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Sample records for endothelin a-receptor blockade

  1. Endothelin A-receptor blockade in experimental diabetes improves glucose balance and gastrointestinal function.

    PubMed

    Balsiger, Bruno; Rickenbacher, Andreas; Boden, Penelope Jane; Biecker, Erwin; Tsui, Janice; Dashwood, Michael; Reichen, Jürg; Shaw, Sidney George

    2002-08-01

    Secondary complications of diabetes mellitus often involve gastrointestinal dysfunction. In the experimental Goto Kakizaki rat, a model of Type II diabetes, hyperglycaemia and reduced glucose clearance is associated with elevated plasma endothelin (ET)-1 levels and selective decreases in nitric oxide synthase in circular muscle, longitudinal muscle and neuronal elements of the gastrointestinal tract. Functionally, this is accompanied by decreased nitrergic relaxatory responses of jejunal longitudinal muscle to tetrodotoxin-sensitive electrical field stimulation. Long-term treatment with a selective ET A-type receptor antagonist, markedly reduced hyperglycaemia and restored plasma glucose clearance rates towards normal. This was associated with a restoration of N(G)-nitro-L-arginine methyl ester-sensitive relaxatory responses of jejunal longitudinal muscle to electrical field stimulation. The results indicate that beneficial effects of ETA receptor blockade on gastrointestinal function may result from an improvement in insulin sensitivity with concomitant reduction of the severity of hyperglycaemia. ETA receptor blockade may represent a new therapeutic principle for improving glucose tolerance in Type II diabetes and could be beneficial in alleviating or preventing hyperglycaemia-related secondary complications in this condition.

  2. Up-Regulation of Endothelin Type A Receptor in Human and Rat Radiation Proctitis: Preclinical Therapeutic Approach With Endothelin Receptor Blockade

    SciTech Connect

    Jullien, Nicolash; Blirando, Karl; Milliat, Fabien; Benderitter, Marc; Francois, Agnes

    2009-06-01

    Purpose: Rectum radiation damage and fibrosis are often associated with radiation therapy of pelvic tumors. The endothelin (ET) system has been implicated in several fibrotic diseases but never studied in the context of gastrointestinal radiation damage. This study assessed modifications in ET type 1 (ET-1), ET type A receptor (ET{sub A}), and ET type B receptor (ET{sub B}) localization and/or expression in irradiated human rectal tissue and in a rat model of delayed colorectal injury. We also evaluated the therapeutic potential of long-term ET receptor blockade. Methods and Materials: Routine histological studies of sections of healthy and radiation-injured human rectum tissue were done; the sections were also immunostained for ET{sub A} and ET{sub B} receptors. The rat model involved the delivery of 27 Gy in a single dose to the colons and rectums of the animals. The ET-1/ET{sub A}/ET{sub B} expression and ET{sub A}/ET{sub B} localization were studied at 10 weeks postexposure. The abilities of bosentan and atrasentan to protect against delayed rectal injury were also investigated. Results: The immunolocalization of ET{sub A} and ET{sub B} in healthy human rectums was similar to that in rat rectums. However, strong ET{sub A} immunostaining was seen in the presence of human radiation proctitis, and increased ET{sub A} mRNA levels were seen in the rat following colorectal irradiation. Immunostaining for ET{sub A} was also strongly positive in rats in areas of radiation-induced mucosal ulceration, atypia, and fibroproliferation. However, neither bosentan nor atrasentan prevented radiation damage to the rectum when given long term. The only effect seen for atrasentan was an increased number of sclerotic vessel sections in injured tissues. Conclusions: As the result of the overexpression of ET{sub A}, radiation exposure deregulates the endothelin system through an 'ET{sub A} profile' in the human and rodent rectum. However, therapeutic interventions involving mixed or

  3. Selective blockade of the endothelin subtype A receptor decreases early atherosclerosis in hamsters fed cholesterol.

    PubMed Central

    Kowala, M. C.; Rose, P. M.; Stein, P. D.; Goller, N.; Recce, R.; Beyer, S.; Valentine, M.; Barton, D.; Durham, S. K.

    1995-01-01

    Recent studies suggest that endothelin and its receptors may be involved in atherogenesis. To test this hypothesis, cholesterol-fed hamsters were treated with a selective endothelin subtype A (ETA) receptor antagonist BMS-182874. Characterization of hamster atherosclerotic plaques indicated that they contained a fibrous cap of smooth muscle cells, large macrophage-foam cells, and epitopes of oxidized low density lipoprotein. Messenger RNA for both ETA and ETB receptors was detected in aortic endothelial cells, in medial smooth muscle cells, and in macrophage-foam cells and smooth muscle cells of the fibro-fatty plaques. BMS-182874 inhibited the endothelin-1-induced pressor response whereas the depressor effect was unaltered, suggesting that vascular ETA receptors were selectively blocked in vivo. In hyperlipidemic hamsters, BMS-182874 decreased the area of the fatty streak by reducing the number and size of macrophage-foam cells. The results indicated that ETA receptors and thus endothelin promoted the early inflammatory phase of atherosclerosis. Images Figure 1 Figure 2 Figure 3 Figure 5 PMID:7717449

  4. Endothelin receptor a blockade is an ineffective treatment for adriamycin nephropathy.

    PubMed

    Tan, Roderick J; Zhou, Lili; Zhou, Dong; Lin, Lin; Liu, Youhua

    2013-01-01

    Endothelin is a vasoconstricting peptide that plays a key role in vascular homeostasis, exerting its biologic effects via two receptors, the endothelin receptor A (ETA) and endothelin receptor B (ETB). Activation of ETA and ETB has opposing actions, in which hyperactive ETA is generally vasoconstrictive and pathologic. Selective ETA blockade has been shown to be beneficial in renal injuries such as diabetic nephropathy and can improve proteinuria. Atrasentan is a selective pharmacologic ETA blocker that preferentially inhibits ETA activation. In this study, we evaluated the efficacy of ETA blockade by atrasentan in ameliorating proteinuria and kidney injury in murine adriamycin nephropathy, a model of human focal segmental glomerulosclerosis. We found that ETA expression was unaltered during the course of adriamycin nephropathy. Whether initiated prior to injury in a prevention protocol (5 mg/kg/day, i.p.) or after injury onset in a therapeutic protocol (7 mg/kg or 20 mg/kg three times a week, i.p.), atrasentan did not significantly affect the initiation and progression of adriamycin-induced albuminuria (as measured by urinary albumin-to-creatinine ratios). Indices of glomerular damage were also not improved in atrasentan-treated groups, in either the prevention or therapeutic protocols. Atrasentan also failed to improve kidney function as determined by serum creatinine, histologic damage, and mRNA expression of numerous fibrosis-related genes such as collagen-I and TGF-β1. Therefore, we conclude that selective blockade of ETA by atrasentan has no effect on preventing or ameliorating proteinuria and kidney injury in adriamycin nephropathy.

  5. Endothelin A receptor activation on mesangial cells initiates Alport glomerular disease.

    PubMed

    Dufek, Brianna; Meehan, Daniel T; Delimont, Duane; Cheung, Linda; Gratton, Michael Anne; Phillips, Grady; Song, Wenping; Liu, Shiguang; Cosgrove, Dominic

    2016-08-01

    Recent work demonstrates that Alport glomerular disease is mediated through a biomechanical strain-sensitive activation of mesangial actin dynamics. This occurs through a Rac1/CDC42 cross-talk mechanism that results in the invasion of the subcapillary spaces by mesangial filopodia. The filopodia deposit mesangial matrix proteins in the glomerular basement membrane, including laminin 211, which activates focal adhesion kinase in podocytes culminating in the up-regulation of proinflammatory cytokines and metalloproteinases. These events drive the progression of glomerulonephritis. Here we test whether endothelial cell-derived endothelin-1 is up-regulated in Alport glomeruli and further elevated by hypertension. Treatment of cultured mesangial cells with endothelin-1 activates the formation of drebrin-positive actin microspikes. These microspikes do not form when cells are treated with the endothelin A receptor antagonist sitaxentan or under conditions of small, interfering RNA knockdown of endothelin A receptor mRNA. Treatment of Alport mice with sitaxentan results in delayed onset of proteinuria, normalized glomerular basement membrane morphology, inhibition of mesangial filopodial invasion of the glomerular capillaries, normalization of glomerular expression of metalloproteinases and proinflammatory cytokines, increased life span, and prevention of glomerulosclerosis and interstitial fibrosis. Thus endothelin A receptor activation on mesangial cells is a key event in initiation of Alport glomerular disease in this model.

  6. ENDOTHELIN-A RECEPTOR ANTAGONISM IN EMBRYO CULTURE: WINDOW OF SENSITIVITY AND TIMING OF DEFECT

    EPA Science Inventory

    BRANNEN, K.C., J.M. ROGERS, and E.S. HUNTER, Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina, and Reproductive Toxicology Division, NHEERL, U.S. EPA, Research Triangle Park, North Carolina. Endothelin-A receptor antagonism in embryo culture: w...

  7. Endothelin

    PubMed Central

    Hyndman, Kelly A.; Dhaun, Neeraj; Southan, Christopher; Kohan, Donald E.; Pollock, Jennifer S.; Pollock, David M.; Webb, David J.; Maguire, Janet J.

    2016-01-01

    The endothelins comprise three structurally similar 21-amino acid peptides. Endothelin-1 and -2 activate two G-protein coupled receptors, ETA and ETB, with equal affinity, whereas endothelin-3 has a lower affinity for the ETA subtype. Genes encoding the peptides are present only among vertebrates. The ligand-receptor signaling pathway is a vertebrate innovation and may reflect the evolution of endothelin-1 as the most potent vasoconstrictor in the human cardiovascular system with remarkably long lasting action. Highly selective peptide ETA and ETB antagonists and ETB agonists together with radiolabeled analogs have accurately delineated endothelin pharmacology in humans and animal models, although surprisingly no ETA agonist has been discovered. ET antagonists (bosentan, ambrisentan) have revolutionized the treatment of pulmonary arterial hypertension, with the next generation of antagonists exhibiting improved efficacy (macitentan). Clinical trials continue to explore new applications, particularly in renal failure and for reducing proteinuria in diabetic nephropathy. Translational studies suggest a potential benefit of ETB agonists in chemotherapy and neuroprotection. However, demonstrating clinical efficacy of combined inhibitors of the endothelin converting enzyme and neutral endopeptidase has proved elusive. Over 28 genetic modifications have been made to the ET system in mice through global or cell-specific knockouts, knock ins, or alterations in gene expression of endothelin ligands or their target receptors. These studies have identified key roles for the endothelin isoforms and new therapeutic targets in development, fluid-electrolyte homeostasis, and cardiovascular and neuronal function. For the future, novel pharmacological strategies are emerging via small molecule epigenetic modulators, biologicals such as ETB monoclonal antibodies and the potential of signaling pathway biased agonists and antagonists. PMID:26956245

  8. Dual Endothelin Receptor Blockade Abrogates Right Ventricular Remodeling and Biventricular Fibrosis in Isolated Elevated Right Ventricular Afterload

    PubMed Central

    Nielsen, Eva Amalie; Sun, Mei; Honjo, Osami; Hjortdal, Vibeke E.; Redington, Andrew N.; Friedberg, Mark K.

    2016-01-01

    Background Pulmonary arterial hypertension is usually fatal due to right ventricular failure and is frequently associated with co-existing left ventricular dysfunction. Endothelin-1 is a powerful pro-fibrotic mediator and vasoconstrictor that is elevated in pulmonary arterial hypertension. Endothelin receptor blockers are commonly used as pulmonary vasodilators, however their effect on biventricular injury, remodeling and function, despite elevated isolated right ventricular afterload is unknown. Methods Elevated right ventricular afterload was induced by progressive pulmonary artery banding. Seven rabbits underwent pulmonary artery banding without macitentan; 13 received pulmonary artery banding + macitentan; and 5 did not undergo inflation of the pulmonary artery band (sham-operated controls). Results: Right and left ventricular collagen content was increased with pulmonary artery banding compared to sham-operated controls and ameliorated by macitentan. Right ventricular fibrosis signaling (connective tissue growth factor and endothelin-1 protein levels); extra-cellular matrix remodeling (matrix-metalloproteinases 2 and 9), apoptosis and apoptosis-related peptides (caspases 3 and 8) were increased with pulmonary artery banding compared with sham-operated controls and decreased with macitentan. Conclusion Isolated right ventricular afterload causes biventricular fibrosis, right ventricular apoptosis and extra cellular matrix remodeling, mediated by up-regulation of endothelin-1 and connective tissue growth factor signaling. These pathological changes are ameliorated by dual endothelin receptor blockade despite persistent elevated right ventricular afterload. PMID:26765263

  9. Selective endothelin B receptor blockade does not influence BNP-induced natriuresis in man.

    PubMed

    van der Zander, K; Houben, A J H M; Webb, D J; Udo, E; Kietselaer, B; Hofstra, L; De Mey, J G R; de Leeuw, P W

    2006-03-01

    Brain natriuretic peptide (BNP) and endothelin-1 (ET-1) both exhibit natriuretic activity within the human kidney. Furthermore, they both act partly through activation of the endothelial nitric oxide pathway. Since ET-1 may cause vasodilation and natriuresis via stimulation of the ET-B receptor, the aim of the present study was to investigate whether renal ET-B receptors participate in the renal actions of BNP. In this placebo-controlled, crossover study, we infused BNP (4 pmol/kg/min) or placebo (i.v.) for 1 h, with or without co-infusion of the ET-B receptor antagonist BQ-788 (50 nmol/min) for 15 min on 4 separate days, in 10 healthy subjects (mean age 54+/-6 years.). During infusion, we measured effective renal plasma flow (ERPF), and glomerular filtration rate (GFR) using PAH/inulin clearance. Cardiac output was measured before and after infusion, using echocardiography. Blood pressure and heart rate (HR) were monitored as well. Urine and plasma samples were taken every hour to measure diuresis, natriuresis, cyclic 3',5' guanosine monophosphate, and ET-1 levels. BNP with or without ET-B receptor blockade increased natriuresis and diuresis. In addition, BNP alone increased GFR and filtered load, without changing ERPF. BQ-788 infusion did not affect renal hemodynamics or natriuresis. Neither BNP nor BQ-788 altered cardiac output, blood pressure, and heart rate. In conclusion, the present study shows that selective ET-B receptor blockade has no effect on the BNP-induced natriuresis and glomerular filtration rate.

  10. Impact of endothelin blockade on acute exercise-induced changes in blood flow and endothelial function in type 2 diabetes mellitus.

    PubMed

    Schreuder, Tim H A; van Lotringen, Jaap H; Hopman, Maria T E; Thijssen, Dick H J

    2014-09-01

    Positive vascular effects of exercise training are mediated by acute increases in blood flow. Type 2 diabetes patients show attenuated exercise-induced increases in blood flow, possibly mediated by the endothelin pathway, preventing an optimal stimulus for vascular adaptation. We examined the impact of endothelin receptor blockade (bosentan) on exercise-induced blood flow in the brachial artery and on pre- and postexercise endothelial function in type 2 diabetes patients (n = 9, 60 ± 7 years old) and control subjects (n = 10, 60 ± 5 years old). Subjects reported twice to the laboratory to perform hand-grip exercise in the presence of endothelin receptor blockade or placebo. We examined brachial artery endothelial function (via flow-mediated dilatation) before and after exercise, as well as blood flow during exercise. Endothelin receptor blockade resulted in a larger increase in blood flow during exercise in type 2 diabetes patients (P = 0.046), but not in control subjects (P = 0.309). Exercise increased shear rate across the exercise protocol, unaffected by endothelin receptor blockade. Exercise did not alter brachial artery diameter in either group, but endothelin receptor blockade resulted in a larger brachial artery diameter in type 2 diabetes patients (P = 0.033). Exercise significantly increased brachial artery flow-mediated dilatation in both groups, unaffected by endothelin receptor blockade. Endothelin receptor blockade increased exercise-induced brachial artery blood flow in type 2 diabetes patients, but not in control subjects. Despite this effect of endothelin receptor blockade on blood flow, we found no impact on baseline or post-exercise endothelial function in type 2 diabetes patients or control subjects, possibly related to normalization of the shear stimulus during exercise. The successful increase in blood flow during exercise in type 2 diabetes patients through endothelin receptor blockade may have beneficial effects in

  11. Involvement of α₂-adrenoceptors, imidazoline, and endothelin-A receptors in the effect of agmatine on morphine and oxycodone-induced hypothermia in mice.

    PubMed

    Bhalla, Shaifali; Andurkar, Shridhar V; Gulati, Anil

    2013-10-01

    Potentiation of opioid analgesia by endothelin-A (ET(A)) receptor antagonist, BMS182874, and imidazoline receptor/α₂-adrenoceptor agonists such as clonidine and agmatine are well known. It is also known that agmatine blocks morphine hyperthermia in rats. However, the effect of agmatine on morphine or oxycodone hypothermia in mice is unknown. The present study was carried out to study the role of α₂-adrenoceptors, imidazoline, and ET(A) receptors in morphine and oxycodone hypothermia in mice. Body temperature was determined over 6 h in male Swiss Webster mice treated with morphine, oxycodone, agmatine, and combination of agmatine with morphine or oxycodone. Yohimbine, idazoxan, and BMS182874 were used to determine involvement of α₂-adrenoceptors, imidazoline, and ET(A) receptors, respectively. Morphine and oxycodone produced significant hypothermia that was not affected by α₂-adrenoceptor antagonist yohimbine, imidazoline receptor/α₂ adrenoceptor antagonist idazoxan, or ET(A) receptor antagonist, BMS182874. Agmatine did not produce hypothermia; however, it blocked oxycodone but not morphine-induced hypothermia. Agmatine-induced blockade of oxycodone hypothermia was inhibited by idazoxan and yohimbine. The blockade by idazoxan was more pronounced compared with yohimbine. Combined administration of BMS182874 and agmatine did not produce changes in body temperature in mice. However, when BMS182874 was administered along with agmatine and oxycodone, it blocked agmatine-induced reversal of oxycodone hypothermia. This is the first report demonstrating that agmatine does not affect morphine hypothermia in mice, but reverses oxycodone hypothermia. Imidazoline receptors and α₂-adrenoceptors are involved in agmatine-induced reversal of oxycodone hypothermia. Our findings also suggest that ET(A) receptors may be involved in blockade of oxycodone hypothermia by agmatine.

  12. Plasma endothelin-1 and single nucleotide polymorphisms of endothelin-1 and endothelin type A receptor genes as risk factors for normal tension glaucoma

    PubMed Central

    Kosior-Jarecka, Ewa; Łukasik, Urszula; Aung, Tin; Khor, Chiea Chuen; Kocki, Janusz; Żarnowski, Tomasz

    2016-01-01

    Purpose The purpose of this study was to determine whether four single nucleotide polymorphisms (SNPs) of endothelin and endothelin receptor type A genes can constitute a risk factor for normal tension glaucoma (NTG) and high tension glaucoma (HTG). Methods The study included 160 patients with NTG, 124 patients with HTG, and 165 healthy controls. To analyze the frequency of polymorphic variants of the endothelin EDN gene (K198N) and the endothelin receptor type A gene EDN RA (C1222T, C70G, G231A), DNA was isolated from peripheral blood, and SNP genotyping was performed using the real-time PCR (RT–PCR) method. Plasma endothelin (ET) concentrations were detected using an enzyme immunoassay. Endothelin levels were compared with genotype and allele distributions, patients’ clinical status, and various risk factors for NTG. Results There was a significant difference between the patients with NTG and HTG and the controls (p = 0.035, p = 0.008) regarding the genotype of the C1222T and C70G polymorphism. Plasma concentrations of ET did not differ between the NTG and HTG groups, and no significant correlation with intraocular pressure (IOP), best-corrected visual acuity (BCVA), and the cup to disc ratio (c/d ratio) was seen in patients with NTG. Plasma endothelin levels showed a noticeably positive correlation with age in the NTG group (R = 0.249, p = 0.042). Higher endothelin levels corresponded to more advanced visual field damage. No statistical difference was observed between variant genotypes of K198N and the ET-1 plasma concentration in patients with NTG, whereas a slightly higher ET level was observed in the patients with HTG with the GT genotype in comparison to those with the GG genotype (p = 0.001). The C1222T polymorphism significantly affected the plasma ET level in patients with NTG. The TT genotype carriers had the highest ET level, and the CC genotype carriers the lowest (p = 0.034). The AA variant genotype of the G231A polymorphism exhibited the highest

  13. Role of Endothelin-1/Endothelin-A receptor-mediated signaling pathway in the aortic arch patterning in mice.

    PubMed Central

    Yanagisawa, H.; Hammer, R. E.; Richardson, J. A.; Williams, S. C.; Clouthier, D. E.; Yanagisawa, M.

    1998-01-01

    The intercellular signaling mediated by endothelins and their G protein-coupled receptors has recently been shown to be essential for the normal embryonic development of subsets of neural crest cell derivatives. Endothelin-1 (ET-1) is proteolytically generated from its inactive precursor by endothelin-converting enzyme-1 (ECE-1) and acts on the endothelin-A (ETA) receptor. Genetic disruption of this ET-1/ECE-1/ETA pathway results in defects in branchial arch- derived craniofacial tissues, as well as defects in cardiac outflow and great vessel structures, which are derived from cephalic (cardiac) neural crest. In this study, in situ hybridization of ETA-/- and ECE-1(-)/- embryos with a cardiac neural crest marker, cellular retinoic acid-binding protein-1, shows that the migration of neural crest cells from the neural tube to cardiac outflow tract is not affected in these embryos. Immunostaining of an endothelial marker, platelet endothelial cell adhesion molecule CD-31, shows that the initial formation of the branchial arch arteries is not disturbed in ETA-/- or ECE-1(-)/- embryos. To visualize the subsequent patterning of arch vessels in detail, we generated ETA-/- or ECE-1(-)/- embryos that expressed an SM22alpha-lacZ marker transgene in arterial smooth muscle cells. Wholemount X-gal staining of these mutant embryos reveals that the abnormal regression and persistence of specific arch arteries results in disturbance of asymmetrical remodeling of the arch arteries. These defects include abnormal regression of arch arteries 4 and 6, enlargement of arch artery 3, and abnormal persistence of the bilateral ductus caroticus and right dorsal aorta. These abnormalities eventually lead to various types of great vessel malformations highly similar to those seen in neural crest-ablated chick embryos and human congenital cardiac defects. This study demonstrates that ET-1/ETA-mediated signaling plays an essential role in a complex process of aortic arch patterning by affecting

  14. miR-30a inhibits endothelin A receptor and chemoresistance in ovarian carcinoma

    PubMed Central

    Rosanò, Laura; Tocci, Piera; Semprucci, Elisa; Di Castro, Valeriana; Caprara, Valentina; Ferrandina, Gabriella; Sacconi, Andrea; Blandino, Giovanni; Bagnato, Anna

    2016-01-01

    Drug resistance remains the major clinical barrier to successful treatment in epithelial ovarian carcinoma (EOC) patients, and the evidence of microRNA involvement in drug resistance has been recently emerging. Endothelin-1 (ET-1)/ETA receptor (ETAR) axis is aberrantly activated in chemoresistant EOC cells and elicits pleiotropic effects promoting epithelial-to-mesenchymal transition (EMT) and the acquisition of chemoresistance. However, the relationship between ETAR and miRNA is still unknown. Hence, in this study we evaluated whether dysregulation of miRNA might enhance ETAR expression in sensitive and resistant EOC cells. Based on bioinformatic tools, we selected putative miRNA able to recognize the 3′UTR of ETAR. An inverse correlation was observed between the expression levels of miR-30a and ETAR in both EOC cell lines and tumor samples. miR-30a was found to specifically bind to the 3′UTR of ETAR mRNA, indicating that ETAR is a direct target of miR-30a. Overexpression of miR-30a decreased Akt and mitogen activated protein kinase signaling pathway activation, cell proliferation, invasion, plasticity, EMT marker levels, and vascular endothelial growth factor release. Interestingly, ectopic expression of miR-30a re-sensitized platinum-resistant EOC cells to cisplatinum-induced apoptosis. Consistently, resistant EOC xenografts overexpressing miR-30a resulted in significantly less tumor growth than controls. Together our study provides a new perspective on the regulatory mechanism of ETAR gene. Interestingly, our findings highlight that blockade of ETAR regulatory axis is the mechanism underlying the tumor suppressor function of miR-30a in chemoresistant EOC cells. PMID:26675258

  15. Selective endothelin receptor blockade in resistant hypertension: results of the DORADO trial.

    PubMed

    Grassi, Guido

    2011-01-01

    Effective treatment of resistant hypertension still remains an unmet goal of antihypertensive drug treatment. The DORADO trial recently evaluated the efficacy and safety profile of the selective endothelin receptor blocker darusentan in almost 400 hypertensive patients treated with more than four antihypertensive drugs (including a diuretic) but without effective blood pressure control. The trial results show that > 50% of patients treated with the drug exhibit clinical blood pressure < 140/90 mmHg and well-controlled ambulatory blood pressure values. Darusentan, however, was associated with a high incidence of peripheral edema and fluid retention, a side effect that may reduce the safety profile of the drug and its tolerability. Although these data are promising, the drug requires further evaluation, with particularly regard to the long term.

  16. Role of endothelin-A receptors in optic nerve head red cell flux regulation during isometric exercise in healthy humans.

    PubMed

    Boltz, Agnes; Schmidl, Doreen; Werkmeister, René M; Lasta, Michael; Kaya, Semira; Palkovits, Stefan; Told, Reinhard; Frantal, Sophie; Garhöfer, Gerhard; Schmetterer, Leopold

    2013-01-01

    Endothelin-1 (ET-1) is an important regulator of vascular tone in the eye. It appears to play a role in ocular disease because of its strong vasoconstrictor action, its role in intraocular pressure homeostasis, and its neurotoxic potential. We have previously shown that ET-1 is involved in choroidal red cell flux (RCF) regulation during isometric exercise in healthy humans. In the present study we hypothesized that ET-1 also plays a role in optic nerve head (ONH) RCF regulation during isometric exercise. To test this hypothesis, we performed a randomized, double-masked, placebo-controlled, two-way crossover study in 15 healthy volunteers. Subjects were randomized to receive intravenous infusions of the specific endothelin type A receptor antagonist BQ-123 and placebo on two different study days. During these infusion periods, subjects performed squatting for 6 min to increase ocular perfusion pressure (OPP). ONH RCF was assessed with laser-Doppler flowmetry, and OPP was calculated from mean arterial pressure and intraocular pressure. BQ-123 did not change OPP or ONH RCF at baseline. The relative increase in OPP during isometric exercise was comparable between both groups (between 84 and 88%, P = 0.76 between groups; P < 0.001 vs. baseline). Isometric exercise increased ONH RCF during placebo and BQ-123, but the increase was more pronounced when the endothelin type-A receptor antagonist was administered (placebo, 27.3 ± 5.4%; and BQ-123, 39.2 ± 4.4%; P = 0.007 between groups). The present data indicate that ET-1 regulates red cell flux in the ONH beyond the autoregulatory range.

  17. Antifibrotic effects of ambrisentan, an endothelin-A receptor antagonist, in a non-alcoholic steatohepatitis mouse model

    PubMed Central

    Okamoto, Toshiaki; Koda, Masahiko; Miyoshi, Kennichi; Onoyama, Takumi; Kishina, Manabu; Matono, Tomomitsu; Sugihara, Takaaki; Hosho, Keiko; Okano, Junichi; Isomoto, Hajime; Murawaki, Yoshikazu

    2016-01-01

    AIM To examine the effects of the endothelin type A receptor antagonist ambrisentan on hepatic steatosis and fibrosis in a steatohepatitis mouse model. METHODS Fatty liver shionogi (FLS) FLS-ob/ob mice (male, 12 wk old) received ambrisentan (2.5 mg/kg orally per day; n = 8) or water as a control (n = 5) for 4 wk. Factors were compared between the two groups, including steatosis, fibrosis, inflammation, and endothelin-related gene expression in the liver. RESULTS In the ambrisentan group, hepatic hydroxyproline content was significantly lower than in the control group (18.0 μg/g ± 6.1 μg/g vs 33.9 μg/g ± 13.5 μg/g liver, respectively, P = 0.014). Hepatic fibrosis estimated by Sirius red staining and areas positive for α-smooth muscle actin, indicative of activated hepatic stellate cells, were also significantly lower in the ambrisentan group (0.46% ± 0.18% vs 1.11% ± 0.28%, respectively, P = 0.0003; and 0.12% ± 0.08% vs 0.25% ± 0.11%, respectively, P = 0.047). Moreover, hepatic RNA expression levels of procollagen-1 and tissue inhibitor of metalloproteinase-1 (TIMP-1) were significantly lower by 60% and 45%, respectively, in the ambrisentan group. Inflammation, steatosis, and endothelin-related mRNA expression in the liver were not significantly different between the groups. CONCLUSION Ambrisentan attenuated the progression of hepatic fibrosis by inhibiting hepatic stellate cell activation and reducing procollagen-1 and TIMP-1 gene expression. Ambrisentan did not affect inflammation or steatosis. PMID:27574547

  18. The Endothelin Type A Receptor as a Potential Therapeutic Target in Preeclampsia

    PubMed Central

    Bakrania, Bhavisha; Duncan, Jeremy; Warrington, Junie P.; Granger, Joey P.

    2017-01-01

    Preeclampsia (PE) is a disorder of pregnancy typically characterized by new onset hypertension after gestational week 20 and proteinuria. Although PE is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disease remain unclear and treatment options are limited. However, there is increasing evidence to suggest that endothelin-1 (ET-1) plays a critical role in the pathophysiology of PE. Multiple studies report that ET-1 is increased in PE and some studies report a positive correlation between ET-1 and the severity of symptoms. A number of experimental models of PE are also associated with elevated tissue levels of prepro ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 infusion, Tumor necrosis factor (TNF) -α infusion, and Angiotensin II type 1 receptor autoantibody (AT1-AA) infusion) have proven to be susceptible to Endothelin Type A (ETA) receptor antagonism. While the results are promising, further work is needed to determine whether ET antagonists could provide an effective therapy for the management of preeclampsia. PMID:28264495

  19. Endothelin Receptor Blockade Ameliorates Vascular Fragility in Endothelial Cell–Specific Fli-1–Knockout Mice by Increasing Fli-1 DNA Binding Ability

    PubMed Central

    Akamata, Kaname; Asano, Yoshihide; Yamashita, Takashi; Noda, Shinji; Taniguchi, Takashi; Takahashi, Takehiro; Ichimura, Yohei; Toyama, Tetsuo; Trojanowska, Maria; Sato, Shinichi

    2016-01-01

    Objective It is generally accepted that blockade of endothelin receptors has potentially beneficial effects on vasculopathy associated with systemic sclerosis (SSc). The aim of this study was to clarify the molecular mechanism underlying these effects using endothelial cell–specific Fli-1–knockout (Fli-1 ECKO) mice, an animal model of SSc vasculopathy. Methods Levels of messenger RNA for target genes and the expression and phosphorylation levels of target proteins were determined in human and murine dermal microvascular endothelial cells by real-time quantitative reverse transcription–polymerase chain reaction and immunoblotting, respectively. The binding of Fli-1 to the target gene promoters was evaluated using chromatin immunoprecipitation. Expression levels of Fli-1 and α-smooth muscle actin in murine skin were evaluated using immunohistochemistry. Vascular structure and permeability were evaluated in mice injected with fluorescein isothiocyanate–dextran and Evans blue dye, respectively. Results In human dermal microvascular endothelial cells, endothelin 1 induced phosphorylation of Fli-1 at Thr312 through the sequential activation of c-Abl and protein kinase Cδ, leading to a decrease in Fli-1 protein levels as well as a decrease in binding of Fli-1 to the target gene promoters, whereas bosentan treatment reversed those effects. In Fli-1 ECKO mice, 4 weeks of treatment with bosentan increased endothelial Fli-1 expression, resulting in vascular stabilization and the restoration of impaired leaky vessels. Conclusion The vascular fragility of Fli-1 ECKO mice was improved by bosentan through the normalization of Fli-1 protein levels and activity in endothelial cells, which may explain, in part, the mechanism underlying the beneficial effects of endothelin receptor blockade on SSc vasculopathy. PMID:25707716

  20. Remodeling of striatal NMDA receptors by chronic A(2A) receptor blockade in Huntington's disease mice.

    PubMed

    Martire, Alberto; Ferrante, Antonella; Potenza, Rosa Luisa; Armida, Monica; Ferretti, Roberta; Pézzola, Antonella; Domenici, Maria Rosaria; Popoli, Patrizia

    2010-01-01

    Excitotoxicity plays a major role in the pathogenesis of Huntington disease (HD), a fatal neurodegenerative disorder. Adenosine A(2A) receptors (A(2A)Rs) modulate excitotoxicity and have been suggested to play a pathogenetic role in HD. The main aim of this study was to evaluate the effect of A(2A)R blockade on the expression and functions of NMDA receptors in the striatum of HD mice (R6/2). We found that 3 weeks' treatment with SCH 58261 (0.01 mg/kg/day i.p. from the 8th week of age) modified NR1 and NR2A/NR2B expression in the striatum of R6/2 (Western blotting) while had no effect on NMDA-induced toxicity in corticostriatal slices (electrophysiological experiments). In conclusion, in vivo A(2A)R blockade induced a remodeling of NMDA receptors in the striatum of HD mice. Even though the functional relevance of the above effect remains to be fully elucidated, these results add further evidence to the modulatory role of A(2A)Rs in HD.

  1. Effect of clazosentan, a selective endothelin A receptor antagonist, and tezosentan, a dual endothelin A/B antagonist, on pulsatile shear stress induced constriction of the iliac in the anaesthetized pig.

    PubMed

    Ruane-O'Hora, Therese; Rae, Mark George; Markos, Farouk

    2011-08-01

    1. The effects of changes in mean and pulsatile shear stress on the diameter of the iliac of the anaesthetized pig were investigated in the presence of clazosentan and tezosentan. 2. A total of 17 pigs were used. Mean shear stress was increased by infusing acetylcholine downstream (2-20 μg/min) through the deep femoral artery. Pulsatile shear stress was enhanced first by injecting varying volumes (1-10 mL) of calcium gluconate (stock 10 mg/mL) directly into the left ventricle. Second, by electrical stimulation of the left sympathetic nerves to the heart (1-16 Hz, 4 min duration, supramaximal voltage). 3. An increase in mean shear stress induced a vasodilation that was not altered significantly by the selective endothelin A antagonist clazosentan (10 mg/kg i.v.). Similarly, the vasoconstriction induced by an increase in pulsatile shear stress brought about by either calcium gluconate injections or left sympathetic nerve stimulation was unaffected by clazosentan. However, tezosentan (10 mg/kg i.v.), significantly attenuated the vasoconstriction induced by an increase in pulsatile shear stress. 4. In conclusion, an increase in pulsatile shear stress causes vasoconstriction of the pig iliac artery, which is attenuated by dual endothelin receptor antagonism, but not by specific endothelin A blockade.

  2. Minimally Modified LDL Upregulates Endothelin Type A Receptors in Rat Coronary Arterial Smooth Muscle Cells

    PubMed Central

    Li, Jie; Cao, Lei; Xu, Cang-Bao; Wang, Jun-Jie

    2013-01-01

    Minimally modified low-density lipoprotein (mmLDL) is a risk factor for cardiovascular disease. The present study investigated the effects of mmLDL on the expression of endothelin type A (ETA) receptors in coronary arteries. Rat coronary arteries were organ-cultured for 24 h. The contractile responses were recorded using a myographic system. ETA receptor mRNA and protein expressions were determined using real-time PCR and western blotting, respectively. The results showed that organ-culturing in the presence of mmLDL enhanced the arterial contractility mediated by the ETA receptor in a concentration-dependent and time-dependent manner. Culturing with mmLDL (10 μg/mL) for 24 h shifted the concentration-contractile curves toward the left significantly with increased Emax of 228% ± 20% from control of 100% ± 10% and significantly increased ETA receptor mRNA and protein levels. Inhibition of the protein kinase C, extracellular signal-related kinases 1 and 2 (ERK1/2), or NF-κB activities significantly attenuated the effects of mmLDL. The c-Jun N-terminal kinase inhibitor or the p38 pathway inhibitor, however, had no such effects. The results indicate that mmLDL upregulates the ETA receptors in rat coronary arterial smooth muscle cells mainly via activating protein kinase C, ERK1/2, and the downstream transcriptional factor, NF-κB. PMID:23861561

  3. Long-Term Endothelin-A Receptor Antagonism Provides Robust Renal Protection in Humanized Sickle Cell Disease Mice.

    PubMed

    Kasztan, Malgorzata; Fox, Brandon M; Speed, Joshua S; De Miguel, Carmen; Gohar, Eman Y; Townes, Tim M; Kutlar, Abdullah; Pollock, Jennifer S; Pollock, David M

    2017-03-27

    Sickle cell disease (SCD)-associated nephropathy is a major source of morbidity and mortality in patients because of the lack of efficacious treatments targeting renal manifestations of the disease. Here, we describe a long-term treatment strategy with the selective endothelin-A receptor (ETA) antagonist, ambrisentan, designed to interfere with the development of nephropathy in a humanized mouse model of SCD. Ambrisentan preserved GFR at the level of nondisease controls and prevented the development of proteinuria, albuminuria, and nephrinuria. Microscopy studies demonstrated prevention of podocyte loss and structural alterations, the absence of vascular congestion, and attenuation of glomerulosclerosis in treated mice. Studies in isolated glomeruli showed that treatment reduced inflammation and oxidative stress. At the level of renal tubules, ambrisentan treatment prevented the increased excretion of urinary tubular injury biomarkers. Additionally, the treatment strategy prevented tubular brush border loss, diminished tubular iron deposition, blocked the development of interstitial fibrosis, and prevented immune cell infiltration. Furthermore, the prevention of albuminuria in treated mice was associated with preservation of cortical megalin expression. In a separate series of identical experiments, combined ETA and ETB receptor antagonism provided only some of the protection observed with ambrisentan, highlighting the importance of exclusively targeting the ETA receptor in SCD. Our results demonstrate that ambrisentan treatment provides robust protection from diverse renal pathologies in SCD mice, and suggest that long-term ETA receptor antagonism may provide a strategy for the prevention of renal complications of SCD.

  4. Endothelin ETA receptor antagonism in cardiovascular disease.

    PubMed

    Nasser, Suzanne A; El-Mas, Mahmoud M

    2014-08-15

    Since the discovery of the endothelin system in 1988, it has been implicated in numerous physiological and pathological phenomena. In the cardiovascular system, endothelin-1 (ET-1) acts through intracellular pathways of two endothelin receptors (ETA and ETB) located mainly on smooth muscle and endothelial cells to regulate vascular tone and provoke mitogenic and proinflammatory reactions. The endothelin ETA receptor is believed to play a pivotal role in the pathogenesis of several cardiovascular disease including systemic hypertension, pulmonary arterial hypertension (PAH), dilated cardiomyopathy, and diabetic microvascular dysfunction. Growing evidence from recent experimental and clinical studies indicates that the blockade of endothelin receptors, particularly the ETA subtype, grasps promise in the treatment of major cardiovascular pathologies. The simultaneous blockade of endothelin ETB receptors might not be advantageous, leading possibly to vasoconstriction and salt and water retentions. This review summarizes the role of ET-1 in cardiovascular modulation and the therapeutic potential of endothelin receptor antagonism.

  5. Endothelin B Receptor, a New Target in Cancer Immune Therapy

    PubMed Central

    Kandalaft, Lana E.; Facciabene, Andrea; Buckanovich, Ron J.; Coukos, George

    2010-01-01

    The endothelins and their G protein-coupled receptors A and B have been implicated innumerous diseases and have recently emerged as pivotal players in a variety of malignancies. Tumors over-express the endothelin 1 (ET-1) ligand and the endothelin-A-receptor (ETAR). Their interaction induces tumor growth and metastasis by promoting tumor cell survival and proliferation, angiogenesis, and tissue remodeling. On the basis of results from xenograft models, drug development efforts have focused on antagonizing the autocrine-paracrine effects mediated by ET-1/ETAR. In this review, we discuss a novel role of the endothelin-B-receptor (ETBR) in tumorigenesis and the effect of its blockade during cancer immune therapy. We highlight key characteristics of the B receptor such as its specific overexpression in the tumor compartment; and specifically, in the tumor endothelium, where its activation by ET-1 suppresses T-cell adhesion and homing to tumors. We also review our recent findings on the effects of ETBR-specific blockade in increasing T-cell homing to tumors and enhancing the efficacy of otherwise ineffective immunotherapy. PMID:19567593

  6. Adenosine A2A receptor blockade differentially influences excitotoxic mechanisms at pre- and postsynaptic sites in the rat striatum.

    PubMed

    Tebano, Maria Teresa; Pintor, Annita; Frank, Claudio; Domenici, Maria Rosaria; Martire, Alberto; Pepponi, Rita; Potenza, Rosa Luisa; Grieco, Rosa; Popoli, Patrizia

    2004-07-01

    Adenosine A(2A) receptor antagonists are being regarded as potential neuroprotective drugs, although the mechanisms underlying their effects need to be better studied. The aim of this work was to investigate further the mechanism of the neuroprotective action of A(2A) receptor antagonists in models of pre- and postsynaptic excitotoxicity. In microdialysis studies, the intrastriatal perfusion of the A(2A) receptor antagonist ZM 241385 (5 and 50 nM) significantly reduced, in an inversely dose-dependent way, the raise in glutamate outflow induced by 5 mM quinolinic acid (QA). In rat corticostriatal slices, ZM 241385 (30-100 nM) significantly reduced 4-aminopyridine (4-AP)-induced paired-pulse inhibition (PPI; an index of neurotransmitter release), whereas it worsened the depression of field potential amplitude elicited by N-methyl-D-aspartate (NMDA; 12.5 and 50 microM). The A(2A) antagonist SCH 58261 (30 nM) mimicked the effects of ZM 241385, whereas the A(2A) agonist CGS 21680 (100 nM) showed a protective influence toward 50 microM NMDA. In rat striatal neurons, 50 nM ZM 241385 did not affect the increase in [Ca(2+)](i) or the release of lactate dehydrogenase (LDH) induced by 100 and 300 microM NMDA, respectively. The ability of ZM 241385 to prevent QA-induced glutamate outflow and 4-AP-induced effects confirms that A(2A) receptor antagonists have inhibitory effects on neurotransmitter release, whereas the results obtained toward NMDA-induced effects suggest that A(2A) receptor blockade does not reduce, or even amplifies, excitotoxic mechanisms due to direct NMDA receptor stimulation. This indicates that the neuroprotective potential of A(2A) antagonists may be evident mainly in models of neurodegeneration in which presynaptic mechanisms play a major role.

  7. Adenosine A2A Receptor Blockade Prevents Rotenone-Induced Motor Impairment in a Rat Model of Parkinsonism

    PubMed Central

    Fathalla, Ahmed M.; Soliman, Amira M.; Ali, Mohamed H.; Moustafa, Ahmed A.

    2016-01-01

    Pharmacological studies implicate the blockade of adenosine receptorsas an effective strategy for reducing Parkinson’s disease (PD) symptoms. The objective of this study is to elucidate the possible protective effects of ZM241385 and 8-cyclopentyl-1, 3-dipropylxanthine, two selective A2A and A1 receptor antagonists, on a rotenone rat model of PD. Rats were split into four groups: vehicle control (1 ml/kg/48 h), rotenone (1.5 mg/kg/48 h, s.c.), ZM241385 (3.3 mg/kg/day, i.p) and 8-cyclopentyl-1, 3-dipropylxanthine (5 mg/kg/day, i.p). After that, animals were subjected to behavioral (stride length and grid walking) and biochemical (measuring concentration of dopamine levels using high performance liquid chromatography, HPLC). In the rotenone group, rats displayed a reduced motor activity and disturbed movement coordination in the behavioral tests and a decreased dopamine concentration as foundby HPLC. The effect of rotenone was partially prevented in the ZM241385 group, but not with 8-cyclopentyl-1,3-dipropylxanthine administration. The administration of ZM241385 improved motor function and movement coordination (partial increase of stride length and partial decrease in the number of foot slips) and an increase in dopamine concentration in the rotenone-injected rats. However, the 8-cyclopentyl-1,3-dipropylxanthine and rotenone groups were not significantly different. These results indicate that selective A2A receptor blockade by ZM241385, but not A1 receptor blockadeby 8-cyclopentyl-1,3-dipropylxanthine, may treat PD motor symptoms. This reinforces the potential use of A2A receptor antagonists as a treatment strategy for PD patients. PMID:26973484

  8. Selective endothelinA receptor antagonism with sitaxsentan for pulmonary arterial hypertension associated with connective tissue disease

    PubMed Central

    Girgis, Reda E; Frost, Adaani E; Hill, Nicholas S; Horn, Evelyn M; Langleben, David; McLaughlin, Vallerie V; Oudiz, Ronald J; Robbins, Ivan M; Seibold, James R; Shapiro, Shelley; Tapson, Victor F; Barst, Robyn J

    2007-01-01

    Introduction Endothelin receptor antagonism has become an important component in the treatment of pulmonary arterial hypertension (PAH) associated with connective tissue disease (CTD). The purpose of this study was to analyse the safety and effectiveness of sitaxsentan, a selective antagonist of the ETA receptor, in a cohort of patients with PAH and CTD. Short‐term clinical and haemodynamic effects and longer‐term follow‐up data are presented. Methods A post hoc subgroup analysis was performed on 42 patients who had PAH associated with CTD, out of a group of 178 patients enrolled in a 12‐week, double‐blind, randomised clinical trial of sitaxsentan versus placebo. Data from 33 patients assigned to sitaxsentan 100 mg or 300 mg daily were pooled and compared with nine placebo‐treated patients. There were 41 patients entered into the blinded extension study, in which all patients received either 100 mg or 300 mg sitaxsentan once daily. Results Patients treated with sitaxsentan had a mean (SD) increase in 6 minute walk distance of 20 (5) m from baseline to week 12 (p = 0.037), whereas the placebo group had a decrease of 38 (84) m, resulting in a placebo‐subtracted treatment effect of 58 m (p = 0.027). Parallel improvements in quality of life and haemodynamics were also observed. No patient discontinued their drug during the 12‐week trial. In the blinded extension study (median treatment duration 26 weeks), more patients were in functional class I–II than in III–IV (p<0.001) at the end of the study compared with the start of active therapy. Elevation of hepatic transaminase levels occurred in two patients. Conclusions Sitaxsentan appears to be efficacious in patients with PAH associated with CTD. PMID:17472992

  9. Overexpression of Endothelin-A-receptor in breast cancer: regulation by estradiol and cobalt-chloride induced hypoxia.

    PubMed

    Wülfing, Pia; Götte, Martin; Sonntag, Barbara; Kersting, Christian; Schmidt, Hartmut; Wülfing, Christian; Buerger, Horst; Greb, Robert; Böcker, Werner; Kiesel, Ludwig

    2005-04-01

    Previous studies have demonstrated the potential significance of Endothelin (ET)-1 and its receptors, ETAR and ETBR, in the development and progression of breast cancer. The objective of this study was to assess the expression levels and potential regulation of the "ET axis" in human non-neoplastic and neoplastic breast tissue as well as in various human breast cancer cell lines. Expression of ET-1, ETAR and ETBR was evaluated in 31 neoplastic and 7 non-neoplastic breast tissue samples and in six human breast cancer cell lines using conventional and quantitative real-time RT-PCR, Western blotting and immunohistochemistry. The effects of 17beta-estradiol (E2) and cobalt-chloride (CoCl2) treatment on ET-1, ETAR and ETBR expression were studied in vitro. ETAR mRNA expression levels were found to be statistically significantly higher in breast cancer specimens than in non-neoplastic breast tissue (p<0.001). For ET-1 and ETBR mRNA expression, no significant difference was observed between the two groups. All cell lines exhibited expression of ET-1 and ETAR mRNA, whereas none showed significant ETBR mRNA expression. We observed a strong and reproducible induction of ETAR mRNA and protein expression by E2 and CoCl2 in MDA-MB-468 and BT-474 cells and in MDA-MB-453 and SK-BR-3 cells with a maximum increase after 8 and 16 h of treatment, respectively, while MCF-7 and HBL-100 cells showed a constitutive expression pattern. The present data suggest a novel mechanism in the regulation of ETAR expression in breast cancer. Based on these findings, a combination of ETAR-antagonists with adjuvant endocrine treatment seems to be a reasonable therapeutic strategy.

  10. Endothelin-1 induces proliferation of human lung fibroblasts and IL-11 secretion through an ET(A) receptor-dependent activation of MAP kinases.

    PubMed

    Gallelli, Luca; Pelaia, Girolamo; D'Agostino, Bruno; Cuda, Giovanni; Vatrella, Alessandro; Fratto, Donatella; Gioffrè, Vincenza; Galderisi, Umberto; De Nardo, Marilisa; Mastruzzo, Claudio; Salinaro, Elisa Trovato; Maniscalco, Mauro; Sofia, Matteo; Crimi, Nunzio; Rossi, Francesco; Caputi, Mario; Costanzo, Francesco S; Maselli, Rosario; Marsico, Serafino A; Vancheri, Carlo

    2005-11-01

    Endothelin-1 (ET-1) is implicated in the fibrotic responses characterizing interstitial lung diseases, as well as in the airway remodeling process occurring in asthma. Within such a context, the aim of our study was to investigate, in primary cultures of normal human lung fibroblasts (NHLFs), the ET-1 receptor subtypes, and the intracellular signal transduction pathways involved in the proliferative effects of this peptide. Therefore, cells were exposed to ET-1 in the presence or absence of an overnight pre-treatment with either ET(A) or ET(B) selective receptor antagonists. After cell lysis, immunoblotting was performed using monoclonal antibodies against the phosphorylated, active forms of mitogen-activated protein kinases (MAPK). ET-1 induced a significant increase in MAPK phosphorylation pattern, and also stimulated fibroblast proliferation and IL-6/IL-11 release into cell culture supernatants. All these effects were inhibited by the selective ET(A) antagonist BQ-123, but not by the specific ET(B) antagonist BQ-788. The stimulatory influence of ET-1 on IL-11, but not on IL-6 secretion, was prevented by MAPK inhibitors. Therefore, such results suggest that in human lung fibroblasts ET-1 exerts a profibrogenic action via an ET(A) receptor-dependent, MAPK-mediated induction of IL-11 release and cell proliferation.

  11. Specific endothelin ET(A) receptor antagonism does not modulate insulin-induced hemodynamic effects in the human kidney, eye, or forearm.

    PubMed

    Rab, Anna; Dallinger, Susanne; Polak, Kaija; Pleiner, Johannes; Polska, Elzbieta; Wolzt, Michael; Schmetterer, Leopold

    2004-05-01

    There is evidence that hyperinsulinemia may stimulate endothelin-1 (ET-1) generation or release, which may affect diabetic vascular complications. BQ-123, a specific ET(A) receptor antagonist, was used to investigate if insulin-induced vascular effects are influenced by an acute ET-1 release. Two randomized, placebo-controlled, double-blind, cross-over studies were performed. In protocol 1, 12 healthy subjects received, on separate study days, infusions of BQ-123 (60 microg/min for 30 min) during placebo clamp conditions, BQ-123 during euglycemic hyperinsulinemia (3 mU/kg/min for 390 min), or placebo during euglycemic hyperinsulinemia. Fundus pulsation amplitude (FPA) was measured to assess pulsatile choroidal blood flow, and mean flow velocity (MFV) of the ophtalmic artery was measured by color Doppler imaging. In protocol 2, eight healthy subjects received, on separate study days, intra-arterial infusions of BQ-123 (32 microg/min for 120 min) during placebo or insulin clamp. Forearm blood flow was measured with bilateral plethysmography, expressing the ratio of responses in the intervention arm and in the control arm. Insulin alone increased FPA (+10%, p < 0.001) and forearm blood flow (+19%). BQ-123 increased FPA, MFV, and forearm blood flow ratio in the absence and presence of exogenous insulin, but this effect was not different between normo- and hyperinsulinemic conditions. ET-1 plasma concentrations were not affected by insulin. In conclusion, these data do not support the concept that hyperinsulinemia increases ET-1 generation in healthy subjects. Our results, however, cannot necessarily be extrapolated to diabetic and obese subjects.

  12. Differential effects of presynaptic versus postsynaptic adenosine A2A receptor blockade on Δ9-tetrahydrocannabinol (THC) self-administration in squirrel monkeys.

    PubMed

    Justinová, Zuzana; Redhi, Godfrey H; Goldberg, Steven R; Ferré, Sergi

    2014-05-07

    Different doses of an adenosine A2A receptor antagonist MSX-3 [3,7-dihydro-8-[(1E)-2-(3-ethoxyphenyl)ethenyl]-7 methyl-3-[3-(phosphooxy)propyl-1-(2 propynil)-1H-purine-2,6-dione] were found previously to either decrease or increase self-administration of cannabinoids delta-9-tetrahydrocannabinol (THC) or anandamide in squirrel monkeys. It was hypothesized that the decrease observed with a relatively low dose of MSX-3 was related to blockade of striatal presynaptic A2A receptors that modulate glutamatergic neurotransmission, whereas the increase observed with a higher dose was related to blockade of postsynaptic A2A receptors localized in striatopallidal neurons. This hypothesis was confirmed in the present study by testing the effects of the preferential presynaptic and postsynaptic A2A receptor antagonists SCH-442416 [2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine] and KW-6002 [(E)-1, 3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione], respectively, in squirrel monkeys trained to intravenously self-administer THC. SCH-442416 produced a significant shift to the right of the THC self-administration dose-response curves, consistent with antagonism of the reinforcing effects of THC. Conversely, KW-6002 produced a significant shift to the left, consistent with potentiation of the reinforcing effects of THC. These results show that selectively blocking presynaptic A2A receptors could provide a new pharmacological approach to the treatment of marijuana dependence and underscore corticostriatal glutamatergic neurotransmission as a possible main mechanism involved in the rewarding effects of THC.

  13. Blockade of Serotonin 5-HT2A Receptors Suppresses Behavioral Sensitization and Naloxone-Precipitated Withdrawal Symptoms in Morphine-Treated Mice

    PubMed Central

    Pang, Gang; Wu, Xian; Tao, Xinrong; Mao, Ruoying; Liu, Xueke; Zhang, Yong-Mei; Li, Guangwu; Stackman, Robert W.; Dong, Liuyi; Zhang, Gongliang

    2016-01-01

    The increasing prescription of opioids is fueling an epidemic of addiction and overdose deaths. Morphine is a highly addictive drug characterized by a high relapse rate – even after a long period of abstinence. Serotonin (5-HT) neurotransmission participates in the development of morphine dependence, as well as the expression of morphine withdrawal. In this study, we examined the effect of blockade of 5-HT2A receptors (5-HT2ARs) on morphine-induced behavioral sensitization and withdrawal in male mice. 5-HT2AR antagonist MDL 11,939 (0.5 mg/kg, i.p.) suppressed acute morphine (5.0 mg/kg, s.c.)-induced increase in locomotor activity. Mice received morphine (10 mg/kg, s.c.) twice a day for 3 days and then drug treatment was suspended for 5 days. On day 9, a challenge dose of morphine (10 mg/kg) was administered to induce the expression of behavioral sensitization. MDL 11,939 (0.5 mg/kg, i.p.) pretreatment suppressed the expression of morphine-induced behavioral sensitization. Another cohort of mice received increasing doses of morphine over a 7-day period to induce morphine-dependence. MDL 11,939 (0.5 mg/kg, i.p.) prevented naloxone-precipitated withdrawal in morphine-dependent mice on day 7. Moreover, chronic morphine treatment increased 5-HT2AR protein level and decreased the phosphorylation of extracellular signal-regulated kinases in the prefrontal cortex. Together, these results by the first time demonstrate that 5-HT2ARs modulate opioid dependence and blockade of 5-HT2AR may represent a novel strategy for the treatment of morphine use disorders. Highlights (i) Blockade of 5-HT2A receptors suppresses the expression of morphine-induced behavioral sensitization. (ii) Blockade of 5-HT2A receptors suppresses naloxone-precipitated withdrawal in morphine-treated mice. (iii) Chronic morphine exposure induces an increase in 5-HT2A receptor protein level and a decrease in ERK protein phosphorylation in prefrontal cortex. PMID:28082900

  14. The effect of endothelin A and B receptor blockade on cutaneous vascular and sweating responses in young men during and following exercise in the heat.

    PubMed

    Fujii, Naoto; Singh, Maya S; Halili, Lyra; Louie, Jeffrey C; Kenny, Glen P

    2016-12-01

    During exercise, cutaneous vasodilation and sweating responses occur, whereas these responses rapidly decrease during postexercise recovery. We hypothesized that the activation of endothelin A (ETA) receptors, but not endothelin B (ETB) receptors, attenuate cutaneous vasodilation during high-intensity exercise and contribute to the subsequent postexercise suppression of cutaneous vasodilation. We also hypothesized that both receptors increase sweating during and following high-intensity exercise. Eleven men (24 ± 4 yr) performed an intermittent cycling protocol consisting of two 30-min bouts of moderate- (40% V̇o2peak) and high-intensity (75% V̇o2peak) exercise in the heat (35°C), each separated by a 20- and 40-min recovery period, respectively. Cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal microdialysis skin sites: 1) lactated Ringer (control), 2) 500 nM BQ123 (a selective ETA receptor blocker), 3) 300 nM BQ788 (a selective ETB receptor blocker), or 4) a combination of BQ123 + BQ788. There were no between-site differences in CVC during each exercise bout (all P > 0.05); however, CVC following high-intensity exercise was greater at BQ123 (56 ± 9%max) and BQ123 + BQ788 (55 ± 14%max) sites relative to the control site (43 ± 12%max) (all P ≤ 0.05). Sweat rate did not differ between sites throughout the protocol (all P > 0.05). We show that neither ETA nor ETB receptors modulate cutaneous vasodilation and sweating responses during and following moderate- and high-intensity exercise in the heat, with the exception that ETA receptors may partly contribute to the suppression of cutaneous vasodilation following high-intensity exercise.

  15. GABA(A) receptor blockade in dorsomedial and ventromedial nuclei of the hypothalamus evokes panic-like elaborated defensive behaviour followed by innate fear-induced antinociception.

    PubMed

    Freitas, Renato Leonardo; Uribe-Mariño, Andrés; Castiblanco-Urbina, Maria Angélica; Elias-Filho, Daoud Hibraim; Coimbra, Norberto Cysne

    2009-12-11

    Dysfunction in the hypothalamic GABAergic system has been implicated in panic syndrome in humans. Furthermore, several studies have implicated the hypothalamus in the elaboration of pain modulation. Panic-prone states are able to be experimentally induced in laboratory animals to study this phenomenon. The aim of the present work was to investigate the involvement of medial hypothalamic nuclei in the organization of panic-like behaviour and the innate fear-induced oscillations of nociceptive thresholds. The blockade of GABA(A) receptors in the neuronal substrates of the ventromedial or dorsomedial hypothalamus was followed by elaborated defensive panic-like reactions. Moreover, innate fear-induced antinociception was consistently elicited after the escape behaviour. The escape responses organized by the dorsomedial and ventromedial hypothalamic nuclei were characteristically more elaborated, and a remarkable exploratory behaviour was recorded during GABA(A) receptor blockade in the medial hypothalamus. The motor characteristic of the elaborated defensive escape behaviour and the patterns of defensive alertness and defensive immobility induced by microinjection of the bicuculline either into the dorsomedial or into the ventromedial hypothalamus were very similar. This was followed by the same pattern of innate fear-induced antinociceptive response that lasted approximately 40 min after the elaborated defensive escape reaction in both cases. These findings suggest that dysfunction of the GABA-mediated neuronal system in the medial hypothalamus causes panic-like responses in laboratory animals, and that the elaborated escape behaviour organized in both dorsomedial and ventromedial hypothalamic nuclei are followed by significant innate-fear-induced antinociception. Our findings indicate that the GABA(A) receptor of dorsomedial and ventromedial hypothalamic nuclei are critically involved in the modulation of panic-like behaviour.

  16. Chronic and acute adenosine A2A receptor blockade prevents long-term episodic memory disruption caused by acute cannabinoid CB1 receptor activation.

    PubMed

    Mouro, Francisco M; Batalha, Vânia L; Ferreira, Diana G; Coelho, Joana E; Baqi, Younis; Müller, Christa E; Lopes, Luísa V; Ribeiro, Joaquim A; Sebastião, Ana M

    2017-05-01

    Cannabinoid-mediated memory impairment is a concern in cannabinoid-based therapies. Caffeine exacerbates cannabinoid CB1 receptor (CB1R)-induced memory deficits through an adenosine A1 receptor-mediated mechanism. We now evaluated how chronic or acute blockade of adenosine A2A receptors (A2ARs) affects long-term episodic memory deficits induced by a single injection of a selective CB1R agonist. Long-term episodic memory was assessed by the novel object recognition (NOR) test. Mice received an intraperitoneal (i.p.) injection of the CB1/CB2 receptor agonist WIN 55,212-2 (1 mg/kg) immediately after the NOR training, being tested for novelty recognition 24 h later. Anxiety levels were assessed by the Elevated Plus Maze test, immediately after the NOR. Mice were also tested for exploratory behaviour at the Open Field. For chronic A2AR blockade, KW-6002 (istradefylline) (3 mg/kg/day) was administered orally for 30 days; acute blockade of A2ARs was assessed by i.p. injection of SCH 58261 (1 mg/kg) administered either together with WIN 55,212-2 or only 30 min before the NOR test phase. The involvement of CB1Rs was assessed by using the CB1R antagonist, AM251 (3 mg/kg, i.p.). WIN 55,212-2 caused a disruption in NOR, an action absent in mice also receiving AM251, KW-6002 or SCH 58261 during the encoding/consolidation phase; SCH 58251 was ineffective if present during retrieval only. No effects were detected in the Elevated Plus maze or Open Field Test. The finding that CB1R-mediated memory disruption is prevented by antagonism of adenosine A2ARs, highlights a possibility to prevent cognitive side effects when therapeutic application of CB1R drugs is desired.

  17. Selective blockade of 5-HT2A receptors attenuates the increased temperature response in brown adipose tissue to restraint stress in rats.

    PubMed

    Ootsuka, Youichirou; Blessing, William W; Nalivaiko, Eugene

    2008-03-01

    Previous studies have demonstrated that 5-HT2A receptors may be involved in the central control of thermoregulation and of the cardiovascular system. Our aim was to test whether these receptors mediate thermogenic and tachycardiac responses induced by acute psychological stress. Three groups of adult male Hooded Wistar rats were instrumented with: (i) a thermistor in the interscapular area (for recording brown adipose tissue temperature) and an ultrasound Doppler probe (to record tail blood flow); (ii) temperature dataloggers to record core body temperature; (iii) ECG electrodes. On the day of the experiment, rats were subjected to a 30-min restraint stress preceded by s.c. injection of either vehicle or SR-46349B (a serotonin 2A receptor antagonist) at doses of 0.01, 0.1 and 1.0 mg/kg. The restraint stress caused a rise in brown adipose tissue temperature (from, mean +/- s.e.m., 36.6 +/- 0.2 to 38.0 +/- 0.2 degrees C), transient cutaneous vasoconstriction (tail blood flow decreased from 12 +/- 2 to 5 +/- 1 cm/s), increase in heart rate (from 303 +/- 15 to 453 +/- 15 bpm at the peak, then reduced to 393 +/- 12 bpm at the steady state), and defaecation (6 +/- 1 pellets per restraint session). The core body temperature was not affected by the restraint. Blockade of 5-HT2A receptors attenuated the increase in brown adipose tissue temperature and transient cutaneous vasoconstriction, but not tachycardia and defaecation elicited by restraint stress. These results indicate that psychological stress causes activation of 5-HT2A receptors in neural pathways that control thermogenesis in the brown adipose tissue and facilitate cutaneous vasoconstriction.

  18. 5-HT1A receptor blockade targeting the basolateral amygdala improved stress-induced impairment of memory consolidation and retrieval in rats.

    PubMed

    Sardari, M; Rezayof, A; Zarrindast, M-R

    2015-08-06

    The aim of the present study was to investigate the possible role of basolateral amygdala (BLA) 5-HT1A receptors in memory formation under stress. We also examined whether the blockade of these receptors is involved in stress-induced state-dependent memory. Adult male Wistar rats received cannula implants that bilaterally targeted the BLA. Long-term memory was examined using the step-through type of passive avoidance task. Behavioral stress was evoked by exposure to an elevated platform (EP) for 10, 20 and 30min. Post-training exposure to acute stress (30min) impaired the memory consolidation. In addition, pre-test exposure to acute stress-(20 and 30min) induced the impairment of memory retrieval. Interestingly, the memory impairment induced by post-training exposure to stress was restored in the animals that received 20- or 30-min pre-test stress exposure, suggesting stress-induced state-dependent memory retrieval. Post-training BLA-targeted injection of a selective 5-HT1A receptor antagonist, (S)-WAY-100135 (2μg/rat), prevented the impairing effect of stress on memory consolidation. Pre-test injection of the same doses of (S)-WAY-100135 that was targeted to the BLA also reversed stress-induced memory retrieval impairment. It should be considered that post-training or pre-test BLA-targeted injection of (S)-WAY-100135 (0.5-2μg/rat) by itself had no effect on the memory formation. Moreover, pre-test injection of (S)-WAY-100135 (2μg/rat) that targeted the BLA inhibited the stress-induced state-dependent memory retrieval. Taken together, our findings suggest that post-training or pre-test exposure to acute stress induced the impairment of memory consolidation, retrieval and state-dependent learning. The BLA 5-HT1A receptors have a critical role in learning and memory under stress.

  19. Endothelin Type A Receptor Genotype is a Determinant of Quantitative Traits of Metabolic Syndrome in Asian Hypertensive Families: A SAPPHIRe Study

    PubMed Central

    Ho, Low-Tone; Hsu, Yung-Pei; Hsiao, Chin-Fu; Ting, Chih-Tai; Shih, Kuang-Chung; Chuang, Lee-Ming; Masaki, Kamal; Grove, John; Quertermous, Thomas; Juan, Chi-Chung; Lin, Ming-Wei; Chiang, Shu-Chiung; Chen, Yii-Der I.

    2013-01-01

    Co-heritability of hypertension and insulin resistance (IR) within families not only implies genetic susceptibility may be responsible for these complex traits but also suggests a rational that biological candidate genes for hypertension may serve as markers for features of the metabolic syndrome (MetS). Thus we determined whether the T323C polymorphism (rs5333) of endothelin type A (ETA) receptor, a predominant receptor evoking potent vasoconstrictive action of endothelin-1, contributes to susceptibility to IR-associated hypertension in 1694 subjects of Chinese and Japanese origins. Blood pressures (BPs) and biochemistries were measured. Fasting insulin level, insulin-resistance homeostasis model assessment (HOMAIR) score, and area under curve of insulin concentration (AUCINS) were selected for assessing insulin sensitivity. Genotypes were obtained by methods of polymerase chain reaction-restriction fragment length polymorphism. Foremost findings were that minor allele frequency of the T323C polymorphism was noticeable lower in our overall Asian subjects compared to multi-national population reported in gene database; moreover both the genotypic and allelic frequencies of the polymorphism were significantly different between the two ethnic groups we studied. The genotype distributions at TT/TC/CC were 65, 31, 4% in Chinese and 51, 41, 8% in Japanese, respectively (p < 0.0001). Additionally, carriers of the C homozygote revealed characteristics of IR, namely significantly higher levels of fasting insulin, HOMAIR score, and AUCINS at 29.3, 35.3, and 39.3%, respectively, when compared to their counterparts with TT/TC genotypes in Chinese. Meanwhile, the CC genotype was associated with a higher level of high density lipoprotein cholesterol in Japanese. No association of the polymorphism with BP was observed. This study demonstrated for the first time that T323C polymorphism of ETA receptor gene was associated with an adverse insulin response in Chinese and a

  20. Protective effects of endothelin-1 on acute pancreatitis in rats.

    PubMed

    Kogire, M; Inoue, K; Higashide, S; Takaori, K; Echigo, Y; Gu, Y J; Sumi, S; Uchida, K; Imamura, M

    1995-06-01

    Endothelin-1, a 21-residue peptide isolated from vascular endothelial cells, has a broad spectrum of actions. To clarify the involvement of endothelin-1 in acute pancreatitis, we examined the effects of endothelin-1 and its receptor antagonist BQ-123 on cerulein-induced pancreatitis in rats. Rats were infused intravenously with heparin-saline (control), endothelin-1 (100 pmol/kg/hr), cerulein (5 micrograms/kg/hr), or cerulein plus endothelin-1 for 3.5 hr. In another experiment, cerulein or cerulein plus BQ-123 (3 mg/kg/hr) was infused. Infusion of cerulein caused hyperamylasemia and pancreatic edema. Endothelin-1, when infused with cerulein, decreased the extent of pancreatic edema with a significant increase in the pancreatic dry- to wet-weight ratio. Histological changes induced by cerulein were markedly attenuated when endothelin-1 was given with cerulein. In contrast, endothelin-receptor blockade with BQ-123 further augmented pancreatic edema caused by cerulein. The extent of inflammatory cell infiltration was greater than BQ-123 was given with cerulein. Endothelin-1 or BQ-123 had no influence on hyperamylasemia. This study suggests that endothelin-1 has protective effects on experimental acute pancreatitis.

  1. Endothelin receptor antagonists in pulmonary arterial hypertension.

    PubMed

    Dupuis, J; Hoeper, M M

    2008-02-01

    The endothelin (ET) system, especially ET-1 and the ET(A) and ET(B) receptors, has been implicated in the pathogenesis of pulmonary arterial hypertension (PAH). Together with prostanoids and phosphodiesterase 5 inhibitors, ET receptor antagonists have become mainstays in the current treatment of PAH. Three substances are currently available for the treatment of PAH. One of these substances, bosentan, blocks both ET(A) and ET(B) receptors, whereas the two other compounds, sitaxsentan and ambrisentan, are more selective blockers of the ET(A) receptor. There is ongoing debate as to whether selective or nonselective ET receptor blockade is advantageous in the setting of PAH, although there is no clear evidence that receptor selectivity is relevant with regard to the clinical effects of these drugs. For the time being, other features, such as safety profiles and the potential for pharmacokinetic interactions with other drugs used in the treatment of PAH, may be more important than selectivity or nonselectivity when selecting treatments for individual patients.

  2. Recovery from ketamine-induced amnesia by blockade of GABA-A receptor in the medial prefrontal cortex of mice.

    PubMed

    Farahmandfar, Maryam; Akbarabadi, Ardeshir; Bakhtazad, Atefeh; Zarrindast, Mohammad-Reza

    2017-03-06

    Ketamine and other noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonists are known to induce deficits in learning and cognitive performance sensitive to prefrontal cortex (PFC) functions. The interaction of a glutamatergic and GABAergic systems is essential for many cognitive behaviors. In order to understand the effect of γ-aminobutyric acid (GABA)/glutamate interactions on learning and memory, we investigated the effects of intra medial prefrontal cortex (mPFC) injections of GABAergic agents on ketamine-induced amnesia using a one-trial passive avoidance task in mice. Pre-training systemic administration of ketamine (5, 10 and 15mg/kg, i.p.) dose-dependently decreased the memory acquisition of a one-trial passive avoidance task. Pre-training intra-mPFC injection of muscimol, GABAA receptor agonist (0.05, 0.1 and 0.2μg/mouse) and baclofen GABAB receptor agonist (0.05, 0.1, 0.5 and 1μg/mouse), impaired memory acquisition. However, co-pretreatment of different doses of muscimol and baclofen with a lower dose of ketamine (5mg/kg), which did not induce amnesia by itself, caused inhibition of memory formation. Our data showed that sole pre-training administration of bicuculline, GABA-A receptor antagonist and phaclofen GABA-B receptor antagonist into the mPFC, did not affect memory acquisition. In addition, the amnesia induced by pre-training ketamine (15mg/kg) was significantly decreased by the pretreatment of bicuculline (0.005, 0.1 and 0.5μg/mouse). It can be concluded that GABAergic system of the mPFC is involved in the ketamine-induced impairment of memory acquisition.

  3. Neuroprotection by estradiol: a role of aromatase against spine synapse loss after blockade of GABA(A) receptors.

    PubMed

    Zhou, Lepu; Lehan, Nadine; Wehrenberg, Uwe; Disteldorf, Erik; von Lossow, Richard; Mares, Ute; Jarry, Hubertus; Rune, Gabriele M

    2007-01-01

    Estrogen has been suggested to be pro-epileptic by reducing GABA synthesis, resulting in increased spine density and a decreased threshold for seizures in the hippocampus, which, once they occur, are characterized by a dramatic spine loss in the affected brain areas. As considerable amounts of estradiol are synthesized in the hippocampus, in this study we focused on aromatase, the rate-limiting enzyme in estrogen synthesis in order to examine the role of locally synthesized estrogens in epilepsy. To this end, we first examined the effects of letrozole, a potent aromatase inhibitor, on GABA metabolism in single interneurons of hippocampal dispersion cultures. Letrozole downregulated estradiol release into the medium, as well as glutamate decarboxylase (GAD) expression and GABA synthesis, and decreased the number of GAD positive cells in the cultures. Next, we counted spine synapses and measured estradiol release of hippocampal slice cultures, in which GABA(A) receptors had been blocked by bicuculline, in order to mimic epileptic activity. Treatment of slice cultures with bicuculline resulted in a dramatic decrease in the number of spine synapses and in a significant suppression of estrogen synthesis. The decrease in synapse number in response to bicuculline was restored by combined application of estradiol and bicuculline. Surprisingly, estradiol alone had no effect on either spine synapse number or on GAD expression and GABA synthesis. "Rescue" of synapse number in "epileptic slices" by estradiol and maintenance of GABA metabolism by hippocampus-derived estradiol points to a neuroprotective role of aromatase in epilepsy. Re-filling of estradiol stores after their depletion due to overexcitation may therefore add to therapeutical strategies in epilepsy.

  4. Systemic modulation of serotonergic synapses via reuptake blockade or 5HT1A receptor antagonism does not alter perithreshold taste sensitivity in rats.

    PubMed

    Mathes, Clare M; Spector, Alan C

    2014-09-01

    Systemic blockade of serotonin (5HT) reuptake with paroxetine has been shown to increase sensitivity to sucrose and quinine in humans. Here, using a 2-response operant taste detection task, we measured the effect of paroxetine and the 5HT1A receptor antagonist WAY100635 on the ability of rats to discriminate sucrose, NaCl, and citric acid from water. After establishing individual psychometric functions, 5 concentrations of each taste stimulus were chosen to represent the dynamic portion of the concentration-response curve, and the performance of the rats to these stimuli was assessed after vehicle, paroxetine (7mg/kg intraperitoneally), and WAY100635 (0.3mg/kg subcutaneously; 1mg/kg intravenously) administration. Although, at times, overall performance across concentrations dropped, at most, 5% from vehicle to drug conditions, no differences relative to vehicle were seen on the parameters of the psychometric function (asymptote, slope, or EC50) after drug administration. In contrast to findings in humans, our results suggest that modulation of 5HT activity has little impact on sucrose detectability at perithreshold concentrations in rats, at least at the doses used in this task. In the rat model, the purported paracrine/neurocrine action of serotonin in the taste bud may work in a manner that does not impact overt taste detection behavior.

  5. Systemic Modulation of Serotonergic Synapses via Reuptake Blockade or 5HT1A Receptor Antagonism Does Not Alter Perithreshold Taste Sensitivity in Rats

    PubMed Central

    Spector, Alan C.

    2014-01-01

    Systemic blockade of serotonin (5HT) reuptake with paroxetine has been shown to increase sensitivity to sucrose and quinine in humans. Here, using a 2-response operant taste detection task, we measured the effect of paroxetine and the 5HT1A receptor antagonist WAY100635 on the ability of rats to discriminate sucrose, NaCl, and citric acid from water. After establishing individual psychometric functions, 5 concentrations of each taste stimulus were chosen to represent the dynamic portion of the concentration–response curve, and the performance of the rats to these stimuli was assessed after vehicle, paroxetine (7mg/kg intraperitoneally), and WAY100635 (0.3mg/kg subcutaneously; 1mg/kg intravenously) administration. Although, at times, overall performance across concentrations dropped, at most, 5% from vehicle to drug conditions, no differences relative to vehicle were seen on the parameters of the psychometric function (asymptote, slope, or EC50) after drug administration. In contrast to findings in humans, our results suggest that modulation of 5HT activity has little impact on sucrose detectability at perithreshold concentrations in rats, at least at the doses used in this task. In the rat model, the purported paracrine/neurocrine action of serotonin in the taste bud may work in a manner that does not impact overt taste detection behavior. PMID:25056731

  6. Chemical synthesis of tetracyclic terpenes and evaluation of antagonistic activity on endothelin-A receptors and voltage-gated calcium channels.

    PubMed

    Lu, Jianyu; Aguilar, Angelo; Zou, Bende; Bao, Weier; Koldas, Serkan; Shi, Aibin; Desper, John; Wangemann, Philine; Xie, Xinmin Simon; Hua, Duy H

    2015-09-01

    A class of tetracyclic terpenes was synthesized and evaluated for antagonistic activity of endothelin-1 (ET-1) induced vasoconstriction and inhibitory activity of voltage-activated Ca(2+) channels. Three repeated Robinson annulation reactions were utilized to construct the tetracyclic molecules. A stereoselective reductive Robinson annulation was discovered for the formation of optically pure tricyclic terpenes. Stereoselective addition of cyanide to the hindered α-face of tetracyclic enone (-)-18 was found and subsequent transformation into the aldehyde function was affected by the formation of bicyclic hemiiminal (-)-4. Six selected synthetic tetracyclic terpenes show inhibitory activities in ET-1 induced vasoconstriction in the gerbil spiral modiolar artery with putative affinity constants ranging between 93 and 319 nM. Moreover, one compound, (-)-3, was evaluated further and found to inhibit voltage-activated Ca(2+) currents but not to affect Na(+) or K(+) currents in dorsal root ganglion cells under similar concentrations. These observations imply a dual mechanism of action. In conclusion, tetracyclic terpenes represent a new class of hit molecules for the discovery of new drugs for the treatment of pulmonary hypertension and vascular related diseases.

  7. Chemical Synthesis of Tetracyclic Terpenes and Evaluation of Antagonistic Activity on Endothelin-A Receptors and Voltage-gated Calcium Channels

    PubMed Central

    Lu, Jianyu; Aguilar, Angelo; Zou, Bende; Bao, Weier; Koldas, Serkan; Aibin, Shi; Desper, John; Wangemann, Philine; Xie, Xinmin Simon; Hua, Duy H.

    2015-01-01

    A class of tetracyclic terpenes was synthesized and evaluated for antagonistic activity of endothelin-1 (ET-1) induced vasoconstriction and inhibitory activity of voltage-activated Ca2+ channels. Three repeated Robinson annulation reactions were utilized to construct the tetracyclic molecules. A stereoselective reductive Robinson annulation was discovered for the formation of optically pure tricyclic terpenes. Stereoselective addition of cyanide to the hindered α-face of tetracyclic enone (-)-18 was found and subsequent transformation into the aldehyde function was affected by the formation of bicyclic hemiiminal (-)-4. Six selected synthetic tetracyclic terpenes show inhibitory activities in ET-1 induced vasoconstriction in the gerbil spiral modiolar artery with putative affinity constants ranging between 93 and 319 nM. Moreover, one compound, (-)-3, was evaluated further and found to inhibit voltage-activated Ca2+ currents but not to affect Na+ or K+ currents in dorsal root ganglion cells under similar concentrations. These observations imply a dual mechanism of action. In conclusion, tetracyclic terpenes represent a new class of hit molecules for the discovery of new drugs for the treatment of pulmonary hypertension and vascular related diseases. PMID:26190460

  8. Chronic administration of an endothelin-A receptor antagonist improves exercise capacity in rats with myocardial infarction-induced congestive heart failure.

    PubMed

    Miyauchi, Takashi; Fujimori, Akira; Maeda, Seiji; Iemitsu, Motoyuki; Sakai, Satoshi; Shikama, Hisataka; Tanabe, Takumi; Matsuda, Mitsuo; Goto, Katsutoshi; Yamaguchi, Iwao

    2004-11-01

    The effects of long-term administration of YM598, a selective endothelin-A antagonist, on improving the exercise tolerance of chronic heart failure model rats were examined using a treadmill exercise loading test. Rats were acclimatized to the treadmill apparatus and the coronary artery was ligated to prepare a myocardial infarction-induced congestive heart failure (CHF) model. Starting 10 days postoperatively, when the acute phase of infarction was over, YM598 was administered orally once daily for approximately 25 weeks at a dose of 1 mg/kg. At weeks 20 and 24 the treadmill test was performed. YM598 prolonged running time, which had been shortened as a result of heart failure. The weights, relative to the body weight, of the left and right ventricles and lungs of surviving rats with CHF were significantly greater than those of sham-operated rats, suggesting hypertrophy of the ventricles and congestion of the lungs. Administration of YM598 markedly reduced ventricular hypertrophy and pulmonary congestion. Examination of cardiac function revealed that, in surviving CHF rats, the peak positive first derivative of left ventricular pressure was significantly lower, and left ventricular end-diastolic pressure, right ventricular systolic pressure and central venous pressure were significantly higher in comparison to sham-operated rats. These data demonstrate that, in rats with CHF, the contractile and diastolic capacity of the left ventricle decreased and pulmonary hypertension and systemic congestion occurred. Long-term administration of YM598 improved left ventricular function of CHF rats to the level of sham-operated rats, and reduced the workload placed on the right side of the heart. Histological examination revealed that long-term treatment with YM598 prevented fibrosis of the surviving left ventricular myocardium. In conclusion, long-term administration of YM598 to rats with CHF improved exercise tolerance and inhibited remodeling of cardiac muscles, leading to

  9. Endothelin-1 as a master regulator of whole-body Na+ homeostasis.

    PubMed

    Speed, Joshua S; Heimlich, J Brett; Hyndman, Kelly A; Fox, Brandon M; Patel, Vivek; Yanagisawa, Masashi; Pollock, Jennifer S; Titze, Jens M; Pollock, David M

    2015-12-01

    The current study was designed to determine whether vascular endothelial-derived endothelin-1 (ET-1) is important for skin Na(+) buffering. In control mice (C57BL/6J), plasma Na(+) and osmolarity were significantly elevated in animals on high- vs. low-salt (HS and LS, respectively) intake. The increased plasma Na(+) and osmolarity were associated with increased ET-1 mRNA in vascular tissue. There was no detectable difference in skin Na(+):H2O in HS fed mice (0.119 ± 0.005 mM vs. 0.127 ± 0.007 mM; LS vs. HS); however, skin Na(+):H2O was significantly increased by blockade of the endothelin type A receptor with ABT-627 (0.116 ± 0.006 mM vs. 0.137 ± 0.007 mM; LS vs. HS; half-maximal inhibitory concentration, 0.055 nM). ET-1 peptide content in skin tissue was increased in floxed control animals on HS (85.9 ± 0.9 pg/mg vs. 106.4 ± 6.8 pg/mg; P < 0.05), but not in vascular endothelial cell endothelin-1 knockout (VEET KO) mice (76.4 ± 5.7 pg/mg vs. 65.7 ± 7.9 pg/mg; LS vs. HS). VEET KO mice also had a significantly elevated skin Na(+):H2O (0.113 ± 0.007 mM vs. 0.137 ± 0.005 mM; LS vs. HS; P < 0.05). Finally, ET-1 production was elevated in response to increasing extracellular osmolarity in cultured human endothelial cells. These data support the hypothesis that increased extrarenal vascular ET-1 production in response to HS intake is mediated by increased extracellular osmolarity and plays a critical role in regulating skin storage of Na(+).

  10. Blockade of GABA, type A, receptors in the rat pontine reticular formation induces rapid eye movement sleep that is dependent upon the cholinergic system.

    PubMed

    Marks, G A; Sachs, O W; Birabil, C G

    2008-09-22

    The brainstem reticular formation is an area important to the control of rapid eye movement (REM) sleep. The antagonist of GABA-type A (GABA(A)) receptors, bicuculline methiodide (BMI), injected into the rat nucleus pontis oralis (PnO) of the reticular formation resulted in a long-lasting increase in REM sleep. Thus, one factor controlling REM sleep appears to be the number of functional GABA(A) receptors in the PnO. The long-lasting effect produced by BMI may result from secondary influences on other neurotransmitter systems known to have long-lasting effects. To study this question, rats were surgically prepared for chronic sleep recording and additionally implanted with guide cannulas aimed at sites in the PnO. Multiple, 60 nl, unilateral injections were made either singly or in combination. GABA(A) receptor antagonists, BMI and gabazine (GBZ), produced dose-dependent increases in REM sleep with GBZ being approximately 35 times more potent than BMI. GBZ and the cholinergic agonist, carbachol, produced very similar results, both increasing REM sleep for about 8 h, mainly through increased period frequency, with little reduction in REM latency. Pre-injection of the muscarinic antagonist, atropine, completely blocked the REM sleep-increase by GBZ. GABAergic control of REM sleep in the PnO requires the cholinergic system and may be acting through presynaptic modulation of acetylcholine release.

