Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The non-contractile aortic smooth muscle cell line A7r5 was used to study the membrane events involved in the effect of vasoconstrictor peptides. Whole-cell voltage-clamp and membrane potential recording techniques were used to demonstrate the contribution of an increased Cl- conductance to the late depolarization induced by endothelin-1 and vasopressin. During cell-attached patch recording with N-methyl-D-glucamine in the pipette, bath application of endothelin or vasopressin induced single-channel inward currents in the following minutes. The current/potential (I/V) curve of the most frequently observed channel type--a small conductance Cl- (SCl) channel--reversed near the cell membrane potential and showed a single-channel conductance of 1.8 pS for inward currents. After patch excision in an extracellular solution containing CaCl2 (2 mM), the frequency of SCl channel openings increased. Patch excision in the absence of peptide stimulation also produced this channel activity. Replacement of CaCl2 by a Ca2+ chelator on the intracellular face of a patch reversibly inhibited the channel activity, indicating that these SCl channels are Ca(2+)-activated Cl- channels. The single-channel I/V characteristic showed outward rectification above +50 mV. An analysis of the gating kinetics of the SCl channel is given. Another channel type was recorded less frequently after peptide stimulation. It had a lower conductance (1.0-1.3 pS) and slower kinetics and was designated a very small conductance Cl- channel. It is concluded that activation of two types of Cl- channels (at least one of which is Ca2+ dependent) is involved in the late depolarization produced by vasoconstrictor peptides in vascular smooth muscle cells of the aortic cell line A7r5.
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PMID:Endothelin and vasopressin activate low conductance chloride channels in aortic smooth muscle cells. 827 71

The effects of endothelin-1 (ET-1) on protein synthesis and phosphoinositide (PI) hydrolysis were investigated in ventricular myocytes isolated by collagenase digestion of adult rat hearts. The maximum stimulation of protein synthesis by ET-1 was about 35% and the EC50 value was about 0.3 nM. The stimulation was exerted at the translational stage since it was insensitive to inhibition by actinomycin D. The maximum stimulation of PI hydrolysis by ET-1 as measured by the formation of [3H]inositol phosphates was about 11-fold and the EC50 value was about 0.7 nM. The ET-1 analogue sarafotoxin-6b stimulated protein synthesis by a maximum of 27% and stimulated PI hydrolysis about 8- to 9-fold. The EC50 values were 1.6 nM and 0.6 nM, respectively. Other endothelins stimulated protein synthesis and PI hydrolysis in the following order of potency: ET-1 approximately ET-2 > ET-3. This order of potency suggests that the stimulation of both protein synthesis and PI hydrolysis is mediated through the ETA receptor. Although both angiotensin II and [Arg]vasopressin stimulated PI hydrolysis significantly, the stimulation was less than 60%, i.e., much less than the stimulation by ET-1 and its analogues. Neither insulin nor substance P stimulated PI hydrolysis. Stimulation of protein synthesis by ET-1 and its analogues correlated strongly with the stimulation of PI hydrolysis and we suggest that the stimulation of protein synthesis may be dependent on the stimulation of PI hydrolysis. We hypothesize that the mechanism may involve a protein kinase C-mediated increase in intracellular pH.
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PMID:Stimulation of adult rat ventricular myocyte protein synthesis and phosphoinositide hydrolysis by the endothelins. 838 85

This study was designed to determine plasma endothelin-1 levels in patients with essential hypertension and diabetes mellitus. Endothelin immunoreactivity was measured in normal controls (n = 30), mild-moderate essential hypertensives (n = 25), Type II diabetic normotensives (n = 25) and hypertensive patients (n = 20). In addition, in ten patients of each group we investigated the relationships of endothelin with other vasoactive hormones. Plasma endothelin concentrations were similar in healthy controls, in essential hypertensives and in diabetic patients with or without hypertension, averaging 8.23 +/- 1.68 pg/ml, 7.7 +/- 1.1 pg/ml, 5.05 +/- 0.94 pg/ml, 7.88 +/- 1.41 pg/ml, respectively. No correlations were observed between endothelin and concentrations of plasma renin activity, aldosterone, catecholamines, atrial natriuretic peptide and arginine-vasopressin. The present study suggests that Type II diabetic patients with or without essential hypertension do not have demonstrably higher values of plasma endothelin than essential hypertensives or healthy subjects.
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PMID:Plasma endothelin in essential hypertension and diabetes mellitus. 841 Sep 22

