipitated with this complex. Reduction of NF-{kappa}B nuclear localization occurred within 30 min of RANKL stimulation, and estradiol inhibited the phosphorylation of I{kappa}B in response to RANKL. Inhibition by estradiol was abolished by siRNA knockdown of BCAR1. We conclude that estrogen directly, but only partially, curtails human osteoclast formation. This effect requires BCAR1 and involves a non-genomic interaction with ER{alpha}.

  6. Inhibition of nitric oxide production in LPS-stimulated RAW 264.7 cells by stem bark of Ulmus pumila L.

    PubMed Central

    Joo, Taewoo; Sowndhararajan, Kandhasamy; Hong, Sunghyun; Lee, Jaehak; Park, Sun-Young; Kim, Songmun; Jhoo, Jin-Woo

    2014-01-01

    This study was designed to isolate and identify a potent inhibitory compound against nitric oxide (NO) production from the stem bark of Ulmus pumila L. Ethyl acetate fraction of hot water extract registered a higher level of total phenolics (756.93 mg GAE/g) and also showed strong DPPH (IC50 at 5.6 μg/mL) and ABTS (TEAC value 0.9703) radical scavenging activities than other fractions. Crude extract and its fractions significantly decreased nitrite accumulation in LPS-stimulated RAW 264.7 cells indicating that they potentially inhibited the NO production in a concentration dependent manner. Based on higher inhibitory activity, the ethyl acetate fraction was subjected to Sephadex LH-20 column chromatography and yielded seven fractions and all these fractions registered appreciable levels of inhibitory activity on NO production. The most effective fraction F1 was further purified and subjected to 1H, 13C-NMR and mass spectrometry analysis and the compound was identified as icariside E4. The results suggest that the U. pumila extract and the isolated compound icariside E4 effectively inhibited the NO production and may be useful in preventing inflammatory diseases mediated by excessive production of NO. PMID:25313277

  7. Ursolic acid isolated from guava leaves inhibits inflammatory mediators and reactive oxygen species in LPS-stimulated macrophages.

    PubMed

    Kim, Min-Hye; Kim, Jin Nam; Han, Sung Nim; Kim, Hye-Kyeong

    2015-06-01

    Psidium guajava (guava) leaves have been frequently used for the treatment of rheumatism, fever, arthritis and other inflammatory conditions. The purpose of this study was to identify major anti-inflammatory compounds from guava leaf extract. The methanol extract and its hexane-, dichloromethane-, ethylacetate-, n-butanol- and water-soluble phases derived from guava leaves were evaluated to determine their inhibitory activity on nitric oxide (NO) production by RAW 264.7 cells stimulated with lipopolysaccharide (LPS). The methanol extract decreased NO production in a dose-dependent manner without cytotoxicity at a concentration range of 0-100 μg/mL. The n-butanol soluble phase was the most potent among the five soluble phases. Four compounds were isolated by reversed-phase HPLC from the n-butanol soluble phase and identified to be avicularin, guaijaverin, leucocyanidin and ursolic acid by their NMR spectra. Among these compounds, ursolic acid inhibited LPS-induced NO production in a dose-dependent manner without cytotoxity at a concentration range of 1-10 µM, but the other three compounds had no effect. Ursolic acid also inhibited LPS-induced prostaglandin E2 production. A western blot analysis showed that ursolic acid decreased the LPS-stimulated inducible nitric oxide synthase and cyclooxygenase protein levels. In addition, ursolic acid suppressed the production of intracellular reactive oxygen species in LPS-stimulated RAW 264.7 cells, as measured by flow cytometry. Taken together, these results identified ursolic acid as a major anti-inflammatory compound in guava leaves. PMID:25753845

  8. Acute increase of α-synuclein inhibits synaptic vesicle recycling evoked during intense stimulation

    PubMed Central

    Busch, David J.; Oliphint, Paul A.; Walsh, Rylie B.; Banks, Susan M. L.; Woods, Wendy S.; George, Julia M.; Morgan, Jennifer R.

    2014-01-01

    Parkinson's disease is associated with multiplication of the α-synuclein gene and abnormal accumulation of the protein. In animal models, α-synuclein overexpression broadly impairs synaptic vesicle trafficking. However, the exact steps of the vesicle trafficking pathway affected by excess α-synuclein and the underlying molecular mechanisms remain unknown. Therefore we acutely increased synuclein levels at a vertebrate synapse and performed a detailed ultrastructural analysis of the effects on presynaptic membranes. At stimulated synapses (20 Hz), excess synuclein caused a loss of synaptic vesicles and an expansion of the plasma membrane, indicating an impairment of vesicle recycling. The N-terminal domain (NTD) of synuclein, which folds into an α-helix, was sufficient to reproduce these effects. In contrast, α-synuclein mutants with a disrupted N-terminal α-helix (T6K and A30P) had little effect under identical conditions. Further supporting this model, another α-synuclein mutant (A53T) with a properly folded NTD phenocopied the synaptic vesicle recycling defects observed with wild type. Interestingly, the vesicle recycling defects were not observed when the stimulation frequency was reduced (5 Hz). Thus excess α-synuclein impairs synaptic vesicle recycling evoked during intense stimulation via a mechanism that requires a properly folded N-terminal α-helix. PMID:25273557

  9. Inhibition of bombesin-stimulated acid secretion by immunoneutralization of gastrin in dogs.

    PubMed

    Kovacs, T O; Lloyd, K C; Wong, H; Walsh, J H

    1995-01-01

    Bombesin-like peptides stimulate gastrin release and gastric acid secretion. The increase in gastric acid output is thought to be secondary to gastrin release. A monoclonal antibody (MAb) directed specifically to gastrin (MAb 28.2) was used to study the role of circulating gastrin in the regulation of bombesin-stimulated acid secretion in dogs. Seven conscious, fasted dogs with gastric fistulas received intravenous bombesin infusions in fourfold increasing doses from 200 to 3,200 pmol.kg-1.h-1. Each dose was given for 45 min. On separate days, dogs were pretreated with an intravenous infusion of 7 mg of MAb 28.2 or vehicle (0.1% canine serum albumin). Samples of gastric effluent were collected by gravity drainage through the gastric fistula, and acid output was measured by titration of gastric effluent to pH 7.0, using 0.2 N NaOH. Plasma gastrin concentrations were determined by radioimmunoassay. Bombesin infusion produced dose-dependent increases in plasma gastrin concentrations and gastric acid output. Administration of gastrin MAb 28.2 abolished bombesin-stimulated gastric acid output. Immunoneutralization of circulating gastrin in vivo using a gastrin monoclonal antibody in dogs indicates that the acid stimulatory response to bombesin is mediated by gastrin. PMID:7840208

  10. Estrogens stimulate serotonin neurons to inhibit binge-like eating in mice.

    PubMed

    Cao, Xuehong; Xu, Pingwen; Oyola, Mario G; Xia, Yan; Yan, Xiaofeng; Saito, Kenji; Zou, Fang; Wang, Chunmei; Yang, Yongjie; Hinton, Antentor; Yan, Chunling; Ding, Hongfang; Zhu, Liangru; Yu, Likai; Yang, Bin; Feng, Yuxin; Clegg, Deborah J; Khan, Sohaib; DiMarchi, Richard; Mani, Shaila K; Tong, Qingchun; Xu, Yong

    2014-10-01

    Binge eating afflicts approximately 5% of US adults, though effective treatments are limited. Here, we showed that estrogen replacement substantially suppresses binge-like eating behavior in ovariectomized female mice. Estrogen-dependent inhibition of binge-like eating was blocked in female mice specifically lacking estrogen receptor-α (ERα) in serotonin (5-HT) neurons in the dorsal raphe nuclei (DRN). Administration of a recently developed glucagon-like peptide-1-estrogen (GLP-1-estrogen) conjugate designed to deliver estrogen to GLP1 receptor-enhanced regions effectively targeted bioactive estrogens to the DRN and substantially suppressed binge-like eating in ovariectomized female mice. Administration of GLP-1 alone reduced binge-like eating, but not to the same extent as the GLP-1-estrogen conjugate. Administration of ERα-selective agonist propylpyrazole triol (PPT) to murine DRN 5-HT neurons activated these neurons in an ERα-dependent manner. PPT also inhibited a small conductance Ca2+-activated K+ (SK) current; blockade of the SK current prevented PPT-induced activation of DRN 5-HT neurons. Furthermore, local inhibition of the SK current in the DRN markedly suppressed binge-like eating in female mice. Together, our data indicate that estrogens act upon ERα to inhibit the SK current in DRN 5-HT neurons, thereby activating these neurons to suppress binge-like eating behavior and suggest ERα and/or SK current in DRN 5-HT neurons as potential targets for anti-binge therapies. PMID:25157819

  11. Estrogens stimulate serotonin neurons to inhibit binge-like eating in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Binge eating afflicts approximately 5% of US adults, though effective treatments are limited. Here, we showed that estrogen replacement substantially suppresses binge-like eating behavior in ovariectomized female mice. Estrogen-dependent inhibition of binge-like eating was blocked in female mice spe...

  12. N-acetylaspartylglutamate (NAAG) inhibits intravenous cocaine self-administration and cocaine-enhanced brain-stimulation reward in rats.