  11. Endothelin-1 as a master regulator of whole-body Na+ homeostasis

    PubMed Central

    Speed, Joshua S.; Heimlich, J. Brett; Hyndman, Kelly A.; Fox, Brandon M.; Patel, Vivek; Yanagisawa, Masashi; Pollock, Jennifer S.; Titze, Jens M.; Pollock, David M.

    2015-01-01

    The current study was designed to determine whether vascular endothelial-derived endothelin-1 (ET-1) is important for skin Na+ buffering. In control mice (C57BL/6J), plasma Na+ and osmolarity were significantly elevated in animals on high- vs. low-salt (HS and LS, respectively) intake. The increased plasma Na+ and osmolarity were associated with increased ET-1 mRNA in vascular tissue. There was no detectable difference in skin Na+:H2O in HS fed mice (0.119 ± 0.005 mM vs. 0.127 ± 0.007 mM; LS vs. HS); however, skin Na+:H2O was significantly increased by blockade of the endothelin type A receptor with ABT-627 (0.116 ± 0.006 mM vs. 0.137 ± 0.007 mM; LS vs. HS; half-maximal inhibitory concentration, 0.055 nM). ET-1 peptide content in skin tissue was increased in floxed control animals on HS (85.9 ± 0.9 pg/mg vs. 106.4 ± 6.8 pg/mg; P < 0.05), but not in vascular endothelial cell endothelin-1 knockout (VEET KO) mice (76.4 ± 5.7 pg/mg vs. 65.7 ± 7.9 pg/mg; LS vs. HS). VEET KO mice also had a significantly elevated skin Na+:H2O (0.113 ± 0.007 mM vs. 0.137 ± 0.005 mM; LS vs. HS; P < 0.05). Finally, ET-1 production was elevated in response to increasing extracellular osmolarity in cultured human endothelial cells. These data support the hypothesis that increased extrarenal vascular ET-1 production in response to HS intake is mediated by increased extracellular osmolarity and plays a critical role in regulating skin storage of Na+.—Speed, J. S., Heimlich, J. B., Hyndman, K. A., Fox, B. M., Patel, V., Yanagisawa, M., Pollock, J. S., Titze, J. M., Pollock, D. M. Endothelin-1 as a master regulator of whole-body Na+ homeostasis. PMID:26268928

  12. Endothelin in human brain and pituitary gland: Presence of immunoreactive endothelin, endothelin messenger ribonucleic acid, and endothelin receptors

    SciTech Connect

    Takahashi, K.; Ghatei, M.A.; Jones, P.M.; Murphy, J.K.; Lam, H.C.; O'Halloran, D.J.; Bloom, S.R. )

    1991-03-01

    The presence of immunoreactive (IR) endothelin, endothelin mRNA, and endothelin receptors in human brain and pituitary gland has been studied by RIA, Northern blot hybridization, and receptor assay. IR endothelin was detected in all five brain regions examined (cerebral cortex, cerebellum, brain stem, basal ganglia, and hypothalamus) (6-10 fmol/g wet wt) and spinal cord (22 +/- 6 fmol/g wet wt, n = 7, mean +/- SEM). Higher concentrations of IR endothelin were found in the pituitary gland (147 +/- 30 fmol/g wet wt). Fast protein liquid chromatographic analysis of the IR endothelin in pituitary gland showed a large IR peak in the position of endothelin-3 and a smaller peak in the position of endothelin-1, whereas IR endothelin in the hypothalamus and brain stem was mainly endothelin-1. Endothelin messenger RNA was detected by Northern blot hybridization in the pituitary but not in hypothalamus. The receptor assay showed that 125I-endothelin-1 binding sites were present in large numbers in all five brain regions but were much less abundant in the pituitary gland. Binding capacity and dissociation constant were 5052 +/- 740 fmol/mg protein and 0.045 +/- 0.007 nM in brain stem and 963 +/- 181 fmol/mg protein and 0.034 +/- 0.009 nM in hypothalamus. In the pituitary gland, there were two classes of binding sites for endothelin with dissociation constants of 0.059 +/- 0.002 nM (binding capacity = 418 +/- 63 fmol/mg protein) and 0.652 +/- 0.103 nM (binding capacity = 1717 +/- 200 fmol/mg protein). Endothelin-1, -2 and -3 were almost equipotent in displacing the binding (IC50 approximately 0.04 nM). These findings are in accord with the possibility that endothelin acts as a neurotransmitter, neuromodulator or neurohormone in man.

  13. Endothelin antagonists for diabetic and non-diabetic chronic kidney disease

    PubMed Central

    Kohan, Donald E; Pollock, David M

    2013-01-01

    Numerous pre-clinical studies have implicated endothelin-1 in the pathogenesis of diabetic and non-diabetic chronic kidney disease (CKD). Renal endothelin-1 production is almost universally increased in kidney disease. The pathologic effects of endothelin-1, including vasoconstriction, proteinuria, inflammation, cellular injury and fibrosis, are likely mediated by the endothelin A (ETA) receptor. ETA antagonism alone, and/or combined ETA/B blockade, reduces CKD progression. Based on the strong pre-clinical data, several clinical trials using ETA antagonists were conducted. Small trials involving acute intravenous endothelin receptor blockade suggest that ETA, but not ETB, blockade exerts protective renal and vascular effects in CKD patients. A large phase 3 trial (ASCEND) examined the effects of avosentan, an endothelin receptor antagonist, on renal disease progression in diabetic nephropathy. Proteinuria was reduced after 3–6 months of treatment. However the study was terminated due to increased morbidity and mortality associated with avosentan-induced fluid retention. Several phase 2 trials using avosentan at lower doses than in ASCEND, atrasentan or sitaxsentan (the latter two being highly ETA-selective) showed reductions in proteinuria on top of renin-angiotensin system blockade. Infrequent and clinically insignificant fluid retention was observed at the most effective doses. Additional trials using ETA blockers are ongoing or being planned in patients with diabetic nephropathy or focal segmental glomerulosclerosis. Moving forward, such studies must be conducted with careful patient selection and attention to dosing in order to minimize adverse side effects. Nonetheless, there is cause for optimism that this class of agents will ultimately prove to be effective for the treatment of CKD. PMID:23228194

  14. Submucosal microinfusion of endothelin and adrenaline mobilizes ECL-cell histamine in rat stomach, and causes mucosal damage: a microdialysis study.

    PubMed

    Bernsand, M; Ericsson, P; Bjorkqvist, M; Zhao, C-M; Hakanson, R; Norlen, P

    2003-10-01

    Rat stomach ECL cells release histamine in response to gastrin. Submucosal microinfusion of endothelin or adrenaline, known to cause vasoconstriction and gastric lesions, mobilized striking amounts of histamine. While the histamine response to gastrin is sustainable for hours, that to endothelin and adrenaline was characteristically short-lasting (1-2 h). The aims of this study were to identify the cellular source of histamine mobilized by endothelin and adrenaline, and examine the differences between the histamine-mobilizing effects of gastrin, and of endothelin and adrenaline. Endothelin, adrenaline or gastrin were administered by submucosal microinfusion. Gastric histamine mobilization was monitored by microdialysis. Local pretreatment with the H1-receptor antagonist mepyramine and the H2-receptor antagonist ranitidine did not prevent endothelin- or adrenaline-induced mucosal damage. Submucosal microinfusion of histamine did not cause damage. Acid blockade by ranitidine or omeprazole prevented the damage, suggesting that acid back diffusion contributes. Gastrin raised histidine decarboxylase (HDC) activity close to the probe, without affecting the histamine concentration. Endothelin and adrenaline lowered histamine by 50-70%, without activating HDC. Histamine mobilization declined upon repeated administration. Endothelin reduced the number of histamine-immunoreactive ECL cells locally, and reduced the number of secretory vesicles. Thus, unlike gastrin, endothelin (and adrenaline) is capable of exhausting ECL-cell histamine. Microinfusion of alpha-fluoromethylhistidine (known to deplete ECL cells but not mast cells of histamine) reduced the histamine-mobilizing effect of endothelin by 80%, while 1-week pretreatment with omeprazole enhanced it, supporting the involvement of ECL cells. Somatostatin or the prostanoid misoprostol inhibited gastrin-, but not endothelin-stimulated histamine release, suggesting that endothelin and gastrin mobilize histamine via

  15. Hypertension in an Animal Model of HELLP Syndrome is Associated With Activation of Endothelin 1.

    PubMed

    Morris, Rachael; Spencer, Shauna-Kay; Kyle, Patrick B; Williams, Jan Michael; Harris, Al'shondra; Owens, Michelle Y; Wallace, Kedra

    2016-01-01

    Women with hypertensive forms of pregnancy such as hemolysis-elevated liver enzymes-low platelet syndrome have increased circulating endothelin 1; however, the relationship between hypertension and endothelin 1 has not been studied. Using an animal model, we sought to determine whether there was an increased activation/dysfunction of endothelin 1, the effect of endothelin 1 receptor-A blockade on hypertension and other manifestations of hemolysis, elevated liver enzymes, and low platelets syndrome. On gestational day 12, timed-pregnant rats were infused with soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEndoglin; 4.7 and 7 µg/kg) via mini-osmotic pumps for 8 days. A subset of rats were treated with receptor-A antagonist (ABT-627, 5mg/kg) for 8 days. Rats with hemolysis-elevated liver enzymes-low platelet syndrome had significantly increased hypertension (P = .0001), circulating endothelin 1 (P = .03), and a significant 3.3- and 7.2-fold increase in preproendothelin messenger RNA (mRNA) expression in the placenta and liver (P = .01 and .04). Urinary protein:creatinine ratio was significantly increased in these animals (P = .0007), and circulating factors from these rats stimulated a significant increase in endothelial cell secretion of endothelin 1 (P = .001) in an in vitro assay. Blockade of the endothelin 1 receptor A significantly decreased hypertension (P = .001), circulating endothelin 1, and interleukin 17 (P = .004 and .003), placental preproendothelin mRNA expression (P = .016), and urinary protein:creatinine ratio (P = .007) in rats with hemolysis-elevated liver enzymes-low platelet syndrome. Blockade of the endothelin 1 receptor A significantly decreased hemolysis (P = .009), liver enzymes (P = .011), and significantly increased platelet levels (P = .03) and decreased circulating CD4+ and CD8+ T lymphocytes (P = .0004 and .0001) in rats infused with sFlt-1 and sEndoglin. These data support the hypothesis that endothelin 1 activation

  16. Celecoxib, but not indomethacin, ameliorates the hypertensive and perivascular fibrotic actions of cyclosporine in rats: Role of endothelin signaling

    SciTech Connect

    El-Mas, Mahmoud M.; Helmy, Maged W.; Ali, Rabab M.; El-Gowelli, Hanan M.

    2015-04-01

    The immunosuppressant drug cyclosporine (CSA) is used with nonsteroidal antiinflammatory drugs (NSAIDs) in arthritic conditions. In this study, we investigated whether NSAIDs modify the deleterious hypertensive action of CSA and the role of endothelin (ET) receptors in this interaction. Pharmacologic, protein expression, and histopathologic studies were performed in rats to investigate the roles of endothelin receptors (ET{sub A}/ET{sub B}) in the hemodynamic interaction between CSA and two NSAIDs, indomethacin and celecoxib. Tail-cuff plethysmography measurements showed that CSA (20 mg kg{sup −1} day{sup −1}, 10 days) increased systolic blood pressure (SBP) and heart rate (HR). CSA hypertension was associated with renal perivascular fibrosis and divergent changes in immunohistochemical signals of renal arteriolar ET{sub A} (increases) and ET{sub B} (decreases) receptors. While these effects of CSA were preserved in rats treated concomitantly with indomethacin (5 mg kg{sup −1} day{sup −1}), celecoxib (10 mg kg{sup −1} day{sup −1}) abolished the pressor, tachycardic, and fibrotic effects of CSA and normalized the altered renal ET{sub A}/ET{sub B} receptor expressions. Selective blockade of ET{sub A} receptors by atrasentan (5 mg kg{sup −1} day{sup −1}) abolished the pressor response elicited by CSA or CSA plus indomethacin. Alternatively, BQ788 (ET{sub B} receptor blocker, 0.1 mg kg{sup −1} day{sup −1}) caused celecoxib-sensitive elevations in SBP and potentiated the pressor response evoked by CSA. Together, the improved renovascular fibrotic and endothelin receptor profile (ET{sub A} downregulation and ET{sub B} upregulation) mediate, at least partly, the protective effect of celecoxib against the hypertensive effect of CSA. Clinically, the use of celecoxib along with CSA in the management of arthritic conditions might provide hypertension-free regimen. - Highlights: • Chronic CSA causes hypertension and renal perivascular fibrosis in rats.

  17. Endothelin and endothelin receptors in the renal and cardiovascular systems.

    PubMed

    Vignon-Zellweger, Nicolas; Heiden, Susi; Miyauchi, Takashi; Emoto, Noriaki

    2012-10-15

    Endothelin-1 (ET-1) is a multifunctional hormone which regulates the physiology of the cardiovascular and renal systems. ET-1 modulates cardiac contractility, systemic and renal vascular resistance, salt and water renal reabsorption, and glomerular function. ET-1 is responsible for a variety of cellular events: contraction, proliferation, apoptosis, etc. These effects take place after the activation of the two endothelin receptors ET(A) and ET(B), which are present - among others - on cardiomyocytes, fibroblasts, smooth muscle and endothelial cells, glomerular and tubular cells of the kidney. The complex and numerous intracellular pathways, which can be contradictory in term of functional response depending on the receptor type, cell type and physiological situation, are described in this review. Many diseases share an enhanced ET-1 expression as part of the pathophysiology. However, the use of endothelin blockers is currently restricted to pulmonary arterial hypertension, and more recently to digital ulcer. The complexity of the endothelin system does not facilitate the translation of the molecular knowledge to clinical applications. Endothelin antagonists can prevent disease development but secondary undesirable effects limit their usage. Nevertheless, the increasing understanding of the effects of ET-1 on the cardiac and renal physiology maintains the endothelin system as a promising therapeutic target.

  18. Evolution of endothelin receptors in vertebrates.

    PubMed

    Braasch, Ingo; Schartl, Manfred

    2014-12-01

    Endothelin receptors are G protein coupled receptors (GPCRs) of the β-group of rhodopsin receptors that bind to endothelin ligands, which are 21 amino acid long peptides derived from longer prepro-endothelin precursors. The most basal Ednr-like GPCR is found outside vertebrates in the cephalochordate amphioxus, but endothelin ligands are only present among vertebrates, including the lineages of jawless vertebrates (lampreys and hagfishes), cartilaginous vertebrates (sharks, rays, and chimaeras), and bony vertebrates (ray-finned fishes and lobe-finned vertebrates including tetrapods). A bona fide endothelin system is thus a vertebrate-specific innovation with important roles for regulating the cardiovascular system, renal and pulmonary processes, as well as for the development of the vertebrate-specific neural crest cell population and its derivatives. Expectedly, dysregulation of endothelin receptors and the endothelin system leads to a multitude of human diseases. Despite the importance of different types of endothelin receptors for vertebrate development and physiology, current knowledge on endothelin ligand-receptor interactions, on the expression of endothelin receptors and their ligands, and on the functional roles of the endothelin system for embryonic development and in adult vertebrates is very much biased towards amniote vertebrates. Recent analyses from a variety of vertebrate lineages, however, have shown that the endothelin system in lineages such as teleost fish and lampreys is more diverse and is divergent from the mammalian endothelin system. This diversity is mainly based on differential evolution of numerous endothelin system components among vertebrate lineages generated by two rounds of whole genome duplication (three in teleosts) during vertebrate evolution. Here we review current understanding of the evolutionary history of the endothelin receptor family in vertebrates supplemented with surveys on the endothelin receptor gene complement of

  19. Endothelin-1 mediated induction of extracellular matrix genes in strial marginal cells underlies strial pathology in Alport mice.

    PubMed

    Meehan, Daniel T; Delimont, Duane; Dufek, Brianna; Zallocchi, Marisa; Phillips, Grady; Gratton, Michael Anne; Cosgrove, Dominic

    2016-11-01

    Alport syndrome, a type IV collagen disorder, manifests as glomerular disease associated with hearing loss with thickening of the glomerular and strial capillary basement membranes (SCBMs). We have identified a role for endothelin-1 (ET-1) activation of endothelin A receptors (ETARs) in glomerular pathogenesis. Here we explore whether ET-1 plays a role in strial pathology. Wild type (WT) and Alport mice were treated with the ETAR antagonist, sitaxentan. The stria vascularis was analyzed for SCBM thickness and for extracellular matrix (ECM) proteins. Additional WT and Alport mice were exposed to noise or hypoxia and the stria analyzed for hypoxia-related and ECM genes. A strial marginal cell line cultured under hypoxic conditions, or stimulated with ET-1 was analyzed for expression of hypoxia-related and ECM transcripts. Noise exposure resulted in significantly elevated ABR thresholds in Alport mice relative to wild type littermates. Alport stria showed elevated expression of collagen α1(IV), laminin α2, and laminin α5 proteins relative to WT. SCBM thickening and elevated ECM protein expression was ameliorated by ETAR blockade. Stria from normoxic Alport mice and hypoxic WT mice showed upregulation of hypoxia-related, ECM, and ET-1 transcripts. Both ET-1 stimulation and hypoxia up-regulated ECM transcripts in cultured marginal cells. We conclude that ET-1 mediated activation of ETARs on strial marginal cells results in elevated expression of ECM genes and thickening of the SCBMs in Alport mice. SCBM thickening results in hypoxic stress further elevating ECM and ET-1 gene expression, exacerbating strial pathology.

  20. The endothelin B receptor plays a crucial role for the adhesion of neutrophils to the endothelium in sickle cell disease.

    PubMed

    Koehl, Bérengère; Nivoit, Pierre; El Nemer, Wassim; Lenoir, Olivia; Hermand, Patricia; Pereira, Catia; Brousse, Valentine; Guyonnet, Léa; Ghinatti, Giulia; Benkerrou, Malika; Colin, Yves; Le Van Kim, Caroline; Tharaux, Pierre-Louis

    2017-04-06

    Although the primary origin of sickle cell disease is a hemoglobin disorder, several cell types contribute considerably to the physiopathology of the disease. The adhesion of neutrophils to activated endothelium is critical in sickle cell disease pathophysiology and the targeting of neutrophils and their interactions with endothelium represent important opportunities for new therapeutics. We focused on endothelin-1, a mediator involved in neutrophil activation and recruitment in tissues, and we investigated the involvement of the endothelin receptors in interaction of neutrophils with endothelial cells. We used fluorescence intravital microscopy analyses of the microcirculation in sickle mice and quantitative microfluidic fluorescence microscopy of human blood. Both experiments on mouse model and patients indicate that blocking endothelin receptors, particularly ETB receptor highly influences neutrophils recruitment under inflammatory conditions in sickle cell disease. We show that human neutrophils display functional ETB receptors with calcium signaling capability leading to increased adhesion to the endothelium, through action on both endothelial cells and neutrophils. ETB intact function was also found to be required for TNFα-dependent upregulation of CD11b on neutrophils. Furthermore, we confirmed that human neutrophils synthesize endothelin-1 that may be involved in autocrine and paracrine pathophysiological actions. Thus, the endothelin-ETB axis should be considered as a cytokine-like potent pro-inflammatory pathway in sickle cell disease. Blockade of endothelin receptor, including ETB, may provide major benefits for preventing or treating vaso-occlusive crises of sickle cell patients.

  1. Endothelin-1 contributes to the Frank-Starling response in hypertrophic rat hearts.

    PubMed

    Piuhola, Jarkko; Szokodi, István; Kinnunen, Pietari; Ilves, Mika; deChâtel, Rudolf; Vuolteenaho, Olli; Ruskoaho, Heikki

    2003-01-01

    Endothelin-1 is involved in mechanical load-induced cardiac growth processes; it also has effects on contractility. The interaction of endothelin-1 and the Frank-Starling response is unknown. The present study aimed to characterize the role of endothelin-1 in the regulation of the Frank-Starling response, one of the major mechanisms regulating cardiac contractile force, in both normal and hypertrophied hearts. Nontransgenic rat hearts and hypertrophic hearts of hypertensive double transgenic rats harboring human angiotensinogen and renin genes were studied in a Langendorff isolated heart setup with a liquid-filled balloon inside the left ventricle used to measure contractile parameters. The rats were studied at compensated phase, before showing any signs of heart failure. Compensated hypertrophy in double transgenic rat hearts resulted in improved contractility at a given level of preload when compared with nontransgenic rat hearts. Hearts of both rat lines showed preserved Frank-Starling responses, that is, increased contractile function in response to increased end-diastolic pressure. The mixed endothelin A/B receptor antagonist bosentan attenuated the Frank-Starling response by 53% (P<0.01) in the double transgenic hearts but not in nontransgenic hearts. The diastolic parameters remained unaffected. The left ventricles of the double transgenic rat hearts showed an 82% higher level of endothelin type A receptor mRNA and a 25% higher level of immunoreactive endothelin-1 compared with nontransgenic rat hearts. The type 1 angiotensin II receptor antagonist CV-11974 had no significant effect on contractile function in response to load in either strain. These results show that endogenous endothelin-1 contributes to the Frank-Starling response in hypertrophied rat hearts by affecting systolic performance.

  2. Effects of Long-term Blockade of Vasopressin Receptor Types 1a and 2 on Cardiac and Renal Damage in a Rat Model of Hypertensive Heart Failure.

    PubMed

    Ikeda, Tomoyuki; Iwanaga, Yoshitaka; Watanabe, Heitaro; Morooka, Hanako; Akahoshi, Yasumitsu; Fujiki, Hiroyuki; Miyazaki, Shunichi

    2015-11-01

    The effects of chronic blockade of vasopressin type 1a receptors (V1aR) and the additive effects of a type 2 receptor (V2R) antagonist on the treatment of hypertension-induced heart failure and renal injury remain to be unknown. In this study, Dahl salt-sensitive hypertensive rats were chronically treated with a vehicle (CONT), a V1aR antagonist (OPC21268; OPC), a V2R antagonist (tolvaptan; TOLV), or a combination of OPC21268 and tolvaptan (OPC/TOLV) from the pre-hypertrophic stage (6 weeks). No treatment altered blood pressure during the study. Significant improvements were seen in median survival for the OPC and TOLV, and the OPC/TOLV showed a further improvement in Kaplan-Meier analysis. Echocardiography showed suppressed left ventricular hypertrophy in the OPC and OPC/TOLV at 11 weeks with improved function in all treatment groups by 17 weeks. In all treatment groups, improvements were seen in the following: myocardial histological changes, creatinine clearance, urinary albumin excretion, and renal histopathologic damage. Also, key mRNA levels were suppressed (eg, endothelin-1 and collagen). In conclusion, chronic V1aR blockade ameliorated disease progression in this rat model, with additive benefits from the combination of V1aR and V2R antagonists. It was associated with protection of both myocardial and renal damage, independent of blood pressure.

  3. Neural peptidase endothelin-converting enzyme 1 regulates endothelin 1–induced pruritus

    PubMed Central

    Kido-Nakahara, Makiko; Buddenkotte, Jörg; Kempkes, Cordula; Ikoma, Akihiko; Cevikbas, Ferda; Akiyama, Tasuku; Nunes, Frank; Seeliger, Stephan; Hasdemir, Burcu; Mess, Christian; Buhl, Timo; Sulk, Mathias; Müller, Frank-Ulrich; Metze, Dieter; Bunnett, Nigel W.; Bhargava, Aditi; Carstens, Earl; Furue, Masutaka; Steinhoff, Martin

    2014-01-01

    In humans, pruritus (itch) is a common but poorly understood symptom in numerous skin and systemic diseases. Endothelin 1 (ET-1) evokes histamine-independent pruritus in mammals through activation of its cognate G protein–coupled receptor endothelin A receptor (ETAR). Here, we have identified neural endothelin–converting enzyme 1 (ECE-1) as a key regulator of ET-1–induced pruritus and neural signaling of itch. We show here that ETAR, ET-1, and ECE-1 are expressed and colocalize in murine dorsal root ganglia (DRG) neurons and human skin nerves. In murine DRG neurons, ET-1 induced internalization of ETAR within ECE-1–containing endosomes. ECE-1 inhibition slowed ETAR recycling yet prolonged ET-1–induced activation of ERK1/2, but not p38. In a murine itch model, ET-1–induced scratching behavior was substantially augmented by pharmacological ECE-1 inhibition and abrogated by treatment with an ERK1/2 inhibitor. Using iontophoresis, we demonstrated that ET-1 is a potent, partially histamine-independent pruritogen in humans. Immunohistochemical evaluation of skin from prurigo nodularis patients confirmed an upregulation of the ET-1/ETAR/ECE-1/ERK1/2 axis in patients with chronic itch. Together, our data identify the neural peptidase ECE-1 as a negative regulator of itch on sensory nerves by directly regulating ET-1–induced pruritus in humans and mice. Furthermore, these results implicate the ET-1/ECE-1/ERK1/2 pathway as a therapeutic target to treat pruritus in humans. PMID:24812665

  4. Effects of antagonists for endothelin ET(A) and ET(B) receptors on coronary endothelial and myocardial function after ischemia-reperfusion in anesthetized goats.

    PubMed

    Climent, Belén; Fernández, Nuria; García-Villalón, Angel Luis; Monge, Luis; Sánchez, Ana; Diéguez, Godofredo

    2006-05-01

    To compare the effects of antagonists for endothelin ET(A) and ET(B) receptors on the action of ischemia-reperfusion on endothelial and myocardial function, 30 min of partial or total occlusion followed by 60 min of reperfusion of the left circumflex coronary artery was induced in anesthetized goats treated with intracoronary administration of saline (vehicle), BQ-123 (endothelin ET(A) receptors antagonist) or BQ-788 (endothelin ET(B) receptors antagonist). During reperfusion after partial occlusion, coronary vascular conductance and left ventricle dP/dt were decreased after saline or BQ-788, and they normalized after BQ-123. In these three groups of animals, the coronary effects of acetylcholine (3-100 ng) and sodium nitroprusside (1-10 microg) during reperfusion were as under control. During reperfusion after total occlusion, coronary vascular conductance and left ventricle dP/dt were decreased after saline, and they normalized after BQ-123 or BQ-788. In these three groups of animals, the coronary effects of acetylcholine but not those of sodium nitroprusside during reperfusion were decreased after saline, and they reversed after BQ-123 or BQ-788. Therefore, selective antagonists of endothelin ET(B) and ET(A) receptors may produce similar protection of coronary vasculature and myocardium against reperfusion after severe ischemia. Selective antagonists of endothelin ET(B) receptors, contrarily to those of endothelin ET(A) receptors, may be ineffective to protect coronary vasculature and myocardium against reperfusion after mild ischemia.

  5. Endothelin system in oral squamous carcinoma cells: specific siRNA targeting of ECE-1 blocks cell proliferation.

    PubMed

    Awano, Shuji; Dawson, Louise A; Hunter, Alison R; Turner, Anthony J; Usmani, Badar A

    2006-04-01

    The present study focused on the endothelin axis in human oral squamous cell carcinoma (SCC) cells. We investigated the expression and distribution of endothelin-1 (ET-1), its receptors (endothelin-A receptor (ET(A)R) and endothelin-B receptor (ET(B)R)) and isoforms of its specific converting enzyme (ECE-1a, 1b, 1c) and the report on their relative influences on cell proliferation. We also investigated the effect of an ECE-specific inhibitor (ECE-i) and siRNA targeting of the ECE-1 gene on SCC cell proliferation. We observed the expression of ET-1, ET(A)R, ET(B)R and all endothelin-converting enzyme-1 (ECE-1) isoforms in oral SCC cells, but only the expression of ET-1, ET(B)R and ECE-1 was increased when compared to normal human epidermal keratinocytes. ET-1 alone stimulated proliferation of oral SCC cells. Antagonists of either ET(A)R or ET(B)R inhibited ET-1-mediated proliferation. Decreased ECE-1 expression after ECE siRNA treatment reduced SCC cell proliferation. Antiproliferative effects were also observed by inhibiting ECE activity with ECE-i. In conclusion, the present study demonstrates that modulation of the endothelin system in oral SCC cells might provide a novel therapeutic protocol for oral cancer.

  6. The role of nitric oxide in the regional vasodilator effects of endothelin-1 in the rat.

    PubMed Central

    Fozard, J. R.; Part, M. L.

    1992-01-01

    1. The role of nitic oxide (NO) derived from L-arginine in the regional vasodilator effects of endothelin-1 has been investigated in anaesthetized, spontaneously hypertensive (SH) rats in which autonomic reflexes were abolished by ganglion blockade. The experimental design incorporated animals infused with phenylephrine to mimic the peripheral vasconstrictor effects of the NO biosynthesis inhibitors and a single dose per animal paradigm to obviate problems of tachyphylaxis to the vasodilator effects of endothelin-1. 2. Infusion of the inhibitor of NO synthase, N-monomethyl-L-arginine (L-NMMA) at a dose (5 mg kg-1 min-1) which maximally raised blood pressure did not influence either the fall in blood pressure or the vasodilator responses induced in the hindquarters and carotid vascular beds by endothelin-1 (1 nmol kg-1, i.v.) The duration (but not the initial magnitude) of the vasodepressor response to endothelin-1 was however significantly attenuated (by 49%) during infusion of the more potent inhibitor of NO synthase, NG-nitro-L-arginine methyl ester (L-NAME), 2 mg kg-1 min-1. 3. Increasing the dose of L-NAME to 10 and 25 mg kg-1min-1 significantly attenuated, but did not abolish, the falls in blood pressure and hindquarters vasodilator responses to acetylcholine, 1 microgram kg-1, and endothelin-1, 1 nmol kg-1 min-1. The effects were selective in that vasodepressor responses to the endothelium-independent vasodilator, sodium nitroprusside, 1-10 micrograms kg-1 min-1, were unaltered.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1628160

  7. Blockade of striatal adenosine A2A receptor reduces, through a presynaptic mechanism, quinolinic acid-induced excitotoxicity: possible relevance to neuroprotective interventions in neurodegenerative diseases of the striatum.

    PubMed

    Popoli, Patrizia; Pintor, Annita; Domenici, Maria Rosaria; Frank, Claudio; Tebano, Maria Teresa; Pèzzola, Antonella; Scarchilli, Laura; Quarta, Davide; Reggio, Rosaria; Malchiodi-Albedi, Fiorella; Falchi, Mario; Massotti, Marino

    2002-03-01

    The aim of the present study was to evaluate whether, and by means of which mechanisms, the adenosine A2A receptor antagonist SCH 58261 [5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine] exerted neuroprotective effects in a rat model of Huntington's disease. In a first set of experiments, SCH 58261 (0.01 and 1 mg/kg) was administered intraperitoneally to Wistar rats 20 min before the bilateral striatal injection of quinolinic acid (QA) (300 nmol/1 microl). SCH 58261 (0.01 but not 1 mg/kg, i.p.) did reduce significantly the effects of QA on motor activity, electroencephalographic changes, and striatal gliosis. Because QA acts by both increasing glutamate outflow and directly stimulating NMDA receptors, a second set of experiments was performed to evaluate whether SCH 58261 acted by preventing the presynaptic and/or the postsynaptic effects of QA. In microdialysis experiments in naive rats, striatal perfusion with QA (5 mm) enhanced glutamate levels by approximately 500%. Such an effect of QA was completely antagonized by pretreatment with SCH 58261 (0.01 but not 1 mg/kg, i.p.). In primary striatal cultures, bath application of QA (900 microm) significantly increased intracellular calcium levels, an effect prevented by the NMDA receptor antagonist MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate]. In this model, bath application of SCH 58261 (15-200 nm) tended to potentiate QA-induced calcium increase. We conclude the following: (1) the adenosine A2A receptor antagonist SCH 58261 has neuroprotective effects, although only at low doses, in an excitotoxic rat model of HD, and (2) the inhibition of QA-evoked glutamate outflow seems to be the major mechanism underlying the neuroprotective effects of SCH 58261.

  8. Ghrelin restores the endothelin 1/nitric oxide balance in patients with obesity-related metabolic syndrome.

    PubMed

    Tesauro, Manfredi; Schinzari, Francesca; Rovella, Valentina; Di Daniele, Nicola; Lauro, Davide; Mores, Nadia; Veneziani, Augusto; Cardillo, Carmine

    2009-11-01

    Obesity is associated with endothelial dysfunction related to decreased NO bioavailability, increased endothelin 1 vasoconstrictor activity, and decreased circulating ghrelin. Therefore, we tested whether exogenous ghrelin may have benefits to improve the balance between endothelin 1 and NO in patients with obesity-related metabolic syndrome. Vasoactive actions of endothelin 1 and NO were assessed in 8 patients with metabolic syndrome and 8 matched controls by evaluating forearm blood flow responses (strain-gauge plethysmography) to intra-arterial infusion of BQ-123 (endothelin A receptor antagonist; 10 nmol/min), followed by NG-monomethyl-L-arginine (NO synthase inhibitor; 4 micromol/min), before and after infusion of ghrelin (200 ng/min). In the absence of ghrelin, the vasodilator response to BQ-123 was greater in patients than in controls (P<0.001), whereas infusion of NG-monomethyl-L-arginine induced smaller vasoconstriction in patients than in controls (P=0.006). Importantly, exogenous ghrelin decreased the vasodilator response to BQ-123 (P=0.007 versus saline) and enhanced the magnitude of changes in forearm blood flow induced by NG-monomethyl-L-arginine (P=0.003) in patients but not in controls (both P>0.05). The favorable effect of ghrelin on endothelin A-dependent vasoconstriction was likely related to the stimulation of NO production, because no change in the vascular effect of BQ-123 was observed after ghrelin (P=0.44) in 5 patients with metabolic syndrome during continuous infusion of the NO donor sodium nitroprusside (0.2 microg/min). In patients with metabolic syndrome, ghrelin has benefits to normalize the balance between vasoconstrictor (endothelin 1) and vasodilating (NO) mediators, thus suggesting that this peptide has important peripheral actions to preserve vascular homeostasis in humans.

  9. EndothelinA-endothelinB receptor cross-talk in rat basilar artery in situ.

    PubMed

    Yoon, SeongHun; Zuccarello, Mario; Rapoport, Robert M

    2012-04-01

    The rationale for the therapeutic use of dual as opposed to selective endothelin (ET) receptor antagonists stems in part from cross-talk between the ET(A) and ET(B) receptors. However, whether ET(A)-ET(B) receptor cross-talk is present in the cerebral vasculature is difficult to discern since findings of cross-talk contrast even among the few reports available. Thus, this study tested whether ET(A)-ET(B) receptor cross-talk is present in the rat basilar artery. In an in situ cranial window, 0.1 μM sarafotoxin S6c, an ET(B) receptor agonist, relaxed basilar artery basal tone by 54%. ET-1 (3 nM) in the absence and presence of 10 μM BQ123, an ET(A) receptor agonist, induced 13% contraction and 15% relaxation, respectively. In contrast, the 3-nM ET-1 plateau contraction was relaxed by only ∼50% by 3-10 μM BQ123 and 10 μM BQ610, ET(A) receptor antagonists. N(ω)-nitro-L: -arginine, an NO synthase inhibitor, did not enhance contraction to 3 nM ET-1, suggesting that the partial relaxation of the ET-1 plateau contraction did not involve unmasked endothelial ET(B) receptor-mediated relaxation. The ∼50% ET-1 contraction that remained following ET(A) receptor antagonist was relaxed by 3-10 μM BQ788, consistent with an ET(B) receptor-mediated component of contraction. However, 10 μM BQ788 in the absence of prior ET(A) receptor antagonist did not cause relaxation. Subsequent BQ123 addition in the presence of BQ788 completely relaxed the ET-1 contraction. PD145065 (1 μM), an ET(A/B) receptor antagonist, completely relaxed 3-nM ET-1 contracted vessels in both the absence and presence of BQ123. These findings suggest that the inability of ET(A) receptor antagonist to completely relax the ET-1 plateau contraction in rat basilar artery is due to ET(A)-ET(B) receptor cross-talk.

  10. Time-dependent expression of endothelin-1 in lungs and the effects of TNF-α blocking peptide on acute lung injury in an endotoxemic rat model.

    PubMed

    Jesmin, Subrina; Yamaguchi, Naoto; Zaedi, Sohel; Nusrat Sultana, Sayeeda; Iwashima, Yoshio; Sawamura, Atsushi; Gando, Satoshi

    2011-02-01

    Endothelin (ET)-1 is a potent vasoconstrictor that has been implicated in the pathogenesis of a number of diseases, and some studies suggest that circulating ET-1 is elevated in sepsis. The present study investigated whether ET plays a role in sepsis-mediated acute lung injury and whether its expression could be down regulated by blockade of TNF-α in septic lung. Male Wistar rats at 8 weeks of age were administered with either saline or lipopolysaccharide (LPS) at different time points (1, 3, 6 and 10 h) and various tests were then performed. The features of acute lung injury were observed at 1 h after LPS administration, which gradually became severe with time. Systolic and diastolic pressures were reduced just about one hour after LPS administration, whereas pulmonary TNF-α levels were significantly increased at various time points after LPS administration. LPS induced a time-dependent expression of ET-1 and ET(A) receptor in the lungs compared to control, peaking and increasing by 3 fold at 6 h after induction of endotoxemia, whereas levels of ET(B) receptor, which has vasodilating effects, were remarkably down regulated time-dependently. We conclude that time-dependent increase of ET-1 and ET(A) receptor with the down regulation of ET(B) receptor may play a role in the pathogenesis of acute lung injury in endotoxemia. Finally, treatment of LPS-administered rats with TNF-α blocking peptide for three hours significantly suppressed levels of pulmonary ET-1. These data taken together, led us to conclude that differential alteration in ET expression and its receptors may be mediated by TNF-α and may, in part, account for the pathogenesis of acute lung injury in endotoxemia.

  11. Autoradiographic localization of endothelin-1 binding sites in porcine skin

    SciTech Connect

    Zhao, Y.D.; Springall, D.R.; Wharton, J.; Polak, J.M. )

    1991-01-01

    Autoradiographic techniques and {sup 125}I-labeled endothelin-1 were used to study the distribution of endothelin-1 binding sites in porcine skin. Specific endothelin-1 binding sites were localized to blood vessels (capillaries, deep cutaneous vascular plexus, arteries, and arterioles), the deep dermal and connective tissue sheath of hair follicles, sebaceous and sweat glands, and arrector pili muscle. Specific binding was inhibited by endothelin-2 and endothelin-3 as well as endothelin-1. Non-specific binding was found in the epidermis and the medulla of hair follicles. No binding was found in connective tissue or fat. These vascular binding sites may represent endothelin receptors, in keeping with the known cutaneous vasoconstrictor actions of the peptide. If all binding sites are receptors, the results suggest that endothelin could also regulate the function of sweat glands and may have trophic effects in the skin.

  12. Integrated control of pulmonary vascular tone by endothelin and angiotensin II in exercising swine depends on gender.

    PubMed

    de Beer, Vincent J; de Graaff, Henri J D; Hoekstra, Maaike; Duncker, Dirk J; Merkus, Daphne

    2010-06-01

    The lungs are now recognized as an active metabolic organ that is a major determinant of the plasma concentrations of the vasoconstrictors endothelin (ET) and ANG II. Several studies have suggested a complex interaction between ET and ANG II in the systemic and coronary vascular beds that is different at rest and during exercise. To date, the interaction between these vasoconstrictor peptides has barely been investigated in relation to the pulmonary vascular bed. Consequently, we investigated the integrated control of pulmonary vasomotor tone by ET and ANG II in 24 chronically instrumented swine (15 female and 9 male) at rest and during graded treadmill exercise. In the systemic circulation, ANG II type 1 (AT(1)) receptor blockade with irbesartan and mixed ET(A)/ET(B) blockade with tezosentan each produced vasodilation. The systemic vasodilator effect of ET(A)/ET(B) blockade was enhanced after AT(1) blockade in female swine, whereas a trend toward an increase was observed in male swine. In the pulmonary circulation, AT(1) receptor blockade had no effect on pulmonary vascular tone in male swine, whereas it resulted in an unexpected increase in pulmonary vasomotor tone in female swine. ET(A)/ET(B) receptor blockade did not result in a decrease in pulmonary vasomotor tone at rest but produced a decrease in vasomotor tone during exercise in both genders. This pulmonary vasodilation by ET(A)/ET(B) receptor blockade was enhanced after prior AT(1) blockade in female swine but not in male swine. In conclusion, in both the systemic and pulmonary circulation of female swine, ANG II inhibits the vasoconstrictor influence of ET. This interaction is gender specific. The observation that plasma ET levels were not altered by AT(1) blockade in either gender suggests that the interaction between these vasoconstrictors occurs locally in the vasculature.

  13. Glomerular actions of endothelin in vivo.

    PubMed Central

    Kon, V; Yoshioka, T; Fogo, A; Ichikawa, I

    1989-01-01

    In Munich-Wistar rats, a micropipette was inserted into a first-order branch of the left main renal artery and continuously infused with human/porcine endothelin (0.4 ng/min). Micropuncture measurements revealed substantial differences within the cortical microcirculation of the same left kidney: SNGFR was some 35% lower in glomeruli exposed to endothelin compared with non-endothelin-perfused glomeruli (P less than 0.005). Similarly, glomerular plasma flow rate was some 38% lower in the endothelin-exposed glomeruli (P less than 0.001). The hypoperfusion and hypofiltration in the endothelin-exposed glomeruli reflected an increase in resistances in the afferent and efferent arterioles. There was no difference in the value of the glomerular capillary ultrafiltration coefficient between the two populations of glomeruli. We also studied kidneys that underwent 25 min of renal artery clamping 48 h before study. Antiendothelin antibody infused into one of the branches of the main renal artery ameliorated the vasoconstriction characteristic of postischemic nephrons: within the cortical microcirculation, the SNGFR in glomeruli exposed to antiendothelin antibody was 27.0 +/- 3.1 nl/min as compared with 17.4 +/- 1.7 measured in glomeruli not perfused with the antibody (P less than 0.001). Similarly, glomerular plasma flow rate was higher in the glomeruli exposed to antiendothelin antibody (128.7 +/- 14.4 nl/min vs. 66.6 +/- 5.6, P less than 0.005). Resistances in both the afferent and efferent arterioles were substantially lower in the antibody-exposed glomeruli. It is, therefore, suggested that endothelin, presumably released from damaged endothelium, may play an important intermediary role in the hypoperfusion and hypofiltration observed in postischemic kidneys. Images PMID:2651481

  14. Regulation of human retinal blood flow by endothelin-1.

    PubMed

    Polak, Kaija; Luksch, Alexandra; Frank, Barbara; Jandrasits, Kerstin; Polska, Elzbieta; Schmetterer, Leopold

    2003-05-01

    There is evidence from in vitro and animal studies that endothelin is a major regulator of retinal blood flow. We set out to characterize the role of the endothelin-system in the blood flow control of the human retina. Two studies in healthy subjects were performed. The study design was randomized, placebo-controlled, double-masked, balanced, two-way crossover in protocol A and three way-way crossover in protocol B. In protocol A 18 healthy male subjects received intravenous endothelin-1 (ET-1) in a dose of 2.5 ng kg (-1)min(-1) for 30 min or placebo on two different study days and retinal vessel diameters were measured. In protocol B 12 healthy male subjects received ET-1 in stepwise increasing doses of 0, 1.25, 2.5 and 5 ng kg (-1)min(-1) (each infusion step over 20 min) in co-infusion with the specific ET(A)-receptor antagonist BQ123 (60 microg min (-1)) or placebo or BQ123 alone investigating retinal vessel diameters, retinal blood velocity and retinal blood flow. Measurements of retinal vessel size were done with the Zeiss retinal vessel analyzer. Measurements of blood velocities were done with bi-directional laser Doppler velocimetry. From these measurements retinal blood flow was calculated. In protocol A exogenous ET-1 tended to decrease retinal arterial diameter, but this effect was not significant versus placebo. No effect on retinal venous diameter was seen. In protocol B retinal venous blood velocity and retinal blood flow was significantly reduced after administration of exogenous ET-1. These effects were significantly blunted when BQ-123 was co-administered. By contrast, BQ-123 alone had no effect on retinal hemodynamic parameters. Concluding, BQ123 antagonizes the effects of exogenously administered ET-1 on retinal blood flow in healthy subjects. In addition, the results of the present study are compatible with the hypothesis that ET-1 exerts its vasoconstrictor effects in the retina mainly on the microvessels.

  15. An investigation into the direct and indirect venoconstrictor effects of endothelin-1 and big endothelin-1 in man.

    PubMed Central

    Haynes, W G; Moffat, S; Webb, D J

    1995-01-01

    1. Endothelin-1 is a potent endothelium-derived vasoconstrictor peptide that is generated through cleavage of its precursor big endothelin-1 by 'endothelin converting enzyme' (ECE) in resistance vessels, including those of the forearm vascular bed. In some animal tissues, but not in resistance vessels of healthy human subjects, endothelin-1 appears to potentiate the actions of the sympathetic nervous system. We examined whether ECE activity is present in human hand veins and whether endothelin-1 or big endothelin-1 potentiate sympathetically mediated venoconstriction. 2. Six healthy subjects received dorsal hand vein infusion of local, non-systemic doses of endothelin-1 (5 pmol min-1), big endothelin-1 (50 pmol min-1) and, as a control, sodium chloride (0.9%; w/v) for 90 min. Vein diameter was measured using the Aellig displacement technique. Sympathetically mediated venoconstriction was elicited using the single deep breath reflex. 3. Endothelin-1 caused a progressive decrease in hand vein diameter, by 49% at 90 min (95% confidence intervals [CI]: -68 to -30%; P = 0.0001). Vein diameter did not change significantly after 90 min infusion of big endothelin-1 (+3%; CI: -11 to +17%; P = 0.0007 vs endothelin-1; P = 0.40 vs baseline) or sodium chloride (+2%; CI: -12 to +16%; P = 0.0002 vs endothelin-1; P = 0.60 vs baseline). Venoconstriction to deep breath was not potentiated by endothelin-1. 4. These results suggest that, in contrast to the situation in forearm resistance vessels, there is little or no local ECE activity in human hand veins and that endothelin does not potentiate sympathetic responses in these cutaneous capacitance vessels. PMID:8554931

  16. Methamphetamine induces the release of endothelin.

    PubMed

    Seo, Jeong-Woo; Jones, Susan M; Hostetter, Trisha A; Iliff, Jeffrey J; West, G Alexander

    2016-02-01

    Methamphetamine is a potent psychostimulant drug of abuse that increases release and blocks reuptake of dopamine, producing intense euphoria, factors that may contribute to its widespread abuse. It also produces severe neurotoxicity resulting from oxidative stress, DNA damage, blood-brain barrier disruption, microgliosis, and mitochondrial dysfunction. Intracerebral hemorrhagic and ischemic stroke have been reported after intravenous and oral abuse of methamphetamine. Several studies have shown that methamphetamine causes vasoconstriction of vessels. This study investigates the effect of methamphetamine on endothelin-1 (ET-1) release in mouse brain endothelial cells by ELISA. ET-1 transcription as well as endothelial nitric oxide synthase (eNOS) activation and transcription were measured following methamphetamine treatment. We also examine the effect of methamphetamine on isolated cerebral arteriolar vessels from C57BL/6 mice. Penetrating middle cerebral arterioles were cannulated at both ends with a micropipette system. Methamphetamine was applied extraluminally, and the vascular response was investigated. Methamphetamine treatment of mouse brain endothelial cells resulted in ET-1 release and a transient increase in ET-1 message. The activity and transcription of eNOS were only slightly enhanced after 24 hr of treatment with methamphetamine. In addition, methamphetamine caused significant vasoconstriction of isolated mouse intracerebral arterioles. The vasoconstrictive effect of methamphetamine was attenuated by coapplication of the endothelin receptor antagonist PD145065. These findings suggest that vasoconstriction induced by methamphetamine is mediated through the endothelin receptor and may involve an endothelin-dependent pathway.

  17. Endothelin(A)-endothelin(B) receptor cross talk in endothelin-1-induced contraction of smooth muscle.

    PubMed

    Rapoport, Robert M; Zuccarello, Mario

    2012-11-01

    The efficacy of selective endothelin (ET) receptor antagonists may be limited by a functional interaction between the ET(A) and ET(B) receptors. This interaction, also termed "cross talk", is characterized by the dependency of the inhibition of an ET-1 response due to antagonism of one ET receptor subtype upon concomitant antagonism of the other ET receptor subtype. Although a reduction in ET(A)-ET(B) receptor cross talk would presumably increase the efficacy of selective ET receptor antagonists, an approach that accomplishes this aim is largely absent due to a lack of mechanistic understanding. Toward this goal, we evaluated the characteristics and potential dependencies of cross talk in smooth muscle. Smooth muscle was adopted as an exemplar not only because cross talk is widely reported in this tissue type, thereby allowing numerous comparisons, but also significant controversy surrounds the use of selective versus nonselective ET receptor antagonists in ET-1-related pathophysiologies involving smooth muscle. Based on this evaluation, we suggest that ET(A)-ET(B) receptor cross talk is a dynamic process directed by either or both ET receptor subtypes and expressed to varying magnitudes depending on the ET-1 and selective ET receptor antagonist concentrations, tone due to intraluminal pressure/stretch, agonists acting at receptors other than the ET(A)/ET(B) receptors, and endothelial/epithelial function. It is speculated that ET(A)-ET(B) receptor cross talk occurs through signal transduction pathways along with changes at the receptor level. Pharmacologic intervention of the signaling pathways could increase the therapeutic efficacy of ET receptor antagonists.

  18. 25 years of endothelin research: the next generation.

    PubMed

    Emoto, Noriaki; Vignon-Zellweger, Nicolas; Lopes, Rhéure Alves Moreira; Cacioppo, Joseph; Desbiens, Louisane; Kamato, Danielle; Leurgans, Thomas; Moorhouse, Rebecca; Straube, Julia; Wurm, Raphael; Heiden, Susi; Ergul, Adviye; Yanagisawa, Masashi; Barton, Matthias

    2014-11-24

    In the past three decades, endothelin and endothelin receptor antagonists have received great scientific and clinical interest, leading to the publication of more than 27,000 scientific articles since its discovery. The Thirteenth International Conference on Endothelin (ET-13) was held on September 8-11, 2013, at Tokyo Campus of the University of Tsukuba in Japan. Close to 300 scientists from 25 countries from around the world came to Tokyo to celebrate the anniversary of the discovery of the endothelin peptide discovered 25 years ago at the University of Tsukuba. This article summarizes some of the highlights of the conference, the anniversary celebration ceremony, and particularly the participation of next generation of endothelin researchers in endothelin science and the anniversary celebration. As a particular highlight, next generation endothelin researchers wrote a haiku (a traditional form of Japanese poetry originating from consisting of no more than three short verses and 27 on, or Japanese phonetic units) to describe the magic of endothelin science which they presented to the conference audience at the anniversary ceremony. The text of each haiku - both in its original language together with the English translation - is part of this article providing in an exemplary fashion how poetry can be bridged with science. Finally, we give an outlook towards the next 25 years of endothelin research.

  19. Cardiac expression patterns of endothelin-converting enzyme (ECE): implications for conduction system development.

    PubMed

    Sedmera, David; Harris, Brett S; Grant, Elizabeth; Zhang, Ning; Jourdan, Jane; Kurkova, Dana; Gourdie, Robert G

    2008-06-01

    The spatiotemporal distribution of the endothelin-converting enzyme (ECE) protein in the embryonic chick heart and the association of this polypeptide with the developing cardiac conduction system is described here for the first time. Further, we show how cardiac hemodynamic load directly affects ECE level and distribution. Endothelin (ET) is a cytokine involved in the inductive recruitment of Purkinje fibers. ET is produced by proteolytic cleavage of Big-ET by ECE. We generated an antibody against chick ECE recognizing a single band at approximately 70 kD to correlate the cardiac expression of this protein with that reported previously for its mRNA. ECE protein expression was more widespread compared to its mRNA, being present in endothelial cells, mesenchymal cells, and myocytes, and particularly enriched in the trabeculae and nascent ventricular conduction system. The myocardial expression was significantly modified under experimentally altered hemodynamic loading. In vivo, ET receptor blockade with bosentan delayed activation sequence maturation. These data support a role for ECE in avian cardiac conduction system differentiation and maturation.

  20. Cardioprotective effects of bosentan, a mixed endothelin type A and B receptor antagonist, during myocardial ischaemia and reperfusion in rats.

    PubMed

    Singh, Arya Dharamvir; Amit, Saxena; Kumar, Ojha Shreesh; Rajan, Mittal; Mukesh, Nandave

    2006-06-01

    The present study evaluated the cardioprotective potential of bosentan, a mixed endothelin type A and B receptor antagonist, in the myocardial ischaemia-reperfusion model of myocardial infarction. Adult male wistar rats (175-225 g) were divided into three groups: sham operated, non-myocardial ischaemia-reperfusion (SHAM); saline-treated myocardial ischaemia-reperfusion control (CON); bosentan-treated myocardial ischaemia-reperfusion (BOS). All animals were anaesthetized and subjected to 40 min. occlusion of left anterior descending coronary artery followed by 120 min. of reperfusion. Saline or drug was administered to the CON or BOS group, respectively, 20 min. after the left anterior descending coronary artery occlusion. Haemodynamic parameters viz. systolic arterial pressure, diastolic arterial pressure and heart rate were recorded throughout the experimental period. Hearts were subsequently excised and processed for histopathological and infarct size evaluation and for biochemical estimation of cardiac specific enzyme creatine kinase-MB (CK-MB) and myocardial malondialdehyde, a lipid peroxidation marker. Myocardial ischaemic reperfusion resulted in severe myocardial injury, depression of haemodynamic function, significant increase in malondialdehyde levels and decline in CK-MB isoenzyme activity in the heart tissue. Administration of bosentan (3 mg/kg, intravenously) slightly improved haemodynamic effects, decreased myocardial oxygen consumption, significantly (P<0.01) attenuated the rise in malondialdehyde levels and loss of myocardial CK-MB isoenzyme activity compared to the CON group, whereas bosentan administration significantly reduced the percentage area of fiber loss and infarct area. It is therefore concluded that endothelin-1 may mediate myocardial damage produced by ischaemia and reperfusion and that dual blockade of endothelinA and endothelinB receptors may have potential as a mode of therapy for myocardial infarction.

  1. A2aR antagonists: Next generation checkpoint blockade for cancer immunotherapy.

    PubMed

    Leone, Robert D; Lo, Ying-Chun; Powell, Jonathan D

    2015-01-01

    The last several years have witnessed exciting progress in the development of immunotherapy for the treatment of cancer. This has been due in great part to the development of so-called checkpoint blockade. That is, antibodies that block inhibitory receptors such as CTLA-4 and PD-1 and thus unleash antigen-specific immune responses against tumors. It is clear that tumors evade the immune response by usurping pathways that play a role in negatively regulating normal immune responses. In this regard, adenosine in the immune microenvironment leading to the activation of the A2a receptor has been shown to represent one such negative feedback loop. Indeed, the tumor microenvironment has relatively high concentrations of adenosine. To this end, blocking A2a receptor activation has the potential to markedly enhance anti-tumor immunity in mouse models. This review will present data demonstrating the ability of A2a receptor blockade to enhance tumor vaccines, checkpoint blockade and adoptive T cell therapy. Also, as several recent studies have demonstrated that under certain conditions A2a receptor blockade can enhance tumor progression, we will also explore the complexities of adenosine signaling in the immune response. Despite important nuances to the A2a receptor pathway that require further elucidation, studies to date strongly support the development of A2a receptor antagonists (some of which have already been tested in phase III clinical trials for Parkinson Disease) as novel modalities in the immunotherapy armamentarium.

  2. The heart as an extravascular target of endothelin-1 in ...

    EPA Pesticide Factsheets

    Exposure to particulate matter air pollution has been causally linked to cardiovascular disease in humans. Several broad and overlapping hypotheses describing the biological mechanisms by which particulate matter exposure leads to cardiovascular disease and cardiac dysfunction have been explored, though linkage with specific factors or genes remains limited. Given evidence pointing to autocrine/paracrine signaling systems as modulators of cardiac dysfunction, the present review highlights the emerging role of endothelins as mediators of cardiac dysfunction following particulate matter exposure. Endothelin-1 is a small multifunctional protein expressed in the pulmonary and cardiovascular system, known for its ability to constrict blood vessels. Although endothelin-1 can also directly and indirectly (via secondary signaling events) modulate cardiac contractility, heart rate, and rhythm, research on the role of endothelins in the context of air pollution has tended to focus on the vascular effects. The plausibility of endothelin as a mechanism underlying particulate matter-induced cardiac dysfunction is further supported by the therapeutic utility of certain endothelin receptor antagonists. Extravascular effects of endothelin on the heart could better explain one mechanism by which particulate matter exposure may lead to cardiac dysfunction. We propose and support the novel hypothesis that autocrine/paracrine signaling systems, such as endothelins, mediate cardiac

  3. Traceable Coulomb blockade thermometry

    NASA Astrophysics Data System (ADS)

    Hahtela, O.; Mykkänen, E.; Kemppinen, A.; Meschke, M.; Prunnila, M.; Gunnarsson, D.; Roschier, L.; Penttilä, J.; Pekola, J.

    2017-02-01

    We present a measurement and analysis scheme for determining traceable thermodynamic temperature at cryogenic temperatures using Coulomb blockade thermometry. The uncertainty of the electrical measurement is improved by utilizing two sampling digital voltmeters instead of the traditional lock-in technique. The remaining uncertainty is dominated by that of the numerical analysis of the measurement data. Two analysis methods are demonstrated: numerical fitting of the full conductance curve and measuring the height of the conductance dip. The complete uncertainty analysis shows that using either analysis method the relative combined standard uncertainty (k  =  1) in determining the thermodynamic temperature in the temperature range from 20 mK to 200 mK is below 0.5%. In this temperature range, both analysis methods produced temperature estimates that deviated from 0.39% to 0.67% from the reference temperatures provided by a superconducting reference point device calibrated against the Provisional Low Temperature Scale of 2000.

  4. The endothelin system and endothelin-converting enzyme in the brain: molecular and cellular studies.

    PubMed

    Barnes, K; Turner, A J

    1997-08-01

    The biologically active vasoactive peptides, the endothelins (ETs), are generated from inactive intermediates, the big endothelins, by a unique processing event catalysed by the zinc metalloprotease, endothelin converting enzyme (ECE). In this overview we examine the actions of endothelins in the brain, and focus on the structure and cellular locations of ECE. The heterogeneous distribution in the brain of ET-1, ET-2, and ET-3 is discussed in relation to their hemodynamic, mitogenic and proliferative properties as well as their possible roles as neurotransmitters. The cellular and subcellular localization of ECE in neuronal and in glial cells is compared with that of other brain membrane metalloproteases, neutral endopeptidase-24.11 (neprilysin), angiotensin converting enzyme and aminopeptidase N, which all function in neuropeptide processing and metabolism Unlike these ectoenzymes, ECE exhibits a dual localisation in the cell, being present on the plasma membrane and also, in some instances, being concentrated in a perinuclear region. This differential localization may reflect distinct targeting of different ECE isoforms, ECE-1 alpha, ECE-1 beta, and ECE-2.

  5. Endothelin receptor antagonists and cardiovascular diseases of aging.

    PubMed

    Love, M P; McMurray, J J

    2001-01-01

    Our understanding of the role of the endothelin system in human cardiovascular physiology and pathophysiology has evolved very rapidly since the initial description of its constituent parts in 1988. Endothelin-1 (ET-1) is the predominant endothelin isoform in the human cardiovascular system and has potent vasoconstrictor, mitogenic and antinatriuretic properties which have implicated it in the pathophysiology of a number of cardiovascular diseases. The effects of ET-1 have been shown to be mediated by 2 principal endothelin receptor subtypes: ET(A) and ET(B). The development of a range of peptidic and nonpeptidic endothelin receptor antagonists represents an exciting breakthrough in human cardiovascular therapeutics. Two main classes of endothelin receptor antagonist have been developed for possible human therapeutic use: ET(A)-selective and nonselective antagonists. Extensive laboratory and clinical research with these agents has highlighted their promise in various cardiovascular diseases. Randomised, placebo-controlled clinical trials have yielded very encouraging results in patients with hypertension and chronic heart failure with more preliminary data suggesting a possible role in the treatment and prevention of atherosclerosis and stroke. Much more research is needed, however, before endothelin receptor antagonists can be considered for clinical use.

  6. The Future of Endothelin Research: Scientific Mentoring and Beyond

    PubMed Central

    Barton, Matthias; Pollock, David M.

    2013-01-01

    Endothelium-dependent regulation of vascular tone was one of the key discoveries in physiology in the 1980s, including the characterization of endothelium-derived vasoactive factors such as endothelin. Young investigators, often while starting research as part of their PhD degree, have been instrumental in carrying out the work that led some of the most important discoveries in the endothelin field. This article reviews the importance of mentoring for research in general and for endothelin research in particular, including examples of outstanding young investigators that have been instrumental in some of the key discoveries in the endothelin field. Recognizing scientific excellence among young investigators has a long tradition in the history of the International Conferences on Endothelin. Winners of “Young Investigator Awards” of the past five endothelin conferences (ET-8, ET-9, ET-10, ET-11, and ET-12) are presented, as well as recipients of the “ET-12 Best Presentation Awards” established on the occasion of the Twelfth International Conference on Endothelin ET-12 in Cambridge in September 2011. PMID:22796368

  7. Role of nitrergic and endothelin pathways modulations in cisplatin-induced nephrotoxicity in male rats.

    PubMed

    Helmy, M W; Helmy, M M; Abd Allah, D M; Abo Zaid, A M; Mohy El-Din, M M

    2014-06-01

    Although the protective role of either nitric oxide (NO) or endothelin (ET) receptors modulation on the severity of cisplatin-induced nephrotoxicity has been recognized in previous studies including our own, the possible interaction between the two pathways remains obscure. In this study, we tested for the first time the possible interaction between the nitrergic and endothelin pathways in cisplatin-induced nephrotoxicity in male rats. Sprague Dawley male rats were divided into four groups: control (given a single dose of normal saline, i.p.), cisplatin (6 mg/kg, i.p.), cisplatin + sildenafil (2 mg/kg, i.p.), cisplatin + sildenafil + BQ-123 (1 mg/kg, i.p.). Each of the co-administered drugs was given in two doses; one hour before and one day after the cisplatin dose. Acute cisplatin administration resulted in significant increases in blood urea nitrogen (BUN) and serum creatinine levels at 96 hours following cisplatin injection. Increased levels of malondialdehyde (MDA), tumor necrosis factor-α (TNF-α) and caspase-3, decreased nitrite/nitrate level and superoxide dismutase (SOD) activity in kidney homogenates were also observed following cisplatin injection, in addition to a typical 'acute tubular necrosis' pattern. According to the obtained results, the co-adminstration of sildenafil alone with cisplatin offered a reno-protective effect comparable to that obtained following the concurrent administration of both sildenafil and the selective ET-A receptor antagonist BQ-123. Thus, the current study is the first to reveal that the presence of an intact NO/cGMP system may offer a moderate reno-protective effect against cisplatin-induced nephrotoxicity even in the presence of ET-A-mediated vasoconstriction, suggesting the absence of obvious functional interaction between the nitrergic and endothelin pathways in cisplatin-induced nephrotoxicity in male rats.

  8. Endothelin-1 and endothelin receptors in the basilar artery of the capybara.

    PubMed

    Loesch, Andrzej; Gajkowska, Barbara; Dashwood, Michael R; Fioretto, Emerson T; Gagliardo, Karina M; Lima, Ana R De; Ribeiro, Antonio A C M

    2005-02-01

    Little is known about cerebral vasculature of capybara, which seems may serve as a natural model of studying changes in cerebral circulation due to internal carotid artery atrophy at animal sexual maturation. This is the first study of the light- and electron-immunocytochemical localisation of endothelin-1 (ET-1) and ETA and ETB endothelin receptors in the basilar artery of capybaras (6 to 12-month-old females and males) using an ExtrAvidin detection method. All animals examined showed similar patterns of immunoreactivity. Immunoreactivity for ET-1 was detected in the endothelium and adventitial fibroblasts, whilst immunoreactivity for ETA and ETB receptors was present in the endothelium, vascular smooth muscle, perivascular nerves and fibroblasts. In endothelial cells immunoreactivity to ET-1 was pronounced in the cytoplasm or on the granular endoplasmic reticulum. Similar patterns of immunolabelling were observed for ETA and ETB receptors, though cytoplasmic location of clusters of immunoprecipitate seems dominant. These results suggest that the endothelin system is present throughout the wall of the basilar artery of capybara.

  9. Vascular Dysfunction in Pneumocystis-Associated Pulmonary Hypertension Is Related to Endothelin Response and Adrenomedullin Concentration.

    PubMed

    Siemsen, Dan W; Dobrinen, Erin; Han, Soo; Chiocchi, Kari; Meissner, Nicole; Swain, Steve D

    2016-02-01

    Pulmonary hypertension subsequent to an infectious disease can be due to vascular structural remodeling or to functional alterations within various vascular cell types. In our previous mouse model of Pneumocystis-associated pulmonary hypertension, we found that vascular remodeling was not responsible for observed increases in right ventricular pressures. Here, we report that the vascular dysfunction we observed could be explained by an enhanced response to endothelin-1 (20% greater reduction in lumen diameter, P ≤ 0.05), corresponding to an up-regulation of similar magnitude (P ≤ 0.05) of the endothelin A receptor in the lung tissue. This effect was potentially augmented by a decrease in production of the pulmonary vasodilator adrenomedullin of almost 70% (P ≤ 0.05). These changes did not occur in interferon-γ knockout mice similarly treated, which do not develop pulmonary hypertension under these circumstances. Surprisingly, we did not observe any relevant changes in the vascular endothelial nitric oxide synthase vasodilatory response, which is a common potential site of inflammatory alterations to pulmonary vascular function. Our results indicate the diverse mechanisms by which inflammatory responses to prior infections can cause functionally relevant changes in vascular responses in the lung, promoting the development of pulmonary hypertension.

  10. Identification of the endothelin-1 receptor in the chick heart

    SciTech Connect

    Miyazaki, H.; Kondoh, M.; Watanabe, H.; Hayashi, T.; Murakami, K.; Takahashi, M.; Yanagisawa, M.; Kimura, S.; Goto, K.; Masaki, T.

    1989-01-01

    This study suggests that binding sites for endothelin-1 (ET-1) are distinct from those for dihydropyridine (DHP)-sensitive, voltage-dependent Ca2+ channels and that ET-1 has its own specific receptors in chick cardiac membranes.

  11. Endothelin in cerebral vasospasm. Clinical and experimental results.

    PubMed

    Zimmermann, M

    1997-06-01

    Since their discovery in 1988, endothelins have attracted scientific interest because of their extremely potent and long lasting vasoconstrictive effects. In the clinical part of the study plasma and cerebrospinal fluid (CSF) concentrations of big endothelin-1, endothelin-1 and endothelin-3 in patients with aneurysmal subarachnoid hemorrhage (SAH) were measured serially for 2 weeks after the onset of SAH. Big endothelin-1 was the predominant peptide present in CSF. The CSF concentrations of big ET-1, ET-1 and ET-3 were significantly higher in older than in younger patients. In patients with cerebral vasospasm postoperative concentrations of endothelins in the CSF remained at or were increased above levels measured before surgery. The volume of hematoma in the basal cisterns was predictive of the concentrations of endothelins in CSF. In the experimental study the efficacy of the orally active endothelin-receptor-antagonist RO 47-0203 for the prevention of cerebral vasospasm after experimental SAH, using the canine two-hemorrhage model, was investigated. Twenty-eight beagle dogs were used in this laboratory experiment. Fourteen animals each were assigned to the treatment and to the control group. In the treatment group each dog received two single doses of 30 mg/kg RO 47-0203 orally per day. The diameter of the basilar artery decreased from 1.36 +/- 0.17 mm at day 1 to 1.19 +/- 0.23 mm at day 8 in the treatment group while in the control group the vessel diameter decreased from 1.48 +/- 0.19 mm at day 1 to 1.02 +/- 0.22 mm at day 8. These results corresponded to a decrease of vessel diameter of 13.1% +/- 11.2% in the treatment group and a decrease of vessel diameter of 30.7% +/- 12.4% in the control group (p < 0.001). Concentrations of endothelin-1 in CSF significantly increased with time after SAH. These results underline the important role of endothelin in the development of cerebral vasospasm, and gives for the first time evidence that prevention of cerebral

  12. Distinct Actions of Endothelin A-Selective Versus Combined Endothelin A/B Receptor Antagonists in Early Diabetic Kidney Disease

    PubMed Central

    Saleh, Mohamed A.; Pollock, Jennifer S.

    2011-01-01

    Selective endothelin A (ETA) and combined ETA and ETB receptor antagonists are being investigated for use in treating diabetic nephropathy. However, the receptor-specific mechanisms responsible for producing the potential benefits have not been discerned. Thus, we determined the actions of ETA and ETB receptors on measures of glomerular function and renal inflammation in the early stages of diabetic renal injury in rats through the use of selective and combined antagonists. Six weeks after streptozotocin (STZ)-induced hyperglycemia, rats were given 2R-(4-methoxyphenyl)-4S-(1,3-benzodioxol-5-yl)-1-(N,N-di(n-butyl)aminocarbonyl-methyl)-pyrrolidine-3R-carboxylic acid (ABT-627) (5 mg/kg/day), a selective ETA antagonist; (2R,3R,4S)-4-(benzo[d][1,3]dioxol-5-yl)-2-(3-fluoro-4-methoxyphenyl)-1-(2-(N-propylpentylsulfonamido)ethyl)pyrrolidine-3-carboxylic acid hydrochloride (A-182086) (10 mg/kg/day), a combined ETA/B antagonist; or vehicle for 1 week. Sham controls received STZ vehicle (saline). Hyperglycemia led to significant proteinuria, increased glomerular permeability to albumin (Palb), nephrinuria, and an increase in total matrix metalloprotease (MMP) and transforming growth factor-β1 (TGF-β1) activities in glomeruli. Plasma and glomerular soluble intercellular adhesion molecule-1 (sICAM-1) and monocyte chemoattractant protein-1 (MCP-1) were elevated after 7 weeks of hyperglycemia. Daily administration of both ABT-627 and A-182086 for 1 week significantly attenuated proteinuria, the increase in Palb, nephrinuria, and total MMP and TGF-β1 activity. However, glomerular sICAM-1 and MCP-1 expression was attenuated with ABT-627, but not A-182086, treatment. In summary, both selective ETA and combined ETA/B antagonists reduced proteinuria and glomerular permeability and restored glomerular filtration barrier component integrity, but only ETA-selective blockade had anti-inflammatory and antifibrotic effects. We conclude that selective ETA antagonists are more likely to be

  13. Role of endothelin-1 in mediating changes in cardiac sympathetic nerve activity in heart failure.

    PubMed

    Abukar, Yonis; May, Clive N; Ramchandra, Rohit

    2016-01-01

    Heart failure (HF) is associated with increased sympathetic nerve activity to the heart (CSNA), which is directly linked to mortality in HF patients. Previous studies indicate that HF is associated with high levels of plasma endothelin-1 (ET-1), which correlates with the severity of the disease. We hypothesized that blockade of endothelin receptors would decrease CSNA. The effects of intravenous tezosentan (a nonselective ETA and ETB receptor antagonist) (8 mg·kg(-1)·h(-1)) on resting levels of CSNA, arterial pressure, and heart rate were determined in conscious normal sheep (n = 6) and sheep with pacing-induced HF (n = 7). HF was associated with a significant decrease in ejection fraction (from 74 ± 2% to 38 ± 1%, P < 0.001) and a significant increase in resting levels of CSNA burst incidence (from 56 ± 11 to 87 ± 2 bursts/100 heartbeats, P < 0.01). Infusion of tezosentan for 60 min significantly decreased resting mean aterial pressure (MAP) in both normal and HF sheep (-8 ± 4 mmHg and -4 ± 3 mmHg, respectively; P < 0.05). This was associated with a significant decrease in CSNA (by 25 ± 26% of control) in normal sheep, but there was no change in CSNA in HF sheep. Calculation of spontaneous baroreflex gain indicated significant impairment of the baroreflex control of HR after intravenous tezosentan infusion in normal animals but no change in HF animals. These data suggest that endogenous levels of ET-1 contribute to the baseline levels of CSNA in normal animals, but this effect is absent in HF.

  14. Smooth Muscle Endothelin B Receptors Regulate Blood Pressure but Not Vascular Function or Neointimal Remodeling.

    PubMed

    Miller, Eileen; Czopek, Alicja; Duthie, Karolina M; Kirkby, Nicholas S; van de Putte, Elisabeth E Fransen; Christen, Sibylle; Kimmitt, Robert A; Moorhouse, Rebecca; Castellan, Raphael F P; Kotelevtsev, Yuri V; Kuc, Rhoda E; Davenport, Anthony P; Dhaun, Neeraj; Webb, David J; Hadoke, Patrick W F

    2017-02-01

    The role of smooth muscle endothelinB (ETB) receptors in regulating vascular function, blood pressure (BP), and neointimal remodeling has not been established. Selective knockout mice were generated to address the hypothesis that loss of smooth muscle ETB receptors would reduce BP, alter vascular contractility, and inhibit neointimal remodeling. ETB receptors were selectively deleted from smooth muscle by crossing floxed ETB mice with those expressing cre-recombinase controlled by the transgelin promoter. Functional consequences of ETB deletion were assessed using myography. BP was measured by telemetry, and neointimal lesion formation induced by femoral artery injury. Lesion size and composition (day 28) were analyzed using optical projection tomography, histology, and immunohistochemistry. Selective deletion of ETB was confirmed by genotyping, autoradiography, polymerase chain reaction, and immunohistochemistry. ETB-mediated contraction was reduced in trachea, but abolished from mesenteric veins, of knockout mice. Induction of ETB-mediated contraction in mesenteric arteries was also abolished in these mice. Femoral artery function was unaltered, and baseline BP modestly elevated in smooth muscle ETB knockout compared with controls (+4.2±0.2 mm Hg; P<0.0001), but salt-induced and ETB blockade-mediated hypertension were unaltered. Circulating endothelin-1 was not altered in knockout mice. ETB-mediated contraction was not induced in femoral arteries by incubation in culture medium or lesion formation, and lesion size was not altered in smooth muscle ETB knockout mice. In the absence of other pathology, ETB receptors in vascular smooth muscle make a small but significant contribution to ETB-dependent regulation of BP. These ETB receptors have no effect on vascular contraction or neointimal remodeling.

  15. The Thirteenth International Conference on Endothelin (ET-13), Tokyo, 2013.

    PubMed

    Emoto, Noriaki; Yanagisawa, Masashi

    2014-11-24

    The Thirteenth International Conference on Endothelin (ET-13) was held from September 8-11, 2013 in Tokyo, Japan chaired by Noriaki Emoto, Kobe Pharmaceutical University, Japan, and Takashi Miyauchi, University of Tsukuba, Japan and held on the Tokyo Campus of Tsukuba University. The International Conferences on Endothelin were launched in December of 1988 shortly after the discovery of endothelin and organized by Sir John Vane, laureate of the Nobel Prize in Physiology or Medicine 1982, as the Conference Chair at The William Harvey Research Institute, London. Since then, the conference has been held every two years alternating between North America, Europe and Asia. In 2013, the conference was again held in Asia and also marked the 25th anniversary of the discovery of endothelin at University of Tsukuba. The 25th anniversary of the discovery of endothelin was celebrated by almost 300 attendees from 25 different countries, the largest number of delegates in the recent history of the conference. Conference delegates who traveled to Japan were from Argentina, Australia, Austria, Brazil, Canada, China, Czech Republic, Denmark, France, Germany, Greece, Hong Kong, Hungary, Indonesia, Italy, Japan, Korean Republic, Netherlands, Sweden, Switzerland, Taiwan, Turkey, United Kingdom, United States, and from Vietnam. In this article we summarize the conference highlights, its speakers, and some of the festivities related to the celebration of the 25th anniversary of the discovery of endothelin.

  16. Embryonic expression of endothelins and their receptors in lamprey and frog reveals stem vertebrate origins of complex Endothelin signaling

    PubMed Central

    Square, Tyler; Jandzik, David; Cattell, Maria; Hansen, Andrew; Medeiros, Daniel Meulemans

    2016-01-01

    Neural crest cells (NCCs) are highly patterned embryonic cells that migrate along stereotyped routes to give rise to a diverse array of adult tissues and cell types. Modern NCCs are thought to have evolved from migratory neural precursors with limited developmental potential and patterning. How this occurred is poorly understood. Endothelin signaling regulates several aspects of NCC development, including their migration, differentiation, and patterning. In jawed vertebrates, Endothelin signaling involves multiple functionally distinct ligands (Edns) and receptors (Ednrs) expressed in various NCC subpopulations. To test the potential role of endothelin signaling diversification in the evolution of modern, highly patterned NCC, we analyzed the expression of the complete set of endothelin ligands and receptors in the jawless vertebrate, the sea lamprey (Petromyzon marinus). To better understand ancestral features of gnathostome edn and ednr expression, we also analyzed all known Endothelin signaling components in the African clawed frog (Xenopus laevis). We found that the sea lamprey has a gnathsotome-like complement of edn and ednr duplicates, and these genes are expressed in patterns highly reminiscent of their gnathostome counterparts. Our results suggest that the duplication and specialization of vertebrate Endothelin signaling coincided with the appearance of highly patterned and multipotent NCCs in stem vertebrates. PMID:27677704

  17. Endothelin receptor polymorphisms in the cardiovascular system: potential implications for therapy and screening.

    PubMed

    Holzhauser, Luise; Zolty, Ronald

    2014-11-01

    Since its discovery in 1988, the endothelin system has been employed in multiple physiological and pathological roles. Endothelin-1 (ET-1) is not only a major regulator of vascular tone and cardiac contractility but also exerts mitogenic effects and is involved in inflammatory responses. ET-1 acts via two endothelin receptors located mainly on smooth muscle and endothelial cells through complex intracellular pathways differing between receptors and cell types. Polymorphisms of the endothelin receptor A have been associated not only with the risk in pulmonary arterial hypertension (PAH), systolic heart failure and systemic hypertension but are also of prognostic significance in dilated cardiomyopathy. Polymorphisms of endothelin receptors might lead to altered endothelin signaling and influence the response to endothelin receptor antagonist therapy in PAH in light of pharmacogenetics. This review will summarize the role of ET-1 within major cardiovascular pathologies and discuss endothelin receptor polymorphisms with special emphasis on potential therapeutic and screening implications.

  18. Endothelin Regulates Porphyromonas gingivalis-Induced Production of Inflammatory Cytokines

    PubMed Central

    Kim, Ji-Hye; Lee, Dong Eun; Kang, Si-Mook; Lee, So Yun; Choi, Lin; Sun, Ji Su; Kim, Seul Ki; Park, Wonse; Kim, Baek Il; Yoo, Yun-Jung; Chang, Inik; Shin, Dong Min

    2016-01-01

    Periodontitis is a very common oral inflammatory disease that results in the destruction of supporting connective and osseous tissues of the teeth. Although the exact etiology is still unclear, Gram-negative bacteria, especially Porphyromonas gingivalis in subgingival pockets are thought to be one of the major etiologic agents of periodontitis. Endothelin (ET) is a family of three 21-amino acid peptides, ET-1, -2, and -3, that activate G protein-coupled receptors, ETA and ETB. Endothelin is involved in the occurrence and progression of various inflammatory diseases. Previous reports have shown that ET-1 and its receptors, ETA and ETB are expressed in the periodontal tissues and, that ET-1 levels in gingival crevicular fluid are increased in periodontitis patients. Moreover, P. gingivalis infection has been shown to induce the production of ET-1 along with other inflammatory cytokines. Despite these studies, however, the functional significance of endothelin in periodontitis is still largely unknown. In this study, we explored the cellular and molecular mechanisms of ET-1 action in periodontitis using human gingival epithelial cells (HGECs). ET-1 and ETA, but not ETB, were abundantly expressed in HGECs. Stimulation of HGECs with P. gingivalis or P. gingivalis lipopolysaccharide increased the expression of ET-1 and ETA suggesting the activation of the endothelin signaling pathway. Production of inflammatory cytokines, IL-1β, TNFα, and IL-6, was significantly enhanced by exogenous ET-1 treatment, and this effect depended on the mitogen-activated protein kinases via intracellular Ca2+ increase, which resulted from the activation of the phospholipase C/inositol 1,4,5-trisphosphate pathway. The inhibition of the endothelin receptor-mediated signaling pathway with the dual receptor inhibitor, bosentan, partially ameliorated alveolar bone loss and immune cell infiltration. These results suggest that endothelin plays an important role in P. gingivalis

  19. Coulomb-blockade and Pauli-blockade magnetometry

    NASA Astrophysics Data System (ADS)

    Széchenyi, Gábor; Pályi, András

    2017-01-01

    Scanning-probe magnetometry is a valuable experimental tool to investigate magnetic phenomena at the micro- and nanoscale. We theoretically analyze the possibility of measuring magnetic fields via the electrical current flowing through quantum dots. We characterize the shot-noise-limited magnetic-field sensitivity of two devices: a single dot in the Coulomb blockade regime, and a double dot in the Pauli blockade regime. Constructing such magnetometers using carbon nanotube quantum dots would benefit from the large, strongly anisotropic and controllable g tensors, the low abundance of nuclear spins, and the small detection volume allowing for nanoscale spatial resolution; we estimate that a sensitivity below 1 μ T/√{Hz} can be achieved with this material. As quantum dots have already proven to be useful as scanning-probe electrometers, our proposal highlights their potential as hybrid sensors having in situ switching capability between electrical and magnetic sensing.

  20. Mechanical Stimulation Enhances Endothelin-1 Hyperalgesia

    PubMed Central

    Joseph, Elizabeth K.; Gear, Robert W.; Levine, Jon D.

    2011-01-01

    When comparing a cumulative dose-response curve for endothelin-1 (ET-1)-induced mechanical hyperalgesia to the effect of individual doses (1 ng, 10 ng, 100 ng and 1 µg) administered in separate groups of rats, a marked difference was observed in the peak magnitude of hyperalgesia. Hyperalgesia was measured as decrease in the threshold for mechanically-induced withdrawal of the hind paw. The cumulative dosing protocol produced markedly greater maximum hyperalgesia. To determine whether this was due to the cumulative dosing protocol or to the repeated exposure to the mechanical test stimulus, we evaluated the impact of repeated testing on ET-1-induced mechanical hyperalgesia. While ET-1-induced mechanical hyperalgesia was dose- and time-dependent, repeated testing of nociceptive threshold, at 5 minute intervals, following a single dose of ET-1, produced further decrease in nociceptive threshold. This mechanical stimulation-induced enhancement of ET-1 hyperalgesia lasted only 3–4 hrs, while the hyperalgesia lasted in excess of 5 days. The stimulation-enhanced hyperalgesia also occurred after a second injection of ET-1, administered 24 hours after the initial dose. That this phenomenon is unique to ET-1 is suggested by the observation that while five additional, direct-acting hyperalgesic agents — PGE2, NGF, GDNF, IL-6 and TNFα — induced robust mechanical hyperalgesia, none produced mechanical stimulation-enhanced hyperalgesia. PMID:21277948

  1. Role of endothelin in the cardiovascular system.

    PubMed

    Rodríguez-Pascual, Fernando; Busnadiego, Oscar; Lagares, David; Lamas, Santiago

    2011-06-01

    The endothelin (ET) system consists of three peptide ligands (ET-1, ET-2 and ET-3) and two G-protein-coupled receptors, ET(A) and ET(B). In the cardiovascular system, ETs, particularly ET-1, are expressed in smooth muscle cells, cardiomyocytes, fibroblasts, and notably in vascular endothelial cells. Intense research over the last 10 years has changed the original view of ET-1 as mainly a vasoconstrictor regulating blood pressure, into a biological factor regulating processes such as vascular remodeling, angiogenesis or extracellular matrix synthesis. The advent of specific (and type-selective) ET receptor antagonists has greatly fostered our knowledge of the biological function of ET-1, and has offered a potential therapeutic approach for numerous diseases including hypertension, atherosclerosis or fibrosis. In this article, we review the regulation of the expression of vascular ET-1, as well as the contribution of ET-1 to endothelial, smooth muscle and fibroblast cell function, with particular interest in the role of ET-1 in the development of cardiovascular diseases.

  2. Endothelin therapeutics in cancer: Where are we?

    PubMed

    Rosanò, Laura; Bagnato, Anna

    2016-03-15

    In human cancers, the autocrine and paracrine loop mediated by the aberrantly activation of endothelin-1 (ET-1) receptor (ET-1R) elicits pleiotropic effects, preferentially mediated by the scaffold protein β-arrestin 1 (β-arr1), on tumor cells and on the host microenvironment, providing a strong rationale for targeting ET-1 receptors. This review describes the most up-to-date preclinical and clinical results obtained by using ET-1 therapeutics. The previous negative clinical results of ET-1 therapeutics should not prevent us from setting the standard of this class of drugs for future well-designed clinical trials. The preclinical data obtained with the dual ETAR and ETBR antagonist macitentan indicate that this molecule, which targets cancer cells and tumor-associated microenvironmental elements, could be a cancer therapeutic option. The field of ET-1 therapeutics will be improved in the next decade, facilitated by the new knowledge on the genomic landscape of the human stroma and tumor, and by the low invasive approaches based on liquid biopsies for the discovery of predictive biomarkers. The information obtained from preclinical studies in patient-derived models and from the Cancer Genome Atlas will set the scene of precision medicine for cancer. Results from these studies are expected to open the possibility that ET-1R antagonists might be more efficacious as molecular cancer therapeutics, able to hamper the functional β-arr1-dependent signaling complexes, either alone or coupled with new targeted approaches.