The effects of DuP 753 and EXP 3174, nonpeptide angiotensin II type 1 antagonists, on responses to angiotensin II were investigated in the hindquarters vascular bed of the cat. Under constant flow conditions, injections of angiotensin II into the hindquarters perfusion circuit elicited dose-dependent increases in perfusion pressure. Responses to the peptide were stable with respect to time, did not exhibit tachyphylaxis, and 2-n-butyl-4-chloro-5-hydroxymethyl-1-[2'-(1H-tetrazol-5-yl)biph eny l-4-yl]methyl]methyl]imidazole (DuP 753) in doses of 1 and 2.5 mg/kg decreased vasoconstrictor responses to angiotensin II in a competitive manner, with a longer duration of action at the higher dose. DuP 753 had no significant effect on vasoconstrictor responses to vasopressin, norepinephrine, neuropeptide Y or 11 alpha,6 alpha-epoxymethano-9 alpha,11 alpha-dideoxy-prostaglandin F2 alpha, on biphasic responses to endothelin-1, or on vasodilator responses to acetylcholine. 2-n-Butyl-4-chloro-1-[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]im idazole-5-carboxylic acid (EXP 3174) also decreased responses to angiotensin II without altering responses to norepinephrine, vasopressin, U46619 or endothelin-1. The inhibitory effect of EXP 3174 was surmountable; however, large doses of angiotensin II were required, and the blockade was long in duration. The effects of DuP 753 and EXP 3174 on responses to angiotensin II and angiotensin III were similar, and when EXP 3174 was administered in doses of 0.1 and 0.05 mg/kg i.v., the blockade was overcome and the dose-response curves for angiotensin II were shifted to the right in a parallel manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Analysis of the inhibitory effects of DuP 753 and EXP 3174 on responses to angiotensin II in the feline hindquarters vascular bed. 845 Apr 54

The regulatory systems of endogenous endothelin-1 (ET-1) production from intact tissues and the effects of produced ET-1 on vascular tonus by a closed circuit perfusion system of rat mesenteric artery were investigated. It was demonstrated that ET-1 is released from intact mesenteric arterial beds from Wistar rats both under basal conditions and after stimulation with arginine-vasopressin (AVP) (10(-10)-10(-9) M). Furthermore, AVP (10(-10)-10(-9) M) markedly and dose-dependently induced the expression of prepro ET-1 mRNA in the mesenteric arterial beds. Increased release of ET-1 by AVP may contribute to maintaining vascular tonus. Concomitant addition of actinomycin D inhibited the increased expression of prepro ET-1 mRNA and reduced the amount of immunoreactive ET-1 found during the 6-hour perfusate from AVP (10(-10) M)-stimulated and -unstimulated tissues.
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PMID:Arginine-vasopressin increases the release of ET-1 into perfusate of rat mesenteric artery. 846 Oct 20

We studied the inhibitory effects of heparin on basal and agonist-induced endothelin-1 biosynthesis and release from cultured bovine endothelial cells. Heparin dose-dependently and similarly inhibited endothelin-1 release, inositol trisphosphate production, and intracellular free Ca2+ levels stimulated by thrombin. Hirudin fragment had an inhibitory effect on thrombin-induced endothelin-1 release, whereas anti-thrombomodulin antibody had no effect. Heparin completely blocked phorbol ester-induced endothelin-1 release, whereas it had a partial inhibitory effect on endothelin-1 release stimulated by angiotensin and vasopressin. Northern blot analysis using complementary DNA for bovine preproendothelin-1 as a probe revealed that heparin reduced not only the basal but also the stimulated expression of preproendothelin-1 messenger RNA by thrombin and phorbol ester. These data suggest that heparin, in addition to its antithrombin effect, has an inhibitory effect on the biosynthesis and release of endothelin-1, possibly by inhibiting protein kinase C-dependent pathway.
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PMID:Heparin has an inhibitory effect on endothelin-1 synthesis and release by endothelial cells. 847 44