    PubMed

    Xi, Zheng-Xiong; Kiyatkin, Michael; Li, Xia; Peng, Xiao-Qing; Wiggins, Armina; Spiller, Krista; Li, Jie; Gardner, Eliot L

    2010-01-01

    Pharmacological activation of group II metabotropic glutamate (mGlu2 and mGlu3) receptors inhibits reward-seeking behavior and/or rewarding efficacy induced by drugs (cocaine, nicotine) or natural rewards (food, sucrose). In the present study, we investigated whether elevation of brain N-acetylaspartylglutamate (NAAG), an endogenous group II mGlu receptor agonist, by the NAAG peptidase inhibitor 2-PMPA attenuates cocaine's rewarding effects, as assessed by intravenous cocaine self-administration and intracranial electrical brain-stimulation reward (BSR) in rats. Systemic administration of 2-PMPA (10, 30, 100 mg/kg, i.p.) or intranasal administration of NAAG (100, 300 microg/10 microl/nostril) significantly inhibited intravenous cocaine self-administration under progressive-ratio (PR), but not under fixed-ratio 2 (FR2), reinforcement conditions. In addition, 2-PMPA (1, 10, 30 mg/kg, i.p) or NAAG (50, 100 microg/10 microl/nostril) significantly inhibited cocaine-enhanced BSR, but not basal BSR. Pretreatment with LY341495 (1 mg/kg, i.p.), a selective mGlu2/3 receptor antagonist, prevented the inhibitory effects produced by 2-PMPA or NAAG in both the self-administration and BSR paradigms. In vivo microdialysis demonstrated that 2-PMPA (10, 30, 100 mg/kg) dose-dependently attenuated cocaine-enhanced extracellular dopamine (DA) in the nucleus accumbens (NAc). 2-PMPA alone inhibited basal NAc DA release, an effect that was prevented by LY341495. These findings suggest that systemic administration of 2-PMPA or intranasal administration of NAAG inhibits cocaine's rewarding efficacy and cocaine-enhanced NAc DA - likely by activation of presynaptic mGlu2/3 receptors in the NAc. These data suggest a potential utility for 2-PMPA or NAAG in the treatment of cocaine addiction. PMID:19559037

  13. Lack of strong anti-viral immune gene stimulation in Torque Teno Sus Virus1 infected macrophage cells.

    PubMed

    Singh, P; Ramamoorthy, S

    2016-08-01

    While recent findings suggest that swine TTVs (TTSuVs) can act as primary or co-infecting pathogens, very little is known about viral immunity. To determine whether TTSuVs downregulate key host immune responses to facilitate their own survival, a swine macrophage cell line, 3D4/31, was used to over-express recombinant TTSuV1 viral particles or the ORF3 protein. Immune gene expression profiles were assessed by a quantitative PCR panel consisting of 22 immune genes, in cell samples collected at 6, 12, 24 and 48h post-transfection. Despite the upregulation of IFN-β and TLR9, interferon stimulated innate genes and pro-inflammatory genes were not upregulated in virally infected cells. The adaptive immune genes, IL-4 and IL-13, were significantly downregulated at 6h post-transfection. The ORF3 protein did not appear do not have a major immuno-suppressive effect, nor did it stimulate anti-viral immunity. Data from this study warrants further investigation into the mechanisms of TTV related immuno-pathogenesis. PMID:27179346

  14. Breathing Stimulant Compounds Inhibit TASK-3 Potassium Channel Function Likely by Binding at a Common Site in the Channel Pore.

    PubMed

    Chokshi, Rikki H; Larsen, Aaron T; Bhayana, Brijesh; Cotten, Joseph F

    2015-11-01

    Compounds PKTHPP (1-{1-[6-(biphenyl-4-ylcarbonyl)-5,6,7,8-tetrahydropyrido[4,3-d]-pyrimidin-4-yl]piperidin-4-yl}propan-1-one), A1899 (2''-[(4-methoxybenzoylamino)methyl]biphenyl-2-carboxylic acid 2,4-difluorobenzylamide), and doxapram inhibit TASK-1 (KCNK3) and TASK-3 (KCNK9) tandem pore (K2P) potassium channel function and stimulate breathing. To better understand the molecular mechanism(s) of action of these drugs, we undertook studies to identify amino acid residues in the TASK-3 protein that mediate this inhibition. Guided by homology modeling and molecular docking, we hypothesized that PKTHPP and A1899 bind in the TASK-3 intracellular pore. To test our hypothesis, we mutated each residue in or near the predicted PKTHPP and A1899 binding site (residues 118-128 and 228-248), individually, to a negatively charged aspartate. We quantified each mutation's effect on TASK-3 potassium channel concentration response to PKTHPP. Studies were conducted on TASK-3 transiently expressed in Fischer rat thyroid epithelial monolayers; channel function was measured in an Ussing chamber. TASK-3 pore mutations at residues 122 (L122D, E, or K) and 236 (G236D) caused the IC50 of PKTHPP to increase more than 1000-fold. TASK-3 mutants L122D, G236D, L239D, and V242D were resistant to block by PKTHPP, A1899, and doxapram. Our data are consistent with a model in which breathing stimulant compounds PKTHPP, A1899, and doxapram inhibit TASK-3 function by binding at a common site within the channel intracellular pore region, although binding outside the channel pore cannot yet be excluded. PMID:26268529

  15. Noxious mechanical heterotopic stimulation induces inhibition of the spinal dorsal horn neuronal network: analysis of spinal somatosensory-evoked potentials.

    PubMed

    Meléndez-Gallardo, J; Eblen-Zajjur, A

    2016-09-01

    Most of the endogenous pain modulation (EPM) involves the spinal dorsal horn (SDH). EPM including diffuse noxious inhibitory controls have been extensively described in oligoneuronal electrophysiological recordings but less attention had been paid to responses of the SDH neuronal population to heterotopic noxious stimulation (HNS). Spinal somatosensory-evoked potentials (SEP) offer the possibility to evaluate the neuronal network behavior, reflecting the incoming afferent volleys along the entry root, SDH interneuron activities and the primary afferent depolarization. SEP from de lumbar cord dorsum were evaluated during mechanical heterotopic noxious stimuli. Sprague-Dawley rats (n = 12) were Laminectomized (T10-L3). The sural nerve of the left hind paw was electrically stimulated (5 mA, 0.5 ms, 0.05 Hz) to induce lumbar SEP. The HNS (mechanic clamp) was applied sequentially to the tail, right hind paw, right forepaw, muzzle and left forepaw during sural stimulation. N wave amplitude decreases (-16.6 %) compared to control conditions when HNS was applied to all areas of stimulation. This effect was more intense for muzzle stimulation (-23.5 %). N wave duration also decreased by -23.6 %. HNS did not change neither the amplitude nor the duration of the P wave but dramatically increases the dispersion of these two parameters. The results of the present study strongly suggest that a HNS applied to different parts of the body is able to reduce the integrated electrical response of the SDH, suggesting that not only wide dynamic range neurons but many others in the SDH are modulated by the EPM. PMID:27207681

  16. Estradiol and its membrane-impermeable conjugate estradiol-BSA inhibit tamoxifen-stimulated prolactin secretion in incubated rat pituitaries.

    PubMed

    Aguilar, R; Bellido, C; Garrido-Gracia, J C; Alonso, R; Sánchez-Criado, J E

    2006-04-01

    In the absence of estrogen (E), the selective E receptor modulator tamoxifen (TX) has two agonist effects in the rat pituitary: induction of progesterone receptor (PR)-dependent GnRH self-priming in the gonadotrope, and stimulation of prolactin (PRL) secretion in the lactotrope. TX-induced gonadotropin (GnRH) self-priming is absent when 10(-8) M estradiol-17beta (E2) is added to the incubation medium of pituitaries from TX-treated rats. The present experiments investigated whether PR-independent PRL release into the incubation medium of pituitaries from TX-treated ovariectomized (OVX) rats was affected by E2, and the effect of different ER ligands (ICI182780, TX, estradiol-17alpha, E2 -BSA) on TX-stimulated PRL secretion. Moreover, the effect of E2 on TRH-stimulated PRL secretion in pituitaries collected from estradiol benzoate- and TX-treated OVX rats was studied. It was found that: i) incubation with E2 supressed the PRL releasing effect of injected TX; ii) whereas coincubation with the pure anti-E type II ICI182780 antagonized the inhibitory effect of E2, coincubation with the anti-E type I TX did not; iii) estradiol-17alpha lacked inhibitory action, whereas a dose-dependent inhibitory effect of both E2 and E2 -BSA was noticed; and iv) TRH stimulatory effect on PRL release in pituitaries from TX-treated rats was blocked by addition of E2 to the medium. Taken together, these data argue in favor of the presence of specific membrane recognition sites for E in the lactotrope involved in steroid-specific E2 inhibition of TX-stimulated PRL secretion. PMID:16595727

  17. Nitric oxide production inhibition and mechanism of phenanthrene analogs in lipopolysaccharide-stimulated RAW264.7 macrophages.

    PubMed

    Chen, Lian-Qi; Shen, Xiao-Fei; Hu, Bo-Yang; Lin, Yuan; Igbe, Ighodaro; Zhang, Cheng-Gang; Zhang, Guo-Lin; Yuan, Xiao-Hong; Wang, Fei

    2016-05-15

    Natural phenanthrene derivatives are considered to be important resource for the anti-inflammatory therapeutics, but their structure-activity relationship and mechanisms are still unknown. In this study we evaluated 20 synthesized phenanthrene analogs in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Compounds 10, 11 and 17 were found to inhibit the production of nitric oxide (NO) with IC50 values of 37.26μM, 5.05μM and 20.31μM, respectively. Compound 11 decreased LPS-induced expression of inducible NO synthase (iNOS), inhibited phosphorylation of p38 mitogen-activated protein kinase (MAPK) and serine/threonine kinase Akt. It also suppressed the phosphorylation and degradation of inhibitory kappa B-α (IκBα). Data obtained suggest that compound 11 exerts anti-inflammatory effects by inhibiting p38 MAPK and nuclear factor κB (NF-κB) pathways, which warrants further investigation as a new anti-inflammatory pharmaceutical tool. PMID:27038497

  18. Naloxone reduces the amplitude of IPSPs evoked in lumbar motoneurons by reticular stimulation during carbachol-induced motor inhibition.