  3. Endothelin: A novel peptide in the posterior pituitary system

    SciTech Connect

    Yoshizawa, Toshihiro; Kanazawa, Ichiro; Shinmi, Osamu; Kimura, Sadao; Yanagisawa, Masashi; Masaki, Tomoh; Uchiyama, Yasuo ); Giaid, A.; Gibson, S.J.; Polak, J.M. )

    1990-01-26

    Endothelin (ET), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, is present in the porcine spinal cord and may act as a neuropeptide. Endothelin-like immunoreactivity has now been demonstrated by immunohistochemistry in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the pig and the rat. The presence of ET in the porcine hypothalamus was confirmed by reversed-phase high-pressure liquid chromatography and radioimmunoassay. Moreover, in situ hybridization demonstrated ET messenger RNA in porcine paraventricular nuclear neurons. Endothelin-like immunoreactive products in the posterior pituitary of the rat were depleted by water deprivation, suggesting a release of ET under physiological conditions. These findings indicate that ET is synthesized in the posterior pituitary system and may be involved in neurosecretory functions.

  4. INHIBITION OF ENaC BY ENDOTHELIN-1

    PubMed Central

    Sorokin, Andrey; Staruschenko, Alexander

    2016-01-01

    The amiloride-sensitive epithelial Na+ channel (ENaC) is a key player in the regulation of Na+ homeostasis. Its functional activity is under continuous control by a variety of signaling molecules including bioactive peptides of endothelin family. Since ENaC dysfunction is causative for disturbances in total body Na+ levels associated with abnormal regulation of blood volume, blood pressure, and lung fluid balance, the uncovering the molecular mechanisms of inhibitory modulation or inappropriate activation of ENaC is crucial for the successful treatment of a variety of human diseases including hypertension. The precise regulation of ENaC is particularly important for normal Na+ and fluid homeostasis in organs where endothelins are known to act: kidneys, lung and colon. Inhibition of ENaC by endothelin-1 (ET-1) has been established in renal cells and several molecular mechanisms of inhibition of ENaC by ET-1 are proposed and will be reviewed in this chapter. PMID:25817869

  5. Glycinergic inhibition in thalamus revealed by synaptic receptor blockade.

    PubMed

    Ghavanini, Ahmad A; Mathers, David A; Puil, Ernest

    2005-09-01

    Using juvenile rat brain slices, we examined the possibility that strychnine-sensitive receptors for glycine-like amino acids contributed to synaptic inhibition in ventrobasal thalamus, where gamma-aminobutyrate (GABA) is the prevalent inhibitory transmitter. Ventrobasal nuclei showed staining for antibodies against alpha1 and alpha2 subunits of the glycine receptor. Exogenously applied glycine, taurine and beta-alanine increased membrane conductance, effects antagonized by strychnine, indicative of functional glycine receptors. Using glutamate receptor antagonists, we isolated inhibitory postsynaptic potentials and currents (IPSPs and IPSCs) evoked by high-threshold stimulation of medial lemniscus. Like the responses to glycine agonists, these synaptic responses reversed near E(Cl). In comparative tests with GABA receptor antagonists, strychnine attenuated inhibition in a majority of neurons, but did not alter slow, GABA(B) inhibition. For complete blockade, the majority of fast IPSPs required co-application of strychnine with bicuculline or gabazine, GABA(A) receptor antagonists. Strychnine acting with an IC50 approximately = 33 nM, eliminated residual fast inhibition during selective GABA(A) receptor blockade with gabazine. The latency of onset for IPSPs was compatible with polysynaptic pathways or prolonged axonal propagation time. Strychnine lacked effects on monosynaptic, GABAergic IPSPs from zona incerta. The specific actions of strychnine implicated a glycine receptor contribution to fast inhibition in somatosensory thalamus.

  6. Production of endothelin by cultured human endothelial cells following exposure to nicotine or caffeine.

    PubMed

    Lee, W O; Wright, S M

    1999-07-01

    This study evaluated endothelin production by endothelial cells after exposure to nicotine or caffeine. Vasoconstrictive properties have been attributed to both nicotine and caffeine. The presence of endothelin, a potent vasoconstrictor itself, was determined using a radioimmunoassay. The optimal stimulatory doses for nicotine and caffeine were determined to be 1.0 micromol/L and 1.0 mmol/L, respectively. When endothelin production was evaluated over time after exposure to the optimal dose of each agent, it was determined that nicotine stimulated maximum endothelin production within 5 minutes. Caffeine failed to cause a distinct peak of endothelin production within 20 minutes. These results suggest that nicotine may have a possible acute and short-lived effect on the vasoconstrictive response associated with endothelin, while caffeine-induced endothelin release may require more long-term exposure.

  7. Aging and endothelin: determinants of disease.

    PubMed

    Barton, Matthias

    2014-11-24

    Since the beginning of the 20th century human life expectancy has doubled to more than 80 years, and growth and aging of the world population now represent major challenges for healthcare providers, political decision makers, and societies. Cellular senescence is associated with a general, pro-inflammatory state, which represents the common denominator between aging and chronic diseases and their progression. Approaches to interfere with these changes and to allow healthy aging involve modulation of the cellular activity of modifiable molecular mediators (MMMs), such as signaling molecules and growth factors. ET-1 - the biologically predominant member of the endothelin peptide family - is an endothelial cell-derived peptide with a wide variety of developmental and physiological functions, which include embryogenesis, nociception, and natriuresis. In addition, ET-1 is a cytokine-like, multifunctional peptide with pro-inflammatory, mitogenic, and vasoconstrictor properties. If produced in excess amounts ET-1 promotes disease - mainly via activation of its ETA receptor. Because of its multiple disease-promoting functions ET-1 represents an ideal target MMM. Preclinical studies targeting either activity or production of ET-1 - utilizing ERAs, ARBs, or ACEIs, respectively - have demonstrated that partial regression of aging-associated changes in vasculature and kidney is possible. In this article I will review the molecular regulation of ET-1 and its role in the physiology of vascular homeostasis, aging, and cellular senescence. The clinical implications of activators of ET-1 overproduction, modalities for delaying or reversing aging-related cellular changes, as well as interventions to promote healthy aging and early disease prevention - particularly physical activity - are discussed.

  8. Endothelin, a peptide inhibitor of Na(+)-K(+)-ATPase in intact renaltubular epithelial cells

    SciTech Connect

    Zeidel, M.L.; Brady, H.R.; Kone, B.C.; Gullans, S.R. )

    1989-12-01

    Endothelin, a potent vasoconstrictor released by vascular endothelial cells, can induce natriuresis in vivo. These studies examined the regulation of Na+ transport by endothelin in suspensions of rabbit proximal tubule (PT) and inner medullary collecting duct (IMCD) cells. Endothelin reduced oxygen consumption (QO2) by 18 +/- 1% in IMCD cells but did not alter QO2 in PT cells. In IMCD cells, endothelin inhibited QO2 half maximally at approximately 5 x 10(-12) M. Several lines of evidence indicate that endothelin reduces QO2 by inhibiting the Na(+)-K(+)-ATPase. (1) Endothelin gave no further inhibition of QO2 after ouabain and blunted the stimulatory effect of amphotericin B on QO2 (+29 +/- 4% in absence of endothelin, 0 +/- 5% in presence of endothelin; n = 6 preparations, P less than 0.001). (2) Endothelin inhibited ouabain-sensitive 86Rb+ uptake by 46.6 +/- 8.6% at 10 s and by 35.4 +/- 5.3% at 30 s without altering uptake at (60 min. 3) Addition of endothelin to IMCD cells induced a net K+ efflux with an initial rate of 32.2 +/- 4.8 nmol.min-1.mg protein-1, consistent with inhibition of the Na(+)-K(+)-ATPase. In contrast to the response observed in intact cells, in permeabilized IMCD cells endothelin did not inhibit ouabain-sensitive ATPase. Several observations indicated that prostaglandin E2 (PGE2) mediates endothelin inhibition of Na(+)-K(+)-ATPase activity. (1) The response to endothelin was blocked by ibuprofen in assays of QO2, net K+ flux, and 86Rb+ uptake. (2) Endothelin and PGE2 gave equivalent, nonadditive inhibition of ouabain-sensitive 86Rb+ uptake.

  9. Expression of endothelin receptors in frog, chicken, mouse and human pigment cells.

    PubMed

    Scarparo, Ana Cristina; Isoldi, Mauro César; de Lima, Leonardo Henrique Ribeiro Graciani; Visconti, Maria Aparecida; Castrucci, Ana Maria de Lauro

    2007-07-01

    Several reports have shown the participation of vasoactive endothelins (ETs) in the regulation of vertebrate pigment cells. In the present study, we identified ET receptors in pigment cells of vertebrate species by RT-PCR assays, and compared the differential expression of the various subtypes in each species by quantitative PCR. RT-PCR was performed with specific primers for ETC, ETA(X) or ETA in Xenopus laevis melanophores, ETA or ETB(2) in chicken melanocytes, ETA or ETB in murine (B-16, S-91 or Melan-A) or human (SK-Mel 23 or SK-Mel 28) melanoma cells, and the products obtained were confirmed by cloning and sequencing. The results showed the presence of ETA(X), but not ETA mRNA, and confirmed the expression of ETC in X. laevis melanophores. ETA and ETB(2) mRNAs were also demonstrated in chicken melanocytes. ETA and ETB receptor were identified in S-91, B16 and Melan-A murine cells. In human melanoma cells, SK-Mel 23 and SK-Mel 28, we confirmed the presence of ETB mRNA, and also found ETA mRNA. The comparison between the two subtypes present in the pigment cell of each species and among species demonstrated that the expression of ETAs in chicken, mouse, and human melanocytes is negligible, as is the expression of ETA(X) in Xenopus melanophores. The relative expression, as determined by quantitative PCR, was as follows: chicken ETB>SK-Mel 23 ETB>S91 ETB>Xenopus ETC, suggesting that the endothelin system plays a major role in avian and mammalian pigment cell regulation, as compared to lower vertebrates. The phylogenetic analysis revealed that subtype A receptors were probably the most primitive ET receptors, directly deriving from the ancestral type; all the other receptors, B subtypes and C, originated from diverse derivative molecules.

  10. β-Arrestin-1 Drives Endothelin-1–Mediated Podocyte Activation and Sustains Renal Injury

    PubMed Central

    Buelli, Simona; Rosanò, Laura; Gagliardini, Elena; Corna, Daniela; Longaretti, Lorena; Pezzotta, Anna; Perico, Luca; Conti, Sara; Rizzo, Paola; Novelli, Rubina; Morigi, Marina; Zoja, Carlamaria; Remuzzi, Giuseppe; Bagnato, Anna

    2014-01-01

    Activation of endothelin-A receptor (ETAR) by endothelin-1 (ET-1) drives epithelial-to-mesenchymal transition in ovarian tumor cells through β-arrestin signaling. Here, we investigated whether this pathogenetic pathway could affect podocyte phenotype in proliferative glomerular disorders. In cultured mouse podocytes, ET-1 caused loss of the podocyte differentiation marker synaptopodin and acquisition of the mesenchymal marker α-smooth muscle actin. ET-1 promoted podocyte migration via ETAR activation and increased β-arrestin-1 expression. Activated ETAR recruited β-arrestin-1 to form a trimeric complex with Src leading to epithelial growth factor receptor (EGFR) transactivation and β-catenin phosphorylation, which promoted gene transcription of Snail. Increased Snail expression fostered ET-1–induced migration as confirmed by Snail knockdown experiments. Silencing of β-arrestin-1 prevented podocyte phenotypic changes and motility and inhibited ETAR-driven signaling. In vitro findings were confirmed in doxorubicin (Adriamycin)-induced nephropathy. Mice receiving Adriamycin developed renal injury with loss of podocytes and hyperplastic lesion formation; β-arrestin-1 expression increased in visceral podocytes and in podocytes entrapped in pseudo-crescents. Administration of the selective ETAR antagonist sitaxsentan prevented podocyte loss, formation of the hyperplastic lesions, and normalized expression of glomerular β-arrestin-1 and Snail. Increased β-arrestin-1 levels in podocytes retrieved from crescents of patients with proliferative glomerulopathies confirmed the translational relevance of these findings and suggest the therapeutic potential of ETAR antagonism for a group of diseases still needing a specific treatment. PMID:24371298

  11. Expression of endothelin in equine laminitis.

    PubMed

    Katwa, L C; Johnson, P J; Ganjam, V K; Kreeger, J M; Messer, N T

    1999-05-01

    Biosynthesis of endothelin-1 (ET-1), the most potent endogenous vasoconstrictor yet identified, is increased following myocardial infarction (MI) in man. Pathological events which occur in the connective tissues of the equine hoof during laminitis are similar in some respects, to changes occurring in the myocardial connective tissues following MI in man. The objective of this study was to determine whether ET-1 expression in connective tissues obtained from the hoof of laminitic horses is increased compared with tissues obtained from healthy horses. Expression of ET-1 in connective tissues of the equine hoof was measured following tissue extraction from 3 groups of horses: horses in which acute laminitis had been induced by the administration of starch; chronically foundered horses; nonlaminitic horses. The concentration of ET-1 in laminar connective tissues obtained from all laminitic horses (1573.0 +/- 392.8 pg/g of tissue; n = 10) was increased when compared with tissues obtained from nonlaminitic horses (392.5 +/- 117.4 pg/g of tissue; n = 5) (P<0.05). The concentration of ET-1 in laminar connective tissues obtained from the experimentally induced, acute laminitic horses (1043.6 +/- 254.4 pg/g of tissue; n = 7) and from the spontaneously affected, chronic laminitic horses (2808.3 +/- 878.6 pg/g of tissue; n = 3) was increased compared with the control group (P<0.05, P<0.01, respectively). The concentration of ET-1 in laminar connective tissues obtained from the chronic laminitic horses was greater than that of the experimentally induced, acute laminitic group (P<0.05). It is suggested that the data provide a strong argument that increased ET-1 expression in the connective tissues of the equine hoof represent a potentially important and hitherto unrecognised component of the pathophysiology of equine laminitis. Further studies are needed to determine whether inhibitors of ET-1 converting enzyme or antagonists of ET-1 receptors might be useful in the treatment

  12. Celecoxib offsets the negative renal influences of cyclosporine via modulation of the TGF-β1/IL-2/COX-2/endothelin ET{sub B} receptor cascade

    SciTech Connect

    El-Gowelli, Hanan M.; Helmy, Maged W.; Ali, Rabab M.; El-Mas, Mahmoud M.

    2014-03-01

    Endothelin (ET) signaling provokes nephrotoxicity induced by the immunosuppressant drug cyclosporine A (CSA). We tested the hypotheses that (i): celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, counterbalances renal derangements caused by CSA in rats and (ii) the COX-2/endothelin ET{sub B} receptor signaling mediates the CSA-celecoxib interaction. Ten-day treatment with CSA (20 mg/kg/day) significantly increased biochemical indices of renal function (serum urea, creatinine), inflammation (interleukin-2, IL-2) and fibrosis (transforming growth factor-β{sub 1}, TGF-β{sub 1}). Histologically, CSA caused renal tubular atrophy along with interstitial fibrosis. These detrimental renal effects of CSA were largely reduced in rats treated concurrently with celecoxib (10 mg/kg/day). We also report that cortical glomerular and medullary tubular protein expressions of COX-2 and ET{sub B} receptors were reduced by CSA and restored to near-control values in rats treated simultaneously with celecoxib. The importance of ET{sub B} receptors in renal control and in the CSA-celecoxib interaction was further verified by the findings (i) most of the adverse biochemical, inflammatory, and histopathological profiles of CSA were replicated in rats treated with the endothelin ET{sub B} receptor antagonist BQ788 (0.1 mg/kg/day, 10 days), and (ii) the BQ788 effects, like those of CSA, were alleviated in rats treated concurrently with celecoxib. Together, the data suggest that the facilitation of the interplay between the TGF-β1/IL-2/COX-2 pathway and the endothelin ET{sub B} receptors constitutes the cellular mechanism by which celecoxib ameliorates the nephrotoxic manifestations of CSA in rats. - Highlights: • Celecoxib abolishes nephrotoxic manifestations of CSA in rats. • Blockade of ETB receptors by BQ788 mimicked the nephrotoxic effects of CSA. • CSA or BQ788 reduces renal protein expression of COX-2 and endothelin ETB receptors. • Enhanced TGFβ1/IL-2/COX2/ETB

  13. Interactions between endothelin-1 and atrial natriuretic peptide influence cultured chick cardiac myocyte contractility.

    PubMed

    Bézie, Y; Mesnard, L; Longrois, D; Samson, F; Perret, C; Mercadier, J J; Laurent, S

    1996-09-12

    We have previously shown that rat atrial natriuretic peptide (ANP) reduces the contractility of cultured, spontaneously beating chick embryo ventricular cells, an effect opposite to that of endothelin-1. Endothelin-1 has been described as a secretagogue for natriuretic peptides in vitro and in vivo. Natriuretic peptides can inhibit endothelin-1 secretion from cultured endothelial cells, suggesting a negative feedback mechanism between endothelial cells and cardiomyocytes. The aim of this study was to determine whether ANP attenuated the endothelin-1-induced increase in myocyte contractility. Using a video-microscopy system we studied the contractility of isolated cultured chick ventricular myocytes in response to endothelin-1, chicken natriuretic peptide (ChNP), and both. We also used Northern blot analysis to study the time course of ChNP expression in response to endothelin-1. Endothelin-1 (10(-8) M) increased chick cardiomyocyte contractility by 20-25% between 5 and 15 min (P < 0.05). Although ChNP (3 x 10(-7) M) did not significantly change the amplitude of contraction in basal conditions, it prevented the endothelin-1-induced increase in contractility (P < 0.05) when perfused prior to endothelin-1, and reversed it when perfused 5 min after endothelin-1 exposure (P < 0.05). Endothelin-1 significantly increased the accumulation of ChNP mRNA in chick ventricular myocytes as early as the 30 min after exposure (P < 0.05), with a maximal effect after 2 h of stimulation (P < 0.01); no effect was observed after 4 h. These data support an interaction between endothelin-1 and natriuretic peptides as autocrine/paracrine factors regulating the contractile function of chick cardiac myocytes, as well as their antagonistic effects on cardiac cell contractility. The early and transient expression of ChNP mRNA in response to endothelin-1 may be involved in this interaction.

  14. Endothelin-1 receptor antagonist: effects on endothelin- and cyclosporine-treated mesangial cells.

    PubMed

    Takeda, M; Breyer, M D; Noland, T D; Homma, T; Hoover, R L; Inagami, T; Kon, V

    1992-06-01

    Endothelin-1 (Et) has profound effects on glomerular microcirculation and mesangial cell contraction. A parameter of mesangial cell contraction was examined by measuring myosin light chain phosphorylation (MLCP) in glomerular mesangial cells in the presence and absence of a newly developed endothelin-1 receptor antagonist (EtA). Addition of Et alone (10 nM) caused a marked increase in MLCP, which, on average, rose by 53 +/- 6% above the level in cells exposed to vehicle (P less than 0.0005). This effect was shown to continue for at least one hour; MLCP at 60 minutes was 64 +/- 12% higher than controls, (P less than 0.025), constituting a unique observation of an in vitro parameter which parallels the characteristic in vivo effect of Et. Treatment of cells with EtA virtually abolished this Et-induced increase in MLCP, which rose by only 2 +/- 3% and -1 +/- 4% for doses of EtA of 44 nM and 66 nM, respectively. Examination of the intracellular calcium concentration, [Ca2+]i, revealed that EtA almost completely abolished the transient increase in [Ca2+]i evoked by Et and also suppressed the early portions of the sustained increase in [Ca2+]i. EtA was ineffective in abolishing [Ca2+]i increase in response to arginine vasopressin. Finally, to evaluate EtA's efficacy in a pathophysiologic setting, we also studied mesangial cells exposed to cyclosporine (Cs). Exposure of mesangial cells to Cs (10(-5) M) for 60 minutes caused a significant increase in MLCP, on average, by 38 +/- 6% above control (P less than 0.0005), while cells exposed to Cs in the presence of EtA increased MLCP significantly less, by only 15 +/- 9%. These data provide further evidence for Et's long-lasting cellular actions, and demonstrate inhibitory effects of an Et receptor antagonist after direct cellular exposure to Et and also after Cs exposure, a pathophysiologic setting which likely involves Et.

  15. Transforming growth factor-beta induces endothelin-1 expression through activation of the Smad signaling pathway.

    PubMed

    Rodríguez-Pascual, Fernando; Reimunde, Francisco Manuel; Redondo-Horcajo, Mariano; Lamas, Santiago

    2004-11-01

    Expression of the endothelin-1 gene is subject to complex regulation by different factors, among which transforming growth factor-beta is one of the most important. We have analyzed the mechanism by which transforming growth factor-beta increases endothelin-1 expression in vascular endothelial cells. Transcriptional activation of the endothelin-1 promoter accounted for the transforming growth factor-beta-induced increase in endothelin-1 mRNA levels. Two DNA elements within the promoter are responsible for this effect: a Smad binding element and a proximal activator protein-1 site. Mutation of both elements abolished transforming growth factor-beta responsiveness. Overexpression of the Smad3 isoform strongly potentiates transforming growth factor-beta- induced endothelin-1 promoter activity in a phosphorylation-dependent manner. These results demonstrate that transforming growth factor-beta induces endothelin-1 expression by a functional cooperation between Smads and activator protein-1 through activation of the Smad signaling pathway.

  16. Higher endothelin concentrations in the fetoplacental unit of pregnant women of African ancestry.

    PubMed

    Carbonne, B; Mignot, T M; Papiernik, E; Ferré, F

    1998-03-01

    Immunoreactive endothelin was assayed in maternal and fetal biologic fluids of women of African and European ancestry with normal singleton pregnancies undergoing cesarean section at term for obstetric reasons. Endothelin concentration was found to be higher in the umbilical vein and artery blood of women of African origin. Higher production of endothelins in the fetoplacental unit may place these women at a greater risk of preeclampsia.

  17. Endothelin receptors in rat liver: lipocytes as a contractile target for endothelin 1.

    PubMed Central

    Housset, C; Rockey, D C; Bissell, D M

    1993-01-01

    The endothelins (ETs) form a group of three vasoactive peptides (ET-1, ET-2, and ET-3) for which two types of cellular receptors have been identified, types A and B ET receptors (ETA and ETB receptors, respectively). To address possible targets for ETs within the liver, we isolated the four principal liver cell populations and placed them in short-term primary culture. By ligand-binding assay and mRNA levels, expression of ET receptors was greatest on hepatic lipocytes (Ito cells or fat-storing cells), which are perisinusoidal cells exhibiting features of smooth muscle cells. Moreover, lipocytes expressed both ETA and ETB receptors. The mRNA for ETB receptor, but not for ETA receptor, was detectable in sinusoidal endothelial cells and Kupffer cells; neither mRNA was detectable in hepatocytes. Both ET-1 and ET-3 elicited contraction of activated lipocytes cultured on collagen lattices; the EC50 value for ET-1 was 3 +/- 1 nM and for ET-3 was 17 +/- 12 nM. In cell isolates from injured liver (after administration of carbon tetrachloride), expression of ET receptors was unchanged. However, mRNA for ET-1 was significantly increased in activated lipocytes, suggesting an autocrine loop for the initiation of lipocyte contraction. The findings imply that ET-1 may play a role in regulating sinusoidal perfusion through its effect on lipocytes, particularly in injury states. Images Fig. 3 Fig. 4 PMID:8415690

  18. Alpha-adrenergic receptor blockade by phentolamine increases the efficacy of vasodilators in penile corpus cavernosum.

    PubMed

    Kim, N N; Goldstein, I; Moreland, R B; Traish, A M

    2000-03-01

    Penile trabecular smooth muscle tone, a major determinant of erectile function, is highly regulated by numerous inter- and intracellular pathways. The interaction between pathways mediating contraction and relaxation has not been studied in detail. To this end, we investigated the functional effects of alpha adrenergic receptor blockade with phentolamine and its interaction with vasodilators (sildenafil, vasoactive intestinal polypeptide (VIP) and PGE1) that elevate cyclic nucleotides on penile cavernosal smooth muscle contractility. In organ bath preparations of cavernosal tissue strips contracted with phenylephrine, phentolamine significantly enhanced relaxation induced by sildenafil, VIP and PGE1. Sildenafil, VIP or PGE1 also significantly enhanced relaxation induced by phentolamine in cavernosal tissue strips contracted with phenylephrine. To study the effects of alpha adrenergic receptor blockade and modification of cyclic nucleotide metabolism during active neurogenic input, cavernosal tissue strips in organ bath preparations were contracted with the non-adrenergic agonist endothelin-1 and subjected to electrical field stimulation (EFS) in the absence or presence of phentolamine and/or sildenafil. EFS (5-40Hz) typically caused biphasic relaxation and contraction responses. Phentolamine alone enhanced relaxation and reduced or prevented contraction to EFS. Sildenafil enhanced relaxation to EFS at lower frequencies (< or = 5 Hz). The combination of phentolamine and sildenafil enhanced EFS-induced relaxation at all frequencies tested. EFS, in the presence of 10 nM phentolamine and 30 nM sildenafil, produced enhanced relaxation responses which were quantitatively similar to those obtained in the presence of 50 nM sildenafil alone. Thus, blockade of alpha-adrenergic receptors with phentolamine increases the efficacy of cyclic nucleotide-dependent vasodilators. Furthermore, phentolamine potentiates relaxation and attenuates contraction in response to endogenous

  19. Role of endothelin in uteroplacental circulation and fetal vascular function.

    PubMed

    Paradis, Alexandra; Zhang, Lubo

    2013-09-01

    Endothelins are 21-amino acid peptides involved in vascular homeostasis. Three types of peptide have been identified, with endothelin-1 (ET-1) being the most potent vasoconstrictor currently known. Two endothelin receptor subtypes are found in various tissues, including the brain, heart, blood vessel, lung, and placenta. The ETA-receptor is associated with vasoconstriction in vascular smooth muscle. Conversely, the ETB-receptor can elicit a vasoconstrictor effect in vascular smooth muscle and a vasodilator effect via its action in endothelial cells. Both receptors play a key role in maintaining circulatory homeostasis and vascular function. Changes in ET-1 expression are found in various disease states, and overexpression of ET-1 is observed in hypertension and preeclampsia in pregnancy. Placental localization of ET-1 implies a key role in regulating the uteroplacental circulation. Additionally, ET-1 is important in the fetal circulation and is involved in the pulmonary circulation and closure of the ductus arteriosus after birth, as well as fetal growth constriction in utero. ET receptor antagonists and nitric oxide donors may provide therapeutic potential in treating conditions associated with overexpression of ET and hypertension.

  20. Human cultured endothelial cells do secrete endothelin-1

    SciTech Connect

    Clozel, M.; Fischli, W. )

    1989-01-01

    Endothelin-1 (ET-1) has been identified in the conditioned medium of porcine endothelial cells. Human endothelin (ET-1) cloned from a placenta cDNA library is similar to porcine, but it is not known whether endothelin itself is secreted by human endothelial cells. To answer this question, a conditioned medium taken every 48 h from confluent cultures of umbilical vein endothelial cells was analyzed by HPLC and all fractions were tested for their ability to inhibit ({sup 125}I)ET-1 binding on human placenta membranes. Only one fraction did inhibit ({sup 125}I)ET-1 binding. When the conditioned medium was spiked with ET-1, the same single fraction inhibited ({sup 125}I)ET-1 binding showing that ET-1, itself, is present in the conditioned medium of human endothelial cells. ET-1 accumulates with time, reaching a plateau at 48 h. ET-1 secretion is not increased by a 24-h incubation of endothelial cells with phorbol myristate acetate, interleukin-1, tumor necrosis factor, thrombin or neuropeptide Y.

  1. Vasodilator responses and endothelin-dependent vasoconstriction in metabolically healthy obesity and the metabolic syndrome

    PubMed Central

    Schinzari, Francesca; Iantorno, Micaela; Campia, Umberto; Mores, Nadia; Rovella, Valentina; Tesauro, Manfredi; Di Daniele, Nicola

    2015-01-01

    Patients with metabolically healthy obesity (MHO) do not present the cluster of metabolic abnormalities that define the metabolic syndrome (MetS). Whether MHO is associated with lower impairment of vasoreactivity than the MetS is unknown. For this purpose, forearm blood flow (FBF) responses were measured by strain-gauge plethysmography during the intra-arterial infusion of acetylcholine (ACh), sodium nitroprusside (SNP), and/or the selective endothelin type A (ETA) receptor blocker BQ-123 in 119 obese individuals with MHO (n = 34) or with the MetS (n = 85) and in healthy lean controls (n = 56). ACh and SNP caused a significant vasodilation in both obese and lean participants (all P < 0.001). However, the response to both agents was significantly lower in the obese than in the control group (both P < 0.001). Among the obese participants, the reactivity to ACh was higher in MHO than in MetS patients, whereas the responsiveness to SNP was equally impaired in both groups (P = 0.45). Infusion of BQ-123 significantly increased FBF in obese patients (P < 0001), but not in the lean participants; hence, FBF following ETA receptor blockade was higher in both obese groups than in controls (both P < 0.001). FBF response to BQ-123 was significantly higher in patients with the MetS than in those with MHO (P = 0.007). In conclusion, patients with MHO have abnormal vascular reactivity, although their endothelial dysfunction is less pronounced than in patients with the MetS. These findings indicate that obesity is associated with vascular damage independent of those metabolic abnormalities underlying the MetS. PMID:26374766

  2. Flow regulation of endothelin-1 production in the inner medullary collecting duct.

    PubMed

    Pandit, Meghana M; Inscho, Edward W; Zhang, Shali; Seki, Tsugio; Rohatgi, Rajeev; Gusella, Luca; Kishore, Bellamkonda; Kohan, Donald E

    2015-03-15

    Collecting duct-derived endothelin (ET)-1 is an autocrine inhibitor of Na(+) and water reabsorption; its deficiency causes hypertension and water retention. Extracellular fluid volume expansion increases collecting duct ET-1, thereby promoting natriuresis and diuresis; however, how this coupling between volume expansion and collecting duct ET-1 occurs is incompletely understood. One possibility is that volume expansion increases tubular fluid flow. To investigate this, cultured IMCD3 cells were subjected to static or flow conditions. Exposure to a shear stress of 2 dyn/cm(2) for 2 h increased ET-1 mRNA content by ∼2.3-fold. Absence of perfusate Ca(2+), chelation of intracellular Ca(2+), or inhibition of Ca(2+) signaling (calmodulin, Ca(2+)/calmodulin-dependent kinase, calcineurin, PKC, or phospholipase C) prevented the flow response. Evaluation of possible flow-activated Ca(2+) entry pathways revealed no role for transient receptor potential (TRP)C3, TRPC6, and TRPV4; however, cells with TRPP2 (polycystin-2) knockdown had no ET-1 flow response. Flow increased intracellular Ca(2+) was blunted in TRPP2 knockdown cells. Nonspecific blockade of P2 receptors, as well as specific inhibition of P2X7 and P2Y2 receptors, prevented the ET-1 flow response. The ET-1 flow response was not affected by inhibition of either epithelial Na(+) channels or the mitochondrial Na(+)/Ca(2+) exchanger. Taken together, these findings provide evidence that in IMCD3 cells, flow, via polycystin-2 and P2 receptors, engages Ca(2+)-dependent signaling pathways that stimulate ET-1 synthesis.

  3. Requirement of cortical actin organization for bombesin, endothelin, and EGF receptor internalization.

    PubMed

    Lunn, J A; Wong, H; Rozengurt, E; Walsh, J H

    2000-12-01

    The role of actin organization in occupancy-induced receptor internalization remains poorly defined. Here we report that treatment of mouse Swiss 3T3 cells with latrunculin A, a potent inhibitor of actin polymerization (including cortical actin), inhibited the internalization of the endogenous bombesin/gastrin-releasing peptide (GRP) receptor, as judged by uptake of (125)I-labeled GRP or fluorescent Cy3-labeled bombesin. In contrast, cells pretreated with cytochalasin D showed minimal inhibition of bombesin/GRP receptor internalization. Similarly, pretreatment of Swiss 3T3 cells with the potent Rho-kinase inhibitor HA-1077, at concentrations (10-20 microM) that abrogated bombesin-mediated stress fiber formation, did not significantly alter receptor-mediated internalization of (125)I-GRP. These results indicate that bombesin/GRP receptor internalization depends on latrunculin A-sensitive cortical actin rather than on rapidly turning over actin stress fibers that are disrupted by either cytochalasin D or HA-1077. The rates and total levels of internalization of the endogenously expressed endothelin A receptor and epidermal growth factor receptor were also markedly reduced by latrunculin A in Swiss 3T3 cells. The potency of latrunculin A for inhibiting G protein-coupled receptor endocytosis was comparable to that for reducing internalization of the epidermal growth factor tyrosine kinase receptor. We conclude that cortical actin structures, disrupted by latrunculin A, are necessary for occupancy-induced receptor internalization in animal cells.

  4. The response of the lamb ductus arteriosus to endothelin: developmental changes and influence of light.

    PubMed

    Coceani, Flavio; Kelsey, Lois; Seidlitz, Eric

    2002-07-26

    Endothelin-1 (ET-1) is a putative messenger of oxygen in the ductus arteriosus. Since the ability of the vessel to contract to oxygen increases with gestation, we wished to ascertain whether ET-1 action is also developmentally regulated. A corollary objective was to assess whether any gestational variation in the ET-1 contraction is due to a change in the ET(A)-mediated action or to a shift in the balance between opposing, contractile (ET(A) - mediated) and relaxant (ET(B)-mediated), actions. Experiments were performed with isolated ductal strips from preterm (0.7 gestation) and near-term fetal lambs. ET-1 contracted the ductus dose-dependently (10(-10)-10(-7) M) at both ages; however, the peak contraction was about double in magnitude at term. Regardless of age, ET-1 contraction was greater with preparations kept in the dark compared to those exposed to light. This effect of light was not seen after removing the endothelium or when treating the intact tissue with the ET(B) antagonist BQ788 (1 microM). In the dark, however, BQ788 did not modify significantly the ET-1 response at either age. We conclude that ET-1 becomes a stronger ductus constrictor with fetal age, conceivably by acting on ET(A) receptors. Hence, the concept of ET-1 mediating the oxygen contraction is further validated. Peculiarly, the ET-1 contraction is curtailed by light through a hitherto undefined ET(B) receptor-linked process.

  5. Phosphoramidon blocks big-endothelin-1 but not endothelin-1 enhancement of vascular permeability in the rat.

    PubMed Central

    Lehoux, S.; Plante, G. E.; Sirois, M. G.; Sirois, P.; D'Orléans-Juste, P.

    1992-01-01

    1. Changes in vascular permeability following intravenous injections of human big-endothelin-1 (big-ET-1) and endothelin-1 (ET-1) were measured by extravasation of Evans blue dye (EB, 20 mg kg-1) in selected tissues. 2. A low dose of big-ET-1 (40 pmol kg-1) failed to alter vascular permeability but a dose of 400 pmol kg-1 increased EB extravasation in the trachea, upper and lower bronchi, and lung parenchyma by 55 to 69% (P < 0.05). Vascular permeability was also enhanced in the liver, spleen, kidney, heart, and diaphragm by 20, 14, 41, 25, and 67%, respectively (P < 0.05). 3. Upon injection of ET-1 (400 pmol kg-1), EB extravasation increased in the upper and lower bronchi, lung parenchyma, liver, pancreas, kidney, heart, and diaphragm. 4. Administration of ET-1 and big-ET-1 was not associated with significant systemic responses. 5. Pretreatment with phosphoramidon (PA) blocked the response to big-ET-1 in all tissues examined but this inhibitor failed to alter the response to ET-1. 6. We conclude from these results that the dose-dependent increase in vascular permeability induced by big-ET-1 in various tissues follows its conversion to ET-1 by the endothelin converting enzyme, a PA-sensitive process. PMID:1467845

  6. Biosynthesis and modulation of endothelin from bovine pulmonary arterial endothelial cells.

    PubMed

    Ohlstein, E H; Arleth, A; Ezekiel, M; Horohonich, S; Ator, M A; Caltabiano, M M; Sung, C P

    1990-01-01

    The biosynthesis and modulation of the vasoconstrictor peptide endothelin was studied in the conditioned medium from cultured bovine pulmonary artery endothelial (BPAE) cells. Conditioned medium from cultured BPAE cells produced contraction of isolated rabbit aortic rings. Incubation of BPAE cells with the protease inhibitors TPCK or isatoic anhydride attenuated the extent of conditioned medium-induced contractions. Incubation of BPAE cells with thrombin produced an enhancement of conditioned medium-induced contraction by approximately 25%. Endothelin levels in conditioned medium were measured by RIA and incubation of BPAE cells with TPCK or isatoic anhydride significantly reduced endothelin levels, whereas incubation with thrombin or transforming growth factor beta-1 stimulated the levels of endothelin in the conditioned medium. These data indicate that endothelin may be modulated by certain protease inhibitors and by platelet and immune cell mediators and suggest a potential new mode of vascular tone regulation.

  7. High glucose-induced, endothelin-dependent fibronectin synthesis is mediated via NF-kappa B and AP-1.

    PubMed

    Chen, Shali; Mukherjee, Suranjana; Chakraborty, Chandan; Chakrabarti, Subrata

    2003-02-01

    Human endothelial cells cultured under high glucose (HG) conditions were shown before to upregulate several basement membrane proteins, including fibronectin (FN), thus mimicking effects of diabetes. Using human macrovascular (HUVEC) and microvascular (HMEC) endothelial cell lines, we evaluated in the present study some of the key molecular signaling events involved in HG-induced FN overexpression. This expression was shown to be dependent on endogenous endothelin (ET) receptor-mediated signaling. We also examined the roles played by protein kinase C (PKC) and the transcription factors nuclear factor kappaB (NF-kappaB) and activating protein (AP)-1 with respect to such changes. HG, PKC activators, and ETs (ET-1 and ET-3) that increased FN expression also caused activation of NF-kappaB and AP-1. Inhibitors of both NF-kappaB and AP-1 prevented HG- and ET-induced FN production. ET receptor blockade also prevented these HG- and ET-mediated changes. The results of this study indicate that glucose-induced increased FN production in diabetes may be mediated via ET-dependent NF-kappaB and AP-1 activation.

  8. Endothelin stimulates phospholipase C, Na+/H+ exchange, c-fos expression, and mitogenesis in rat mesangial cells.

    PubMed Central

    Simonson, M S; Wann, S; Mené, P; Dubyak, G R; Kester, M; Nakazato, Y; Sedor, J R; Dunn, M J

    1989-01-01

    A recently described peptide hormone, endothelin, is a potent vasoconstrictor, but it is unclear whether endothelin has other biological actions. These experiments extend the range of biological actions of endothelin to stimulation of mitogenesis. Endothelin at low concentrations (0.1-10 nM) induced mitogenesis by quiescent rat glomerular mesangial cells in culture. Mitogenesis induced by endothelin was accompanied by activation of phospholipase C with increased inositol phosphate turnover and increments of intracellular [Ca2+]. Endothelin also activated Na+/H+ exchange, causing cytosolic alkalinization, and enhanced transcription of the c-fos protooncogene, additional biochemical signals closely linked to proliferation. In addition to being a vasoconstrictor, endothelin thus also functions as a mitogen, presumably through activation of phospholipase C. Images PMID:2536405

  9. The human endothelin family: three structurally and pharmacologically distinct isopeptides predicted by three separate genes.

    PubMed Central

    Inoue, A; Yanagisawa, M; Kimura, S; Kasuya, Y; Miyauchi, T; Goto, K; Masaki, T

    1989-01-01

    Three distinct human endothelin-related genes were cloned by screening a genomic DNA library under a low hybridization stringency with a synthetic oligonucleotide probe encoding a portion of the endothelin sequence. Genomic Southern blot analysis with the same oligonucleotide probe showed three corresponding chromosomal loci not only in the human genome but also in porcine and rat genomes. The nucleotide sequences of the three human genes were highly conserved within the regions encoding the 21-residue (mature) endothelins, in spite of the fact that the immediately upstream exon sequences, which encode a part of the propeptides, retained little similarity. Moreover, each of the human genes predicted a putative 21-residue peptide, similar to but distinct from each other: (i) the "classical" endothelin (ET-1), (ii) [Trp6,Leu7]endothelin (ET-2), and (iii) [Thr2,Phe4,Thr5,Tyr6, Lys7,Tyr14]endothelin (ET-3). Synthetic ET-1, ET-2, and ET-3 were prepared according to the deduced amino acid sequences, and the biological activities were assayed by contraction of isolated porcine coronary artery strips and by intravenous injection to anesthetized rats. All these synthetic peptides produced strong vasoconstrictor and pressor responses. However, the quantitative profiles of the pharmacological activities were considerably different among the three isopeptides, suggesting the possible existence of endothelin receptor subtypes. Images PMID:2649896

  10. Endothelin uncouples gap junctions in sustentacular cells and olfactory ensheathing cells of the olfactory mucosa.

    PubMed

    Le Bourhis, Mikaël; Rimbaud, Stéphanie; Grebert, Denise; Congar, Patrice; Meunier, Nicolas

    2014-09-01

    Several factors modulate the first step of odour detection in the rat olfactory mucosa (OM). Among others, vasoactive peptides such as endothelin might play multifaceted roles in the different OM cells. Like their counterparts in the central nervous system, the olfactory sensory neurons are encompassed by different glial-like non-neuronal OM cells; sustentacular cells (SCs) surround their cell bodies, whereas olfactory ensheathing cells (OECs) wrap their axons. Whereas SCs maintain both the structural and ionic integrity of the OM, OECs assure protection, local blood flow control and guiding of olfactory sensory neuron axons toward the olfactory bulb. We previously showed that these non-neuronal OM cells are particularly responsive to endothelin in vitro. Here, we confirmed that the endothelin system is strongly expressed in the OM using in situ hybridization. We then further explored the effects of endothelin on SCs and OECs using electrophysiological recordings and calcium imaging approaches on both in vitro and ex vivo OM preparations. Endothelin induced both robust calcium signals and gap junction uncoupling in both types of cells. This latter effect was mimicked by carbenoxolone, a known gap junction uncoupling agent. However, although endothelin is known for its antiapoptotic effect in the OM, the uncoupling of gap junctions by carbenoxolone was not sufficient to limit the cellular death induced by serum deprivation in OM primary culture. The functional consequence of the endothelin 1-induced reduction of the gap junctional communication between OM non-neuronal cells thus remains to be elucidated.

  11. Thromboxane prostanoid receptors enhance contractions, endothelin-1, and oxidative stress in microvessels from mice with chronic kidney disease.

    PubMed

    Wang, Cheng; Luo, Zaiming; Kohan, Donald; Wellstein, Anton; Jose, Pedro A; Welch, William J; Wilcox, Christopher S; Wang, Dan

    2015-05-01

    Cardiovascular disease is frequent in chronic kidney disease and has been related to angiotensin II, endothelin-1 (ET-1), thromboxane A2, and reactive oxygen species (ROS). Because activation of thromboxane prostanoid receptors (TP-Rs) can generate ROS, which can generate ET-1, we tested the hypothesis that chronic kidney disease induces cyclooxygenase-2 whose products activate TP-Rs to enhance ET-1 and ROS generation and contractions. Mesenteric resistance arterioles were isolated from C57/BL6 or TP-R+/+ and TP-R-/- mice 3 months after SHAM-operation (SHAM) or surgical reduced renal mass (RRM, n=6/group). Microvascular contractions were studied on a wire myograph. Cellular (ethidium: dihydroethidium) and mitochondrial (mitoSOX) ROS were measured by fluorescence microscopy. Mice with RRM had increased excretion of markers of oxidative stress, thromboxane, and microalbumin; increased plasma ET-1; and increased microvascular expression of p22(phox), cyclooxygenase-2, TP-Rs, preproendothelin and endothelin-A receptors, and increased arteriolar remodeling. They had increased contractions to U-46,619 (118 ± 3 versus 87 ± 6, P<0.05) and ET-1 (108 ± 5 versus 89 ± 4, P<0.05), which were dependent on cellular and mitochondrial ROS, cyclooxygenase-2, and TP-Rs. RRM doubled the ET-1-induced cellular and mitochondrial ROS generation (P<0.05). TP-R-/- mice with RRM lacked these abnormal structural and functional microvascular responses and lacked the increased systemic and the increased microvascular oxidative stress and circulating ET-1. In conclusion, RRM leads to microvascular remodeling and enhanced ET-1-induced cellular and mitochondrial ROS and contractions that are mediated by cyclooxygenase-2 products activating TP-Rs. Thus, TP-Rs can be upstream from enhanced ROS, ET-1, microvascular remodeling, and contractility and may thereby coordinate vascular dysfunction in chronic kidney disease.

  12. Targeted activation of endothelin-1 exacerbates hypoxia-induced pulmonary hypertension

    SciTech Connect

    Satwiko, Muhammad Gahan; Ikeda, Koji; Nakayama, Kazuhiko; Yagi, Keiko; Hocher, Berthold; Hirata, Ken-ichi; Emoto, Noriaki

    2015-09-25

    Pulmonary arterial hypertension (PAH) is a fatal disease that eventually results in right heart failure and death. Current pharmacologic therapies for PAH are limited, and there are no drugs that could completely cure PAH. Enhanced activity of endothelin system has been implicated in PAH severity and endothelin receptor antagonists have been used clinically to treat PAH. However, there is limited experimental evidence on the direct role of enhanced endothelin system activity in PAH. Here, we investigated the correlation between endothelin-1 (ET-1) and PAH using ET-1 transgenic (ETTG) mice. Exposure to chronic hypoxia increased right ventricular pressure and pulmonary arterial wall thickness in ETTG mice compared to those in wild type mice. Of note, ETTG mice exhibited modest but significant increase in right ventricular pressure and vessel wall thickness relative to wild type mice even under normoxic conditions. To induce severe PAH, we administered SU5416, a vascular endothelial growth factor receptor inhibitor, combined with exposure to chronic hypoxia. Treatment with SU5416 modestly aggravated hypoxia-induced pulmonary hypertension, right ventricular hypertrophy, and pulmonary arterial vessel wall thickening in ETTG mice in association with increased interleukin-6 expression in blood vessels. However, there was no sign of obliterative endothelial cell proliferation and plexiform lesion formation in the lungs. These results demonstrated that enhanced endothelin system activity could be a causative factor in the development of PAH and provided rationale for the inhibition of endothelin system to treat PAH. - Highlights: • Role of endothelin-1 in pulmonary arterial hypertension (PAH) was investigated. • The endothelin-1 transgenic (ETTG) and wild type (WT) mice were analyzed. • ETTG mice spontaneously developed PAH under normoxia conditions. • SU5416 further aggravated PAH in ETTG mice. • Enhanced endothelin system activity could be a causative factor in

  13. Endothelin receptors mediating functional responses in human small arteries and veins.

    PubMed Central

    Riezebos, J.; Watts, I. S.; Vallance, P. J.

    1994-01-01

    1. In the present study, responses of human omental small arteries and veins to endothelin-1 and endothelin-3 were characterized by use of the ETB receptor selective agonist, sarafotoxin S6c, the ETA receptor antagonist, BQ123, the ETB receptor antagonist, IRL1038, the NO-synthase inhibitor NG-monomethyl-L-arginine (L-NMMA, 300 microM) and indomethacin (10 microM). 2. Small arteries (internal diameter 413 +/- 22 microns) and parallel running veins (646 +/- 35 microns) were mounted in a myograph under a normalized tension equivalent to 90% of a transmural pressure of 100 mmHg and 19 mmHg in vivo, respectively. 3. In small arteries and veins, endothelin-1 caused a concentration-dependent increase in wall tension (Emax = 3.90 +/- 0.56 mN mm-1 and 1.90 m +/- 0.32 mN mm-1 respectively, P < 0.05) and was equipotent (arteries: pD2 = 8.91 +/- 0.11; veins: pD2 = 8.63 +/- 0.08, NS). In endothelium intact arteries, L-NMMA significantly enhanced the sensitivity to endothelin-1 (pD2 control: 8.92 +/- 0.16; pD2 L-NMMA: 9.37 +/- 0.11; P < 0.05). L-NMMA did not affect the sensitivity of veins to endothelin-1. Indomethacin was without effect in arteries and veins. In veins, endothelin-3 was about a hundred times less potent than endothelin-1 and showed a biphasic response curve. Small arteries did not contract to endothelin-3. Neither small arteries nor veins contracted to sarafotoxin S6c. Furthermore, no relaxation to endothelin-1 or sarafotoxin S6c was seen in any precontracted vessels.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8004404

  14. Association between endothelin receptor B nonsynonymous variants and melanoma risk.

    PubMed

    Soufir, Nadem; Meziani, Roubila; Lacapère, Jean-Jacques; Bertrand, Guylene; Fumeron, Frederic; Bourillon, Agnes; Gérard, Bénédicte; Descamps, Vincent; Crickx, Béatrice; Ollivaud, Laurence; Archimbaud, Alain; Lebbe, Céleste; Basset-Seguin, Nicole; Saiag, Philippe; Grandchamp, Bernard

    2005-09-07

    The endothelin signaling pathway plays a crucial role in melanocyte differentiation and migration. In this study, we investigated whether germline mutations of endothelin receptor B (EDNRB), a gene involved in Hirschsprung disease (HSCR), could also predispose for malignant melanoma (MM). The coding region of EDNRB was sequenced in 137 MM patients and in 130 ethnically matched Caucasian control subjects. Six nonsynonymous EDNRB variants were found in 15 patients (11%), but only two were found in four control subjects (3%, odds ratio [OR] = 3.87, 95% confidence interval [CI] = 1.25 to 12; P = .012). Overall, 14 out of 15 MM patients carried EDNRB mutations reported in HSCR, some of which had previously been shown to lead to loss of function. In multivariable logistic regression analysis including skin type, eye and hair color, number of nevi, and dorsal lentigines (freckles), the association between EDNRB mutations and MM risk remained statistically significant (OR = 19.9, 95% CI = 1.34 to 296.2; P = .03). Our data strongly suggest that EDNRB is involved in predisposition for two different multigenic disorders, HSCR and melanoma.

  15. Observation of ionic Coulomb blockade in nanopores

    NASA Astrophysics Data System (ADS)

    Feng, Jiandong; Liu, Ke; Graf, Michael; Dumcenco, Dumitru; Kis, Andras; di Ventra, Massimiliano; Radenovic, Aleksandra

    2016-08-01

    Emergent behaviour from electron-transport properties is routinely observed in systems with dimensions approaching the nanoscale. However, analogous mesoscopic behaviour resulting from ionic transport has so far not been observed, most probably because of bottlenecks in the controlled fabrication of subnanometre nanopores for use in nanofluidics. Here, we report measurements of ionic transport through a single subnanometre pore junction, and the observation of ionic Coulomb blockade: the ionic counterpart of the electronic Coulomb blockade observed for quantum dots. Our findings demonstrate that nanoscopic, atomically thin pores allow for the exploration of phenomena in ionic transport, and suggest that nanopores may also further our understanding of transport through biological ion channels.

  16. Endothelin system in intestinal villi: A possible role of endothelin-2/vasoactive intestinal contractor in the maintenance of intestinal architecture.

    PubMed

    Bianchi, Mariana; Adur, Javier; Takizawa, Satoshi; Saida, Kaname; Casco, Víctor H

    2012-01-27

    The endothelin system consists of three ligands (ET-1, ET-2 and ET-3) and at least two receptors (ETA and ETB). In mice ET-2 counterpart is a peptide originally called "vasoactive intestinal contractor" (VIC) for this reason, this peptide is frequently named ET-2/VIC. In intestinal villi, fibroblasts-like cells express endothelin's receptors and response to ET-1 and ET-3 peptides, changing their cellular shape. Several functions have been attributed to these peptides in the "architecture" maintenance of intestinal villi acting over sub-epithelial fibroblasts. Despite this, ET-2/VIC has not been analyzed in depth. In this work we show the intestine gene expression and immunolocalization of ET-1, ET-2 and the ETA and ETB receptors from duodenum to rectus and in the villus-crypt axis in mice, allowing a complete analysis of their functions. While ET-1 is expressed uniformly, ET-2 had a particular distribution, being higher at the bottom of the villi of duodenum, ileum and jejunum and reverting this pattern in the crypts of colon and rectus, where the higher expression was at the top. We postulated that ET-2 would act in a cooperative manner with ET-1, giving to the villus the straight enough to withstand mechanical stress.

  17. Endothelin-1 protects human melanocytes from UV-induced DNA damage by activating JNK and p38 signalling pathways.

    PubMed

    von Koschembahr, Anne M; Swope, Viki B; Starner, Renny J; Abdel-Malek, Zalfa A

    2015-04-01

    Endothelin-1 is a paracrine factor with mitogenic, melanogenic and survival effects on cultured human melanocytes. We report that endothelin-1 signalling reduced the generation and enhanced the repair of ultraviolet radiation (UV)-induced DNA photoproducts, and inhibited apoptosis of human melanocytes, without increasing cAMP levels, melanin content or proliferation. Treatment with endothelin-1 activated the MAP kinases JNK and p38, as evidenced by phosphorylation of their target, activating transcription factor-2 (ATF-2). Endothelin-1 also enhanced the phosphorylation of JNK, p38 and ATF-2 by UV. The effects of endothelin-1 were dependent on increasing intracellular calcium mobilization by endothelin B receptor signalling. Activation of both JNK and p38 was required for reducing DNA photoproducts, but only JNK partially contributed to the survival effect of endothelin-1. ATF-2 activation depended mainly on JNK, yet was not sufficient for the effect of endothelin-1 on UV-induced DNA damage, suggesting the requirement for other JNK and p38 targets for this effect. Our results underscore the significance of endothelin-1 and endothelin B receptor signalling in reducing the genotoxic effects of UV via activating JNK and p38, hence restoring genomic stability of melanocytes.

  18. Adenosine A2A receptor antagonism and neuroprotection: mechanisms, lights, and shadows.

    PubMed

    Popoli, Patrizia; Minghetti, Luisa; Tebano, Maria Teresa; Pintor, Annita; Domenici, Maria Rosaria; Massotti, Marino

    2004-01-01

    Adenosine A2A receptor antagonists are regarded as potential neuroprotective drugs, although the mechanisms underlying their effects remain to be elucidated. In this review, quinolinic acid (QA)-induced striatal toxicity was used as a tool to investigate the mechanisms of the neuroprotective effects of A2A receptor antagonists. After having examined the effects of selective A2A receptor antagonists toward different mechanisms of QA toxicity, we conclude that (1) the effect elicited by A2A receptor blockade on QA-induced glutamate outflow may be one of the mechanisms of the neuroprotective activity of A2A receptor antagonists; (2) A2A receptor antagonists have a potentially worsening influence on QA-dependent NMDA receptor activation; and (3) the ability of A2A receptor antagonists to prevent QA-induced lipid peroxidation does not correlate with the neuroprotective effects. These results suggest that A2A receptor antagonists may have either potentially beneficial or detrimental influence in models of neurodegeneration that are mainly due to increased glutamate levels or enhanced sensitivity of NMDA receptors, respectively.

  19. Polymorphisms in Endothelin System Genes, Arsenic Levels and Obesity Risk

    PubMed Central

    Martínez-Barquero, Vanesa; de Marco, Griselda; Martínez-Hervas, Sergio; Rentero, Pilar; Galan-Chilet, Inmaculada; Blesa, Sebastian; Morchon, David; Morcillo, Sonsoles; Rojo, Gemma; Ascaso, Juan Francisco; Real, José Tomás; Martín-Escudero, Juan Carlos; Chaves, Felipe Javier

    2015-01-01

    Background/Objectives Obesity has been linked to morbidity and mortality through increased risk for many chronic diseases. Endothelin (EDN) system has been related to endothelial function but it can be involved in lipid metabolism regulation: Receptor type A (EDNRA) activates lipolysis in adipocytes, the two endothelin receptors mediate arsenic-stimulated adipocyte dysfunction, and endothelin system can regulate adiposity by modulating adiponectin activity in different situations and, therefore, influence obesity development. The aim of the present study was to analyze if single nucleotide polymorphisms (SNPs) in the EDN system could be associated with human obesity. Subjects/Methods We analyzed two samples of general-population-based studies from two different regions of Spain: the VALCAR Study, 468 subjects from the area of Valencia, and the Hortega Study, 1502 subjects from the area of Valladolid. Eighteen SNPs throughout five genes were analyzed using SNPlex. Results We found associations for two polymorphisms of the EDNRB gene which codifies for EDN receptor type B. Genotypes AG and AA of the rs5351 were associated with a lower risk for obesity in the VALCAR sample (p=0.048, OR=0.63) and in the Hortega sample (p=0.001, OR=0.62). Moreover, in the rs3759475 polymorphism, genotypes CT and TT were also associated with lower risk for obesity in the Hortega sample (p=0.0037, OR=0.66) and in the VALCAR sample we found the same tendency (p=0.12, OR=0.70). Furthermore, upon studying the pooled population, we found a stronger association with obesity (p=0.0001, OR=0.61 and p=0.0008, OR=0.66 for rs5351 and rs3759475, respectively). Regarding plasma arsenic levels, we have found a positive association for the two SNPs studied with obesity risk in individuals with higher arsenic levels in plasma: rs5351 (p=0.0054, OR=0.51) and rs3759475 (p=0.009, OR=0.53) Conclusions Our results support the hypothesis that polymorphisms of the EDNRB gene may influence the susceptibility to

  20. ETA receptor blockade with atrasentan prevents hypertension with the multitargeted tyrosine kinase inhibitor ABT-869 in telemetry-instrumented rats.

    PubMed

    Banfor, Patricia N; Franklin, Pamela A; Segreti, Jason A; Widomski, Deborah L; Davidsen, Steven K; Albert, Daniel H; Cox, Bryan F; Fryer, Ryan M; Gintant, Gary A

    2009-02-01

    ABT-869 is a novel multitargeted inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptor tyrosine kinases (RTKs) with potent antiangiogenic properties that slow tumor progression. Vascular endothelial growth factor receptor blockade has been shown to produce hypertension. Atrasentan is a potent and selective endothelin (ETA) receptor antagonist that lowers blood pressure and affects tumor growth. To assess the utility of ETA receptor blockade in controlling hypertension with RTK inhibition, we evaluated the ability of atrasentan to block hypertension with ABT-869 in conscious, telemetry-instrumented rats. Changes in mean arterial pressure (MAP) and heart rate (HR) were evaluated using mean values and the area under the curve (AUC). Atrasentan (0.5, 1.5, and 5.0 mg kg(-1) d(-1) for 5 days) elicited dose-dependent decreases in MAP-AUC (-16.7 +/- 1.3, -20.94 +/- 3.68, and -30.12 +/- 3.57 mm Hg x day, respectively) compared with vehicle. ABT-869 (1, 3, 10, 30 mg kg(-1) d(-1) for 5 days) increased MAP compared with vehicle (MAP-AUC values of -5.52 +/- 3.75, 12.7 +/- 8.4, 37.5 +/- 4.4, and 63.8 +/- 3.3 mm Hg x day, respectively). Pretreatment with atrasentan (5 mg/kg for 5 days) prevented and abolished the hypertensive effects of ABT-869. Thus, ETA receptor blockade effectively alleviated hypertension with RTK inhibition and may serve a dual therapeutic role by preventing hypertension and slowing tumor progression.

  1. Correlation between Saliva and Plasma Levels of Endothelin Isoforms ET-1, ET-2, and ET-3.

    PubMed

    Gurusankar, Roma; Kumarathasan, Prem; Saravanamuthu, Anusha; Thomson, Errol M; Vincent, Renaud

    2015-01-01

    Although saliva endothelins are emerging as valuable noninvasive cardiovascular biomarkers, reports on the relationship between isoforms in saliva and plasma remain scarce. We measured endothelins in concurrent saliva and plasma samples (n = 30 males; age 18-63) by HPLC-fluorescence. Results revealed statistically significant positive correlations among all isoforms between saliva and plasma: big endothelin-1 (BET-1, 0.55 ± 0.27 versus 3.35 ± 1.28 pmol/mL; r = 0.38, p = 0.041), endothelin-1 (ET-1, 0.52 ± 0.21 versus 3.45 ± 1.28 pmol/mL; r = 0.53, p = 0.003), endothelin-2 (ET-2, 0.21 ± 0.07 versus 1.63 ± 0.66 pmol/mL; r = 0.51, p = 0.004), and endothelin-3 (ET-3, 0.39 ± 0.19 versus 2.32 ± 1.44 pmol/mL; r = 0.75, p < 0.001). Correlations of BET-1, ET-1, and ET-3 within each compartment were positive in both plasma (p < 0.05) and saliva (p ≤ 0.1), whereas ET-2 was not significantly correlated with other isoforms in either plasma or saliva. For all isoforms, concentrations varied on average fivefold between individuals (90th/10th percentiles); individuals with high plasma endothelin levels generally had high saliva endothelin levels. Our results reveal that salivary ET isoform profiles portray the plasmatic profiles and support the view of coordinated regulation of ET-1 and ET-3, but distinct regulatory pathways for ET-2.

  2. TIMAP-protein phosphatase 1-complex controls endothelin-1 production via ECE-1 dephosphorylation.

    PubMed

    Boratkó, Anita; Veréb, Zoltán; Petrovski, Goran; Csortos, Csilla

    2016-04-01

    Endothelin induced signaling pathways can affect blood pressure and vascular tone, but the influence of endothelins on tumor cells is also significant. We have detected elevated endothelin-1 secretion from TIMAP (TGF-β inhibited membrane associated protein) depleted vascular endothelial cells. The autocrine signaling activated by the elevated endothelin-1 level through the ETB receptors evoked an angiogenic-like phenotype, the cells assumed an elongated morphology, and enhanced tube formation and wound healing abilities. The depleted protein, TIMAP, is a highly specific and abundant protein in the endothelial cells, and it is a regulatory/targeting subunit for the catalytic subunit of protein phosphatase 1 (PP1c). Protein-protein interaction between the TIMAP-PP1c complex and the endothelin converting enzyme-1 (ECE-1) was detected, the latter of which is a transmembrane protein that produces the biologically active 21-amino acid form of endothelin-1 from proendothelin. The results indicate that silencing of TIMAP induces a reduction in TIMAP-PP1c activity connected to ECE-1. This leads to an increase in the amount of ECE-1 protein in the plasma membrane and a consequent increase in endothelin-1 secretion. Similarly, activation of PKC, the kinase responsible for ECE-1 phosphorylation increased ECE-1 protein level in the membrane fraction of the endothelial cells. The elevated ECE-1 level was mitigated in time in normal cells, but was clearly preserved in TIMAP-depleted cells. Overall, our results indicate that PKC-phosphorylated ECE-1 is a TIMAP-PP1c substrate and this phosphatase complex has an important role in endothelin-1 production of EC through the regulation of ECE-1 activity.

  3. Therapeutic potential of endothelin receptor antagonism in kidney disease.

    PubMed

    Czopek, Alicja; Moorhouse, Rebecca; Webb, David J; Dhaun, Neeraj

    2016-03-01

    Our growing understanding of the role of the endothelin (ET) system in renal physiology and pathophysiology is from emerging studies of renal disease in animal models and humans. ET receptor antagonists reduce blood pressure and proteinuria in chronic kidney disease and cause regression of renal injury in animals. However, the therapeutic potential of ET receptor antagonism has not been fully explored and clinical studies have been largely limited to patients with diabetic nephropathy. There remains a need for more work in nondiabetic chronic kidney disease, end-stage renal disease (patients requiring maintenance dialysis and those with a functioning kidney transplant), ischemia reperfusion injury, and sickle cell disease. The current review summarizes the most recent advances in both preclinical and clinical studies of ET receptor antagonists in the field of kidney disease.

  4. Endothelin produces systemic vasodilation independent of the state of consciousness.

    PubMed

    Lippton, H L; Pellett, A; Cairo, J; Summer, W R; Lowe, R F; Sander, G E; Giles, T D; Cohen, G; Levitzky, M G

    1989-01-01

    The effects of endothelin, ET-1, on pulmonary and systemic hemodynamics were studied in the open chest dog and changes in systemic arterial pressure in dogs under conscious and anesthetized states were compared. Rapid intravenous (IV) bolus injections of ET-1, 100-1,000 nanograms/kg, significantly decreased systemic arterial pressure, and significantly decreased systemic vascular resistance whereas left atrial pressure and pulmonary vascular resistance were not altered. Reductions in systemic arterial pressure in response to bolus injection of ET-1, 100 and 300 nanograms/kg IV, during conscious state and during anesthesia were similar, respectively. The present data suggest that ET-1 dilates the systemic vascular bed independent of the animal's state of consciousness. The present data also suggest that when compared to the systemic vascular bed, the pulmonary vascular bed is less responsive to bolus administration of ET-1.

  5. The role of endothelin-1 in pulmonary arterial hypertension

    PubMed Central

    Chester, Adrian H.; Yacoub, Magdi H.

    2014-01-01

    Pulmonary arterial hypertension (PAH) is a rare but debilitating disease, which if left untreated rapidly progresses to right ventricular failure and eventually death. In the quest to understand the pathogenesis of this disease differences in the profile, expression and action of vasoactive substances released by the endothelium have been identified in patients with PAH. Of these, endothelin-1 (ET-1) is of particular interest since it is known to be an extremely powerful vasoconstrictor and also involved in vascular remodelling. Identification of ET-1 as a target for pharmacological intervention has lead to the discovery of a number of compounds that can block the receptors via which ET-1 mediates its effects. This review sets out the evidence in support of a role for ET-1 in the onset and progression of the disease and reviews the data from the various clinical trials of ET-1 receptor antagonists for the treatment of PAH. PMID:25405182

  6. Early intervention with a potent endothelin-A/endothelin-B receptor antagonist aggravates left ventricular remodeling after myocardial infarction in rats.

    PubMed

    Oie, Erik; Yndestad, Arne; Robins, Simon P; Børnerheim, Reidar; Asberg, Anders; Attramadal, Håvard

    2002-05-01

    Intervention with selective endothelin (ET)A receptor antagonists within 24h after myocardial infarction (MI) in rats has been reported to aggravate left ventricular (LV) remodeling. In contrast, beneficial effects are reported when initiation of treatment is delayed 7 days or more after MI. However, bosentan, a mixed ET(A)/ET(B) receptor antagonist with low affinity for the ET receptors, has been shown to exert beneficial effects independent of the time point of initiation of treatment after MI. The aim of the present study was to investigate to what extent early intervention with a mixed ET(A)/ET(B) receptor antagonist with higher affinity at the ET receptors (SB 209670) would also exert beneficial effects on postinfarction LV remodeling. After ligation of the left coronary artery, rats were randomized to treatment with SB 209670 (6.25 mg x kg(-1) SC b.i.d., n = 10) or vehicle (n = 12) for 26 days, starting 48h after MI. Treatment with SB 209670 adversely affected the postinfarction remodeling process causing further dilatation of the LV (LV end-diastolic diameter: 10.4+/-0.5 vs 9.1+/-0.2 mm; LV end-systolic diameter: 8.5+/-0.4 vs 7.2+/-0.2 mm, P < 0.05). However, SB 209670 did not significantly affect infarct size, compensatory cardiac hypertrophy, nor the myocardial mRNA levels of procollagen type I and III, and prolyl 4-hydroxylase and lysyl oxidase, 2 important enzymes affecting collagen secretion, stability and functionality. In addition, SB 209670 had no significant effects on LV collagen cross-linking or extent of fibrosis. Thus, our data demonstrate that early intervention with a potent, mixed ET(A)/ET(B) receptor antagonist after MI may promote dilatation of the LV without significant alterations of infarct size and extracellular matrix composition. Our data support the notion that the timing of initiation of ET receptor antagonism after MI is critical and that potent ET receptor antagonists may be harmful during the first few days after MI.

  7. Histamine H1 and endothelin ETB receptors mediate phospholipase D stimulation in rat brain hippocampal slices.

    PubMed

    Sarri, E; Picatoste, F; Claro, E

    1995-08-01

    Different neurotransmitter receptor agonists [carbachol, serotonin, noradrenaline, histamine, endothelin-1, and trans-(1S,3R)-aminocyclopentyl-1,3-dicarboxylic acid (trans-ACPD)], known as stimuli of phospholipase C in brain tissue, were tested for phospholipase D stimulation in [32P]Pi-prelabeled rat brain cortical and hippocampal slices. The accumulation of [32P]phosphatidylethanol was measured as an index of phospholipase D-catalyzed transphosphatidylation in the presence of ethanol. Among the six neurotransmitter receptor agonists tested, only noradrenaline, histamine, endothelin-1, and trans-ACPD stimulated phospholipase D in hippocampus and cortex, an effect that was strictly dependent of the presence of millimolar extracellular calcium concentrations. The effect of histamine (EC50 18 microM) was inhibited by the H1 receptor antagonist mepyramine with a Ki constant of 0.7 nM and was resistant to H2 and H3 receptor antagonists (ranitidine and tioperamide, respectively). Endothelin-1-stimulated phospholipase D (EC50 44 nM) was not blocked by BQ-123, a specific antagonist of the ETA receptor. Endothelin-3 and the specific ETB receptor agonist safarotoxin 6c were also able to stimulate phospholipase D with efficacies similar to that of endothelin-1, and EC50 values of 16 and 3 nM, respectively. These results show that histamine and endothelin-1 stimulate phospholipase D in rat brain through H1 and ETB receptors, respectively.

  8. Endothelin-1 Pathway Polymorphisms and Outcomes in Pulmonary Arterial Hypertension

    PubMed Central

    Gomberg-Maitland, Mardi; Demarco, Teresa; Frost, Adaani E.; Torbicki, Adam; Langleben, David; Pulido, Tomas; Correa-Jaque, Priscilla; Passineau, Michael J.; Wiener, Howard W.; Tamari, Mayumi; Hirota, Tomomitsu; Kubo, Michiaki; Tiwari, Hemant K.

    2015-01-01

    Rationale: Pulmonary arterial hypertension (PAH) is a progressive fatal disease. Variable response and tolerability to PAH therapeutics suggests that genetic differences may influence outcomes. The endothelin pathway is central to pulmonary vascular function, and several polymorphisms and/or mutations in the genes coding for endothelin (ET)-1 and its receptors correlate with the clinical manifestations of other diseases. Objectives: To examine the interaction of ET-1 pathway polymorphisms and treatment responses of patients with PAH treated with ET receptor antagonists (ERAs). Methods: A total of 1,198 patients with PAH were prospectively enrolled from 45 U.S. and Canadian pulmonary hypertension centers or retrospectively from global sites participating in the STRIDE (Sitaxsentan To Relieve Impaired Exercise) trials. Comprehensive objective measures including a 6-minute-walk test, Borg dyspnea score, functional class, and laboratory studies were completed at baseline, before the initiation of ERAs, and repeated serially. Single-nucleotide polymorphisms from ET-1 pathway candidate genes were selected from a completed genome-wide association study performed on the study cohort. Measurements and Main Results: Patient efficacy outcomes were analyzed for a relationship between ET-1 pathway polymorphisms and clinical efficacy using predefined, composite positive and negative outcome measures in 715 European descent samples. A single-nucleotide polymorphism (rs11157866) in the G-protein alpha and gamma subunits gene was significantly associated, accounting for multiple testing, with a combined improvement in functional class and 6-minute-walk distance at 12 and 18 months and marginally significant at 24 months. Conclusions: ET-1 pathway associated polymorphisms may influence the clinical efficacy of ERA therapy for PAH. Further prospective studies are needed. PMID:26252367

  9. Endothelin stimulates chloride secretion across canine tracheal epithelium.

    PubMed

    Plews, P I; Abdel-Malek, Z A; Doupnik, C A; Leikauf, G D

    1991-08-01

    The endothelins (ET) are a group of isopeptides produced by a number of cells, including canine tracheal epithelial cells. Because these compounds are endogenous peptides that may activate eicosanoid metabolism, we investigated the effects of ET on Cl secretion in canine tracheal epithelium. Endothelin 1 (ET-1) was found to produce a dose-dependent change in short-circuit current (Isc) that increased slowly and reached a maximal value within 10-15 min. When isopeptides of ET were compared, 300 nM ET-1 and ET-2 produced comparable maximal increases in Isc, whereas ET-3 produced smaller changes in Isc (half-maximal concentrations of 2.2, 7.2, and 10.4 nM, respectively). Ionic substitution of Cl with nontransported anions, iodide and gluconate, reduced ET-1-induced changes in Isc. Furthermore, the response was inhibited by the NaCl cotransport inhibitor, furosemide. In paired tissues, ET-1 significantly increased mucosal net 36Cl flux without significant effect on 22Na flux. The increase in Isc induced by ET was diminished by pretreatment with indomethacin. The second messengers mediating the increase in Isc were investigated in cultured canine tracheal epithelial cells. ET-1 stimulated the release of [3H]arachidonate from membrane phospholipids, increased intracellular Ca2+ (occasionally producing oscillations), and increased adenosine 3',5'-cyclic monophosphate accumulation. The latter was diminished by indomethacin. Thus ET is a potent agonist of Cl secretion (with the isopeptides having the following potency: ET-1 greater than or equal to ET-2 greater than ET-3) and acts, in part, through a cyclooxygenase-dependent mechanism.

  10. Protection of malonate-induced GABA but not dopamine loss by GABA transporter blockade in rat striatum.

    PubMed

    Zeevalk, Gail D; Manzino, Lawrence; Sonsalla, Patricia K

    2002-07-01

    Previous work has shown that overstimulation of GABA(A) receptors can potentiate neuronal cell damage during excitotoxic or metabolic stress in vitro and that GABA(A) antagonists or GABA transport blockers are neuroprotective under these situations. Malonate, a reversible succinate dehydrogenase/mitochondrial complex II inhibitor, is frequently used in animals to model cell loss in neurodegenerative diseases such as Parkinson's and Huntington's diseases. To determine if GABA transporter blockade during mitochondrial impairment can protect neurons in vivo as compared with in vitro studies, rats received a stereotaxic infusion of malonate (2 micromol) into the left striatum to induce a metabolic stress. The nonsubstrate GABA transport blocker, NO711 (20 nmol) was infused in some rats 30 min before and 3 h following malonate infusion. After 1 week, dopamine and GABA levels in the striata were measured. Malonate caused a significant loss of striatal dopamine and GABA. Blockade of the GABA transporter significantly attenuated GABA, but not dopamine loss. In contrast with several in vitro reports, GABA(A) receptors were not a downstream mediator of protection by NO711. Intrastriatal infusion of malonate (2 micromol) plus or minus the GABA(A) receptor agonist muscimol (1 micromol), the GABA(A) Cl- binding site antagonist picrotoxin (50 nmol) or the GABA(B) receptor antagonist saclofen (33 nmol) did not modify loss of striatal dopamine or GABA when examined 1 week following infusion. These data show that GABA transporter blockade during mitochondrial impairment in the striatum provides protection to GABAergic neurons. GABA transporter blockade, which is currently a pharmacological strategy for the treatment of epilepsy, may thus also be beneficial in the treatment of acute and chronic conditions involving energy inhibition such as stroke/ischemia or Huntington's disease. These findings also point to fundamental differences between immature and adult neurons in the

  11. The pathophysiology of endothelin in complications after solid organ transplantation: a potential novel therapeutic role for endothelin receptor antagonists.

    PubMed

    Raina, Amresh; Horn, Edward T; Benza, Raymond L

    2012-11-15

    Although short-term allograft survival after solid organ transplantation has improved during the past two decades, improvement in long-term graft survival has been less pronounced. Common complications after transplantation include chronic allograft rejection, nephrotoxicity from calcineurin inhibitors (CNIs), and systemic hypertension, which all impact posttransplantation morbidity and mortality. Endothelin (ET)-1, a potent endogenous vasoconstrictor, inducer of fibrosis, and vascular smooth muscle cell proliferation, may play a key role in both the development of CNI-induced nephrotoxicity and endothelial vasculopathy in chronic allograft rejection. ET-1 levels increase after isograft implantation, and ET-1 plays a key role in CNI-induced renal vasoconstriction, sodium retention, and hypertension. Preclinical studies have demonstrated that endothelin receptor antagonists (ERAs) can reduce or prevent CNI-induced hypertension after renal transplantation. In addition, ERAs can ameliorate CNI-induced renal vasoconstriction and improve proteinuria and preserve renal function in animal models of renal transplantation. ET-1 may also play a significant role in cardiac allograft vasculopathy, and in animal models, ERAs improve pulmonary function and ischemic-reperfusion injury in lung transplantation and hepatic function and structure in liver transplantation. Emerging pharmacokinetic data suggest that the selective ERA ambrisentan may be used safely in conjunction with the most commonly used immunosuppressive agents tacrolimus and mycophenolate, albeit with appropriate dose adjustment. The weight of available evidence pointing toward a potential beneficial role of ERAs in ameliorating common complications after solid organ transplantation must be balanced with potential toxicities of ERAs but suggests that a randomized clinical trial of ERAs in transplant patients is warranted.

  12. Endothelin-converting enzyme-1 activity, endothelin-1 production, and free radical-dependent vasoconstriction in Alzheimer's disease.

    PubMed

    Palmer, Jennifer C; Tayler, Hannah M; Love, Seth

    2013-01-01

    Alzheimer's disease (AD) patients have reduced cerebral blood flow. This precedes dementia and may contribute to its progression. In mice that overexpress amyloid-β protein precursor, cerebral blood flow declines before the development of plaques or cognitive abnormalities. In the brain, endothelin-1 (ET-1) is a locally acting vasoconstrictor, produced in neurons by endothelin-converting enzyme (ECE)-2 and in endothelial cells by ECE-1. Both ECEs are also capable of cleaving amyloid-β (Aβ). We previously showed ECE-2 and ET-1 to be elevated in postmortem temporal cortex from AD patients, and ECE-2 expression and ET-1 release to be upregulated by Aβ42 in vitro. We have now studied isolated leptomeningeal blood vessels from postmortem brains and found that although ECE-1 level is reduced, ECE-1 activity and ET-1 level are significantly elevated in AD vessels. This is specific to AD as there is no specific change in vascular dementia vessels. In primary cultures of human brain endothelial cells, both Aβ40 and Aβ42 caused a significant increase in ET-1 release, the increase being particularly pronounced with Aβ40. In view of previous studies implicating free radicals in the endothelial dysfunction caused by Aβ40, we examined whether Aβ-mediated ET-1 release could be prevented by the antioxidant superoxide dismutase. Addition of superoxide dismutase to cells exposed to Aβ40 prevented the increase in the concentration of ET-1. Our findings indicate that cerebral vasoconstriction induced by Aβ results in part from a free radical-mediated increase in ECE-1 activity and ET-1 production.

  13. [Cancer immunotherapy by immuno-checkpoint blockade].

    PubMed

    Kawakami, Yutaka

    2015-10-01

    As cancer immunotherapies utilizing anti-tumor T-cell responses, immuno-checkpoint blockade and adoptive T-cell immunotherapy have recently achieved durable responses even in advanced cancer patients with metastases. Administration of antibodies on the T-cell surface, CTLA-4 and PD-1 (or PD-1 ligand PD-L1), resulted in tumor regression of not only melanoma and renal cell cancer which were known to be relatively sensitive to immunotherapy, but also various malignancies including lung, bladder, ovarian, gastric, and head and neck cancers, as well as hematological malignancies such as Hodgkin and B-cell malignant lymphomas. These findings have changed the status of immunotherapy in the development of cancer treatments. Currently, development of combinations employing cancer immunotherapy with immuno-checkpoint blockade, as well as personalized cancer immunotherapy based on the evaluation of pretreatment immune status, are in progress.

  14. Hippocampal 5-HT1A Receptor and Spatial Learning and Memory

    PubMed Central

    Glikmann-Johnston, Yifat; Saling, Michael M.; Reutens, David C.; Stout, Julie C.

    2015-01-01

    Spatial cognition is fundamental for survival in the topographically complex environments inhabited by humans and other animals. The hippocampus, which has a central role in spatial cognition, is characterized by high concentration of serotonin (5-hydroxytryptamine; 5-HT) receptor binding sites, particularly of the 1A receptor (5-HT1A) subtype. This review highlights converging evidence for the role of hippocampal 5-HT1A receptors in spatial learning and memory. We consider studies showing that activation or blockade of the 5-HT1A receptors using agonists or antagonists, respectively, lead to changes in spatial learning and memory. For example, pharmacological manipulation to induce 5-HT release, or to block 5-HT uptake, have indicated that increased extracellular 5-HT concentrations maintain or improve memory performance. In contrast, reduced levels of 5-HT have been shown to impair spatial memory. Furthermore, the lack of 5-HT1A receptor subtype in single gene knockout mice is specifically associated with spatial memory impairments. These findings, along with evidence from recent cognitive imaging studies using positron emission tomography (PET) with 5-HT1A receptor ligands, and studies of individual genetic variance in 5-HT1A receptor availability, strongly suggests that 5-HT, mediated by the 5-HT1A receptor subtype, plays a key role in spatial learning and memory. PMID:26696889

  15. Effect of beta blockade on singing performance.

    PubMed

    Gates, G A; Saegert, J; Wilson, N; Johnson, L; Shepherd, A; Hearne, E M

    1985-01-01

    The symptoms associated with performance anxiety, or the so-called stage fright syndrome, are similar to those of alpha and beta adrenergic stimulation. Suppression of symptoms and improvement in instrumentalist's performance after beta blockade suggest that this modality would be of benefit for singers as well. To evaluate the dose-effect relationship of beta blockade upon singing performance and the possible effect of these agents upon performance maturation, we studied 34 singing students during end of semester juries, using a double-blind crossover paradigm. Students performed once with either placebo, 20, 40, or 80 mg of nadolol, and again 48 hours later, with placebo. There was a significant dose-related, limiting effect upon intraperformance cardiac rate. A small, but statistically significant, dichotomous effect upon performance rating was noted: low-dose nadolol tended to enhance performance, whereas larger doses impaired performance. We conclude that the effects of low dose beta blockade upon singing are minimally helpful and high doses may detract from performance ability.

  16. Activation of purinergic receptors (P2) in the renal medulla promotes endothelin-dependent natriuresis in male rats.

    PubMed

    Gohar, Eman Y; Speed, Joshua S; Kasztan, Malgorzata; Jin, Chunhua; Pollock, David M

    2016-08-01

    Renal endothelin-1 (ET-1) and purinergic signaling systems regulate Na(+) reabsorption in the renal medulla. A link between the renal ET-1 and purinergic systems was demonstrated in vitro, however, the in vivo interaction between these systems has not been defined. To test whether renal medullary activation of purinergic (P2) receptors promotes ET-dependent natriuresis, we determined the effect of increased medullary NaCl loading on Na(+) excretion and inner medullary ET-1 mRNA expression in anesthetized adult male Sprague-Dawley rats in the presence and absence of purinergic receptor antagonism. Isosmotic saline (NaCl; 284 mosmol/kgH2O) was infused into the medullary interstitium (500 μl/h) during a 30-min baseline urine collection period, followed by isosmotic or hyperosmotic saline (1,800 mosmol/kgH2O) for two further 30-min urine collection periods. Na(+) excretion was significantly increased during intramedullary infusion of hyperosmotic saline. Compared with isosmotic saline, hyperosmotic saline infused into the renal medulla caused significant increases in inner medullary ET-1 mRNA expression. Renal intramedullary infusion of the P2 receptor antagonist suramin inhibited the increase in Na(+) excretion and inner medullary ET-1 mRNA expression induced by NaCl loading in the renal medulla. Activation of medullary P2Y2/4 receptors by infusion of UTP increased urinary Na(+) excretion. Combined ETA and ETB receptor blockade abolished the natriuretic response to intramedullary infusion of UTP. These data demonstrate that activation of medullary P2 receptors promotes ET-dependent natriuresis in male rats, suggesting that the renal ET-1 and purinergic signaling systems interact to efficiently facilitate excretion of a NaCl load.

