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)

Angiotensin II (Ang II) binding sites were characterized in primary cultures of bovine brain microvessel endothelial cell (BMEC) monolayers. Binding of [3H]Ang II to BMECs was time dependent and saturable. Scatchard plot analysis of dose-dependent [3H]Ang II binding revealed a single population of binding sites (Kd = 3.1 nM, Bmax = 52 fmoles/mg protein). Sarathrin, an Ang II antagonist, and saralsin, a partial agonist, inhibited [3H]Ang II binding to BMEC monolayers, whereas two unrelated peptides, bradykinin and arginine-vasopressin, had no effect on the specific binding of [3H]Ang II. At 37 degrees C, [3H]Ang II was internalized in BMECs and this uptake appeared to be saturable. Nanomolar concentrations of Ang II and saralasin stimulated [3H]thymidine uptake in serum-free starved BMEC monolayers, corresponding to an increase in DNA synthesis. On the other hand, sarathrin had no effect on [3H]thymidine uptake. The affinity of the single population of Ang II of binding sites was consistent with the concentration range of Ang II actions demonstrated in several cell types including BMECs. The Ang II-mediated actions on DNA synthesis suggest that this peptide-hormone may possess growth regulating properties in BMECs through either surface or internal site interactions. Collective findings support the complex nature of Ang II in regulating vascular and nonvascular cell growth and permeability characteristics.
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PMID:Some characteristics of specific angiotensin II binding sites on bovine brain microvessel endothelial cell monolayers. 192 32

Several changes in neuroendocrine activity follow failure of cardiac function to satisfy peripheral requirements and contribute to the clinical syndromes of heart failure. Afferent pathways are poorly understood and triggers are both central and peripheral, involving attenuation of atrial and arterial baroreceptor activity. Efferent sympathetic activity is generally increased with resulting vasoconstriction, but responses are organ-specific and differ among heart, kidney, lung and skeletal muscle. Changes in cardiac sympathetic activity are inadequately understood. Enhanced cardiac norepinephrine spillover contrasts with reduced tissue concentration and impaired activity of synthetic enzymes and neuronal catecholamine uptake. Beta-receptor down-regulation further complicates overall adrenergic responsiveness and the balance between enhancement of contractile function and reduction in arrhythmia threshold. Activation of the renin-angiotensin system is potentiated by the sympathetic nervous system and may contribute to vasoconstrictor hyporesponsiveness. Angiotensin II may in turn facilitate the central and peripheral effects of sympathetic activation and the release of vasopressin from the pituitary. Our understanding of the role of vasodilator peptides in heart failure remains rudimentary. It is likely that vasoconstrictor neuroendocrine response adversely influences optimal cardiac function in heart failure and may promote arrhythmogenesis. The neuroendocrine response in individual organs, however, requires intensive study.
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PMID:Neuroendocrine activation in congestive heart failure. 202 Nov 17

Angiotensin II, when given in low doses, raises blood pressure slowly. When tested in vitro on vascular smooth muscle cells, it has mitogenic and trophic effects; it is not known if it has these effects in vivo. Our purpose was to determine whether vascular hypertrophy develops during slow pressor infusion of angiotensin II and, if so, whether it is pressure induced. Three experiments were done in rats infused subcutaneously with angiotensin II (200 ng/kg/min) by minipump for 10-12 days. Experiment 1: Angiotensin II gradually raised systolic blood pressure (measured in the tail) from 143 +/- 2 to 208 +/- 8 mm Hg (mean +/- SEM), significantly suppressing plasma renin and increasing threefold (NS) plasma angiotensin II. There was no loss of peptide in the pump infusate when tested at the end of the experiment. Experiment 2: In the perfused mesenteric circulation, vasoconstrictor responses to norepinephrine, vasopressin, and KCl were enhanced in rats given a slow pressor infusion of angiotensin II, but sensitivity of responses was not altered. This combination of changes suggests that vascular hypertrophy develops during slow pressor infusion of angiotensin II. Experiment 3: Vessel myography was done after angiotensin II infusion with and without a pressor response. Angiotensin II raised systolic blood pressure, increased heart weight, and produced myographic changes of vascular hypertrophy in the mesenteric circulation, increasing media width, media cross-sectional area, and media/lumen ratio. Hydralazine given with angiotensin II prevented the rise of pressure and the cardiac effect but not the vascular changes. Two-way analysis of variance showed that angiotensin II significantly increased media width, media cross-sectional area, and media/lumen ratio, all independent of hydralazine. Thus, although hydralazine inhibits the pressor and cardiac effects of angiotensin II, suggesting a pressor mechanism for the cardiac change, it does not inhibit structural vascular change, which suggests that at least part of the effect has a non-pressor mechanism.
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PMID:Angiotensin II causes vascular hypertrophy in part by a non-pressor mechanism. 202 7