    PubMed

    Xi, M C; Liu, R H; Yamuy, J; Morales, F R; Chase, M H

    1999-02-20

    During active sleep or carbachol-induced motor inhibition, electrical stimulation of the medullary nucleus reticularis gigantocellularis (NRGc) evoked large amplitude, glycinergic inhibitory postsynaptic potentials (IPSPs) in cat motoneurons. The present study was directed to determine whether these IPSPs, that are specific to the state of active sleep, are modulated by opioid peptides. Accordingly, intracellular recordings were obtained from lumbar motoneurons of acute decerebrate cats during carbachol-induced motor inhibition while an opiate receptor antagonist, naloxone, was microiontophoretically released next to the recorded cells. Naloxone reversibly reduced by 26% the mean amplitude of NRGc-evoked IPSPs (1.9+/-0.2 mV (S.E.M.) vs. 1.4+/-0.2 mV; n=11, control and naloxone, respectively, p<0.05), but had no effect on the other waveform parameters of these IPSPs (e.g., latency-to-onset, latency-to-peak, duration, etc.). The mean resting membrane potential, input resistance and membrane time constant of motoneurons following naloxone ejection were not statistically different from those of the control. These data indicate that opioid peptides have a modulatory effect on NRGc-evoked IPSPs during carbachol-induced motor inhibition. We therefore suggest that endogenous opioid peptides may act as neuromodulators to regulate inhibitory glycinergic synaptic transmission at motoneurons during active sleep. PMID:10082872

  19. Matrix metalloproteinase inhibition influences aspects of photoperiod stimulated ovarian recrudescence in Siberian hamsters

    PubMed Central

    Shahed, Asha; Simmons, Jamie; Featherstone, Sydney L; Young, Kelly A.

    2015-01-01

    Blocking matrix metalloproteinase (MMP) activity in vivo with inhibitor GM6001 impedes photostimulated ovarian recrudescence in photoregressed Siberian hamsters. Since direct and indirect effects of MMPs influence a myriad of ovarian functions, we investigated the effect of in vivo MMP inhibition during recrudescence on ovarian mRNA expression of steroidogenic acute regulatory protein (StAR), 3β-hy-droxysteroid dehydrogenase (3β-HSD), Cyp19a1 aromatase, epidermal growth factor receptor (EGFR), amphiregulin (Areg), estrogen receptors (Esr1 and Esr2), tissue inhibitors of MMPs (TIMP-1,-2,-3), proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor A (VEGFA), its receptor VEGFR-2, and angiopoietin-2 (Ang-2). Female Siberian hamsters were randomly assigned to one of four photoperiod groups: stimulatory long (LD) or inhibitory short (SD) photoperiods, or transferred from SD to LD for 2 weeks (post-transfer, PT). Half of the PT hamsters were injected (ip) daily with GM6001 (PTG). SD exposure reduced ovarian StAR, 3β-HSD, Cyp19a1, Esr1, Esr2, TIMPs 2–3, PCNA, VEGFR-2 and Ang-2 mRNA expression (p < 0.05), and 2 weeks of photostimulation restored mRNA expression of 3β-HSD and PCNA and increased Areg and VEGFA mRNA expression in the PT group. GM6001 treatment during photostimulation (PTG) increased TIMP-1, -2 and -3 and PCNA mRNA, but inhibited Areg mRNA expression compared to PT. Neither photoperiod nor GM6001 altered EGFR expression. Results of this study suggest that in vivo inhibition of MMP activity by GM6001 may impede ovarian recrudescence, particularly follicular growth, in two ways: (1) directly by partially inhibiting the release of EGFR ligands like Areg, thereby potentially affecting EGFR activation and its downstream pathway, and (2) indirectly by its effect on TIMPs which themselves can affect proliferation, angiogenesis and follicular growth. PMID:25910436

  20. Tyrosol and its analogues inhibit alpha-melanocyte-stimulating hormone induced melanogenesis.

    PubMed

    Wen, Kuo-Ching; Chang, Chih-Shiang; Chien, Yin-Chih; Wang, Hsiao-Wen; Wu, Wan-Chen; Wu, Chin-Sheng; Chiang, Hsiu-Mei

    2013-01-01

    Melanin is responsible for skin color and plays a major role in defending against harmful external factors such as ultraviolet (UV) irradiation. Tyrosinase is responsible for the critical steps of melanogenesis, including the rate-limiting step of tyrosine hydroxylation. The mechanisms of action of skin hypopigmenting agents are thought to be based on the ability of a given agent to inhibit the activity of tyrosinase and, hence, down regulate melanin synthesis. Tyrosol and its glycoside, salidroside, are active components of Rhodiola rosea, and in our preliminary study we found that Rhodiola rosea extract inhibited melanogenesis. In this study, we examined the effects of tyrosol and its analogues on melanin synthesis. We found that treatment of B16F0 cells to tyrosol (1), 4-hydroxyphenylacetic acid (5), 3-hydroxyphenylacetic acid (6), 2-hydroxyphenylacetic acid (7), or salidroside (11) resulted in a reduction in melanin content and inhibition of tyrosinase activity as well as its expression. Tyrosol (1), 4-hydroxyphenylacetic acid (5) and 2-hydroxyphenylacetic acid (7) suppressed MC1R expression. Tyrosol (1), 4-hydroxyphenylacetic acid (5), 3-hydroxyphenylacetic acid (6), and 2-hydroxyphenylacetic acid (7) inhibited α-MSH induced TRP-1 expression, but salidroside (11) did not. All the compounds did not affect MITF and TRP-2 expression. Furthermore, we found that the cell viability of tyrosol (1), 4-hydroxyphenylacetic acid (5), 3-hydroxyphenylacetic acid (6), and 2-hydroxyphenylacetic acid (7) at concentrations below 4 mM and salidroside (11) at concentrations below 0.5 mM were higher than 90%. The compounds exhibited metal-coordinating interactions with copper ion in molecular docking with tyrosinase. Our results suggest that tyrosol, 4-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 2-hydroxyphenylacetic acid, and salidroside are potential hypopigmenting agents. PMID:24287915

  1. Interleukin-1β inhibits synthesis of 5-lipooxygenase in lipopolysaccharide-stimulated equine whole blood.

    PubMed

    Mangal, Dipti; Uboh, Cornelius E; Jiang, Zibin; Soma, Lawrence R

    2014-01-01

    Interleukin-1β (IL-1β) is a pro-inflammatory cytokine. It induces the synthesis of prostaglandin E2 (PGE2) catalyzed by cyclooxygenase (COX) and microsomal prostaglandin E synthase (m-PGES). Besides its pro-inflammatory properties, PGE2 also exhibits anti-inflammatory properties by inhibiting synthesis of 5-lipooxygenase (5-LO) products which are in themselves, pro-inflammatory mediators. Thus, inhibition of 5-LO products is beneficial in regulating immune-responses and pro-inflammatory processes. To investigate the hypothesis that IL-1β is responsible for the increase in the synthesis of PGE2 and in the reduction of 5-LO products, equine whole blood (EWB) was treated with lipopolysaccharide (LPS). In vitro treatment of EWB with LPS resulted in increased expression of IL-1β while expression of 5-LO was suppressed. Quantification of eicosanoids using liquid-chromatography-mass spectrometry/multiple reaction monitoring (LC-MS/MRM) showed increased concentrations of prostaglandins and decreased 5-LO products in LPS-treated EWB. Pretreatment of EWB with IL-1β followed by calcium ionophore A23187 (CI) reduced synthesis of 5-LO products. However, pretreatment of EWB with COX-2 inhibitor (NS-398) or m-PGES-1 inhibitor (CAY 10526) and IL-1β followed with CI resulted in a significant (p<0.0001) increase in 5-LO products. Pretreatment of EWB with phospholipase C inhibitor (U73122) followed with LPS reduced PGE2 production but increased 5-LO products. The result of this study indicated that increased PGE2 production led to reduction in 5-LO products in LPS-treated EWB via IL-1β. However, other pathways, cytokines and mediators may be involved in inhibiting 5-LO products but the present study did not include those other potential pathways. Inhibition of 5-LO products by PGE2 in EWB may regulate the initiation and pathogenesis of inflammatory responses in the horse. PMID:24530239

  2. Estrogens stimulate serotonin neurons to inhibit binge-like eating in mice

    PubMed Central

    Cao, Xuehong; Xu, Pingwen; Oyola, Mario G.; Xia, Yan; Yan, Xiaofeng; Saito, Kenji; Zou, Fang; Wang, Chunmei; Yang, Yongjie; Hinton, Antentor; Yan, Chunling; Ding, Hongfang; Zhu, Liangru; Yu, Likai; Yang, Bin; Feng, Yuxin; Clegg, Deborah J.; Khan, Sohaib; DiMarchi, Richard; Mani, Shaila K.; Tong, Qingchun; Xu, Yong

    2014-01-01

    Binge eating afflicts approximately 5% of US adults, though effective treatments are limited. Here, we showed that estrogen replacement substantially suppresses binge-like eating behavior in ovariectomized female mice. Estrogen-dependent inhibition of binge-like eating was blocked in female mice specifically lacking estrogen receptor-α (ERα) in serotonin (5-HT) neurons in the dorsal raphe nuclei (DRN). Administration of a recently developed glucagon-like peptide-1–estrogen (GLP-1–estrogen) conjugate designed to deliver estrogen to GLP1 receptor–enhanced regions effectively targeted bioactive estrogens to the DRN and substantially suppressed binge-like eating in ovariectomized female mice. Administration of GLP-1 alone reduced binge-like eating, but not to the same extent as the GLP-1–estrogen conjugate. Administration of ERα-selective agonist propylpyrazole triol (PPT) to murine DRN 5-HT neurons activated these neurons in an ERα-dependent manner. PPT also inhibited a small conductance Ca2+-activated K+ (SK) current; blockade of the SK current prevented PPT-induced activation of DRN 5-HT neurons. Furthermore, local inhibition of the SK current in the DRN markedly suppressed binge-like eating in female mice. Together, our data indicate that estrogens act upon ERα to inhibit the SK current in DRN 5-HT neurons, thereby activating these neurons to suppress binge-like eating behavior and suggest ERα and/or SK current in DRN 5-HT neurons as potential targets for anti-binge therapies. PMID:25157819