  17. Gene silencing of endothelial von Willebrand Factor attenuates angiotensin II-induced endothelin-1 expression in porcine aortic endothelial cells

    PubMed Central

    Dushpanova, Anar; Agostini, Silvia; Ciofini, Enrica; Cabiati, Manuela; Casieri, Valentina; Matteucci, Marco; Del Ry, Silvia; Clerico, Aldo; Berti, Sergio; Lionetti, Vincenzo

    2016-01-01

    Expression of endothelin (ET)-1 is increased in endothelial cells exposed to angiotensin II (Ang II), leading to endothelial dysfunction and cardiovascular disorders. Since von Willebrand Factor (vWF) blockade improves endothelial function in coronary patients, we hypothesized that targeting endothelial vWF with short interference RNA (siRNA) prevents Ang II-induced ET-1 upregulation. Nearly 65 ± 2% silencing of vWF in porcine aortic endothelial cells (PAOECs) was achieved with vWF-specific siRNA without affecting cell viability and growth. While showing ET-1 similar to wild type cells at rest, vWF-silenced cells did not present ET-1 upregulation during exposure to Ang II (100 nM/24 h), preserving levels of endothelial nitric oxide synthase activity similar to wild type. vWF silencing prevented AngII-induced increase in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity and superoxide anion (O2−) levels, known triggers of ET-1 expression. Moreover, no increase in O2− or ET-1 levels was found in silenced cells treated with AngII or NOX-agonist phorbol ester (PMA 5 nM/48 h). Finally, vWF was required for overexpression of NOX4 and NOX2 in response to AngII and PMA. In conclusion, endothelial vWF knockdown prevented Ang II-induced ET-1 upregulation through attenuation of NOX-mediated O2− production. Our findings reveal a new role of vWF in preventing of Ang II-induced endothelial dysfunction. PMID:27443965

  18. Pulmonary vasoreactivity in spontaneously hypertensive rats - Effects of endothelin-1 and leptin

    PubMed Central

    2014-01-01

    Background Systemic hypertension may be associated with an increased pulmonary vascular resistance, which we hypothesized could be, at least in part, mediated by increased leptin. Methods Vascular reactivity to phenylephrine (1 μmol/L), endothelin-1 (10 nmol/L) and leptin (0.001–100 nmol/L) was evaluated in endothelium-intact and -denuded isolated thoracic aorta and pulmonary arteries from spontaneously hypertensive versus control Wistar rats. Arteries were sampled for pathobiological evaluation and lung tissue for morphometric evaluation. Results In control rats, endothelin-1 induced a higher level of contraction in the pulmonary artery than in the aorta. After phenylephrine or endothelin-1 precontraction, leptin relaxed intact pulmonary artery and aortic rings, while no response was observed in denuded arteries. Spontaneously hypertensive rats presented with increased reactivity to phenylephrine and endothelin-1 in endothelium-intact pulmonary arteries. After endothelin-1 precontraction, endothelium-dependent relaxation to leptin was impaired in pulmonary arteries from hypertensive rats. In both strains of rats, aortic segments were more responsive to leptin than pulmonary artery. In hypertensive rats, pulmonary arteries exhibited increased pulmonary artery medial thickness, associated with increased expressions of preproendothelin-1, endothelin-1 receptors type A and B, inducible nitric oxide synthase and decreased endothelial nitric oxide synthase, together with decreased leptin receptor and increased suppressor of cytokine signaling 3 expressions. Conclusions Altered pulmonary vascular reactivity in hypertension may be related to a loss of endothelial buffering of vasoconstriction and decreased leptin-induced vasodilation in conditions of increased endothelin-1. PMID:24499246

  19. Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution

    PubMed Central

    Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J.; Reed, William

    2007-01-01

    Background Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. Objectives The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. Methods We conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Results Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 μm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03). Conclusions Chronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure. PMID:17687455

  20. Acute increases of renal medullary osmolality stimulate endothelin release from the kidney.

    PubMed

    Boesen, Erika I; Pollock, David M

    2007-01-01

    Experiments conducted in vitro suggest that high osmolality stimulates endothelin production and release by renal tubular epithelial cells. Whether hyperosmotic solutions exert similar effects in vivo is unknown. Therefore, we tested the hypothesis that increasing renal medullary osmolality enhances urinary excretion of endothelin in anesthetized rats. Isosmotic NaCl (284 mosmol/kgH(2)O) was infused either intravenously (1.5 ml/h) or into the renal medullary interstitium (0.5 ml/h) during a 1-h equilibration period and 30-min baseline urine collection period, followed by either isosmotic or hyperosmotic NaCl (921 or 1,664 mosmol/kgH(2)O iv; 1,714 mosmol/kgH(2)O into renal medulla) for two further 30-min periods. Compared with isosmotic NaCl, infusion of hyperosmotic NaCl into the renal medulla significantly increased the endothelin excretion rate (P < 0.05; from 0.30 +/- 0.02 to 0.49 +/- 0.03 fmol/min). Intravenous infusion of hyperosmotic NaCl also significantly increased endothelin excretion rate in a concentration-dependent manner (from 0.79 +/- 0.07 to 1.77 +/- 0.16 fmol/min and 0.59 +/- 0.04 to 1.11 +/- 0.08 fmol/min for 1,664 and 921 mosmol/kgH(2)O, respectively). To differentiate between effects of osmolality and NaCl, similar experiments were performed using mannitol solutions. Compared with isosmotic mannitol, medullary interstitial infusion of hyperosmotic mannitol (1,820 mosmol/kgH(2)O) significantly increased endothelin excretion rate (P < 0.05; from 0.54 +/- 0.03 to 0.94 +/- 0.12 fmol/min). Thus exposing the renal medulla to hyperosmotic concentrations of either NaCl or mannitol stimulates endothelin release in vivo, consistent with medullary osmolality being an important regulator of renal endothelin synthesis.

  1. Coronary effects of endothelin-1 and vasopressin during acute hypotension in anesthetized goats.

    PubMed

    Fernández, Nuria; Martínez, Ma Angeles; García-Villalón, Angel Luis; Monge, Luis; Diéguez, Godofredo

    2005-06-10

    Coronary effects of endothelin-1 and vasopressin during acute hypotension, and the role of NO and prostanoids in these effects were examined in anesthetized goats. Left circumflex coronary artery flow was measured electromagnetically, and hypotension was induced by constriction of the caudal vena cava in animals non-treated (7 goats) or treated with the inhibitor of NO synthesis N(w)-nitro-L-arginine methyl esther (L-NAME, 5 goats), the cyclooxygenase inhibitor meclofenamate (5 goats) or both drugs (5 goats). Under normotension (22 goats), mean arterial pressure averaged 93 +/- 3 mm Hg and coronary vascular conductance (CVC) 0.37 +/- 0.025 ml/min/mm Hg. Endothelin-1 (0.01-0.3 nmol) and vasopressin (0.03-1 nmol), intracoronarily injected, dose-dependently decreased CVC by up to 56% for endothelin-1 and 40% for vasopressin. During hypotension in every condition tested, mean arterial pressure decreased to approximately 60 mm Hg, and CVC only decreased during hypotension pretreated with L-NAME (23%) or L-NAME + meclofenamate (34%). Under non-treated hypotension, the decreases in CVC by endothelin-1 were augmented approximately 1.5 fold, and those by vasopressin were not modified. This increase in CVR by endothelin-1 was not affected by L-NAME and was reversed by meclofenamate or L-NAME + meclofenamate. The coronary effects of vasopressin were not modified by any of these treatments. Therefore, acute hypotension increases the coronary vasoconstriction in response to endothelin-1 but not to vasopressin. This increased response to endothelin-1 may be related to both inhibition of NO release and release of vasoconstrictor prostanoids.

  2. Risk Factors in Normal-Tension Glaucoma and High-Tension Glaucoma in relation to Polymorphisms of Endothelin-1 Gene and Endothelin-1 Receptor Type A Gene

    PubMed Central

    Wróbel-Dudzińska, Dominika; Kosior-Jarecka, Ewa; Łukasik, Urszula; Kocki, Janusz; Witczak, Agnieszka; Mosiewicz, Jerzy; Żarnowski, Tomasz

    2015-01-01

    The aim of the research is to analyse the influence of polymorphisms of endothelin-1 gene and endothelin-1 receptor type A gene on the clinical condition of patients with primary open angle glaucoma. Methods. 285 Polish patients took part in the research (160 normal-tension glaucoma and 125 high-tension glaucoma). DNA was isolated by standard methods and genotype distributions of four polymorphisms in genes encoding endothelin-1 (K198N) and endothelin-1 receptor type A polymorphisms (C1222T, C70G, and G231A) were determined. Genotype distributions were compared between NTG and HTG groups. The clinical condition of participants was examined for association with polymorphisms. Results. A similar frequency of occurrence of the polymorphic varieties of the studied genes was observed in patients with NTG and HTG. There is no relation between NTG risk factors and examined polymorphisms. NTG patients with TT genotype of K198N polymorphism presented with the lowest intraocular pressure in comparison to GG + GT genotype (p = 0.03). In NTG patients with CC genotype of C1222T polymorphism (p = 0.028) and GG of C70G polymorphism (p = 0.03) the lowest values of mean blood pressure were observed. Conclusions. The studied polymorphic varieties (K198N, C1222T) do have an influence on intraocular pressure as well as arterial blood pressure in NTG patients. PMID:26697209

  3. The supramammillary nucleus mediates primary reinforcement via GABA(A) receptors.

    PubMed

    Ikemoto, Satoshi

    2005-06-01

    The supramammillary nucleus (SUM), a dorsal layer of the mammillary body, has recently been implicated in positive reinforcement. The present study examined whether GABA(A) receptors in the SUM or adjacent regions are involved in primary reinforcement using intracranial self-administration procedures. Rats learned quickly to lever-press for infusions of the GABA(A) antagonist picrotoxin into the SUM. Although picrotoxin was also self-administered into the posterior hypothalamic nuclei and anterior ventral tegmental area, these regions were less responsive to lower doses of picrotoxin than the SUM. The finding that rats learned to respond selectively on the lever triggering drug infusions is consistent with picrotoxin's reinforcing effect. Coadministration of the GABA(A) agonist muscimol disrupted picrotoxin self-administration, and another GABA(A) antagonist, bicuculline, was also self-administered into the SUM; thus, the reinforcing effect of picrotoxin is mediated by GABA(A) receptors. Since rats did not self-administer the GABA(B) antagonist 2-hydroxysaclofen into the SUM, the role of GABA(B) receptors may be distinct from that of GABA(A) receptors. Pretreatment with the dopamine receptor antagonist SCH 23390 (0.05 mg/kg, i.p.) extinguished picrotoxin self-administration into the SUM, suggesting that the reinforcing effects of GABA(A) receptor blockade depend on normal dopamine transmission. In conclusion, the blockade of GABA(A) receptors in the SUM is reinforcing, and the brain 'reward' circuitry appears to be tonically inhibited via supramammillary GABA(A) receptors and more extensive than the meso-limbic dopamine system.

  4. Design, synthesis and biological activity of novel non-peptidyl endothelin converting enzyme inhibitors, 1-phenyl-tetrazole-formazan analogues.

    PubMed

    Yamazaki, Kazuto; Hasegawa, Hirohiko; Umekawa, Kayo; Ueki, Yasuyuki; Ohashi, Naohito; Kanaoka, Masaharu

    2002-05-06

    A novel non-peptidyl endothelin converting enzyme inhibitor was obtained through a pharmacophore analysis of known inhibitors and three-dimensional structure database search. Analogues of the new inhibitor were designed using the structure-activity relationship of known inhibitors and synthesized. In anesthetized rats, intraperitoneal administration of the analogues suppressed the pressor responses induced by big endothelin-1.

  5. Endothelin-converting enzymes and related metalloproteases in Alzheimer's disease.

    PubMed

    Pacheco-Quinto, Javier; Herdt, Aimee; Eckman, Christopher B; Eckman, Elizabeth A

    2013-01-01

    The efficient clearance of amyloid-β (Aβ) is essential to modulate levels of the peptide in the brain and to prevent it from accumulating in senile plaques, a hallmark of Alzheimer's disease (AD) pathology.We and others have shown that failure in Aβ catabolism can produce elevations in Aβ concentration similar to those observed in familial forms of AD. Based on the available evidence, it remains plausible that in late-onset AD, disturbances in the activity of Aβ degrading enzymes could induce Aβ accumulation, and that this increase could result in AD pathology. The following review presents a historical perspective of the parallel discovery of three vasopeptidases (neprilysin and endothelin-converting enzymes-1 and -2) as important Aβ degrading enzymes. The recognition of the role of these vasopeptidases in Aβ degradation, beyond bringing to light a possible explanation of how cardiovascular risk factors may influence AD risk, highlights a possible risk of the use of inhibitors of these enzymes for other clinical indications such as hypertension. We will discuss in detail the experiments conducted to assess the impact of vasopeptidase deficiency (through pharmacological inhibition or genetic mutation) on Aβ accumulation, as well as the cooperative effect of multiple Aβ degrading enzymes to regulate the concentration of the peptide at multiple sites, both intracellular and extracellular, throughout the brain.

  6. Endothelin-1 enhances the melanogenesis via MITF-GPNMB pathway

    PubMed Central

    Zhang, Ping; Liu, Wei; Yuan, Xiaoying; Li, Dongguang; Gu, Weijie; Gao, Tianwen

    2013-01-01

    Endothelin-1 (ET-1) plays an indispensable role in epidermal pigmentation in hyperpigmentary disorders due to a central role in melanogenesis. Nevertheless, precise mechanism involved in ET-1-induced hyperpigmentation is still undefined. Glycoprotein (transmembrane) non-metastatic melanoma protein b (GPNMB) is a key element in melanosome formation. Therefore, we speculated that GPNMB was correlated with ET-1-induced pigmentation. After culturing with ET-1, melanin synthesis was significantly up-regulated, accompanying with increased expression of GPNMB and microphthalmia-associated transcription factor (MITF). Total number of melanosomes and melanin synthesis were sharply reduced via GPNMB-siRNA transfection, indicating ET-1-induced pigmentation by GPNMB-dependent manner. Furthermore, MITFsiRNA transfection strikingly inhibited GPNMB expression and the melanogenesis, and this suppression failed to be alleviated by ET-1 stimulation. All of these results demonstrated that ET-1 can trigger melanogenesis via the MITF-regulated GPNMB pathway. Taken together, these findings will provide a new explanation of how ET-1 induces hyperpigmentation, and possibly supply a new strategy for cosmetic studies. [BMB Reports 2013; 46(7): 364-369] PMID:23884103

  7. Effects of endothelin on the mechanical activity and cytosolic calcium level of various types of smooth muscle.

    PubMed Central

    Sakata, K.; Ozaki, H.; Kwon, S. C.; Karaki, H.

    1989-01-01

    1. Effects of porcine/human endothelin (endothelin-1), a novel vasoconstrictor peptide, on various smooth muscles were examined. 2. In rat aorta, endothelin (1 pM-30nM) induced contraction in a concentration-dependent manner. Removal of endothelium shifted the concentration-response curve to the left. When added during the sustained contraction induced by 0.1 microM noradrenaline, endothelin (1 nM) induced a relaxation that was inhibited by removing endothelium or by methylene blue. 3. In rat aorta without endothelium, endothelin (1-30 nM) increased cytosolic Ca2+ level [( Ca2+]cyt) followed by contraction. Endothelin induced less contraction than high K+ at a given [Ca2+] cyt when the concentration of endothelin was lower (1-3nm) and/or during the early phase of the contraction (less than 10 min). In contrast, endothelin induced a greater contraction than KCl after prolonged exposure to high concentrations (greater than 10 nM). 4. The increase in [Ca2+]cyt due to endothelin was strongly inhibited by 10 microM verapamil or 0.3 microM nicardipine although muscle contraction was only partially inhibited. 5.In Ca2+ -free solution, endothelin (30 nM) induced a transient increase in [Ca2+] cyt and a slow increase in muscle tension. After a prolonged incubation in Ca2+-free solution, endothelin (30 nM) still induced a slow increase in tension without changing [Ca2+]cyt. This contraction was inhibited by 1 microM sodium nitropusside or 10 microM forskolin. 6. In canine trachea and guinea-pig uterus, endothelin (30 nM) induced sustained contraction with an increase in [Ca2+]cyt. In the absence of external Ca2+, endothelin (30 nM) induced a sustained contraction in canine trachea without changing [Ca2+]cyt. In guinea-pig vas deferens, taenia caeci and ileal longitudinal muscle, endothelin induced small increases in [Ca2+]cyt and tension. 7. In permeabilized smooth muscles, endothelin (30 nM) did not change the muscle tone. 8. These results suggest that endothelin acts on

  8. Immunological and structural characterization of sarafotoxin/endothelin family of peptides.

    PubMed

    Fleminger, G; Bousso-Mittler, D; Bdolah, A; Kloog, Y; Sokolovsky, M

    1989-08-15

    A highly specific and sensitive radioimmunoassay (RIA) was developed for the potent vasoconstrictor peptides, sarafotoxin-b and human endothelin. The antigenic determinants of the antibodies employed in studies with these assays were found to be localized within the amino acid sequence at positions 4-7. This was confirmed by CNBr cleavage of the methionyl residue at position 6 in the sarafotoxin and at position 7 in the endothelin. The chemically characterized modified peptides showed very low cross reactivity in the RIAs. On the other hand, the binding properties as well as the ability to induce phosphoinositide hydrolysis were very similar in the modified and native peptides, indicating that despite cleavage of the peptide bond the biologically active conformation responsible for either binding or phosphoinositide hydrolysis is retained, probably because of the disulfide bonds. Thus, structural alteration might be a valuable means of curtailing some of the various activities induced by the sarafotoxin/endothelin family of peptides.

  9. Therapeutic Opportunities for Caffeine and A2A Receptor Antagonists in Retinal Diseases.

    PubMed

    Boia, Raquel; Ambrósio, António Francisco; Santiago, Ana Raquel

    2016-01-01

    Caffeine, the major component of coffee, is the most consumed psychostimulant in the world. Caffeine is an adenosine analog and acts as a nonselective adenosine receptor antagonist. The majority of the effects of caffeine are mainly mediated by the blockade of adenosine receptors, and the proved neuroprotective effects of caffeine in brain disorders have been mimicked by the blockade of adenosine A2A receptor (A2AR). A growing body of evidence demonstrates that microglia-mediated neuroinflammation plays a key role in the pathophysiology of brain and retinal diseases. Moreover, the control of microglia reactivity by blocking A2AR has been proposed to be the mechanism underlying the observed protective effects of caffeine. Hence, it is conceivable that caffeine and A2AR antagonists offer therapeutic value for the treatment of retinal diseases, mainly those involving microglia-mediated neuroinflammation.

  10. Increased cerebrovascular sensitivity to endothelin-1 in a rat model of obstructive sleep apnea: a role for endothelin receptor B

    PubMed Central

    Durgan, David J; Crossland, Randy F; Lloyd, Eric E; Phillips, Sharon C; Bryan, Robert M

    2015-01-01

    Obstructive sleep apnea (OSA) is associated with cerebrovascular diseases. However, little is known regarding the effects of OSA on the cerebrovascular wall. We tested the hypothesis that OSA augments endothelin-1 (ET-1) constrictions of cerebral arteries. Repeated apneas (30 or 60 per hour) were produced in rats during the sleep cycle (8 hours) by remotely inflating a balloon implanted in the trachea. Four weeks of apneas produced a 23-fold increase in ET-1 sensitivity in isolated and pressurized posterior cerebral arteries (PCAs) compared with PCAs from sham-operated rats (EC50=10−9.2 mol/L versus 10−10.6 mol/L; P<0.001). This increased sensitivity was abolished by the ET-B receptor antagonist, BQ-788. Constrictions to the ET-B receptor agonist, IRL-1620, were greater in PCAs from rats after 2 or 4 weeks of apneas compared with that from sham-operated rats (P=0.013). Increased IRL-1620 constrictions in PCAs from OSA rats were normalized with the transient receptor potential channel (TRPC) blocker, SKF96365, or the Rho kinase (ROCK) inhibitor, Y27632. These data show that OSA increases the sensitivity of PCAs to ET-1 through enhanced ET-B activity, and enhanced activity of TRPCs and ROCK. We conclude that enhanced ET-1 signaling is part of a pathologic mechanism associated with adverse cerebrovascular outcomes of OSA. PMID:25425077

  11. Assessment of the link between endothelin K198n Snp, endothelin concentration and acute myocardial infarction in Egyptians.

    PubMed

    Abdel Rahman, Mohamed F; Hashad, Ingy M; Abou-Aisha, Khaled; Abdel Maksoud, Sahar M; Gad, Mohamed Z

    2017-01-01

    The aim of the current study was to assess the link between EDN K198N SNP, ET-1 serum concentration and acute myocardial infarction (AMI) in Egyptians. The study cohort consisted of 84 patients at AMI onset and 84 age-matched healthy controls. Endothelin genotypes and concentrations were determined by sequencing and ELISA, respectively. Genotype distribution was not significantly different between AMI patients and controls (P=.8341). The mean serum ET-1 concentration of patients (13.83±0.7 pg/mL) was significantly higher than controls (7.26±0.2 pg/mL) (P<.0001). ET-1 serum concentrations did not vary significantly among various EDN genotypes in patients (P=.378) and controls (P=.6164). Hence, we conclude that EDN K198N genotypes were not related to either ET-1 concentration or incidence of early-onset AMI in Egyptians. But, AMI patients had higher ET-1 concentrations than controls.

  12. Endothelin-1 increases melanin synthesis in an established sheep skin melanocyte culture.

    PubMed

    Pang, Yamiao; Geng, Jianjun; Qin, Yilong; Wang, Haidong; Fan, Ruiwen; Zhang, Ying; Li, Hongquan; Jiang, Shan; Dong, Changsheng

    2016-08-01

    The aims of the study were to establish a culture system for sheep skin melanocytes and uncover the effects of endothelin-1 on melanin synthesis in cultured melanocytes in order to provide an optimal cell system and a theoretical basis for studying the regulatory mechanism of coat color in sheep. In this study, skin punch biopsies were harvested from the dorsal region of 1-3-yr-old sheep, and skin melanocytes were then obtained by the two-step digestion using dispase II and trypsin/ethylene diamine tetraacetic acid (EDTA). The primary cultures of the melanocytes were established and characterized by dopa-staining, immunocytochemical localization of melanocyte markers, and RT-polymerase chain reaction (PCR) analysis of coat color genes. To determine the effect of endothelin-1 on proliferation and melanin synthesis of melanocytes, the cultured cells were treated with different doses of endothelin-1 (10(-7), 10(-8), 10(-9), 10(-10), and 0 mol/L), and the growth rate of melanocytes, production of melanin, expression of related genes, and location of related protein in cultured cells were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), ultraviolet spectrophotometry, qRT-PCR, and immunocytochemical localization, respectively. The results showed that the established melanocyte culture functions properly. Endothelin-1 treatment increased markedly the number of melanocytes and melanin content. In responding to this treatment, expressions of microphthalmia-associated transcription factor (MITF), melanocortin 1 receptor (MC1R), tyrosinase (TYR), and endothelin receptor B (EDNRB) in the melanocytes were significantly up regulated (P < 0.05). Immunocytochemical localization revealed that TYR was mainly localized in the cytoplasm. Positive staining of TYR in the melanocytes was significant. The findings demonstrated that the culture system of sheep skin melanocytes was established successfully in vitro, and endothelin-1 promotes the

  13. Specification of the mouse cardiac conduction system in the absence of Endothelin signaling.

    PubMed

    Hua, Lisa L; Vedantham, Vasanth; Barnes, Ralston M; Hu, Jianxin; Robinson, Ashley S; Bressan, Michael; Srivastava, Deepak; Black, Brian L

    2014-09-15

    Coordinated contraction of the heart is essential for survival and is regulated by the cardiac conduction system. Contraction of ventricular myocytes is controlled by the terminal part of the conduction system known as the Purkinje fiber network. Lineage analyses in chickens and mice have established that the Purkinje fibers of the peripheral ventricular conduction system arise from working myocytes during cardiac development. It has been proposed, based primarily on gain-of-function studies, that Endothelin signaling is responsible for myocyte-to-Purkinje fiber transdifferentiation during avian heart development. However, the role of Endothelin signaling in mammalian conduction system development is less clear, and the development of the cardiac conduction system in mice lacking Endothelin signaling has not been previously addressed. Here, we assessed the specification of the cardiac conduction system in mouse embryos lacking all Endothelin signaling. We found that mouse embryos that were homozygous null for both ednra and ednrb, the genes encoding the two Endothelin receptors in mice, were born at predicted Mendelian frequency and had normal specification of the cardiac conduction system and apparently normal electrocardiograms with normal QRS intervals. In addition, we found that ednra expression within the heart was restricted to the myocardium while ednrb expression in the heart was restricted to the endocardium and coronary endothelium. By establishing that ednra and ednrb are expressed in distinct compartments within the developing mammalian heart and that Endothelin signaling is dispensable for specification and function of the cardiac conduction system, this work has important implications for our understanding of mammalian cardiac development.

  14. Impact of Superoxide Dismutase Mimetic AEOL 10150 on the Endothelin System of Fischer 344 Rats

    PubMed Central

    Ganesh, Devi; Kumarathasan, Prem; Thomson, Errol M.; St-Germain, Carly; Blais, Erica; Crapo, James; Vincent, Renaud

    2016-01-01

    Endothelin-1 is a potent vasoconstrictor and mitogenic peptide involved in the regulation of vasomotor tone and maintenance of blood pressure. Oxidative stress activates the endothelin system, and is implicated in pulmonary and cardiovascular diseases including hypertension, congestive heart failure, and atherosclerosis. Superoxide dismutase mimetics designed with the aim of treating diseases that involve reactive oxygen species in their pathophysiology may exert a hypotensive effect, but effects on the endothelin system are unknown. Our objective was to determine the effect of the superoxide dismutase mimetic AEOL 10150 on the basal endothelin system in vivo. Male Fischer-344 rats were injected subcutaneously with 0, 2 or 5 mg/kg body weight of AEOL 10150 in saline. Plasma oxidative stress markers and endothelins (bigET-1, ET-1, ET-2, ET-3) as well as lung and heart endothelin/nitric oxide system gene expressions were measured using HPLC-Coularray, HPLC-Fluorescence and RT-PCR respectively. AEOL 10150 reduced (p<0.05) the circulating levels of isoprostane (-25%) and 3-nitrotyrosine (-50%) measured in plasma 2h and 24h after treatment, confirming delivery of a physiologically-relevant dose and the potent antioxidant activity of the drug. The reduction in markers of oxidative stress coincided with sustained 24h decrease (p<0.05) of plasma levels of ET-1 (-50%) and ET-3 (-10%). Expression of preproET-1 and endothelin converting enzyme-1 mRNA were not altered significantly in the lungs. However preproET-1 (not significant) and ECE-1 mRNA (p<0.05) were increased (10–25%) in the heart. Changes in the lungs included decrease (p<0.05) of mRNA for the ET-1 clearance receptor ETB and the vasoconstriction-signaling ETA receptor (-30%), and an early surge of inducible nitric oxide synthase expression followed by sustained decrease (-40% after 24 hours). The results indicate that interception of the endogenous physiological flux of reactive nitrogen species and reactive

  15. Nitrogen Oxide, Endothelin-1, and Serotonin in the Blood of Immature Spontaneously Hypertensive Rats.

    PubMed

    Chibireva, M D; Aflyatumova, G N; Matveeva, V L; Bilalova, D F; Kuz'mina, O I; Sadykova, D I; Nigmatullina, R R

    2017-01-01

    Endothelial function is an early and sensitive marker of subclinical increase of BP in children and adolescents. It is associated with an imbalance of the key vasoactive factors (NO, endothelin-1, and serotonin). Immature spontaneously hypertensive rats (SHR line) are characterized by increased plasma concentrations of NO and endothelin-1 (by 14.7% and 2.9 times, respectively) and increased serotonin content in the plasma and platelets (by 2.7 and 2.3 times, respectively) in comparison with Wistar-Kyoto rats. Platelet count in the blood of SHR rats is by 50% higher than in Wistar-Kyoto rats.

  16. Endothelin Receptors, Mitochondria and Neurogenesis in Cerebral Ischemia

    PubMed Central

    Gulati, Anil

    2016-01-01

    Background: Neurogenesis is most active during pre-natal development, however, it persists throughout the human lifespan. The putative role of mitochondria in neurogenesis and angiogenesis is gaining importance. Since, ETB receptor mediated neurogenesis and angiogenesis has been identified, the role of these receptors with relevance to mitochondrial functions is of interest. Methods: In addition to work from our laboratory, we undertook an extensive search of bibliographic databases for peer-reviewed research literature. Specific technical terms such as endothelin, mitochondria and neurogenesis were used to seek out and critically evaluate literature that was relevant. Results: The ET family consists of three isopeptides (ET-1, ET-2 and ET-3) that produce biological actions by acting on two types of receptors (ETA and ETB). In the central nervous system (CNS) ETA receptors are potent constrictors of the cerebral vasculature and appear to contribute in the causation of cerebral ischemia. ETA receptor antagonists have been found to be effective in animal model of cerebral ischemia; however, clinical studies have shown no efficacy. Mitochondrial functions are critically important for several neural development processes such as neurogenesis, axonal and dendritic growth, and synaptic formation. ET appears to impair mitochondrial functions through activation of ETA receptors. On the other hand, blocking ETB receptors has been shown to trigger apoptotic processes by activating intrinsic mitochondrial pathway. Mitochondria are important for their role in molecular regulation of neurogenesis and angiogenesis. Stimulation of ETB receptors in the adult ischemic brain has been found to promote angiogenesis and neurogenesis mediated through vascular endothelial growth factor and nerve growth factor. It will be interesting to investigate the effect of ETB receptor stimulation on mitochondrial functions in the CNS following cerebral ischemia. Conclusion: The findings of this

  17. Flow regulation of collecting duct endothelin-1 production.

    PubMed

    Lyon-Roberts, Brianna; Strait, Kevin A; van Peursem, Evan; Kittikulsuth, Wararat; Pollock, Jennifer S; Pollock, David M; Kohan, Donald E

    2011-03-01

    Collecting duct (CD) endothelin-1 (ET-1) is an important autocrine inhibitor of CD Na(+) reabsorption. Salt loading is thought to increase CD ET-1 production; however, definitive evidence of this, as well as understanding of the mechanisms transducing this effect, is lacking. Tubule fluid flow increases in response to Na(+) loading; hence, we studied flow modulation of CD ET-1 production. Three days of a high-salt diet increased mouse and rat inner medullary CD (IMCD) ET-1 mRNA expression. Acute furosemide infusion increased urinary ET-1 excretion in anesthetized rats. Primary cultures of mouse or rat IMCD detached in response to flow using a closed perfusion chamber, consequently a CD cell line (mpkCCDcl4) was examined. Flow increased ET-1 mRNA at shear stress rates exceeding 1 dyne/cm(2), with the maximal effect seen between 2 and 10 dyne/cm(2). Induction of ET-1 mRNA was first evident after 1 h, and most apparent after 2 h, of flow. Inhibition of calmodulin or dihydropyridine-sensitive Ca(2+) channels did not alter the flow response; however, chelation of intracellular Ca(2+) or removal of extracellular Ca(2+) largely prevented flow-stimulated ET-1 mRNA accumulation. Downregulation of protein kinase C (PKC) using phorbol 12-myristate 13-acetate, or PKC inhibition with calphostin C, markedly reduced flow-stimulated ET-1 mRNA levels. Flow-stimulated ET-1 mRNA accumulation was abolished by inhibition of phospholipase C (PLC). Taken together, these data indicate that flow increases CD ET-1 production and this is dependent on extracellular and intracellular Ca(2+), PKC, and PLC. These studies suggest a novel pathway for coupling alterations in extracellular fluid volume to CD ET-1 production and ultimately control of CD Na(+) reabsorption.

  18. Endothelin-induced contraction and mediator release in human bronchus.

    PubMed Central

    Hay, D. W.; Hubbard, W. C.; Undem, B. J.

    1993-01-01

    1. To elucidate the role of acetylcholine and various autacoids in endothelin-1 (ET-1)-induced contraction in human bronchus, the effects of various receptor antagonists were examined. In addition, the ability of ET-1 to stimulate the release of histamine, peptidoleukotrienes and prostanoids was determined. 2. ET-1 was a potent and effective contractile agonist in human bronchus, possessing similar potency and efficacy to leukotriene D4 (LTD4); EC50 (-log M): ET-1 = 7.76 +/- 0.09, n = 7; LTD4 = 8.46 +/- 0.53, n = 7; P > 0.2; maximum response (% 10 microM pre-carbachol): ET-1 = 103.8 +/- 17.4, n = 7; LTD4 = 95.5 +/- 9.3, n = 7; P > 0.6. 3. The cyclo-oxygenase inhibitor, sodium meclofenamate (1 microM) or the potent and selective thromboxane receptor antagonist, SQ 29,548 (1 microM) were without significant effect on ET-1 concentration-response curves. 4. In the presence of sodium meclofenamate (1 microM), the muscarinic receptor antagonist, atropine (1 microM), the platelet activating factor (PAF) receptor antagonist, WEB 2086 (1 microM) or the combination of the H1-histamine receptor antagonist, mepyramine (10 microM) and the leukotriene receptor antagonist, SK&F 104353 (10 microM), were without marked effect on ET-1 concentration-response curves. In addition, the combination of all four receptor antagonists did not antagonize ET-1-induced contraction. 5. ET-1 (0.3 microM) did not stimulate the release of histamine or immunoreactive leukotrienes from human bronchus.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7693285

  19. Elevated endothelin-1 expression in dogs with heartworm disease.

    PubMed

    Uchide, Tsuyoshi; Saida, Kaname

    2005-11-01

    We explored the involvement of endothelin-1 (ET-1) in the pathophysiology of dog dirofilariasis (heartworm disease caused by Dirofilaria immitis) by analyzing mRNA levels of preproendothelin-1 (PPET-1), the precursor form of ET-1, in cardiopulmonary organs as well as ET-1 peptide levels in plasma. To determine the cDNA sequence and primary protein structure of dog PPET-1, we performed molecular cloning of the full-length cDNA. Based on the determined sequence information, comparative expression analysis of PPET-1 mRNA was carried out by real-time polymerase chain reaction on cardiopulmonary organs from healthy (n=5) and filarial (n=5) dogs. Filarial dogs showed a significantly (p<0.05) higher mRNA expression level in the heart (about one hundred times) and lung (about ten times) than healthy dogs. Analysis of plasma ET-1 levels in healthy (n=10) and filarial (n=10) dogs showed that filarial dogs (6.9+/-2.7 pg/ml) have significantly (p<0.01) increased plasma ET-1 levels compared with healthy dogs (1.4+/-0.3 pg/ml). To assess the pathophysiological significance of ET-1 in dirofilariasis relative to other cardiopulmonary disorders, plasma ET-1 levels determined in dogs diagnosed with mitral regurgitation (n=10), tricuspid regurgitation (n=5), ventricular septal defect (n=5), and patent ductus arteriosus (n=5) were compared to plasma ET-1 levels in filarial dogs. Filarial dogs, which commonly develop serious pulmonary hypertension, exhibited by far the highest ET-1 levels of the disease states examined. Based on the fact that ET-1 is a potent bioactive mediator that induces vasoconstriction and promotes vascular remodeling, these findings suggest that ET-1 plays an important role in the pathophysiology of dog dirofilariasis as an aggravating factor by inducing pulmonary hypertension.

  20. Endothelin-converting enzyme 2 differentially regulates opioid receptor activity

    PubMed Central

    Gupta, A; Fujita, W; Gomes, I; Bobeck, E; Devi, L A

    2015-01-01

    BACKGROUND AND PURPOSE Opioid receptor function is modulated by post-activation events such as receptor endocytosis, recycling and/or degradation. While it is generally understood that the peptide ligand gets co-endocytosed with the receptor, relatively few studies have investigated the role of the endocytosed peptide and peptide processing enzymes in regulating receptor function. In this study, we focused on endothelin-converting enzyme 2 (ECE2), a member of the neprilysin family of metallopeptidases that exhibits an acidic pH optimum, localizes to an intracellular compartment and selectively processes neuropeptides including opioid peptides in vitro, and examined its role in modulating μ receptor recycling and resensitization. EXPERIMENTAL APPROACH The effect of ECE2 inhibition on hydrolysis of the endocytosed peptide was examined using thin-layer chromatography and on μ opioid receptor trafficking using either elisa or microscopy. The effect of ECE2 inhibition on receptor signalling was measured using a cAMP assay and, in vivo, on antinociception induced by intrathecally administered opioids by the tail-flick assay. KEY RESULTS The highly selective ECE2 inhibitor, S136492, significantly impaired μ receptor recycling and signalling by only those ligands that are ECE2 substrates and this was seen both in heterologous cells and in cells endogenously co-expressing μ receptors with ECE2. We also found that ECE2 inhibition attenuated antinociception mediated only by opioid peptides that are ECE2 substrates. CONCLUSIONS AND IMPLICATIONS These results suggest that ECE2, by selectively processing endogenous opioid peptides in the endocytic compartment, plays a role in modulating opioid receptor activity. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2 PMID:24990314

  1. Loss of the endothelin signal pathway in C6 rat glioma cells persistently infected with measles virus.

    PubMed Central

    Tas, P W; Koschel, K

    1991-01-01

    Endothelin 1 causes a strong Ca2+ signal in C6 rat glioma cells as measured by fura-2 fluorescence. This endothelin 1-induced Ca2+ signal was not observed when the cells were persistently infected with a measles virus strain of subacute sclerosing panencephalitis (SSPE, strain Lec). Binding of 125I-labeled endothelin 1 to the C6/SSPE cells was less than 5% of the binding to the C6 control cells, suggesting that the impairment in signal transduction was due to a loss of binding sites for endothelin 1. Treatment of the C6/SSPE cells with measles antiserum resulted in the loss of expression of viral proteins located in the membrane as well as inside the cells (antigenic modulation), but it restored neither the endothelin 1-induced Ca2+ rise nor the 125I-endothelin 1 binding. Cocultivation of uninfected C6 cells with C6/SSPE cells (9:1 ratio) resulting in contact-mediated transmission of measles virus showed that the 125I-endothelin 1 binding activity was gradually lost as a consequence of persistent virus infection. PMID:1650480

  2. Elevated Plasma Endothelin-1 Levels in Normal Tension Glaucoma and Primary Open-Angle Glaucoma: A Meta-Analysis

    PubMed Central

    Li, Shengjie; Zhang, Aiping

    2016-01-01

    Purpose. The aim of this meta-analysis was to clarify the association between the plasma endothelin-1 level and the risks of normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG). Methods. Relevant publications were collected from three databases including PubMed, EMBASE, and the Web of Science through December 31, 2015. In this study, the terms “(endothelin OR ET) AND glaucoma” were searched. Review Manager 5.2 was used to process the data. Results. Seven studies (212 cases, 164 controls) were included for the NTG analysis. The mean plasma endothelin-1 level in the NTG subjects was 0.60 pg/mL (p = 0.02, 95% CI: 0.17–1.04) higher than that of the healthy controls. Six studies (160 cases, 174 controls) were included for the POAG analysis, and the endothelin-1 level was 0.63 pg/mL (p = 0.007, 95% CI: 0.12–1.15) higher in the POAG subjects than in the healthy controls. Additionally, two studies influenced the meta-analysis results regarding the association of plasma endothelin-1 with POAG by sensitivity analysis, and the probability of publication bias was low. Conclusions. The observation that NTG and POAG subjects showed significantly elevated endothelin-1 plasma concentrations suggests that a higher plasma level of endothelin-1 might increase the risk of NTG and POAG development. PMID:27965889

  3. Effects of captopril on the renin angiotensin system, oxidative stress, and endothelin in normal and hypertensive rats.

    PubMed

    Bolterman, Rodney J; Manriquez, Melissa C; Ortiz Ruiz, M Clara; Juncos, Luis A; Romero, J Carlos

    2005-10-01

    There is substantial evidence suggesting that angiotensin II plays an important role in elevating blood pressure of spontaneously hypertensive rats, despite normal plasma renin activity, and that converting enzyme inhibitors (captopril) can effectively normalize blood pressure in the spontaneously hypertensive rats. One mechanism by which angiotensin II induces hypertension is via oxidative stress and endothelin, as seen in subpressor angiotensin II-induced hypertension. In fact, it has been shown that antioxidants lower mean arterial pressure in spontaneously hypertensive rats. However, the relationship between angiotensin II, oxidative stress, and endothelin in the spontaneously hypertensive rats is still relatively undefined. This study examines the relationship between mean arterial pressure, plasma renin activity, angiotensin II, oxidative stress, and endothelin in spontaneously hypertensive rats compared with normotensive Wistar Kyoto rats, and the effects of captopril on this association. Untreated spontaneously hypertensive rats had increased plasma angiotensin II levels despite normal plasma renin activity, oxidative stress, and endothelin. Captopril treatment in spontaneously hypertensive rats lowered mean arterial pressure, angiotensin II, oxidative stress, and endothelin, and increased plasma renin activity. In contrast, captopril increased plasma renin activity (suggesting effective captopril treatment) but did not significantly alter mean arterial pressure, angiotensin II, oxidative stress, or endothelin of Wistar Kyoto rats. These results suggest that in spontaneously hypertensive rats, angiotensin II is a primary instigator of hypertension, and that captopril selectively lowers angiotensin II, oxidant stress, and endothelin, which in turn may contribute to the blood pressure-lowering efficacy of captopril in spontaneously hypertensive rats.

  4. Combined TRPC3 and TRPC6 blockade by selective small-molecule or genetic deletion inhibits pathological cardiac hypertrophy

    PubMed Central

    Seo, Kinya; Rainer, Peter P.; Shalkey Hahn, Virginia; Lee, Dong-ik; Jo, Su-Hyun; Andersen, Asger; Liu, Ting; Xu, Xiaoping; Willette, Robert N.; Lepore, John J.; Marino, Joseph P.; Birnbaumer, Lutz; Schnackenberg, Christine G.; Kass, David A.

    2014-01-01

    Chronic neurohormonal and mechanical stresses are central features of heart disease. Increasing evidence supports a role for the transient receptor potential canonical channels TRPC3 and TRPC6 in this pathophysiology. Channel expression for both is normally very low but is increased by cardiac disease, and genetic gain- or loss-of-function studies support contributions to hypertrophy and dysfunction. Selective small-molecule inhibitors remain scarce, and none target both channels, which may be useful given the high homology among them and evidence of redundant signaling. Here we tested selective TRPC3/6 antagonists (GSK2332255B and GSK2833503A; IC50, 3–21 nM against TRPC3 and TRPC6) and found dose-dependent blockade of cell hypertrophy signaling triggered by angiotensin II or endothelin-1 in HEK293T cells as well as in neonatal and adult cardiac myocytes. In vivo efficacy in mice and rats was greatly limited by rapid metabolism and high protein binding, although antifibrotic effects with pressure overload were observed. Intriguingly, although gene deletion of TRPC3 or TRPC6 alone did not protect against hypertrophy or dysfunction from pressure overload, combined deletion was protective, supporting the value of dual inhibition. Further development of this pharmaceutical class may yield a useful therapeutic agent for heart disease management. PMID:24453217

  5. Modulation of vascular tone by endothelin-1: role of preload, endothelial integrity and concentration of endothelin-1.

    PubMed Central

    Mehta, J. L.; Lawson, D. L.; Yang, B. C.; Mehta, P.; Nichols, W. W.

    1992-01-01

    1. Endothelin-1 (ET-1) has been shown to exert both arterial relaxant and constrictor effects. To examine the mechanisms of these divergent effects, rat aortic rings were suspended in an organ bath (baseline preload, 5 g) and exposed to ET-1 (10(-11) to 10(-7) M). ET-1 contracted these rings in a concentration-dependent fashion. 2. When aortic rings were contracted with noradrenaline (NA) to 1 g of tension, ET-1 caused further contraction of these rings. In rings precontracted to 2 to 4 g of tension, low concentrations of ET-1 (10(-11) to 10(-9) M) caused a significant relaxation, but high concentrations (greater than or equal to 5 x 10(-9) M) caused a marked contraction, indicating both relaxant and contractile effects of ET-1 depending on the preload and ET-1 concentration. 3. To determine the mechanism of ET-1-induced relaxation, aortic rings were pretreated with the cyclo-oxygenase inhibitor indomethacin, NG-monomethyl-L-arginine (L-NMMA) an inhibitor of synthesis of endothelium-derived relaxing factor (EDRF), or oxyhaemoglobin (Hb) which decreases the activity of EDRF, prior to their exposure to ET-1. Both indomethacin and L-NMMA markedly (P less than 0.01) attenuated ET-1-induced relaxation, whereas Hb totally abolished it. Removal of the endothelium from aortic rings also abolished ET-1-mediated relaxation. 4. The relaxant effect of ET-1 in NA-precontracted rings was associated with marked accumulation of guanosine 3':5'-cyclic monophosphate (cyclic GMP), whereas ET-1-induced contraction of quiescent rings was not. 5.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1324065

  6. Bosentan, a mixed endothelin receptor antagonist, induces antidepressant-like activity in mice.

    PubMed

    Pinho-Ribeiro, Felipe A; Borghi, Sergio M; Staurengo-Ferrari, Larissa; Filgueiras, Guilherme B; Estanislau, Célio; Verri, Waldiceu A

    2014-02-07

    Endothelins are peptides described initially as potent vasoactive mediators. Recently, studies reported that endothelins can modulate the production and release of cytokines by immune cells. In turn, cytokines are involved in depression disorders and also in the effectiveness of some antidepressants. Therefore, we investigated the effects of treating mice with bosentan, a mixed endothelin receptor antagonist, in widely used models for assessing antidepressant activity of compounds, the forced swimming (FST) and the tail suspension tests (TST). Moreover, the influence of bosentan treatment on circulating IL-6 levels was also addressed after FST. The results show that bosentan treatment induced a bell shaped dose-dependent antidepressant-like effect with increase in circulating IL-6 levels in animals exposed to FST. Bosentan also presented antidepressant-like effect in TST. Similar results were obtained with nortriptyline treatment in the FST and TST. Possible anxiogenic effect of bosentan was excluded using the elevated plus maze test. Therefore, this is the first study to demonstrate the antidepressant-like activity of bosentan in mice, unveiling a previous unrecognized role of endothelin in depression and its possible relation with increased circulating IL-6 levels.

  7. The Endothelin System Has a Significant Role in the Pathogenesis and Progression of Mycobacterium tuberculosis Infection

    PubMed Central

    Correa, Andre F.; Bailão, Alexandre M.; Bastos, Izabela M. D.; Orme, Ian M.; Soares, Célia M. A.; Kipnis, Andre

    2014-01-01

    Tuberculosis (TB) remains a major global health problem, and although multiple studies have addressed the relationship between Mycobacterium tuberculosis and the host on an immunological level, few studies have addressed the impact of host physiological responses. Proteases produced by bacteria have been associated with important alterations in the host tissues, and a limited number of these enzymes have been characterized in mycobacterial species. M. tuberculosis produces a protease called Zmp1, which appears to be associated with virulence and has a putative action as an endothelin-converting enzyme. Endothelins are a family of vasoactive peptides, of which 3 distinct isoforms exist, and endothelin 1 (ET-1) is the most abundant and the best-characterized isoform. The aim of this work was to characterize the Zmp1 protease and evaluate its role in pathogenicity. Here, we have shown that M. tuberculosis produces and secretes an enzyme with ET-1 cleavage activity. These data demonstrate a possible role of Zmp1 for mycobacterium-host interactions and highlights its potential as a drug target. Moreover, the results suggest that endothelin pathways have a role in the pathogenesis of M. tuberculosis infections, and ETA or ETB receptor signaling can modulate the host response to the infection. We hypothesize that a balance between Zmp1 control of ET-1 levels and ETA/ETB signaling can allow M. tuberculosis adaptation and survival in the lung tissues. PMID:25267836

  8. Murine study of portal hypertension associated endothelin-1 hypo-response

    PubMed Central

    Theodorakis, Nicholas; Maluccio, Mary; Skill, Nicholas

    2015-01-01

    AIM: To investigate endothelin-1 hypo-responsive associated with portal hypertension in order to improve patient treatment outcomes. METHODS: Wild type, eNOS-/- and iNOS-/- mice received partial portal vein ligation surgery to induce portal hypertension or sham surgery. Development of portal hypertension was determined by measuring the splenic pulp pressure, abdominal aortic flow and portal systemic shunting. To measure splenic pulp pressure, a microtip pressure transducer was inserted into the spleen pulp. Abdominal aortic flow was measured by placing an ultrasonic Doppler flow probe around the abdominal aorta between the diaphragm and celiac artery. Portal systemic shunting was calculated by injection of fluorescent microspheres in to the splenic vein and determining the percentage accumulation of spheres in liver and pulmonary beds. Endothelin-1 hypo-response was evaluated by measuring the change in abdominal aortic flow in response to endothelin-1 intravenous administration. In addition, thoracic aorta endothelin-1 contraction was measured in 5 mm isolated thoracic aorta rings ex-vivo using an ADI small vessel myograph. RESULTS: In wild type and iNOS-/- mice splenic pulp pressure increased from 7.5 ± 1.1 mmHg and 7.2 ± 1 mmHg to 25.4 ± 3.1 mmHg and 22 ± 4 mmHg respectively. In eNOS-/- mice splenic pulp pressure was increased after 1 d (P = NS), after which it decreased and by 7 d was not significantly elevated when compared to 7 d sham operated controls (6.9 ± 0.6 mmHg and 7.3 ± 0.8 mmHg respectively, P = 0.3). Abdominal aortic flow was increased by 80% and 73% in 7 d portal vein ligated wild type and iNOS when compared to shams, whereas there was no significant difference in 7 d portal vein ligated eNOS-/- mice when compared to shams. Endothelin-1 induced a rapid reduction in abdominal aortic blood flow in wild type, eNOS-/- and iNOS-/- sham mice (50% ± 8%, 73% ± 9% and 47% ± 9% respectively). Following portal vein ligation endothelin-1 reduction in

  9. Horizon 2020 in Diabetic Kidney Disease: The Clinical Trial Pipeline for Add-On Therapies on Top of Renin Angiotensin System Blockade

    PubMed Central

    Perez-Gomez, Maria Vanessa; Sanchez-Niño, Maria Dolores; Sanz, Ana Belen; Martín-Cleary, Catalina; Ruiz-Ortega, Marta; Egido, Jesus; Navarro-González, Juan F.; Ortiz, Alberto; Fernandez-Fernandez, Beatriz

    2015-01-01

    Diabetic kidney disease is the most frequent cause of end-stage renal disease. This implies failure of current therapeutic approaches based on renin-angiotensin system (RAS) blockade. Recent phase 3 clinical trials of paricalcitol in early diabetic kidney disease and bardoxolone methyl in advanced diabetic kidney disease failed to meet the primary endpoint or terminated on safety concerns, respectively. However, various novel strategies are undergoing phase 2 and 3 randomized controlled trials targeting inflammation, fibrosis and signaling pathways. Among agents currently undergoing trials that may modify the clinical practice on top of RAS blockade in a 5-year horizon, anti-inflammatory agents currently hold the most promise while anti-fibrotic agents have so far disappointed. Pentoxifylline, an anti-inflammatory agent already in clinical use, was recently reported to delay estimated glomerular filtration rate (eGFR) loss in chronic kidney disease (CKD) stage 3–4 diabetic kidney disease when associated with RAS blockade and promising phase 2 data are available for the pentoxifylline derivative CTP-499. Among agents targeting chemokines or chemokine receptors, the oral small molecule C-C chemokine receptor type 2 (CCR2) inhibitor CCX140 decreased albuminuria and eGFR loss in phase 2 trials. A dose-finding trial of the anti-IL-1β antibody gevokizumab in diabetic kidney disease will start in 2015. However, clinical development is most advanced for the endothelin receptor A blocker atrasentan, which is undergoing a phase 3 trial with a primary outcome of preserving eGFR. The potential for success of these approaches and other pipeline agents is discussed in detail. PMID:26239562

  10. Optimal Photon Blockade on the Maximal Atomic Coherence

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Zhang, Jun; Yu, Chang-shui

    2016-12-01

    There is generally no obvious evidence in any direct relation between photon blockade and atomic coherence. Here instead of only illustrating the photon statistics, we show an interesting relation between the steady-state photon blockade and the atomic coherence by designing a weakly driven cavity QED system with a two-level atom trapped. It is shown for the first time that the maximal atomic coherence has a perfect correspondence with the optimal photon blockade. The negative effects of the strong dissipations on photon statistics, atomic coherence and their correspondence are also addressed. The numerical simulation is also given to support all of our results.

  11. Activity blockade and GABAA receptor blockade produce synaptic scaling through chloride accumulation in embryonic spinal motoneurons and interneurons.

    PubMed

    Lindsly, Casie; Gonzalez-Islas, Carlos; Wenner, Peter

    2014-01-01

    Synaptic scaling represents a process whereby the distribution of a cell's synaptic strengths are altered by a multiplicative scaling factor. Scaling is thought to be a compensatory response that homeostatically controls spiking activity levels in the cell or network. Previously, we observed GABAergic synaptic scaling in embryonic spinal motoneurons following in vivo blockade of either spiking activity or GABAA receptors (GABAARs). We had determined that activity blockade triggered upward GABAergic scaling through chloride accumulation, thus increasing the driving force for these currents. To determine whether chloride accumulation also underlies GABAergic scaling following GABAAR blockade we have developed a new technique. We expressed a genetically encoded chloride-indicator, Clomeleon, in the embryonic chick spinal cord, which provides a non-invasive fast measure of intracellular chloride. Using this technique we now show that chloride accumulation underlies GABAergic scaling following blockade of either spiking activity or the GABAAR. The finding that GABAAR blockade and activity blockade trigger scaling via a common mechanism supports our hypothesis that activity blockade reduces GABAAR activation, which triggers synaptic scaling. In addition, Clomeleon imaging demonstrated the time course and widespread nature of GABAergic scaling through chloride accumulation, as it was also observed in spinal interneurons. This suggests that homeostatic scaling via chloride accumulation is a common feature in many neuronal classes within the embryonic spinal cord and opens the possibility that this process may occur throughout the nervous system at early stages of development.

  12. Effects of age and caloric restriction in the vascular response of renal arteries to endothelin-1 in rats.

    PubMed

    Amor, Sara; García-Villalón, Angel Luis; Rubio, Carmen; Carrascosa, Jose Ma; Monge, Luis; Fernández, Nuria; Martín-Carro, Beatriz; Granado, Miriam

    2017-02-01

    Cardiovascular alterations are the most prevalent cause of impaired physiological function in aged individuals with kidney being one the most affected organs. Aging-induced alterations in renal circulation are associated with a decrease in endothelium-derived relaxing factors such as nitric oxide (NO) and with an increase in contracting factors such as endothelin-1(ET-1). As caloric restriction (CR) exerts beneficial effects preventing some of the aging-induced alterations in cardiovascular system, the aim of this study was to analyze the effects of age and caloric restriction in the vascular response of renal arteries to ET-1 in aged rats. Vascular function was studied in renal arteries from 3-month-old Wistar rats fed ad libitum (3m) and in renal arteries from 8-and 24-month-old Wistar rats fed ad libitum (8m and 24m), or subjected to 20% caloric restriction during their three last months of life (8m-CR and 24m-CR). The contractile response to ET-1 was increased in renal arteries from 8m and 24m compared to 3m rats. ET-1-induced contraction was mediated by ET-A receptors in all experimental groups and also by ET-B receptors in 24m rats. Caloric restriction attenuated the increased contraction to ET-1 in renal arteries from 8m but not from 24m rats possibly through NO release proceeding from ET-B endothelial receptors. In 24m rats, CR did not attenuate the aging-increased response of renal arteries to ET-1, but it prevented the aging-induced increase in iNOS mRNA levels and the aging-induced decrease in eNOS mRNA levels in arterial tissue. In conclusion, aging is associated with an increased response to ET-1 in renal arteries that is prevented by CR in 8m but not in 24m rats.

  13. Green tea extract inhibits paraquat-induced pulmonary fibrosis by suppression of oxidative stress and endothelin-l expression.

    PubMed

    Kim, Hak-Ryul; Park, Byung-Kyu; Oh, Yeon-Mok; Lee, Yun-Song; Lee, Dong-Soon; Kim, Hyun-Kuk; Kim, Joo-Young; Shim, Tae-Sun; Lee, Sang-Do

    2006-01-01

    Paraquat-induced pulmonary fibrosis involves two factors, direct injury by oxygen free radicals and indirect injury by inflammatory cells and fibroblasts. Endothelin-1 (ET-1) has been shown to act as a mediator of pulmonary fibrosis, and its formation increases during oxidative stress. We investigated whether green tea extract (GTE), which has antioxidant properties, inhibits paraquat-induced pulmonary fibrosis and whether ET-1 is involved in this process. Paraquat (0.3 mg/kg) was instilled into the right lungs of rats, following which the rats were either not further treated (Group P, n = 7), or they were administered 1% GTE mixed with feed (Group PG; n = 7) or the ET(A) receptor antagonist ZD2574 (10 mg/kg through gavage; Group PZ; n = 7) for two weeks. As control, we used rats instilled with saline (Group N; n = 6). Two weeks after paraquat instillation, we assayed the degree of pulmonary fibrosis by light microscopic morphometry and hydroxyproline content; lipid peroxidation as a marker of oxidative stresses by measurement of malondialdehyde (MDA); ET-1 by immunohistochemistry; and prepro-ET-1 mRNA expression by reverse transcription-polymerase chain reaction. Compared with Group N, significant pulmonary fibrosis was observed in Group P, accompanied by increases in MDA, ET-1, and prepro-ET-1 mRNA expression. Compared with Group P, Group PG showed significant decreases in pulmonary fibrosis, along with decreases in MDA, ET-1, and prepro-ET-1 mRNA expression. We also observed significant decreases in pulmonary fibrosis in Group PZ compared with Group P. These findings suggest that GTE inhibits paraquat-induced pulmonary fibrosis by suppression of oxidative stress and ET-1 expression.

  14. Characterizing the role of endothelin-1 in the progression of cardiac hypertrophy in aryl hydrocarbon receptor (AhR) null mice

    SciTech Connect

    Lund, Amie K.; Goens, M. Beth; Nunez, Bethany A.; Walker, Mary K. . E-mail: mkwalker@unm.edu

    2006-04-15

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor characterized to play a role in detection and adaptation to environmental stimuli. Genetic deletion of AhR results in hypertension, and cardiac hypertrophy and fibrosis, associated with elevated plasma angiotensin II (Ang II) and endothelin-1 (ET-1), thus AhR appears to contribute to cardiovascular homeostasis. In these studies, we tested the hypothesis that ET-1 mediates cardiovascular pathology in AhR null mice via ET{sub A} receptor activation. First, we determine the time courses of cardiac hypertrophy, and of plasma and tissue ET-1 expression in AhR wildtype and null mice. AhR null mice exhibited increases in heart-to-body weight ratio and age-related expression of cardiac hypertrophy markers, {beta}-myosin heavy chain ({beta}-MHC), and atrial natriuretic factor (ANF), which were significant at 2 months. Similarly, plasma and tissue ET-1 expression was significantly elevated at 2 months and increased further with age. Second, AhR null mice were treated with ET{sub A} receptor antagonist, BQ-123 (100 nmol/kg/day), for 7, 28, or 58 days and blood pressure, cardiac fibrosis, and cardiac hypertrophy assessed, respectively. BQ-123 for 7 days significantly reduced mean arterial pressure in conscious, catheterized mice. BQ-123 for 28 days significantly reduced the histological appearance of cardiac fibrosis. Treatment for 58 days significantly reduced cardiac mass, assessed by heart weight, echocardiography, and {beta}-MHC and ANF expression; and reduced cardiac fibrosis as determined by osteopontin and collagen I mRNA expression. These findings establish ET-1 and the ET{sub A} receptor as primary determinants of hypertension and cardiac pathology in AhR null mice.

  15. Rydberg blockade effects at n ˜300 in strontium

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Dunning, F. B.; Yoshida, S.; Burgdörfer, J.

    2015-11-01

    Rydberg blockade at n ˜300 , is examined using strontium n F13 Rydberg atoms excited in an atomic beam in a small volume defined by two tightly focused crossed laser beams. The observation of blockade for such states is challenging due to their extreme sensitivity to stray fields and the many magnetic sublevels associated with F states which results in a high local density of states. Nonetheless, with a careful choice of laser polarization to selectively excite only a limited number of these sublevels, sizable blockade effects are observed on an ˜0.1 mm length scale extending blockade measurements into the near-macroscopic regime and enabling study of the dynamics of strongly coupled many-body high-n Rydberg systems under carefully controlled conditions.

  16. Blockade involving high- n, n ~ 300 , strontium Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Yoshida, Shuhei; Burgdörfer, Joachim; Zhang, Xinyue; Dunning, F. Barry

    2016-05-01

    The blockade of high- n strontium n1F3 Rydberg states contained in a hot atomic beam is investigated both theoretically and experimentally. One difficulty in such experiments is that, once created, Rydberg atoms move out of the excitation volume reducing blockade effects. While the effects of such motion are apparent, the data provide strong evidence of blockade, consistent with theoretical predictions. Because of their relatively high angular momentum (L = 3) , a pair of n1F3 Rydberg atoms have many degenerate states whose degeneracy is removed by Rydberg-Rydberg interactions yielding a high density of states near the target energy. To evaluate the effect of blockade not only the energy shifts but also the modification of the oscillator strengths for excitation have to be taken into account. The n-scaling of the interactions and the importance of high-order multipoles will also be discussed. Research supported by the NSF and Robert A. Welch Foundation.

  17. Selective relaxant binding agents for reversal of neuromuscular blockade.

    PubMed

    Bom, Anton; Epemolu, Ola; Hope, Frank; Rutherford, Samantha; Thomson, Karen

    2007-06-01

    Traditionally, reversal of neuromuscular blockade during anaesthesia was achieved by increasing the acetylcholine concentration in the neuromuscular junction using acetylcholinesterase inhibitors. However, this is ineffective against profound blockade. Furthermore, the increase in acetylcholine level is not limited to the neuromuscular junction, resulting in unwanted side effects requiring co-treatment with muscarinic antagonists. Selective relaxant binding agents offer a new approach for the reversal of neuromuscular blockade: encapsulation of the neuromuscular blocking agent, resulting in inactivation. As part of this new approach, cyclodextrin molecules have been designed that selectively encapsulate steroidal neuromuscular blocking agents. Both animal and human experiments have demonstrated that fast, effective and complete recovery from both normal and profound neuromuscular blockade is now possible. Furthermore, these cyclodextrin derivatives do not have the unwanted side effects of acetylcholinesterase inhibitors.

  18. Radiotherapy and immune checkpoint blockades: a snapshot in 2016

    PubMed Central

    Koo, Taeryool; Kim, In Ah

    2016-01-01

    Immune checkpoint blockades including monoclonal antibodies (mAbs) of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1) have been emerged as a promising anticancer therapy. Several immune checkpoint blockades have been approved by US Food and Drug Administration (FDA), and have shown notable success in clinical trials for patients with advanced melanoma and non-small cell lung cancer. Radiotherapy is a promising combination partner of immune checkpoint blockades due to its potent pro-immune effect. This review will cover the current issue and the future perspectives for combined with radiotherapy and immune checkpoint blockades based upon the available preclinical and clinical data. PMID:28030901

  19. Effects of a new dihydropyridine derivative, S12968 (pranedipine), and its stereoisomer, S12967, on renal effects of endothelin-1.

    PubMed

    Montañés, I; Flores, O; Eleno, N; López-Novoa, J M

    1994-11-01

    The purpose of the present study was to assess in rats the prevention by two enantiomers of a new dihydropyridine derivative (pranedipine) (called S12967 for the dextrogyre (+) and S12968 for the levogyre (-) molecules) of the renal and cardiovascular effects induced by endothelin-1. The injection of endothelin-1 (1 nmol/kg body weight) induced a sharp and transient decrease in urine flow, sodium and potassium excretion, glomerular filtration rate, renal plasma flow, and renal blood flow, a significant increase in renal vascular resistance, and a small but significant increase in arterial pressure. Treatment with S12968 alone (0.3 mg/kg) induced a 2.5-fold increase in urine flow and potassium excretion and a 4.5-fold increase in sodium excretion. Pretreatment with S12968 completely blocked the endothelin-1 induced increase in arterial pressure, did not affect the acute effect of endothelin-1 on urine flow, sodium and potassium excretion, filtration rate, and renal blood flow, but blunted the effect on renal vascular resistance. Administration of S12967 alone (1 mg/kg) did not induce changes in either renal function or arterial pressure. In S12967-treated animals, endothelin-1 also induced a transient increase in arterial pressure nad renal vascular resistance but failed to change renal function in a significant manner. In summary, the above reported experiments show that at the higher, nonhypotensive doses, the levogyre enantiomer (S12968) of a new dihydropyridine derivative (pranedipine) completely prevented the hypertensive effect of endothelin 1, and partially prevented the effect of endothelin-1 on renal vascular resistance. The dextrogyre enantiomer (S12967) had almost no effect on either mean arterial pressure or renal vascular resistance but completely blocked the endothelin-1-induced decrease in urine flow and urinary sodium excretion.

  20. Costimulation Blockade in Kidney Transplantation: An Update

    PubMed Central

    Malvezzi, Paolo; Jouve, Thomas; Rostaing, Lionel

    2016-01-01

    Abstract In the setting of solid-organ transplantation, calcineurin inhibitor (CNI)-based therapy remains the cornerstone of immunosuppression. However, long-term use of CNIs is associated with some degree of nephrotoxicity. This has led to exploring the blockade of some costimulation pathways as an efficient immunosuppressive tool instead of using CNIs. The only agent already in clinical use and approved by the health authorities for kidney transplant patients is belatacept (Nulojix), a fusion protein that interferes with cytotoxic T lymphocyte-associated protein 4. Belatacept has been demonstrated to be as efficient as cyclosporine-based immunosuppression and is associated with significantly better renal function, that is, no nephrotoxicity. However, in the immediate posttransplant period, significantly more mild/moderate episodes of acute rejection have been reported, favored by the fact that cytotoxic T lymphocyte-associated protein pathway has an inhibitory effect on the alloimmune response; thereby its inhibition is detrimental in this regard. This has led to the development of antibodies that target CD28. The most advanced is FR104, it has shown promise in nonhuman primate models of autoimmune diseases and allotransplantation. In addition, research into blocking the CD40-CD154 pathway is underway. A phase II study testing ASK1240, that is, anti-CD40 antibody has been completed, and the results are pending. PMID:27472094

  1. Interleukin-6 blockade in ocular inflammatory diseases

    PubMed Central

    Mesquida, M; Leszczynska, A; Llorenç, V; Adán, A

    2014-01-01

    Interleukin-6 (IL-6) is a key cytokine featuring redundancy and pleiotropic activity. It plays a central role in host defence against environmental stress such as infection and injury. Dysregulated, persistent interleukin (IL)-6 production has been implicated in the development of various autoimmune, chronic inflammatory diseases and even cancers. Significant elevation of IL-6 has been found in ocular fluids derived from refractory/chronic uveitis patients. In experimental autoimmune uveitis models with IL-6 knock-out mice, IL-6 has shown to be essential for inducing inflammation. IL-6 blockade can suppress acute T helper type 17 (Th17) responses via its differentiation and, importantly, can ameliorate chronic inflammation. Tocilizumab, a recombinant humanized anti-IL-6 receptor antibody, has been shown to be effective in several autoimmune diseases, including uveitis. Herein, we discuss the basic biology of IL-6 and its role in development of autoimmune conditions, focusing particularly on non-infectious uveitis. It also provides an overview of efficacy and safety of tocilizumab therapy for ocular inflammatory diseases. PMID:24528300

  2. Sarafotoxin S6c is a relatively weak displacer of specifically bound /sup 125/I-endothelin

    SciTech Connect

    Nayler, W.G.; Gu, X.H.; Casley, D.J.

    1989-05-30

    Sarafotoxin S6a, S6b and S6c are chemically related vasoconstrictor polypeptides obtained from the venom of the snake, Atractaspis engaddensis. Each contains twenty one amino acid residues, two intrachain cysteine linkages and a long hydrophobic tail. Structurally these polypeptides resemble endothelin. Binding studies with /sup 125/I-endothelin showed that /sup 125/I-endothelin bound to rat ventricular membranes is totally displaceable by sarafotoxin S6b and endothelin, with IC50 values of 0.21 and 0.16 nM, respectively. Sarafotoxin S6c, which differs from sarafotoxin S6b in containing threonine instead of serine at residue 2, arginine instead of lysine at residue 4, and glutamic acid instead of lysine at residue 9, only weakly displaced bound /sup 125/I-endothelin (IC50, 854 nM). These results indicate that the ability of the sarafotoxins to interact with the endothelin binding site is not solely dependent on the long hydrophobic tail or the cysteine linkages.

  3. Orbital excitation blockade and algorithmic cooling in quantum gases.

    PubMed

    Bakr, Waseem S; Preiss, Philipp M; Tai, M Eric; Ma, Ruichao; Simon, Jonathan; Greiner, Markus

    2011-12-21

    Interaction blockade occurs when strong interactions in a confined, few-body system prevent a particle from occupying an otherwise accessible quantum state. Blockade phenomena reveal the underlying granular nature of quantum systems and allow for the detection and manipulation of the constituent particles, be they electrons, spins, atoms or photons. Applications include single-electron transistors based on electronic Coulomb blockade and quantum logic gates in Rydberg atoms. Here we report a form of interaction blockade that occurs when transferring ultracold atoms between orbitals in an optical lattice. We call this orbital excitation blockade (OEB). In this system, atoms at the same lattice site undergo coherent collisions described by a contact interaction whose strength depends strongly on the orbital wavefunctions of the atoms. We induce coherent orbital excitations by modulating the lattice depth, and observe staircase-like excitation behaviour as we cross the interaction-split resonances by tuning the modulation frequency. As an application of OEB, we demonstrate algorithmic cooling of quantum gases: a sequence of reversible OEB-based quantum operations isolates the entropy in one part of the system and then an irreversible step removes the entropy from the gas. This technique may make it possible to cool quantum gases to have the ultralow entropies required for quantum simulation of strongly correlated electron systems. In addition, the close analogy between OEB and dipole blockade in Rydberg atoms provides a plan for the implementation of two-quantum-bit gates in a quantum computing architecture with natural scalability.

  4. Constitutive ALK5-Independent c-Jun N-Terminal Kinase Activation Contributes to Endothelin-1 Overexpression in Pulmonary Fibrosis: Evidence of an Autocrine Endothelin Loop Operating through the Endothelin A and B Receptors

    PubMed Central

    Shi-Wen, Xu; Rodríguez-Pascual, Fernando; Lamas, Santiago; Holmes, Alan; Howat, Sarah; Pearson, Jeremy D.; Dashwood, Michael R.; du Bois, Roland M.; Denton, Christopher P.; Black, Carol M.; Abraham, David J.; Leask, Andrew

    2006-01-01

    The signal transduction mechanisms generating pathological fibrosis are almost wholly unknown. Endothelin-1 (ET-1), which is up-regulated during tissue repair and fibrosis, induces lung fibroblasts to produce and contract extracellular matrix. Lung fibroblasts isolated from scleroderma patients with chronic pulmonary fibrosis produce elevated levels of ET-1, which contribute to the persistent fibrotic phenotype of these cells. Transforming growth factor β (TGF-β) induces fibroblasts to produce and contract matrix. In this report, we show that TGF-β induces ET-1 in normal and fibrotic lung fibroblasts in a Smad-independent ALK5/c-Jun N-terminal kinase (JNK)/Ap-1-dependent fashion. ET-1 induces JNK through TAK1. Fibrotic lung fibroblasts display constitutive JNK activation, which was reduced by the dual ETA/ETB receptor inhibitor, bosentan, providing evidence of an autocrine endothelin loop. Thus, ET-1 and TGF-β are likely to cooperate in the pathogenesis of pulmonary fibrosis. As elevated JNK activation in fibrotic lung fibroblasts contributes to the persistence of the myofibroblast phenotype in pulmonary fibrosis by promoting an autocrine ET-1 loop, targeting the ETA and ETB receptors or constitutive JNK activation by fibrotic lung fibroblasts is likely to be of benefit in combating chronic pulmonary fibrosis. PMID:16809784

  5. Functions, dysfunctions and possible therapeutic relevance of adenosine A2A receptors in Huntington's disease.

    PubMed

    Popoli, Patrizia; Blum, David; Martire, Alberto; Ledent, Catherine; Ceruti, Stefania; Abbracchio, Maria P

    2007-04-01

    The aim of this review is to summarize and critically discuss the complex role played by adenosine A(2A) receptors (A(2A)Rs) in Huntington's disease (HD). Since A(2A)Rs are mainly localized on the neurons, which degenerate early in HD, and given their ability to stimulate glutamate outflow and inflammatory gliosis, it was hypothesized that they could be involved in the pathogenesis of HD, and that A(2A)R antagonists could be neuroprotective. This was further sustained by the demonstration that A(2A)Rs and underlying signaling systems undergo profound changes in cellular and animal models of HD. More recently, however, the equation A(2A) receptor blockade=neuroprotection has appeared too simplistic. First, it is now definitely clear that, besides mediating 'bad' responses (for example, stimulation of glutamate outflow and excessive glial activation), A(2A)Rs also promote 'good' responses (such as trophic and antinflammatory effects). This implies that A(2A)R blockade results either in pro-toxic or neuroprotective effects according to the mechanisms involved in a given experimental model. Second, since HD is a chronically progressive disease, the multiple mechanisms involving A(2A)Rs may play different relative roles along the degenerative process. Such different mechanisms can be influenced by A(2A)R activation or blockade in different ways, even leading to opposite outcomes depending on the time of agonist/antagonist administration. The number, and the complexity, of the possible scenarios is further increased by the influence of mutant Huntingtin on both the expression and functions of A(2A)Rs, and by the strikingly different effects mediated by A(2A)Rs expressed by different cell populations within the brain.

  6. 5-HT2A receptors control body temperature in mice during LPS-induced inflammation via regulation of NO production.

    PubMed

    Voronova, Irina P; Khramova, Galina M; Kulikova, Elizabeth A; Petrovskii, Dmitrii V; Bazovkina, Daria V; Kulikov, Alexander V

    2016-01-01

    G protein-coupled 5-HT2A receptors are involved in the regulation of numerous normal and pathological physiological functions. At the same time, its involvement in the regulation of body temperature (Tb) in normal conditions is obscure. Here we study the effect of the 5-HT2A receptor activation or blockade on Tb in sick animals. The experiments were carried out on adult C57BL/6 mouse males. Systemic inflammation and sickness were produced by lipopolysaccharide (LPS, 0.1mg/kg, ip), while the 5-HT2A receptor was stimulated or blocked through the administration of the receptor agonist DOI or antagonist ketanserin (1mg/kg), respectively. LPS, DOI or ketanserin alone produced no effect on Tb. However, administration of LPS together with a peripheral or central ketanserin injection reduced Tb (32.2°C). Ketanserin reversed the LPS-induced expression of inducible NO synthase in the brain. Consequently, an involvement of NO in the mechanism of the hypothermic effect of ketanserin in sick mice was hypothesized. Administration of LPS together with NO synthase inhibitor, l-nitro-arginine methyl ester (60mg/kg, ip) resulted in deep (28.5°C) and prolonged (8h) hypothermia, while administration of l-nitro-arginine methyl ester alone produced no effect on Tb. Thus, 5-HT2A receptors play a key role in Tb control in sick mice. Blockade of this GPCR produces hypothermia in mice with systemic inflammation via attenuation of LPS-induced NO production. These results indicate an unexpected role of 5-HT2A receptors in inflammation and NO production and have a considerable biological impact on understanding the mechanism of animal adaptation to pathogens and parasites. Moreover, adverse side effects of 5-HT2A receptor antagonists in patients with inflammation may be expected.

  7. Endothelins in the cat petrosal ganglion and carotid body: effects and immunolocalization.

    PubMed

    Rey, Sergio; Del Rio, Rodrigo; Alcayaga, Julio; Iturriaga, Rodrigo

    2006-01-19

    In response to hypoxia, chemoreceptor cells of the carotid body (CB) release transmitters, which acting on the petrosal ganglion (PG) neuron terminals, increase the chemoafferent discharge. Additionally, vasoactive molecules produced within the CB may modulate hypoxic chemoreception by controlling blood flow and tissue PO2. Endothelin-1 (ET-1) increases basal CB chemosensory discharges in situ, probably due to its vasoconstrictor action. However, the actions of ET-1 on PG neurons or its expression in the PG are not known. Using immunohistochemistry, we found that endothelin-like peptides are expressed in the cat PG and CB under normoxic conditions. Exogenous applications of ET-1 increased the chemosensory activity in the vascularly perfused CB but were ineffective on either the CB or PG superfused preparations, both of which are devoid of vascular control. Thus, our data indicate that the excitatory effect of ET-1 in the carotid chemoreceptor system appears to be mainly due to a vasoconstrictor effect in the CB blood vessels.

  8. Functional study of endothelin B receptors in satellite glial cells in trigeminal ganglia.

    PubMed

    Feldman-Goriachnik, Rachel; Hanani, Menachem

    2011-07-13

    There is immunohistochemical evidence for endothelin (ET) receptors in satellite glial cells in sensory ganglia, but there is no information on the function of these receptors. We used calcium imaging to study this question in isolated mouse trigeminal ganglia and found that satellite glial cells are highly sensitive to ET-1, with threshold at 0.05 nM. Responses displayed strong desensitization at ET-1 concentrations of more than 1 nM. A large component of the response persisted when Ca was deleted from the external medium, consistent with Ca release from internal stores. The use of receptor selective agents showed that the responses were mediated by ETB receptors. We conclude that satellite glial cells display endothelin receptors, which may participate in neuron-glia communications in the trigeminal ganglia.

  9. Decreased Endothelin-1 Plasma Levels in Multiple Sclerosis Patients: A Possible Factor of Vascular Dysregulation?

    PubMed Central

    Jankowska-Lech, Irmina; Terelak-Borys, Barbara; Grabska-Liberek, Iwona; Palasik, Witold; Bik, Wojciech; Wolińska-Witort, Ewa

    2015-01-01

    Background Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system with possible involvement of vascular dysregulation secondary to endothelial dysfunction caused by destruction of the vessel wall. Vascular dysregulation leads to excessive vasoconstriction or insufficient vasodilatation, resulting in vasospasm mediated by endothelin-1 (ET-1), the most potent and long-lasting mediator. Vascular dysregulation can play an important role in the pathogenesis of some eye disorders and it has been hypothesized that it is a vascular risk factor for glaucomatous optic neuropathy. The aim of this study was to estimate endothelin-1 (ET-1) plasma levels in patients with MS. Material/Methods The MS group consisted of 39 patients (9 males, 30 females), mean age: 38.8±10.02 years, range: 22–62. The control group consisted of 27 healthy volunteers (3 males and 24 females), mean age: 37.4±10.88 years, range: 20–62; clinically, in a non-active stage of the disease. ET-1 plasma levels were measured using the Endothelin-1 ELISA Kit (Immuno-Biological Laboratories Co., Japan). Statistical analysis was performed with the nonparametric Mann-Whitney U test for independent groups. Results Endothelin-1 (ET-1) plasma levels were significantly lower in MS patients compared to healthy controls: mean value 0.55±0.44 pg/ml (146.05±118.27 fmol/ml) vs. 0.95±0.48 pg/ml (252.83±127.16 fmol/ml); P=0.012. Conclusions Significantly decreased ET-1 plasma levels in the MS patients could reflect the non-active disease at the time of ET-1 measurements or the effects of immunomodulatory treatment, but it cannot be excluded that decreased ET-1 plasma levels in these patients might result from vascular dysregulation. PMID:25864450

  10. Endothelin-1 is elevated in Alzheimer's disease and upregulated by amyloid-β.

    PubMed

    Palmer, Jennifer C; Barker, Rachel; Kehoe, Patrick G; Love, Seth

    2012-01-01

    Vascular dysfunction and lowered cerebral blood flow are thought to contribute to the development and progression of Alzheimer's disease (AD). Endothelin-1 (ET-1) is a potent vasoconstrictor, the production of which is mainly catalyzed by endothelin-converting enzymes (ECEs). We previously showed that ECE-2 is upregulated by amyloid-β (Aβ), and its expression elevated in AD postmortem brain tissue. We have now investigated whether there is a concomitant increase in ET-1. We studied temporal cortex from 20 cases of sporadic AD and 20 matched controls. The cellular distribution of ET-1 was assessed immunohistochemically in paraffin sections. PreproET-1 (EDN1) mRNA and ET-1 protein were measured in homogenates of superior temporal cortex by real-time PCR and sandwich ELISA respectively. Cultured SH-SY5Y human neuroblastoma cells were incubated with 10 μM oligomeric Aβ42 for 24 h, and ET-1 protein level was measured in cell culture supernatants by sandwich ELISA. Antibody to ET-1 labeled neurons throughout the temporal cortex, and the walls of some cerebral blood vessels. ET-1 mRNA measured in the temporal neocortex was significantly elevated in AD when normalized for expression of GAPDH (p = 0.0256) or the neuronal marker neuron-specific enolase (NSE, p = 0.0001). ET-1 protein was also significantly higher in AD than in control tissue, when adjusted for neuronal content by measurement of NSE (p = 0.0275). ET-1 protein in SH-SY5Y cell supernatant rose 1.7-fold after exposure to 10 μM oligomeric Aβ (p = 0.024). These findings provide evidence of overactivity of the endothelin system in AD, further supporting the suggestion that endothelin receptor antagonists may be of value for the treatment of this disease.

  11. Sequence and neuronal expression of mouse endothelin-1 cDNA.

    PubMed

    Kurama, M; Ishida, N; Matsui, M; Saida, K; Mitsui, Y

    1996-07-17

    We have isolated and sequenced a cDNA that encodes mouse endothelin-1 (ET-1). The putative protein contains 202 amino acids corresponds to the prepro-form of ET-1. Twenty-one amino acids sequence of the putative mature ET-1 was identical with that of rat, porcine, bovine, and human. In situ hybridization histochemistry indicate that ET-1 mRNA was expressed in several hypothalamic nuclei including the suprachiasmatic nucleus (SCN) in rodent brain.

  12. Effects of endothelin-1 on prevention of microvascular endothelium injuries in hemorrhagic shock in rats.

    PubMed

    Korzonek-Szlacheta, Ilona; Gwóźdź, Bolesław

    2007-01-01

    The aim of this study was to examine the effects of posthemorrhagic hypovolemia and hypotension upon the microvascular endothelial cells and on activity of antioxidant enzymes in blood, and to investigate the influence of intravenously injected endothelin-1 in rats. The experiment was conducted on 48 rats anesthetized with ethylurethane, subjected to controlled hypotension (under 35-40 mmHg) for 60 min. Endothelin-1 was administered intravenously once at a dose of 50 pmol/kg in the 5th min of hemorrhagic shock. The control group had blood volume restored after 5 min of hypovolemia with hypotension. The arterial blood pressure, systolic and diastolic, and heart rate were monitored. After 60 min, morphological changes in the capillary endothelium of the small intestine were assessed, using electron microscope, and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX) in blood were measured. Animals with hypovolemia and hypotension, had edematous endothelial cells with injured cell-membrane and mitochondria, alongside of the enhancement in SOD activity (p < 0.05) and drop in the activity of CAT and GSH-PX. No signs of vascular endothelium injuries and no reduced enzymatic activities, except for GSH-PX, were observed after restoring the normal blood pressure by means of endothelin-1 in animals with hypovolemia. Hemorrhagic shock caused injuries in intestinal microcascular endothelium. Intravenously administered endothelin-1 quickly restored normal blood pressure, maintained it over a long time, and prevented the consequences of ischemia in microcirculation, thereby prolonging the survival for animals in hemorrhagic shock.

  13. Bosentan, a mixed endothelin receptor antagonist, inhibits superoxide anion-induced pain and inflammation in mice.

    PubMed

    Serafim, Karla G G; Navarro, Suelen A; Zarpelon, Ana C; Pinho-Ribeiro, Felipe A; Fattori, Victor; Cunha, Thiago M; Alves-Filho, Jose C; Cunha, Fernando Q; Casagrande, Rubia; Verri, Waldiceu A

    2015-11-01

    Bosentan is a mixed endothelin receptor antagonist widely used to treat patients with pulmonary arterial hypertension, and the emerging literature suggests bosentan as a potent anti-inflammatory drug. Superoxide anion is produced in large amounts during inflammation, stimulates cytokine production, and thus contributes to inflammation and pain. However, it remains to be determined whether endothelin contributes to the inflammatory response triggered by the superoxide anion. The present study investigated the effects of bosentan in a mouse model of inflammation and pain induced by potassium superoxide, a superoxide anion donor. Male Swiss mice were treated with bosentan (10-100 mg/kg) by oral gavage, 1 h before potassium superoxide injection, and the inflammatory response was evaluated locally and at spinal cord (L4-L6) levels. Bosentan (100 mg/kg) inhibited superoxide anion-induced mechanical and thermal hyperalgesia, overt pain-like behavior (abdominal writhings, paw flinching, and licking), paw edema, myeloperoxidase activity (neutrophil marker) in the paw skin, and leukocyte recruitment in the peritoneal cavity. Bosentan also inhibited superoxide anion-induced interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) production, while it enhanced IL-10 production in the paw skin and spinal cord. Bosentan inhibited the reduction of antioxidant capacity (reduced glutathione, ferric reducing antioxidant power, and ABTS radical scavenging ability) induced by the superoxide anion. Finally, we demonstrated that intraplantar injection of potassium superoxide induces the mRNA expression of prepro-endothelin-1 in the paw skin and spinal cord. In conclusion, our results demonstrated that superoxide anion-induced inflammation, pain, cytokine production, and oxidative stress depend on endothelin; therefore, these responses are amenable to bosentan treatment.