We investigated the effect of endothelin-1 on relaxation responses induced by vasodilator substances in canine middle cerebral arteries to better understand regulation of cerebrovascular tone and its potential impact on mechanism of cerebral vasospasm. Endothelin-1 elicited concentration-dependent contractions in helical strips of canine cerebral arteries (EC50; 4.62 x 10(-9) M). Pretreatment with 10(-9) M endothelin-1 significantly reduced endothelium-dependent relaxation elicited by substance P and endothelium-independent relaxations by nitroglycerin, prostaglandin I2, and KCl. Although endothelin-1 in a lower concentration (10(-10) M) did not affect these endothelium-independent relaxations, it did inhibit endothelium-dependent relaxation caused by substance P. A low concentration (10(-10) M) of endothelin-1 also significantly reduced endothelium-dependent relaxation of canine mesenteric arteries induced by acetylcholine. Other vasoconstrictor peptides such as angiotensin-II and vasopressin did not inhibit endothelium-dependent and -independent relaxations. These results indicate that endothelin-1 not only produces cerebral vasoconstriction but also interferes with vasodilator mechanisms and that endothelium-dependent vasodilation is more sensitive to the inhibitory effect of endothelin-1 than endothelium-independent vasodiltion.
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PMID:Suppression of cerebral vasodilation with endothelin-1. 853 97

We have characterized a specific binding site for angiotensin IV on bovine aortic endothelial cell membranes. Pseudo-equilibrium studies at 37 degrees C for 2 h have shown that this binding site recognizes angiotensin IV with a high affinity (Kd = 0.71; average of two experiments that yielded values of 0.71 and 0.72 nM). The binding site is saturable and relatively abundant with a maximal binding capacity of 0.59 pmol/mg protein (average of two experiments that yielded values of 0.39 and 0.78 pmol/mg of protein). Non-equilibrium kinetic analyses at 37 degree C revealed a calculated Kd of 59 pM (average of two experiments that yielded values of 67 and 50 pM). The binding site displays a high affinity for angiotensin receptors AT1 or AT2. An analysis of specificity showed that the binding site displays a high affinity for angiotensin IV, low affinities for angiotensin II, [Sar1, Val5, Ala8]angiotensin II and does not recognize L-158,809 (5,7-dimethyl-2-ethyl-3-[(2'-(1 H-tetrazole-5-yl)[1,1'-biphenyl]-4-yl)methyl]-3H-imidazo[4, 5-beta]pyridine H2O) and PD 123319 (1-[4-dimethylamino)3-methylphenyl]methyl-5-(diphenylacetyl) 4,5,6,7-tetrahydro-1 H-imidazo[4,5-c]pyridine-6-carboxylic acid). A few unrelated hormones (bradykinin, [Arg8] vasopressin, endothelin-1, atrial natriuretic factor, isoproterenol and adrenocorticotropic hormone) were unable to inhibit any 125I-angiotensin IV binding. The affinities of different structural analogues of angiotensin IV revealed that the N-terminal position is critical for receptor recognition and the C-terminal proline is also important. GTP gamma S and polyvinyl sulfate did not affect the binding, suggesting that the receptor is not coupled to a G-protein. The divalent cations Mg2+ and Ca2+ were shown to diminish the binding of 125I-angiotensin IV. Cross-linking of 125I-angiotensin IV to bovine aortic endothelial cell membranes in the presence of disuccinimidyl suberate, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a major band of 186 +/- 12 kDa. The presence in high concentration of this angiotensin binding site on aortic endothelial cells suggest the existence of a novel mechanism involved in the control of vascular tone or vascular permeability.
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PMID:Characterization of a binding site for angiotensin IV on bovine aortic endothelial cells. 856 70