  3. Tyrosol and Its Analogues Inhibit Alpha-Melanocyte-Stimulating Hormone Induced Melanogenesis

    PubMed Central

    Wen, Kuo-Ching; Chang, Chih-Shiang; Chien, Yin-Chih; Wang, Hsiao-Wen; Wu, Wan-Chen; Wu, Chin-Sheng; Chiang, Hsiu-Mei

    2013-01-01

    Melanin is responsible for skin color and plays a major role in defending against harmful external factors such as ultraviolet (UV) irradiation. Tyrosinase is responsible for the critical steps of melanogenesis, including the rate-limiting step of tyrosine hydroxylation. The mechanisms of action of skin hypopigmenting agents are thought to be based on the ability of a given agent to inhibit the activity of tyrosinase and, hence, down regulate melanin synthesis. Tyrosol and its glycoside, salidroside, are active components of Rhodiola rosea, and in our preliminary study we found that Rhodiola rosea extract inhibited melanogenesis. In this study, we examined the effects of tyrosol and its analogues on melanin synthesis. We found that treatment of B16F0 cells to tyrosol (1), 4-hydroxyphenylacetic acid (5), 3-hydroxyphenylacetic acid (6), 2-hydroxyphenylacetic acid (7), or salidroside (11) resulted in a reduction in melanin content and inhibition of tyrosinase activity as well as its expression. Tyrosol (1), 4-hydroxyphenylacetic acid (5) and 2-hydroxyphenylacetic acid (7) suppressed MC1R expression. Tyrosol (1), 4-hydroxyphenylacetic acid (5), 3-hydroxyphenylacetic acid (6), and 2-hydroxyphenylacetic acid (7) inhibited α-MSH induced TRP-1 expression, but salidroside (11) did not. All the compounds did not affect MITF and TRP-2 expression. Furthermore, we found that the cell viability of tyrosol (1), 4-hydroxyphenylacetic acid (5), 3-hydroxyphenylacetic acid (6), and 2-hydroxyphenylacetic acid (7) at concentrations below 4 mM and salidroside (11) at concentrations below 0.5 mM were higher than 90%. The compounds exhibited metal-coordinating interactions with copper ion in molecular docking with tyrosinase. Our results suggest that tyrosol, 4-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 2-hydroxyphenylacetic acid, and salidroside are potential hypopigmenting agents. PMID:24287915

  4. Orexin B inhibits proliferation and stimulates specialized function of cultured rat calvarial osteoblast-like cells.

    PubMed

    Ziolkowska, Agnieszka; Rucinski, Marcin; Tyczewska, Marianna; Malendowicz, Ludwik K

    2008-12-01

    Orexin-A (OXA) and orexin-B (OXB) are polypeptides derived from the same 130 amino acid long precursor (prepro-orexin) that bind and activate two closely related orphan G protein-coupled receptors OX1-R and OX2-R. These hypothalamic neuropeptides stimulate food intake and energy expenditure and play a significant role in sleep-wakefulness regulation. Present studies aimed to investigate the effects of orexins on proliferative activity and osteocalcin secretion by cultured rat calvarial osteoblast-like (ROB) cells. Conventional RT-PCR methods detected expression of the OX1-R gene in freshly isolated ROB cells and cells cultured for 7, 14 and 21 days. In contrast, at all time points tested, expression of prepro-OX or OX2-R genes was not demonstrated. QPCR revealed the highest expression of OX1-R gene in freshly isolated bone cells and a notably lower one in cultured ROB cells. Exposure of cultured cells to both OXA and OXB stimulated expression of the OX1-R gene. However, this effect was seen at the lowest tested concentration (1x10(-10) M). Exposure of cultured ROB cells to OXA for 48 h did not change osteocalcin concentrations in media analyzed at days 7, 14 and 21 of culture. On the contrary, OXB notably stimulated osteocalcin concentrations in media taken at days 14 and 21 of culture. In contrast, OXA exerted a notable inhibitory effect on the proliferative activity of ROB cells at day 7 of culture, while OXB exerted a similar effect at day 14. Thus, the obtained results suggest that: (i)(ROB) cells are provided with functional OX1-R gene; (ii) in ROB cells expression of this gene seems to be up-regulated by low concentrations of both OXA and OXB; (iii) OXB exerts inhibitory effects on proliferative activity and stimulating effects on osteocalcin secretion by cultured ROB cells; (iv) rat calvarial osteoblasts provided with OX receptor may be a target for circulating orexins. Thus, orexins may be included in the expanding group of neuropeptides involved in the

  5. Inhibition of intracellular proteolysis in muscle cultures by multiplication-stimulating activity

    NASA Technical Reports Server (NTRS)

    Janeczko, Richard A.; Etlinger, Joseph D.

    1984-01-01

    The effects of the insulin-like growth factor, multiplication-stimulating activity (MSA), on chick myotube cultures are studied. The results indicate that MSA is an effective anabolic agent regulating protein metabolism and amino acid uptake, but not sugar transport. Similar size effects on protein metabolism and amino acid uptake in serum-free media were observed in parallel studies with insulin, although insulin levels well in excess of the normal physiological range are required to produce significant effects. It is suggested that there is a generally low insulin sensitivity in cultured chick myotubes relative to adult tissues.

  6. Breathing Inhibited When Seizures Spread to the Amygdala and upon Amygdala Stimulation

    PubMed Central

    Gehlbach, Brian K.; Kreple, Collin J.; Kawasaki, Hiroto; Oya, Hiroyuki; Buzza, Colin; Granner, Mark A.; Welsh, Michael J.; Howard, Matthew A.; Wemmie, John A.; Richerson, George B.

    2015-01-01

    Sudden unexpected death in epilepsy (SUDEP) is increasingly recognized as a common and devastating problem. Because impaired breathing is thought to play a critical role in these deaths, we sought to identify forebrain sites underlying seizure-evoked hypoventilation in humans. We took advantage of an extraordinary clinical opportunity to study a research participant with medically intractable epilepsy who had extensive bilateral frontotemporal electrode coverage while breathing was monitored during seizures recorded by intracranial electrodes and mapped by high-resolution brain imaging. We found that central apnea and O2 desaturation occurred when seizures spread to the amygdala. In the same patient, localized electrical stimulation of the amygdala reproduced the apnea and O2 desaturation. Similar effects of amygdala stimulation were observed in two additional subjects, including one without a seizure disorder. The participants were completely unaware of the apnea evoked by stimulation and expressed no dyspnea, despite being awake and vigilant. In contrast, voluntary breath holding of similar duration caused severe dyspnea. These findings suggest a functional connection between the amygdala and medullary respiratory network in humans. Moreover, they suggest that seizure spread to the amygdala may cause loss of spontaneous breathing of which patients are unaware, and thus has potential to contribute to SUDEP. SIGNIFICANCE STATEMENT Sudden unexpected death in epilepsy (SUDEP) is the most common cause of death in patients with chronic refractory epilepsy. Impaired breathing during and after seizures is common and suspected to play a role in SUDEP. Understanding the cause of this peri-ictal hypoventilation may lead to preventative strategies. In epilepsy patients, we found that seizure invasion of the amygdala co-occurred with apnea and oxygen desaturation, and electrical stimulation of the amygdala reproduced these respiratory findings. Strikingly, the subjects were

  7. CTRP6 inhibits fibrogenesis in TGF-β1-stimulated human dermal fibroblasts.

    PubMed

    Fan, Rong-Hui; Zhu, Xiu-Mei; Sun, Yao-Wen; Peng, Hui-Zi; Wu, Hang-Li; Gao, Wen-Jie

    2016-07-01

    Skin fibrosis is characterized by excessive proliferation of fibroblasts and overproduction of extracellular matrix (ECM). C1q/tumor necrosis factor-related protein 6 (CTRP6), a member of CTRPs, has been involved in the development of cardiac fibrosis. However, the function and detailed regulatory mechanism of CTRP6 in skin fibrosis remain unclear. The aim of this study was to investigate the effect of CTRP6 on the activation of human dermal fibroblasts. Our results showed that CTRP6 was lowly expressed in scar tissues and transforming growth factor-β1 (TGF-β1)-treated dermal fibroblasts. CTRP6 overexpression significantly inhibited the proliferation of dermal fibroblasts, as well as suppressed the expression of ECM in TGF-β1-treated dermal fibroblasts. Furthermore, CTRP6 overexpression markedly inhibited TGF-β1-induced phosphorylation of Smad3 in dermal fibroblasts. In conclusion, the data reported here demonstrate that CTRP6 is able to inhibit the proliferation and ECM expression in human dermal fibroblasts through suppressing the TGF-β1/Smad3 signaling pathway. These findings suggest that CTRP6 may be a potential therapeutic target for the prevention of skin fibrosis. PMID:27155158

  8. STAT3 paradoxically stimulates β-catenin expression but inhibits β-catenin function

    PubMed Central

    Ibrahem, Salih; Al-Ghamdi, Saleh; Baloch, Kanwal; Muhammad, Belal; Fadhil, Wakkas; Jackson, Darryl; Nateri, Abdolrahman S; Ilyas, Mohammad