  14. Mutations in the Endothelin Receptor Type A Cause Mandibulofacial Dysostosis with Alopecia

    PubMed Central

    Gordon, Christopher T.; Weaver, K. Nicole; Zechi-Ceide, Roseli Maria; Madsen, Erik C.; Tavares, Andre L.P.; Oufadem, Myriam; Kurihara, Yukiko; Adameyko, Igor; Picard, Arnaud; Breton, Sylvain; Pierrot, Sébastien; Biosse-Duplan, Martin; Voisin, Norine; Masson, Cécile; Bole-Feysot, Christine; Nitschké, Patrick; Delrue, Marie-Ange; Lacombe, Didier; Guion-Almeida, Maria Leine; Moura, Priscila Padilha; Garib, Daniela Gamba; Munnich, Arnold; Ernfors, Patrik; Hufnagel, Robert B.; Hopkin, Robert J.; Kurihara, Hiroki; Saal, Howard M.; Weaver, David D.; Katsanis, Nicholas; Lyonnet, Stanislas; Golzio, Christelle; Clouthier, David E.; Amiel, Jeanne

    2015-01-01

    The endothelin receptor type A (EDNRA) signaling pathway is essential for the establishment of mandibular identity during development of the first pharyngeal arch. We report four unrelated individuals with the syndrome mandibulofacial dysostosis with alopecia (MFDA) who have de novo missense variants in EDNRA. Three of the four individuals have the same substitution, p.Tyr129Phe. Tyr129 is known to determine the selective affinity of EDNRA for endothelin 1 (EDN1), its major physiological ligand, and the p.Tyr129Phe variant increases the affinity of the receptor for EDN3, its non-preferred ligand, by two orders of magnitude. The fourth individual has a somatic mosaic substitution, p.Glu303Lys, and was previously described as having Johnson-McMillin syndrome. The zygomatic arch of individuals with MFDA resembles that of mice in which EDNRA is ectopically activated in the maxillary prominence, resulting in a maxillary to mandibular transformation, suggesting that the p.Tyr129Phe variant causes an EDNRA gain of function in the developing upper jaw. Our in vitro and in vivo assays suggested complex, context-dependent effects of the EDNRA variants on downstream signaling. Our findings highlight the importance of finely tuned regulation of EDNRA signaling during human craniofacial development and suggest that modification of endothelin receptor-ligand specificity was a key step in the evolution of vertebrate jaws. PMID:25772936

  15. Endothelin-converting enzyme-1 (ECE-1) is post-transcriptionally regulated by alternative polyadenylation.

    PubMed

    Whyteside, Alison R; Turner, Anthony J; Lambert, Daniel W

    2014-01-01

    Endothelin-converting enzyme-1 (ECE-1) is the enzyme predominantly responsible for producing active endothelin-1 (ET-1), a mitogenic peptide implicated in the aetiology of a number of diseases, including cancer. Elevated levels of ECE-1 have been observed in a range of malignancies, with high expression conferring poor prognosis and aiding the acquisition of androgen independence in prostate cancer. The mechanisms regulating the expression of ECE-1 in cancer cells are poorly understood, hampering the development of novel therapies targeting the endothelin axis. Here we provide evidence that the expression of ECE-1 is markedly inhibited by its 3'UTR, and that alternative polyadenylation (APA) results in the production of ECE-1 transcripts with truncated 3'UTRs which promote elevated protein expression. Abolition of the ECE-1 APA sites reduced protein expression from a reporter vector in prostate cancer cells, suggesting these sites are functional. This is the first study to identify ECE-1 as a target for APA, a regulatory mechanism aberrantly activated in cancer cells, and provides novel information about the mechanisms leading to ECE-1 overexpression in malignant cells.

  16. Endothelin-1 critically influences cardiac function via superoxide-MMP9 cascade.

    PubMed

    Hathaway, Catherine K; Grant, Ruriko; Hagaman, John R; Hiller, Sylvia; Li, Feng; Xu, Longquan; Chang, Albert S; Madden, Victoria J; Bagnell, C Robert; Rojas, Mauricio; Kim, Hyung-Suk; Wu, Bingruo; Zhou, Bin; Smithies, Oliver; Kakoki, Masao

    2015-04-21

    We have generated low-expressing and high-expressing endothelin-1 genes (L and H) and have bred mice with four levels of expression: L/L, ∼20%; L/+, ∼65%; +/+ (wild type), 100%; and H/+, ∼350%. The hypomorphic L allele can be spatiotemporally switched to the hypermorphic H allele by Cre-loxP recombination. Young adult L/L and L/+ mice have dilated cardiomyopathy, hypertension, and increased plasma volumes, together with increased ventricular superoxide levels, increased matrix metalloproteinase 9 (Mmp9) expression, and reduced ventricular stiffness. H/+ mice have decreased plasma volumes and significantly heavy stiff hearts. Global or cardiomyocyte-specific switching expression from L to H normalized the abnormalities already present in young adult L/L mice. An epithelial sodium channel antagonist normalized plasma volume and blood pressure, but only partially corrected the cardiomyopathy. A superoxide dismutase mimetic made superoxide levels subnormal, reduced Mmp9 overexpression, and substantially improved cardiac function. Genetic absence of Mmp9 also improved cardiac function, but increased superoxide remained. We conclude that endothelin-1 is critical for maintaining normal contractile function, for controlling superoxide and Mmp9 levels, and for ensuring that the myocardium has sufficient collagen to prevent overstretching. Even a modest (∼35%) decrease in endothelin-1 gene (Edn1) expression is sufficient to cause cardiac dysfunction.

  17. Endothelin-1 critically influences cardiac function via superoxide-MMP9 cascade

    PubMed Central

    Hathaway, Catherine K.; Grant, Ruriko; Hagaman, John R.; Hiller, Sylvia; Li, Feng; Xu, Longquan; Chang, Albert S.; Madden, Victoria J.; Bagnell, C. Robert; Rojas, Mauricio; Kim, Hyung-Suk; Wu, Bingruo; Zhou, Bin; Smithies, Oliver; Kakoki, Masao

    2015-01-01

    We have generated low-expressing and high-expressing endothelin-1 genes (L and H) and have bred mice with four levels of expression: L/L, ∼20%; L/+, ∼65%; +/+ (wild type), 100%; and H/+, ∼350%. The hypomorphic L allele can be spatiotemporally switched to the hypermorphic H allele by Cre-loxP recombination. Young adult L/L and L/+ mice have dilated cardiomyopathy, hypertension, and increased plasma volumes, together with increased ventricular superoxide levels, increased matrix metalloproteinase 9 (Mmp9) expression, and reduced ventricular stiffness. H/+ mice have decreased plasma volumes and significantly heavy stiff hearts. Global or cardiomyocyte-specific switching expression from L to H normalized the abnormalities already present in young adult L/L mice. An epithelial sodium channel antagonist normalized plasma volume and blood pressure, but only partially corrected the cardiomyopathy. A superoxide dismutase mimetic made superoxide levels subnormal, reduced Mmp9 overexpression, and substantially improved cardiac function. Genetic absence of Mmp9 also improved cardiac function, but increased superoxide remained. We conclude that endothelin-1 is critical for maintaining normal contractile function, for controlling superoxide and Mmp9 levels, and for ensuring that the myocardium has sufficient collagen to prevent overstretching. Even a modest (∼35%) decrease in endothelin-1 gene (Edn1) expression is sufficient to cause cardiac dysfunction. PMID:25848038

  18. Loss of Function of Endothelin-2 Leads to Reduced Ovulation and CL Formation

    PubMed Central

    Cacioppo, Joseph A.; Oh, Sang Wook; Kim, Hey-young; Cho, Jongki; Lin, Po-Ching Patrick; Yanagisawa, Masashi; Ko, CheMyong

    2014-01-01

    Endothelin-2 (EDN2), a potent vasoconstrictive peptide, is transiently produced by periovulatory follicles at the time of ovulation when corpus luteum (CL) formation begins. EDN2 induces contraction of ovarian smooth muscles ex vivo via an endothelin receptor A-mediated pathway. In this study, we aimed to determine if EDN2 is required for normal ovulation and subsequent CL formation in?vivo. In the ovaries of a mouse model that globally lacks the Edn2 gene (Edn2 knockout mouse; Edn2KO), histology showed that post-pubertal Edn2KO mice possess follicles of all developmental stages, but no corpora lutea. When exogenous gonadotropins were injected to induce super-ovulation, Edn2KO mice exhibited significantly impaired ovulation and CL formation compared to control littermates. Edn2KO ovaries that did ovulate in response to gonadotropins did not contain histologically and functionally identifiable CL. Intra-ovarian injection of EDN2 peptide results suggest partial induction of ovulation in Edn2KO mice. Endothelin receptor antagonism in wild type mice similarly disrupted ovulation, CL formation, and progesterone secretion. Overall, this study suggests that EDN2 is necessary for normal ovulation and CL formation. PMID:24763822

  19. Nitric oxide and endothelin-1 release after one-lung ventilation during thoracoabdominal esophagectomy.

    PubMed

    Lund, M; Ny, L; Malmström, R E; Lundberg, J O; Öst, Å; Björnstedt, M; Lundell, L; Tsai, J A

    2013-01-01

    One-lung ventilation (OLV) is applied during esophagectomy to improve exposure during the thoracic part of the operation. Collapse of lung tissue, shunting of pulmonary blood flow, and changes in alveolar oxygenation during and after OLV may possibly induce an ischemia-reperfusion response in the lung, which may affect the pulmonary endothelium. Such a reaction might thereby contribute to the frequently occurring respiratory complications among these patients. In this small trial, 30 patients were randomized to either OLV (n= 16) or two-lung ventilation (TLV, n= 14) during esophagectomy. Central venous and arterial plasma samples were taken before and after OLV/TLV for analysis of nitrite and a metabolite of nitric oxide (NO), and also during the 1st, 2nd, 3rd, and 10th postoperative day for analysis of endothelin, another endothelium-derived vasoactive mediator. Lung biopsies were taken before and after OLV or TLV, and analyzed regarding immunofluorescence for isoform of NO synthase, a protein upregulated during inflammatory response and also vascular congestion. No changes in lung isoform of NO synthase immunofluorescence or vascular congestion were registered after neither OLV nor TLV. Plasma nitrite and endothelin levels were similar in the two study groups. We conclude that OLV does not seem to have any influence on key regulators of pulmonary vascular tone and inflammation, i.e. NO and endothelin. From this perspective, OLV seems to be a safe method, which defends its clinical position to facilitate surgical exposure during thoracoabdominal esophagectomy.

  20. Genetic blockade of adenosine A2A receptors induces cognitive impairments and anatomical changes related to psychotic symptoms in mice.

    PubMed

    Moscoso-Castro, Maria; Gracia-Rubio, Irene; Ciruela, Francisco; Valverde, Olga

    2016-07-01

    Schizophrenia is a chronic severe mental disorder with a presumed neurodevelopmental origin, and no effective treatment. Schizophrenia is a multifactorial disease with genetic, environmental and neurochemical etiology. The main theories on the pathophysiology of this disorder include alterations in dopaminergic and glutamatergic neurotransmission in limbic and cortical areas of the brain. Early hypotheses also suggested that nucleoside adenosine is a putative affected neurotransmitter system, and clinical evidence suggests that adenosine adjuvants improve treatment outcomes, especially in poorly responsive patients. Hence, it is important to elucidate the role of the neuromodulator adenosine in the pathophysiology of schizophrenia. A2A adenosine receptor (A2AR) subtypes are expressed in brain areas controlling motivational responses and cognition, including striatum, and in lower levels in hippocampus and cerebral cortex. The aim of this study was to characterize A2AR knockout (KO) mice with complete and specific inactivation of A2AR, as an animal model for schizophrenia. We performed behavioral, anatomical and neurochemical studies to assess psychotic-like symptoms in adult male and female KO and wild-type (WT) littermates. Our results show impairments in inhibitory responses and sensory gating in A2AR KO animals. Hyperlocomotion induced by d-amphetamine and MK-801 was reduced in KO animals when compared to WT littermates. Moreover, A2AR KO animals show motor disturbances, social and cognitive alterations. Finally, behavioral impairments were associated with enlargement of brain lateral ventricles and decreased BDNF levels in the hippocampus. These data highlight the role of adenosine in the pathophysiology of schizophrenia and provide new possibilities for the therapeutic management of schizophrenia.

  1. Relaxation of endothelin-1-induced pulmonary arterial constriction by niflumic acid and NPPB: mechanism(s) independent of chloride channel block.

    PubMed

    Kato, K; Evans, A M; Kozlowski, R Z

    1999-03-01

    We investigated the effects of the Cl- channel blockers niflumic acid, 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) and 4, 4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) on endothelin-1 (ET-1)-induced constriction of rat small pulmonary arteries (diameter 100-400 microm) in vitro, following endothelium removal. ET-1 (30 nM) induced a sustained constriction of rat pulmonary arteries in physiological salt solution. Arteries preconstricted with ET-1 were relaxed by niflumic acid (IC50: 35.8 microM) and NPPB (IC50: 21.1 microM) in a reversible and concentration-dependent manner. However, at concentrations known to block Ca++-activated Cl- channels, DIDS (blockade. One possibility is that these compounds may block the Ca++-dependent contractile processes.

  2. Endothelin-1 contributes to endothelial dysfunction and enhanced vasoconstriction through augmented superoxide production in penile arteries from insulin-resistant obese rats: role of ETA and ETB receptors

    PubMed Central

    Sánchez, A; Martínez, P; Muñoz, M; Benedito, S; García-Sacristán, A; Hernández, M; Prieto, D

    2014-01-01

    Background and Purpose We assessed whether endothelin-1 (ET-1) inhibits NO and contributes to endothelial dysfunction in penile arteries in a model of insulin resistance-associated erectile dysfunction (ED). Experimental Approach Vascular function was assessed in penile arteries, from obese (OZR) and lean (LZR) Zucker rats, mounted in microvascular myographs. Changes in basal and stimulated levels of superoxide (O2−) were detected by lucigenin-enhanced chemiluminescence and ET receptor expression was determined by immunohistochemistry. Key Results ET-1 stimulated acute O2− production that was blunted by tempol and the NADPH oxidase inhibitor, apocynin, but markedly enhanced in obese animals. ET-1 inhibited the vasorelaxant effects of ACh and of the NO donor S-nitroso-N-acetyl-DL-penicillamine in arteries from both LZR and OZR. Selective ETA (BQ123) or ETB receptor (BQ788) antagonists reduced both basal and ET-1-stimulated superoxide generation and reversed ET-1-induced inhibition of NO-mediated relaxations in OZR, while only BQ-123 antagonized ET-1 actions in LZR. ET-1-induced vasoconstriction was markedly enhanced by NO synthase blockade and reduced by endothelium removal and apocynin. In endothelium-denuded penile arteries, apocynin blunted augmented ET-1-induced contractions in OZR. Both ETA and ETB receptors were expressed in smooth muscle and the endothelial layer and up-regulated in arteries from OZR. Conclusions and Implications ET-1 stimulates ETA-mediated NADPH oxidase-dependent ROS generation, which inhibits endothelial NO bioavailability and contributes to ET-1-induced contraction in healthy penile arteries. Enhanced vascular expression of ETB receptors contributes to augmented ROS production, endothelial dysfunction and increased vasoconstriction in erectile tissue from insulin-resistant obese rats. Hence, antagonism of ETB receptors might improve the ED associated with insulin-resistant states. PMID:25091502

  3. Endothelin induces two types of contractions of rat uterus: phasic contractions by way of voltage-dependent calcium channels and developing contractions through a second type of calcium channels

    SciTech Connect

    Kozuka, M.; Ito, T.; Hirose, S.; Takahashi, K.; Hagiwara, H.

    1989-02-28

    Effects of endothelin on nonvascular smooth muscle have been examined using rat uterine horns and two modes of endothelin action have been revealed. Endothelin (0.3 nM) caused rhythmic contractions of isolated uterus in the presence of extracellular calcium. The rhythmic contractions were completely inhibited by calcium channel antagonists. These characteristics of endothelin-induced contractions were very similar to those induced by oxytocin. Binding assays using /sup 125/I-endothelin showed that endothelin and the calcium channel blockers did not compete for the binding sites. However, endothelin was unique in that it caused, in addition to rhythmic contractions, a slowly developing monophasic contraction that was insensitive to calcium channel blockers. This developing contraction became dominant at higher concentrations of endothelin and was also calcium dependent.

  4. Enhancement of Adipocyte Browning by Angiotensin II Type 1 Receptor Blockade

    PubMed Central

    Tsukuda, Kana; Mogi, Masaki; Iwanami, Jun; Kanno, Harumi; Nakaoka, Hirotomo; Wang, Xiao-Li; Bai, Hui-Yu; Shan, Bao-Shuai; Kukida, Masayoshi; Higaki, Akinori; Yamauchi, Toshifumi; Min, Li-Juan; Horiuchi, Masatsugu

    2016-01-01

    Browning of white adipose tissue (WAT) has been highlighted as a new possible therapeutic target for obesity, diabetes and lipid metabolic disorders, because WAT browning could increase energy expenditure and reduce adiposity. The new clusters of adipocytes that emerge with WAT browning have been named ‘beige’ or ‘brite’ adipocytes. Recent reports have indicated that the renin-angiotensin system (RAS) plays a role in various aspects of adipose tissue physiology and dysfunction. The biological effects of angiotensin II, a major component of RAS, are mediated by two receptor subtypes, angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R). However, the functional roles of angiotensin II receptor subtypes in WAT browning have not been defined. Therefore, we examined whether deletion of angiotensin II receptor subtypes (AT1aR and AT2R) may affect white-to-beige fat conversion in vivo. AT1a receptor knockout (AT1aKO) mice exhibited increased appearance of multilocular lipid droplets and upregulation of thermogenic gene expression in inguinal white adipose tissue (iWAT) compared to wild-type (WT) mice. AT2 receptor-deleted mice did not show miniaturization of lipid droplets or alteration of thermogenic gene expression levels in iWAT. An in vitro experiment using adipose tissue-derived stem cells showed that deletion of the AT1a receptor resulted in suppression of adipocyte differentiation, with reduction in expression of thermogenic genes. These results indicate that deletion of the AT1a receptor might have some effects on the process of browning of WAT and that blockade of the AT1 receptor could be a therapeutic target for the treatment of metabolic disorders. PMID:27992452

  5. Theory of spin blockade in a triple quantum dots

    NASA Astrophysics Data System (ADS)

    Hsieh, Chang-Yu; Shim, Yun-Pil; Hawrylak, Pawel

    2011-03-01

    We present a theory of electronic properties and spin blockade in a linear triple quantum dots. We use micoroscopic LCHO-CI and double-band Hubbard model to analyze the electronic and spin properties of a triple quantum dots near a symmetrical quadruple point involving the (1,1,1) configuration which is essential for implementing quantum information processing with electron spin. We calculate spectral functions and relate them via the rate equation, including coupling with a phonon bath, to current as a function of applied bias. We show that the spin blockade in a triple quantum dots can serve as a spectroscopic tool to distinguish spin polarized states from spin depolarized states. We also show that a spin blockade is developed only at high bias when an onsite triplet state on the edge quantum dot connected to the source lead becomes accessible in the transport window. In contradiction to the case of double quantum dot molecule, the onsite triplet is not only essential for lifting spin blockade but also important for building up spin polarisation and spin blockade in the system. The authors would like to acknowledge financial support from NSERC, OGS, and QuantumWorks.

  6. Exploring dipole blockade using high- n strontium Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Zhang, Xinyue; Ye, Shuzhen; Dunning, F. Barry; Hiller, Moritz; Yoshida, Shuhei; Burgdörfer, Joachim

    2014-05-01

    Studies of the production of strongly-polarized quasi-1D high- n, n ~ 300 , strontium `` nF'' Rydberg states in an atomic beam by three-photon excitation in a weak dc field suggest that (in the absence of blockade effects) densities of ~106 cm-3 might be achieved. At such densities the interparticle separation, ~ 100 μm , becomes comparable to that at which dipole blockade effects are expected to become important. Apparatus modifications are underway to allow the exploration of blockade at very high- n and the effects of the high energy level density. Blockade is also being examined through calculations of the energy spectrum for two interaction atoms. Access to the blockade regime promises creation of Rydberg atoms at well-defined separations whose interactions can be coherently controlled using electric field pulses thereby enabling study of the dynamics of strongly-coupled Rydberg systems. Research supported by the NSF, the Robert A. Welch Foundation, and the FWF (Austria).

  7. 5-Hydroxytryptamine 1A receptors in the dorsomedial hypothalamus connected to dorsal raphe nucleus inputs modulate defensive behaviours and mediate innate fear-induced antinociception.

    PubMed

    Biagioni, Audrey Franceschi; de Oliveira, Rithiele Cristina; de Oliveira, Ricardo; da Silva, Juliana Almeida; dos Anjos-Garcia, Tayllon; Roncon, Camila Marroni; Corrado, Alexandre Pinto; Zangrossi, Hélio; Coimbra, Norberto Cysne

    2016-03-01

    The dorsal raphe nucleus (DRN) is an important brainstem source of 5-hydroxytryptamine (5-HT), and 5-HT plays a key role in the regulation of panic attacks. The aim of the present study was to determine whether 5-HT1A receptor-containing neurons in the medial hypothalamus (MH) receive neural projections from DRN and to then determine the role of this neural substrate in defensive responses. The neurotracer biotinylated dextran amine (BDA) was iontophoretically microinjected into the DRN, and immunohistochemical approaches were then used to identify 5HT1A receptor-labelled neurons in the MH. Moreover, the effects of pre-treatment of the dorsomedial hypothalamus (DMH) with 8-OH-DPAT and WAY-100635, a 5-HT1A receptor agonist and antagonist, respectively, followed by local microinjections of bicuculline, a GABAA receptor antagonist, were investigated. We found that there are many projections from the DRN to the perifornical lateral hypothalamus (PeFLH) but also to DMH and ventromedial (VMH) nuclei, reaching 5HT1A receptor-labelled perikarya. DMH GABAA receptor blockade elicited defensive responses that were followed by antinociception. DMH treatment with 8-OH-DPAT decreased escape responses, which strongly suggests that the 5-HT1A receptor modulates the defensive responses. However, DMH treatment with WAY-100635 failed to alter bicuculline-induced defensive responses, suggesting that 5-HT exerts a phasic influence on 5-HT1A DMH neurons. The activation of the inhibitory 5-HT1A receptor had no effect on antinociception. However, blockade of the 5-HT1A receptor decreased fear-induced antinociception. The present data suggest that the ascending pathways from the DRN to the DMH modulate panic-like defensive behaviours and mediate antinociceptive phenomenon by recruiting 5-HT1A receptor in the MH.

  8. Landiolol hydrochloride ameliorates acute lung injury in a rat model of early sepsis through the suppression of elevated levels of pulmonary endothelin-1.

    PubMed

    Matsuishi, Yujiro; Jesmin, Subrina; Kawano, Satoru; Hideaki, Sakuramoto; Shimojo, Nobutake; Mowa, Chishimba Nathan; Akhtar, Shila; Zaedi, Sohel; Khatun, Tanzila; Tsunoda, Yoshiya; Kiwamoto, Takumi; Hizawa, Nobuyuki; Inoue, Yoshiaki; Mizutani, Taro

    2016-12-01

    Among the dysfunctions and pathologies associated with sepsis, the underlying molecular mechanisms of sepsis-induced acute lung injury (ALI) are poorly understood. Endothelin (ET)-1, a potent vasoconstrictor and pro-inflammatory peptide, is known to be involved in the pathogenesis of ALI in a rat model of sepsis. Here, we investigated whether landiolol hydrochloride, an ultra-short-acting β-blocker, plays a crucial role in ameliorating and attenuating LPS-induced ALI through modulation of the ET-1 system. Male Wistar rats at 8weeks of age were administered with either saline or lipopolysaccharide (LPS) for three hours (3h) and some of the LPS-administered rats were continuously treated with landiolol for 3h. ALI was induced by LPS, including levels of both circulatory and pulmonary TNF-α and IL-6 but [PaO2] was significantly decreased. LPS also induced a significant increase in levels of pulmonary ET-1 and ET-A receptor, but levels of ET-B receptor, which has vasodilating effects, were remarkably diminished. Further, LPS administration upregulated the pulmonary expression of HIF-1α. Finally, the treatment of LPS-administered rats with landiolol for 3h ameliorated and prevented ALI, normalized the altered levels of pulmonary ET-1 and ET-A receptors. Landiolol also induced significant down-regulation of ET-B receptor in lung tissues in the early hours (phase) of sepsis. However, Landiolol treatment had no effect on the up-regulated inflammatory mediators (TNF-α, IL-6) in both plasma and lung tissues during sepsis, and expression of pulmonary HIF-1α also remained unchanged after landiolol treatment. Collectively, these data led us to conclude that landiolol may ameliorate sepsis-induced ALI via the pulmonary ET system.

  9. Decreased endothelin receptor B expression in large primary uveal melanomas is associated with early clinical metastasis and short survival

    PubMed Central

    Smith, S L; Damato, B E; Scholes, A G M; Nunn, J; Field, J K; Heighway, J

    2002-01-01

    The most devastating aspect of cancer is the metastasis of tumour cells to organs distant from the original tumour site. The major problem facing oncologists treating uveal melanoma, the most common cancer of the eye, is metastatic disease. To lower mortality, it is necessary to increase our understanding of the molecular genetic alterations involved in this process. Using suppression subtractive hybridisation, we have analysed differential gene expression between four primary tumours from patients who have developed clinical metastasis and four primary tumours from patients with no evidence of metastasis to date. We have identified endothelin receptor type B as differentially expressed between these tumours and confirmed this observation using comparative multiplex RT–PCR. In a further 33 tumours, reduced endothelin receptor type B expression correlated with death from metastatic disease. Reduced expression also correlated with other known prognostic indicators, including the presence of epithelioid cells, chromosome 3 allelic imbalance and chromosome 8q allelic imbalance. Endothelin receptor type B expression was also reduced in four out of four primary small cell lung carcinomas compared to normal bronchial epithelium. We also show that the observed down-regulation of endothelin receptor type B in uveal melanoma was not due to gene deletion. Our findings suggest a role for endothelin receptor type B in the metastasis of uveal melanoma and, potentially, in the metastasis of other neural crest tumours. British Journal of Cancer (2002) 87, 1308–1313. doi:10.1038/sj.bjc.6600620 www.bjcancer.com © 2002 Cancer Research UK PMID:12439722

  10. Dexamethasone added to lidocaine prolongs axillary brachial plexus blockade.

    PubMed

    Movafegh, Ali; Razazian, Mehran; Hajimaohamadi, Fatemeh; Meysamie, Alipasha

    2006-01-01

    Different additives have been used to prolong regional blockade. We designed a prospective, randomized, double-blind study to evaluate the effect of dexamethasone added to lidocaine on the onset and duration of axillary brachial plexus block. Sixty patients scheduled for elective hand and forearm surgery under axillary brachial plexus block were randomly allocated to receive either 34 mL lidocaine 1.5% with 2 mL of isotonic saline chloride (control group, n = 30) or 34 mL lidocaine 1.5% with 2 mL of dexamethasone (8 mg) (dexamethasone group, n = 30). Neither epinephrine nor bicarbonate was added to the treatment mixture. We used a nerve stimulator and multiple stimulations technique in all of the patients. After performance of the block, sensory and motor blockade of radial, median, musculocutaneous, and ulnar nerves were recorded at 5, 15, and 30 min. The onset time of the sensory and motor blockade was defined as the time between last injection and the total abolition of the pinprick response and complete paralysis. The duration of sensory and motor blocks were considered as the time interval between the administration of the local anesthetic and the first postoperative pain and complete recovery of motor functions. Sixteen patients were excluded because of unsuccessful blockade. The duration of surgery and the onset times of sensory and motor block were similar in the two groups. The duration of sensory (242 +/- 76 versus 98 +/- 33 min) and motor (310 +/- 81 versus 130 +/- 31 min) blockade were significantly longer in the dexamethasone than in the control group (P < 0.01). We conclude that the addition of dexamethasone to lidocaine 1.5% solution in axillary brachial plexus block prolongs the duration of sensory and motor blockade.

  11. Carbenoxolone blockade of neuronal network activity in culture is not mediated by an action on gap junctions

    PubMed Central

    Rouach, N; Segal, M; Koulakoff, A; Giaume, C; Avignone, E

    2003-01-01

    Spontaneous activity in the central nervous system is strongly suppressed by blockers of gap junctions (GJs), suggesting that GJs contribute to network activity. However, the lack of selective GJ blockers prohibits the determination of their site of action, i.e. neuronal versus glial. Astrocytes are strongly coupled through GJs and have recently been shown to modulate synaptic transmission, yet their role in neuronal network activity was not analysed. The present study investigated the effects and site of action of the GJ blocker, carbenoxolone (CBX), on neuronal network activity. To this end, we used cultures of hippocampal or cortical neurons, plated on astrocytes. In these cultures neurons display spontaneous synchronous activity and GJs are found only in astrocytes. CBX induced in these neurons a reversible suppression of spontaneous action potential discharges, synaptic currents and synchronised calcium oscillations. Moreover, CBX inhibited oscillatory activity induced by the GABAA antagonist, bicuculline. These effects were not due to blockade of astrocytic GJs, since they were not mimicked nor occluded by endothelin-1 (ET-1), a peptide known to block astrocytic GJs. Also, these effects were still present in co-cultures of wild-type neurons plated on astrocytes originating from connexin-43 (Cx43) knockout mice, and in neuronal cultures which contain few isolated astrocytes. CBX was not likely to exert its effect through neuronal GJs either, as immunostaining for major neuronal connexins (Cx) as well as dye or electrical coupling, were not detected in the different models of cultured neurons examined. Finally while CBX (at 100 μm) did not modify presynaptic transmitter release and postsynaptic responses to glutamate, it did cause an increase in the action potential threshold and strongly decreased the firing rate in response to a sustained depolarising current. These data demonstrate that CBX does not exert its action on network activity of cultured neurons

  12. Changes of endothelin-1 and big endothelin-1 levels and action potential duration during myocardial ischemia-reperfusion in dogs with and without ventricular fibrillation.

    PubMed

    Vágó, Hajnalka; Soós, Pál; Zima, Endre; Gellér, László; Keltai, Katalin; Róka, Attila; Kékesi, Violetta; Juhász-Nagy, Alexander; Merkely, Béla

    2004-11-01

    Myocardial ischemia-reperfusion is associated with increased production of endothelin-1 (ET-1). Moreover, exogenous ET-1 has arrhythmogenic properties. Our aim was to investigate the correlation between endogenous ET-1, big ET-1 levels and epicardial monophasic action potential duration during myocardial ischemia-reperfusion in anesthetized dogs. Thirty-minute myocardial ischemia was followed by a 90-minute reperfusion period in 18 mongrel dogs. The total incidence of ventricular fibrillation (VF) during ischemia and reperfusion was 11.1% and 33.3%, respectively. During ischemia, the monophasic action potential duration at 90% repolarization (MAPD90) decreased significantly (control versus ischemia, 30 minutes, 224.7 +/- 7.1 ms versus 173.8 +/- 7.6 ms; P < 0.05), while during reperfusion a significant prolongation of MAPD90 was observed (ischemia, 30 minutes versus reperfusion, 30 minutes, 173.8 +/- 7.6 ms versus 249.7 +/- 9.9 ms, P < 0.05). During reperfusion ET-1 and big ET-1 levels increased significantly in the coronary sinus and femoral artery (control versus reperfusion, 90 minutes: coronary sinus ET-1, 15.1 +/- 1.4 fmol/mL versus 22.3 +/- 1.1 fmol/mL; big ET-1, 14.7 +/- 1.9 fmol/mL versus 27.4 +/- 2.3 fmol/mL; P < 0.05). The ET-1 concentration increased to a higher level during ischemia in dogs with VF compared with dogs surviving ischemia-reperfusion (non-VF versus VF: control, 15.1 +/- 1.3 versus 15.2 +/- 1.3; ischemia, 30 minutes, 17.6 +/- 1.2 fmol/mL versus 22 +/- 1.6 fmol/mL; P < 0.05), demonstrating a trend of correlation between endothelin levels and development of VF (P = 0.07). ET-1 and big ET-1 levels increased during reperfusion and in the VF group during ischemia; however, there was no correlation between endothelin levels and MAPD90.

  13. Endothelin-1 inhibits TNF alpha-induced iNOS expression in 3T3-F442A adipocytes.

    PubMed

    Mérial-Kieny, Christelle; Lonchampt, Michel; Cogé, Francis; Verwaerde, Patrick; Galizzi, Jean-Pierre; Boutin, Jean A; Lafontan, Max; Levens, Nigel; Galitzky, Jean; Félétou, Michel

    2003-07-01

    1. Endothelin-1 (ET-1) and tumor necrosis factor alpha (TNFalpha) by their action on adipocytes have been independently linked to the pathogenesis of insulino-resistance. In isolated adipocytes, TNFalpha induces the expression of the inducible nitric oxide synthase (iNOS). The purpose of the present work was, in the 3T3-F442A adipocyte cell line, to characterise TNFalpha-induced iNOS expression and to determine whether or not ET-1 could influence TNFalpha-induced iNOS expression and NO production. 2. In differentiated 3T3-F442A, treatment with TNFalpha (20 ng ml(-1)) induced the expression of a functional iNOS as demonstrated by nitrite assay, Western blot, reverse transcription-polymerase chain reaction and Northern blot analysis. TNFalpha-induced iNOS expression requires nuclear factor kappaB activation, but does not necessitate the activation of the PI-3 kinase/Akt and P38-MAP kinase pathways. 3. ET-1, but not ET-3, inhibited the TNFalpha-induced expression of iNOS protein and mRNA as well as nitrite production. The effects of ET-1 were blocked by a specific ETA (BQ123, pA(2) 7.4) but not by a specific ETB receptor antagonist (BQ788). 3T3-F442A adipocytes express the mRNAs for prepro-ET-1 and the ET-A receptor subtype, but not for the ET-B subtype. 4. The inhibitory effect of ET-1 was not affected by bisindolylmaleimide, SB 203580 or indomethacin, inhibitors of protein kinase C, p38-MAP kinase and cyclooxygenase, respectively, and was not associated with cAMP production. However, the effect of ET-1 was partially reversed by wortmannin, suggesting the involvement of PI3 kinase in the transduction signal of ET-1. 5. Differentiated 3T3-F442A adipocytes did not release ET-1 with or without exposure to TNFalpha, although the mRNA for preproET-1 was detected in both pre- and differentiated adipocytes. 6. Thus, these results confirm that adipocytes are a target for circulating ET-1 and demonstrate that the activation of the ETA receptor subtype can prevent TNFalpha

  14. Effect of YM218, a nonpeptide vasopressin V(1A) receptor-selective antagonist, on rat mesangial cell hyperplasia and hypertrophy.

    PubMed

    Tahara, Atsuo; Tsukada, Junko; Tomura, Yuichi; Suzuki, Takeshi; Yatsu, Takeyuki; Shibasaki, Masayuki

    2007-06-01

    Mesangial cell growth constitutes a key feature of progressive glomerular injury. Vasopressin (AVP), a potent peptide vasoconstrictor, acts on mesangial cells through the V(1A) receptors, inducing contraction and cell proliferation. This study examined the effects of YM218, a nonpeptide AVP V(1A) receptor-selective antagonist, on the mitogenic and hypertrophic effects of AVP in rat mesangial cells. When added to mesangial cells whose growth was arrested, AVP concentration-dependently induced hyperplasia and hypertrophy. YM218 potently prevented AVP-induced hyperplasia and hypertrophy of these cells. Furthermore, AVP stimulated endothelin (ET)-1 secretion from mesangial cells in a concentration-dependent manner and this effect was potently inhibited by YM218. ET-1 also induced hyperplasia and hypertrophy in mesangial cells and this effect was completely abolished by ET(A) receptor-selective antagonist YM598. In addition, AVP-induced hyperplasia and hypertrophy were partly inhibited by YM598. These results suggest that AVP may modulate mesangial cell growth not only by its direct action but also through the stimulation of ET-1 secretion. YM218 displays high potency in inhibiting the AVP-induced physiologic responses of mesangial cells via the V(1A) receptors and is a potent pharmacologic probe for investigating the physiologic and pathophysiologic roles of AVP in several renal diseases.

  15. Role of 5-HT5A receptors in the consolidation of memory.

    PubMed

    Gonzalez, Roberto; Chávez-Pascacio, Karla; Meneses, Alfredo

    2013-09-01

    5-HT5 receptor occurs in brain areas implicated in learning and memory. Hence, the effects (0.01-3.0 mg/kg) of SB-6995516 (a 5-HT5A receptor antagonist) in the associative learning task of autoshaping were studied. The results showed that post-training injection of SB-699551 decreased conditioned responses (CR) during short-term (STM; 1.5h; at 0.1mg/kg) and long-term memory (LTM; 24 h; at 3.0 mg/kg) relative to the vehicle animals. Moreover, considering that there are no selective 5-HT5A receptor agonists, next, diverse doses of the serotonin precursor l-tryptophan were studied during STM and LTM, showing that l-tryptophan (5-100mg/kg) facilitated performance, particularly at 50mg/kg. In interactions experiments, l-tryptophan (50 mg/kg) attenuated the impairment effect induced by SB-699551 (either 0.3 or 3.0 mg/kg). All together this evidence suggests that the blockade of 5-HT5A receptor appear to be able to impair STM and LTM (24 h), while its stimulation might facilitate it. Of course further investigation is necessary, meanly with selective 5-HT5A compounds are necessary.

  16. Effects of the mammalian vasoconstrictor peptide, endothelin-1, on Tetrahymena pyriformis GL, and the immunocytological detection of endogenous endothelin-like activity.

    PubMed

    Köhidai, L; Csaba, G

    1995-06-01

    The vasoconstrictor endothelin-1 (ET-1) is shown to have significant physiological effects on a unicellular organism, Tetrahymena pyriformis. These responses include: (1) A significant increase in intracellular [Ca2+] induced by 10(-10) M ET-1; (2) Increased chemotaxis, maximal at 10(-10) M; and (3) A small inhibition of proliferation at the 10(-13)-10(-12) M concentration range. Immunocytochemical detection of endogenous ET-1 using rabbit antibodies directed against human or porcine ET-1 indicates that this is a further example of the widening group of vertebrate hormones now known to be synthesized by Tetrahymena. These observations suggest that hormones are of considerable antiquity in their phylogenetic appearance and have been highly conserved throughout evolution.

  17. Safety guideline: skin antisepsis for central neuraxial blockade.

    PubMed

    Obstetric Anaesthetists' Association; Campbell, J P; Plaat, F; Checketts, M R; Bogod, D; Tighe, S; Moriarty, A; Koerner, R

    2014-11-01

    Concise guidelines are presented that recommend the method of choice for skin antisepsis before central neuraxial blockade. The Working Party specifically considered the concentration of antiseptic agent to use and its method of application. The advice presented is based on previously published guidelines, laboratory and clinical studies, case reports, and on the known properties of antiseptic agents.

  18. Peripheral metabolic effects of endocannabinoids and cannabinoid receptor blockade.

    PubMed

    Engeli, Stefan

    2008-01-01

    The endocannabinoid system consists of endogenous arachidonic acid derivates that activate cannabinoid receptors. The two most prominent endocannabinoids are anandamide and 2-arachidonoyl glycerol. In obesity, increased concentrations of circulating and tissue endocannabinoid levels have been described, suggesting increased activity of the endocannabinoid system. Increased availability of endocannabinoids in obesity may over-stimulate cannabinoid receptors. Blockade of cannabinoid type 1 (CB1) receptors was the only successful clinical development of an anti-obesity drug during the last decade. Whereas blockade of CB1 receptors acutely reduces food intake, the long-term effects on metabolic regulation are more likely mediated by peripheral actions in liver, skeletal muscle, adipose tissue, and the pancreas. Lipogenic effects of CB1 receptor signalling in liver and adipose tissue may contribute to regional adipose tissue expansion and insulin resistance in the fatty liver. The association of circulating 2-arachidonoyl glycerol levels with decreased insulin sensitivity strongly suggests further exploration of the role of endocannabinoid signalling for insulin sensitivity in skeletal muscle, liver, and adipose tissue. A few studies have suggested a specific role for the regulation of adiponectin secretion from adipocytes by endocannabinoids, but that has to be confirmed by more experiments. Also, the potential role of CB1 receptor blockade for the stimulation of energy expenditure needs to be studied in the future. Despite the current discussion of safety issues of cannabinoid receptor blockade, these findings open a new and exciting perspective on endocannabinoids as regulators of body weight and metabolism.

  19. Merchant Shipping in a Chinese Blockade of Taiwan

    DTIC Science & Technology

    2007-01-01

    8:14:41 AM Color profile: Disabled Composite Default screen privateers, and blockade runners risking death in conflicts to which they had no...particular vessel at any given time, then, can be a challenging endeavor in- volving a maze of corporate relationships and contractual legalese. But more

  20. A new regime of Pauli-spin blockade

    NASA Astrophysics Data System (ADS)

    Perron, Justin K.; Stewart, M. D.; Zimmerman, Neil M.

    2016-04-01

    Pauli-spin blockade (PSB) is a transport phenomenon in double quantum dots that allows for a type of spin to charge conversion often used to probe fundamental physics such as spin relaxation and singlet-triplet coupling. In this paper, we theoretically explore Pauli-spin blockade as a function of magnetic field B applied parallel to the substrate. In the well-studied low magnetic field regime, where PSB occurs in the forward (1, 1) → (0, 2) tunneling direction, we highlight some aspects of PSB that are not discussed in detail in existing literature, including the change in size of both bias triangles measured in the forward and reverse biasing directions as a function of B. At higher fields, we predict a crossover to "reverse PSB" in which current is blockaded in the reverse direction due to the occupation of a spin singlet as opposed to the traditional triplet blockade that occurs at low fields. The onset of reverse PSB coincides with the development of a tail like feature in the measured bias triangles and occurs when the Zeeman energy of the polarized triplet equals the exchange energy in the (0, 2) charge configuration. In Si quantum dots, these fields are experimentally accessible; thus, this work suggests a way to observe a crossover in magnetic field to qualitatively different behavior.

  1. Accurate Coulomb blockade thermometry up to 60 kelvin.

    PubMed

    Meschke, M; Kemppinen, A; Pekola, J P

    2016-03-28

    We demonstrate experimentally a precise realization of Coulomb blockade thermometry working at temperatures up to 60 K. Advances in nano-fabrication methods using electron beam lithography allow us to fabricate uniform arrays of sufficiently small tunnel junctions to guarantee an overall temperature reading precision of about 1%.

  2. CTLA-4 Blockade-Based Immunotherapy in Prostate Cancer

    DTIC Science & Technology

    2006-01-01

    V, Bok R, Small EJ. Prostate-specific antigen kinetics as a measure of the biologic effect of granulocyte- macrophage colony-stimulating factor in...Kwon ED, Truong T, Choi EM, Greenberg NM, et al. Combination immunotherapy of primary prostate cancer in a transgenic mouse model using CTLA-4 blockade

  3. Human breast cancer cells contain a phosphoramidon-sensitive metalloproteinase which can process exogenous big endothelin-1 to endothelin-1: a proposed mitogen for human breast fibroblasts.

    PubMed Central

    Patel, K. V.; Schrey, M. P.

    1995-01-01

    Endothelin-1 (ET-1) levels are elevated in human breast tumours compared with normal and benign tissues, and in the presence of insulin-like growth factor 1 (IGF-I) ET-1 is a potent mitogen for human breast fibroblasts. In this study we have examined the ability of intact human breast cancer cell lines to process exogenously added big ET-1 (1-38) to the active mature ET-1 peptide by using a specific radioimmunometric assay. In both hormome-dependent (MCF-7, T47-D) and hormone-independent (MDA-MB-231) breast cancer cell lines the putative endothelin-converting enzyme (ECE) exhibited apparent Michaelis-Menten kinetics when converting added big ET-1 to ET-1. Both basal ET-1 production and exogenously added big ET-1 to ET-1 conversion were greatly reduced in all three cell lines in response to the metalloproteinase inhibitor phosphoramidon but were insensitive to other classes of protease inhibitors. Inhibition was also observed when cells were incubated in the presence of the divalent cation chelators 1,10-phenanthroline and EDTA. In MCF-7 cells the optimal pH for the ECE activity using a saponin cell permeabilisation procedure was found to residue within a narrow range of 6.2-7.26. Our results indicate that human breast cancer cells contain a neutral phosphoramidon-sensitive metalloproteinase which can process big ET-1 to ET-1. In the breast this conversion could contribute substantially to the local extracellular levels of this proposed paracrine breast fibroblast mitogen. PMID:7880721

  4. Mesangial cell, glomerular and renal vascular responses to endothelin in the rat kidney. Elucidation of signal transduction pathways.

    PubMed Central

    Badr, K F; Murray, J J; Breyer, M D; Takahashi, K; Inagami, T; Harris, R C

    1989-01-01

    We investigated the actions of endothelin in anesthetized rats and cultured mesangial cells. Intravenous infusion of endothelin (10 pmol/min) decreased renal blood flow by 44% at 20 min without changing arterial pressure, which subsequently rose significantly from 124 +/- 3 to 133 +/- 4 mmHg over 60 min. Micropuncture during the nonhypertensive period revealed increases in afferent (65%) and efferent (82%) arteriolar resistances, thereby reducing nephron plasma flow rate. The glomerular ultrafiltration coefficient (Kf) fell from 0.097 +/- 0.035 to 0.031 +/- 0.011 nl/(s.mmHg) as did single nephron filtration rate (41 +/- 3 to 19 +/- 3 nl/min). Addition of 5 nM endothelin to mesangial cells plated on a silicone rubber substrate increased the intensity and number of tension-generated wrinkles, and caused their reappearance in forskolin prerelaxed cells. 20-30 s following exposure of fura-2 loaded mesangial cells to 10 nM endothelin, single cell intracellular calcium concentration ([Ca]i) increased from a mean baseline value of 66 +/- 11 (SE) to a peak of 684 +/- 250 nM (P less than 0.05) followed by a sustained elevation at 145 +/- 42 nM. Anion exchange HPLC revealed rapid (15 s) and dose-dependent stimulation of inositol 1,4,5-trisphosphate (IP3) generation following exposure of [3H]myoinositol preloaded mesangial cells to 10-100 nM endothelin. Endothelin also led to intracellular alkalinization of 2'7'-bis(2-carboxy-ethyl)-5(and-6)carboxyfluorescein (BCECF)-loaded mesangial cells and its addition was associated with dramatic augmentation of mitogenic activity. Thus, endothelin exerts potent constrictor effects on renal arterioles which precede its systemic hypertensive action. It lowers Kf and contracts mesangial cells, likely through stimulation of IP3 generation and elevation of [Ca]i. It is a potent mesangial cell mitogen. These studies define functional responses and signal transduction pathways for endothelin in the rat kidney and propose a potential role for

  5. Chemical function based pharmacophore generation of endothelin-A selective receptor antagonists.

    PubMed

    Funk, Oliver F; Kettmann, Viktor; Drimal, Jan; Langer, Thierry

    2004-05-20

    Both quantitative and qualitative chemical function based pharmacophore models of endothelin-A (ET(A)) selective receptor antagonists were generated by using the two algorithms HypoGen and HipHop, respectively, which are implemented in the Catalyst molecular modeling software. The input for HypoGen is a training set of 18 ET(A) antagonists exhibiting IC(50) values ranging between 0.19 nM and 67 microM. The best output hypothesis consists of five features: two hydrophobic (HY), one ring aromatic (RA), one hydrogen bond acceptor (HBA), and one negative ionizable (NI) function. The highest scoring Hip Hop model consists of six features: three hydrophobic (HY), one ring aromatic (RA), one hydrogen bond acceptor (HBA), and one negative ionizable (NI). It is the result of an input of three highly active, selective, and structurally diverse ET(A) antagonists. The predictive power of the quantitative model could be approved by using a test set of 30 compounds, whose activity values spread over 6 orders of magnitude. The two pharmacophores were tested according to their ability to extract known endothelin antagonists from the 3D molecular structure database of Derwent's World Drug Index. Thereby the main part of selective ET(A) antagonistic entries was detected by the two hypotheses. Furthermore, the pharmacophores were used to screen the Maybridge database. Six compounds were chosen from the output hit lists for in vitro testing of their ability to displace endothelin-1 from its receptor. Two of these are new potential lead compounds because they are structurally novel and exhibit satisfactory activity in the binding assay.

  6. Applicability of green fluorescence protein in the study of endothelin converting enzyme-1c trafficking.

    PubMed

    Kuruppu, Sanjaya; Tochon-Danguy, Nathalie; Smith, A Ian

    2013-03-01

    Endothelin-1 (ET-1) is one of the most potent peptide vasoconstrictors known. It is produced upon the cleavage of its precursor big endothelin-1 by endothelin converting enzyme-1 (ECE-1). Production of ET-1 is thought to be dependent upon the expression of ECE-1 at the cell surface. Therefore, mechanisms inducing the trafficking of ECE-1 to the cell surface have been the focus of recent research. This research has identified phosphorylation of the cytoplasmic region of ECE-1 as a main cellular signal inducing its trafficking to the cell surface. Previous studies have used green fluorescent protein (GFP) tagged ECE-1 to monitor phosphorylation induced trafficking of ECE-1 to the cell surface. However, it has been speculated that the addition of the GFP tag can itself alter enzyme activity and phosphorylation of ECE-1, and hence the suitability of GFP or any other protein tag in studying ECE-1 distribution and trafficking. ECE-1c is the most widely expressed isoform in endothelial cells. We therefore expressed ECE-1c with a GFP tag either at the N or C-terminus of ECE-1c. Catalytic activity and effect on protein kinase C (PKC) induced phosphorylation was compared between the two chimeras and wild-type ECE-1c. Our results indicate that positioning of the GFP tag on the C-terminus abrogates activity without effecting PKC-induced phosphorylation. However, GFP tag on the N-terminus has the opposite effect. Results of this study shed light on the applicability of GFP or perhaps other protein tags in studying ECE-1c distribution and trafficking.

  7. Endothelin-converting enzymes degrade α-synuclein and are reduced in dementia with Lewy bodies.

    PubMed

    Miners, J Scott; Love, Seth

    2017-02-07

    We have examined the roles of the endothelin-converting enzyme-1 and -2 (ECE-1 and ECE-2) in the homeostasis of α-synuclein (α-syn) and pathogenesis of Lewy body disease. The ECEs are named for their ability to convert inactive big endothelin to the vasoactive peptide endothelin-1 (EDN1). We have found that ECE-1 and ECE-2 cleave and degrade α-syn in vitro and siRNA-mediated knockdown of ECE-1 and ECE-2 in SH-SY5Y neuroblastoma cells significantly increased α-syn both intracellularly (within the cell lysate) (P < 0.05 for both ECE-1 and -2) and extracellularly (in the surrounding medium) (P < 0.05 for ECE-1 and P = 0.07 for ECE-2). Double immunofluorescent labelling showed co-localisation of ECE-1 and ECE-2 with α-syn within the endolysosomal system (confirmed by a proximity ligation assay). To assess the possible relevance of these findings to human Lewy body disease, we measured ECE-1 and ECE-2 levels by sandwich ELISA in post-mortem samples of cingulate cortex (a region with a predilection for Lewy body pathology) in dementia with Lewy bodies (DLB) and age-matched controls. ECE-1 (P < 0.001) and ECE-2 (P < 0.01) levels were significantly reduced in DLB and both enzymes correlated inversely with the severity of Lewy body pathology as indicated by the level of α-syn phosphorylated at Ser129 (r = -0.54, P < 0.01 for ECE-1 and r = -0.49, P < 0.05 for ECE-2). Our novel findings suggest a role for ECEs in the metabolism of α-syn that could contribute to the development and progression of DLB. This article is protected by copyright. All rights reserved.

  8. Alteration of Endothelins: A Common Pathogenetic Mechanism in Chronic Diabetic Complications

    PubMed Central

    Khan, Zia Ali; Cukiernik, Mark; Fukuda, Gen; Chen, Shali; Mukherjee, Suranjana

    2002-01-01

    Endothelin (ET) peptides perform several physiological, vascular, and nonvascular functions and are widely distributed in a number of tissues. They are altered in several disease processes including diabetes. Alteration of ETs have been demonstrated in organs of chronic diabetic complications in both experimental and clinical studies. The majority of the effects of ET alteration in diabetes are due to altered vascular function. Furthermore, ET antagonists have been shown to prevent structural and functional changes induced by diabetes in animal models. This review discusses the contribution of ETs in the pathogenesis and the potential role of ET antagonism in the treatment of chronic diabetic complications. PMID:12546275

  9. Endothelin-3 production by human rhabdomyosarcoma: a possible new marker with a paracrine role.

    PubMed

    Palladini, Arianna; Astolfi, Annalisa; Croci, Stefania; De Giovanni, Carla; Nicoletti, Giordano; Rosolen, Angelo; Sartori, Francesca; Lollini, Pier-Luigi; Landuzzi, Lorena; Nanni, Patrizia

    2006-03-01

    Several autocrine and paracrine growth factor circuits have been found in human rhabdomyosarcoma cells. In this study we show that endothelin-3 (ET-3), a vasoactive peptide, is produced by human rhabdomyosarcoma cell lines, whereas it is not expressed by human sarcoma cell lines of non-muscle origin. We did not find evidence of a significant autocrine loop; nevertheless ET-3 produced by rhabdomyosarcoma cells can act as a paracrine factor, since it promotes migration of endothelial cells. Moreover ET-3 is present in plasma of mice bearing xenografts of human rhabdomyosarcoma cells, and may be potential new marker of the human rhabdomyosarcoma to be studied further.

  10. An emerging role for microRNA in the regulation of endothelin-1

    PubMed Central

    Jacobs, Mollie E.; Wingo, Charles S.; Cain, Brian D.

    2013-01-01

    Endothelin-1 (ET-1) is a peptide signaling molecule serving diverse functions in many different tissues such as the vasculature and the kidney. The primary mechanism thought to control ET-1 bioavailability is the rate of transcription from the ET-1 gene (EDN1), but recent research suggests that EDN1 expression is attenuated by microRNA (miRNA)—mediated regulation. The action of specific miRNAs on EDN1 mRNA appears to vary greatly in a tissue specific manner. This review provides a summary of our current understanding of miRNA-EDN1 interaction. PMID:23424003

  11. Partial neuromuscular blockade in humans enhances muscle blood flow during exercise independently of muscle oxygen uptake and acetylcholine receptor blockade.

    PubMed

    Hellsten, Ylva; Krustrup, Peter; Iaia, F Marcello; Secher, Niels H; Bangsbo, Jens

    2009-04-01

    This study examined the role of acetylcholine for skeletal muscle blood flow during exercise by use of the competitive neuromuscular blocking agent cisatracurium in combination with the acetylcholine receptor blocker glycopyrrone. Nine healthy male subjects performed a 10-min bout of one-legged knee-extensor exercise (18 W) during control conditions and with cisatracurium blockade, as well as with cisatracurium blockade with prior glycopyrrone infusion. Thigh blood flow and vascular conductance in control and with cisatracurium infusion were similar at rest and during passive movement of the leg, but higher (P < 0.05) during exercise with cisatracurium than in control (3.83 +/- 0.42 vs. 2.78 +/- 0.21 l/min and 26.9 +/- 3.4 vs. 21.8 +/- 2.0 ml.min(-1).mmHg(-1) at the end of exercise). Thigh oxygen uptake was similar in control and with cisatracurium infusion both at rest and during exercise, being 354 +/- 33 and 406 +/- 34 ml/min, at the end of exercise. Combined infusion of cisatracurium and glycopyrrone caused a similar increase in blood flow as cisatracurium infusion alone. The current results demonstrate that neuromuscular blockade leads to enhanced thigh blood flow and vascular conductance during exercise, events that are not associated with either acetylcholine or an increased oxygen demand. The results do not support an essential role for acetylcholine, released form the neuromuscular junction, in exercise hyperemia or for the enhanced blood flow during neuromuscular blockade. The enhanced exercise hyperemia during partial neuromuscular blockade may be related to a greater recruitment of fast-twitch muscle fibers.

  12. Adenosine A2A Receptors and A2A Receptor Heteromers as Key Players in Striatal Function

    PubMed Central

    Ferré, Sergi; Quiroz, César; Orru, Marco; Guitart, Xavier; Navarro, Gemma; Cortés, Antonio; Casadó, Vicent; Canela, Enric I.; Lluis, Carme; Franco, Rafael

    2011-01-01

    A very significant density of adenosine A2A receptors (A2ARs) is present in the striatum, where they are preferentially localized postsynaptically in striatopallidal medium spiny neurons (MSNs). In this localization A2ARs establish reciprocal antagonistic interactions with dopamine D2 receptors (D2Rs). In one type of interaction, A2AR and D2R are forming heteromers and, by means of an allosteric interaction, A2AR counteracts D2R-mediated inhibitory modulation of the effects of NMDA receptor stimulation in the striatopallidal neuron. This interaction is probably mostly responsible for the locomotor depressant and activating effects of A2AR agonist and antagonists, respectively. The second type of interaction involves A2AR and D2R that do not form heteromers and takes place at the level of adenylyl cyclase (AC). Due to a strong tonic effect of endogenous dopamine on striatal D2R, this interaction keeps A2AR from signaling through AC. However, under conditions of dopamine depletion or with blockade of D2R, A2AR-mediated AC activation is unleashed with an increased gene expression and activity of the striatopallidal neuron and with a consequent motor depression. This interaction is probably the main mechanism responsible for the locomotor depression induced by D2R antagonists. Finally, striatal A2ARs are also localized presynaptically, in cortico-striatal glutamatergic terminals that contact the striato-nigral MSN. These presynaptic A2ARs heteromerize with A1 receptors (A1Rs) and their activation facilitates glutamate release. These three different types of A2ARs can be pharmacologically dissected by their ability to bind ligands with different affinity and can therefore provide selective targets for drug development in different basal ganglia disorders. PMID:21731559

  13. Unraveling mechanisms underlying partial agonism in 5-HT3A receptors.

    PubMed

    Corradi, Jeremías; Bouzat, Cecilia

    2014-12-10

    Partial agonists have emerged as attractive therapeutic molecules. 2-Me-5HT and tryptamine have been defined as partial agonists of 5-HT3 receptors on the basis of macroscopic measurements. Because several mechanisms may limit maximal responses, we took advantage of the high-conductance form of the mouse serotonin type 3A (5-HT3A) receptor to understand their molecular actions. Individual 5-HT-bound receptors activate in long episodes of high open probability, consisting of groups of openings in quick succession. The activation pattern is similar for 2-Me-5HT only at very low concentrations since profound channel blockade takes place within the activating concentration range. In contrast, activation episodes are significantly briefer in the presence of tryptamine. Generation of a full activation scheme reveals that the fully occupied receptor overcomes transitions to closed preopen states (primed states) before opening. Reduced priming explains the partial agonism of tryptamine. In contrast, 2-Me-5HT is not a genuine partial agonist since priming is not dramatically affected and its low apparent efficacy is mainly due to channel blockade. The analysis also shows that the first priming step is the rate-limiting step and partial agonists require an increased number of priming steps for activation. Molecular docking suggests that interactions are similar for 5-HT and 2-Me-5HT but slightly different for tryptamine. Our study contributes to understanding 5-HT3A receptor activation, extends the novel concept of partial agonism within the Cys-loop family, reveals novel aspects of partial agonism, and unmasks molecular actions of classically defined partial agonists. Unraveling mechanisms underlying partial responses has implications in the design of therapeutic compounds.

  14. Endothelin plays a role in contractions of isolated pig pulmonary vessels induced by diaspirin cross-linked hemoglobin.

    PubMed

    Ledvina, M A; Hart, J; Bina, S; Jing, M; Muldoon, S

    1999-05-01

    The current studies were undertaken to investigate the role of endothelin-1 (ET-1) and its receptors in contractions of isolated pulmonary vessels of the pig induced by diaspirin cross-linked hemoglobin (DCLHb). Second-order pulmonary arteries (PAs) and veins (PVs) were isolated from pigs, cut into rings (4 to 5 mm), and mounted at optimal passive tension in 37 degrees C Krebs-filled tissue baths bubbled with 95% O2/5% CO2. Isometric tension was recorded continuously. In paired rings, concentration responses to ET-1 (10(-10) to 10(-7) mol/L), DCLHb (10(-9) to 3x10(-6) mol/L), and N-nitro-L-arginine (LNA) (10(-6) to 5x10(-5) mol/L) in the presence and absence of the ET(A) receptor antagonist BQ123 (3x10(-5) mol/L) were determined. PVs and PAs with intact endothelium and rings from which the endothelium was removed (denuded) were pretreated with the ET(B) receptor antagonist BQ788 to determine the contribution of ET(B) receptors to ET-1, DCLHb, and LNA responses. ET-1, DCLHb, and LNA caused concentration-dependent increases in tension in all vessels. In the presence of BQ123, the 50% effective concentration (EC50) of ET-1 was significantly increased (by 5-fold to 10-fold) in all vessels. DCLHb concentration responses were significantly attenuated-in the PVs by 45% and in the PAs by 79%-during treatment with BQ123. BQ123 attenuated LNA responses in PVs by 35% and in PAs by 87%. Treatment with BQ788 had no effect on endothelium-intact PVs or PAs but significantly increased ET-1 EC50 (log of the molar concentration) from -9.0+/-0.22 to -7.8+/-0.05 in denuded PAs. The ET-1 EC50 was significantly decreased in denuded PAs (-9.0+/-0.22) as compared with responses in endothelium-intact PAs (-8.1+/-0.18). DCLHb concentration responses were attenuated by 71% and LNA responses by 80% during antagonism with BQ788 in the intact PAs only. These data demonstrate that ET-1 plays a role in DCLHb-induced contractions in the PA and PV. The contributions of ET are mediated by both ET

  15. [Comparative analysis of metabotropic and ionotropic glutamate striatal receptors blockade influence on rats locomotor behaviour].

    PubMed

    Iakimovskiĭ, A F; Kerko, T V

    2013-02-01

    The influence of NMDA and metabotropic neostriatal glutamate receptors blockade to avoidance conditioning (in shuttle box) and free locomotor behavior (in open field) in chronic experiments in rats were investigated. The glutamate receptor antagonists were injected bilateral into striatum separately and with the GABA-A receptor antagonist picrotoxin (2 microg), that produced in rats the impairment of avoidance conditioning and choreo-myoklonic hyperkinesis. The most effective in preventing of negative picrotoxin influence on behavior was 5-type metabotropic glutamate receptors antagonist MTEP (3 microg). Separately injected MTEP did not influence on avoidance conditioning and free locomotor behavior. Unlike that, 1-type metabotropic glutamate receptors antagonist EMQMCM (3 microg) impaired normal locomotor behavior and did not prevent the picrotoxin effects. The NMDA glutamate receptors MK 801 (disocilpin--1 and 5 microg) impaired the picrotoxin-induced hyperkinesis, but did not to prevent the negative effects on avoidance conditioning; separately injected MK 801 reduced free locomotor activity. Based on location of investigated receptor types in neostriatal neurons membranes, we proposed that the most effective influence on 5-type metabotropic glutamate receptors is associated with their involvement in "indirect" efferent pathway, suffered in hyperkinetic extrapyramidal motor dysfunction--Huntington's chorea in human.

  16. Glucose-dependent insulinotropic peptide stimulates thymidine incorporation in endothelial cells: role of endothelin-1

    NASA Technical Reports Server (NTRS)

    Ding, Ke-Hong; Zhong, Qing; Isales, Carlos M.; Iscules, C. M. (Principal Investigator)

    2003-01-01

    We have previously characterized the receptor for glucose-dependent insulinotropic polypeptide (GIPR) in vascular endothelial cells (EC). Different EC types were found to contain distinct GIPR splice variants. To determine whether activation of the GIPR splice variants resulted in different cellular responses, we examined GIP effects on human umbilical vein endothelial cells (HUVEC), which contain two GIPR splice variants, and compared them with a spontaneously transformed human umbilical vein EC line, ECV 304, which contains four GIPR splice variants. GIP dose-dependently stimulated HUVEC and ECV 304 proliferation as measured by [3H]thymidine incorporation. GIP increased endothelin-1 (ET-1) secretion from HUVEC but not from ECV 304. Use of the endothelin B receptor blocker BQ-788 resulted in an inhibition of [3H]thymidine incorporation in HUVEC but not in ECV 304. These findings suggest that, although GIP increases [3H]thymidine incorporation in both HUVEC and ECV 304, this proliferative response is mediated by ET-1 only in HUVEC. These differences in cellular response to GIP may be related to differences in activation of GIPR splice variants.

  17. Adaptations of the endothelin system after exercise training in a porcine model of ischemic heart disease

    PubMed Central

    Robles, Juan Carlos; Heaps, Cristine L.

    2014-01-01

    Objective Test the hypothesis that exercise training would increase endothelin-mediated vasoconstriction in collateral-dependent arteries via enhanced contribution of ETA. Methods An ameroid constrictor was surgically placed around the proximal LCX artery to induce gradual occlusion in Yucatan miniature swine. Eight-weeks postoperatively, pigs were randomized into sedentary or exercise-training (treadmill; 5 days/wk; 14 wks) groups. Subsequently, arteries (~150 μm diameter) were isolated from collateral-dependent and nonoccluded myocardial regions and studied. Results Following exercise training, ET-1-mediated contraction was significantly enhanced in collateral-dependent arteries. Exercise training induced a disproportionate increase in the ETA contribution to the ET-1 contractile response in collateral-dependent arteries, with negligible contributions by ETB. In collateral-dependent arteries of sedentary pigs, inhibition of ETA or ETB did not significantly alter ET-1 contractile responses in collateral-dependent arteries, suggesting compensation by the functionally active receptor. These adaptations occurred without significant changes in ETA, ETB, or ECE mRNA levels but with significant exercise training-induced elevations in endothelin levels in both nonoccluded and collateral-dependent myocardial regions Conclusions Taken together, these data reveal differential adaptive responses in collateral-dependent arteries based upon physical activity level. ETA and ETB appear to compensate for one another to maintain contraction in sedentary pigs, whereas exercise-training favors enhanced contribution of ETA. PMID:25220869

  18. Contribution of endothelin-1 to the enhanced carotid body chemosensory responses induced by chronic intermittent hypoxia.

    PubMed

    Rey, Sergio; Del Rio, Rodrigo; Iturriaga, Rodrigo

    2006-05-01

    Chronic intermittent hypoxia (CIH) enhances carotid body (CB) chemosensory responses to acute hypoxia. We tested the hypothesis that endothelin-1 (ET-1), an excitatory modulator of CB chemoreception may contribute to the enhanced CB chemosensory responses in cats exposed to cyclic hypoxic episodes repeated during 8 h for 4 days. Accordingly, we measured the ET-1 immunoreactivity (ET-ir) in the CB and plasma. Using a perfused CB preparation, we studied the effects of exogenous ET-1 and bosentan, a non-selective endothelin receptor type A and B antagonist, on the frequency of chemosensory discharges (f(x)) during normoxia, mild and severe hypoxia. We found that CIH increased ET-ir in the CB by approximately 10-fold leaving ET-1 plasma levels unchanged. Application of ET-1 to control and CIH-treated CBs produced long-lasting dose-dependent increases in f(x), although the dose-response curve showed a rightward-shift in the CIH-treated CBs. CIH increased baseline f(x) and hypoxic chemosensory responses, which were reduced by 50 microM bosentan in CBs from CIH-treated cats. Present results suggest that a local increase of ET-1 in the CB may contribute to the enhanced chemosensory responses induced by CIH predominantly through a vasomotor mechanism.

  19. Effects of environmental salinity on gill endothelin receptor expression in the killifish, Fundulus heteroclitus.

    PubMed

    Hyndman, Kelly A; Evans, David H

    2009-01-01

    We recently determined that rapid changes in environmental salinity alter endothelin-1 (EDN1) mRNA levels in the euryhaline killifish, Fundulus heteroclitus, so we hypothesized that EDN1 may be a local regulator of gill ion transport in teleost fishes. The purpose of the present study was to examine the effects of changes in environmental salinity on the gill endothelin receptors: EDNRA, EDNRB, and EDNRC. Using quantitative real-time PCR, we determined that after a fresh water (FW) to seawater (SW) transfer, there is a two to threefold increase in gill EDNRA and EDNRB mRNA levels. Likewise, we found a two to three fold increase in gill EDNRA and EDNRB protein concentration. In addition, killifish that have acclimated to FW for 30 days had significantly lower EDNRA mRNA and protein levels than SW killifish. ENDRA were immunolocalized to the mitochondrion-rich cells of the killifish gill, suggesting that EDN1 signaling cascades may affect MRC function. EDNRB were found throughout the gill vasculature and on lamellar pillar cells. We previously immunolocalized EDN1 to the pillar cell suggesting that EDN1 acts as an autocrine signaling molecule and potentially regulates pillar cell tone and lamellar perfusion. We conclude that EDN1 is physiologically active in the teleost gill, and regulated by environmental salinity. Future functional studies examining the physiological role of this system are necessary to completely understand EDN1 in the fish gill.

  20. Tezosentan, an endothelin receptor antagonist, limits liver injury in endotoxin challenged cirrhotic rats

    PubMed Central

    Urbanowicz, W; Sogni, P; Moreau, R; Tazi, K A; Barriere, E; Poirel, O; Martin, A; Guimont, M C; Cazals-Hatem, D; Lebrec, D

    2004-01-01

    Background/aims: Lipopolysaccharide (LPS) induces liver injury which is associated with upregulated endothelin (ET)-1 production. The aim of this study was to investigate the effects of tezosentan, a non-selective ETA and ETB receptor antagonist, in LPS challenged rats with cirrhosis. Methods: Rats with cirrhosis received LPS and then tezosentan or placebo one hour later. Four hours after LPS administration, rats were killed to measure serum transaminase activity and plasma tumour necrosis factor α (TNF-α) levels. Hepatic inducible nitric oxide synthase (iNOS), myeloperoxidase (MPO), a marker of neutrophil infiltration, and cyclooxygenase (COX)-2 expression were also measured. Results: LPS administration significantly decreased arterial pressure and significantly increased plasma endothelin levels. Following LPS and tezosentan administration, serum aspartate aminotransferase and alanine aminotransferase activities were similar to those in the control group while they were increased by more than 700% with LPS alone. Plasma TNF-α levels were significantly lower in rats receiving LPS and tezosentan (182 (38) pg/ml) compared with those receiving LPS alone (821 (212) pg/ml). Tezosentan significantly decreased hepatic MPO activity and hepatic neutrophils but had no effect on LPS induced iNOS or COX-2. Survival rate was significantly higher in rats receiving LPS plus tezosentan (80%) than in rats receiving LPS alone (50%). Conclusion: In LPS challenged cirrhotic rats, tezosentan administration prevents LPS induced liver injury by decreasing intrahepatic neutrophil infiltration. In addition, tezosentan increases survival in these rats. PMID:15542526

  1. Endothelin-converting enzyme is a plausible target gene for hypoxia-inducible factor.

    PubMed

    Khamaisi, Mogher; Toukan, Hala; Axelrod, Jonathan H; Rosenberger, Christian; Skarzinski, Galia; Shina, Ahuva; Meidan, Rina; Koesters, Robert; Rosen, Seymour; Walkinshaw, Gail; Mimura, Imari; Nangaku, Masaomi; Heyman, Samuel N

    2015-04-01

    Renal endothelin-converting enzyme (ECE)-1 is induced in experimental diabetes and following radiocontrast administration, conditions characterized by renal hypoxia, hypoxia-inducible factor (HIF) stabilization, and enhanced endothelin synthesis. Here we tested whether ECE-1 might be a HIF-target gene in vitro and in vivo. ECE-1 transcription and expression increased in cultured vascular endothelial and proximal tubular cell lines, subject to hypoxia, to mimosine or cobalt chloride. These interventions are known to stabilize HIF signaling by inhibition of HIF-prolyl hydroxylases. In rats, HIF-prolyl-hydroxylase inhibition by mimosine or FG-4497 increased HIF-1α immunostaining in renal tubules, principally in distal nephron segments. This was associated with markedly enhanced ECE-1 protein expression, predominantly in the renal medulla. A progressive and dramatic increase in ECE-1 immunostaining over time, in parallel with enhanced HIF expression, was also noted in conditional von Hippel-Lindau knockout mice. Since HIF and STAT3 are cross-stimulated, we triggered HIF expression by STAT3 activation in mice, transfected by or injected with a chimeric IL-6/IL-6-receptor protein, and found a similar pattern of enhanced ECE-1 expression. Chromatin immunoprecipitation sequence (ChIP-seq) and PCR analysis in hypoxic endothelial cells identified HIF binding at the ECE-1 promoter and intron regions. Thus, our findings suggest that ECE-1 may be a novel HIF-target gene.

  2. Collecting duct-specific knockout of the endothelin B receptor causes hypertension and sodium retention.

    PubMed

    Ge, Yuqiang; Bagnall, Alan; Stricklett, Peter K; Strait, Kevin; Webb, David J; Kotelevtsev, Yuri; Kohan, Donald E

    2006-12-01

    Collecting duct (CD)-derived endothelin-1 (ET-1) inhibits renal Na reabsorption and its deficiency increases blood pressure (BP). The role of CD endothelin B (ETB) receptors in mediating these effects is unknown. CD-specific knockout of the ETB receptor was achieved using an aquaporin-2 promoter-Cre recombinase transgene and the loxP-flanked ETB receptor gene (CD ETB KO). Systolic BP in mice with CD-specific knockout of the ETB receptor, ETA receptor (CD ETA KO) and ET-1 (CD ET-1 KO), and their respective controls were compared during normal- and high-salt diet. On a normal-sodium diet, CD ETB KO mice had elevated BP, which increased further during high salt feeding. However, the degree of hypertension in CD ETB KO mice and the further increase in BP during salt feeding were lower than that of CD ET-1 KO mice, whereas CD ETA KO mice were normotensive. CD ETB KO mice had impaired sodium excretion following acute sodium loading. Aldosterone and plasma renin activity were decreased in CD ETB KO mice on normal- and high-sodium diets, while plasma and urinary ET-1 levels did not differ from controls. In conclusion, the CD ETB receptor partially mediates the antihypertensive and natriuretic effects of ET-1. CD ETA and ETB receptors do not fully account for the antihypertensive and natriuretic effects of CD-derived ET-1, suggesting paracrine effects of this peptide.

  3. Hemorrhage-induced Vascular Hyporeactivity to Norepinephrine in Select Vasculatures of Rats and the Roles of Nitric Oxide and Endothelin

    DTIC Science & Technology

    2003-03-01

    Hepatology 27:755– 764, 1998. 20. Iglarz M, Levy BI, Henrion D: Chronic endothelin-1 induced changes in vascu- lar reactivity in rat resistance...Mitchell JA, Vane JR: Vascular hyporeactivity to vasoconstrictor agents and hemodynamic decompensation in hemorrhagic shock is mediated by nitric oxide

  4. Isoforms of endothelin-converting enzyme-1 (ECE-1) have opposing effects on prostate cancer cell invasion.

    PubMed

    Lambert, L A; Whyteside, A R; Turner, A J; Usmani, B A

    2008-10-07

    Cross-talk between tumour and stromal cells can profoundly influence cancer cell invasion by increasing the availability of mitogenic peptides such as endothelin-1 (ET-1). Endothelin-1 is elevated in men with metastatic prostate cancer (PC), and can exert both an autocrine (epithelial) and a paracrine (stromal) influence on growth. Endothelin-1 is generated from its inactive precursor big-ET-1 by endothelin-converting enzyme 1 (ECE-1). We and others have demonstrated that ECE-1 expression is significantly elevated in tumours and surrounding stromal tissue. Our current data show siRNA-mediated knockdown of stromal ECE-1 reduces epithelial (PC-3) cell invasion in coculture. Interestingly, readdition of ET-1 only partially recovers this effect suggesting a novel role for ECE-1 independent of ET-1 activation. Parallel knockdown of ECE-1 in both stromal and epithelial compartments results in an additive decrease in cell invasion. We extrapolated this observation to the four recognised isoforms ECE-1a, ECE-1b, ECE-1c and ECE-1d. Only ECE-1a and ECE-1c were significant but with reciprocal effects on cell invasion. Transient ECE-1c overexpression increased PC-3 invasiveness through matrigel, whereas transient ECE-1a expression suppressed invasion. Furthermore, transient ECE-1a expression in stromal cells strongly counteracts the effect of transient ECE-1c expression in PC-3 cells. The ECE-1 isoforms may, therefore, be relevant targets for antiinvasive therapy in prostate and other cancers.

  5. Utilizing a cranial window to visualize the middle cerebral artery during endothelin-1 induced middle cerebral artery occlusion.

    PubMed

    Regenhardt, Robert W; Ansari, Saeed; Azari, Hassan; Caldwell, Kenneth J; Mecca, Adam P

    2013-02-22

    Creation of a cranial window is a method that allows direct visualization of structures on the cortical surface of the brain(1-3). This technique can be performed in many locations overlying the rat cerebrum, but is most easily carried out by creating a craniectomy over the readily accessible frontal or parietal bones. Most frequently, we have used this technique in combination with the endothelin-1 middle cerebral artery occlusion model of ischemic stroke to quantify the changes in middle cerebral artery vessel diameter that occur with injection of endothelin-1 into the brain parenchyma adjacent to the proximal MCA(4, 5). In order to visualize the proximal portion of the MCA during endothelin -1 induced MCAO, we use a technique to create a cranial window through the temporal bone on the lateral aspect of the rat skull (Figure 1). Cerebral arteries can be visualized either with the dura intact or with the dura incised and retracted. Most commonly, we leave the dura intact during visualization since endothelin-1 induced MCAO involves delivery of the vasoconstricting peptide into the brain parenchyma. This bypasses the need to incise the dura directly over the visualized vessels for drug delivery. This protocol will describe how to create a cranial window to visualize cerebral arteries in a step-wise fashion, as well as how to avoid many of the potential pitfalls pertaining to this method.

  6. Conductance of a proximitized nanowire in the Coulomb blockade regime

    NASA Astrophysics Data System (ADS)

    van Heck, B.; Lutchyn, R. M.; Glazman, L. I.

    2016-06-01

    We identify the leading processes of electron transport across finite-length segments of proximitized nanowires and build a quantitative theory of their two-terminal conductance. In the presence of spin-orbit interaction, a nanowire can be tuned across the topological transition point by an applied magnetic field. Due to a finite segment length, electron transport is controlled by the Coulomb blockade. Upon increasing of the field, the shape and magnitude of the Coulomb blockade peaks in the linear conductance are defined, respectively, by Andreev reflection, single-electron tunneling, and resonant tunneling through the Majorana modes emerging after the topological transition. Our theory provides the framework for the analysis of experiments with proximitized nanowires [such as reported in S. M. Albrecht et al., Nature (London) 531, 206 (2016), 10.1038/nature17162] and identifies the signatures of the topological transition in the two-terminal conductance.

  7. Combination Approaches with Immune-Checkpoint Blockade in Cancer Therapy.

    PubMed

    Swart, Maarten; Verbrugge, Inge; Beltman, Joost B

    2016-01-01

    In healthy individuals, immune-checkpoint molecules prevent autoimmune responses and limit immune cell-mediated tissue damage. Tumors frequently exploit these molecules to evade eradication by the immune system. Over the past years, immune-checkpoint blockade of cytotoxic T lymphocyte antigen-4 and programed death-1 emerged as promising strategies to activate antitumor cytotoxic T cell responses. Although complete regression and long-term survival is achieved in some patients, not all patients respond. This review describes promising, novel combination approaches involving immune-checkpoint blockade in the context of the cancer-immunity cycle, aimed at increasing response rates to the single treatments. Specifically, we discuss combinations that promote antigen release and presentation, that further amplify T cell activation, that inhibit trafficking of regulatory T cells or MSDCs, that stimulate intratumoral T cell infiltration, that increase cancer recognition by T cells, and that stimulate tumor killing.

  8. Immunogenic chemotherapy sensitizes tumors to checkpoint blockade therapy

    PubMed Central

    Pfirschke, Christina; Engblom, Camilla; Rickelt, Steffen; Cortez-Retamozo, Virna; Garris, Christopher; Pucci, Ferdinando; Yamazaki, Takahiro; Colame, Vichnou Poirier; Newton, Andita; Redouane, Younes; Lin, Yi-Jang; Wojtkiewicz, Gregory; Iwamoto, Yoshiko; Mino-Kenudson, Mari; Huynh, Tiffany G.; Hynes, Richard O.; Freeman, Gordon J.; Kroemer, Guido; Zitvogel, Laurence; Weissleder, Ralph; Pittet, Mikael J.

    2016-01-01

    SUMMARY Checkpoint blockade immunotherapies can be extraordinarily effective, but may benefit only the minority of patients whose tumors are pre-infiltrated by T cells. Here, using lung adenocarcinoma mouse models, including genetic models, we show that autochthonous tumors that lacked T cell infiltration and resisted current treatment options could be successfully sensitized to host antitumor T cell immunity when using appropriately selected immunogenic drugs (e.g. oxaliplatin combined with cyclophosphamide for treatment against tumors expressing oncogenic Kras and lacking Trp53). The antitumor response was triggered by direct drug actions on tumor cells, relied on innate immune sensing through toll-like receptor 4 signaling, and ultimately depended on CD8+ T cell antitumor immunity. Furthermore, instigating tumor infiltration by T cells sensitized tumors to checkpoint inhibition and controlled cancer durably. These findings indicate that the proportion of cancers responding to checkpoint therapy can be feasibly and substantially expanded by combining checkpoint blockade with immunogenic drugs. PMID:26872698

  9. Combination Approaches with Immune-Checkpoint Blockade in Cancer Therapy

    PubMed Central

    Swart, Maarten; Verbrugge, Inge; Beltman, Joost B.

    2016-01-01

    In healthy individuals, immune-checkpoint molecules prevent autoimmune responses and limit immune cell-mediated tissue damage. Tumors frequently exploit these molecules to evade eradication by the immune system. Over the past years, immune-checkpoint blockade of cytotoxic T lymphocyte antigen-4 and programed death-1 emerged as promising strategies to activate antitumor cytotoxic T cell responses. Although complete regression and long-term survival is achieved in some patients, not all patients respond. This review describes promising, novel combination approaches involving immune-checkpoint blockade in the context of the cancer-immunity cycle, aimed at increasing response rates to the single treatments. Specifically, we discuss combinations that promote antigen release and presentation, that further amplify T cell activation, that inhibit trafficking of regulatory T cells or MSDCs, that stimulate intratumoral T cell infiltration, that increase cancer recognition by T cells, and that stimulate tumor killing. PMID:27847783

  10. Lifting the Franck-Condon blockade in driven quantum dots

    NASA Astrophysics Data System (ADS)

    Haughian, Patrick; Walter, Stefan; Nunnenkamp, Andreas; Schmidt, Thomas L.

    2016-11-01

    Electron-vibron coupling in quantum dots can lead to a strong suppression of the average current in the sequential tunneling regime. This effect is known as Franck-Condon blockade and can be traced back to an overlap integral between vibron states with different electron numbers which becomes exponentially small for large electron-vibron coupling strength. Here, we investigate the effect of a time-dependent drive on this phenomenon, in particular the effect of an oscillatory gate voltage acting on the electronic dot level. We employ two different approaches: perturbation theory based on nonequilibrium Keldysh Green's functions and a master equation in Born-Markov approximation. In both cases, we find that the drive can lift the blockade by exciting vibrons. As a consequence, the relative change in average current grows exponentially with the drive strength.

  11. Pauli spin blockade in CMOS double quantum dot devices

    NASA Astrophysics Data System (ADS)

    Kotekar-Patil, D.; Corna, A.; Maurand, R.; Crippa, A.; Orlov, A.; Barraud, S.; Hutin, L.; Vinet, M.; Jehl, X.; De Franceschi, S.; Sanquer, M.

    2017-03-01

    Silicon quantum dots are attractive candidates for the development of scalable, spin-based qubits. Pauli spin blockade in double quantum dots provides an efficient, temperature independent mechanism for qubit readout. Here we report on transport experiments in double gate nanowire transistors issued from a CMOS process on 300 mm silicon-on-insulator wafers. At low temperature the devices behave as two few-electron quantum dots in series. We observe signatures of Pauli spin blockade with a singlet-triplet splitting ranging from 0.3 to 1.3 meV. Magneto-transport measurements show that transitions which conserve spin are shown to be magnetic-field independent up to B = 6 T.