The testis is a complex organ in which local control is achieved by signalling between its constituent cells. Herein we describe the responses of cultured rat testicular cells and a mouse Sertoli cell-line to stimulation by endothelin and ATP, and elsewhere we have shown that rat peritubular myoid cells possess phosphoinositidase C-coupled V1a-vasopressin receptors identical to those of liver (Howl, J. et al, 1995, Endocrinology 136: 2206-2213). 1. Peritubular myoid cells from pre-pubertal rats responded through ETA receptors with PtdIns(4,5)P2 hydrolysis [EC50 for endothelin-1 (ET-1) approximately 0.4 nM], elevation of intracellular [Ca2+], and tyrosine phosphorylation of a variety of cellular proteins. They also showed enhanced adenylate cyclase activity, with an EC50 for ET-1 of approximately 3 nM, also through ETA receptors. Pharmacological elevation of [cAMP] did not immediately change the ET-1-stimulated formation of inositol phosphates, but attenuated the response after several hours. 2. Pre-pubertal rat Sertoli cells showed no detectable responses to ET-1, but responded to FSH with elevated [cAMP] and to ATP with PtdIns(4,5)P2 hydrolysis. PtdIns(4,5)P2 hydrolysis was equally responsive to ATP and UTP, and so appears to be activated by P2U-purinergic receptors. This response was enhanced by protein kinase C inhibition and attenuated by PKC activation. 3. Despite its lack of effect on rat Sertoli cells in primary culture, ET-1 provoked PtdIns(4,5)P2 hydrolysis in the TM4 murine Sertoli cell line (EC50 approximately 0.6 nM), and this response was negatively regulated by protein kinase C activation. 5. No receptor-stimulated activation of phosphoinositase C was detected in 'germ cell' populations, but the non-specific G protein activator A1F4-provoked inositol phosphate accumulation in these cells, so demonstrating their potential to respond through yet to be identified G protein-coupled receptors with phosphoinositidase C activation. 6. Immunoblotting studies showed the presence in rat testis of phosphoinositidase C-beta 1 and the alpha-subunits(s) of the G-protein(s) Gq and/or G11. These studies show that testicular myoid and Sertoli cells use at least three G protein-coupled receptors (V1a-vasopressins, ETA-endothelin and P2U-purinergic) to signal through phosphoinositidase C activation, that ET-1 can activate multiple signalling pathways in myoid cells, and that the ET-1-stimulated phosphoinositidase C responses of myoid and Sertoli cells have different regulatory characteristics.
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PMID:Inositol lipid-mediated signalling in response to endothelin and ATP in the mammalian testis. 856 25

We studied the cardiovascular effects produced by administration of endothelin-1 (ET-1) into brain nucleic known to affect vasopressin release. In urethane-anesthetized Sprague-Dawley rats, microinjection of ET-1 into the subfornical organ (SFO) resulted in a dose-dependent increase in arterial blood pressure and a decrease in heart rate. These effects were inhibited by previous administration of the ETA receptor antagonist BQ-123 or by intravenous administration of a vasopressin antagonist. In addition, microinjection of ET-1 into the SFO increased plasma levels of vasopressin. In contrast, in the paraventricular nucleus (PVN) of the hypothalamus microinjection of ET-1 evoked a dose-related bradycardia with inconsistent changes in blood pressure. Although the bradycardia was antagonized by intra-PVN administration of BQ-123, the vasopressin antagonist did not affect the changes in heart rate evoked by microinjection of this peptide into the PVN. Overall, these results indicate that the central cardiovascular effects of ET-1 result from activation of several mechanisms, including stimulation of brain centers regulating vasopressin release.
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PMID:Cardiovascular effects of endothelin injected into brain nuclei regulating vasopressin release. 858 51


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