    2014-01-01

    Wnt signalling and the signal transducer and activator of transcription 3 (STAT3) are oncogenic signalling pathways which are deregulated in colorectal cancer (CRC). Here we investigated the interaction of these two pathways. Firstly, we investigated biochemical interaction by inhibiting STAT3 and β-catenin (through gene knock-down and dominant-negative TCF4 expression) in nine CRC cell lines. β-catenin inhibition did not affect STAT3 levels, whereas STAT3 knock-down resulted in reduced β-catenin mRNA and protein levels. The reduction in β-catenin protein was not prevented by proteasome inhibition, and IL6-induced STAT3 activation resulted in increased β-catenin mRNA. This suggests that STAT3 positively regulates β-catenin (at a transcriptional level) and evaluation of 44 CRCs by immunostaining supported this by showing an association between nuclear STAT3 expression and nuclear β-catenin (P = 0.022). We tested the functional interaction between STAT3 and Wnt signalling by knocking down STAT3 and β-catenin individually and in combination. Knock-down of β-catenin and STAT3 individually inhibited cell proliferation (P < 0. 001 for each) through G1 arrest. However, simultaneous knock-down of STAT3 and β-catenin had a significantly weaker effect than knock-down of β-catenin alone (P < 0.01). Knock-down of STAT3 and β-catenin, individually and together, inhibited cell motility (P < 0.001) without evidence of interaction. We conclude that STAT3 regulates β-catenin but β-catenin does not regulate STAT3. The STAT3/β-catenin interaction is complex but may reduce the proliferative activity of β-catenin possibly by taking β-catenin protein beyond the optimal level. This may indicate biological differences in tumours where both STAT3 and β-catenin are activated compared to those where only one is activated. PMID:25348333

  9. Myostatin inhibits proliferation and insulin-stimulated glucose uptake in mouse liver cells.

    PubMed

    Watts, Rani; Ghozlan, Mostafa; Hughey, Curtis C; Johnsen, Virginia L; Shearer, Jane; Hittel, Dustin S

    2014-06-01

    Although myostatin functions primarily as a negative regulator of skeletal muscle growth and development, accumulating biological and epidemiological evidence indicates an important contributing role in liver disease. In this study, we demonstrate that myostatin suppresses the proliferation of mouse Hepa-1c1c7 murine-derived liver cells (50%; p < 0.001) in part by reducing the expression of the cyclins and cyclin-dependent kinases that elicit G1-S phase transition of the cell cycle (p < 0.001). Furthermore, real-time PCR-based quantification of the long noncoding RNA metastasis associated lung adenocarcinoma transcript 1 (Malat1), recently identified as a myostatin-responsive transcript in skeletal muscle, revealed a significant downregulation (25% and 50%, respectively; p < 0.05) in the livers of myostatin-treated mice and liver cells. The importance of Malat1 in liver cell proliferation was confirmed via arrested liver cell proliferation (p < 0.05) in response to partial Malat1 siRNA-mediated knockdown. Myostatin also significantly blunted insulin-stimulated glucose uptake and Akt phosphorylation in liver cells while increasing the phosphorylation of myristoylated alanine-rich C-kinase substrate (MARCKS), a protein that is essential for cancer cell proliferation and insulin-stimulated glucose transport. Together, these findings reveal a plausible mechanism by which circulating myostatin contributes to the diminished regenerative capacity of the liver and diseases characterized by liver insulin resistance. PMID:24882465

  10. Predicting Modulation in Corticomotor Excitability and in Transcallosal Inhibition in Response to Anodal Transcranial Direct Current Stimulation

    PubMed Central

    Davidson, Travis W.; Bolic, Miodrag; Tremblay, François

    2016-01-01

    Introduction: Responses to neuromodulatory protocols based either on transcranial direct current stimulation (tDCS) or transcranial magnetic stimulation (TMS) are known to be highly variable between individuals. In this study, we examined whether variability of responses to anodal tDCS (a-tDCS) could be predicted from individual differences in the ability to recruit early or late indirect waves (I-waves), as reflected in latency differences of motor evoked potentials (MEPs) evoked by TMS of different coil orientation. Methods: Participants (n = 20) first underwent TMS to measure latency of MEPs elicited at different coil orientations (i.e., PA, posterior-anterior; AP, anterior-posterior; LM, latero-medial). Then, participants underwent a-tDCS (20 min @ 2 mA) targeting the primary motor cortex of the contralateral preferred hand (right, n = 18). Individual responses to a-tDCS were determined by monitoring changes in MEP amplitude at rest and in the duration of the contralateral silent period (cSP) and ipsilateral silent period (iSP) during contraction; the latter providing an index of the latency and duration of transcallosal inhibition (LTI and DTI). Results: Consistent with previous reports, individual responses to a-tDCS were highly variable when expressed in terms of changes in MEP amplitude or in cSP duration with ~50% of the participants showing either little or no modulation. In contrast, individual variations in measures of transcallosal inhibition were less variable, allowing detection of significant after-effects. The reduced LTI and prolonged DTI observed post-tDCS were indicative of an enhanced excitability of the transcallosal pathway in the stimulated hemisphere. In terms of predictions, AP-LM latency differences proved to be good predictors of responses to a-tDCS when considering MEP modulation. Conclusion: The present results corroborate the predictive value of latency differences derived from TMS to determine who is likely to express

  11. Attenuation of functional hyperemia to visual stimulation in mild Alzheimer's disease and its sensitivity to cholinesterase inhibition.

    PubMed

    Janik, Rafal; Thomason, Lynsie A M; Chaudhary, Simone; Dorr, Adrienne; Scouten, Amy; Schwindt, Graeme; Masellis, Mario; Stanisz, Greg J; Black, Sandra E; Stefanovic, Bojana

    2016-05-01

    Despite the growing recognition of the significance of cerebrovascular impairment in the etiology and progression of Alzheimer's disease (AD), the early stage brain vascular dysfunction and its sensitivity to pharmacological interventions is still not fully characterized. Due to the early and aggressive treatment of probable AD with cholinesterase inhibitors (ChEI), which in and of themselves have direct effects on brain vasculature, the vast majority of hemodynamic measurements in early AD subjects reported hitherto have consequently been made only after the start of treatment, complicating the disentanglement of disease- vs. treatment-related effects on the cerebral vasculature. To address this gap, we used pseudo continuous arterial spin labeling MRI to measure resting perfusion and visual stimulation elicited changes in cerebral blood flow (CBF) and blood oxygenation dependent (BOLD) fMRI signal in a cohort of mild AD patients immediately prior to, 6months post, and 12months post commencement of open label cholinesterase inhibitor treatment. Although patients exhibited no gray matter atrophy prior to treatment and their resting perfusion was not distinguishable from that in age, education and gender-matched controls, the patients' visual stimulation-elicited changes in BOLD fMRI and blood flow were decreased by 10±4% (BOLD) and 23±2% (CBF), relative to those in controls. Induction of cholinesterase inhibition treatment was associated with a further, 7±2% reduction in patients' CBF response to visual stimulation, but it stabilized, at this new lower level, over the follow-up period. Likewise, MMSE scores remained stable during the treatment; furthermore, higher MMSE scores were associated with higher perfusion responses to visual stimulation. This study represents the initial step in disentangling the effects of AD pathology from those of the first line treatment with cholinesterase inhibitors on cerebral hemodynamics and supports the use of arterial spin

  12. DCP-LA stimulates AMPA receptor exocytosis through CaMKII activation due to PP-1 inhibition.

    PubMed

    Kanno, Takeshi; Yaguchi, Takahiro; Nagata, Tetsu; Tanaka, Akito; Nishizaki, Tomoyuki

    2009-10-01

    The linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) activated Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) by inhibiting protein phosphatase-1 (PP-1). DCP-LA induced a transient huge facilitation of synaptic transmission monitored from the CA1 region of rat hippocampal slices, which was largely inhibited by the CaMKII inhibitor KN-93. DCP-LA potentiated kainate-evoked whole-cell membrane currents for Xenopus oocytes expressing alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors composed of the GluR1, GluR3, GluR1/GluR2, GluR1/GluR3, and GluR1/GluR2/GluR3 subunits, and the potentiation was significantly inhibited by KN-93. A similar potentiation was still found with mutant GluR1 (S831A) receptor lacking CaMKII phosphorylation site. The GluR1 and GluR2 subunits formed AMPA receptors in the rat hippocampus, and DCP-LA increased expression of both the subunits on the plasma membrane. The DCP-LA action was blocked by KN-93 and the exocytosis inhibitor botulinum toxin type A, but not by the endocytosis inhibitor phenylarsine oxide. DCP-LA, thus, appears to activate CaMKII through PP-1 inhibition, that stimulates AMPA receptor exocytosis to increase expression of the receptors on the plasma membrane, responsible for potentiate AMPA receptor responses and facilitation of hippocampal synaptic transmission. PMID:19492412

  13. Nicotine inhibits collagen synthesis and alkaline phosphatase activity, but stimulates DNA synthesis in osteoblast-like cells

    SciTech Connect

    Ramp, W.K.; Lenz, L.G.; Galvin, R.J. )

    1991-05-01

    Use of smokeless tobacco is associated with various oral lesions including periodontal damage and alveolar bone loss. This study was performed to test the effects of nicotine on bone-forming cells at concentrations that occur in the saliva of smokeless tobacco users. Confluent cultures of osteoblast-like cells isolated from chick embryo calvariae were incubated for 2 days with nicotine added to the culture medium (25-600 micrograms/ml). Nicotine inhibited alkaline phosphatase in the cell layer and released to the medium, whereas glycolysis (as indexed by lactate production) was unaffected or slightly elevated. The effects on medium and cell layer alkaline phosphatase were concentration dependent with maximal inhibition occurring at 600 micrograms nicotine/ml. Nicotine essentially did not affect the noncollagenous protein content of the cell layer, but did inhibit collagen synthesis (hydroxylation of ({sup 3}H)proline and collagenase-digestible protein) at 100, 300, and 600 micrograms/ml. Release of ({sup 3}H)hydroxyproline to the medium was also decreased in a dose-dependent manner, as was the collagenase-digestible protein for both the medium and cell layer. In contrast, DNA synthesis (incorporation of ({sup 3}H)thymidine) was more than doubled by the alkaloid, whereas total DNA content was slightly inhibited at 600 micrograms/ml, suggesting stimulated cell turnover. Morphologic changes occurred in nicotine-treated cells including rounding up, detachment, and the occurrence of numerous large vacuoles. These results suggest that steps to reduce the salivary concentration of nicotine in smokeless tobacco users might diminish damaging effects of this product on alveolar bone.