  12. Study on Neuromuscular Blockade Action of Verapamil in Albino Rats

    PubMed Central

    Nagaral, Jayashree; GH, Shashikala; K, Jagadeesh; Kumar K, Sharath; GS, Jayanth; PK, Chennaveerappa; Patil, Rajani

    2013-01-01

    Background: Calcium Channel Blockers (CCBs) are now widely employed in the treatment of cardiovascular diseases and peri operative hypertension. It has been reported that calcium channel blockers inhibit neuromuscular transmission. They have been shown to increase the neuromuscular blockade produced by neuromuscular blocking agents in in-vitro muscle nerve preparations. The present study is undertaken to demonstrate the effect of calcium channel blocker, verapamil on neuromuscular transmission in albino rats. Objectives: To study the neuromuscular blockade action of verapamil in albino rats. Methods: Twenty four albino rats of either sex weigh 150-250gms are selected and are randomly divided into 4 equal groups. The experimental rats are divided into four groups of 6 rats each and they are given the following treatment. Group 1(Control) - Normal saline (1ml/ kg), Group 2 (Standard) - Pancuronium (0.04 mg/kg) Group 3-Verapamil (2.5mg/kg), Group 4-given Verapamil (10mg/kg). The time of onset of hind limb paralysis and total duration of recovery are noted using inclined screen method. Results: Analysis of the results of group 3 that was received 2.5mg/kg of Verapamil, there was no onset of paralysis, in group 4 that received injection Verapamil 10mg/kg, showed neuromuscular blockade activity. The mean onset of hind limb paralysis was delayed compared to standard group and the mean duration of hind limb paralysis was shorter than standard group. It was statistically significant (P≤ 0.05). Interpretation and conclusion: It is generally held that external calcium is not necessary for the contraction of mammalian skeletal muscle, the demonstration of inward calcium currents that can be abolished by CCBs in these muscles prompted to re-examine the effect of Verapamil on the neuromuscular transmission. The present study allows us to determine the neuromuscular blockade activity of Verapamil. PMID:24086855

  13. Different endothelin receptors involved in endothelin-1- and sarafotoxin S6B-induced contractions of the human isolated coronary artery.

    PubMed Central

    Bax, W A; Aghai, Z; van Tricht, C L; Wassenaar, C; Saxena, P R

    1994-01-01

    1. Endothelin receptors, that mediate contraction of the human isolated coronary artery, were characterized by use of a number of agonists and antagonists. Contraction induced by the non-selective agonists, endothelin (ET)-1 and sarafotoxin S6b, was compared in endothelium-intact and endothelium-denuded ring segments. The effects of ET-1 and BQ-123 (an ETA receptor antagonist) were investigated both in ring segments and in spirally cut strips. Lastly, the effect of phosphoramidon was studied on contraction induced by big-ET-1. 2. The order of agonist potency (pD2) in endothelium-intact coronary artery ring segments was: ET-1 (8.27) approximately sarafotoxin S6b (8.16) > big-ET-1 (< 7.1) approximately ET-3 (< 6.9). [Ala1,3,11,15]ET-1 (ETB receptor agonist) caused significant contraction only at 1 microM, whereas 0.3 microM big-ET-3 had no effect. Removal of the endothelium in ring segments did not affect the contractile response to ET-1 or to sarafotoxin S6b. 3. After a full concentration-response curve had been obtained to ET-1 or sarafotoxin S6b, further contractions of the endothelium-intact coronary artery segments could only be achieved by applying ET-1 in segments exposed to sarafotoxin S6b, and not the reverse. 4. BQ-123 (0.1 microM) antagonized contractions of endothelium-intact ring segments induced by sarafotoxin S6b (pKB 7.86). Only 10 microM BQ-123 antagonized contractions induced by ET-1 (pKB 5.75). FR139317 was also more potent against sarafotoxin S6b (pKB 8.24-8.47) than against ET-1 (pKB 6.11). [Ala1,3,11,15]ET-1 (1 microM) had no effect on the contractile response to ET-1 or to sarafotoxin S6b.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7889304

  14. Endothelin-like action of Pausinystalia yohimbe aqueous extract on vascular and renal regional hemodynamics in Sprague Dawley rats.

    PubMed

    Ajayi, A A; Newaz, M; Hercule, H; Saleh, M; Bode, C O; Oyekan, A O

    2003-12-01

    The bark of the African tree Pausinystalia yohimbe has been used as a food additive with aphrodisiac and penile erection enhancing properties. The effect of an aqueous extract of P. yohimbe (CCD-X) on renal circulation was assessed in order to test the hypothesis that it possesses additional effects on nitric oxide production and/or endothelin-1 (ET-1)-like actions. In vivo studies with CCD-X in Sprague Dawley rats demonstrated a dose-dependent (1-1000 ng/kg) increase in mean blood pressure (p < 0.001) and an increase in medullary blood flow (MBF) (p < 0.001). Both the pressor action and renal medullary vasodilation were blocked by endothelinA (ETA) receptor antagonist BMS182874 and endothelinB (ETB) receptor antagonist BQ788 in combination. L-Nomega-nitro-l-arginine methyl ester (L-NAME; 10 mg/kg) also inhibited the increase in MBF induced by CCD-X. In vitro studies in isolated perfused kidney and in pressurized renal microvessels confirmed the dose-dependent vasoconstrictor action of this extract. ETA receptor antagonist BQ610 and ETB receptor antagonist BQ788 separately and significantly attenuated the renal vasoconstrictor actions of the extract (p < 0.001 ANOVA). These preliminary observations indicate that, in addition to the alpha-adrenergic antagonist actions that characterize yohimbine, CCD-X possesses endothelin-like actions and affects nitric oxide (NO) production in renal circulation. These findings suggest a strong possibility of post-receptor cross-talk between alpha2-adrenoceptors and endothelin, as well as a direct effect of alpha2-adrenoceptors on renal NO production.

  15. Coronary action of endothelin-1 and vasopressin during acute hypertension in anesthetized goats. Role of nitric oxide and prostanoids.

    PubMed

    Fernández, Nuria; Martínez, María Angeles; García-Villalón, Angel Luis; Monge, Luis; Diéguez, Godofredo

    2004-01-01

    Coronary reactivity to endothelin-1 and vasopressin during acute, moderate hypertension, and the role of nitric oxide (NO) and prostanoids in this reactivity was examined in anesthetized goats. Left circumflex coronary flow was electromagnetically measured, and hypertension was induced by constriction of the thoracic aorta in animals nontreated (7 goats) or treated with the inhibitor of NO synthesis Nw-nitro-L-arginine methyl esther (L-NAME, 6 goats) or the cyclooxygenase inhibitor meclofenamate (6 goats). Under normotension (19 animals), basal mean values for mean arterial pressure and coronary vascular conductance (CVC) were 89+/-3 mm Hg and 0.36+/-0.038 ml/min/mm Hg, respectively. Endothelin-1 (0.01-0.3 nmol) and vasopressin (0.03-1 microg) dose-dependently decreased CVC, which, for endothelin-1 ranged from 5+/-1% (0.01 nmol; P<0.01) to 66+/-4% (0.3 nmol; P<0.001) and for vasopressin ranged from 9+/-1% (0.03 microg P<0.01) to 41+/-3% (1 microg; P<0.001). During nontreated and treated hypertension, mean arterial pressure increased to approximately 130 mmHg (P<0.01), and CVC decreased (17%) only during L-NAME-treated hypertension. The effects of endothelin-1 and vasopressin on CVC were decreased by approximately 50% during nontreated hypertension, and this was abolished by L-NAME and was not affected by meclofenamate. Therefore, during acute, moderate hypertension, the coronary vasoconstriction to endothelin-1 and vasopressin is attenuated, which may be related with increased NO release but not with prostanoids.

  16. Beta-adrenergic blockade and atrio--ventricular conduction impairment.

    PubMed

    Giudicelli, J F; Lhoste, F; Boissier, J R

    1975-04-01

    Atrio--ventricular conduction and its modifications induced by six Beta-adrenergic blocking agents have been investigated in the dog. Premature atrial stimuli (St2) were applied at variable intervals following regular stimuli (St1) ensuring atrial pacing; atrial (AERP), nodoventricular (NERP) and global (GERP) effective refractory periods as well as global functional refractory period (GFRP) were determined before and after administration of each of the six drugs. When Beta-blockade was produced with d,1-propranolol which hwas membrane stabilizing effects (MSE) but no intrinsic sympathomimetic activity (ISA) or with sotalol, which has neither MSE nor ISA, all parameters were significantly increased. When Beta-blockade was achieved with pindolol or practolol, which have only a poor Beta-adrenolytic potency and no ISA. Alprenolol showed intermediate effects. Thus, it appears that Beta-blockade and not MSE, is responsible for the onset of A-V conduction impairment but that ISA, probably through a metabolic mechanism, affords protection against this impairment. On the other hand, measurement of ventricular effective refractory period (VERP) has shown that at the Purkinje-free junction, it is MSE which is mainly involved in conduction impairment.

  17. PD-1 blockade expands intratumoral T memory cells

    PubMed Central

    Ribas, Antoni; Shin, Daniel Sanghoon; Zaretsky, Jesse; Frederiksen, Juliet; Cornish, Andrew; Avramis, Earl; Seja, Elizabeth; Kivork, Christine; Siebert, Janet; Kaplan-Lefko, Paula; Wang, Xiaoyan; Chmielowski, Bartosz; Glaspy, John A.; Tumeh, Paul C.; Chodon, Thinle; Pe’er, Dana; Comin-Anduix, Begoña

    2016-01-01

    Tumor responses to PD-1 blockade therapy are mediated by T cells, which we characterized in 102 tumor biopsies obtained from 53 patients treated with pembrolizumab, an antibody to PD-1. Biopsies were dissociated and single cell infiltrates were analyzed by multicolor flow cytometry using two computational approaches to resolve the leukocyte phenotypes at the single cell level. There was a statistically significant increase in the frequency of T cells in patients who responded to therapy. The frequency of intratumoral B cells and monocytic myeloid-derived suppressor cells (moMDSCs) significantly increased in patients’ biopsies taken on treatment. The percentage of cells with a T regulatory phenotype, monocytes, and NK cells did not change while on PD-1 blockade therapy. CD8+ T memory cells were the most prominent phenotype that expanded intratumorally on therapy. However, the frequency of CD4+ T effector memory cells significantly decreased on treatment, whereas CD4+ T effector cells significantly increased in nonresponding tumors on therapy. In peripheral blood, an unusual population of blood cells expressing CD56 were detected in two patients with regressing melanoma. In conclusion, PD-1 blockade increases the frequency of T cells, B cells, and MDSCs in tumors, with the CD8+ T effector memory subset being the major T-cell phenotype expanded in patients with a response to therapy. PMID:26787823

  18. Dynamical Coulomb blockade of tunnel junctions driven by alternating voltages

    NASA Astrophysics Data System (ADS)

    Grabert, Hermann

    2015-12-01

    The theory of the dynamical Coulomb blockade is extended to tunneling elements driven by a time-dependent voltage. It is shown that, for standard setups where an external voltage is applied to a tunnel junction via an impedance, time-dependent driving entails an excitation of the modes of the electromagnetic environment by the applied voltage. Previous approaches for ac driven circuits need to be extended to account for the driven bath modes. A unitary transformation involving also the variables of the electromagnetic environment is introduced which allows us to split off the time dependence from the Hamiltonian in the absence of tunneling. This greatly simplifies perturbation-theoretical calculations based on treating the tunneling Hamiltonian as a perturbation. In particular, the average current flowing in the leads of the tunnel junction is studied. Explicit results are given for the case of an applied voltage with a constant dc part and a sinusoidal ac part. The connection with standard dynamical Coulomb blockade theory for constant applied voltage is established. It is shown that an alternating voltage source reveals significant additional effects caused by the electromagnetic environment. The hallmark of the dynamical Coulomb blockade in ac driven devices is a suppression of higher harmonics of the current by the electromagnetic environment. The theory presented basically applies to all tunneling devices driven by alternating voltages.

  19. Angular momentum blockade in nanoscale high-Tc superconducting grains

    NASA Astrophysics Data System (ADS)

    Mancarella, Francesco; Balatsky, Alexander; Wallin, Mats; Rosengren, Anders; Nordita-Condensed Matter Collaboration; KTH-Theoretical Physics Collaboration

    2014-03-01

    We discuss the angular momentum blockade in small d-wave SC grains in an external magnetic field. We find abrupt changes in angular momentum state of the condensate (''angular momentum blockade'') as a result of the variation of the external field. The effect represents a direct analog of the Coulomb blockade. We use the Ginzburg-Landau theory to illustrate how the field turns a d-wave order parameter (OP) into a(dx2 -y2 + idxy)-OP. We derive the volume magnetic susceptibility as a function of the field, and corresponding small jumps in magnetization at critical values of the field that should be experimentally observable in SC grains. The observation of these jumps requires a small grain, since their extent is inversely proportional to the number of Cooper pairs in the sample. The general source of instability of the pure d-wave gap is the presence of gap nodes, completely lifted by the secondary OP component. A d + id' -state is chiral and hence has an orbital moment carried by Cooper pairs. We consider fields H <

  20. Catestatin (chromogranin A344-364) is a novel cardiosuppressive agent: inhibition of isoproterenol and endothelin signaling in the frog heart.

    PubMed

    Mazza, Rosa; Gattuso, Alfonsina; Mannarino, Cinzia; Brar, Bhawanjit K; Barbieri, Sandra Francesca; Tota, Bruno; Mahata, Sushil K

    2008-07-01

    The catecholamine release-inhibitory catestatin [Cts; human chromogranin (Cg) A(352-372), bovine CgA(344-364)] is a vasoreactive and anti-hypertensive peptide derived from CgA. Using the isolated avascular frog heart as a bioassay, in which the interactions between the endocardial endothelium and the subjacent myocardium can be studied without the confounding effects of the vascular endothelium, we tested the direct cardiotropic effects of bovine Cts and its interaction with beta-adrenergic (isoproterenol, ISO) and endothelin-1 (ET-1) signaling. Cts dose-dependently decreased stroke volume and stroke work, with a threshold concentration of 11 nM, approaching the in vivo level of the peptide. Cts reduced contractility by inhibiting phosphorylation of phospholamban (PLN). Furthermore, the Cts effect was abolished by pretreatment with either nitric oxide synthase (N(G)-monomethyl-l-arginine) or guanylate cyclase (ODQ) inhibitors, or an ET(B) receptor (ET(BR)) antagonist (BQ-788). Cts also noncompetitively inhibited the positive inotropic action of ISO. In addition, Cts inhibited the positive inotropic effect of ET-1, mediated by ET(A) receptors, and did not alter the negative inotropic ET-1 influence mediated by ET(BR). Cts action through ET(BR) was further suggested when, in the presence of BQ-788, Cts failed to inhibit the positive inotropism of both ISO and ET-1 stimulation and PLN phosphorylation. We concluded that the cardiotropic actions of Cts, including the beta-adrenergic and ET-1 antagonistic effects, support a novel role of this peptide as an autocrine-paracrine modulator of cardiac function, particularly when the stressed heart becomes a preferential target of both adrenergic and ET-1 stimuli.

  1. Renal actions of endothelin-1 in newborn piglets: dose-effect relation and the effects of receptor antagonist (BQ-123) and cyclooxygenase inhibitor (indomethacin).

    PubMed

    Bhat, R; John, E; Chari, G; Shankararao, R; Fornell, L; Gulati, A; Vidyasagar, D

    1995-11-01

    Although the effects of endothelin-1 (ET-1) on intact or perfused adult kidney are well understood, its effects in the fetus and the newborn have not been well studied. We examined the effects of infusions of 25, 50, and 100 ng/kg of ET-1 per minute on mean blood pressure (MBP), cardiac index (CI), renal blood flow (RBF), glomerular filtration rate (GFR), and urine volume (UV) in 7- to 10-day-old piglets (n = 24). In addition, the effects of pretreatment with a receptor antagonist (BQ-123) and with a cyclooxygenase inhibitor (indomethacin) were studied in 12 separate piglets. ET-1 produced a dose- and level-dependent decrease in CI (60%), RBF (50% to 75%), GFR (66% to 80%) and MBP 15% to 17%. These changes returned to 75% to 80% of baseline 60 minutes after discontinuation of ET-1. Low-dose infusion (25 ng/kg) did not result in any changes in systemic or renal hemodynamics. Plasma half-life of ET-1 in piglets was 2.1 +/- 0.4 minutes. Pretreatment with the specific ETA receptor antagonist BQ-123 completely blocked the ET-1-induced systemic and renal hemodynamic changes. Indomethacin blocked the ET-1-induced rise in MBP but failed to block any renal changes. In fact, indomethacin accentuated the changes induced by ET-1, especially the changes in RBF, RVR, and GFR. Studies of receptor binding in the renal cortex and medulla showed that, in the cortex, the Ki value for ET-1 was 6.32 +/- 1.57, and for ET-3 it was 20.05 +/- 4.38 (p < 0.05); in the medulla, the Ki values were similar for both ET-1 and ET-3. These results indicate that in piglets the renal vascular bed is highly sensitive to ET-1, and its effects are predominantly mediated through ETA receptors.

  2. Involvement of nitric oxide pathways in short term modulation of tyrosine hydroxylase activity by endothelins 1 and 3 in the rat anterior hypothalamus.

    PubMed

    Morgazo, Carolina; Perfume, Guadalupe; Legaz, Guillermina; di Nunzio, Andrea; Hope, Sandra I; Bianciotti, Liliana G; Vatta, Marcelo S

    2005-09-02

    The ability of endothelins 1 and 3 (ET-1 and ET-3) to reduce neuronal norepinephrine release through ETB receptor activation involving nitric oxide (NO) pathways in the rat anterior hypothalamus region (AHR) was previously reported. In the present work, we studied the effects of ET-1 and -3 on tyrosine hydroxylase (TH) activity and the possible involvement of NO pathways. Results showed that ET-1 and -3 (10 nM) diminished TH activity in AHR and this effect was blocked by a selective ETB receptor antagonist (100 nM BQ-788), but not by a ET(A) receptor antagonist (BQ-610). To confirm these results, 1 microM IRL-1620 (ET(B) agonist) reduced TH activity whereas 300 nM sarafotoxin S6b falled to modify it. N(omega)-Nitro-L-arginine methyl ester (10 microM), 7-nitroindazole (10 microM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-ona (10 microM), KT5823 (2 microM), inhibitors of nitric oxide synthase, neuronal nitric oxide synthase, NO-sensitive-guanylyl cyclase, and protein kinase G, respectively, did not modify the reduction of TH activity produced by ETs. In addition, both 100 microM sodium nitroprusside and 50 microM 8-bromoguanosine-3',5'-cyclic monophosphate (NO donor and guanosine-3',5'-cyclic monophosphate analog, respectively) diminished TH activity. Present results showed that ET-1 and ET-3 diminished TH activity through the activation of ET(B) receptors involving the NO/guanosine-3',5'-cyclic monophosphate/protein kinase G pathway. Taken jointly present and previous results it can be concluded that both ETs play an important role as modulators of norepinephrine neurotransmission in the rat AHR.

  3. Prevention of RhoA activation and cofilin-mediated actin polymerization mediates the antihypertrophic effect of adenosine receptor agonists in angiotensin II- and endothelin-1-treated cardiomyocytes.

    PubMed

    Zeidan, Asad; Gan, Xiaohong Tracey; Thomas, Ashley; Karmazyn, Morris

    2014-01-01

    Adenosine receptor activation has been shown to be associated with diminution of cardiac hypertrophy and it has been suggested that endogenously produced adenosine may serve to blunt pro-hypertrophic processes. In the present study, we determined the effects of two pro-hypertrophic stimuli, angiotensin II (Ang II, 100 nM) and endothelin-1 (ET-1, 10 nM) on Ras homolog gene family, member A (RhoA)/Rho-associated, coiled-coil containing protein kinase (ROCK) activation in cultured neonatal rat ventricular myocytes and whether the latter serves as a target for the anti-hypertrophic effect of adenosine receptor activation. Both hypertrophic stimuli potently increased RhoA activity with peak activation occurring 15-30 min following agonist addition. These effects were associated with significantly increased phosphorylation (inactivation) of cofilin, a downstream mediator of RhoA, an increase in actin polymerization, and increased activation and nuclear import of p38 mitogen activated protein kinase. The ability of both Ang II and ET-1 to activate the RhoA pathway was completely prevented by the adenosine A1 receptor agonist N (6)-cyclopentyladenosine, the A2a receptor agonist 2-p-(2-carboxyethyl)-phenethylamino-5'-N-ethylcarboxamidoadenosine, the A3 receptor agonist N (6)-(3-iodobenzyl)adenosine-5'-methyluronamide as well as the nonspecific adenosine analog 2-chloro adenosine. All effects of specific receptor agonists were prevented by their respective receptor antagonists. Moreover, all adenosine agonists prevented either Ang II- or ET-1-induced hypertrophy, a property shared by the RhoA inhibitor Clostridium botulinum C3 exoenzyme, the ROCK inhibitor Y-27632 or the actin depolymerizing agent latrunculin B. Our study therefore demonstrates that both Ang II and ET-1 can activate the RhoA pathway and that prevention of the hypertrophic response to both agonists by adenosine receptor activation is mediated by prevention of RhoA stimulation and actin polymerization.

  4. The alpha2 adrenergic receptor antagonist idazoxan, but not the serotonin-2A receptor antagonist M100907, partially attenuated reward deficits associated with nicotine, but not amphetamine, withdrawal in rats.

    PubMed

    Semenova, Svetlana; Markou, Athina

    2010-10-01

    Based on phenomenological similarities between anhedonia (reward deficits) associated with drug withdrawal and the negative symptoms of schizophrenia, we showed previously that the atypical antipsychotic clozapine attenuated reward deficits associated with psychostimulant withdrawal. Antagonism of alpha(2) adrenergic and 5-HT(2A) receptors may contribute to these effects of clozapine. We investigated here whether blockade of alpha(2) or 5-HT(2A) receptors by idazoxan and M100907, respectively, would reverse anhedonic aspects of psychostimulant withdrawal. Idazoxan treatment facilitated recovery from spontaneous nicotine, but not amphetamine, withdrawal by attenuating reward deficits and increase the number of somatic signs. Thus, alpha(2) adrenoceptor blockade may have beneficial effects against nicotine withdrawal and may be involved in the effects of clozapine previously observed. M100907 worsened the anhedonia associated with nicotine and amphetamine withdrawal, suggesting that monotherapy with M100907 may exacerbate the expression of the negative symptoms of schizophrenia or nicotine withdrawal symptoms in people, including schizophrenia patients, attempting to quit smoking.

  5. The selective 5-HT2A receptor antagonist M100907 enhances antidepressant-like behavioral effects of the SSRI fluoxetine.

    PubMed

    Marek, Gerard J; Martin-Ruiz, Raul; Abo, Allyson; Artigas, Francesc

    2005-12-01

    The addition of low doses of atypical antipsychotic drugs, which saturate 5-HT(2A) receptors, enhances the therapeutic effect of selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors (SSRIs) in patients with major depression as well as treatment-refractory obsessive-compulsive disorder. The purpose of the present studies was to test the effects of combined treatment with a low dose of a highly selective 5-HT(2A) receptor antagonist (M100907; formerly MDL 100,907) and low doses of a SSRI using a behavioral screen in rodents (the differential-reinforcement-of low rate 72-s schedule of reinforcement; DRL 72-s) which previously has been shown to be sensitive both to 5-HT(2) antagonists and SSRIs. M100907 has a approximately 100-fold or greater selectivity at 5-HT(2A) receptors vs other 5-HT receptor subtypes, and would not be expected to appreciably occupy non-5-HT(2A) receptors at doses below 100 microg/kg. M100907 increased the reinforcement rate, decreased the response rate, and shifted the inter-response time distributions to the right in a pattern characteristic of antidepressant drugs. In addition, a positive synergistic interaction occurred when testing low doses of the 5-HT(2A) receptor antagonist (6.25-12.5 microg/kg) with clinically relevant doses of the SSRI fluoxetine (2.5-5 mg/kg), which both exerted minimal antidepressant-like effects by themselves. In vivo microdialysis study revealed that a low dose of M100907 (12.5 microg/kg) did not elevate extracellular 5-HT levels in the prefrontal cortex over those observed with fluoxetine alone (5 mg/kg). These results will be discussed in the context that the combined blockade of 5-HT(2A) receptors and serotonin transporters (SERT) may result in greater efficacy in treating neuropsychiatric syndromes than blocking either site alone.

  6. Testis dysfunction by isoproterenol is mediated by upregulating endothelin receptor A, leptin and protein kinase Cvarepsilon and is attenuated by an endothelin receptor antagonist CPU0213.

    PubMed

    Cheng, Yu-Si; Dai, De-Zai; Dai, Yin

    2010-07-01

    This study has examined whether upregulation of endothelin receptor A, leptin and phosphorylated protein kinase Cvarepsilon contributes to stress-induced testicular damaged and its possible reversal by endothelial (ET) antagonism. Adult male Sprague-Dawley rats were randomly divided into control and isoproterenol (ISO 1mg/kg, subcutaneous (s.c.), 10 days) groups, and intervened with the ET receptor antagonist CPU0213 (20mg/kg, s.c.), on days 6-10. In ISO group, testicular succinate dehydrogenase, lactate dehydrogenase, acid phosphotase, and gamma-glutamyl transpeptidase, and serum testosterone decreased, whereas FSH increased, relative to control. The seminiferous tubules were damaged in association with testicular upregulation of protein abundance of leptin and pPKCvarepsilon, and mRNA and protein expression of leptin receptor (OBRb) and ET(A). CPU0213 was effective in ameliorating these abnormalities. Over-expression of ET(A) and leptin accounting for the testis dysfunction is likely to be mediated by pPKCvarepsilon in the ISO treated rats. The upregulated ET pathway appears to be critical in pathologies of the testis.

  7. Cellular expression of isoforms of endothelin-converting enzyme-1 (ECE-1c, ECE-1b and ECE-1a) and endothelin-converting enzyme-2.

    PubMed

    Davenport, A P; Kuc, R E

    2000-11-01

    Our aim was to compare the cellular expression of endothelin-converting enzyme-1 (ECE-1) isoforms and ECE-2 using immunocytochemistry in normal and diseased human tissue. Intense ECE-1b immunoreactivity was present within renal and pulmonary epithelial cells with lower levels of staining displayed by ECE-1c, ECE-1a and ECE-2 antisera. Staining was detected with all antisera (except ECE-1a) within the endothelium of renal and pulmonary vessels having a range of lumen diameters as well as pial arteries and intracerebral vessels penetrating brain. ECE-1b, ECE-1c and ECE-2 immunoreactivity was localized to perivascular astrocytes and neuronal processes in the cerebral cortex. In diseased vessels, ECE-1c, ECE-1b and ECE-2 antisera stained macrophages infiltrating atherosclerotic plaques within coronary arteries. These results suggest ECE-1b and ECE-2 may be widely expressed in normal tissue from humans and inhibition of ECE-1 isoforms and ECE-2 expressed by cells such as macrophages in pathophysiological tissue may be an additional therapeutic target in cardiovascular disease.

  8. Plasma endothelin-1 level in athletes after exercise in a hot environment: exercise-induced dehydration contributes to increases in plasma endothelin-1.

    PubMed

    Maeda, S; Miyauchi, T; Waku, T; Koda, Y; Kono, I; Goto, K; Matsuda, M

    1996-01-01

    We investigated whether dehydration due to exercise contributes to the increase in plasma endothelin-1 (ET-1) concentration. We measured the plasma concentration of ET-1 before and after exercise in a hot environment (about 30 degrees C). Five male intercollegiate Kendo (Japanese fencing) players entered the present study. Each athlete participated in 15 min of Kendo fighting, followed by 5 min of rest and another 15 min of Kendo fighting (i.e., total exercise 30 min), with or without oral intake of 700 ml of water. Body weight and left atrial diameter, a parameter that reflects changes in circulating plasma volume, were significantly decreased after exercise under both conditions. However, the decreases in both values were significantly greater after exercise without water intake than after exercise with water intake, indicating that dehydration and decreased circulating plasma volume were more marked after exercise without water intake. The extent of the increase in plasma ET-1 concentration appeared to be closely related to the extent of exercise-induced dehydration; the greater the dehydration, the greater the increase in plasma ET-1 concentration. These findings suggest that exercise-induced dehydration may contribute to increases in plasma ET-1 concentrations.

  9. Endothelin-1-induced down-regulation of NaV1.7 expression in adrenal chromaffin cells: attenuation of catecholamine secretion and tau dephosphorylation.

    PubMed

    Nemoto, Takayuki; Yanagita, Toshihiko; Maruta, Toyoaki; Sugita, Chihiro; Satoh, Shinya; Kanai, Tasuku; Wada, Akihiko; Murakami, Manabu

    2013-04-02

    Endothelin-1 and voltage-dependent sodium channels are involved in control and suppression of neuropathological factors, which contribute to sculpting the neuronal network. We previously demonstrated that veratridine-induced NaV1.7 sodium channel activation caused intracellular calcium elevation, catecholamine secretion and tau dephosphorylation in adrenal chromaffin cells. The aim of this study was to examine whether endothelin-1 could modulate NaV1.7. Our results indicated that endothelin-1 decreased the protein level of NaV1.7 and the veratridine-induced increase in intracellular calcium. In addition, it also abolished the veratridine-induced dephosphorylation of tau and the phosphorylation of glycogen synthase kinase-3β and extracellular signal-regulated kinase. These findings suggest that the endothelin-1-induced down-regulation of NaV1.7 diminishes NaV1.7-related catecholamine secretion and dephosphorylation of tau.

  10. The effects of endothelin-1 on the cardiorespiratory physiology of the freshwater trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias).

    PubMed

    Perry, S F; Montpetit, C J; McKendry, J; Desforges, P R; Gilmour, K M; Wood, C M; Olson, K R

    2001-11-01

    The aim of the present study was to evaluate the effects of endothelin-l-elicited cardiovascular events on respiratory gas transfer in the freshwater rainbow trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias). In both species, endothelin-1 (666 pmol kg(-1)) caused a rapid (within 4 min) reduction (ca. 30-50 mmHg) in arterial blood partial pressure of O2. The effects of endothelin-1 on arterial blood partial pressure of CO2 were not synchronised with the changes in O2 partial pressure and the responses were markedly different in trout and dogfish. In trout, arterial CO2 partial pressure was increased transiently by approximately 1.0 mmHg but the onset of the response was delayed and occurred 12 min after endothelin-1 injection. In contrast, CO2 partial pressure remained more-or-less constant in dogfish after injection of endothelin-1 and was increased only slightly (approximately 0.1 mmHg) after 60 min. Pre-treatment of trout with bovine carbonic anhydrase (5 mg ml(-1)) eliminated the increase in CO2 partial pressure that was normally observed after endothelin-1 injection. In both species, endothelin-1 injection caused a decrease in arterial blood pH that mirrored the changes in CO2 partial pressure. Endothelin-1 injection was associated with transient (trout) or persistent (dogfish) hyperventilation as indicated by pronounced increases in breathing frequency and amplitude. In trout, arterial blood pressure remained constant or was decreased slightly and was accompanied by a transient increase in systemic resistance, and a temporary reduction in cardiac output. The decrease in cardiac output was caused solely by a reduction in cardiac frequency; cardiac stroke volume was unaffected. In dogfish, arterial blood pressure was lowered by approximately 10 mmHg at 6-10 min after endothelin-1 injection but then was rapidly restored to pre-injection levels. The decrease in arterial blood pressure reflected an increase in branchial vascular resistance (as

  11. Drug interactions at GABA(A) receptors.

    PubMed

    Korpi, Esa R; Gründer, Gerhard; Lüddens, Hartmut

    2002-06-01

    Neurotransmitter receptor systems have been the focus of intensive pharmacological research for more than 20 years for basic and applied scientific reasons, but only recently has there been a better understanding of their key features. One of these systems includes the type A receptor for the gamma-aminobutyric acid (GABA), which forms an integral anion channel from a pentameric subunit assembly and mediates most of the fast inhibitory neurotransmission in the adult vertebrate central nervous system. Up to now, depending on the definition, 16-19 mammalian subunits have been cloned and localized on different genes. Their assembly into proteins in a poorly defined stoichiometry forms the basis of functional and pharmacological GABA(A) receptor diversity, i.e. the receptor subtypes. The latter has been well documented in autoradiographic studies using ligands that label some of the receptors' various binding sites, corroborated by recombinant expression studies using the same tools. Significantly less heterogeneity has been found at the physiological level in native receptors, where the subunit combinations have been difficult to dissect. This review focuses on the characteristics, use and usefulness of various ligands and their binding sites to probe GABA(A) receptor properties and to gain insight into the biological function from fish to man and into evolutionary conserved GABA(A) receptor heterogeneity. We also summarize the properties of the novel mouse models created for the study of various brain functions and review the state-of-the-art imaging of brain GABA(A) receptors in various human neuropsychiatric conditions. The data indicate that the present ligands are only partly satisfactory tools and further ligands with subtype-selective properties are needed for imaging purposes and for confirming the behavioral and functional results of the studies presently carried out in gene-targeted mice with other species, including man.

  12. Expression of 5-HT2A receptors in prefrontal cortex pyramidal neurons projecting to nucleus accumbens. Potential relevance for atypical antipsychotic action.

    PubMed

    Mocci, Giuseppe; Jiménez-Sánchez, Laura; Adell, Albert; Cortés, Roser; Artigas, Francesc

    2014-04-01

    The prefrontal cortex (PFC) is involved in higher brain functions altered in schizophrenia. Classical antipsychotic drugs modulate information processing in cortico-limbic circuits via dopamine D2 receptor blockade in nucleus accumbens (NAc) whereas atypical antipsychotic drugs preferentially target cortical serotonin (5-HT) receptors. The brain networks involved in the therapeutic action of atypical drugs are not fully understood. Previous work indicated that medial PFC (mPFC) pyramidal neurons projecting to ventral tegmental area express 5-HT2A receptors suggesting that atypical antipsychotic drugs modulate dopaminergic activity distally, via 5-HT2A receptor (5-HT2A-R) blockade in PFC. Since the mPFC also projects heavily to NAc, we examined whether NAc-projecting pyramidal neurons also express 5-HT2A-R. Using a combination of retrograde tracing experiments and in situ hybridization we report that a substantial proportion of mPFC-NAc pyramidal neurons in rat brain express 5-HT2A-R mRNA in a layer- and area-specific manner (up to 68% in layer V of contralateral cingulate). The functional relevance of 5-HT2A-R to modulate mPFC-NAc projections was examined in dual-probe microdialysis experiments. The application of the preferential 5-HT2A-R agonist DOI into mPFC enhanced glutamate release locally (+66 ± 18%) and in NAc (+74 ± 12%) indicating that cortical 5-HT2A-R activation augments glutamatergic transmission in NAc. Since NAc integrates glutamatergic and dopaminergic inputs, blockade of 5-HT2A-R by atypical drugs may reduce cortical excitatory inputs onto GABAergic neurons of NAc, adding to dopamine D2 receptor blockade. Together with previous observations, the present results suggest that atypical antipsychotic drugs may control the activity of the mesolimbic pathway at cell body and terminal level.

  13. Structure, evolutionary conservation, and functions of angiotensin- and endothelin-converting enzymes.

    PubMed

    Macours, Nathalie; Poels, Jeroen; Hens, Korneel; Francis, Carmen; Huybrechts, Roger

    2004-01-01

    Angiotensin-converting enzyme, a member of the M2 metalloprotease family, and endothelin-converting enzyme, a member of the M13 family, are key components in the regulation of blood pressure and electrolyte balance in mammals. From this point of view, they serve as important drug targets. Recently, the involvement of these enzymes in the development of Alzheimer's disease was discovered. The existence of homologs of these enzymes in invertebrates indicates that these enzyme systems are highly conserved during evolution. Most invertebrates lack a closed circulatory system, which excludes the need for blood pressure regulators. Therefore, these organisms represent excellent targets for gaining new insights and revealing additional physiological roles of these important enzymes. This chapter reviews the structural and functional aspects of ACE and ECE and will particularly focus on these enzyme homologues in invertebrates.

  14. Endothelin-1 receptor antagonists in fetal development and pulmonary arterial hypertension.

    PubMed

    de Raaf, Michiel Alexander; Beekhuijzen, Manon; Guignabert, Christophe; Vonk Noordegraaf, Anton; Bogaard, Harm Jan

    2015-08-15

    The Pregnancy Prevention Program (PPP) is in place to prevent drug-induced developmental malformations. Remarkably, among the ten PPP-enlisted drugs are three endothelin-1 (ET-1) receptor antagonists (ERA's: ambrisentan, bosentan and macitentan), which are approved for the treatment of Pulmonary Arterial Hypertension (PAH). This review describes the effects of ERA's in PAH pathobiology and cardiopulmonary fetal development. While ERA's hamper pathological remodeling of the pulmonary vasculature and as such exert beneficial effects in PAH, they disturb fetal development of cardiopulmonary tissues. By blocking ET-1-mediated positive inotropic effects and myocardial fetal gene induction, ERA's may affect right ventricular adaptation to the increased pulmonary vascular resistance in both the fetus and the adult PAH patient.

  15. Autoradiographic localization of endothelin-1 binding sites in the cardiovascular and respiratory systems

    SciTech Connect

    Power, R.F.; Wharton, J.; Zhao, Y.; Bloom, S.R.; Polak, J.M.

    1989-01-01

    Specific high-affinity binding sites for endothelin-1 (ET-1) have been demonstrated in peripheral tissues using the technique of in vitro receptor autoradiography. Binding was time dependent and saturable and inhibited by coincubation with an excess of unlabeled ET-1 but resistant to dissociation. Binding sites were localized to blood vessels of all sizes including coronary arteries, intrapulmonary vessels, and intrarenal and intrasplenic arteries. In addition, high-affinity binding sites were identified on airway smooth muscle, over alveolar septa, and on nerve trunks. Scatchard analysis of the data revealed a Bmax of 250 amol/mm2 and a Kd of 0.1 nM for the binding of rat tracheal smooth muscle, with similar values for porcine coronary artery. The localization of binding sites is consistent with the known effects of ET-1 and suggests a direct action on specific receptors.

  16. High and low affinity binding sites for endothelin on cultured rat glomerular mesangial cells.

    PubMed

    Badr, K F; Munger, K A; Sugiura, M; Snajdar, R M; Schwartzberg, M; Inagami, T

    1989-06-15

    Endothelin contracts glomerular mesangial cells, thereby influencing glomerular size and filtration rate. Here, we demonstrate the presence of two ET-specific binding sites on cultured rat mesangial cells with Kds of 0.76 and 44.70 nM, and maximal binding capacity (Bmax) values of 6.78 x 10(2) and 27.60 x 10(2) binding sites/cell, respectively. Binding of [125I]-ET was maximal at 120 min at 4 degrees C, stable for the subsequent 60 min, and selective. No competition for binding was observed with greater than 1000-fold concentrations of atrial natriuretic peptide, angiotensin II, arginine vasopressin, nicardipine, or nifedipine. The presence of specific receptors for ET on glomerular mesangial cells suggests a major role for this peptide in the regulation of glomerular filtration rate.

  17. How does endothelial cell injury start? The role of endothelin in systemic sclerosis.

    PubMed

    Abraham, David; Distler, Oliver

    2007-01-01

    A considerable amount of research time has been invested in studies aimed at elucidating pathogenic processes in systemic sclerosis (SSc). Despite this, major challenges for biomedical science remain, such as identification of the key factors that determine susceptibility to SSc, and elucidation of the precise nature of the initiating event that causes endothelial cell injury and ultimately brings about the biological cascade(s) that lead to the pathologic vascular changes. Involved factors are likely to include genetic perturbations, environmental cues, tissue injury, infection and hypoxia/oxidative stress. As important as determining the initiating events are the identification and characterization of key factors that are functionally important in driving vascular disease progression, because these factors are potential targets for therapeutic intervention. This article reviews the role of endothelin as an example of a pleiotropic mediator with effects on various aspects of SSc pathogenesis, such as inflammation, vasculopathy and tissue remodelling.

  18. Behavioural evidence for a functional interaction between central 5-HT2 and 5-HT1A receptors.

    PubMed Central

    Backus, L. I.; Sharp, T.; Grahame-Smith, D. G.

    1990-01-01

    1. The possibility of 5-HT2 receptor modulation of central 5-HT1A receptor function has been examined using the 5-hydroxytryptamine (5-HT) behavioural syndrome induced by 5-HT1A receptor active drugs in rats. 2. The 5-HT2/5-HTIC antagonist ritanserin (0.1-2 mg kg-1) increased the 5-HT behavioural syndrome induced by submaximally effective doses of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) and gepirone. 3. Pretreatment with the 5-HT2/5-HT1C antagonist ICI 170,809 (0.25-5 mg kg-1) also enhanced the behavioural syndrome induced by 8-OH-DPAT or 5-MeODMT. 4. The 5-HT2/alpha 1-adrenoceptor antagonist ketanserin in a low dose (0.25 mg kg-1) significantly increased the 5-HT behavioural syndrome induced by 8-OH-DPAT or 5-MeODMT, while in a higher dose (2.5 mg kg-1) this drug decreased the response. Experiments with prazosin indicate that the higher dose of ketanserin might reduce the 5-HT behavioural syndrome through blockade of alpha 1-adrenoceptors. 5. Ritanserin and ICI 170,809 had no effect on apomorphine-induced stereotypy or hyperactivity, indicating that these drugs do not produce non-specific behavioural activation. 6. Ritanserin and ICI 170,809 inhibited quipazine-induced wet dog shakes at doses similar to those enhancing the 5-HT behavioural syndrome. 7. We suggest that ritanserin, ICI 170,809 and ketanserin enhance 5-HT1A agonist-induced behaviour through blockade of an inhibitory 5-HT2 receptor regulating or coupled to 5-HT1A receptor-mediated function. PMID:2145051

  19. Functional and Molecular Characterization of the Endothelin System in Retinal Arterioles

    PubMed Central

    Hein, Travis W.; Ren, Yi; Yuan, Zhaoxu; Xu, Wenjuan; Somvanshi, Sonal; Nagaoka, Taiji; Yoshida, Akitoshi; Kuo, Lih

    2009-01-01

    Purpose Activation of the endothelin (ET) system has been implicated in the pathogenesis of retinal ischemic disease. Although ET-1, the predominant endogenous isoform of ET, has been shown to cause constriction of retinal vessels, the expression and functional significance of its synthesis and the involved specific ET receptors in retinal arterioles remain unknown. The authors examined the roles of ETA and ETB receptors and of endothelin-converting enzyme (ECE)-1 in ET-1–induced vasomotor responses of single retinal arterioles. Methods To exclude systemic confounding effects, porcine retinal arterioles were isolated for vasoreactivity and molecular studies. Results Isolated and pressurized retinal arterioles developed basal tone and constricted in a manner dependent on concentration to ET-1. ET-1 precursor big ET-1 elicited time-dependent vasoconstriction over 20 minutes, which was blocked by the ECE-1 inhibitor phosphoramidon. ETA receptor antagonist BQ123 inhibited most (approximately 90%) of vasoconstrictions to ET-1 and big ET-1. ETB receptor agonist sarafotoxin also elicited concentration-dependent constriction of retinal arterioles but with significantly less potency than ET-1. ETB receptor antagonist BQ788 abolished vasoconstriction to sarafotoxin but only slightly reduced responses to ET-1 and big ET-1. Protein and mRNA expressions of ETA, ETB, and ECE-1 were detected in retinal arterioles. Immunohistochemistry revealed ETA and ETB receptors predominantly in smooth muscle and ECE-1 predominantly in endothelium and smooth muscle. Conclusions ET-1 elicits constriction of retinal arterioles predominantly through the activation of smooth muscle ETA receptors. Endogenous production of ET-1 from vascular ECE-1 is sufficient to evoke ETA receptor–dependent constriction in retinal arterioles. PMID:19151386

  20. Modulatory effect of endothelin-1 and -3 on neuronal norepinephrine release in the rat posterior hypothalamus.

    PubMed

    Di Nunzio, Andrea S; Legaz, Guillermina; Rodano, Valeria; Bianciotti, Liliana G; Vatta, Marcelo S

    2004-04-15

    Based upon the existence of high density of ET-receptors on catecholaminergic neurons of the hypothalamus, we studied the effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) on neuronal norepinephrine (NE) release in the rat posterior hypothalamus. The intracellular pathways and receptors involved were also investigated. Neuronal NE release was enhanced by ET-1 and ET-3 (10 etaM). The selective antagonists of subtype A and B ET receptors (ETA, ETB) (100 etaM BQ-610 and 100 etaM BQ-788, respectively) abolished the increase induced by ET-1 but not by ET-3. The PLC inhibitor, U73122 (10 microM), abolished ET-1 and ET-3 response. GF-109203X (100 etaM) (PKC inhibitor) blocked the increase in NE release produced by ET-3 and partially blocked ET-1 response. The inositol 1,4,5-trisphosphate-induced calcium release inhibitor, 42 microM 2-APB, inhibited the stimulatory effect induced by ET-3 but not by ET-1. The PKA inhibitor, 500 etaM H-89, blocked the increase in neuronal NE release evoked by ET-1 but not by ET-3. Our results showed that ET-1 as well as ET-3 displayed an excitatory neuromodulatory effect on neuronal NE release in the rat posterior hypothalamus. ET-1 through an atypical ETA or ETB receptor activated the PLC/PKC signalling pathway as well as the cAMP pathway, whereas ET-3 through a non-ETA/non-ETB receptor activated the phosphoinositide pathway. Both ETs would enhance the sympathoexcitatory response elicited by the posterior hypothalamus and thus participate in cardiovascular regulation.

  1. Smooth Muscle Endothelin B Receptors Regulate Blood Pressure but Not Vascular Function or Neointimal Remodeling

    PubMed Central

    Miller, Eileen; Czopek, Alicja; Duthie, Karolina M.; Kirkby, Nicholas S.; van de Putte, Elisabeth E. Fransen; Christen, Sibylle; Kimmitt, Robert A.; Moorhouse, Rebecca; Castellan, Raphael F.P.; Kotelevtsev, Yuri V.; Kuc, Rhoda E.; Davenport, Anthony P.; Dhaun, Neeraj; Webb, David J.

    2017-01-01

    The role of smooth muscle endothelinB (ETB) receptors in regulating vascular function, blood pressure (BP), and neointimal remodeling has not been established. Selective knockout mice were generated to address the hypothesis that loss of smooth muscle ETB receptors would reduce BP, alter vascular contractility, and inhibit neointimal remodeling. ETB receptors were selectively deleted from smooth muscle by crossing floxed ETB mice with those expressing cre-recombinase controlled by the transgelin promoter. Functional consequences of ETB deletion were assessed using myography. BP was measured by telemetry, and neointimal lesion formation induced by femoral artery injury. Lesion size and composition (day 28) were analyzed using optical projection tomography, histology, and immunohistochemistry. Selective deletion of ETB was confirmed by genotyping, autoradiography, polymerase chain reaction, and immunohistochemistry. ETB-mediated contraction was reduced in trachea, but abolished from mesenteric veins, of knockout mice. Induction of ETB-mediated contraction in mesenteric arteries was also abolished in these mice. Femoral artery function was unaltered, and baseline BP modestly elevated in smooth muscle ETB knockout compared with controls (+4.2±0.2 mm Hg; P<0.0001), but salt-induced and ETB blockade–mediated hypertension were unaltered. Circulating endothelin-1 was not altered in knockout mice. ETB-mediated contraction was not induced in femoral arteries by incubation in culture medium or lesion formation, and lesion size was not altered in smooth muscle ETB knockout mice. In the absence of other pathology, ETB receptors in vascular smooth muscle make a small but significant contribution to ETB-dependent regulation of BP. These ETB receptors have no effect on vascular contraction or neointimal remodeling. PMID:28028193

  2. Flavonol-rich dark cocoa significantly decreases plasma endothelin-1 and improves cognition in urban children.

    PubMed

    Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Cross, Janet V; Engle, Randall; Aragón-Flores, Mariana; Gómez-Garza, Gilberto; Jewells, Valerie; Medina-Cortina, Humberto; Solorio, Edelmira; Chao, Chih-Kai; Zhu, Hongtu; Mukherjee, Partha S; Ferreira-Azevedo, Lara; Torres-Jardón, Ricardo; D'Angiulli, Amedeo

    2013-01-01

    Air pollution exposures are linked to systemic inflammation, cardiovascular and respiratory morbidity and mortality, neuroinflammation and neuropathology in young urbanites. In particular, most Mexico City Metropolitan Area (MCMA) children exhibit subtle cognitive deficits, and neuropathology studies show 40% of them exhibiting frontal tau hyperphosphorylation and 51% amyloid-β diffuse plaques (compared to 0% in low pollution control children). We assessed whether a short cocoa intervention can be effective in decreasing plasma endothelin 1 (ET-1) and/or inflammatory mediators in MCMA children. Thirty gram of dark cocoa with 680 mg of total flavonols were given daily for 10.11 ± 3.4 days (range 9-24 days) to 18 children (10.55 years, SD = 1.45; 11F/7M). Key metabolite ratios in frontal white matter and in hippocampus pre and during cocoa intervention were quantified by magnetic resonance spectroscopy. ET-1 significantly decreased after cocoa treatment (p = 0.0002). Fifteen children (83%) showed a marginally significant individual improvement in one or both of the applied simple short memory tasks. Endothelial dysfunction is a key feature of exposure to particulate matter (PM) and decreased endothelin-1 bioavailability is likely useful for brain function in the context of air pollution. Our findings suggest that cocoa interventions may be critical for early implementation of neuroprotection of highly exposed urban children. Multi-domain nutraceutical interventions could limit the risk for endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, cognitive deficits, structural volumetric detrimental brain effects, and the early development of the neuropathological hallmarks of Alzheimer's and Parkinson's diseases.

  3. Flavonol-rich dark cocoa significantly decreases plasma endothelin-1 and improves cognition in urban children

    PubMed Central

    Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Cross, Janet V.; Engle, Randall; Aragón-Flores, Mariana; Gómez-Garza, Gilberto; Jewells, Valerie; Weili, Lin; Medina-Cortina, Humberto; Solorio, Edelmira; Chao, Chih-kai; Zhu, Hongtu; Mukherjee, Partha S.; Ferreira-Azevedo, Lara; Torres-Jardón, Ricardo; D'Angiulli, Amedeo

    2013-01-01

    Air pollution exposures are linked to systemic inflammation, cardiovascular and respiratory morbidity and mortality, neuroinflammation and neuropathology in young urbanites. In particular, most Mexico City Metropolitan Area (MCMA) children exhibit subtle cognitive deficits, and neuropathology studies show 40% of them exhibiting frontal tau hyperphosphorylation and 51% amyloid-β diffuse plaques (compared to 0% in low pollution control children). We assessed whether a short cocoa intervention can be effective in decreasing plasma endothelin 1 (ET-1) and/or inflammatory mediators in MCMA children. Thirty gram of dark cocoa with 680 mg of total flavonols were given daily for 10.11 ± 3.4 days (range 9–24 days) to 18 children (10.55 years, SD = 1.45; 11F/7M). Key metabolite ratios in frontal white matter and in hippocampus pre and during cocoa intervention were quantified by magnetic resonance spectroscopy. ET-1 significantly decreased after cocoa treatment (p = 0.0002). Fifteen children (83%) showed a marginally significant individual improvement in one or both of the applied simple short memory tasks. Endothelial dysfunction is a key feature of exposure to particulate matter (PM) and decreased endothelin-1 bioavailability is likely useful for brain function in the context of air pollution. Our findings suggest that cocoa interventions may be critical for early implementation of neuroprotection of highly exposed urban children. Multi-domain nutraceutical interventions could limit the risk for endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, cognitive deficits, structural volumetric detrimental brain effects, and the early development of the neuropathological hallmarks of Alzheimer's and Parkinson's diseases. PMID:23986703

  4. Effect of mineralocorticoid treatment in mice with collecting duct-specific knockout of endothelin-1.

    PubMed

    Lynch, I Jeanette; Welch, Amanda K; Gumz, Michelle L; Kohan, Donald E; Cain, Brian D; Wingo, Charles S

    2015-12-15

    Aldosterone increases blood pressure (BP) by stimulating sodium (Na) reabsorption within the distal nephron and collecting duct (CD). Aldosterone also stimulates endothelin-1 (ET-1) production that acts within the CD to inhibit Na reabsorption via a negative feedback mechanism. We tested the hypothesis that this renal aldosterone-endothelin feedback system regulates electrolyte balance and BP by comparing the effect of a high-salt (NaCl) diet and mineralocorticoid stimulation in control and CD-specific ET-1 knockout (CD ET-1 KO) mice. Metabolic balance and radiotelemetric BP were measured before and after treatment with desoxycorticosterone pivalate (DOCP) in mice fed a high-salt diet with saline to drink. CD ET-1 KO mice consumed more high-salt diet and saline and had greater urine output than controls. CD ET-1 KO mice exhibited increased BP and greater fluid retention and body weight than controls on a high-salt diet. DOCP with high-salt feeding further increased BP in CD ET-1 KO mice, and by the end of the study the CD ET-1 KO mice were substantially hypernatremic. Unlike controls, CD ET-1 KO mice failed to respond acutely or escape from DOCP treatment. We conclude that local ET-1 production in the CD is required for the appropriate renal response to Na loading and that lack of local ET-1 results in abnormal fluid and electrolyte handling when challenged with a high-salt diet and with DOCP treatment. Additionally, local ET-1 production is necessary, under these experimental conditions, for renal compensation to and escape from the chronic effects of mineralocorticoids.

  5. Regulation of endothelin-converting enzyme-1 (ECE-1) by the calcimimetic R-568.

    PubMed

    Martínez-Miguel, Patricia; Medrano-Andrés, Diana; Lopes-Martín, Vanessa; Arribas-Gómez, Ignacio; Rodríguez-Puyol, Manuel; Rodríguez-Puyol, Diego; López-Ongil, Susana

    2013-10-01

    Although calcimimetics were developed to block parathyroid hormone synthesis, some reports suggest that they may also reduce blood pressure by unknown mechanisms. Calcimimetic-induced changes in the synthesis of endothelial vasoactive factors could be involved. Wistar rats were treated with the calcimimetic R-568, and systolic blood pressure (SBP) was registered with a tail-cuff sphygmomanometer, the content of endothelial nitric oxide synthase (eNOS) and endothelin-converting enzyme (ECE-1) in tissue was evaluated by immunohistochemistry and Western blot, circulating levels of endothelin-1 (ET-1) were measured by ELISA. R-568 reduced SBP and circulating levels of ET-1, without changes in eNOS expression. In contrast, R-568 increased the lung and vascular content of ECE-1. In order to analyze the mechanisms involved, we studied the effect of R-568 on human endothelial cells. R-568 did not modify neither eNOS protein content nor pre-pro-ET-1 mRNA expression, but increased ECE-1 protein content, and decreased ET-1 synthesis and ECE-1 activity. The inhibition of ECE-1 activity was very strong, similar to the classic ECE inhibitor phosphoramidon, the addition of exogenous zinc restored enzymatic activity. Moreover, the amount of zinc in immunoprecipitated ECE from R-568 treated cells was 3-fold less than in control cells. In conclusion, R-568 inhibits ECE by expelling zinc from the enzyme, with the subsequent decrease in enzymatic activity and reducing circulating levels of ET-1, which may be responsible for the lower SBP observed in R-568-treated rats. This descent would be partially compensated by the increased synthesis of the ECE-1 itself, and by other homeostatic mechanisms that regulate SBP.

  6. Down-regulation of endothelin receptors in the ventrolateral medulla of spontaneously hypertensive rats

    SciTech Connect

    Gulati, A.; Rebello, S. )

    1991-01-01

    The binding of ({sup 125}I) sarafotoxin 6b (SRT 6b) and ({sup 125}I) endothelin-1 (ET-1) to endothelin (ET) receptors of neuronal membranes prepared from cerebral cortex and ventrolateral medulla of 8 week old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats was determined. ({sup 125}I) SRT 6b bound to the membranes of cerebral cortex and ventrolateral medulla at a single high affinity site. The binding of ({sup 125}I) SRT 6b in the cerebral cortex was found to be similar in SHR and WKY rats. However, in the ventrolateral medulla ({sup 125}I) SRT 6b binding was found to be significantly lower in SHR as compared to WKY rats. The decreased binding was due to decrease (48%) in the B{sub max} values in SHR rats as compared to WKY rats. The K{sub d} values were similar in SHR and WKY rats. ({sup 125}I) ET-1 also bound to the membranes of cerebral cortex and ventrolateral medulla at a single high affinity site. The binding of ({sup 125}I) ET-1 in the cerebral cortex was found to be similar in SHR and WKY rats. However, in the ventrolateral medulla ({sup 125}I) ET-1 binding was found to be significantly lower in SHR as compared to WKY rats. The decreased binding was due to 36% decrease in the B{sub max} values in SHR rats as compared to WKY rats. The K{sub d} values were similar in SHR and WKY rats. It is concluded that the population of ET receptors is less in the ventrolateral medulla of SHR rats and may be contributing to the regulation of blood pressure.

  7. Endogenous endothelin-1and femoral artery shear rate: impact of age and implications for atherosclerosis

    PubMed Central

    Trinity, Joel D.; Barrett-O’Keefe, Zachary; Ives, Stephen J.; Morgan, Garrett; Rossman, Matthew J.; Donato, Anthony J.; Runnels, Sean; Morgan, David E.; Gmelch, Benjamin S.; Bledsoe, Amber D.; Richardson, Russell S.; Wray, D. Walter

    2017-01-01

    Background Both altered shear rate and endothelin-1 (ET-1) are associated with the age-related development of atherosclerosis. However, the role of ET-1, a potent endogenous vasoconstrictor, in altering shear rate in humans, especially in the atherosclerotic-prone vasculature of the leg, is unknown. Therefore, this study examined the contribution of ET-1 to the age-related alterations in common femoral artery (CFA) shear rate. Method BQ-123, a specific endothelin type A (ETA) receptor antagonist, was infused into the CFA, and diameter and blood velocity were measured by Doppler ultrasound in young (n = 8, 24 ± 2 years) and old (n = 9, 70 ± 2 years) study participants. Results and conclusion The old had greater intima–media thickening in the CFA, indicative of a preatherogenic phenotype. Prior to infusion, the old study participants exhibited reduced mean shear rate (27 ± 3/s) compared with the young study participants (62 ± 9/s). This difference was likely driven by attenuated antegrade shear rate in the old as retrograde shear rate was similar in the young and old. Inhibition of ETA receptors, by BQ-123, increased leg blood flow in the old, but not in the young, abolishing age-related differences. Older study participants had a larger CFA (young: 0.82 ± 0.03 cm, old: 0.99 ± 0.03 cm) in which BQ-123 induced significant vasodilation (5.1 ± 1.0%), but had no such effect in the young (−0.8 ± 0.8%). Interestingly, despite the age-specific, BQ-123-induced increase in leg blood flow and CFA diameter, shear rate patterns remained largely unchanged. Therefore, ET-1, acting through the ETA receptors, exerts a powerful age-specific vasoconstriction. However, removal of this vasoconstrictor stimulus does not augment mean shear rate in the old. PMID:26599223

  8. Prognostic Significance of Active and Modified forms of Endothelin 1 in Patients with Heart Failure with Reduced Ejection Fraction

    PubMed Central

    Gottlieb, Stephen S.; Harris, Kristie; Todd, John; Estis, Joel; Christenson, Robert H.; Torres, Victoria; Whittaker, Kerry; Rebuck, Heather; Wawrzyniak, Andrew; Krantz, David S.

    2015-01-01

    Objectives Concentrations of endothelin I (ET1) are elevated in CHF patients, and, like other biomarkers that reflect hemodynamic status and cardiac pathophysiology, are prognostic. The Singulex assay (Sgx-ET1) measures the active form of ET1, with a short in-vivo half-life and C-terminal endothelin-1 (CT-ET1) is measured by the Brahms assay and is a modified (degraded) product with longer half-life. We aimed to determine the prognostic importance of active and modified forms of endothelin 1 (Singulex and Brahms assays) in comparison with other commonly measured biomarkers of inflammation, hemodynamic status and cardiac physiology in CHF. Design & Methods Plasma biomarkers (Sgx-ET1, CT-ET1, NTproBNP, IL-6, TNFα, cTnI, VEGF, hs-CRP, Galectin-3, ST2) were measured in 134 NYHA class II and III CHF patients with systolic dysfunction. Prognostic importance of biomarkers for hospitalization or death were calculated by both logistic regression and Kaplan-Meier survival analyses. Results CT-ET1 (OR 5.2, 95% CI 1.7–15.7) and Sgx-ET1 (OR 2.9, CI 1.1–7.7) were independent predictors of hospitalization and death and additively predicted events after adjusting for age, sex and other significant biomarkers. Other biomarkers did not improve the model. Similarly, in Cox regression analysis, only CT-ET1 (HR 3.4, 95% CI 1.4–8.4), VEGF (2.7, 95% CI 1.3–5.4) and Sgx-ET1 (HR 2.6, 95% CI 1.2–5.6) were independently prognostic. Conclusions Elevated concentrations of endothelin 1 predict mortality and hospitalizations in HF patients. Endothelin 1 was more prognostic than commonly obtained hemodynamic, inflammatory and fibrotic biomarkers. Two different assays of endothelin 1 independently and synergistically were prognostic, suggesting either complementary information or extreme prognostic importance. PMID:25541019

  9. [The hemodynamic effect of thoracic sympathetic ganglion blockade in the anesthetized adult mongrel dogs].

    PubMed

    Yamagami, H

    1994-03-01

    Hemodynamic alterations with the thoracic sympathetic ganglion blockade were elucidated in the anesthetized open-chest dogs, under controlled ventilation with 100% oxygen and receiving fentanyl, pentobarbital and pancuronium administration, and the effect of blockade was assessed by increase in skin-surface temperature at the specific regions of the upper extremity. All dogs with thoracic sympathetic ganglion blockade revealed the increased skin temperature in blocked extremities and decreased skin temperature in the contralateral side with simultaneous compensatory vasoconstriction ("Borrowing-Lending phenomenon"). Four groups were classified according to the side and range of blockade: A-group (right Th7.8 ganglion, N = 17), B-group (left-Th7.8 ganglion, N = 8), C-group (right Th2.3 ganglion, N = 13) and D-group (left-Th2.3 ganglion, N = 10). The hemodynamic variables after the middle thoracic sympathetic ganglion blockade showed no remarkable changes but heart-rate, mean arterial blood pressure and cardiac output decreased significantly with the upper right-side thoracic sympathetic ganglion blockade, and the inhibited circulatory state lasted twenty minutes after blockade. No significant skin temperature changes were observed after blockade among four groups. The results suggest that the patient after upper thoracic sympathetic ganglion blockade should be cared with these circulatory changes in mind.

  10. The Naval Blockade: A Study of Factors Necessary for Effective Utilization

    DTIC Science & Technology

    1987-06-05

    PERU AND BOLIVIA BY CHILE 1879-1884 THE SPANISH AMERICAN WAR 1898 , . THE DECLARATION OF LONDON 1909 WORLD WAR I: THE BRITISH BLOCKADE OF...operations ashore can have on the blockade at sea. THE BLOCKADE DP PERU AND BOLIVIA BY CHILE 1B79-1S84 Beginning in 1379, Chile used a vastly superior...fleet to blockade the coasts of Peru and Bolivia . This Chilean Fleet had two British built battleships, giving it sea power greatly superior to that

  11. Blood flow, sympathetic activity and pain relief following lumbar sympathetic blockade or surgical sympathectomy.

    PubMed

    Walsh, J A; Glynn, C J; Cousins, M J; Basedow, R W

    1985-02-01

    The physiological effects of local anaesthetic (bupivacaine), neurolytic (phenol) blockade and surgical ablation of the lumbar sympathetic chain were assessed in patients with peripheral vascular disease or sympathetic dystrophy. Local anaesthetic blockade in 49 patients resulted in significant decrease in pain, plantar sweating and in the vasoconstrictor ice response of the foot, as well as a significant increase in skin temperature and foot blood flow. Subsequent neurolytic blockade in 31 of these patients achieved an effective denervation as assessed by the same physiological measurements. The magnitude of changes in blood flow and sympathetic activity were similar for local anaesthetic and neurolytic blockade as well as in six patients who underwent surgical sympathectomy.

  12. VEGF blockade inhibits angiogenesis and reepithelialization of endometrium

    PubMed Central

    Fan, Xiujun; Krieg, Sacha; Kuo, Calvin J.; Wiegand, Stanley J.; Rabinovitch, Marlene; Druzin, Maurice L.; Brenner, Robert M.; Giudice, Linda C.; Nayak, Nihar R.

    2008-01-01

    Despite extensive literature on vascular endothelial growth factor (VEGF) expression and regulation by steroid hormones, the lack of clear understanding of the mechanisms of angiogenesis in the endometrium is a major limitation for use of antiangiogenic therapy targeting endometrial vessels. In the current work, we used the rhesus macaque as a primate model and the decidualized mouse uterus as a murine model to examine angiogenesis during endometrial breakdown and regeneration. We found that blockade of VEGF action with VEGF Trap, a potent VEGF blocker, completely inhibited neovascularization during endometrial regeneration in both models but had no marked effect on preexisting or newly formed vessels, suggesting that VEGF is essential for neoangiogenesis but not survival of mature vessels in this vascular bed. Blockade of VEGF also blocked reepithelialization in both the postmenstrual endometrium and the mouse uterus after decidual breakdown, evidence that VEGF has pleiotropic effects in the endometrium. In vitro studies with a scratch wound assay showed that the migration of luminal epithelial cells during repair involved signaling through VEGF receptor 2–neuropilin 1 (VEGFR2-NP1) receptors on endometrial stromal cells. The leading front of tissue growth during endometrial repair was strongly hypoxic, and this hypoxia was the local stimulus for VEGF expression and angiogenesis in this tissue. In summary, we provide novel experimental data indicating that VEGF is essential for endometrial neoangiogenesis during postmenstrual/postpartum repair.—Fan, X., Krieg, S., Kuo, C. J., Wiegand, S. J., Rabinovitch, M., Druzin, M. L., Brenner, R. M., Giudice, L. C., Nayak, N. R. VEGF blockade inhibits angiogenesis and reepithelialization of endometrium. PMID:18606863

  13. Role of serotonin 5-HT2A receptors in the development of cardiac hypertrophy in response to aortic constriction in mice.

    PubMed

    Lairez, O; Cognet, T; Schaak, S; Calise, D; Guilbeau-Frugier, C; Parini, A; Mialet-Perez, J

    2013-06-01

    Serotonin, in addition to its fundamental role as a neurotransmitter, plays a critical role in the cardiovascular system, where it is thought to be involved in the development of cardiac hypertrophy and failure. Indeed, we recently found that mice with deletion of monoamine oxidase A had enhanced levels of blood and cardiac 5-HT, which contributed to exacerbation of hypertrophy in a model of experimental pressure overload. 5-HT2A receptors are expressed in the heart and mediate a hypertrophic response to 5-HT in cardiac cells. However, their role in cardiac remodeling in vivo and the signaling pathways associated are not well understood. In the present study, we evaluated the effect of a selective 5-HT2A receptor antagonist, M100907, on the development of cardiac hypertrophy induced by transverse aortic constriction (TAC). Cardiac 5-HT2A receptor expression was transiently increased after TAC, and was recapitulated in cardiomyocytes, as observed with 5-HT2A in situ labeling by immunohistochemistry. Selective blockade of 5-HT2A receptors prevented the development of cardiac hypertrophy, as measured by echocardiography, cardiomyocyte area and heart weight-to-body weight ratio. Interestingly, activation of calmodulin kinase (CamKII), which is a core mechanism in cardiac hypertrophy, was reduced in cardiac samples from M100907-treated TAC mice compared to vehicle-treated mice. In addition, phosphorylation of histone deacetylase 4 (HDAC4), a downstream partner of CamKII was significantly diminished in M100907-treated TAC mice. Thus, our results show that selective blockade of 5-HT2A receptors has beneficial effect in the development of cardiac hypertrophy through inhibition of the CamKII/HDAC4 pathway.

  14. Quantum confinement and Coulomb blockade in isolated nanodiamond crystallites

    NASA Astrophysics Data System (ADS)

    Bolker, Asaf; Saguy, Cecile; Tordjman, Moshe; Kalish, Rafi

    2013-07-01

    We present direct experimental evidence of quantum confinement effects in single isolated nanodiamonds by scanning tunneling spectroscopy. For grains smaller than 4.5 nm, the band gap was found to increase with decreasing nanodiamond size and a well-defined, evenly spaced, 12-peak structure was observed on the conduction band side of the conductance curves. We attribute these peaks to the Coulomb blockade effect, reflecting the 12-fold degeneracy of the first electron-energy level in the confined nanodiamond. The present results shed light on the size dependence of the electronic properties of single nanodiamonds and are of major importance for future nanodiamond-based applications.

  15. Classical Coulomb blockade of a silicon nanowire dot

    NASA Astrophysics Data System (ADS)

    Huang, Shaoyun; Fukata, Naoki; Shimizu, Maki; Yamaguchi, Tomohiro; Sekiguchi, Takashi; Ishibashi, Koji

    2008-05-01

    Single electron transistors (SETs) have been fabricated with an individual n-type single-crystal silicon nanowire (SiNW) that was grown by a catalytic chemical vapor deposition technique, and their transport properties have been measured in low temperatures. The SiNW-SET in the present work exhibited well pronounced Coulomb oscillations in a wide gate voltage range from -10to10V, featuring in uniform peak height, uniform full width at half maximum, and equidistant peak spacing. The charging energy turned out to be 64μeV. The temperature dependence of Coulomb oscillations revealed that the dot worked within the classical Coulomb blockade model.

  16. 5-HT2A receptor activation is necessary for CO2-induced arousal

    PubMed Central

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

    2015-01-01

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

  17. GABA-A receptors regulate neocortical neuronal migration in vitro and in vivo.

    PubMed

    Heck, Nicolas; Kilb, Werner; Reiprich, Petra; Kubota, Hisahiko; Furukawa, Tomonori; Fukuda, Atsuo; Luhmann, Heiko J

    2007-01-01

    The cortical migration process depends on a number of trophic factors and on the activation of different voltage- and ligand-gated channels. We investigated the role of gamma-aminobutyric acid (GABA) type A receptors in the neuronal migration process of the newborn rat parietal cortex in vivo and in vitro. Local in vivo application of the GABA-A antagonist bicuculline methiodide (BMI) or the agonist muscimol via cortical surface Elvax implants induced prominent alterations in the cortical architecture when compared with untreated or sham-operated controls. BMI- and muscimol-treated animals revealed heterotopic cell clusters in the upper layers and a complete loss of the cortical lamination in the region underlying the Elvax implant. Immunocytochemical staining for glial fibrillary acidic protein, N-methyl-D-aspartate receptors, and GABA demonstrated that heterotopia was not provoked by glial proliferation and confirmed the presence of both glutamatergic and GABAergic neurons. In organotypic neocortical slices from embryonic day 18-19 embryos, application of BMI and to a lesser extent also muscimol induced an increase in the migration speed and an accumulation of neurons in the upper cortical layers. Spontaneous intracellular calcium ([Ca2+]i) oscillations in neocortical slices from newborn rats were abolished by BMI (5 and 20 microM) and muscimol (1 and 10 microM), indicating that both compounds interfere with [Ca2+]i signaling required for normal neuronal migration. Electrophysiological recordings from migrating neurons in newborn rat neocortical slices indicate that long-term application of muscimol causes a pronounced reduction (1 microM muscimol) or blockade (10 microM) in the responsiveness of postsynaptic GABA-A receptors due to a pronounced receptor desensitization. Our results indicate that modulation of GABA-A receptors by compounds acting as agonists or antagonists may profoundly influence the neuronal migration process in the developing cerebral cortex.

  18. 5-HT2A receptors are involved in cognitive but not antidepressant effects of fluoxetine.

    PubMed

    Castañé, Anna; Kargieman, Lucila; Celada, Pau; Bortolozzi, Analía; Artigas, Francesc

    2015-08-01

    The prefrontal cortex (PFC) plays a crucial role in cognitive and affective functions. It contains a rich serotonergic (serotonin, 5-HT) innervation and a high density of 5-HT receptors. Endogenous 5-HT exerts robust actions on the activity of pyramidal neurons in medial PFC (mPFC) via excitatory 5-HT2A and inhibitory 5-HT1A receptors, suggesting the involvement of 5-HT neurotransmission in cortical functions. However, the underlying mechanisms must be elucidated. Here we examine the role of 5-HT2A receptors in the processing of emotional and cognitive signals evoked by increasing the 5-HT tone after acute blockade of the 5-HT transporter. Fluoxetine (5-20mg/kg i.p.) dose-dependently reduced the immobility time in the tail-suspension test in wild-type (WT) and 5-HT2Aknockout (KO2A) mice, with non-significant differences between genotypes. Fluoxetine (10mg/kg i.p.) significantly impaired mice performance in the novel object recognition test 24h post-administration in WT, but not in KO2A mice. The comparable effect of fluoxetine on extracellular 5-HT in the mPFC of both genotypes suggests that presynaptic differences are not accountable. In contrast, single unit recordings of mPFC putative pyramidal neurons showed that fluoxetine (1.8-7.2mg/kg i.v.) significantly increased neuronal discharge in KO2A but not in WT mice. This effect is possibly mediated by an altered excitatory/inhibitory balance in the PFC in KO2A mice. Overall, the present results suggest that 5-HT2A receptors play a detrimental role in long-term memory deficits mediated by an excess 5-HT in PFC.

  19. Clinical/pharmacological aspect of adenosine A2A receptor antagonist for dyskinesia.

    PubMed

    Kanda, Tomoyuki; Uchida, Shin-ichi

    2014-01-01

    Dopamine replacement therapy using the dopamine precursor, l-3,4-dihydroxyphenylalanine (l-DOPA), with a peripheral dopa decarboxylase inhibitor is the most effective treatment currently available for the symptoms of Parkinson's disease (PD). However, the long-term use of dopaminergic therapies for PD is often limited by the development of motor response complications, such as dyskinesia. Adenosine A2A receptors are a promising nondopaminergic target for the treatment of PD. The treatment of motor response complications involves combinations of regular and controlled release L-DOPA, perhaps with the addition of a COMT inhibitor or the use of a longer-acting dopamine agonist. However, when dyskinesia is already established, the increase in dopaminergic load produced by the addition of a dopamine agonist can result in an increase in the severity and duration of dyskinesia. Currently, there are no well-tolerated antidyskinesia agents available. Amantadine, which may exert its effects through the inhibition of N-methyl-D-aspartate (NMDA) receptors, shows some effects on established dyskinesia. Dyskinesia has a negative impact on the quality of life of patients, sometimes being more disabling than PD itself. Although some patients prefer experiencing dyskinesia than being in the OFF state and unable to move, alternative, more effective therapies are still required for severe disabling dyskinesia to afford patients an improved quality of life while in the ON state. The mechanisms causing and maintaining the dyskinesia have not been clarified. The application of a nondopaminergic approach to modify the basal ganglial activity would be helpful to better understand and treat dyskinesia. The use of an adenosine A2A receptor may provide one such approach. In this literature review, we will summarize the current knowledge from both clinical and nonclinical studies on the effects of adenosine A2A receptor blockade on dyskinesia.

  20. The serotonin 5-Hydroxytryptaphan1A receptor agonist, (+)8-hydroxy-2-(di-n-propylamino)-tetralin, stimulates sympathetic-dependent increases in venous tone during hypovolemic shock.

    PubMed

    Tiniakov, Ruslan; Scrogin, Karie E

    2006-11-01

    Adjuvant treatment of hypovolemic shock with vasoconstrictors is controversial due to their propensity to raise arterial resistance and exacerbate ischemia. A more advantageous therapeutic approach would use agents that also promote venoconstriction to augment perfusion pressure through increased venous return. Recent studies indicate that 5-hydroxytryptophan (5-HT)(1A) receptor agonists increase blood pressure by stimulating sympathetic drive when administered after acute hypotensive hemorrhage. Given that venous tone is highly dependent upon sympathetic activation of alpha(2)-adrenergic receptors, we hypothesized that the 5-HT(1A) receptor agonist, (+)8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), would increase venous tone in rats subject to hypovolemic shock through sympathetic activation of alpha(2)-adrenergic receptors. Systemic administration of 8-OH-DPAT produced a sustained rise in blood pressure (+44 +/- 3 mm Hg 35 min after injection, P < 0.01 versus saline) and mean circulatory filling pressure (+4.2 +/- 0.7 mm Hg, P < 0.01 versus saline) in conscious rats subjected to hypovolemic shock. An equipressor infusion of epinephrine failed to influence mean circulatory filling pressure (MCFP). Ganglionic blockade, alpha(1)-, or peripheral alpha(2)-adrenergic receptor blockade prevented the rise in MCFP observed with 8-OH-DPAT, but only alpha(1)-adrenergic receptor blockade diminished the pressor effect of the drug (P < 0.01). 8-OH-DPAT raises blood pressure in rats in hypovolemic shock through both direct vascular activation and sympathetic activation of alpha(1)-adrenergic receptors. The sympathoexcitatory effect of 8-OH-DPAT contributes to elevated venous tone through concurrent activation of both alpha(1)- and alpha(2)-adrenergic receptors. The data suggest that 5-HT(1A) receptor agonists may provide an advantageous alternative to currently therapeutic interventions used to raise perfusion pressure in hypovolemic shock.

  1. Endothelin-1 down-regulates matrix metalloproteinase 14 and 15 expression in human first trimester trophoblasts via endothelin receptor type B

    PubMed Central

    Majali-Martinez, Alejandro; Velicky, Philipp; Pollheimer, Jürgen; Knöfler, Martin; Yung, Hong wa; Burton, Graham J.; Tabrizi-Wizsy, Nassim Ghaffari; Lang, Uwe; Hiden, Ursula; Desoye, Gernot; Dieber-Rotheneder, Martina

    2017-01-01

    STUDY QUESTION Does endothelin-1 (ET-1) regulate matrix metalloproteinase (MMP) 14 and 15 production and invasion of human first trimester trophoblasts? SUMMARY ANSWER ET-1 in pathophysiological concentrations down-regulates MMP14 and MMP15 expression via endothelin receptor (ETR) type B and decreases trophoblast migration and invasion. WHAT IS KNOWN ALREADY MMP14 and MMP15 are involved in trophoblast invasion. Impairment of invasion has been linked to pregnancy complications such as pre-eclampsia (PE). ET-1 is up-regulated in PE. STUDY DESIGN, SIZE, DURATION In vitro study using primary human trophoblasts from 50 first trimester placentas (gestational week 7–12). PARTICIPANTS/MATERIALS, SETTING, METHODS Trophoblasts were cultured in the absence or presence of 10–100 nM ET-1. MMP14 and MMP15 mRNA and protein were quantified by RT-qPCR and Western blotting, respectively. Selective antagonists for ETRA (BQ-123) or ETRB (BQ-788) were used to identify ETR subtypes involved. Functional ET-1 effects were tested in first trimester chorionic villous explants and transwell invasion assays. The roles of tumor necrosis factor (TNF)-α (25 ng/ml) and oxygen (1%) in ET-1 regulation of MMP14 and 15 expression were assessed by Western blotting. MAIN RESULTS AND THE ROLE OF CHANCE ET-1 down-regulated MMP14 and MMP15 mRNA (−21% and −26%, respectively, P < 0.05) and protein levels (–18% and –22%, respectively, P < 0.05). This effect was mediated via ETRB. ET-1 decreased trophoblast outgrowth in placental explants (−24%, P < 0.05) and trophoblast invasion (−26%, P ≤ 0.01). TNF-α enhanced ET-1 mediated MMP15 down-regulation (by 10%, P < 0.05), whereas hypoxia abolished the effect of ET-1 on both MMPs. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Only primary trophoblasts were used in this study. Since trophoblast yield from first trimester placental material is limited, further aspects of MMP14 and 15 regulation could not be characterized. Other anti

  2. Comparison of 2 endothelin-receptor antagonists on in vitro responses of equine palmar digital arterial and venous rings to endothelin-1

    PubMed Central

    Venugopal, Changaram S.; Hosgood, Giselle; Eades, Susan C.; Moore, Rustin M.

    2006-01-01

    Abstract The goals of this study were to determine the concentration–response (C–R) relationship of endothelin-1 (ET-1), compare 2 ET-receptor antagonists and determine the antagonist concentrations that block the vasomotor effects of ET-1, and compare the effectiveness of ET-1 and previously studied vasoconstrictors in equine palmar digital arterial and venous rings in vitro. Vessel rings from 8 nonlaminitic horses were placed in Tyrode’s solution, 1 side fixed to the floor of an organ bath and the other side fixed to a force-displacement transducer. Two separate studies were conducted: (I) incubation with a single ET-receptor antagonist (PD142893 or PD145065 at a concentration of 10−7, 10−6, or 10−5 M), followed by determination of an ET-1 C–R curve (using concentrations of 10−10 to 10−6 M) for medial vessel rings; and (II) comparison of ET-1 with norepinephrine and histamine (10−10 to 10−6 M) and comparison of contractile responses of medial and lateral vessel rings. In study I, ET-1 administration caused pronounced and sustained concentration-dependent contraction of vessel rings; these contractile responses were decreased by 10−5 M PD142893 and were completely blocked by 10−5 M PD145065. Venous rings had greater apparent maximum contraction in response to ET-1 than arterial rings. In study II, the relative sensitivity of norepinephrine was found to be equivalent to that of ET-1, whereas that of histamine was lower. No significant differences were observed between responses of medial versus lateral vessel rings. Thus, ET-1 is a potent vasoconstrictor of equine palmar digital arteries and veins, and the ET-receptor antagonist PD145065 is more effective than PD142893 in inhibiting these contractile effects in vitro. PMID:16850942

  3. Protein kinase mediated upregulation of endothelin A, endothelin B and 5-hydroxytryptamine 1B/1D receptors during organ culture in rat basilar artery

    PubMed Central

    Hansen-Schwartz, Jacob; Svensson, Carl-Lennart; Xu, Cang-Bao; Edvinsson, Lars

    2002-01-01

    Organ culture has been shown to upregulate both endothelin (ET) and 5-hydroxytryptamine 1B/1D (5-HT1B/1D) receptors in rat cerebral arteries. The purpose of the present study was to investigate the involvement of protein kinases, especially protein kinases C (PKC) and A (PKA) in this process. The effect of inhibiting protein kinases during organ culture with staurosporine (unspecific protein kinase inhitor), RO 31-7549 (specific inhibitor of classical PKC's) and H 89 (specific inhibitor of PKA) was examined using in vitro pharmacological examination of cultured vessel segments with ET-1 (unspecific ETA and ETB agonist), S6c (specific ETB agonist) and 5-CT (5-HT1 agonist). Levels of mRNA coding for the ETA, ETB, 5-HT1B and 5-HT1D receptors were analysed using real-time RT–PCR. Classical PKC's are critically involved in the appearance of the ETB receptor; co-culture with RO 31-7549 abolished the contractile response (6.9±1.8%) and reduced the ETB receptor mRNA by 44±4% as compared to the cultured control. Correlation between decreased ETB receptor mRNA and abolished contractile function indicates upstream involvement of PKC. Inhibition of PKA generally had an enhancing effect on the induced changes giving rise to a 7–25% increase in Emax in response to ET-1, S6c and 5-CT as compared to the cultured control. Staurosporine inhibited the culture induced upregulation of the response of both the ETA and the 5-HT1B/1D receptors, but had no significant effect on the mRNA levels of these receptors. This lack of correlation indicates an additional downstream involvement of protein kinases. PMID:12183337

  4. Adenosine A2A receptor and ecto-5'-nucleotidase/CD73 are upregulated in hippocampal astrocytes of human patients with mesial temporal lobe epilepsy (MTLE).

    PubMed

    Barros-Barbosa, Aurora R; Ferreirinha, Fátima; Oliveira, Ângela; Mendes, Marina; Lobo, M Graça; Santos, Agostinho; Rangel, Rui; Pelletier, Julie; Sévigny, Jean; Cordeiro, J Miguel; Correia-de-Sá, Paulo

    2016-12-01

    Refractoriness to existing medications of up to 80 % of the patients with mesial temporal lobe epilepsy (MTLE) prompts for finding new antiepileptic drug targets. The adenosine A2A receptor emerges as an interesting pharmacological target since its excitatory nature partially counteracts the dominant antiepileptic role of endogenous adenosine acting via inhibitory A1 receptors. Gain of function of the excitatory A2A receptor has been implicated in a significant number of brain pathologies commonly characterized by neuronal excitotoxicity. Here, we investigated changes in the expression and cellular localization of the A2A receptor and of the adenosine-generating enzyme, ecto-5'-nucleotidase/CD73, in the hippocampus of control individuals and MTLE human patients. Western blot analysis indicates that the A2A receptor is more abundant in the hippocampus of MTLE patients compared to control individuals. Immunoreactivity against the A2A receptor predominates in astrocytes staining positively for the glial fibrillary acidic protein (GFAP). No co-localization was observed between the A2A receptor and neuronal cell markers, like synaptotagmin 1/2 (nerve terminals) and neurofilament 200 (axon fibers). Hippocampal astrogliosis observed in MTLE patients was accompanied by a proportionate increase in A2A receptor and ecto-5'-nucleotidase/CD73 immunoreactivities. Given our data, we hypothesize that selective blockade of excessive activation of astrocytic A2A receptors and/or inhibition of surplus adenosine formation by membrane-bound ecto-5'-nucleotidase/CD73 may reduce neuronal excitability, thus providing a novel therapeutic target for drug-refractory seizures in MTLE patients.

  5. The Role of Endothelin System in Renal Structure and Function during the Postnatal Development of the Rat Kidney

    PubMed Central

    Albertoni Borghese, María F.; Ortiz, María C.; Balonga, Sabrina; Moreira Szokalo, Rocío; Majowicz, Mónica P.