Previous studies have shown that vascular endothelial cells exhibit a highly active Na-K-Cl cotransport system that is regulated by a variety of vasoactive hormones and neurotransmitters, suggesting that the cotransporter may play an important role in endothelial cell function. In this study, the regulation of endothelial cell Na-K-Cl cotransport was further investigated by probing the stimulus-transfer pathway by which vasoactive agents stimulate the cotransporter. Specifically, three peptides previously shown to stimulate cotransport activity (angiotensin II, vasopressin, and bradykinin) were evaluated. Na-K-Cl cotransport was assessed in cultured bovine aortic endothelial cells as bumetanide-sensitive K+ influx. Stimulation of Na-K-Cl cotransport by angiotensin II, vasopressin, or bradykinin was found to be reduced either by removal of extracellular Ca2+ or by treatment of the cells with 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate or 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. In addition, the calmodulin antagonist W-7 was found to prevent stimulation of endothelial cell Na-K-Cl cotransport by the three peptides. These findings suggest that regulation of endothelial cell cotransport by these vasoactive peptides may be both Ca(2+)- and calmodulin-dependent. Angiotensin II, vasopressin, and bradykinin were also found to elevate phosphatidylinositol hydrolysis in the cultured endothelial cells. Thus, the possibility that regulation of endothelial Na-K-Cl cotransport by these vasoactive peptides also involves diacylglycerol activation of protein kinase C was investigated. A 10-min exposure of the endothelial cells to low doses of phorbol 12-myristate 13-acetate was found to reduce Na-K-Cl cotransport whether in the presence or absence of angiotensin II, vasopressin, or bradykinin. However, down-regulation of protein kinase C by a 40-h exposure to higher doses of the phorbol ester was found to elevate Na-K-Cl cotransport activity under both control and agonist-stimulated conditions, indicating that activation of protein kinase C results in inhibition of endothelial cell Na-K-Cl cotransport. Thus, protein kinase C activation may serve as negative feedback in the stimulus-transfer pathway by which these agonists regulate endothelial cell Na-K-Cl cotransport.
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PMID:Endothelial cell sodium-potassium-chloride cotransport. Evidence of regulation by Ca2+ and protein kinase C. 205 Jun 66

Experiments were carried out in conscious, unrestrained, male rats to evaluate possible interactions between brain prostanoids and the brain renin-angiotensin system in the control of vasopressin release and in cardiovascular regulation. The intracerebroventricular (icv) administration of prostaglandin D2 (PGD2) resulted in transient increases in the plasma vasopressin concentration (PAVP) and heart rate and a gradual increase in mean arterial blood pressure (MABP). Pretreatment icv with saralasin, an angiotensin II-receptor antagonist, moderately attenuated the vasopressin response to PGD2, but had no effect on the heart rate and blood pressure responses. Angiotensin II icv increased both PAVP and MABP. This vasopressin response was almost completely prevented by prior icv meclofenamate, a cyclooxygenase inhibitor, and the blood pressure response was attenuated. These observations, combined with previous studies of the role of central angiotensin II and central prostanoids in the physiological control of vasopressin release, suggest that there may be important interactions between brain prostanoids and the brain renin-angiotensin system in this control.
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PMID:Interactions between the brain renin-angiotensin system and brain prostanoids in the control of vasopressin secretion. 207 34