  14. Inhibition of autophagy stimulate molecular iodine-induced apoptosis in hormone independent breast tumors

    SciTech Connect

    Singh, Preeti; Godbole, Madan; Rao, Geeta; Annarao, Sanjay; Mitra, Kalyan; Roy, Raja; Ingle, Arvind; Agarwal, Gaurav; Tiwari, Swasti

    2011-11-11

    Highlights: Black-Right-Pointing-Pointer Molecular iodine (I{sub 2}) causes non-apoptotic cell death in MDA-MB231 breast tumor cells. Black-Right-Pointing-Pointer Autophagy is activated as a survival mechanism in response to I{sub 2} in MDA-MB231. Black-Right-Pointing-Pointer Autophagy inhibition sensitizes tumor cells to I{sub 2}-induced apoptotic cell death. Black-Right-Pointing-Pointer Autophagy inhibitor potentiates apoptosis and tumor regressive effects of I{sub 2} in mice. -- Abstract: Estrogen receptor negative (ER{sup -ve}) and p53 mutant breast tumors are highly aggressive and have fewer treatment options. Previously, we showed that molecular Iodine (I{sub 2}) induces apoptosis in hormone responsive MCF-7 breast cancer cells, and non-apoptotic cell death in ER{sup -ve}-p53 mutant MDA-MB231 cells (Shrivastava, 2006). Here we show that I{sub 2} (3 {mu}M) treatment enhanced the features of autophagy in MDA-MB231 cells. Since autophagy is a cell survival response to most anti-cancer therapies, we used both in vitro and in vivo systems to determine whether ER{sup -ve} mammary tumors could be sensitized to I{sub 2}-induced apoptosis by inhibiting autophagy. Autophagy inhibition with chloroquine (CQ) and inhibitors for PI3K (3MA, LY294002) and H+/ATPase (baflomycin) resulted in enhanced cell death in I{sub 2} treated MDA-MB231 cells. Further, CQ (20 {mu}M) in combination with I{sub 2}, showed apoptotic features such as increased sub-G1 fraction ({approx}5-fold), expression of cleaved caspase-9 and -3 compared to I{sub 2} treatment alone. Flowcytometry of I{sub 2} and CQ co-treated cells revealed increase in mitochondrial membrane permeability (p < 0.01) and translocation of cathepsin D activity to cytosol relative to I{sub 2} treatment. For in vivo studies ICRC mice were transplanted subcutaneously with MMTV-induced mammary tumors. A significant reduction in tumor volumes, as measured by MRI, was found in I{sub 2} and CQ co-treated mice relative to I{sub 2} or

  15. Molecular mechanisms of T cell co-stimulation and co-inhibition

    PubMed Central

    Chen, Lieping; Flies, Dallas B.

    2013-01-01

    Co-stimulatory and co-inhibitory receptors have a pivotal role in T cell biology, as they determine the functional outcome of T cell receptor (TCR) signalling. The classic definition of T cell co-stimulation continues to evolve through the identification of new co-stimulatory and co-inhibitory receptors, the biochemical characterization of their downstream signalling events and the delineation of their immunological functions. Notably, it has been recently appreciated that co-stimulatory and co-inhibitory receptors display great diversity in expression, structure and function, and that their functions are largely context dependent. Here, we focus on some of these emerging concepts and review the mechanisms through which T cell activation, differentiation and function is controlled by co-stimulatory and co-inhibitory receptors. PMID:23470321

  16. Gastric acid secretion in the dog: a mechanism-based pharmacodynamic model for histamine stimulation and irreversible inhibition by omeprazole.

    PubMed

    Abelö, Angela; Holstein, Björn; Eriksson, Ulf G; Gabrielsson, Johan; Karlsson, Mats O

    2002-08-01

    A mechanism-based pharmacodynamic model was used to describe the inhibitory effect by omeprazole on gastric acid secretion measured after histamine stimulation in the dog. The model identifies parameters that are related to the physiological system, the histamine stimulation, and the irreversible effect of omeprazole on the H+, K(+)-ATPase enzyme. Four different experiments with omeprazole (Exps. 1-4) and two placebo experiments were performed in each of the four Heidenhain pouch dogs used. For placebo and experiments 1-3, saline or omeprazole 0.81 mumol/kg was infused during 3 hr with measurements of histamine-stimulated gastric acid secretion in two periods of 3.5-6.5 hr, one period starting just before the omeprazole infusion and a second later period up to 29 hr post infusion. In experiment 4, 0.18 mumol/kg of omeprazole was infused for 22.5 min and gastric juice was collected for 5 hr post infusion. The response data was well described by the model. Similar parameter estimates were obtained by three different analysis methods; naïve pooling, two-stage method and nonlinear mixed effects modeling. The elimination rate constant for the H+, K(+)-ATPase enzyme, kout, was estimated to be 0.040 hr-1, corresponding to a half-life of about 17 hr. This rate constant determines the duration of omeprazole inhibition after long-term exposure. For short-term omeprazole exposure the duration is determined by the rate constant for transfer of enzymes from active to resting state, estimated to be 1.88 hr-1. The second-order rate constant for histamine stimulation was estimated to be 0.064 hr-1 per histamine concentration unit and the maximum acid secretion was estimated to be 5.0 mmol H+/30 min. The second-order rate constant for the irreversible binding of omeprazole to H+, K(+)-ATPase, kome, was estimated to be 2.39 L/mumol.hr. By modeling the histamine-induced baseline response simultaneously with active treatment, predictions of the response are possible not only

  17. Small Molecule Inhibition of Ligand-Stimulated RAGE-DIAPH1 Signal Transduction

    PubMed Central

    Manigrasso, Michaele B.; Pan, Jinhong; Rai, Vivek; Zhang, Jinghua; Reverdatto, Sergey; Quadri, Nosirudeen; DeVita, Robert J.; Ramasamy, Ravichandran; Shekhtman, Alexander; Schmidt, Ann Marie

    2016-01-01

    The receptor for advanced glycation endproducts (RAGE) binds diverse ligands linked to chronic inflammation and disease. NMR spectroscopy and x-ray crystallization studies of the extracellular domains of RAGE indicate that RAGE ligands bind by distinct charge- and hydrophobicity-dependent mechanisms. The cytoplasmic tail (ct) of RAGE is essential for RAGE ligand-mediated signal transduction and consequent modulation of gene expression and cellular properties. RAGE signaling requires interaction of ctRAGE with the intracellular effector, mammalian diaphanous 1 or DIAPH1. We screened a library of 58,000 small molecules and identified 13 small molecule competitive inhibitors of ctRAGE interaction with DIAPH1. These compounds, which exhibit in vitro and in vivo inhibition of RAGE-dependent molecular processes, present attractive molecular scaffolds for the development of therapeutics against RAGE-mediated diseases, such as those linked to diabetic complications, Alzheimer’s disease, and chronic inflammation, and provide support for the feasibility of inhibition of protein-protein interaction (PPI). PMID:26936329

  18. Dopamine transporter occupancy by RTI-55, inhibition of dopamine transport and stimulation of locomotor activity

    SciTech Connect

    Gatley, S.J.; Gifford, A.N.; Volkow, N.D.

    1997-05-01

    Cocaine analogs such as RTI-55 (or {beta}CIT) with a higher affinity for the DAT are potentially useful as therapeutic drugs in cocaine abuse as well as for radiopharmaceutical use. Previously we showed that in mice RTI-55 (2 mg/Kg, i/p) reduced H-3 cocaine striatum-to-cerebellum ratios (St/Cb, {lg_bullet}) from 1.6 to 1.2 at 3 h after administration, with recovery by 12 h. In the present study we demonstrate a very similar time-course for transport {triangle} measured in striatal homo within 2 min of sacrifice. The maximum inhibition of uptake at about 1 h corresponded to about 80% of the control uptake rate, similar to the percent reduction in St/Cb. The time-course of the effect of this dose of RTI-55 on locomotor activity ({sq_bullet}) was complex, with a drop in the activity measure at 7 h, after a further injection of RTI-55, but activity remained higher than in saline controls. In spite of this complexity, which may be associated with stereotypies and/or exhaustion, the duration of increased activity is consistent with the duration of transporter blockade. These experiments support the notion that PET/SPECT measures of transporter occupancy accurately reflect transporter inhibition.

  19. Ex-vivo in-vitro inhibition of lipopolysaccharide stimulated tumor necrosis factor-alpha and interleukin-1 beta secretion in human whole blood by extractum urticae dioicae foliorum.