    2016-01-01

    Renal development in rodents, unlike in humans, continues during early postnatal period. We aimed to evaluate whether the pharmacological inhibition of Endothelin system during this period affects renal development, both at structural and functional level in male and female rats. Newborn rats were treated orally from postnatal day 1 to 20 with vehicle or bosentan (Actelion, 20 mg/kg/day), a dual endothelin receptor antagonist (ERA). The animals were divided in 4 groups: control males, control females, ERA males and ERA females. At day 21, we evaluated renal function, determined the glomerular number by a maceration method and by morphometric analysis and evaluated possible structural renal alterations by three methods: 〈alpha〉-Smooth muscle actin (α-SMA) immunohistochemistry, Masson's trichrome and Sirius red staining. The pharmacological inhibition of Endothelin system with a dual ERA during the early postnatal period of the rat did not leads to renal damage in the kidneys of male and female rats. However, ERA administration decreased the number of glomeruli, the juxtamedullary filtration surface area and the glomerular filtration rate and increased the proteinuria. These effects could predispose to hypertension or renal diseases in the adulthood. On the other hand, these effects were more pronounced in male rats, suggesting that there are sex differences that could be greater later in life. These results provide evidence that Endothelin has an important role in rat renal postnatal development. However these results do not imply that the same could happen in humans, since human renal development is complete at birth. PMID:26872270

  6. Endothelin-1 but not Endothelial Nitric Oxide Synthase Gene Polymorphism is Associated with Sickle Cell Disease in Africa

    PubMed Central

    Thakur, Tanya J; Guindo, Aldiouma; Cullifer, Londyn R; Li, Yi; Imumorin, Ikhide G; Diallo, Dapa A; Thomas, Bolaji N

    2014-01-01

    Sickle cell disease shows marked variability in severity and pathophysiology among individuals, probably linked to differential expression of various adhesion molecules. In this study, we investigated the differential distribution, genomic diversity and haplotype frequency of endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) polymorphisms, recently implicated as important in modification of disease severity. One hundred and forty five sickle cell disease patients (HbSS) and 244 adult and pediatric controls, without sickle cell disease (HbAA), were recruited from Mali. Genotypic analysis of the functionally significant eNOS variants (T786C, G894T and intron 4) and endothelin-1 (G5665T) was carried out with a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Our results show that the wild type alleles are the most frequent for all eNOS variants between cases and controls. Allelic and genotypic frequencies of eNOS polymorphic groups are not significantly different between cases and controls (P > 0.05). In addition, there is no association between eNOS variants and sickle cell disease, contrary to published reports. On the other hand, we report that endothelin-1 (G5665T) mutant variant had the lowest allelic frequency, and is significantly associated with sickle cell disease in Africa (P < 0.05). Similarly, haplotype frequencies were the same between cases and controls, except for the haplotype combining all mutant variants (T, C, 4a; P = 0.01). eNOS polymorphic variants are less frequent, with no significance with sickle cell disease in Africa. On the other hand, endothelin-1 is associated with sickle cell disease, and has the capacity to redefine pathophysiology and possibly serve as modulator of disease phenotype. PMID:24932102

  7. Endothelin-1 but not Endothelial Nitric Oxide Synthase Gene Polymorphism is Associated with Sickle Cell Disease in Africa.

    PubMed

    Thakur, Tanya J; Guindo, Aldiouma; Cullifer, Londyn R; Li, Yi; Imumorin, Ikhide G; Diallo, Dapa A; Thomas, Bolaji N

    2014-01-01

    Sickle cell disease shows marked variability in severity and pathophysiology among individuals, probably linked to differential expression of various adhesion molecules. In this study, we investigated the differential distribution, genomic diversity and haplotype frequency of endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) polymorphisms, recently implicated as important in modification of disease severity. One hundred and forty five sickle cell disease patients (HbSS) and 244 adult and pediatric controls, without sickle cell disease (HbAA), were recruited from Mali. Genotypic analysis of the functionally significant eNOS variants (T786C, G894T and intron 4) and endothelin-1 (G5665T) was carried out with a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Our results show that the wild type alleles are the most frequent for all eNOS variants between cases and controls. Allelic and genotypic frequencies of eNOS polymorphic groups are not significantly different between cases and controls (P > 0.05). In addition, there is no association between eNOS variants and sickle cell disease, contrary to published reports. On the other hand, we report that endothelin-1 (G5665T) mutant variant had the lowest allelic frequency, and is significantly associated with sickle cell disease in Africa (P < 0.05). Similarly, haplotype frequencies were the same between cases and controls, except for the haplotype combining all mutant variants (T, C, 4a; P = 0.01). eNOS polymorphic variants are less frequent, with no significance with sickle cell disease in Africa. On the other hand, endothelin-1 is associated with sickle cell disease, and has the capacity to redefine pathophysiology and possibly serve as modulator of disease phenotype.

  8. Evaluation of the safety of epinephrine in digital nerve blockade

    PubMed Central

    Chapeskie, Henry; Juliao, Alexis; Payne, Sonja; Koichopolos, Jennifer

    2016-01-01

    Abstract Objective To evaluate the safety profile of lidocaine containing 1:200 000 to 1:100 000 epinephrine with concurrent tourniquet use in patients undergoing toe surgery. Design A retrospective case series analysis of toe procedures performed under digital blockade with adjuvant vasopressor from January 25, 2009, to May 31, 2014, was conducted. Exclusion criteria were limited to procedures performed without adjuvant vasopressor use. Setting A single clinic in Ontario. Participants A total of 1334 toe procedures performed in 937 patients. Main outcome measures The primary study outcome was the incidence of postoperative digital necrosis. Secondary outcomes included other postoperative complications including infection, reperfusion injury, persistent granulation, and damage to the nail matrix. Results In total, 1334 toe procedures were included in this study, of which 45 involved patients with a pre-existing diagnosis of diabetes mellitus. The overall incidence of postoperative complications was low (4.6%). No cases of digital ischemia or gangrenous necrosis were observed. Subgroup analysis of patients with and without diabetes showed no statistically significant difference in the rate of complications. Conclusion This study demonstrates the safety of adjuvant vasopressor use in digital nerve blockade of the toes within a large, diverse population. This study adds to a growing base of evidence on the safety of lidocaine with 1:200 000 to 1:100 000 epinephrine for digital anesthesia.

  9. Angiopoietin-2 Blockade Promotes Survival of Corneal Transplants

    PubMed Central

    Zhang, Liwei; Li, Guangyu; Sessa, Roberto; Kang, Gyeong Jin; Shi, Meng; Ge, Shaokui; Gong, Anna Jiang; Wen, Ying; Chintharlapalli, Sudhakar; Chen, Lu

    2017-01-01

    Purpose Corneal transplantation remains the last hope for vision restoration, and lymphangiogenesis (LG) is a primary mediator of transplant rejection. This study was to investigate the specific role of angiopoietin-2 (Ang-2) in transplantation-associated LG and graft rejection. Methods Orthotopic corneal transplantation was performed between fully mismatched C57BL/6 (donor) and BALB/c (recipient) mice to assess the effects of Ang-2 blockade via neutralizing antibody. Grafts were evaluated in vivo by ophthalmic slit-lamp biomicroscopy and anterior segment optical coherence tomography (OCT) up to 8 weeks after surgery. Additionally, whole-mount corneas were analyzed for lymphatic and blood vessels and macrophages by immunofluorescent microscopy, and draining lymph nodes were assessed for donor-derived cells by flow cytometry. Results Anti-Ang-2 treatment significantly suppressed LG and graft rejection. In this study, we achieved 75% suppression of LG and 80% graft survival. Our approach also inhibited donor-derived cell trafficking to draining lymph nodes and affected macrophage morphologic phenotypes in the grafted corneas. Additionally, Ang-2 blockade also reduced central corneal thickening, a parameter strongly associated with graft rejection. Conclusions Ang-2 is critically involved in corneal transplant rejection and anti-Ang-2 treatment significantly improves the outcomes of corneal grafts. Moreover, we have shown that anterior segment OCT offers a new tool to monitor murine corneal grafts in vivo. This study not only reveals new mechanisms for transplant rejection, but also offers a novel strategy to treat it. PMID:28061513

  10. CTLA4 blockade broadens the peripheral T cell receptor repertoire

    PubMed Central

    Robert, Lidia; Tsoi, Jennifer; Wang, Xiaoyan; Emerson, Ryan; Homet, Blanca; Chodon, Thinle; Mok, Stephen; Huang, Rong Rong; Cochran, Alistair J.; Comin-Anduix, Begonya; Koya, Richard C.; Graeber, Thomas G.; Robins, Harlan; Ribas, Antoni

    2014-01-01

    Purpose To evaluate the immunomodulatory effects of CTLA-4 blockade with tremelimumab in peripheral blood mononuclear cells (PBMC). Experimental Design We used next generation sequencing to study the complementarity determining region 3 (CDR3) from the rearranged T cell receptor (TCR) variable beta (V-beta) in PBMC of 21 patients, at baseline and 30–60 days after receiving tremelimumab. Results After receiving tremelimumab there was a median of 30% increase in unique productive sequences of TCR V-beta CDR3 in 19 out of 21 patients, and a median decrease of 30% in only 2 out of 21 patients. These changes were significant for richness (p=0.01) and for Shannon index diversity (p=0.04). In comparison, serially collected PBMC from four healthy donors did not show a significant change in TCR V-beta CDR3 diversity over one year. There was a significant difference in the total unique productive TCR V-beta CDR3 sequences between patients experiencing toxicity with tremelimumab compared to patients without toxicity (p=0.05). No relevant differences were noted between clinical responders and non-responders. Conclusions CTLA4 blockade with tremelimumab diversifies the peripheral T cell pool, representing a pharmacodynamic effect of how this class of antibodies modulates the human immune system. PMID:24583799

  11. Inactivation gating determines nicotine blockade of human HERG channels.

    PubMed

    Wang, H Z; Shi, H; Liao, S J; Wang, Z

    1999-09-01

    We have previously found that nicotine blocked multiple K+ currents, including the rapid component of delayed rectifier K+ currents (IKr), by interacting directly with the channels. To shed some light on the mechanisms of interaction between nicotine and channels, we performed detailed analysis on the human ether-à-go-go-related gene (HERG) channels, which are believed to be equivalent to the native I(Kr) when expressed in Xenopus oocytes. Nicotine suppressed the HERG channels in a concentration-dependent manner with greater potency with voltage protocols, which favor channel inactivation. Nicotine caused dramatic shifts of the voltage-dependent inactivation curve to more negative potentials and accelerated the inactivation process. Conversely, maneuvers that weakened the channel inactivation gating considerably relieved the blockade. Elevating the extracellular K+ concentration from 5 to 20 mM increased the nicotine concentration (by approximately 100-fold) needed to achieve the same degree of inhibition. Moreover, nicotine lost its ability to block the HERG channels when a single mutation was introduced to a residue located after transmembrane domain 6 (S631A) to remove the rapid channel inactivation. Our data suggest that the inactivation gating determines nicotine blockade of the HERG channels.

  12. Chlorpheniramine produces spinal motor, proprioceptive and nociceptive blockades in rats.

    PubMed

    Tzeng, Jann-Inn; Lin, Heng-Teng; Chen, Yu-Wen; Hung, Ching-Hsia; Wang, Jhi-Joung

    2015-04-05

    This study aimed to assess the local anesthetic effects of chlorpheniramine in spinal anesthesia and is compared with mepivacaine, a widely-used local anesthetic. Spinal anesthesia with chlorpheniramine and mepivacaine was constructed in a dosage-dependent fashion after the rats were injected intrathecally. The spinal block effect of chlorpheniramine in motor function, nociception, and proprioception was compared to that of mepivacaine. We revealed that intrathecal chlorpheniramine and mepivacaine exhibited a dose-dependent spinal block of motor function, nociception, and proprioception. On the 50% effective dose (ED50) basis, the ranks of potencies in motor function, nociception, and proprioception were chlorpheniramine>mepivacaine (P<0.01 for the differences). On the equianesthetic basis (ED25, ED50, ED75), the duration of spinal anesthesia with chlorpheniramine was greater than that of mepivacaine (P<0.01 for the differences). Instead of mepivacaine, chlorpheniramine produced a greater duration of sensory blockade than the motor blockade. These preclinical data showed that chlorpheniramine has a better sensory-selective action over motor block to produce more potent and long-lasting spinal anesthesia than mepivacaine.

  13. Emerging role of checkpoint blockade therapy in lymphoma

    PubMed Central

    Galanina, Natalie; Kline, Justin; Bishop, Michael R.

    2017-01-01

    Following the successful application of immune checkpoint blockade therapy (CBT) in refractory solid tumors, it has recently gained momentum as a promising modality in the treatment of relapsed lymphoma. This significant therapeutic advance stems from decades of research that elucidated the role of immune regulation pathways and the mechanisms by which tumors can engage these critical pathways to escape immune detection. To date, two main pathways, the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1), have emerged as key targets of CBT demonstrating unprecedented activity particularly in heavily pretreated relapsed/refractory Hodgkin lymphoma and some forms of non-Hodgkin disease. Herein we provide a brief discussion of checkpoint blockade in the context of lymphoma biology with a specific focus on novel checkpoint inhibitors and their therapeutic activity. We discuss current clinical trials and the landscape of CBT to underscore both the remarkable progress and foreseeable limitations of this novel treatment strategy. In particular, we build upon state-of-the-art knowledge and clinical insights gained from the early trials to review potential approaches to how CBT may be integrated with other treatment modalities, including chemoimmunotherapy to improve patient outcomes in the future. Finally, as the role of CBT evolves to potentially become a cornerstone of therapy in refractory/relapsed lymphoma, we briefly emphasize the importance of predictive biomarkers in an effort to select appropriate patients who are most likely to derive benefit from CBT. PMID:28203344

  14. Functional improvement of dystrophic muscle by myostatin blockade.

    PubMed

    Bogdanovich, Sasha; Krag, Thomas O B; Barton, Elisabeth R; Morris, Linda D; Whittemore, Lisa-Anne; Ahima, Rexford S; Khurana, Tejvir S

    2002-11-28

    Mice and cattle with mutations in the myostatin (GDF8) gene show a marked increase in body weight and muscle mass, indicating that this new member of the TGF-beta superfamily is a negative regulator of skeletal muscle growth. Inhibition of the myostatin gene product is predicted to increase muscle mass and improve the disease phenotype in a variety of primary and secondary myopathies. We tested the ability of inhibition of myostatin in vivo to ameliorate the dystrophic phenotype in the mdx mouse model of Duchenne muscular dystrophy (DMD). Blockade of endogenous myostatin by using intraperitoneal injections of blocking antibodies for three months resulted in an increase in body weight, muscle mass, muscle size and absolute muscle strength in mdx mouse muscle along with a significant decrease in muscle degeneration and concentrations of serum creatine kinase. The functional improvement of dystrophic muscle by myostatin blockade provides a novel, pharmacological strategy for treatment of diseases associated with muscle wasting such as DMD, and circumvents the major problems associated with conventional gene therapy in these disorders.

  15. OX40L blockade protects against inflammation-driven fibrosis

    PubMed Central

    Elhai, Muriel; Avouac, Jérôme; Hoffmann-Vold, Anna Maria; Ruzehaji, Nadira; Amiar, Olivia; Ruiz, Barbara; Brahiti, Hassina; Ponsoye, Matthieu; Fréchet, Maxime; Burgevin, Anne; Pezet, Sonia; Sadoine, Jérémy; Guilbert, Thomas; Nicco, Carole; Akiba, Hisaya; Heissmeyer, Vigo; Subramaniam, Arun; Resnick, Robert; Molberg, Øyvind; Kahan, André; Chiocchia, Gilles; Allanore, Yannick

    2016-01-01

    Treatment for fibrosis represents a critical unmet need, because fibrosis is the leading cause of death in industrialized countries, and there is no effective therapy to counteract the fibrotic process. The development of fibrosis relates to the interplay between vessel injury, immune cell activation, and fibroblast stimulation, which can occur in various tissues. Immunotherapies have provided a breakthrough in the treatment of immune diseases. The glycoprotein OX40–OX40 ligand (OX40L) axis offers the advantage of a targeted approach to costimulatory signals with limited impact on the whole immune response. Using systemic sclerosis (SSc) as a prototypic disease, we report compelling evidence that blockade of OX40L is a promising strategy for the treatment of inflammation-driven fibrosis. OX40L is overexpressed in the fibrotic skin and serum of patients with SSc, particularly in patients with diffuse cutaneous forms. Soluble OX40L was identified as a promising serum biomarker to predict the worsening of lung and skin fibrosis, highlighting the role of this pathway in fibrosis. In vivo, OX40L blockade prevents inflammation-driven skin, lung, and vessel fibrosis and induces the regression of established dermal fibrosis in different complementary mouse models. OX40L exerts potent profibrotic effects by promoting the infiltration of inflammatory cells into lesional tissues and therefore the release of proinflammatory mediators, thereafter leading to fibroblast activation. PMID:27298374

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

    PubMed Central

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

    2014-01-01

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

  17. Selective astrocytic endothelin-1 overexpression contributes to dementia associated with ischemic stroke by exaggerating astrocyte-derived amyloid secretion

    PubMed Central

    Hung, Victor K L; Yeung, Patrick K K; Lai, Angela K W; Ho, Maggie C Y; Lo, Amy C Y; Chan, Kevin C; Wu, Ed X K; Chung, Stephen S M; Cheung, Chi W; Chung, Sookja K

    2015-01-01

    Endothelin-1 (ET-1) is synthesized by endothelial cells and astrocytes in stroke and in brains of Alzheimer's disease patients. Our transgenic mice with ET-1 overexpression in the endothelial cells (TET-1) showed more severe blood–brain barrier (BBB) breakdown, neuronal apoptosis, and glial reactivity after 2-hour transient middle cerebral artery occlusion (tMCAO) with 22-hour reperfusion and more severe cognitive deficits after 30 minutes tMCAO with 5 months reperfusion. However, the role of astrocytic ET-1 in contributing to poststroke cognitive deficits after tMCAO is largely unknown. Therefore, GET-1 mice were challenged with tMCAO to determine its effect on neurologic and cognitive deficit. The GET-1 mice transiently displayed a sensorimotor deficit after reperfusion that recovered shortly, then more severe deficit in spatial learning and memory was observed at 3 months after ischemia compared with that of the controls. Upregulation of TNF-α, cleaved caspase-3, and Thioflavin-S-positive aggregates was observed in the ipsilateral hemispheres of the GET-1 brains as early as 3 days after ischemia. In an in vitro study, ET-1 overexpressing astrocytic cells showed amyloid secretion after hypoxia/ischemia insult, which activated endothelin A (ETA) and endothelin B (ETB) receptors in a PI3K/AKT-dependent manner, suggesting role of astrocytic ET-1 in dementia associated with stroke by astrocyte-derived amyloid production. PMID:26104290

  18. UVB radiation generates sunburn pain and affects skin by activating epidermal TRPV4 ion channels and triggering endothelin-1 signaling

    PubMed Central

    Moore, Carlene; Cevikbas, Ferda; Pasolli, H. Amalia; Chen, Yong; Kong, Wei; Kempkes, Cordula; Parekh, Puja; Lee, Suk Hee; Kontchou, Nelly-Ange; Yeh, Iwei; Jokerst, Nan Marie; Fuchs, Elaine; Steinhoff, Martin; Liedtke, Wolfgang B.

    2013-01-01

    At our body surface, the epidermis absorbs UV radiation. UV overexposure leads to sunburn with tissue injury and pain. To understand how, we focus on TRPV4, a nonselective cation channel highly expressed in epithelial skin cells and known to function in sensory transduction, a property shared with other transient receptor potential channels. We show that following UVB exposure mice with induced Trpv4 deletions, specifically in keratinocytes, are less sensitive to noxious thermal and mechanical stimuli than control animals. Exploring the mechanism, we find that epidermal TRPV4 orchestrates UVB-evoked skin tissue damage and increased expression of the proalgesic/algogenic mediator endothelin-1. In culture, UVB causes a direct, TRPV4-dependent Ca2+ response in keratinocytes. In mice, topical treatment with a TRPV4-selective inhibitor decreases UVB-evoked pain behavior, epidermal tissue damage, and endothelin-1 expression. In humans, sunburn enhances epidermal expression of TRPV4 and endothelin-1, underscoring the potential of keratinocyte-derived TRPV4 as a therapeutic target for UVB-induced sunburn, in particular pain. PMID:23929777

  19. UVB radiation generates sunburn pain and affects skin by activating epidermal TRPV4 ion channels and triggering endothelin-1 signaling.

    PubMed

    Moore, Carlene; Cevikbas, Ferda; Pasolli, H Amalia; Chen, Yong; Kong, Wei; Kempkes, Cordula; Parekh, Puja; Lee, Suk Hee; Kontchou, Nelly-Ange; Yeh, Iwei; Ye, Iwei; Jokerst, Nan Marie; Fuchs, Elaine; Steinhoff, Martin; Liedtke, Wolfgang B

    2013-08-20

    At our body surface, the epidermis absorbs UV radiation. UV overexposure leads to sunburn with tissue injury and pain. To understand how, we focus on TRPV4, a nonselective cation channel highly expressed in epithelial skin cells and known to function in sensory transduction, a property shared with other transient receptor potential channels. We show that following UVB exposure mice with induced Trpv4 deletions, specifically in keratinocytes, are less sensitive to noxious thermal and mechanical stimuli than control animals. Exploring the mechanism, we find that epidermal TRPV4 orchestrates UVB-evoked skin tissue damage and increased expression of the proalgesic/algogenic mediator endothelin-1. In culture, UVB causes a direct, TRPV4-dependent Ca(2+) response in keratinocytes. In mice, topical treatment with a TRPV4-selective inhibitor decreases UVB-evoked pain behavior, epidermal tissue damage, and endothelin-1 expression. In humans, sunburn enhances epidermal expression of TRPV4 and endothelin-1, underscoring the potential of keratinocyte-derived TRPV4 as a therapeutic target for UVB-induced sunburn, in particular pain.

  20. Selective adenosine A2A receptor agonists and antagonists protect against spinal cord injury through peripheral and central effects

    PubMed Central

    2011-01-01

    of the A2A agonist are due to A2A receptor desensitization. When the A2A antagonist and agonist were centrally injected into injured SC, only SCH58261 appeared neuroprotective, while CGS21680 was ineffective. Conclusions Our results indicate that the A2A antagonist protects against SCI by acting on centrally located A2A receptors. It is likely that blockade of A2A receptors reduces excitotoxicity. In contrast, neuroprotection afforded by the A2A agonist may be primarily due to peripheral effects. PMID:21486435

  1. Angiotensin II type 1a receptor signalling directly contributes to the increased arrhythmogenicity in cardiac hypertrophy

    PubMed Central

    Yasuno, Shinji; Kuwahara, Koichiro; Kinoshita, Hideyuki; Yamada, Chinatsu; Nakagawa, Yasuaki; Usami, Satoru; Kuwabara, Yoshihiro; Ueshima, Kenji; Harada, Masaki; Nishikimi, Toshio; Nakao, Kazuwa

    2013-01-01

    BACKGROUND AND PURPOSE Angiotensin II has been implicated in the development of various cardiovascular ailments, including cardiac hypertrophy and heart failure. The fact that inhibiting its signalling reduced the incidences of both sudden cardiac death and heart failure in several large-scale clinical trials suggests that angiotensin II is involved in increased cardiac arrhythmogenicity during the development of heart failure. However, because angiotensin II also promotes structural remodelling, including cardiomyocyte hypertrophy and cardiac fibrosis, it has been difficult to assess its direct contribution to cardiac arrhythmogenicity independently of the structural effects. EXPERIMENTAL APPROACH We induced cardiac hypertrophy in wild-type (WT) and angiotensin II type 1a receptor knockout (AT1aR-KO) mice by transverse aortic constriction (TAC). The susceptibility to ventricular tachycardia (VT) assessed in an in vivo electrophysiological study was compared in the two genotypes. The effect of acute pharmacological blockade of AT1R on the incidences of arrhythmias was also assessed. KEY RESULTS As described previously, WT and AT1aR-KO mice with TAC developed cardiac hypertrophy to the same degree, but the incidence of VT was much lower in the latter. Moreover, although TAC induced an increase in tyrosine phosphorylation of connexin 43, a critical component of gap junctional channels, and a reduction in ventricular levels of connexin 43 protein in both genotypes, the effect was significantly ameliorated in AT1aR-KO mice. Acute pharmacological blockade of AT1R also reduced the incidence of arrhythmias. CONCLUSIONS AND IMPLICATIONS Our findings demonstrate that AT1aR-mediated signalling makes a direct contribution to the increase in arrhythmogenicity in hypertrophied hearts independently of structural remodelling. PMID:23937445

  2. Caffeine and adenosine A(2a) receptor antagonists prevent beta-amyloid (25-35)-induced cognitive deficits in mice.

    PubMed

    Dall'Igna, Oscar P; Fett, Paulo; Gomes, Marcio W; Souza, Diogo O; Cunha, Rodrigo A; Lara, Diogo R

    2007-01-01

    Consumption of caffeine, an adenosine receptor antagonist, was found to be inversely associated with the incidence of Alzheimer's disease. Moreover, caffeine protects cultured neurons against beta-amyloid-induced toxicity, an effect mimicked by adenosine A(2A) but not A(1) receptor antagonists. We now tested if caffeine administration would prevent beta-amyloid-induced cognitive impairment in mice and if this was mimicked by A(2A) receptor blockade. One week after icv administration of the 25-35 fragment of beta-amyloid (Abeta, 3 nmol), mice displayed impaired performance in both inhibitory avoidance and spontaneous alternation tests. Prolonged treatment with caffeine (1 mg/ml) had no effect alone but prevented the Abeta-induced cognitive impairment in both tasks when associated with acute caffeine (30 mg/kg) 30 min treatment before Abeta administration. The same protective effect was observed after subchronic (4 days) treatment with daily injections of either caffeine (30 mg/kg) or the selective adenosine A(2A) receptor antagonist SCH58261 (0.5 mg/kg). This provides the first direct in vivo evidence that caffeine and A(2A) receptor antagonists afford a protection against Abeta-induced amnesia, which prompts their interest for managing Alzheimer's disease.

  3. Aldosterone Inactivates the Endothelin-B Receptor via a Cysteinyl Thiol Redox Switch to Decrease Pulmonary Endothelial Nitric Oxide Levels and Modulate Pulmonary Arterial Hypertension

    PubMed Central

    Maron, Bradley A.; Zhang, Ying-Yi; White, Kevin; Chan, Stephen Y.; Handy, Diane E.; Mahoney, Christopher E.; Loscalzo, Joseph; Leopold, Jane A.

    2012-01-01

    Background Pulmonary arterial hypertension (PAH) is characterized, in part, by decreased endothelial nitric oxide (NO•) production and elevated levels of endothelin-1. Endothelin-1 is known to stimulate endothelial nitric oxide synthase (eNOS) via the endothelin-B receptor (ETB), suggesting that this signaling pathway is perturbed in PAH. Endothelin-1 also stimulates adrenal aldosterone synthesis; in systemic blood vessels, hyperaldosteronism induces vascular dysfunction by increasing endothelial reactive oxygen species (ROS) generation and decreasing NO• levels. We hypothesized that aldosterone modulates PAH by disrupting ETB-eNOS signaling through a mechanism involving increased pulmonary endothelial oxidant stress. Methods and Results In rats with PAH, elevated endothelin-1 levels were associated with elevated aldosterone levels in plasma and lung tissue and decreased lung NO• metabolites in the absence of left heart failure. In human pulmonary artery endothelial cells (HPAECs), endothelin-1 increased aldosterone levels via PGC-1α/steroidogenesis factor-1-dependent upregulation of aldosterone synthase. Aldosterone also increased ROS production, which oxidatively modified cysteinyl thiols in the eNOS-activating region of ETB to decrease endothelin-1-stimulated eNOS activity. Substitution of ETB-Cys405 with alanine improved ETB-dependent NO• synthesis under conditions of oxidant stress, confirming that Cys405 is a redox sensitive thiol that is necessary for ETB-eNOS signaling. In HPAECs, mineralocorticoid receptor antagonism with spironolactone decreased aldosterone-mediated ROS generation and restored ETB-dependent NO• production. Spironolactone or eplerenone prevented or reversed pulmonary vascular remodeling and improved cardiopulmonary hemodynamics in two animal models of PAH in vivo. Conclusions Our findings demonstrate that aldosterone modulates an ETB cysteinyl thiol redox switch to decrease pulmonary endothelium-derived NO• and promote PAH

  4. Beta-adrenoceptor blockade and atrio-ventricular conduction in dogs. Role of intrinsic sympathomimetic activity.

    PubMed

    Giudicelli, J F; Lhoste, F

    1982-01-01

    1 Atrio-ventricular conduction and its modifications induced by six beta-adrenoceptor blocking agents and isoprenaline have been investigated in the anaesthetized dog using the extrastimulus technique and measuring atrial (AERP), nodal (NERP), global (GERP) effective refractory periods as well as global functional refractory period (GFRP). 2 When beta-adrenoceptor blockade was produced by (+/-)-propranolol (beta 1 + beta 2-adrenoceptor blockade) which is devoid of intrinsic sympathomimetic activity (ISA) but has membrane stabilizing effects (MSE), sotalol (beta 1 + beta 2-adrenoceptor blockade, no ISA, no MSE) and atenolol (beta 1-adrenoceptor blockade, no ISA, no MSE), all parameters were significantly increased. When beta-adrenoceptor blockade was achieved with pindolol (beta 1 + beta 2-adrenoceptor blockade) and practolol (beta 1-adrenoceptor blockade) which have ISA but no MSE, all parameters remained unchanged, as was also the case with (+)-propranolol, which has MSE but neither ISA nor beta-adrenolytic properties. 3 Isoprenaline at high doses significantly reduced the refractory periods but when infusion was stopped, marked but reversible conduction depression was observed. 4 It thus appears that beta-adrenoceptor blockade but not MSE is responsible for the onset of atrial and AV-conduction impairment and that ISA affords protection against this impairment.

  5. Fasting influences steroidogenesis, vascular endothelial growth factor (VEGF) levels and mRNAs expression for VEGF, VEGF receptor type 2 (VEGFR-2), endothelin-1 (ET-1), endothelin receptor type A (ET-A) and endothelin converting enzyme-1 (ECE-1) in newly formed pig corpora lutea.

    PubMed

    Galeati, Giovanna; Forni, Monica; Spinaci, Marcella; Zannoni, Augusta; Govoni, Nadia; Ribeiro, Luciana A; Seren, Eraldo; Tamanini, Carlo

    2005-04-01

    This study was designed to verify whether fasting influences vascular endothelial growth factor (VEGF) production and VEGF, VEGF receptor-2 (VEGFR-2) as well as endothelin (ET) system members (endothelin converting enzyme-1, ECE-1; ET-1; endothelin receptor type A, ET-A) mRNA expression in pig corpora lutea; furthermore, we wanted to assess whether fasting affects steroidogenesis in luteal cells. Eight prepubertal gilts were induced to ovulate and were randomly assigned to two groups: (A) n = 4, normally fed; and (B) n = 4, fasted for 72 h starting 3 days after ovulation. At the end of fasting, ovaries were removed from all the animals and corpora lutea (CLs) were collected. VEGF and steroid levels in luteal tissue were determined by ELISA and RIA, respectively; VEGF, VEGFR-2, ET-1, ET-A and ECE-1 mRNAs expression was measured by real-time PCR. VEGF protein levels were similar in the two groups, while all steroid (progesterone, testosterone, estradiol 17beta) concentrations were significantly (P < 0.001) higher in CLs collected from fasted animals compared with those from normally fed gilts. VEGF, VEGFR-2, ET-1 and ECE-1 (but not ET-A) mRNA expression was significantly lower (P < 0.05) in fasted versus normally fed animals. The overall conclusion is that all the parameters studied are affected by feed restriction, but the mechanisms activated at luteal level are possibly not fully adequate to compensate for nutrient shortage.

  6. Functional measures, inflammatory markers and endothelin-1 as predictors of 360-day survival in centenarians.

    PubMed

    Szewieczek, Jan; Francuz, Tomasz; Dulawa, Jan; Legierska, Katarzyna; Hornik, Beata; Włodarczyk, Iwona; Janusz-Jenczeń, Magdalena; Batko-Szwaczka, Agnieszka

    2015-10-01

    Centenarians represent a rapidly growing population. To better characterize this specific age group, we have performed a cross-sectional study to observe associations between functional measures and a range of biochemical markers, including inflammatory markers and their significance as predictors of 360-day survival. Medical history and physical and functional assessment (Mini-Mental State Examination (MMSE), Katz Index (activities of daily living, ADL) and Barthel Index (Barthel Index) of Activities of Daily Living, and Lawton Instrumental Activities of Daily Living Scale (Lawton IADL)) were conducted on 86 101.9 ± 1.2-year-old (mean ± SD) subjects (70 women, 16 men). Blood tests were performed on 84 subjects of whom 43 also had extended biomarker assessment. As a reference group 30 51.8 ± 5.0-year old healthy subjects (20 women, 10 men) were recruited. The centenarians received follow-up phone calls. Fifty-two centenarians (60 %) survived ≥360 days. Longer survival was associated with higher MMSE (hazard ratio, HR = 0.934, 95 % confidence interval (CI) 0.896-0.975, P = .002), ADL (HR = 0.840, 95 % CI 0.716-0.985, P = .032), Barthel Index (HR = 0.988, 95 % CI 0.977-0.999, P = .026), and albumin level (HR .926, 95 % CI 0.870-0.986, P .016) and with lower white blood cell (WBC) (HR = 1.161, 95 % CI 1.059-1.273, P = .001), C-reactive protein (CRP) (HR = 1.032, 95 % CI 1.014-1.050, P < .001), IL-6 (HR = 1.182, 95 % CI 1.047-1.335, P = .007), and endothelin-1 (ET-1) level (HR = 3.711, 95 % CI 1.233-11.169, P = .020). Centenarians had higher 360-day survival probability with MMSE ≥13 (P < .001), ADL ≥1 (P < .001), Barthel Index ≥15 (P < .001), Lawton IADL ≥10 points (P = .009), WBC <8.3 G/L (P = .039), CRP <10 mg/L (P < .001), IL-6 <6 pg/mL (P .002), and ET-1 <1.1 pg/mL (P .007). Our results indicate that functional measures, inflammatory markers, and endothelin-1 are predictors of 360-day survival in centenarians.

  7. Prostanoids counterbalance the synergism between endothelin-1 and angiotensin II in mesenteric veins of trained rats.

    PubMed

    Chies, Agnaldo Bruno; de Oliveira, Priscilla Bianca; Rossignoli, Patrícia de Souza; Baptista, Rafaela de Fátima Ferreira; de Lábio, Roger William; Payão, Spencer Luiz Marques

    2017-02-01

    Exercise-induced adaptations of the modulating mechanisms that influence the angiotensin (Ang II) responses assume different features depending on the venous bed. In femoral veins, exercise mobilizes vasodilator prostanoids to cooperate with NO in order to maintain reduced Ang II responses. On the other hand, exercise's influence on the Ang II responses in veins that drain blood from the mesenteric region has been poorly described. Therefore, the present study aimed to identify the effects of a single bout of exercise, as well as exercise training, on the Ang II responses in mesenteric veins. The present study also aimed to investigate the involvement of prostanoids, NO and ET-1 in eventual exercise-induced modifications in these veins. To this end, mesenteric veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in organ baths. In addition, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as that of the ETA and ETB receptors, were quantified by real-time PCR in these veins. The results show that, either in absence or in presence of L-NAME, the Ang II responses were not different between groups. In the presence of indomethacin, higher Ang II responses were observed in the resting-trained animals than in the resting-sedentary animals. This difference, however, disappeared when L-NAME, BQ-123 or BQ-788 were added during incubation. In addition, no differences in ppET-1, ETA or ETB mRNA expression were observed between groups. Furthermore, in the presence of PD123,319, the Ang II responses in the exercised-sedentary animals were higher than those in the resting-sedentary animals. In conclusion, exercise training mobilizes endothelin-1 (ET-1) to reinforce the Ang II-induced responses mainly through ETA activation. On the other hand, vasodilator prostanoids are mobilized to act in parallel with NO in order to counterbalance the Ang II responses that have been potentiated by ET-1 in these trained

  8. Combined exposure to big endothelin-1 and mechanical loading in bovine sternal cores promotes osteogenesis.

    PubMed

    Meyer, Luisa A; Johnson, Michael G; Cullen, Diane M; Vivanco, Juan F; Blank, Robert D; Ploeg, Heidi-Lynn; Smith, Everett L

    2016-04-01

    Increased bone formation resulting from mechanical loading is well documented; however, the interactions of the mechanotransduction pathways are less well understood. Endothelin-1, a ubiquitous autocrine/paracrine signaling molecule promotes osteogenesis in metastatic disease. In the present study, it was hypothesized that exposure to big endothelin-1 (big ET1) and/or mechanical loading would promote osteogenesis in ex vivo trabecular bone cores. In a 2×2 factorial trial of daily mechanical loading (-2000με, 120cycles daily, "jump" waveform) and big ET1 (25ng/mL), 48 bovine sternal trabecular bone cores were maintained in bioreactor chambers for 23days. The bone cores' response to the treatment stimuli was assessed with percent change in core apparent elastic modulus (ΔEapp), static and dynamic histomorphometry, and prostaglandin E2 (PGE2) secretion. Two-way ANOVA with a post hoc Fisher's LSD test found no significant treatment effects on ΔEapp (p=0.25 and 0.51 for load and big ET1, respectively). The ΔEapp in the "no load + big ET1" (CE, 13±12.2%, p=0.56), "load + no big ET1" (LC, 17±3.9%, p=0.14) and "load + big ET1" (LE, 19±4.2%, p=0.13) treatment groups were not statistically different than the control group (CC, 3.3%±8.6%). Mineralizing surface (MS/BS), mineral apposition (MAR) and bone formation rates (BFR/BS) were significantly greater in LE than CC (p=0.037, 0.0040 and 0.019, respectively). While the histological bone formation markers in LC trended to be greater than CC (p=0.055, 0.11 and 0.074, respectively) there was no difference between CE and CC (p=0.61, 0.50 and 0.72, respectively). Cores in LE and LC had more than 50% greater MS/BS (p=0.037, p=0.055 respectively) and MAR (p=0.0040, p=0.11 respectively) than CC. The BFR/BS was more than two times greater in LE (p=0.019) and LC (p=0.074) than CC. The PGE2 levels were elevated at 8days post-osteotomy in all groups and the treatment groups remained elevated compared to the CC group on days 15

  9. Hyperinsulinaemia increases vascular resistance and endothelin-1 expression in the equine digit

    PubMed Central

    GAUFF, F.; PATAN-ZUGAJ, B.; LICKA, T. F.

    2014-01-01

    Summary Reasons for performing study Insulin leads to overexpression of endothelin-1 (ET-1) in the endothelium of insulin-resistant rodents. If this is also the case in equine laminar tissue, this could explain the predisposition of insulin-resistant horses to laminitis. Objectives To investigate the effect of hyperinsulinaemia on metabolism and vascular resistance of the isolated equine digit in a model of extracorporeal perfusion. Study design Randomised, controlled study with interventional group, with blinded evaluation of histology results. Method After exsanguination, equine digits (n = 11) and autologous blood were collected at an abattoir. One digit served as a hyperinsulinaemic pilot limb, 5 digits were assigned to the hyperinsulinaemic perfusion (IP) group and 5 to the control perfusion (CP) group. Digits were perfused for 10 h at a defined perfusion rate of 12 ml/min/kg. After the first hour of perfusion (equilibration period), insulin was added to the reservoir of the IP digits. Perfusion pressure, glucose consumption, lactate and lactate dehydrogenase were monitored. Vascular resistance was calculated as perfusion pressure (in millimetres of mercury) in relation to the flow rate (in millilitres per minute). After perfusion, histology samples of the dorsal hoof wall (haematoxylin & eosin or periodic acid-Schiff) were evaluated. Immunohistology with a polyclonal rabbit-derived anti-endothelin antibody was used for detection of ET-1. Results In the IP group, the mean insulin concentration in the plasma of the perfusate was 142 ± 81 μiu/ml, while insulin concentration was <3 μiu/ml in the CP group. Mean vascular resistance was significantly higher (P<0.01) in the IP group (2.04 ± 1.13 mmHg/ml/min) than in the CP group (1.31 ± 0.55 mmHg/ml/min). Histology of the IP group samples showed significantly more vessels with an open lumen, increased width of the secondary epidermal lamellae and formation of oedema. In the lamellar vessels (veins and arteries

  10. Cardiac beta-adrenoceptor blockade: the quest for selectivity.

    PubMed

    Barrett, A M

    1985-01-01

    In the search for improved drugs much attention has been focussed on the need for greater selectivity of action. Knowing that all drugs are poisons, the pharmacologist must attempt to define the required effect more narrowly but remain aware of potential unwanted effects. These may come as a result of the primary pharmacological effect or be due to other properties of the drug molecule manifesting themselves in clinical use. This paper illustrates the process of drug discovery and development with special reference to beta-adrenoceptor antagonists. Starting from the role of noradrenaline in sympathetic transmission, many compounds have been synthesized with therapeutic aims in mind. From a series of bronchodilators, dichloro-isoprenaline emerged which unexpectedly blocked stimulation of beta-receptors. This compound proved unsatisfactory leading to the introduction of the first clinically successful beta-blocker, pronethalol. Concern about potential carcinogenic effects led to its being replaced by propanolol. Failure to recognise the full range of clinical contra-indications resulted in propranolol causing severe cardio-vascular and bronchial adverse reactions. Soon it was recognized that propranolol was a powerful local anaesthetic potentially acting as a myocardial depressant. More serious was the recognition that in certain circumstances high levels of sympathetic tone were an adaptive response to pathophysiological change and that interruption by beta-blockade was inevitably serious for the patient. Attempts to identify the properties responsible for unwanted effects directed attention to comparison with non-local anaesthetic water soluble compounds still retaining beta-blocking activity. One such compound, practolol, also proved to exhibit a higher affinity for beta-receptors in the heart than elsewhere leading to the concept of cardioselective beta-blockade. The pharmacology of this agent is reviewed but it proved to have unacceptable side effects in

  11. Involvement of serotonin 2A receptor activation in modulating medial prefrontal cortex and amygdala neuronal activation during novelty-exposure.

    PubMed

    Hervig, Mona El-Sayed; Jensen, Nadja Cecilie Hvid; Rasmussen, Nadja Bredo; Rydbirk, Rasmus; Olesen, Mikkel Vestergaard; Hay-Schmidt, Anders; Pakkenberg, Bente; Aznar, Susana

    2017-03-02

    The medial prefrontal cortex (PFC) plays a major role in executive function by exerting a top-down control onto subcortical areas. Novelty-induced frontal cortex activation is 5-HT2A receptor (5-HT2AR) dependent. Here, we further investigated how blockade of 5-HT2ARs in mice exposed to a novel open-field arena affects medial PFC activation and basolateral amygdala (BLA) reactivity. We used c-Fos immunoreactivity (IR) as a marker of neuronal activation and stereological quantification for obtaining the total number of c-Fos-IR neurons as a measure of regional activation. We further examined the impact of 5-HT2AR blockade on the striatal-projecting BLA neurons. Systemic administration of ketanserin (0.5mg/kg) prior to novel open-field exposure resulted in reduced total numbers of c-Fos-IR cells in dorsomedial PFC areas and the BLA. Moreover, there was a positive correlation between the relative time spent in the centre of the open-field and BLA c-Fos-IR in the ketanserin-treated animals. Unilateral medial PFC lesions blocked this effect, ascertaining an involvement of this frontal cortex area. On the other hand, medial PFC lesioning exacerbated the more anxiogenic-like behaviour of the ketanserin-treated animals, upholding its involvement in modulating averseness. Ketanserin did not affect the number of activated striatal-projecting BLA neurons (measured by number of Cholera Toxin b (CTb) retrograde labelled neurons also being c-Fos-IR) following CTb injection in the ventral striatum. These results support a role of 5-HT2AR activation in modulating mPFC and BLA activation during exposure to a novel environment, which may be interrelated. Conversely, 5-HT2AR blockade does not seem to affect the amygdala-striatal projection.

  12. Myocardial ischemia-reperfusion enhances transcriptional expression of endothelin-1 and vasoconstrictor ETB receptors via the protein kinase MEK-ERK1/2 signaling pathway in rat

    PubMed Central

    Kruse, Lars Schack; Berchtold, Lukas Adrian; Grell, Anne-Sofie; Warfvinge, Karin; Edvinsson, Lars

    2017-01-01

    Background Coronary artery remodelling and vasospasm is a complication of acute myocardial ischemia and reperfusion. The underlying mechanisms are complex, but the vasoconstrictor peptide endothelin-1 is suggested to have an important role. This study aimed to determine whether the expression of endothelin-1 and its receptors are regulated in the myocardium and in coronary arteries after experimental ischemia-reperfusion. Furthermore, we evaluated whether treatment with a specific MEK1/2 inhibitor, U0126, modified the expression and function of these proteins. Methods and findings Sprague-Dawley rats were randomly divided into three groups: sham-operated, ischemia-reperfusion with vehicle treatment and ischemia-reperfusion with U0126 treatment. Ischemia was induced by ligating the left anterior descending coronary artery for 30 minutes followed by reperfusion. U0126 was administered before ischemia and repeated 6 hours after start of reperfusion. The contractile properties of isolated coronary arteries to endothelin-1 and sarafotoxin 6c were evaluated using wire-myography. The gene expression of endothelin-1 and endothelin receptors were measured using qPCR. Distribution and localization of proteins (pERK1/2, prepro-endothelin-1, endothelin-1, and endothelin ETA and ETB receptors) were analysed by Western blot and immunohistochemistry. We found that pERK1/2 was significantly augmented in the ischemic area 3 hours after ischemia-reperfusion; this correlated with increased ETB receptor and ET-1 gene expressions in ischemic myocardium and in coronary arteries. ETB receptor-mediated vasoconstriction was observed to be increased in coronary arteries 24 hours after ischemia-reperfusion. Treatment with U0126 reduced pERK1/2, expression of ET-1 and ETB receptor, and ETB receptor-mediated vasoconstriction. Conclusions These findings suggest that the MEK-ERK1/2 signaling pathway is important for regulating endothelin-1 and ETB receptors in myocardium and coronary arteries

  13. The 37kDa/67kDa Laminin Receptor acts as a receptor for Aβ42 internalization

    PubMed Central

    Da Costa Dias, Bianca; Jovanovic, Katarina; Gonsalves, Danielle; Moodley, Kiashanee; Reusch, Uwe; Knackmuss, Stefan; Weinberg, Marc S.; Little, Melvyn; Weiss, Stefan F. T.

    2014-01-01

    Neuronal loss is a major neuropathological hallmark of Alzheimer's disease (AD). The associations between soluble Aβ oligomers and cellular components cause this neurotoxicity. The 37 kDa/67 kDa laminin receptor (LRP/LR) has recently been implicated in Aβ pathogenesis. In this study the mechanism underlying the pathological role of LRP/LR was elucidated. Försters Resonance Energy Transfer (FRET) revealed that LRP/LR and Aβ form a biologically relevant interaction. The ability of LRP/LR to form stable associations with endogenously shed Aβ was confirmed by pull down assays and Aβ-ELISAs. Antibody blockade of this association significantly lowered Aβ42 induced apoptosis. Furthermore, antibody blockade and shRNA mediated downregulation of LRP/LR significantly hampered Aβ42 internalization. These results suggest that LRP/LR is a receptor for Aβ42 internalization, mediating its endocytosis and contributing to the cytotoxicity of the neuropeptide by facilitating intra-cellular Aβ42 accumulation. These findings recommend anti-LRP/LR specific antibodies and shRNAs as potential therapeutic tools for AD treatment. PMID:24990253

  14. Structure of the adenosine A(2A) receptor in complex with ZM241385 and the xanthines XAC and caffeine.

    PubMed

    Doré, Andrew S; Robertson, Nathan; Errey, James C; Ng, Irene; Hollenstein, Kaspar; Tehan, Ben; Hurrell, Edward; Bennett, Kirstie; Congreve, Miles; Magnani, Francesca; Tate, Christopher G; Weir, Malcolm; Marshall, Fiona H

    2011-09-07

    Methylxanthines, including caffeine and theophylline, are among the most widely consumed stimulant drugs in the world. These effects are mediated primarily via blockade of adenosine receptors. Xanthine analogs with improved properties have been developed as potential treatments for diseases such as Parkinson's disease. Here we report the structures of a thermostabilized adenosine A(2A) receptor in complex with the xanthines xanthine amine congener and caffeine, as well as the A(2A) selective inverse agonist ZM241385. The receptor is crystallized in the inactive state conformation as defined by the presence of a salt bridge known as the ionic lock. The complete third intracellular loop, responsible for G protein coupling, is visible consisting of extended helices 5 and 6. The structures provide new insight into the features that define the ligand binding pocket of the adenosine receptor for ligands of diverse chemotypes as well as the cytoplasmic regions that interact with signal transduction proteins.

  15. Edge-state blockade of transport in quantum dot arrays

    NASA Astrophysics Data System (ADS)

    Benito, Mónica; Niklas, Michael; Platero, Gloria; Kohler, Sigmund

    2016-03-01

    We propose a transport blockade mechanism in quantum dot arrays and conducting molecules based on an interplay of Coulomb repulsion and the formation of edge states. As a model we employ a dimer chain that exhibits a topological phase transition. The connection to a strongly biased electron source and drain enables transport. We show that the related emergence of edge states is manifest in the shot noise properties as it is accompanied by a crossover from bunched electron transport to a Poissonian process. For both regions we develop a scenario that can be captured by a rate equation. The resulting analytical expressions for the Fano factor agree well with the numerical solution of a full quantum master equation.

  16. Inelastic Photon Scattering via the Intracavity Rydberg Blockade

    NASA Astrophysics Data System (ADS)

    Grankin, A.; Brion, E.; Boddeda, R.; Ćuk, S.; Usmani, I.; Ourjoumtsev, A.; Grangier, P.

    2016-12-01

    Electromagnetically induced transparency (EIT) in a ladder system involving a Rydberg level is known to yield giant optical nonlinearities for the probe field, even in the few-photon regime. This enhancement is due to the strong dipole-dipole interactions between Rydberg atoms and the resulting excitation blockade phenomenon. In order to study such highly correlated media, ad hoc models or low-excitation assumptions are generally used to tackle their dynamical response to optical fields. Here, we study the behavior of a cavity Rydberg-EIT setup in the nonequilibrium quantum field formalism, and we obtain analytic expressions for elastic and inelastic components of the cavity transmission spectrum, valid up to higher excitation numbers than previously achieved. This allows us to identify and interpret a polaritonic resonance structure, to our knowledge unreported so far.

  17. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices

    NASA Astrophysics Data System (ADS)

    Lotkhov, Sergey V.

    2013-06-01

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ˜ 20 mK for films with sheet resistivities as high as ˜7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.

  18. Ultra-high-ohmic microstripline resistors for Coulomb blockade devices.

    PubMed

    Lotkhov, Sergey V

    2013-06-14

    In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ~ 20 mK for films with sheet resistivities as high as ~7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.

  19. Rescue of long-term memory after reconsolidation blockade

    PubMed Central

    Trent, Simon; Barnes, Philip; Hall, Jeremy; Thomas, Kerrie L.

    2015-01-01

    Memory reconsolidation is considered to be the process whereby stored memories become labile on recall, allowing updating. Blocking the restabilization of a memory during reconsolidation is held to result in a permanent amnesia. The targeted knockdown of either Zif268 or Arc levels in the brain, and inhibition of protein synthesis, after a brief recall results in a non-recoverable retrograde amnesia, known as reconsolidation blockade. These experimental manipulations are seen as key proof for the existence of reconsolidation. However, here we demonstrate that despite disrupting the molecular correlates of reconsolidation in the hippocampus, rodents are still able to recover contextual memories. Our results challenge the view that reconsolidation is a separate memory process and instead suggest that the molecular events activated initially at recall act to constrain premature extinction. PMID:26238574

  20. Sustained Neuromuscular Blockade after Vecuronium Use in a Premature Infant

    PubMed Central

    Sahni, Mitali; Richardson, C. Joan; Jain, Sunil K.

    2015-01-01

    Background Prolonged use of neuromuscular blocking agents (NMBAs) is very common in critically ill children both in pediatric and neonatal intensive care units. There are no guidelines available for use of NMBAs in children or neonates in the US, and the data for their safety in this age group is limited. Case Description Our case describes prolonged neuromuscular blockade following concurrent use of a NMBA along with aminoglycosides and steroids in the setting of renal failure in a premature infant. Conclusion Prolonged use of NMBAs in preterm infants should be avoided if possible or should be restricted to the shortest possible duration and the smallest possible physiologically effective dose. Concurrent use of NMBAs with aminoglycoside and steroids should be avoided, especially in the setting of renal failure. PMID:26495168

  1. Suppression of inflammatory events associated to intestinal ischemia-reperfusion by 5-HT1A blockade in mice.

    PubMed

    Bertoni, Simona; Arcaro, Valentina; Vivo, Valentina; Rapalli, Alberto; Tognolini, Massimiliano; Cantoni, Anna Maria; Saccani, Francesca; Flammini, Lisa; Domenichini, Giuseppe; Ballabeni, Vigilio; Barocelli, Elisabetta

    2014-03-01

    Intestinal ischemia and reperfusion (I/R) is a potentially life-threatening disease, ensuing from various clinical conditions. Experimentally, either protective or detrimental roles have been attributed to 5-HT in the functional and morphological injury caused by mesenteric I/R. Recently, we proved the involvement of 5-HT2A receptors in the intestinal dysmotility and leukocyte recruitment induced by 45min occlusion of the superior mesenteric artery (SMA) followed by 24h reperfusion in mice. Starting from these premises, the aim of our present work was to investigate the role played by endogenous 5-HT in the same experimental model where 45min SMA clamping was followed by 5h reflow. To this end, we first observed that ischemic preconditioning before I/R injury (IPC+I/R) reverted the increase in 5-HT tissue content and in inflammatory parameters induced by I/R in mice. Second, the effects produced by intravenous administration of 5-HT1A ligands (partial agonist buspirone 10mgkg(-1), antagonist WAY100135 0.5-5mgkg(-1)), 5-HT2A antagonist sarpogrelate (10mgkg(-1)), 5-HT3 antagonist alosetron (0.1mgkg(-1)), 5-HT4 antagonist GR125487 (5mgkg(-1)) and 5-HT re-uptake inhibitor fluoxetine (10mgkg(-1)) on I/R-induced inflammatory response were investigated in I/R mice and compared to those obtained in sham-operated animals (S). Our results confirmed the significant role played by 5-HT2A receptors not only in the late but also in the early I/R-induced microcirculatory dysfunction and showed that blockade of 5-HT1A receptors protected against the intestinal leukocyte recruitment, plasma extravasation and reactive oxygen species formation triggered by SMA occlusion and reflow. The ability of α7 nicotinic receptor (α7nAchR) antagonist methyllycaconitine (5mgkg(-1)) to counteract the beneficial action provided by buspirone on I/R-induced neutrophil infiltration suggests that the anti-inflammatory effect produced by 5-HT1A receptor antagonism could be partly ascribed to the

  2. Beta Blockade and Clinical Outcomes in Aneurysmal Subarachnoid Hemorrhage

    PubMed Central

    Chang, Melody M.; Raval, Ronak N.; Southerland, Jessie J.; Adewumi, Dare A.; Bahjri, Khaled A.; Samuel, Rajeev K.; Woods, Rafeek O.; Ajayi, Olaide O.; Lee, Bryan S.; Hsu, Frank P. K.; Applegate II, Richard L.; Dorotta, Ihab R.

    2016-01-01

    Background: Aneurysmal subarachnoid hemorrhages are frequently complicated by hypertension and neurogenic myocardial stunning. Beta blockers may be used for management of these complications. We sought to investigate sympathetic nervous system modulation by beta blockers and their effect on radiographic vasospasm, delayed cerebral infarction, discharge destination and death. Methods: Retrospective chart review of 218 adults admitted to the ICU between 8/2004 and 9/2010 was performed. Groups were identified relevant to beta blockade: 77 were never beta blocked (No/No), 123 received post-admission beta blockers (No/Yes), and 18 were continued on their home beta blockers (Yes/Yes). Records were analyzed for baseline characteristics and the development of vasospasm, delayed cerebral infarction, discharge destination and death, expressed as adjusted odds ratio. Results: Of the 218 patients 145 patients developed vasospasm, 47 consequently infarcted, and 53 died or required care in a long-term facility. When compared to No/No patients, No/Yes patients had significantly increased vasospasm (OR 2.11 (1.06-4.16)). However, these patients also had significantly fewer deaths or need for long term care (OR 0.17 (0.05-0.64)), with decreased tendency for infarcts (OR 0.70 (0.32-1.55)). When compared to No/No patients, Yes/Yes patients demonstrated a trend toward increased vasospasm (OR 1.61 (0.50-5.29)) that led to infarction (OR 1.51 (0.44-5.13)), but with decreased mortality or need for long term care in a facility (OR 0.13 (0.01-1.30)). Conclusion: Post-admission beta blockade in aneurysmal subarachnoid hemorrhage patients was associated with increased incidence of vasospasm. However, despite the increased occurrence of vasospasm, beta blockers were associated with improved discharge characteristics and fewer deaths. PMID:28217182

  3. Assessment of Methods for the Intracellular Blockade of GABAA Receptors

    PubMed Central

    Atherton, Laura A.; Burnell, Erica S.; Mellor, Jack R.

    2016-01-01

    Selective blockade of inhibitory synaptic transmission onto specific neurons is a useful tool for dissecting the excitatory and inhibitory synaptic components of ongoing network activity. To achieve this, intracellular recording with a patch solution capable of blocking GABAA receptors has advantages over other manipulations, such as pharmacological application of GABAergic antagonists or optogenetic inhibition of populations of interneurones, in that the majority of inhibitory transmission is unaffected and hence the remaining network activity preserved. Here, we assess three previously described methods to block inhibition: intracellular application of the molecules picrotoxin, 4,4’-dinitro-stilbene-2,2’-disulphonic acid (DNDS) and 4,4’-diisothiocyanostilbene-2,2’-disulphonic acid (DIDS). DNDS and picrotoxin were both found to be ineffective at blocking evoked, monosynaptic inhibitory postsynaptic currents (IPSCs) onto mouse CA1 pyramidal cells. An intracellular solution containing DIDS and caesium fluoride, but lacking nucleotides ATP and GTP, was effective at decreasing the amplitude of IPSCs. However, this effect was found to be independent of DIDS, and the absence of intracellular nucleotides, and was instead due to the presence of fluoride ions in this intracellular solution, which also blocked spontaneously occurring IPSCs during hippocampal sharp waves. Critically, intracellular fluoride ions also caused a decrease in both spontaneous and evoked excitatory synaptic currents and precluded the inclusion of nucleotides in the intracellular solution. Therefore, of the methods tested, only fluoride ions were effective for intracellular blockade of IPSCs but this approach has additional cellular effects reducing its selectivity and utility. PMID:27501143

  4. Defining Effective Combinations of Immune Checkpoint Blockade and Oncolytic Virotherapy

    PubMed Central

    Rojas, Juan J; Sampath, Padma; Hou, Weizhou; Thorne, Steve H

    2015-01-01

    Purpose Recent data from randomized clinical trials with oncolytic viral therapies and with cancer immunotherapies have finally recapitulated the promise these platforms demonstrated in pre-clinical models. Perhaps the greatest advance with oncolytic virotherapy has been the appreciation of the importance of activation of the immune response in therapeutic activity. Meanwhile, the understanding that blockade of immune checkpoints (with antibodies that block the binding of PD1 to PDL1 or CTLA4 to B7-2) is critical for an effective anti-tumor immune response has revitalized the field of immunotherapy. The combination of immune activation using an oncolytic virus and blockade of immune checkpoints is therefore a logical next step. Experimental Design Here we explore such combinations and demonstrate their potential to produce enhanced responses in mouse tumor models. Different combinations and regimens were explored in immunocompetent mouse models of renal and colorectal cancer. Bioluminescence imaging and immune assays were used to determine the mechanisms mediating synergistic or antagonistic combinations. Results Interaction between immune checkpoint inhibitors and oncolytic virotherapy was found to be complex, with correct selection of viral strain, antibody and timing of the combination being critical for synergistic effects. Indeed, some combinations produced antagonistic effects and loss of therapeutic activity. A period of oncolytic viral replication and directed targeting of the immune response against the tumor were required for the most beneficial effects, with CD8+ and NK, but not CD4+ cells mediating the effects. Conclusions These considerations will be critical in the design of the inevitable clinical translation of these combination approaches. PMID:26187615

  5. A pilot study on transient ischemic stroke induced with endothelin-1 in the rhesus monkeys

    PubMed Central

    Dai, PeiMin; Huang, Hui; Zhang, Lin; He, Jing; Zhao, XuDong; Yang, FuHan; Zhao, Ning; Yang, JianZhen; Ge, LongJiao; Lin, Yu; Yu, HuaLin; Wang, JianHong

    2017-01-01

    Endothelin-1 (ET-1), a vasoconstrictor, has recently been used to induce focal ischemia in rodents and marmoset monkeys. The rhesus monkey, however, has numerous advantages to the rodent and marmoset that make it a superior and irreplaceable animal model for studying stroke in the brain. In the present study, after mapping the preferred hand representation in two healthy male monkeys with intracortical micro-stimulation, ET-1 was microinjected into the contralateral motor cortex (M1) to its preferred hand. The monkeys had been trained in three manual dexterity tasks before the microinjection and were tested for these tasks following the ET-1 injection. Brain Magnetic Resonance Imaging scans were performed 1, 7, 14 and 28 days post ischemia. It was found that ET-1 impaired the manual dexterity of the monkeys in the vertical slot and rotating Brinkman board tasks 3–8 days after the injection. Brain imaging found that severe edema was present 7 days after the focal ischemia. This data suggest that ET-1 can induce transient ischemic stroke in rhesus monkey and that ET-1 induced focal ischemia in non-human primates is a potential model to study the mechanism of stroke and brain repair after stroke. PMID:28358140

  6. Regulation of the norepinephrine transporter by endothelins: a potential therapeutic target.

    PubMed

    Vatta, Marcelo S; Bianciotti, Liliana G; Guil, María J; Hope, Sandra I

    2015-01-01

    Neuronal norepinephrine (NE) uptake is a crucial step in noradrenergic neurotransmission that regulates NE concentration in the synaptic cleft. It is a key mechanism mediated by the NE transporter (NET) which takes the neurotransmitter into the presynaptic neuron terminal or the adrenal medulla chromaffin cell. The activity of NET is short and long terms modulated by phosphorylation mediated by protein kinases A, C, and G and calcium-calmodulin-dependent protein kinase, whereas the transporter availability at the cell surface is regulated by glycosylation. Several neuropeptides like angiotensins II, III, and 1-7, bradykinin, natriuretic peptides, as well as endothelins (ETs) regulate a wide variety of biological effects, including noradrenergic transmission and in particular neuronal NE uptake. Diverse reports, including studies from our laboratory, show that ETs differentially modulate the activity and expression of NET not only in normal conditions but also in diverse cardiovascular diseases such as congestive heart failure and hypertension. Current literature supports a key role for the interaction between ETs and NE in maintaining neurotransmission homeostasis and further suggests that this interaction may represent a potential therapeutic target for various diseases, particularly hypertension.

  7. Effect of endothelin-1 on calcium channel gating by agonists in vascular smooth muscle

    SciTech Connect

    Godfraind, T.; Mennig, D.; Morel, N.; Wibo, M.

    1989-01-01

    Rat isolated aorta was more sensitive to the contractile effect of endothelin-1 (ET-1) when the endothelium was removed. ET-1 was more potent on mesenteric resistance arteries than on aorta. A threshold concentration of ET-1 (100 pM) enhanced the contractile responses of aortic rings to Bay K 8644 and clonidine, especially in the absence of endothelium. Potentiation of clonidine-evoked contraction was accompanied by an enhancement of /sup 45/Ca influx and was abolished by nifedipine. These actions of ET-1 (100 pM) could not be attributed to a decrease in membrane potential or in cAMP levels. ET-1 (100 pM) decreased cGMP in intact aortic rings, which could contribute to its actions in the presence of endothelium. Removal of endothelium reduced cGMP levels and these were not further decreased by ET-1. Since ET-1 exerted a pronounced potentiating effect in the absence of endothelium, it is likely that ET-1 modulates calcium channels by an additional mechanism, unrelated to cyclic nucleotides.

  8. Endothelin-1 receptors in rat tissues: characterization by bosentan, ambrisentan and CI-1020.

    PubMed

    Yokoyama, Yoshinari; Osano, Ayaka; Hayashi, Hideki; Itoh, Kunihiko; Okura, Takashi; Deguchi, Yoshiharu; Ito, Yoshihiko; Yamada, Shizuo

    2014-01-01

    The present study aimed to characterize comparatively endothelin-1 (ET-1) receptors in rat tissues by radioligand binding assay using [(125)I]ET-1 and to examine receptor binding after oral administration of bosentan. Significant amount of specific [(125)I]ET-1 binding was detected in the lung, heart, kidney, bladder and cerebral cortex of rats. ET-1, bosentan, ambrisentan, and CI-1020 inhibited specific [(125)I]ET-1 binding in these tissues in a concentration-dependent manner. The Hill coefficients of each agent in the rat lung and cerebral cortex and those of bosentan and ET-1 in the heart, kidney and bladder were close to unity, while the Hill coefficients of ambrisentan and CI-1020 in the heart, kidney and bladder were less than one. The nonlinear least squares regression analysis revealed the presence of high- and low-affinity ET-1 receptor sites in these tissues for ambrisentan and CI-1020. Oral administration of bosentan caused a dose-dependent decrease in specific [(125)I]ET-1 binding in the rat lung, kidney and bladder, suggesting significant binding of the tissue ET-1 receptors in vivo. In conclusion, it has been shown that a significant amount of pharmacologically relevant ET-1 receptors may exist in rat tissues and that ET-1 receptor antagonists such as bosentan at pharmacological doses may exert some pharmacological effects by binding these ET-1 receptors.

  9. Endothelins are more sensitive than sarafotoxins to neutral endopeptidase: possible physiological significance.

    PubMed Central

    Skolovsky, M; Galron, R; Kloog, Y; Bdolah, A; Indig, F E; Blumberg, S; Fleminger, G

    1990-01-01

    Incubation of endothelins (ETs) with bovine kidney neutral endopeptidase (NEP) resulted in a selective two-step degradation with loss of biochemical activity. The Km of the enzyme indicated high-affinity binding, and hydrolysis was completely inhibited by phosphoramidon. The first step was nicking of the Ser5-Leu6 bond, followed by cleavage at the amino side of Ile19. The nicked peptide exhibited biochemical activities comparable to those of the intact peptide--i.e., binding to the ET receptor, induction of inositol phospholipid hydrolysis, and toxicity. The twice-cleaved product was inactive. The sarafotoxins (SRTXs) were more resistant than the ETs to NEP: for example, the half-time for ET-1 was approximately 1 hr, while it was approximately 4 hr for SRTX-b and even higher for SRTX-c. These in vitro findings may indicate a regulatory role of NEP (or similar enzymes) in the physiological inactivation of ETs. They might also help to explain why under certain physiological conditions ETs may be less toxic than SRTXs. Images PMID:2191299

  10. Endothelins are more sensitive than sarafotoxins to neutral endopeptidase: possible physiological significance.

    PubMed

    Skolovsky, M; Galron, R; Kloog, Y; Bdolah, A; Indig, F E; Blumberg, S; Fleminger, G

    1990-06-01

    Incubation of endothelins (ETs) with bovine kidney neutral endopeptidase (NEP) resulted in a selective two-step degradation with loss of biochemical activity. The Km of the enzyme indicated high-affinity binding, and hydrolysis was completely inhibited by phosphoramidon. The first step was nicking of the Ser5-Leu6 bond, followed by cleavage at the amino side of Ile19. The nicked peptide exhibited biochemical activities comparable to those of the intact peptide--i.e., binding to the ET receptor, induction of inositol phospholipid hydrolysis, and toxicity. The twice-cleaved product was inactive. The sarafotoxins (SRTXs) were more resistant than the ETs to NEP: for example, the half-time for ET-1 was approximately 1 hr, while it was approximately 4 hr for SRTX-b and even higher for SRTX-c. These in vitro findings may indicate a regulatory role of NEP (or similar enzymes) in the physiological inactivation of ETs. They might also help to explain why under certain physiological conditions ETs may be less toxic than SRTXs.

  11. Air Pollution-Induced Vascular Dysfunction: Potential Role of Endothelin-1 (ET-1) System.

    PubMed

    Finch, Jordan; Conklin, Daniel J

    2016-07-01

    Exposure to air pollution negatively impacts cardiovascular health. Studies show that increased exposure to a number of airborne pollutants increases the risk for cardiovascular disease progression, myocardial events, and cardiovascular mortality. A hypothesized mechanism linking air pollution and cardiovascular disease is the development of systemic inflammation and endothelium dysfunction, the latter of which can result from an imbalance of vasoactive factors within the vasculature. Endothelin-1 (ET-1) is a potent peptide vasoconstrictor that plays a significant role in regulating vascular homeostasis. It has been reported that the production and function of ET-1 and its receptors are upregulated in a number of disease states associated with endothelium dysfunction including hypertension and atherosclerosis. This mini-review surveys epidemiological and experimental air pollution studies focused on ET-1 dysregulation as a plausible mechanism underlying the development of cardiovascular disease. Although alterations in ET-1 system components are observed in some studies, there remains a need for future research to clarify whether these specific changes are compensatory or causally related to vascular injury and dysfunction. Moreover, further research may test the efficacy of selective ET-1 pharmacological interventions (e.g., ETA receptor inhibitors) to determine whether these treatments could impede the deleterious impact of air pollution exposure on cardiovascular health.

  12. Role of the endothelin system in sexual dimorphism in cardiovascular and renal diseases.

    PubMed

    Gohar, Eman Y; Giachini, Fernanda R; Pollock, David M; Tostes, Rita C

    2016-08-15

    Epidemiological studies of blood pressure in men and women and in experimental animal models point to substantial sex differences in the occurrence of arterial hypertension as well as in the various manifestations of arterial hypertension, including myocardial infarction, stroke, retinopathy, chronic kidney failure, as well as hypertension-associated diseases (e.g. diabetes mellitus). Increasing evidence demonstrates that the endothelin (ET) system is a major player in the genesis of sex differences in cardiovascular and renal physiology and diseases. Sex differences in the ET system have been described in the vasculature, heart and kidney of humans and experimental animals. In the current review, we briefly describe the role of the ET system in the cardiovascular and renal systems. We also update information on sex differences at different levels of the ET system including synthesis, circulating and tissue levels, receptors, signaling pathways, ET actions, and responses to antagonists in different organs that contribute to blood pressure regulation. Knowledge of the mechanisms underlying sex differences in arterial hypertension can impact therapeutic strategies. Sex-targeted and/or sex-tailored approaches may improve treatment of cardiovascular and renal diseases.

  13. Cytokine modulation by endothelin-1 and possible therapeutic implications in systemic sclerosis.

    PubMed

    Giordano, N; Papakostas, P; Pecetti, G; Nuti, R

    2011-01-01

    Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disorder characterized by a progressive fibrosis which involves skin and internal organs, caused by microvascular damage. The earliest clinical sign of the disease is Raynauds Phenomenon, a vasospastic response to cold or stress stimuli, followed by the skin and organ involvement over time. This kind of vascular manifestation originates from the microvascular structural alteration, characterized by an abnormal myocyte cell proliferation, intima cell proliferation and adventitia fibrosis. The microvascular damage seems to be the consequence of the autoimmune attack to the endothelium, followed by inflammatory cascade and massive deposition of collagen. From the beginning of the disorder, serum Endothelin-1 (ET- 1) is found in very high concentration: this protein, today, is considered one of the most important mediators of scleroderma vascular alterations. Furthermore, many recent studies have shown that ET-1 is involved in the inflammatory and fibrotic processes, increasing the concentration of pro-fibrotic and pro-inflammatory cytokines. The aim of this review is to clarify the ET-1 role in SSc, in particular the relationship between ET-1 and cytokine expression, adding another element to the understanding of scleroderma disease.

  14. A Complex Genomic Rearrangement Involving the Endothelin 3 Locus Causes Dermal Hyperpigmentation in the Chicken

    PubMed Central

    Dorshorst, Ben; Molin, Anna-Maja; Rubin, Carl-Johan; Johansson, Anna M.; Strömstedt, Lina; Pham, Manh-Hung; Chen, Chih-Feng; Hallböök, Finn; Ashwell, Chris; Andersson, Leif

    2011-01-01

    Dermal hyperpigmentation or Fibromelanosis (FM) is one of the few examples of skin pigmentation phenotypes in the chicken, where most other pigmentation variants influence feather color and patterning. The Silkie chicken is the most widespread and well-studied breed displaying this phenotype. The presence of the dominant FM allele results in extensive pigmentation of the dermal layer of skin and the majority of internal connective tissue. Here we identify the causal mutation of FM as an inverted duplication and junction of two genomic regions separated by more than 400 kb in wild-type individuals. One of these duplicated regions contains endothelin 3 (EDN3), a gene with a known role in promoting melanoblast proliferation. We show that EDN3 expression is increased in the developing Silkie embryo during the time in which melanoblasts are migrating, and elevated levels of expression are maintained in the adult skin tissue. We have examined four different chicken breeds from both Asia and Europe displaying dermal hyperpigmentation and conclude that the same structural variant underlies this phenotype in all chicken breeds. This complex genomic rearrangement causing a specific monogenic trait in the chicken illustrates how novel mutations with major phenotypic effects have been reused during breed formation in domestic animals. PMID:22216010

  15. A pilot study on transient ischemic stroke induced with endothelin-1 in the rhesus monkeys.

    PubMed

    Dai, PeiMin; Huang, Hui; Zhang, Lin; He, Jing; Zhao, XuDong; Yang, FuHan; Zhao, Ning; Yang, JianZhen; Ge, LongJiao; Lin, Yu; Yu, HuaLin; Wang, JianHong

    2017-03-30

    Endothelin-1 (ET-1), a vasoconstrictor, has recently been used to induce focal ischemia in rodents and marmoset monkeys. The rhesus monkey, however, has numerous advantages to the rodent and marmoset that make it a superior and irreplaceable animal model for studying stroke in the brain. In the present study, after mapping the preferred hand representation in two healthy male monkeys with intracortical micro-stimulation, ET-1 was microinjected into the contralateral motor cortex (M1) to its preferred hand. The monkeys had been trained in three manual dexterity tasks before the microinjection and were tested for these tasks following the ET-1 injection. Brain Magnetic Resonance Imaging scans were performed 1, 7, 14 and 28 days post ischemia. It was found that ET-1 impaired the manual dexterity of the monkeys in the vertical slot and rotating Brinkman board tasks 3-8 days after the injection. Brain imaging found that severe edema was present 7 days after the focal ischemia. This data suggest that ET-1 can induce transient ischemic stroke in rhesus monkey and that ET-1 induced focal ischemia in non-human primates is a potential model to study the mechanism of stroke and brain repair after stroke.

  16. Endothelin receptor-specific control of endoplasmic reticulum stress and apoptosis in the kidney

    PubMed Central

    De Miguel, Carmen; Hamrick, William C.; Hobbs, Janet L.; Pollock, David M.; Carmines, Pamela K.; Pollock, Jennifer S.

    2017-01-01

    Endothelin-1 (ET-1) promotes renal damage during cardiovascular disease; yet, the molecular mechanisms involved remain unknown. Endoplasmic reticulum (ER) stress, triggered by unfolded protein accumulation in the ER, contributes to apoptosis and organ injury. These studies aimed to determine whether the ET-1 system promotes renal ER stress development in response to tunicamycin. ETB deficient (ETB def) or transgenic control (TG-con) rats were used in the presence or absence of ETA receptor antagonism. Tunicamycin treatment similarly increased cortical ER stress markers in both rat genotypes; however, only ETB def rats showed a 14–24 fold increase from baseline for medullary GRP78, sXBP-1, and CHOP. Pre-treatment of TG-con rats with the ETA blocker ABT-627 for 1 week prior to tunicamycin injection significantly reduced the ER stress response in cortex and medulla, and also inhibited renal apoptosis. Pre-treatment with ABT-627 failed to decrease renal ER stress and apoptosis in ETB def rats. In conclusion, the ET-1 system is important for the development of tunicamycin-induced renal ER stress and apoptosis. ETA receptor activation induces renal ER stress genes and apoptosis, while functional activation of the ETB receptor has protective effects. These results highlight targeting the ETA receptor as a therapeutic approach against ER stress-induced kidney injury. PMID:28230089

  17. Endothelin-1 supports clonal derivation and expansion of cardiovascular progenitors derived from human embryonic stem cells.

    PubMed

    Soh, Boon-Seng; Ng, Shi-Yan; Wu, Hao; Buac, Kristina; Park, Joo-Hye C; Lian, Xiaojun; Xu, Jiejia; Foo, Kylie S; Felldin, Ulrika; He, Xiaobing; Nichane, Massimo; Yang, Henry; Bu, Lei; Li, Ronald A; Lim, Bing; Chien, Kenneth R

    2016-03-08

    Coronary arteriogenesis is a central step in cardiogenesis, requiring coordinated generation and integration of endothelial cell and vascular smooth muscle cells. At present, it is unclear whether the cell fate programme of cardiac progenitors to generate complex muscular or vascular structures is entirely cell autonomous. Here we demonstrate the intrinsic ability of vascular progenitors to develop and self-organize into cardiac tissues by clonally isolating and expanding second heart field cardiovascular progenitors using WNT3A and endothelin-1 (EDN1) human recombinant proteins. Progenitor clones undergo long-term expansion and differentiate primarily into endothelial and smooth muscle cell lineages in vitro, and contribute extensively to coronary-like vessels in vivo, forming a functional human-mouse chimeric circulatory system. Our study identifies EDN1 as a key factor towards the generation and clonal derivation of ISL1(+) vascular intermediates, and demonstrates the intrinsic cell-autonomous nature of these progenitors to differentiate and self-organize into functional vasculatures in vivo.

  18. Twisting integrin receptors increases endothelin-1 gene expression in endothelial cells

    NASA Technical Reports Server (NTRS)

    Chen, J.; Fabry, B.; Schiffrin, E. L.; Wang, N.; Ingber, D. E. (Principal Investigator)

    2001-01-01

    A magnetic twisting stimulator was developed based on the previously published technique of magnetic twisting cytometry. Using ligand-coated ferromagnetic microbeads, this device can apply mechanical stresses with varying amplitudes, duration, frequencies, and waveforms to specific cell surface receptors. Biochemical and biological responses of the cells to the mechanical stimulation can be assayed. Twisting integrin receptors with RGD (Arg-Gly-Asp)-containing peptide-coated beads increased endothelin-1 (ET-1) gene expression by >100%. In contrast, twisting scavenger receptors with acetylated low-density lipoprotein-coated beads or twisting HLA antigen with anti-HLA antibody-coated beads did not lead to alterations in ET-1 gene expression. In situ hybridization showed that the increase in ET-1 mRNA was localized in the cells that were stressed with the RGD-coated beads. Blocking stretch-activated ion channels with gadolinium, chelating Ca2+ with EGTA, or inhibiting tyrosine phosphorylation with genistein abolished twist-induced ET-1 mRNA elevation. Abolishing cytoskeletal tension with an inhibitor of the myosin ATPase, with an inhibitor of myosin light chain kinase, or with an actin microfilament disrupter blocked twisted-induced increases in ET-1 expression. Our results are consistent with the hypothesis that the molecular structural linkage of integrin-cytoskeleton is an important pathway for stress-induced ET-1 gene expression.

  19. Alzheimer's disease beta-amyloid peptide is increased in mice deficient in endothelin-converting enzyme.

    PubMed

    Eckman, Elizabeth A; Watson, Mona; Marlow, Laura; Sambamurti, Kumar; Eckman, Christopher B

    2003-01-24

    The abnormal accumulation of beta-amyloid (Abeta) in the brain is an early and invariant feature in Alzheimer's disease (AD) and is believed to play a pivotal role in the etiology and pathogenesis of the disease. As such, a major focus of AD research has been the elucidation of the mechanisms responsible for the generation of Abeta. As with any peptide, however, the degree of Abeta accumulation is dependent not only on its production but also on its removal. In cell-based and in vitro models we have previously characterized endothelin-converting enzyme-1 (ECE-1) as an Abeta-degrading enzyme that appears to act intracellularly, thus limiting the amount of Abeta available for secretion. To determine the physiological significance of this activity, we analyzed Abeta levels in the brains of mice deficient for ECE-1 and a closely related enzyme, ECE-2. Significant increases in the levels of both Abeta40 and Abeta42 were found in the brains of these animals when compared with age-matched littermate controls. The increase in Abeta levels in the ECE-deficient mice provides the first direct evidence for a physiological role for both ECE-1 and ECE-2 in limiting Abeta accumulation in the brain and also provides further insight into the factors involved in Abeta clearance in vivo.

  20. Endothelin- and oxytocin-induced calcium signaling in cultured human myometrial cells.

    PubMed Central

    Maher, E; Bardequez, A; Gardner, J P; Goldsmith, L; Weiss, G; Mascarina, M; Aviv, A

    1991-01-01

    The demonstration that endothelin (ET) induces rat uterine contraction, coupled with the observation that ET is present in human amniotic fluid, suggests that the myometrium may be an important target organ for this hormone. We show that in quiescent human myometrial cells ET produced a dose-dependent increase in cytosolic free Ca2+ (Cai2+), which was markedly attenuated when the cells were studied in Ca2(+)-free media. Preincubation with nicardipine, diltiazem, or verapamil reduced the ET-evoked Cai2+ transient by 30, 40, and 65%, respectively. The presence of voltage sensitive Ca2+ channels was demonstrated by Mn2+ quenching of fura-2. Activation of the Na+/H+ antiport could not be demonstrated with ET stimulation. In nonquiescent cells, the ET-evoked Cai2+ transient was significantly reduced, while the response to oxytocin was retained. This is at least partially explained by a reduction in Bmax (maximal binding capacity) for ET (mean +/- SEM) from 3,506 +/- 268 binding sites/cell in quiescent cells to 2,411 +/- 300 binding sites/cell, as well as 72% increase in Kd (equilibrium dissociation constant), in the nonquiescent cells. We conclude that, in human myometrial cells, ET and oxytocin modulate Cai2+ through independent receptors and propose that ET, like oxytocin, is an important endogenous modulator of uterine contractility. Images PMID:1849147

  1. Endothelin-3 stimulates cell adhesion and cooperates with β1-integrins during enteric nervous system ontogenesis

    PubMed Central

    Gazquez, Elodie; Watanabe, Yuli; Broders-Bondon, Florence; Paul-Gilloteaux, Perrine; Heysch, Julie; Baral, Viviane; Bondurand, Nadège; Dufour, Sylvie

    2016-01-01

    Endothelin-3 (EDN3) and β1-integrins are required for the colonization of the embryonic gut by enteric neural crest cells (ENCCs) to form the enteric nervous system (ENS). β1-integrin-null ENCCs exhibit migratory defects in a region of the gut enriched in EDN3 and in specific extracellular matrix (ECM) proteins. We investigated the putative role of EDN3 on ENCC adhesion properties and its functional interaction with β1-integrins during ENS development. We show that EDN3 stimulates ENCC adhesion to various ECM components in vitro. It induces rapid changes in ENCC shape and protrusion dynamics favouring sustained growth and stabilization of lamellipodia, a process coincident with the increase in the number of focal adhesions and activated β1-integrins. In vivo studies and ex-vivo live imaging revealed that double mutants for Itgb1 and Edn3 displayed a more severe enteric phenotype than either of the single mutants demonstrated by alteration of the ENS network due to severe migratory defects of mutant ENCCs taking place early during the ENS development. Altogether, our results highlight the interplay between the EDN3 and β1-integrin signalling pathways during ENS ontogenesis and the role of EDN3 in ENCC adhesion. PMID:27905407

  2. Endothelin-Converting Enzymes and Related Metalloproteases in Alzheimer’s Disease

    PubMed Central

    Pacheco-Quinto, Javier; Herdt, Aimee; Eckman, Christopher B.; Eckman, Elizabeth A.