Angiotensin II binding sites were demonstrated at discrete nuclei in the brain of three nonhuman primate species by autoradiography, using the agonist ligand, [Sar1]AII. Although there were some differences in location of the binding sites, all three species exhibited a characteristic pattern of distribution in areas related to water intake, vasopressin secretion, and blood pressure regulation through modulation of sympathetic activity. Studies in the cynomolgus monkey with the antagonist ligand, [Sar1,Ile8]AII, which localizes in pathways as well as nuclei, revealed novel regions of binding including the habenular-interpeduncular pathway, ventral bundle, and XII nerve, in addition to the X nerve. These data indicated that AII, as in other species, has a role in the central homeostatic control mechanisms in the primate.
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PMID:Distribution of angiotensin II receptors in the brain of nonhuman primates. 211 79

A comparison was made of the vascular actions of two hormones having a renal site of action, angiotensin II and vasopressin, using laser Doppler flowmetry to measure perfusion of the cortical and papillary regions of the kidney. Angiotensin II infusion caused dose-related increases in blood pressure and reductions in cortical perfusion, the latter responses being potentiated in the presence of the converting enzyme inhibitor, cilazapril. However, angiotensin II had no effect on papillary perfusion either before or following cilazapril. The reasons for this differing vasoconstrictor ability of angiotensin II at the cortex and papilla are unclear, but it could be due to medullary generation of prostaglandin or bradykinin. Administration of equipressor doses of vasopressin caused graded reductions in both cortical and papillary perfusions, and subsequent cilazapril significantly enhanced the papillary responses. This study demonstrates that the regulation of blood flow through the different regions of the kidney can be differentially regulated by the peptide hormones angiotensin II and vasopressin.
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PMID:The effect of angiotensin II and vasopressin on renal haemodynamics. 214 94

A 62-year-old man with pneumonia and left flank pain had a clinical syndrome of hyponatremia, hypotension, dehydration, and high urinary sodium excretion in the presence of a normal glomerular filtration rate. The plasma level of antidiuretic hormone was relatively high despite decreased serum osmolality. Thyroid function and excretion of glucocorticoid and sex steroids were normal. The serum aldosterone level was very low despite elevated plasma renin activity. Angiotensin II failed to stimulate any secretion of aldosterone, despite the occurrence of a progressive rise in blood pressure. On the other hand, rapid ACTH administration increased both serum aldosterone and cortisol. The patient showed no effective response to increased salt intake, but large doses of mineralocorticoid resulted in a normal serum sodium level without dehydration. Subsequently, he suffered cardiac arrest secondary to ventricular tachycardia. Postmortem examination showed well differentiated adenocarcinoma in the left pleura and an intact, histologically normal adrenal zona glomerulosa and kidney. This is the first reported case of a critically ill patient with hyponatremia caused by hyperreninemic hypoaldosteronism possibly due to angiotensin II insensitivity and tubular unresponsiveness to mineralocorticoid.
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PMID:Hyponatremia and hyperreninemic hypoaldosteronism in a critically ill patient: combination of insensitivity to angiotensin II and tubular unresponsiveness to mineralocorticoid. 217 79

Preeclampsia is characterized by increased vascular sensitivity to Angiotensin II, endothelial damage, and arteriolar spasm. We hypothesize that these events may be initiated by stimulation of V1 receptors. V1 receptors are normally activated by vasopressin. However, V1 receptors may be activated by the nonapeptide formed when vasopressin is metabolized by the placental enzyme--vasopressinase. This enzyme, found only in humans, cleaves the ring structure of vasopressin, but leaves the N-terminal end, the locus of pressor activity, intact. The resulting molecule, vasopressinase altered vasopressin (VAV), may be present in greater concentration in preeclamptic women and over the months of the second trimester initiate the cascade of pathophysiologic changes resulting in toxemia.
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PMID:A proposed relationship between vasopressinase altered vasopressin and preeclampsia. 219 37

Stimulation of the renin angiotensin system, catecholamines and antidiuretic hormone causes prominent vasoconstriction in severe heart failure. Angiotensin converting enzyme inhibitors reverse these effects, and thus ameliorate cardiac function and reduce mortality in severe heart failure. Angiotensin II is an important regulator of renal function in diseases with renal hypoperfusion, and treatment with angiotensin converting enzyme inhibitors may cause a serious decrease in glomerular filtration and hyperkalemia. Asymptomatic heart failure, acute heart failure and acute myocardial infarction are areas where angiotensin converting enzyme inhibitors may prove beneficial in the future.
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PMID:[Treatment of heart failure with angiotensin converting enzyme inhibitors]. 221 71


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