    PubMed

    Obertreis, B; Ruttkowski, T; Teucher, T; Behnke, B; Schmitz, H

    1996-04-01

    An extract of Urtica dioica folium (IDS 23, Rheuma-Hek), monographed positively for adjuvant therapy of rheumatic diseases and with known effects in partial inhibition of prostaglandin and leukotriene synthesis in vitro, was investigated with respect to effects of the extract on the lipopolysaccharide (LPS) stimulated secretion of proinflammatory cytokines in human whole blood of healthy volunteers. In the assay system used, LPS stimulated human whole blood showed a straight increase of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion reaching maximum concentrations within 24 h following a plateau and slight decrease up to 65 h, respectively. The concentrations of these cytokines was strongly positively correlated with the number of monocytes/macrophages of each volunteer. TNF-alpha and IL-1 beta concentration after LPS stimulation was significantly reduced by simultaneously given IDS 23 in a strictly dose dependent manner. At time 24 h these cytokine concentrations were reduced by 50.8% and 99.7%, respectively, using the highest test IDS 23 assay concentration of 5 mg/ml (p < 0.001). After 65 h the corresponding inhibition was 38.9% and 99.9%, respectively (p < 0.001). On the other hand IDS 23 showed no inhibition but stimulated IL-6 secretion in absence of LPS alone. Simultaneously given LPS and IDS 23 resulted in no further increase. In contrast to described effects on arachidonic acid cascade in vitro, tested Urtica dioica phenol carbon acid derivates and flavonoides such as caffeic malic acid, caffeic acid, chlorogenic acid, quercetin and rutin did not influence LPS stimulated TNF-alpha, IL-1 beta and IL-6 secretion in tested concentrations up to 5 x 10(-5) mol/l. These further findings on the pharmacological mechanism of action of Urticae dioica folia may explain the positive effects of this extract in the treatment of rheumatic diseases. PMID:8740085

  20. Lipid oxidation in trout muscle is strongly inhibited by a protein that specifically binds hemin released from hemoglobin

    PubMed Central

    Cai, He; Grunwald, Eric W; Park, Sungyong; Lei, Benfang; Richards, Mark P.

    2013-01-01

    The recombinant Streptococcal protein apoShp can be used as a probe for hemoglobin (Hb) reactivity in fish muscle due to its specific affinity for hemin that is released from Hb at post mortem pH values. Hemin affinity measurements indicated that apoShp binds hemin released from Hb but not myoglobin (Mb). Hemin affinity of holoShp was higher at pH 5.7 compared to pH 8.0. This may be attributed to enhanced electrostatic interaction of His58 with the heme-7-propionate at lower pH. ApoShp readily acquired hemin that was released from trout IV metHb in the presence of washed cod muscle during 2°C storage at pH 6.3. This was based on increases in redness in the washed cod matrix which occurs when apoShp binds hemin that is released from metHb. ApoShp prevented Hb-mediated lipid oxidation in washed cod muscle during 2°C storage. The prevention of Hb-mediated lipid oxidation by apoShp was likely due to bis-methionyl coordination of hemin that dissociated from metHb. This hexa-coordination of hemin appears to prevent peroxide-mediated redox reactions and there is no component in the matrix capable of dissociating hemin from Shp. ApoShp was also added to minced muscle from Rainbow trout (Oncorhynchus mykiss) to examine the degree to which Hb contributes to lipid oxidation in trout muscle. Addition of apoShp inhibited approximately 90% of the lipid oxidation that occurred in minced trout muscle during 9 days of 2°C storage based on lipid peroxide, hexanal, and thiobarituric acid reactive substances (TBARS) values. These results strongly suggest that Hb is the primary promoter of lipid oxidation in trout muscle. PMID:23570608

  1. Blocking antibody to the β-subunit of FSH prevents bone loss by inhibiting bone resorption and stimulating bone synthesis

    PubMed Central

    Zhu, Ling-Ling; Blair, Harry; Cao, Jay; Yuen, Tony; Latif, Rauf; Guo, Lida; Tourkova, Irina L.; Li, Jianhua; Davies, Terry F.; Sun, Li; Bian, Zhuan; Rosen, Clifford; Zallone, Alberta; New, Maria I.; Zaidi, Mone

    2012-01-01

    Low estrogen levels undoubtedly underlie menopausal bone thinning. However, rapid and profuse bone loss begins 3 y before the last menstrual period, when serum estrogen is relatively normal. We have shown that the pituitary hormone FSH, the levels of which are high during late perimenopause, directly stimulates bone resorption by osteoclasts. Here, we generated and characterized a polyclonal antibody to a 13-amino-acid-long peptide sequence within the receptor-binding domain of the FSH β-subunit. We show that the FSH antibody binds FSH specifically and blocks its action on osteoclast formation in vitro. When injected into ovariectomized mice, the FSH antibody attenuates bone loss significantly not only by inhibiting bone resorption, but also by stimulating bone formation, a yet uncharacterized action of FSH that we report herein. Mesenchymal cells isolated from mice treated with the FSH antibody show greater osteoblast precursor colony counts, similarly to mesenchymal cells isolated from FSH receptor (FSHR)−/− mice. This suggests that FSH negatively regulates osteoblast number. We confirm that this action is mediated by signaling-efficient FSHRs present on mesenchymal stem cells. Overall, the data prompt the future development of an FSH-blocking agent as a means of uncoupling bone formation and bone resorption to a therapeutic advantage in humans. PMID:22908268

  2. Serum-Stimulated Release of Cell Contacts and the Initiation of Growth in Contact-Inhibited Chick Fibroblasts

    PubMed Central

    Baker, Joffre B.; Humphreys, Tom

    1971-01-01

    Increased serum concentration in the medium of a confluent culture increases the overlapping of cells and the average rate of cell movement. The relationship between these two serum activities and serum release of growth inhibition was studied. The increase in overlaps does not appear to be directly related to release of growth since it occurs well after growth has been initiated. The increased rate of cell movement occurred immediately after the addition of serum and was quantitatively proportional to the stimulation of DNA synthesis over a range of serum concentrations, implying that both movement and growth are released by a common serum activity. Direct microscopic observation and time-lapse films reveal a reduction in cell contacts concurrent with the increase in cell movement. Experiments showed that cell movement at low cell densities, where cell contacts are minimal, was rapid in low serum concentration and was not stimulated by increasing the serum concentration. This suggests that the serum effect on cell movement involves cell contacts and is due to release of cell contacts in the confluent monolayer. The primary action of serum may be the disruption of adhesive cell contacts. Images PMID:4943788

  3. Roflumilast inhibits the release of chemokines and TNF-α from human lung macrophages stimulated with lipopolysaccharide

    PubMed Central

    Buenestado, A; Grassin-Delyle, S; Guitard, F; Naline, E; Faisy, C; Israël-Biet, D; Sage, E; Bellamy, JF; Tenor, H; Devillier, P

    2012-01-01

    BACKGROUND AND PURPOSE Lung macrophages are critically involved in respiratory diseases. This study assessed the effects of the PDE4 inhibitor roflumilast and its active metabolite, roflumilast N-oxide on the release of a range of chemokines (CCL2, 3, 4, CXCL1, 8, 10) and of TNF-α, from human lung macrophages, stimulated with bacterial lipopolysaccharide LPS. EXPERIMENTAL APPROACH Lung macrophages isolated from resected human lungs were incubated with roflumilast, roflumilast N-oxide, PGE2, the COX inhibitor indomethacin, the COX-2 inhibitor NS-398 or vehicle and stimulated with LPS (24 h). Chemokines, TNF-α, PGE2 and 6-keto PGF1α were measured in culture supernatants by immunoassay. COX-2 mRNA expression was assessed with RT-qPCR. PDE activities were determined in macrophage homogenates. KEY RESULTS Expression of PDE4 in lung macrophages was increased after incubation with LPS. Roflumilast and roflumilast N-oxide concentration-dependently reduced the LPS-stimulated release of CCL2, CCL3, CCL4, CXCL10 and TNF-α from human lung macrophages, whereas that of CXCL1 or CXCL8 was not altered. This reduction by the PDE4 inhibitors was further accentuated by exogenous PGE2 (10 nM) but abolished in the presence of indomethacin or NS-398. Conversely, addition of PGE2 (10 nM), in the presence of indomethacin restored inhibition by roflumilast. LPS also increased PGE2 and 6-keto PGF1α release from lung macrophages which was associated with an up-regulation of COX-2 mRNA. CONCLUSIONS AND IMPLICATIONS Roflumilast and roflumilast N-oxide reduced LPS-induced release of CCL2, 3, 4, CXCL10 and TNF-α in human lung macrophages. PMID:21913898

  4. Aqueous extracts of Cimicifuga racemosa and phenolcarboxylic constituents inhibit production of proinflammatory cytokines in LPS-stimulated human whole blood.