    2013-01-01

    The efficient clearance of amyloid β (Aβ) is essential to modulate levels of the peptide in the brain and to prevent it from accumulating in senile plaques, a hallmark of AD pathology. We and others have shown that failure in Aβ catabolism can produce elevations in Aβ concentration similar to those observed in familial forms of Alzheimer’s disease (AD). Based on the available evidence, it remains plausible that in late-onset AD, disturbances in the activity of Aβ degrading enzymes could induce Aβ accumulation, and that this increase could result in AD pathology. The following review presents a historical perspective of the parallel discovery of three vasopeptidases, neprilysin (NEP) and endothelin-converting enzymes-1 and -2 (ECE-1 and ECE-2), as important Aβ degrading enzymes. The recognition of the role of these vasopeptidases in Aβ degradation, beyond bringing to light a possible explanation of how cardiovascular risk factors may influence AD risk, highlights a possible risk of the use of inhibitors of these enzymes for other clinical indications such as hypertension. We will discuss in detail the experiments conducted to assess the impact of vasopeptidase deficiency (through pharmacological inhibition or genetic mutation) on Aβ accumulation, as well as the cooperative effect of multiple Aβ degrading enzymes to regulate concentration of the peptide at multiple sites, both intracellular and extracellular, throughout the brain. PMID:22903130

  3. Identification and developmental analysis of endothelin receptor type-A expressing cells in the mouse kidney.

    PubMed

    Kitazawa, Taro; Sato, Takahiro; Nishiyama, Koichi; Asai, Rieko; Arima, Yuichiro; Uchijima, Yasunobu; Kurihara, Yukiko; Kurihara, Hiroki

    2011-10-01

    The endothelin (Edn) system plays pleiotropic roles in renal function and various disease processes through two distinct G protein-coupled receptors, Edn receptors type-A (Ednra) and type-B (Ednrb). However, difficulties in the accurate identification of receptor-expressing cells in situ have made it difficult to dissect their diverse action in renal (patho)physiology. We have recently established mouse lines in which lacZ and EGFP are 'knocked-in' to the Ednra locus to faithfully mark Ednra-expressing cells. Here we analyzed these mice for their expression in the kidney to characterize Ednra-expressing cells. Ednra expression was first observed in undifferentiated mesenchymal cells around the ureteric bud at E12.5. Thereafter, Ednra expression was widely observed in vascular smooth muscle cells, JG cells and mesenchymal cells in the interstitium. After growth, the expression became confined to vascular smooth muscle cells, pericytes and renin-producing JG cells. By contrast, most cells in the nephron and vascular endothelial cells did not express Ednra. These results indicate that Ednra expression may be linked with non-epithelial fate determination and differentiation of metanephric mesenchyme. Ednra-lacZ/EGFP knock-in mice may serve as a useful tool in studies on renal function and pathophysiology of various renal diseases.

  4. Osmolar regulation of endothelin-1 production by rat inner medullary collecting duct.

    PubMed Central

    Kohan, D E; Padilla, E

    1993-01-01

    Recent evidence has implicated endothelin-1 (ET-1) as an autocrine inhibitor of inner medullary collecting duct (IMCD) sodium and water transport. The regulators of IMCD ET-1 production are, however, largely unknown. Because of the unique hypertonic environment of the IMCD, the effect of varying extracellular tonicity on IMCD ET-1 production was evaluated. Increasing media osmolality from 300 to 450 mosmol with NaCl or mannitol but not urea caused a marked dose- and time-dependent reduction in ET-1 release by and ET-1 mRNA in cultured rat IMCD cells. In contrast, increasing osmolality had no effect on ET-1 production by rat endothelial or mesangial cells. To see if ET-1 varies in a similar manner in vivo, ET-1 production was assessed in volume expanded (lower medullary tonicity) or volume depleted (high medullary tonicity) rats. Urinary ET-1 excretion and inner medulla ET-1 mRNA were significantly reduced in volume depleted as compared to volume expanded animals. These results indicate that extracellular sodium concentration inhibits ET-1 production specifically in IMCD cells. We speculate that extracellular sodium concentration, via regulation of ET-1 production, provides a link between volume status and IMCD sodium and water reabsorption. PMID:8450052

  5. Expression of endothelin-1 gene and protein in human granulosa cells

    SciTech Connect

    Magini, A.; Granchi, S.; Susini, T.

    1996-04-01

    Previous studies in animal models indicated an autocrine/paracrine action of endothelin-1 (ET-1) in the ovary. We now report evidence on the presence of ET-1 in human ovary during reproductive life. Immunohistochemical and in situ hybridization studies demonstrated a positive signal into cytoplasm of granulosa cells (GC) of follicles at different growth stages. The concentration of ET-1-like immunoreactivity (ET-1-Li) was also measured by a specific RIA in human follicular fluid (FF). FF samples were obtained from women in an in vitro fertilization program undergoing gonadotropin stimulation (group A; n = 24) or no treatment (group B; n = 7). The mean ({+-}SD) ET-1-LI FF level in group A (4.85 {+-} 2.06 pg/mL) was significantly higher than that in group B (1.29 {+-} 0.43 pg/mL; P < 0.01), whereas the corresponding mean plasma levels were not significantly different and were not correlated to respective FF values. Our results indicate for the first time the presence of ET-1 and its messenger ribonucleic acid in the GC of the human ovary. The higher ET-1-LI levels found in the FF from women undergoing gonadotropin treatment suggest a modulation by gonadotropins and/or ovarian steroids of ET-1 production by GC. 19 refs., 4 figs., 1 tab.

  6. Potentiation of the time-dependent, antidepressant-induced changes in the agonistic behaviour of resident rats by the 5-HT1A receptor antagonist, WAY-100635.

    PubMed

    Mitchell, P J; Redfern, P H

    1997-11-01

    Acute and chronic antidepressant drug treatments respectively decrease and increase the aggressive behaviour of resident rats during encounters with unfamiliar conspecifics. We have now examined the effect of the 5-hydroxytryptamine1A receptor antagonist, WAY-100635, on fluoxetine-, paroxetine- or venlafaxine-induced changes in aggression. WAY-100635 (0.1 mg/kg), which did not modify behaviour when given alone, potentiated the venlafaxine (5.54 mg/kg)-induced reduction in aggression after acute treatment and, during chronic treatment, accelerated the fluoxetine (0.34 mg/kg/day)-induced increase in aggression, from day 5 to day 2. A similar change in time course was seen with paroxetine (0.33 mg/kg/day), although the increase in aggression was smaller. Venlafaxine (5.54 mg/kg/day, alone or co-administered with WAY-100635) increased aggression by day 2. During chronic treatment, therefore, venlafaxine, at the dose used, had a more rapid onset of action than either fluoxetine or paroxetine, whereas the fluoxetine- and paroxetine-, but not the venlafaxine-, induced increase in aggression was accelerated by WAY-100635. These studies further support the hypothesis that selective blockade of the 5-hydroxytryptamine1A receptor augments the effects of antidepressant drugs in an animal model predictive of antidepressant activity, presumably by concomitant blockade of the somatodendritic 5-hydroxytryptamine1A autoreceptor-mediated negative feedback system of serotonergic neurones.

  7. 5-HT(1A) receptors and memory.

    PubMed

    Meneses, Alfredo; Perez-Garcia, Georgina

    2007-01-01

    The study of 5-hydroxytryptamine (5-HT) systems has benefited from the identification, classification and cloning of multiple 5-HT receptors (5-HT(1)-5-HT(7)). Increasing evidence suggests that 5-HT pathways, reuptake site/transporter complex and 5-HT receptors represent a strategic distribution for learning and memory. A key question still remaining is whether 5-HT markers (e.g., receptors) are directly or indirectly contributing to the physiological and pharmacological basis of memory and its pathogenesis or, rather, if they represent protective or adaptable mechanisms (at least in initial stages). In the current paper, the major aim is to revise recent advances regarding mammalian 5-HT(1A) receptors in light of their physiological, pathophysiological and therapeutic implications in memory. An attempt is made to identify and discuss sources of discrepancies by employing an analytic approach to examine the nature and degree of difficulty of behavioral tasks used, as well as implicating other factors (for example, brain areas, training time or duration, and drug administration) which might offer new insights into the understanding and interpretation of these data. In this context, 8-OH-DPAT deserves special attention since for many years it has been the more selective 5-HT drug and, hence, more frequently used. As 5-HT(1A) receptors are key components of serotonergic signaling, investigation of their memory mechanisms and action sites and the conditions under which they might operate, could yield valuable insights. Moreover, selective drugs with agonists, neutral antagonists or inverse agonist properties for 5-HT(1A) (and 5-HT(7)) receptors may constitute a new therapeutic opportunity for learning and memory disorders.

  8. Room temperature Coulomb blockade mediated field emission via self-assembled gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Fang, Jingyue; Chang, Shengli; Qin, Shiqiao; Zhang, Xueao; Xu, Hui

    2017-02-01

    Coulomb blockade mediated field-emission current was observed in single-electron tunneling devices based on self-assembled gold nanoparticles at 300 K. According to Raichev's theoretical model, by fixing a proper geometric distribution of source, island and drain, the transfer characteristics can be well explained through a combination of Coulomb blockade and field emission. Coulomb blockade and field emission alternately happen in our self-assembled devices. The Coulomb island size derived from the experimental data is in good agreement with the average size of the gold nanoparticles used in the device. The integrated tunneling can be adjusted via a gate electrode.

  9. Involvement of presynaptic voltage-dependent Kv3 channel in endothelin-1-induced inhibition of noradrenaline release from rat gastric sympathetic nerves.

    PubMed

    Nakamura, Kumiko; Shimizu, Takahiro; Tanaka, Kenjiro; Taniuchi, Keisuke; Yokotani, Kunihiko

    2012-11-05

    We previously reported that two types of K(+) channels, the BK type Ca(2+)-activated K(+) channel coupled with phospholipase C (PLC) and the voltage-dependent K(+) channel (Kv channel), are, respectively, involved in the prostanoid TP receptor- and muscarinic M(2) receptor-mediated inhibition of noradrenaline (NA) release from rat gastric sympathetic nerves. In the present study, therefore, we examined whether these K(+) channels are involved in endothelin-1-induced inhibition of NA release, using an isolated, vascularly perfused rat stomach. The gastric sympathetic postganglionic nerves around the left gastric artery were electrically stimulated twice at 2.5 Hz for 1 min, and endothelin-1 was added during the second stimulation. Endothelin-1 (1, 2 and 10 nM) dose-dependently inhibited gastric NA release. Endothelin-1 (2 nM)-induced inhibition of NA release was neither attenuated by PLC inhibitors [U-73122 (3 μM) and ET-18-OCH(3) (3 μM)] nor by Ca(2+)-activated K(+) channel blockers [charybdotoxin (0.1 μM) (a blocker of BK type K(+) channel) and apamin (0.3 μM) (a blocker of SK type K(+) channel)]. The endothelin-1-induced inhibitory response was also not attenuated by α-dendrotoxin (0.1 μM) (a selective inhibitor of Kv1 channel), but abolished by 4-aminopyridine (20 μM) (a selectively inhibitory dose for Kv3 channel). These results suggest the involvement of a voltage-dependent Kv3 channel in the endothelin-1-induced inhibition of NA release from the gastric sympathetic nerves in rats.

  10. Effects of endothelin-1 on the membrane potential and slow waves in circular smooth muscle of rat gastric antrum.

    PubMed

    Imaeda, Kenro; Kato, Takashi; Okayama, Naotsuka; Imai, Seiji; Sasaki, Makoto; Kataoka, Hiromi; Nakazawa, Takahiro; Ohara, Hirotaka; Kito, Yoshihiko; Itoh, Makoto

    2004-10-01

    Electrophysiological effects of endothelin-1 (ET-1) on circular smooth muscle of rat gastric antrum were investigated by using intracellular membrane potential recording techniques. ET-1 (10 nM) caused an initial hyperpolarization of the membrane which was followed by a sustained depolarization. ET-1 also increased the frequency but not the amplitude of slow waves. In the presence of the endothelin type A (ETA) receptor antagonist, BQ123 (1 microM), ET-1 (10 nM) depolarized the membrane and increased the frequency of slow waves, but without the initial hyperpolarization. The selective endothelin type B (ETB) receptor agonist, sarafotoxin S6c (10 nM), also depolarized the membrane and increased the frequency of slow waves. In the presence of the ETB receptor antagonist, BQ788 (1 microM), ET-1 (10 nM) hyperpolarized the membrane. However, in the presence of BQ788, ET-1 caused neither the depolarization nor the increase in the frequency of the slow waves. The ET-1-induced hyperpolarization was completely abolished by apamin (0.1 microM). In the presence of apamin, ET-1 depolarized the membrane and increased the frequency of slow waves. The ET-1-induced depolarization was significantly attenuated by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS, 0.3 mM). The increase of the frequency by ET-1 was observed both in the presence and absence of DIDS. These results suggest that, ET-1 hyperpolarizes the membrane by the activation of Ca2+-activated K+ channels via ETA receptors, and depolarizes the membrane by the activation of Ca2+-activated Cl- channels via ETB receptors. ET-1 also appears to increase the frequency of slow waves via ETB receptors, however this mechanism would seem to be independent of membrane depolarization.

  11. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

    SciTech Connect

    Ostrow, Lyle W.; Suchyna, Thomas M.; Sachs, Frederick

    2011-06-24

    Highlights: {yields} Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. {yields} Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca{sup 2+} permeant SACs. {yields} The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. {yields} Stretch-induced ET-1 production depends on a calcium influx. {yields} SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch (<20%) of a rubber substrate increased ET-1 secretion, and 4 {mu}M GsMTx-4 (a specific inhibitor of SACs) inhibited secretion by 30%. GsMTx-4 did not alter basal ET-1 levels in the absence of stretch. Decreasing the calcium influx by lowering extracellular calcium also inhibited stretch-induced ET-1 secretion without effecting ET-1 secretion in unstretched controls. Furthermore, inhibiting SACs with the less specific inhibitor streptomycin also inhibited stretch-induced ET-1 secretion. The data can be explained with a simple model in which ET-1 secretion depends on an internal Ca{sup 2+} threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

  12. Electroporation-aided DNA immunization generates polyclonal antibodies against the native conformation of human endothelin B receptor.

    PubMed

    Allard, Bertrand; Priam, Fabienne; Deshayes, Frédérique; Ducancel, Frédéric; Boquet, Didier; Wijkhuisen, Anne; Couraud, Jean-Yves

    2011-09-01

    Endothelin B receptor (ET(B)R) is a G protein-coupled receptor (GPCR) specific for endothelin peptides (including endothelin-1, ET1), which mediates a variety of key physiological functions in normal tissues, such as modulation of vasomotor tone, tissue differentiation, or cell proliferation. Moreover, ET(B)R, overexpressed in various cancer cells including melanoma, has been implicated in the growth and progression of tumors, as well as in controlling T cell homing to tumors. To gather information on receptor structure and function, antibodies are generally considered choice molecular probes, but generation of such reagents against the native conformation of GPCRs is a real technical challenge. Here, we show that electroporation-aided genetic immunization, coupled to cardiotoxin pretreatment, is a simple and very efficient method to raise large amounts of polyclonal antibodies highly specific for native human ET(B)R (hET(B)R), as assessed by both flow cytometry analysis of different stably transfected cell lines and a new and rapid cell-based enzyme-linked immunosorbent assay that we also describe. The antibodies recognized two major epitopes on hET(B)R, mapped within the N-terminal extracellular domain. They were used to reveal hET(B)R on membranes of three different human melanoma cell lines, by flow cytometry and confocal microscopy, a method that we show is more relevant than mRNA polymerase chain reaction in assessing receptor expression. In addition, ET-1 partially competed with antibodies for receptor binding. The strategy described here, thus, efficiently generated new immunological tools to further analyze the role of ET(B)R under both normal and pathological conditions, including cancers. Above all, it can now be used to raise monoclonal antibodies against hET(B)R and, more generally, against GPCRs that constitute, by far, the largest reservoir of potential pharmacological targets.

  13. Endothelin receptor antagonists improve exercise tolerance and oxygen saturations in patients with Eisenmenger syndrome and congenital heart defects.

    PubMed

    Mehta, Puja K; Simpson, Leo; Lee, Eva K; Lyle, Teresa A; McConnell, Michael E; Book, Wendy M

    2008-01-01

    Patients with Eisenmenger syndrome experience substantial morbidity and decreased survival rates. In advanced cases, lung transplantation with cardiac repair or heart-lung transplantation is often the only option. The efficacy of endothelin receptor antagonists in Eisenmenger syndrome, which has similar pathophysiology to idiopathic pulmonary hypertension, remains unknown.We retrospectively studied adults with congenital heart disease and Eisenmenger syndrome who were treated with endothelin receptor antagonists. Analysis included chart reviews of clinical evaluations, oxygen saturation levels, functional class, 6-minute walk distances, and pulmonary artery pressures. In the 24 patients studied, Eisenmenger syndrome was caused by ventricular septal defect (6 patients), atrial septal defect (5), atrioventricular canal defect (3), complex congenital heart disease (9), and patent ductus arteriosus (1).Eisenmenger syndrome was treated with bosentan (21 patients) and sitaxsentan (3 patients). On average, therapy lasted 19 +/- 12 months. Subsequently, mean 6-minute walk distances improved from 226 +/- 159 m to 351 +/- 113 m (P = 0.004), and World Health Organization functional class improved > or =1 grade (P < 0.0001). Oxygen saturations increased on therapy from 80.5% to 87% (P < 0.0001). Pulmonary arterial systolic pressures decreased from 97 +/- 21 mmHg to 78 +/- 27 mmHg, and mean pressures from 59 +/- 16 mmHg to 47 +/- 17 mmHg (both P < 0.0001). Neither major complications from therapy nor changes in pulmonary capillary wedge pressure occurred.Endothelin receptor antagonists may play an important role in improving 6-minute walk distance, oxygen saturation, pulmonary artery pressures, and symptoms in adults who have congenital heart defects and Eisenmenger syndrome.

  14. PD-1 Blockade in Tumors with Mismatch-Repair Deficiency

    PubMed Central

    Le, D.T.; Uram, J.N.; Wang, H.; Bartlett, B.R.; Kemberling, H.; Eyring, A.D.; Skora, A.D.; Luber, B.S.; Azad, N.S.; Laheru, D.; Biedrzycki, B.; Donehower, R.C.; Zaheer, A.; Fisher, G.A.; Crocenzi, T.S.; Lee, J.J.; Duffy, S.M.; Goldberg, R.M.; de la Chapelle, A.; Koshiji, M.; Bhaijee, F.; Huebner, T.; Hruban, R.H.; Wood, L.D.; Cuka, N.; Pardoll, D.M.; Papadopoulos, N.; Kinzler, K.W.; Zhou, S.; Cornish, T.C.; Taube, J.M.; Anders, R.A.; Eshleman, J.R.; Vogelstein, B.; Diaz, L.A.

    2015-01-01

    BACKGROUND Somatic mutations have the potential to encode “non-self” immunogenic antigens. We hypothesized that tumors with a large number of somatic mutations due to mismatch-repair defects may be susceptible to immune checkpoint blockade. METHODS We conducted a phase 2 study to evaluate the clinical activity of pembrolizumab, an anti–programmed death 1 immune checkpoint inhibitor, in 41 patients with progressive metastatic carcinoma with or without mismatch-repair deficiency. Pembrolizumab was administered intravenously at a dose of 10 mg per kilogram of body weight every 14 days in patients with mismatch repair–deficient colorectal cancers, patients with mismatch repair–proficient colorectal cancers, and patients with mismatch repair–deficient cancers that were not colorectal. The coprimary end points were the immune-related objective response rate and the 20-week immune-related progression-free survival rate. RESULTS The immune-related objective response rate and immune-related progression-free survival rate were 40% (4 of 10 patients) and 78% (7 of 9 patients), respectively, for mismatch repair–deficient colorectal cancers and 0% (0 of 18 patients) and 11% (2 of 18 patients) for mismatch repair–proficient colorectal cancers. The median progression-free survival and overall survival were not reached in the cohort with mismatch repair–deficient colorectal cancer but were 2.2 and 5.0 months, respectively, in the cohort with mismatch repair–proficient colorectal cancer (hazard ratio for disease progression or death, 0.10 [P<0.001], and hazard ratio for death, 0.22 [P = 0.05]). Patients with mismatch repair–deficient noncolorectal cancer had responses similar to those of patients with mismatch repair–deficient colorectal cancer (immune-related objective response rate, 71% [5 of 7 patients]; immune-related progression-free survival rate, 67% [4 of 6 patients]). Whole-exome sequencing revealed a mean of 1782 somatic mutations per tumor in

  15. Induced ion currents and the endothelin pathway as targets for anti-arrhythmic agents.

    PubMed

    Dai, De-Zai; Dai, Yin

    2008-09-01

    The development of novel anti-arrhythmic drugs is necessary, specifically agents that do not cause torsades de pointes (Tdp). Ion channelopathy that is involved in mechanisms underlying sudden cardiac death (SCD) includes both ion channels in the membrane, and the calcium-releasing channels and the calcium uptake process in the sarcoplasmic reticulum. Advances in the understanding of abnormalities of ion channels in the myocardium caused by congenital defects or by a failing heart and cardiomyopathy offer further insights into the relationship between channelopathy and SCD. Enhanced L-type Ca2+ current (ICa.L) activity has been detected in the hearts of patients with a mutation of the Cav1.2 gene; these patients exhibit a high risk of SCD. Rats with thyroxin-induced cardiomyopathy demonstrate an increase in ICa.L activity that is responsible for exacerbated ventricular fibrillation (VF). This is suppressed by propranolol or CPU-86017, a class III anti-arrhythmic agent with potent antioxidant activity. Interestingly, an increase in rapidly (IKr) and slowly (IKs) activating delayed rectifying K+ currents is caused by gain-of-function mutations of the KCNH2 and KCNQ1 genes, respectively, in patients with short QT syndrome (SQT). Increased IKr and IKs, which are associated with exacerbated VF, are also found in models of thyroxin-induced cardiomyopathy and are suppressed by CPU-86017. ICa.L, IKr and IKs can also be induced in cardiomyocytes when incubated with isoproterenol. A reversal of upstream lesions by an endothelin receptor antagonist CPU-0213 provides suppression of ventricular tachyarrhythmias and upregulates FK506 binding protein 12.6. CPU-86017 and its chiral isomer SR-CPU-86017 relieve upstream lesions, with mild suppression of IKr and moderate suppression of IKs and ICa.L. These agents may be promising as anti-arrhythmic agents that produce less Tdp tachyarrhythmias.

  16. Oestradiol ameliorates monocrotaline pulmonary hypertension via NO, prostacyclin and endothelin-1 pathways.

    PubMed

    Yuan, Ping; Wu, Wen-Hui; Gao, Lan; Zheng, Ze-Qi; Liu, Dong; Mei, Han-Ying; Zhang, Zhuo-Li; Jing, Zhi-Cheng

    2013-05-01

    Pulmonary hypertension continues to be a serious clinical problem with high mortality. As oestrogen is a potential vasodilator of the pulmonary circulation, this study examined the mechanisms by which 17β-oestradiol improves monocrotaline (MCT)-induced pulmonary hypertension. Female Sprague-Dawley rats underwent bilateral ovariectomy or sham operations. The rats received MCT (50 mg·kg(-1)) and were treated with 17β-oestradiol (1 mg·kg(-1) per day) for either 5 weeks or only from week 4 to week 5. Plasma 17β-oestradiol concentrations were decreased in sham-operated, MCT-treated rats when compared with sham-operated rats (17.7 ± 4.7 versus 50.3 ± 15.4 pg·mL(-1); p=0.029). The 17β-oestradiol anabolic enzyme cytochrome P450 (CYP)-19 was decreased by MCT treatment, while the catabolic enzymes CYP-1A1 and -1B1 were increased. Ovariectomised and MCT-treated rats had more severe pulmonary hypertension. 17β-oestradiol suppressed pulmonary arterial smooth muscle cell proliferation and macrophage infiltration, and enhanced apoptosis by increasing nitric oxide (NO) and prostacyclin (prostaglandin (PG)I2) levels and reducing endothelin (ET)-1 levels. Phosphoinositide-3-kinase (PI3K) and Akt phosphorylations were markedly increased, but were inhibited by 17β-oestradiol treatment in rats with pulmonary hypertension. Oestrogen deficiency may aggravate development of pulmonary hypertension. 17β-oestradiol improved pulmonary hypertension via activation of the PI3K/Akt pathway to regulate NO, PGI2 and ET-1 expression.

  17. Improvement of plasma endothelin-1 and nitric oxide in patients with systemic sclerosis by bosentan therapy.

    PubMed

    Kawashiri, Shin-ya; Ueki, Yukitaka; Terada, Kaoru; Yamasaki, Satoshi; Aoyagi, Kiyoshi; Kawakami, Atsushi

    2014-02-01

    The aim of this study was to evaluate the effects of bosentan on plasma endothelin-1 (ET-1) and nitric oxide (NO) as pulmonary hypertension (PH)-associated biochemical markers in patients with systemic sclerosis (SSc). Twenty-four SSc patients receiving bosentan for 24 weeks were registered in this prospective observational study. Ten patients were complicated with clinically suspected PH. Plasma levels of ET-1 and NO were assessed at baseline and after 24 weeks of treatment in SSc patients and in 15 healthy controls. Plasma levels of ET-1 and NO at baseline were significantly higher in SSc patients than in healthy controls (p < 0.000), and they were also significantly higher in SSc patients with PH than in those without PH (p < 0.01). Plasma ET-1 levels were significantly decreased after 24 weeks of bosentan therapy (p < 0.0001), and ET-1 levels of SSc patients with PH decreased to a level comparable to that in patients without PH. In the 10 SSc patients with PH, changes in plasma ET-1 levels during the 24 weeks of the study were significantly larger in the 5 patients whose functional class (FC) improved than in the 5 patients whose FC was unchanged (p < 0.05). Plasma NO levels were also slightly decreased in SSc patients after 24 weeks of bosentan therapy. Plasma ET-1 levels could reflect the presence and severity of PH in SSc patients. Additionally, changes in plasma ET-1 levels may indicate the response to bosentan therapy in SSc patients with PH.

  18. A Pathogenetic Role for Endothelin-1 in Peritoneal Dialysis-Associated Fibrosis

    PubMed Central

    Busnadiego, Oscar; Loureiro-Álvarez, Jesús; Sandoval, Pilar; Lagares, David; Dotor, Javier; Pérez-Lozano, María Luisa; López-Armada, María J.; Lamas, Santiago; López-Cabrera, Manuel

    2015-01-01

    In patients undergoing peritoneal dialysis (PD), chronic exposure to nonphysiologic PD fluids elicits low-grade peritoneal inflammation, leading to fibrosis and angiogenesis. Phenotype conversion of mesothelial cells into myofibroblasts, the so-called mesothelial-to-mesenchymal transition (MMT), significantly contributes to the peritoneal dysfunction related to PD. A number of factors have been described to induce MMT in vitro and in vivo, of which TGF-β1 is probably the most important. The vasoconstrictor peptide endothelin-1 (ET-1) is a transcriptional target of TGF-β1 and mediates excessive scarring and fibrosis in several tissues. This work studied the contribution of ET-1 to the development of peritoneal damage and failure in a mouse model of PD. ET-1 and its receptors were expressed in the peritoneal membrane and upregulated on PD fluid exposure. Administration of an ET receptor antagonist, either bosentan or macitentan, markedly attenuated PD-induced MMT, fibrosis, angiogenesis, and peritoneal functional decline. Adenovirus-mediated overexpression of ET-1 induced MMT in human mesothelial cells in vitro and promoted the early cellular events associated with peritoneal dysfunction in vivo. Notably, TGF-β1–blocking peptides prevented these actions of ET-1. Furthermore, a positive reciprocal relationship was observed between ET-1 expression and TGF-β1 expression in human mesothelial cells. These results strongly support a role for an ET-1/TGF-β1 axis as an inducer of MMT and subsequent peritoneal damage and fibrosis, and they highlight ET-1 as a potential therapeutic target in the treatment of PD-associated dysfunction. PMID:25012164

  19. Endothelin@25 - new agonists, antagonists, inhibitors and emerging research frontiers: IUPHAR Review 12.

    PubMed

    Maguire, J J; Davenport, A P

    2014-12-01

    Since the discovery of endothelin (ET)-1 in 1988, the main components of the signalling pathway have become established, comprising three structurally similar endogenous 21-amino acid peptides, ET-1, ET-2 and ET-3, that activate two GPCRs, ETA and ETB . Our aim in this review is to highlight the recent progress in ET research. The ET-like domain peptide, corresponding to prepro-ET-193-166 , has been proposed to be co-synthesized and released with ET-1, to modulate the actions of the peptide. ET-1 remains the most potent vasoconstrictor in the human cardiovascular system with a particularly long-lasting action. To date, the major therapeutic strategy to block the unwanted actions of ET in disease, principally in pulmonary arterial hypertension, has been to use antagonists that are selective for the ETA receptor (ambrisentan) or that block both receptor subtypes (bosentan). Macitentan represents the next generation of antagonists, being more potent than bosentan, with longer receptor occupancy and it is converted to an active metabolite; properties contributing to greater pharmacodynamic and pharmacokinetic efficacy. A second strategy is now being more widely tested in clinical trials and uses combined inhibitors of ET-converting enzyme and neutral endopeptidase such as SLV306 (daglutril). A third strategy based on activating the ETB receptor, has led to the renaissance of the modified peptide agonist IRL1620 as a clinical candidate in delivering anti-tumour drugs and as a pharmacological tool to investigate experimental pathophysiological conditions. Finally, we discuss biased signalling, epigenetic regulation and targeting with monoclonal antibodies as prospective new areas for ET research.

  20. Knockout of Endothelial Cell-Derived Endothelin-1 Attenuates Skin Fibrosis but Accelerates Cutaneous Wound Healing

    PubMed Central

    Makino, Katsunari; Jinnin, Masatoshi; Aoi, Jun; Kajihara, Ikko; Makino, Takamitsu; Fukushima, Satoshi; Sakai, Keisuke; Nakayama, Kazuhiko; Emoto, Noriaki; Yanagisawa, Masashi; Ihn, Hironobu

    2014-01-01

    Endothelin (ET)-1 is known for the most potent vasoconstrictive peptide that is released mainly from endothelial cells. Several studies have reported ET-1 signaling is involved in the process of wound healing or fibrosis as well as vasodilation. However, little is known about the role of ET-1 in these processes. To clarify its mechanism, we compared skin fibrogenesis and wound repair between vascular endothelial cell-specific ET-1 knockout mice and their wild-type littermates. Bleomycin-injected fibrotic skin of the knockout mice showed significantly decreased skin thickness and collagen content compared to that of wild-type mice, indicating that bleomycin-induced skin fibrosis is attenuated in the knockout mice. The mRNA levels of transforming growth factor (TGF)-β were decreased in the bleomycin-treated skin of ET-1 knockout mice. On the other hand, skin wound healing was accelerated in ET-1 knockout mice, which was indicated by earlier granulation tissue reduction and re-epithelialization in these mice. The mRNA levels of TGF-β, tumor necrosis factor (TNF)-α and connective tissue growth factor (CTGF) were reduced in the wound of ET-1 knockout mice. In endothelial ET-1 knockout mouse, the expression of TNF-α, CTGF and TGF-β was down-regulated. Bosentan, an antagonist of dual ET receptors, is known to attenuate skin fibrosis and accelerate wound healing in systemic sclerosis, and such contradictory effect may be mediated by above molecules. The endothelial cell-derived ET-1 is the potent therapeutic target in fibrosis or wound healing, and investigations of the overall regulatory mechanisms of these pathological conditions by ET-1 may lead to a new therapeutic approach. PMID:24853267

  1. Endothelin-1 in osteoarthritic chondrocytes triggers nitric oxide production and upregulates collagenase production

    PubMed Central

    Manacu, Christina Alexandra; Martel-Pelletier, Johanne; Roy-Beaudry, Marjolaine; Pelletier, Jean-Pierre; Fernandes, Julio C; Shipkolye, Fazool S; Mitrovic, Dragoslav R; Moldovan, Florina

    2005-01-01

    The mechanism of endothelin-1 (ET-1)-induced nitric oxide (NO) production, MMP-1 production and MMP-13 production was investigated in human osteoarthritis chondrocytes. The cells were isolated from human articular cartilage obtained at surgery and were cultured in the absence or presence of ET-1 with or without inhibitors of protein kinase or LY83583 (an inhibitor of soluble guanylate cyclase and of cGMP). MMP-1, MMP-13 and NO levels were then measured by ELISA and Griess reaction, respectively. Additionally, inducible nitric oxide synthase (iNOS) and phosphorylated forms of p38 mitogen-activated protein kinase, p44/42, stress-activated protein kinase/Jun-N-terminal kinase and serine-threonine Akt kinase were determined by western blot. Results show that ET-1 greatly increased MMP-1 and MMP-13 production, iNOS expression and NO release. LY83583 decreased the production of both metalloproteases below basal levels, whereas the inhibitor of p38 kinase, SB202190, suppressed ET-1-stimulated production only. Similarly, the ET-1-induced NO production was partially suppressed by the p38 kinase inhibitor and was completely suppressed by the protein kinase A kinase inhibitor KT5720 and by LY83583, suggesting the involvement of these enzymes in relevant ET-1 signalling pathways. In human osteoarthritis chondrocytes, ET-1 controls the production of MMP-1 and MMP-13. ET-1 also induces NO release via iNOS induction. ET-1 and NO should thus become important target molecules for future therapies aimed at stopping cartilage destruction. PMID:15743480

  2. Increased endothelin-1 vasoconstriction in mesenteric resistance arteries after superior mesenteric ischaemia-reperfusion

    PubMed Central

    Martínez-Revelles, S; Caracuel, L; Márquez-Martín, A; Dantas, AP; Oliver, E; D'Ocon, P; Vila, E

    2012-01-01

    BACKGROUND AND PURPOSE Endothelin-1 (ET-1) plays an important role in the maintenance of vascular tone. We aimed to evaluate the influence of superior mesenteric artery (SMA) ischaemia-reperfusion (I/R) on mesenteric resistance artery vasomotor function and the mechanism involved in the changes in vascular responses to ET-1. EXPERIMENTAL APPROACH SMA from male Sprague-Dawley rats was occluded (90 min) and following reperfusion (24 h), mesenteric resistance arteries were dissected. Vascular reactivity was studied using wire myography. Protein and mRNA expression, superoxide anion (O2•−) production and ET-1 plasma concentration were evaluated by immunofluorescence, real-time quantitative PCR, ethidium fluorescence and elisa, respectively. KEY RESULTS I/R increased ET-1 plasma concentration, ET-1-mediated vasoconstriction and ETB mRNA expression, and down-regulated ETA mRNA expression. Immunofluorescence confirmed mRNA results and revealed an increase in ETB receptors in the mesenteric resistance artery media layer after I/R. Therefore, the ETB receptor agonist sarafotoxin-6 induced a contraction that was inhibited by the ETB receptor antagonist BQ788 only in vessels, with and without endothelium, from I/R rats. Furthermore, BQ788 potentiated ET-1 vasoconstriction only in sham rats. Endothelium removal in rings from I/R rats unmasked the inhibition of ET-1 vasoconstriction by BQ788. Endothelium removal, Nω-nitro-L-arginine methyl ester and superoxide dismutase abolished the differences in ET-1 vasoconstriction between sham and I/R rats. We also found that I/R down-regulates endothelial NOS mRNA expression and concomitantly enhanced O2•− production by increasing NADPH oxidase 1 (NOX-1) and p47phox mRNA. CONCLUSIONS AND IMPLICATIONS Mesenteric I/R potentiated the ET-1-mediated vasoconstriction by a mechanism that involves up-regulation of muscular ETB receptors and decrease in NO bioavailability. PMID:21806604

  3. Intradermal endothelin-1 excites bombesin-responsive superficial dorsal horn neurons in the mouse

    PubMed Central

    Akiyama, T.; Nagamine, M.; Davoodi, A.; Iodi Carstens, M.; Cevikbas, F.; Steinhoff, M.

    2015-01-01

    Endothelin-1 (ET-1) has been implicated in nonhistaminergic itch. Here we used electrophysiological methods to investigate whether mouse superficial dorsal horn neurons respond to intradermal (id) injection of ET-1 and whether ET-1-sensitive neurons additionally respond to other pruritic and algesic stimuli or spinal superfusion of bombesin, a homolog of gastrin-releasing peptide (GRP) that excites spinal itch-signaling neurons. Single-unit recordings were made from lumbar dorsal horn neurons in pentobarbital-anesthetized C57BL/6 mice. We searched for units that exhibited elevated firing after id injection of ET-1 (1 μg/μl). Responsive units were further tested with mechanical stimuli, bombesin (spinal superfusion, 200 μg·ml−1·min−1), heating, cooling, and additional chemicals [histamine, chloroquine, allyl isothiocyanate (AITC), capsaicin]. Of 40 ET-1-responsive units, 48% responded to brush and pinch [wide dynamic range (WDR)] and 52% to pinch only [high threshold (HT)]. Ninety-three percent responded to noxious heat, 50% to cooling, and >70% to histamine, chloroquine, AITC, and capsaicin. Fifty-seven percent responded to bombesin, suggesting that they participate in spinal itch transmission. That most ET-1-sensitive spinal neurons also responded to pruritic and algesic stimuli is consistent with previous studies of pruritogen-responsive dorsal horn neurons. We previously hypothesized that pruritogen-sensitive neurons signal itch. The observation that ET-1 activates nociceptive neurons suggests that both itch and pain signals may be generated by ET-1 to result in simultaneous sensations of itch and pain, consistent with observations that ET-1 elicits both itch- and pain-related behaviors in animals and burning itch sensations in humans. PMID:26311187

  4. Role of endothelin-1 antagonist; bosentan, against cisplatin-induced nephrotoxicity in male and female rats

    PubMed Central

    Jokar, Zahra; Nematbakhsh, Mehdi; Moeini, Maryam; Talebi, Ardeshir

    2015-01-01

    Background: Cisplatin (CP) is a chemotherapy drug, with the major side effect of nephrotoxicity. The level of endothelin-1 (ET-1) increases during nephrotoxicity, which is accompanied with vasoconstrictive properties. Bosentan (BOS) is a nonselective ET-1 receptor antagonist, having vasodilatory and anti-hypertension effects. The purpose of this study was to investigate the renoprotective effect of BOS against CP-induced nephrotoxicity in male and female rats. Materials and Methods: Male and female rats were divided into six groups; groups 1–3 and 4–6 were male and female rats, respectively. Animals in groups 1 and 4 were considered as negative control and groups 2 and 5 considered as positive control groups received BOS (30 mg/kg/day) alone and CP (2.5 mg/kg/day) alone, respectively, for 1-week. The animals in groups 3 and 6 were treated with both CP and BOS. Finally, serum parameters were measured, and the kidney tissue was subjected to staining to evaluate tissue damage. Results: The serum levels of blood urea nitrogen and creatinine, kidney tissue damage score and kidney weight elevated, and body weight significantly decreased in both CP alone and in CP plus BOS-treated groups when compared with the control groups (P < 0.05), while BOS did not ameliorate these parameters neither in males nor in females. No significant differences were observed in serum levels of nitrite and malondialdehyde between the groups, but kidney tissue level of nitrite decreased significantly in CP alone and CP plus BOS-treated groups (P < 0.05). Conclusion: Renoprotective effect of BOS, as ET-1 blocker, was not observed against CP-induced nephrotoxicity neither in male nor in female rats. This is while BOS promoted the severity of injuries in females. PMID:26015909

  5. Effect of endothelin receptor antagonist bosentan on plasma leptin concentration in acute myocardial infarction in rats.

    PubMed

    Ostrowski, Robert P.; Januszewski, Sławomir; Kowalska, Zdzisława; Kapuściński, Andrzej

    2003-09-01

    The aim of the study was to evaluate the effect of endothelin receptor antagonism on plasma leptin level after myocardial infarction (MI). In Wistar rats under chloral hydrate anesthesia, MI was performed by ligation of the left coronary artery. The animals were divided into the following groups: control-sham (thoracotomy only), and two MI groups with or without bosentan treatment. Bosentan was given daily by gavage at the dose of 100 mg/kg. Treatment of animals started 2 days before MI and continued up to the fifth day. Concentration of leptin was measured by radioimmunoassay by means of 125I labeled antigen in the following time intervals: before MI or sham operation, 4, 24 and 48 h after surgery. Electrocardiogram (ECG), blood pressure, heart rate, arterial pO(2), pCO(2) and pH were periodically monitored. Two days after the MI animals were perfused retrograde into descending aorta with 2% triphenyltetrazolium chloride (TTC) and hearts were fixed by immersion in formalin for microscopic examination. Hearts were sectioned transaxially and size of MI was quantitated with morphometric methods. ECG, TTC staining and microscopic results confirmed development of MI. Morphometric methods did not show significant differences in infarct size between bosentan treated and untreated groups. Concentration of leptin in plasma in untreated group significantly increased already 4 h after MI. In bosentan treated animals this increase appeared only after 24 h. In animals treated with bosentan also a significant diminution of MI mortality was observed. Our results indicate that bosentan has an important effect on leptin concentration in ischemic cardiovascular pathology.

  6. Adrenomedullin in rat follicles and corpora lutea: expression, functions and interaction with endothelin-1

    PubMed Central

    2011-01-01

    Background Adrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries. The present study investigated the interaction of ADM and endothelin-1 (ET-1) in follicles and newly formed corpora lutea (CL) and the actions of ADM on progesterone production in CL during pregnancy. Methods The peptide and gene expression level of adrenomedullin in small antral follicles, large antral follicles and CL was studied by real-time RT-PCR and EIA. The effect of ADM treatment on oestradiol production in 5-day follicular culture and on progesterone production from CL of different pregnant stages was measured by EIA. The interaction of ADM and ET-1 in follicles and CL at their gene expression level was studied by real-time RT-PCR. Results In the rat ovary, the gene expression of Adm increased during development from small antral follicles to large antral follicles and CL. In vitro treatment of preantral follicular culture for 5 days with ADM increased oestradiol production but did not affect follicular growth or ovulation rate. The regulation of progesterone production by ADM in CL in culture was pregnancy-stage dependent, inhibitory at early and late pregnancy but stimulatory at mid-pregnancy, which might contribute to the high progesterone production rate of the CL at mid-pregnancy. Moreover, the interaction between ADM and ET-1 at both the production and functional levels indicates that these two vasoactive peptides may form an important local, fine-tuning regulatory system together with LH and prolactin for progesterone production in rat CL. Conclusions As the CL is the major source of progesterone production even after the formation of placenta in rats, ADM may be an important regulator in progesterone production to meet the requirement of pregnancy. PMID:21824440

  7. A pathogenetic role for endothelin-1 in peritoneal dialysis-associated fibrosis.

    PubMed

    Busnadiego, Oscar; Loureiro-Álvarez, Jesús; Sandoval, Pilar; Lagares, David; Dotor, Javier; Pérez-Lozano, María Luisa; López-Armada, María J; Lamas, Santiago; López-Cabrera, Manuel; Rodríguez-Pascual, Fernando

    2015-01-01

    In patients undergoing peritoneal dialysis (PD), chronic exposure to nonphysiologic PD fluids elicits low-grade peritoneal inflammation, leading to fibrosis and angiogenesis. Phenotype conversion of mesothelial cells into myofibroblasts, the so-called mesothelial-to-mesenchymal transition (MMT), significantly contributes to the peritoneal dysfunction related to PD. A number of factors have been described to induce MMT in vitro and in vivo, of which TGF-β1 is probably the most important. The vasoconstrictor peptide endothelin-1 (ET-1) is a transcriptional target of TGF-β1 and mediates excessive scarring and fibrosis in several tissues. This work studied the contribution of ET-1 to the development of peritoneal damage and failure in a mouse model of PD. ET-1 and its receptors were expressed in the peritoneal membrane and upregulated on PD fluid exposure. Administration of an ET receptor antagonist, either bosentan or macitentan, markedly attenuated PD-induced MMT, fibrosis, angiogenesis, and peritoneal functional decline. Adenovirus-mediated overexpression of ET-1 induced MMT in human mesothelial cells in vitro and promoted the early cellular events associated with peritoneal dysfunction in vivo. Notably, TGF-β1-blocking peptides prevented these actions of ET-1. Furthermore, a positive reciprocal relationship was observed between ET-1 expression and TGF-β1 expression in human mesothelial cells. These results strongly support a role for an ET-1/TGF-β1 axis as an inducer of MMT and subsequent peritoneal damage and fibrosis, and they highlight ET-1 as a potential therapeutic target in the treatment of PD-associated dysfunction.

  8. Intradermal endothelin-1 excites bombesin-responsive superficial dorsal horn neurons in the mouse.

    PubMed

    Akiyama, T; Nagamine, M; Davoodi, A; Iodi Carstens, M; Cevikbas, F; Steinhoff, M; Carstens, E

    2015-10-01

    Endothelin-1 (ET-1) has been implicated in nonhistaminergic itch. Here we used electrophysiological methods to investigate whether mouse superficial dorsal horn neurons respond to intradermal (id) injection of ET-1 and whether ET-1-sensitive neurons additionally respond to other pruritic and algesic stimuli or spinal superfusion of bombesin, a homolog of gastrin-releasing peptide (GRP) that excites spinal itch-signaling neurons. Single-unit recordings were made from lumbar dorsal horn neurons in pentobarbital-anesthetized C57BL/6 mice. We searched for units that exhibited elevated firing after id injection of ET-1 (1 μg/μl). Responsive units were further tested with mechanical stimuli, bombesin (spinal superfusion, 200 μg·ml(-1)·min(-1)), heating, cooling, and additional chemicals [histamine, chloroquine, allyl isothiocyanate (AITC), capsaicin]. Of 40 ET-1-responsive units, 48% responded to brush and pinch [wide dynamic range (WDR)] and 52% to pinch only [high threshold (HT)]. Ninety-three percent responded to noxious heat, 50% to cooling, and >70% to histamine, chloroquine, AITC, and capsaicin. Fifty-seven percent responded to bombesin, suggesting that they participate in spinal itch transmission. That most ET-1-sensitive spinal neurons also responded to pruritic and algesic stimuli is consistent with previous studies of pruritogen-responsive dorsal horn neurons. We previously hypothesized that pruritogen-sensitive neurons signal itch. The observation that ET-1 activates nociceptive neurons suggests that both itch and pain signals may be generated by ET-1 to result in simultaneous sensations of itch and pain, consistent with observations that ET-1 elicits both itch- and pain-related behaviors in animals and burning itch sensations in humans.

  9. The effects of endothelin-1 on satellite glial cells in peripheral ganglia.

    PubMed

    Feldman-Goriachnik, Rachel; Hanani, Menachem

    2017-03-18

    Endothelins (ET) are a family of highly active neuropeptides with manifold influences via ET receptors (ETR) in both the peripheral and central nervous systems. We have shown previously that satellite glial cells (SGCs) in mouse trigeminal ganglia (TG) are extremely sensitive to ET-1 in evoking [Ca(2+)]in increase, apparently via ETBR activation, but there is no functional information on ETR in SGCs of other peripheral ganglia. Here we tested the effects of ET-1 on SGCs in nodose ganglia (NG), which is sensory, and superior cervical ganglia (Sup-CG), which is part of the sympathetic nervous system, and further investigated the influence of ET-1 on SGCs in TG. Using calcium imaging we found that SGCs in intact, freshly isolated NG and Sup-CG are highly sensitive to ET-1, with threshold concentration at 0.1nM. Our results showed that [Ca(2+)]in elevation in response to ET-1 was partially due to Ca(2+) influx from the extracellular space and partially to Ca(2+) release from intracellular stores. Using receptor selective ETR agonists and antagonists, we found that the responses were mediated by mixed ETAR/ETBR in SGCs of NG and predominantly by ETBR in SGCs of Sup-CG. By employing intracellular dye injection we examined coupling among SGCs around different neurons in the presence of 5nM ET-1 and observed coupling inhibition in all the three ganglion types. In summary, our work showed that SGCs in mouse sensory and sympathetic ganglia are highly sensitive to ET-1 and that this peptide markedly reduces SGCs coupling. We conclude that ET-1, which may participate in neuron-glia communications, has similar functions in wide range of peripheral ganglia.

  10. Attenuation of endothelin-1-induced calcium response by tyrosine kinase inhibitors in vascular smooth muscle cells.

    PubMed

    Liu, C Y; Sturek, M

    1996-06-01

    Although tyrosine kinases play an important role in cell growth and have been implicated in regulation of smooth muscle contraction, their role in agonist-induced myoplasmic Ca2+ responses is unclear. We examined effects of the tyrosine kinase inhibitors genistein and methyl 2,5-dihydroxycinnamate (MDHC) on the endothelin-1 (ET-1)-induced Ca2+ response and determined underlying mechanisms for the effects. Freshly isolated smooth muscle cells from porcine coronary arteries were loaded with fura 2 ester, and myoplasmic free Ca2+ (Ca2+ (m)) concentration was estimated with fura 2 microfluorometry. Both genistein and MDHC inhibited the initial transient Cam2+ response to ET by 54 and 81%, respectively (P < 0.05), in the presence of extracellular Ca2+. Genistein also significantly delayed the Cam2+ response, with the latent period from ET-1 application to the beginning of the Cam2+ response being increased from 1.08 +/- 0.17 to 2.65 +/- 0.52 min (P < 0.05). In the absence of extracellular Ca2+, genistein inhibited the ET-1-induced Cam2+ response by 93% (P < 0.05). The Cam2+ responses to caffeine (5 mM) or inositol trisphosphate (IP3) applied intracellularly via a patch-clamp pipette were not affected by genistein. Both genistein and MDHC also abolished the sustained Cam2+ response to ET-1. However, the Cam2+ response to depolarization by 80 mM K+ was not inhibited by MDHC and only inhibited 22% by genistein (P < 0.05). These results indicate that 1) activation of tyrosine kinases is an important regulatory mechanism for the ET-1-induced Cam2+ response in vascular smooth muscle and 2) tyrosine kinases mediate ET-1-induced Ca2+ release with no direct effect on IP3-mediated Ca2+ release. Thus ET-1-mediated signaling upstream of IP3 interaction with the Ca2+ stores is regulated by tyrosine kinases.

  11. Endothelin-1 decreases endothelial PPARγ signaling and impairs angiogenesis after chronic intrauterine pulmonary hypertension

    PubMed Central

    Wolf, David; Tseng, Nancy; Seedorf, Gregory; Roe, Gates; Abman, Steven H.

    2013-01-01

    Increased endothelin-1 (ET-1) disrupts angiogenesis in persistent pulmonary hypertension of the newborn (PPHN), but pathogenic mechanisms are unclear. Peroxisome proliferator activated receptor γ (PPARγ) is decreased in adult pulmonary hypertension, but whether ET-1-PPARγ interactions impair endothelial cell function and angiogenesis in PPHN remains unknown. We hypothesized that increased PPHN pulmonary artery endothelial cell (PAEC) ET-1 production decreases PPARγ signaling and impairs tube formation in vitro. Proximal PAECs were harvested from fetal sheep after partial ligation of the ductus arteriosus in utero (PPHN) and controls. PPARγ and phospho-PPARγ protein were compared between normal and PPHN PAECs ± ET-1 and bosentan (ETA/ETB receptor blocker). Tube formation was assessed in response to PPARγ agonists ± ET-1, N-nitro-l-arginine (LNA) (NOS inhibitor), and PPARγ siRNA. Endothelial NO synthase (eNOS), phospho-eNOS, and NO production were measured after exposure to PPARγ agonists and PPARγ siRNA. At baseline, PPHN PAECs demonstrate decreased tube formation and PPARγ protein expression and activity. PPARγ agonists restored PPHN tube formation to normal. ET-1 decreased normal and PPHN PAEC tube formation, which was rescued by PPARγ agonists. ET-1 decreased PPARγ protein and activity, which was prevented by bosentan. PPARγ agonists increased eNOS protein and activity and NO production in normal and PPHN PAECs. LNA inhibited the effect of PPARγ agonists on tube formation. PPARγ siRNA decreased eNOS protein and tube formation in normal PAECs. We conclude that ET-1 decreases PPARγ signaling and contributes to PAEC dysfunction and impaired angiogenesis in PPHN. We speculate that therapies aimed at decreasing ET-1 production will restore PPARγ signaling, preserve endothelial function, and improve angiogenesis in PPHN. PMID:24337925

  12. Novel Vasoregulatory Aspects of Hereditary Angioedema: the Role of Arginine Vasopressin, Adrenomedullin and Endothelin-1.

    PubMed

    Kajdácsi, Erika; Jani, Péter K; Csuka, Dorottya; Varga, Lilian; Prohászka, Zoltán; Farkas, Henriette; Cervenak, László

    2016-02-01

    The elevation of bradykinin (BK) level during attacks of hereditary angioedema due to C1-Inhibitor deficiency (C1-INH-HAE) is well known. We previously demonstrated that endothelin-1 (ET-1) level also increases during C1-INH-HAE attacks. Although BK and ET-1 are both potent vasoactive peptides, the vasoregulatory aspect of the pathomechanism of C1-INH-HAE has not yet been investigated. Hence we studied the levels of vasoactive peptides in controls and in C1-INH-HAE patients, as well as evaluated their changes during C1-INH-HAE attacks. The levels of arginine vasopressin (AVP), adrenomedullin (ADM) and ET-1 were measured in the plasma of 100 C1-INH-HAE patients in inter-attack periods and of 111 control subjects, using BRAHMS Kryptor technologies. In 18 of the 100 C1-INH-HAE patients, the levels of vasoactive peptides were compared in blood samples obtained during attacks, or in inter-attack periods. AVP, ADM and ET-1 levels were similar in inter-attack samples from C1-INH-HAE patients and in the samples of controls, although cardiovascular risk has an effect on the levels of vasoactive peptides in both groups. The levels of all three vasoactive peptides increased during C1-INH-HAE attacks. Moreover, the levels of ET-1 and ADM as well as their changes during attacks were significantly correlated. This study demonstrated that vascular regulation by vasoactive peptides is affected during C1-INH-HAE attacks. Our results suggest that the cooperation of several vasoactive peptides may be necessary to counterbalance the actions of excess BK, and to terminate the attacks. This may reveal a novel pathophysiological aspect of C1-INH-HAE.

  13. Endothelin@25 – new agonists, antagonists, inhibitors and emerging research frontiers: IUPHAR Review 12

    PubMed Central

    Maguire, J J; Davenport, A P

    2014-01-01

    Since the discovery of endothelin (ET)-1 in 1988, the main components of the signalling pathway have become established, comprising three structurally similar endogenous 21-amino acid peptides, ET-1, ET-2 and ET-3, that activate two GPCRs, ETA and ETB. Our aim in this review is to highlight the recent progress in ET research. The ET-like domain peptide, corresponding to prepro-ET-193–166, has been proposed to be co-synthesized and released with ET-1, to modulate the actions of the peptide. ET-1 remains the most potent vasoconstrictor in the human cardiovascular system with a particularly long-lasting action. To date, the major therapeutic strategy to block the unwanted actions of ET in disease, principally in pulmonary arterial hypertension, has been to use antagonists that are selective for the ETA receptor (ambrisentan) or that block both receptor subtypes (bosentan). Macitentan represents the next generation of antagonists, being more potent than bosentan, with longer receptor occupancy and it is converted to an active metabolite; properties contributing to greater pharmacodynamic and pharmacokinetic efficacy. A second strategy is now being more widely tested in clinical trials and uses combined inhibitors of ET-converting enzyme and neutral endopeptidase such as SLV306 (daglutril). A third strategy based on activating the ETB receptor, has led to the renaissance of the modified peptide agonist IRL1620 as a clinical candidate in delivering anti-tumour drugs and as a pharmacological tool to investigate experimental pathophysiological conditions. Finally, we discuss biased signalling, epigenetic regulation and targeting with monoclonal antibodies as prospective new areas for ET research. PMID:25131455

  14. β-arrestin1 at the cross-road of endothelin-1 signaling in cancer.

    PubMed

    Rosanò, Laura; Bagnato, Anna

    2016-07-29

    The advent of targeted therapeutics in human cancer has begun to find novel druggable targets and, in this context, the endothelin-1 receptor (ET-1R), namely ETA receptor (ETAR) and ETB receptor, among the GPCR family represents a class of highly druggable molecules in cancer. ET-1R are aberrantly expressed in human malignancies, potentially representing prognostic factors. Their activation by ligand stimulation initiate signaling cascades activating different downstream effectors, allowing precise control over multiple signaling pathways. ET-1R regulates cell proliferation, survival, motility, cytoskeletal changes, angiogenesis, metastasis as well as drug resistance. The molecular events underlying these responses are the activation of transcriptional factors and coactivators, and downstream genes, acting as key players in tumor growth and progression. ET-1R represent crucial cancer targets that have been exploited for ET-1R therapeutics. Importantly, efforts to explore new information of ETAR in cancer have uncovered that their functions are crucially regulated by multifunctional scaffold protein β-arrestins (β-arrs) which orchestrate the multidimensionality of ETAR signaling into highly regulated and distinct signaling complexes, a property that is highly advantageous for tumor signaling. Moreover, the role of β-arr1 in ET-1 signaling in cancer highlights why the pleiotropic effects of ET-1 and its dynamic signaling are more complex than previously recognized. In order to improve therapeutic strategies that interfere with the widespread effects of ET-1R, it is important to consider antagonists able to turn the receptors "off" selectively controlling β-arr1-dependent signaling, highlighting the possibility that targeting ETAR/β-arr1 may display a large therapeutic window in cancer.

  15. Endothelin-1 stimulates catalase activity through the PKCδ-mediated phosphorylation of serine 167.

    PubMed

    Rafikov, Ruslan; Kumar, Sanjiv; Aggarwal, Saurabh; Hou, Yali; Kangath, Archana; Pardo, Daniel; Fineman, Jeffrey R; Black, Stephen M

    2014-02-01

    Our previous studies have shown that endothelin-1 (ET-1) stimulates catalase activity in endothelial cells and in lambs with acute increases in pulmonary blood flow (PBF), without altering gene expression. The purpose of this study was to investigate the molecular mechanism by which this occurs. Exposing pulmonary arterial endothelial cells to ET-1 increased catalase activity and decreased cellular hydrogen peroxide (H2O2) levels. These changes correlated with an increase in serine-phosphorylated catalase. Using the inhibitory peptide δV1.1, this phosphorylation was shown to be protein kinase Cδ (PKCδ) dependent. Mass spectrometry identified serine 167 as the phosphorylation site. Site-directed mutagenesis was used to generate a phospho-mimic (S167D) catalase. Activity assays using recombinant protein purified from Escherichia coli or transiently transfected COS-7 cells demonstrated that S167D catalase had an increased ability to degrade H2O2 compared to the wild-type enzyme. Using a phospho-specific antibody, we were able to verify that pS167 catalase levels are modulated in lambs with acute increases in PBF in the presence and absence of the ET receptor antagonist tezosentan. S167 is located on the dimeric interface, suggesting it could be involved in regulating the formation of catalase tetramers. To evaluate this possibility we utilized analytical gel filtration to examine the multimeric structure of recombinant wild-type and S167D catalase. We found that recombinant wild-type catalase was present as a mixture of monomers and dimers, whereas S167D catalase was primarily tetrameric. Further, the incubation of wild-type catalase with PKCδ was sufficient to convert wild-type catalase into a tetrameric structure. In conclusion, this is the first report indicating that the phosphorylation of catalase regulates its multimeric structure and activity.

  16. Endothelin-1 downregulates sperm phagocytosis by neutrophils in vitro: A physiological implication in bovine oviduct immunity

    PubMed Central

    MAREY, Mohamed Ali; YOUSEF, Mohamed Samy; LIU, Jinghui; MORITA, Kazuhiro; SASAKI, Motoki; HAYAKAWA, Hiroyuki; SHIMIZU, Takashi; ELSHAHAWY, Ibrahim I.; MIYAMOTO, Akio

    2016-01-01

    The oviduct is an active contractile tube that provides the proper environment for sperm transport, capacitation and survival. Oviductal contractions are regulated by autocrine/paracrine secretion of several factors, such as prostaglandins (PGs) and endothelin-1 (EDN-1). We have previously shown that during the preovulatory stage, sperm are exposed to polymorphonuclear neutrophils (PMNs) in the bovine oviduct, and the bovine oviduct epithelial cells (BOECs) secrete molecules including PGE2 that suppress sperm phagocytosis by PMNs in vitro. In this study, we investigated the possible effects of EDN-1 on the phagocytic activity of PMNs toward sperm. The local concentrations of EDN-1 in oviduct fluid and BOEC culture medium ranged from 10–10 to 10–11 M as determined by EIA. Phagocytosis and superoxide production were assayed by co-incubation of sperm pretreated to induce capacitation with PMNs exposed to EDN-1 (0, 10–11, 10–10, 10–9, and 10–8 M) for 2 h. EDN-1 suppressed dose dependently (10–11 to 10–8 M) the phagocytic activity for sperm and superoxide production of PMNs in response to capacitated sperm. Moreover, this suppression was eliminated by an ETB receptor antagonist (BQ-788). EDN-1 suppressed mRNA expression of EDN-1 and ETB but not ETA receptors in PMNs, suggesting the ETB receptor-mediated pathway. Scanning electron microscopic observation revealed that incubation of PMNs with EDN-1 (10–9 M) completely suppressed the formation of DNA-based neutrophil extracellular traps for sperm entanglement. The results provide evidence indicating that EDN-1 may be involved in the protection of sperm from phagocytosis by PMNs in the bovine oviduct, supporting sperm survival until fertilization. PMID:26781611

  17. Characterization of flow-regulated cortical collecting duct endothelin-1 production.

    PubMed

    Ramkumar, Nirupama; Gao, Yang; Kohan, Donald E

    2017-02-01

    Collecting duct (CD) endothelin-1 (ET-1) is an autocrine inhibitor of Na(+) and water reabsorption. Salt or water loading increases CD ET-1 production; this is likely due, at least in part, to increased tubule fluid flow. The mechanisms by which flow stimulates CD ET-1 production are incompletely understood. In particular, flow induction of cortical CD (CCD) and inner medullary CD (IMCD) ET-1 synthesis may occur via different mechanisms. Since flow-mediated ET-1 production in IMCD has been more extensively characterized than in the CCD, this study was undertaken to further examine putative signaling pathways involved in flow-stimulated CCD ET-1 production. The CD cell line, mpkCCDcl4, was exposed to static or flow (2 dyne/cm(2) for 2 h) conditions and ET-1/GAPDH mRNA levels were assessed. Intracellular Ca(2+), Ca(2+)-stimulated Ca(2+) release, calcineurin, and protein kinase c α/β isoforms were all involved in the ET-1 flow response. TRPC6, but not other CD-expressed TRP channels (TRPC3, 4, and 5, or TRPV4) played a role in the ET-1 flow response. Purinergic signaling pathways and cilia were not involved in the ET-1 flow response. Based on these and previously published findings, we present a comparison of flow-stimulated CD ET-1 production between CCD and IMCD We suggest that flow-stimulated CCD ET-1 production may be more involved in responding to Na(+) delivery, while IMCD ET-1 production may be more responsive to water and solute delivery; the responsible pathways for mediating these effects in the two regions of the CD appear to be substantially distinct from one another.

  18. Applying cardiothermography and electrophysiology to differentiate between the ischemic and arrhythmogenic actions of endothelin-1

    NASA Astrophysics Data System (ADS)

    Geller, Laslu; Szabo, Tamas; Selmeci, Laszlo; Merkely, Bela; Juhasz-Nagy, Alexander; Solti, Francis

    1999-07-01

    Endothelin-1 (ET-1) is the strongest vasoconstrictor peptide isolated so far, which has a known arrhythmogenic property, as well. Intracoronary ET-1 infusion may cause ventricular premature beats (VES), ventricular tachycardia (VT) and ventricular fibrillation (VF). The aim of our study was to compare the thermographic and electrophysiologic changes during left anterior describing coronary artery (LAD) occlusion and ic. ET-1 administration. The measurements were performed on 16 sodium-pentobarbital anesthetized, open- chest dogs. The dogs were divided into 2 groups. In group A LAD occlusion was carried out for 30 minutes, followed by a 60 min reperfusion period. In group B ET-1 was administered into LAD at 60 pmol/min dose. Arterial blood pressure, coronary blood flow (CBF), heart rate (HR) and standard ECG were monitored. IR thermography was applied to follow epimyocardial heat emission changes. To determine the electrophysiological changes an endocardial monophasic action potential (MAP) electrode was inserted into the right ventricle and an MAP electrode was placed onto the left ventricle and an MAP electrode was placed onto the left ventricular epicardium. In group A CBF returned to baseline 20 minutes after releasing the occlusion. Ic. ET-1 infusion significantly reduced CBF in group B. Epimyocardial temperature decreased in both groups. In group A ventricular extrasystoles were noticed. In group B ventricular techycardias occurred with satisfactory CBF in 4 cases. In 5 dogs VF was observed. MAP duration 90 (MAPD90) decreased significantly in group A whereas significant increase was observed in group B. The left ventricular epicardial upstroke velocities correlated excellently with the epimyocardial temperature changes. Our result suggests that the decrease of epimyocardial heat emission and upstroke velocity correlates well in both groups, indicating ischemia, whereas the lack of the other ischemic MAP signs and the change of MAPD90 in the opposite direction

  19. Prenatal Oxycodone Exposure Alters CNS Endothelin Receptor Expression in Neonatal Rats.

    PubMed

    Devarapalli, M; Leonard, M; Briyal, S; Stefanov, G; Puppala, B L; Schweig, L; Gulati, A

    2016-05-01

    Prenatal opioid exposure such as oxycodone is linked to significant adverse effects on the developing brain. Endothelin (ET) and its receptors are involved in normal development of the central nervous system. Opioid tolerance and withdrawal are mediated through ET receptors. It is possible that adverse effect of oxycodone on the developing brain is mediated through ET receptors. We evaluated brain ETA and ETB receptor expression during postnatal development in rats with prenatal oxycodone exposure. Timed pregnant Sprague-Dawley rats received either oxycodone or placebo throughout gestation. After birth, male rat pups were sacrificed on postnatal day (PND) 1, 7, 14 or 28. Brain ETA and ETB receptor expression was determined by Western blot analysis. Oxycodone pups compared to placebo demonstrated congenital malformations of the face, mouth, and vertebrae at the time of birth [4/69 (5.7%) vs. 0/60 (0%); respectively] and intrauterine growth retardation [10/69 (15%) vs. 2/60 (3.3%); respectively]. On PND 28, oxycodone pups compared to placebo had lower body and kidney weight. ETA receptor expression in the oxycodone group was significantly higher compared to placebo on PND 1 (p=0.035), but was similar on PND 7, 14, or 28. ETB receptor expression decreased in oxycodone compared to placebo on PND 1 and 7 (p=0.001); and increased on PND 28 (p=0.002), but was similar on PND 14. Oxycodone-exposed rat pups had lower birth weight and postnatal weight gain and greater congenital malformations. ETB receptor expression is altered in the brain of oxycodone-treated rat pups indicating a possible delay in CNS development.

  20. Endothelin: Visualization of mRNAs by in situ hybridization provides evidence for local action

    SciTech Connect

    MacCumber, M.W.; Ross, C.A.; Glaser, B.M.; Snyder, S.H. )

    1989-09-01

    Endothelin (ET) is a recently identified vasoactive peptide with three isoforms for which three genes have been cloned. The cellular sites of synthesis of this peptide have not yet been identified in vivo. Using Northern blot analysis, we have detected two forms of ET mRNA in rat tissues: a 3.7-kilobase form in the kidney, eye, and brain, a 2.5-kilobase form in the intestine, and both forms in the lung. We have localized these forms of ET mRNA in several rat tissues using in situ hybridization. In the 19-day rat fetus, ET mRNA is highest in the lung, intestine, and meninges. At high resolution, ET mRNA is localized in the lung to respiratory epithelial cells of bronchioles and apparently in blood vessels. In adult tissues, ET mRNA is present throughout the lung, in the renal medulla vasa recta, and in the iris of the eye. ET mRNA is synthesized in close proximity to ET binding sites in many organs (e.g., lung, kidney, intestine, and eye), suggesting a local action of this peptide. However, in other areas (e.g., heart and renal cortex), ET binding sites are present in the absence of ET mRNA, suggesting an action of ET from the bloodstream or from neurons. Northern blot analysis of ET mRNA in microvascular endothelial cells in culture indicates that ET is synthesized in small blood vessels and regulated similarly to its regulation in large vessels. Our results provide evidence that ET, like other regulatory peptides, may serve in several tissues as a neuromodulator or local hormone.

  1. Peripheral venous congestion causes time- and dose-dependent release of endothelin-1 in humans.

    PubMed

    Lin, Jeffrey; Chudasama, Neelesh; Hayashi, Yacki; Hawk, Christopher; Ramnauth, Sahadeo D; Wong, Ka Yuk; Harxhi, Ante; Onat, Duygu; Wakabayashi, Michiyori; Uriel, Nir; Jorde, Ulrich P; LeJemtel, Thierry H; Sabbah, Hani N; Demmer, Ryan T; Colombo, Paolo C

    2017-03-01

    Endothelin-1 (ET-1) is a pivotal mediator of vasoconstriction and inflammation in congestive states such as heart failure (HF) and chronic kidney disease (CKD). Whether peripheral venous congestion (VC) increases plasma ET-1 at pressures commonly seen in HF and CKD patients is unknown. We seek to characterize whether peripheral VC promotes time- and dose-dependent increases in plasma ET-1 and whether these changes are sustained after decongestion. We used a randomized, cross-over design in 20 healthy subjects (age 30 ± 7 years). To experimentally model VC, venous pressure was increased to either 15 or 30 mmHg (randomized at first visit) above baseline by inflating a cuff around the subject's dominant arm; the nondominant arm served as a noncongested control. We measured plasma ET-1 at baseline, after 20, 60 and 120 min of VC, and finally at 180 min (60 min after cuff release and decongestion). Plasma ET-1 progressively and significantly increased over 120 min in the congested arm relative to the control arm and to baseline values. This effect was dose-dependent: ET-1 increased by 45% and 100% at VC doses of 15 and 30 mmHg, respectively (P < 0.05), and declined after 60 min of decongestion though remaining significantly elevated compared to baseline. In summary, peripheral VC causes time- and dose-dependent increases in plasma ET-1. Of note, the lower dose of 15 mmHg (more clinically relevant to HF and CKD patients) was sufficient to raise ET-1. These findings support the potentially contributory, not merely consequential, role of VC in the pathophysiology of HF and CKD.

  2. Regorafenib Induces Rapid and Reversible Changes in Plasma Nitric Oxide and Endothelin-1

    PubMed Central

    Humphreys, Benjamin D.

    2012-01-01

    Background Hypertension is a toxicity of antiangiogenic therapies and a possible biomarker that identifies patients with superior cancer outcomes. Understanding its mechanism will aid in treatment and could lead to the development of other biomarkers for predicting toxicity and anticancer efficacy. Recent evidence implicates nitric oxide (NO) suppression and endothelin-1 (ET-1) stimulation as potential mechanisms leading to antiangiogenic therapy-induced hypertension. The aim of this study was to evaluate the effects of regorafenib, a novel broad-spectrum kinase inhibitor with activity against multiple targets, including vascular endothelial growth factor receptor 2 inhibition, on NO and ET-1 levels. Methods Regorafenib was administered to 32 subjects with gastrointestinal stromal tumor on a 3-week-on, 1-week-off basis. Plasma levels of NO and ET-1 were measured at baseline, 2, 4, and 6 weeks of therapy. Data analysis was by Wilcoxon rank-sum and paired t-tests. Results Twenty subjects (63%) developed regorafenib-induced hypertension. Two weeks after starting regorafenib therapy, plasma ET-1 levels increased (25% increase, P < 0.05) and NO was suppressed (20% decrease, P < 0.05). These normalized after 1-week washout but ET-1 rose again by 30% (P < 0.05) and NO fell by 50% (P < 0.05) after restarting regorafenib. Conclusions These findings indicate that regorafenib induces a coordinated and reversible suppression of NO and stimulation of ET-1. Whether NO and ET-1 might predict therapeutic efficacy in these patients requires further study. American Journal of Hypertension, advance online publication 12 July 2012. doi:10.1038/ajh.2012.97 PMID:22785409

  3. Potentiation by endothelin-1 of 5-hydroxytryptamine-induced contraction in coronary artery of the pig.

    PubMed Central

    Nakayama, K.; Ishigai, Y.; Uchida, H.; Tanaka, Y.

    1991-01-01

    1. In order to elucidate the physiological and potential pathological roles of endothelin-1 (ET-1) in coronary artery contraction and relaxation, we undertook the present study to examine the action of ET-1 itself, and the combined effects of ET-1 with vasoconstrictor agonists such as acetylcholine (ACh), histamine, and 5-hydroxytryptamine (5-HT), all of which have been implicated in the genesis of coronary spasm. 2. Isometric tension and cytosolic Ca2+ concentration ([Ca2+]i) in a ring segment of porcine coronary artery loaded with fura-2 were measured simultaneously. 3. ET-1 contracted the artery in a concentration-dependent manner; and nisoldipine, a Ca2+ channel blocking drug of the 1,4-dihydropyridine type, antagonized the ET-1 action non-competitively. A radio-receptor binding assay also indicated the mutually exclusive binding of ET-1 and (+)-[3H]-PN200-110, a Ca2+ channel ligand, to the membrane fraction of porcine coronary artery. 4. ET-1 (10-100 pM) increased tension and [Ca2+]i in a parallel manner, while at higher concentrations (1-10 nM) it produced further contraction with a small increase in [Ca2+]i. 5. ET-1 (30-100 pM) selectively potentiated the 5-HT-induced contraction 1.5 to 2 times over the control without causing a significant increase in [Ca2+]i, which seems to be qualitatively similar to a tumour promoting phorbol ester, 12-deoxyphorbol 13-isobutylate (DPB). Bay K 8644 (10 nM), on the other hand, potentiated the contraction in response to practically all agonists used and affected a concomitant increase in [Ca2+]i.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1810605

  4. FOXO1 Mediates the Autocrine Effect of Endothelin-1 on Endothelial Cell Survival

    PubMed Central

    Cifarelli, Vincenza; Lee, Sojin; Kim, Dae Hyun; Zhang, Ting; Kamagate, Adama; Slusher, Sandra; Bertera, Suzanne; Luppi, Patrizia; Trucco, Massimo

    2012-01-01

    Chronic hyperglycemia exerts a deleterious effect on endothelium, contributing to endothelial dysfunction and microvascular complications in poorly controlled diabetes. To understand the underlying mechanism, we studied the effect of endothelin-1 (ET-1) on endothelial production of Forkhead box O1 (FOXO1), a forkhead transcription factor that plays an important role in cell survival. ET-1 is a 21-amino acid peptide that is secreted primarily from endothelium. Using adenovirus-mediated gene transfer approach, we delivered FOXO1 cDNA into cultured human aorta endothelial cells. FOXO1 was shown to stimulate B cell leukemia/lymphoma 2-associated death promoter (BAD) production and promote cellular apoptosis. This effect was counteracted by ET-1. In response to ET-1, FOXO1 was phosphorylated and translocated from the nucleus to cytoplasm, resulting in inhibition of BAD production and mitigation of FOXO1-mediated apoptosis. Hyperglycemia stimulated FOXO1 O-glycosylation and promoted its nuclear localization in human aorta endothelial cells. This effect accounted for unbridled FOXO1 activity in the nucleus, contributing to augmented BAD production and endothelial apoptosis under hyperglycemic conditions. FOXO1 expression became deregulated in the aorta of both streptozotocin-induced diabetic mice and diabetic db/db mice. This hyperglycemia-elicited FOXO1 deregulation and its ensuing effect on endothelial cell survival was corrected by ET-1. Likewise, FoxO1 deregulation in the aorta of diabetic mice was reversible after the reduction of hyperglycemia by insulin therapy. These data reveal a mechanism by which FOXO1 mediated the autocrine effect of ET-1 on endothelial cell survival. FOXO1 deregulation, resulting from an impaired ability of ET-1 to control FOXO1 activity in endothelium, may contribute to hyperglycemia-induced endothelial lesion in diabetes. PMID:22570335

  5. Transforming growth factor-beta receptor requirements for the induction of the endothelin-1 gene.

    PubMed

    Castañares, Cristina; Redondo-Horcajo, Mariano; Magan-Marchal, Noemi; Lamas, Santiago; Rodriguez-Pascual, Fernando

    2006-06-01

    Expression of the endothelin (ET)-1 gene is subject to complex regulation by numerous factors, among which the cytokine transforming growth factor-beta (TGF-beta) is one of the most important. TGF-beta action is based on the activation of the Smad signaling pathway. Smad proteins activate transcription of the gene by cooperation with activator protein-1 (AP-1) at specific sites on the ET-1 promoter. Smad signaling pathway is initiated by binding of the cytokine to a heteromeric complex of type I and type II receptors. Signal is then propagated to the nucleus by specific members of the Smad family. Most cell types contain a type I receptor known as ALK5. However, endothelial cells are unique because they coexpress an additional type I receptor named ALK1. These forms do not constitute redundant receptors with the same function, but they actually activate different Smad-mediated expression programs that lead to specific endothelial phenotypes. TGF-beta/ALK5/Smad3 pathway is associated to a mature endothelium because it leads to inhibition of cell migration/proliferation. Conversely, TGF-beta/ALK1/Smad5 activates both processes and is more related to the angiogenic state. We have analyzed the TGF-beta receptor subtype requirements for the activation of the ET-1 gene. For that purpose, we have overexpressed type I receptor and Smad isoforms in endothelial cells and analyzed the effect on ET-1 expression. Our experiments indicate that TGF-beta induces ET-1 expression preferentially through the activation of the ALK5/Smad3 pathway and, therefore, the expression of the vaso-constrictor may be associated to a quiescent and mature endothelial phenotype.

  6. EXTRINSIC COAGULATION BLOCKADE ATTENUATES LUNG INJURY AND PROINFLAMMATORY CYTOKINE RELEASE AFTER INTRATRACHEAL LIPOPOLYSACCHARIDE

    EPA Science Inventory

    Initiation of coagulation by tissue factor (TF) is a potentially powerful regulator of local inflammatory responses. We hypothesized that blockade of TF-factor VIIa (FVIIa) complex would decrease lung inflammation and proinflammatory cytokine release after tracheal instillation o...

  7. Fano effect dominance over Coulomb blockade in transport properties of parallel coupled quantum dot system

    NASA Astrophysics Data System (ADS)

    Brogi, Bharat Bhushan; Chand, Shyam; Ahluwalia, P. K.

    2015-06-01

    Theoretical study of the Coulomb blockade effect on transport properties (Transmission Probability and I-V characteristics) for varied configuration of coupled quantum dot system has been studied by using Non Equilibrium Green Function(NEGF) formalism and Equation of Motion(EOM) method in the presence of magnetic flux. The self consistent approach and intra-dot Coulomb interaction is being taken into account. As the key parameters of the coupled quantum dot system such as dot-lead coupling, inter-dot tunneling and magnetic flux threading through the system can be tuned, the effect of asymmetry parameter and magnetic flux on this tuning is being explored in Coulomb blockade regime. The presence of the Coulomb blockade due to on-dot Coulomb interaction decreases the width of transmission peak at energy level ɛ + U and by adjusting the magnetic flux the swapping effect in the Fano peaks in asymmetric and symmetric parallel configuration sustains despite strong Coulomb blockade effect.

  8. Blockade of Metallothioneins 1 and 2 Increases Skeletal Muscle Mass and Strength.

    PubMed

    Summermatter, Serge; Bouzan, Anais; Pierrel, Eliane; Melly, Stefan; Stauffer, Daniela; Gutzwiller, Sabine; Nolin, Erin; Dornelas, Christina; Fryer, Christy; Leighton-Davies, Juliet; Glass, David J; Fournier, Brigitte

    2017-03-01

    Metallothioneins are proteins that are involved in intracellular zinc storage and transport. Their expression levels have been reported to be elevated in several settings of skeletal muscle atrophy. We therefore investigated the effect of metallothionein blockade on skeletal muscle anabolism in vitro and in vivo We found that concomitant abrogation of metallothioneins 1 and 2 results in activation of the Akt pathway and increases in myotube size, in type IIb fiber hypertrophy, and ultimately in muscle strength. Importantly, the beneficial effects of metallothionein blockade on muscle mass and function was also observed in the setting of glucocorticoid addition, which is a strong atrophy-inducing stimulus. Given the blockade of atrophy and the preservation of strength in atrophy-inducing settings, these results suggest that blockade of metallothioneins 1 and 2 constitutes a promising approach for the treatment of conditions which result in muscle atrophy.

  9. Coulomb blockade and Coulomb staircase behavior observed at room temperature

    NASA Astrophysics Data System (ADS)

    Uky Vivitasari, Pipit; Azuma, Yasuo; Sakamoto, Masanori; Teranishi, Toshiharu; Majima, Yutaka

    2017-02-01

    A single-electron transistor (SET) consists of source, drain, Coulomb island, and gate to modulate the number of electrons and control the current. For practical applications, it is important to operate a SET at room temperature. One proposal towards the ability to operate at room temperature is to decrease Coulomb island size down to a few nanometres. We investigate a SET using Sn-porphyrin (Sn-por) protected gold nanoparticles (AuNPs) with 1.4 nm in core diameter as a Coulomb island. The fabrication method of nanogap electrodes uses the combination of a top-down technique by electron beam lithography (EBL) and a bottom-up process through electroless gold plating (ELGP) as our group have described before. The electrical measurement was conducted at room temperature (300 K). From current–voltage (I d–V d) characteristics, we obtained clear Coulomb blockade phenomena together with a Coulomb staircase due to a Sn-por protected gold NP as a Coulomb island. Experimental results of I d–V d characteristics agree with a theoretical curve based on using the orthodox model. Clear dI d/dV d peaks are observed in the Coulomb staircase at 9 K which suggest the electron transports through excited energy levels of Au NPs. These results are a big step for obtaining SETs that can operate at room temperature.

  10. Primary combined androgen blockade in localized disease and its mechanism.

    PubMed

    Namiki, Mikio; Kitagawa, Yasuhide; Mizokami, Atsushi; Koh, Eitetsu

    2008-04-01

    In spite of clinical practice guidelines such as NCI-PDQ - in which primary androgen deprivation therapy (PADT) is not recommended as the primary treatment for localized prostate cancer - many patients have been treated with PADT. One of the reasons is that urologists themselves permit patients' desire because they know the effectiveness of PADT for some patients in their experiences. In this review we demonstrate basic mechanisms and the clinical efficacy of primary combined androgen blockade (PCAB) for localized or locally advanced prostate cancer. Then we discuss which patients are candidates for PCAB, and show that more than 30% of low- or intermediate-risk localized prostate cancers could be controlled in the long term with only PCAB. Short-term or intermittent PADT could not be recommended because of the possibilities of changing the character of the cancer cells by incomplete androgen ablation. We propose algorithms for the treatment of localized prostate cancer not only in low- and intermediate-risk groups but also in the high-risk group.

  11. Long term Survival with CTLA-4 blockade Using Tremelimumab

    PubMed Central

    Eroglu, Zeynep; Kim, Dae Won; Wang, Xiaoyan; Camacho, Luis H.; Chmielowski, Bartosz; Seja, Elizabeth; Villanueva, Arturo; Ruchalski, Kathleen; Glaspy, John A.; Kim, Kevin B.; Hwu, Wen-Jen; Ribas, Antoni

    2016-01-01

    Purpose One of the hallmarks of cancer immunotherapy is the long duration of responses, evident with cytokines like interleukin-2 or a variety of cancer vaccines. However, there is limited information available on very long term outcomes of patients treated with anti-CTLA-4 antibodies. Tremelimumab is an anti-CTLA-4 antibody of Ig G2 istoype initially tested in patients with advanced melanoma over 12 years ago. Methods We reviewed the outcomes of patients with advanced melanoma enrolled in four phase 1 and 2 tremelimumab trials at two sites to determine response rates and long-term survival. Results A total of 143 patients were enrolled at two institutions from 2002 to 2008. Tremelimumab administration varied between a single dose of 0.01 mg/kg and 15 mg/kg every 3 months. Median overall survival was 13 months (95% CI, 10–16.6), ranging from less than a month to 12+ years. An objective response rate of 15.6% was observed, with median duration of response of 6.5 years, range of 3 to 136+ months. The Kaplan-Meier estimated 5 year survival rate was 20% (95% CI, 13–26%), with 10 and 12.5 year survival rates of 16% (95% CI, 9–23%). Conclusions CTLA-4 blockade with tremelimumab can lead to very long duration of objective anti-tumor responses beyond 12 years. PMID:26364516

  12. Novel pharmacological approaches for the antagonism of neuromuscular blockade.

    PubMed

    Pic, Lisa C

    2005-02-01

    Gamma cyclodextrin and purified plasma cholinesterase are 2 novel pharmacological agents being investigated as to their suitability for antagonism of neuromuscular blockade. Both of these agents are devoid of cholinergic stimulation and the accompanying side effects because their action is independent of acetylcholinesterase inhibition. Gamma cyclodextrin antagonizes the steroidal neuromuscular blocker rocuronium via the chemical encapsulation of the molecule forming a "host-guest" complex through van der Waals and hydrophobic interactions in the plasma. Encapsulation decreases plasma drug concentrations, shifting the neuromuscular blocking drug molecules from the neuromuscular junction back to the plasma compartment resulting in a rapid recovery of the neuromuscular function. Org 25969, a modified gamma cyclodextrin, will antagonize profound neuromuscular block induced by rocuronium in approximately 2 minutes. A commercial preparation of purified human plasma cholinesterase has been shown to be effective in reversing succinylcholine or mivacurium-induced block. Administration of exogenous plasma cholinesterase also has been shown to be effective in antagonizing mivacurium-induced neuromuscular b