    PubMed

    Schmid, Diethart; Woehs, Florian; Svoboda, Martin; Thalhammer, Theresia; Chiba, Peter; Moeslinger, Thomas

    2009-11-01

    Cimicifuga racemosa (black cohosh) is commonly used in traditional medicines as treatment for menopausal symptoms and as an antiinflammatory remedy. To clarify the mechanism of action and active principle for the antiinflammatory action, the effects of aqueous C. racemosa root extracts (CRE) and its major constituents on the release of the proinflammatory cytokines IL-6, TNF-alpha, IFN-gamma, and the chemokine IL-8 were investigated in lipopolysaccharide (LPS)-stimulated whole blood of healthy volunteers. CRE (3 microg/microL and 6 microg/microL) reduced LPS-induced release of IL-6 and TNF-alpha in a concentration- and time-dependent manner and almost completely blocked release of IFN-gamma into the plasma supernatant. Except for IFN-gamma, these effects were attenuated at longer incubation periods. IL-8 secretion was stimulated by CRE. As shown by quantitative real-time RT-PCR, effects on cytokines were based on preceding changes in mRNA levels except for IL-8. According to their content in CRE, the phenolcarboxylic compounds caffeic acid, ferulic acid, and isoferulic acid, as well as the triterpene glycosides 23-epi-26-deoxyactein and cimigenol-3-O-xyloside, were tested at representative concentrations. Among these, isoferulic acid was the prominent active principle in CRE, responsible for the observed inhibition of IL-6, TNF-alpha, and IFN-gamma, but not for IL-8 stimulation. The effect of this compound may explain the antiinflammatory activities of CRE and its beneficial actions in rheumatism and other inflammatory diseases. PMID:19935904

  5. Neomycin inhibits the phosphatidylinositol monophosphate and phosphatidylinositol bisphosphate stimulation of plasma membrane ATPase activity

    SciTech Connect

    Chen, Qiuyun; Boss, W.F. )

    1991-05-01

    The inositol phospholipids, phosphatidylinositol monophosphate (PIP) and phosphatidylinositol bisphosphate (PIP{sub 2}), have been shown to increase the vanadate-sensitive ATPase activity of plant plasma membranes. In this paper, the authors show the effect of various concentrations of phosphatidyinositol, PIP, and PIP{sub 2} on the plasma membrane vanadate-sensitive ATPase activity. PIP and PIP{sub 2} at concentrations at 10 nanomoles per 30 microgram membrane protein per milliliter of reaction mixture caused a twofold and 1.8-fold increase in the ATPase activity, respectively. The effect of these negatively charged phospholipids on the ATPase activity was inhibited by adding the positively charged aminoglycoside, neomycin. Neomycin did not affect the endogenous plasma membrane ATPase activity in the absence of exogenous lipids.

  6. Stimulation and inhibition of corticotrophin releasing factor secretion by beta endorphin.

    PubMed

    Buckingham, J C

    1986-01-01

    The influence of beta-endorphin on the secretion of corticotrophin releasing factor (CRF) by isolated rat hypothalami in vitro was studied. beta-Endorphin (10(-11)-10(-10) M) caused dose-related increases in the CRF contents of the hypothalami and of the medium in which they were incubated. Its effects were antagonized by naloxone (10(-8)-10(-7) M). In contrast, in higher concentrations (10(-7) - 10(-5) M), it reduced, in a dose-dependent manner, both the spontaneous release of CRF from the hypothalami and the release which normally occurred in response to acetylcholine, 5-hydroxytryptamine, morphine, met-enkephalin and leu-enkephalin. The inhibition of CRF release was associated with a rise in the tissue content of the hormone and was not blocked readily by naloxone. The results support the concept that opioid substances may be involved in the control of hypothalamo-pituitary-adrenocortical function. PMID:2936971

  7. Transient exposure of human myoblasts to tumor necrosis factor-alpha inhibits serum and insulin-like growth factor-I stimulated protein synthesis.

    PubMed

    Frost, R A; Lang, C H; Gelato, M C

    1997-10-01

    Tumor necrosis factor-alpha (TNF-alpha) induces cachexia and is postulated to be responsible for muscle wasting in several pathophysiological conditions. The purpose of the present study was to investigate whether exposure of human myoblasts to TNF-alpha could directly inhibit the ability of serum or insulin-like growth factor I (IGF-I) to stimulate protein synthesis as assessed by the incorporation of [3H]phenylalanine into protein. Serum and IGF-I stimulated protein synthesis dose dependently. Half-maximal stimulation of protein synthesis occurred at 05% serum and 8 ng/ml of IGF-I, respectively. TNF-alpha inhibited IGF-I-stimulated protein synthesis in a dose-dependent manner. Additionally, as little as 2 ng/ml of TNF-alpha impaired the ability of IGF-I to stimulate protein synthesis by 33% and, at a dose of 100 ng/ml, TNF-alpha completely prevented the increase in protein synthesis induced by either serum or a maximally stimulating dose of IGF-I. Inhibition of protein synthesis was independent of whether TNF-alpha and growth factors were added to cells simultaneously or if the cells were pretreated with growth factors. Exposure ofmyoblasts to TNF-alpha for 10 min completely inhibited serum-induced stimulation of protein synthesis. TNF-alpha inhibited protein synthesis up to 48 h after addition of the cytokine. TNF-alpha also inhibited serum-stimulated protein synthesis in human myoblasts that were differentiated into myotubes. In contrast, exposure of myoblasts to TNF-alpha had no effect on IGF-I binding and failed to alter the ability of either IGF-I or serum to stimulate [3H]thymidine uptake. These data indicate that transient exposure of myoblasts or myotubes to TNF-alpha inhibits protein synthesis. Thus, the anabolic actions of IGF-I on muscle protein synthesis may be impaired during catabolic conditions in which TNF-alpha is over expressed. PMID:9322924

  8. An RNA polymerase II transcription factor has an associated DNA-dependent ATPase (dATPase) activity strongly stimulated by the TATA region of promoters.

    PubMed Central

    Conaway, R C; Conaway, J W

    1989-01-01

    A transcription factor required for synthesis of accurately initiated run-off transcripts by RNA polymerase II has been purified and shown to have an associated DNA-dependent ATPase (dATPase) activity that is strongly stimulated by the TATA region of promoters. This transcription factor, designated delta, was purified more than 3000-fold from extracts of crude rat liver nuclei and has a native molecular mass of approximately 230 kDa. DNA-dependent ATPase (dATPase) and transcription activities copurify when delta is analyzed by hydrophobic interaction and ion-exchange HPLC, arguing that transcription factor delta possesses an ATPase (dATPase) activity. ATPase (dATPase) is specific for adenine nucleotides; ATP and dATP, but not CTP, UTP, or GTP, are hydrolyzed. ATPase (dATPase) is stimulated by both double-stranded and single-stranded DNAs, including pUC18, ssM13, and poly(dT); however, DNA fragments containing the TATA region of either the adenovirus 2 major late or mouse interleukin 3 promoters stimulate ATPase as much as 10-fold more effectively than DNA fragments containing nonpromoter sequences. These data suggest the intriguing possibility that delta plays a critical role in the ATP (dATP)-dependent activation of run-off transcription through a direct interaction with the TATA region of promoters. Images PMID:2552440

  9. MicroRNA-194 reciprocally stimulates osteogenesis and inhibits adipogenesis via regulating COUP-TFII expression

    PubMed Central

    Jeong, B-C; Kang, I-H; Hwang, Y-C; Kim, S-H; Koh, J-T

    2014-01-01

    Osteoblasts and adipocytes are differentiated from common mesenchymal stem cells (MSCs) in processes which are tightly controlled by various growth factors, signaling molecules, transcriptional factors and microRNAs. Recently, chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) was identified as a critical regulator of MSC fate. In the present study, we aimed to identify some microRNAs (miR), which target COUP-TFII, and to determine the effects on MSCs fate. During osteoblastic or adipocytic differentiation from MSCs lineage cells, miR-194 expression was found to be reversal. In the cultures of mesenchymal C3H10T1/2 and primary bone marrow stromal cells, osteogenic stimuli increased miR-194 expression with accompanying decreases in COUP-TFII expression, whereas adipogenic stimuli reduced miR-194 expression with accompanying increases in COUP-TFII expression. A luciferase assay with COUP-TFII 3′-untranslated region (UTR) reporter plasmid, including the miR-194 binding sequences, showed that the introduction of miR-194 reduced the luciferase activity. However, it did not affect the activity of mutated COUP-TFII 3′-UTR reporter. Enforced expression of miR-194 significantly enhanced osteoblast differentiation, but inhibited adipocyte differentiation by decreasing COUP-TFII mRNA and protein levels. In contrast, inhibition of the endogenous miR-194 reduced matrix mineralization in the MSCs cultures, promoting the formation of lipid droplets by rescuing COUP-TFII expression. Furthermore, overexpression of COUP-TFII reversed the effects of miR-194 on the cell fates. Taken together, our results showed that miR-194 acts as a critical regulator of COUP-TFII, and can determinate the fate of MSCs to differentiate into osteoblasts and adipocytes. This suggests that miR-194 and COUP-TFII may be good target molecules for controlling bone and metabolic diseases. PMID:25412310

  10. Diacylglycerol pyrophosphate inhibits the alpha-amylase secretion stimulated by gibberellic acid in barley aleurone.

    PubMed

    Racagni, Graciela; Villasuso, Ana L; Pasquaré, Susana J; Giusto, Norma M; Machado, Estela

    2008-11-01

    ABA plays an important regulatory role in seed germination because it inhibits the response to GA in aleurone, a secretory tissue surrounding the endosperm. Phosphatidic acid (PA) is a well-known intermediary in ABA signaling, but the role of diacylglycerol pyrophosphate (DGPP) in germination processes is not clearly established. In this study, we show that PA produced by phospholipase D (E.C. 3.1.4.4) during the antagonist effect of ABA in GA signaling is rapidly phosphorylated by phosphatidate kinase (PAK) to DGPP. This is a crucial fact for aleurone function because exogenously added dioleoyl-DGPP inhibits secretion of alpha-amylase (E.C. 3.2.1.1). Aleurone treatment with ABA and 1-butanol results in normal secretory activity, and this effect is reversed by addition of dioleoyl-DGPP. We also found that ABA decreased the activity of an Mg2+-independent, N-ethylmaleimide-insensitive form of phosphatidate phosphohydrolase (PAP2) (E.C. 3.1.3.4), leading to reduction of PA dephosphorylation and increased PAK activity. Sequence analysis using Arabidopsis thaliana lipid phosphate phosphatase (LPP) sequences as queries identified two putative molecular homologues, termed HvLPP1 and HvLPP2, encoding putative Lpps with the presence of well-conserved structural Lpp domains. Our results are consistent with a role of DGPP as a regulator of ABA antagonist effect in GA signaling and provide evidence about regulation of PA level by a PAP2 during ABA response in aleurone. PMID:18573189