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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Relation between kallikrein-kinin and renin-angiotensin polypeptide blood systems, main regulators of arterial pressure, is considered. Activities of kallikrein, renin and angiotensin-converting enzyme were studied in healthy persons and in patients with various forms of renin-dependent arterial hypertension under conditions of immobility and after physical loading. In dynamics of hereditary-determined hypertension of rats there were studied the effects of bradykinin and angiotensin II on alterations in reactivity of the vascular bed as well as on alterations in lung metabolic functions. A scheme of functionally important relations between the factors of neurohumoral regulation of arterial blood pressure is developed involving direct and reverse interactions between the blood pressure and depressive components of the polypeptide systems.
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PMID:[Physiologically active peptides and the regulation of arterial pressure in normal and pathological states]. 608 32

Several forms of the polypeptide atrial natriuretic factor (ANF) have been isolated recently from rat and human atria and identified; they are probably associated with the secretory granules of atrial tissue. The potent ability of ANFs to increase urine sodium content is mediated by their direct action on the kidney. We report here the high intrinsic activity of a synthetic replicate of one form of this molecule, ANF(8-33)(ref. 7), to inhibit directly basal aldosterone secretion and its ability to antagonize the stimulatory effects of adrenocorticotropin (ACTH) and angiotensin II (AN-II) on the secretion of aldosterone by rat adrenoglomerulosa cells in vitro. Our results suggest that ANF is of clinical importance in the management of aldosterone-dependent hypertension by modifying the adrenocortical response to endogenous ACTH and AN-II.
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PMID:Inhibition of aldosterone production in the adrenal glomerulosa by atrial natriuretic factor. 609 16

Polypeptides are endogenous agents, involved in the regulation of many physiologic functions and the pathogenesis of several diseases. Polypeptide antagonists form a group of new chemical entities which may provide valid therapeutic agents. Some polypeptides (angiotensin, kinins) are released through the action of proteolytic enzymes (renin, kallikreins) and act as hormones or autacoids; others (substance P, neurotensin) are synthetized by nervous cells to serve as neurotransmitters or neuromodulators. The main homeostatic role of the renin-angiotensin system is to uphold high systemic arterial blood pressure. Overproduction of renin and insufficient checking of renin secretion are among the most common causes of arterial hypertension. Several forms of arterial hypertension (neurovascular, idiopathic) benefit from a reduction in renin-angiotensin system activity. This is achieved either through decreasing renin secretion, by inhibiting conversion of angiotensin I into angiotensin II, or through blocking the peripheral actions (at the receptor sites) of angiotensin II. Renin secretion is very significantly reduced by beta-blocking agents (propranolol); conversion of angiotensin I into angiotensin II is inhibited by teprotide, captopril and their derivatives; peripheral actions of angiotensin II are blocked by saralasin. Bradykinin and related agents produce vasodilation, increase vascular permeability and stimulate pain fibers. Kinins thus reproduce the cardinal features of inflammation and are held to be mediators of the inflammatory reaction. The substance P neuropeptide is found in the brain and bowel; it may act as a transmitter of the sensation of pain at the spinal cord and central nervous system sites. Among other effects outside of the brain, substance P is a potent vasodilator and inhibits renin secretion. Neurotensin is a neuropeptide which produces hypothermia, muscular relaxation and analgesia. Outside of the brain, this peptide is involved in the regulation of gastric secretion, intestinal motility and insulin and glucagon secretion. The vasoactive intestinal peptide, found in certain cholinergic nerve endings, is a large peptide which inhibits gastric secretion, intestinal motility and vascular tone.
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PMID:[Polypeptides and antagonists]. 620 6

The vasoconstrictor effects of serotonin can be explained by (a) activation of serotonergic receptors on vascular smooth muscle, (b) activation, directly or indirectly, of postjunctional alpha-adrenoceptors, and (c) amplification of the response to other vasoactive agonists. Vasoconstrictor responses to serotonin may play a role in the etiology of vasospasm and in the maintenance of the augmented peripheral resistance in arterial hypertension. The vasodilator effects of serotonin can be caused by (a) inhibiting vascular smooth muscle directly, (b) releasing other inhibitory substances, such as vasoactive intestinal polypeptide, (c) inhibiting adrenergic neurotransmission, and (d) triggering of endothelium-dependent relaxation.
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PMID:Serotonin and arterial vessels. 620 51

During the induction phase of low-renin, one-kidney, one-wrapped hypertension in rabbits,serum angiotensin converting enzyme (ACE) activity is depressed and correlates inversely with the degree of necrotic arterial disease that develops. Responses to the vasoactive polypeptides, bradykinin (BK), angiotensin I (AI), angiotensin II (AII), the ACE blocker teprotide, and the AII antagonist 1-sar-8-ile AII were studied. Responses to BK, AII, and AI showed significant changes in both magnitude and duration (recovery time). Recovery time for depressor responses to BK in hypertensive rabbits was approximately three times that in the control period. One-wrapped, two-kidney control rabbits without hypertension-associated arterial disease showed no change in BK recovery time, although serum ACE activity was significantly depressed. In the experimental period BK recovery time correlated directly with the degree of arterial disease and indirectly with the final serum ACE activity. Duration of the pressor responses after AII correlated directly with the degree of arterial disease and indirectly with final serum ACE activity. In untreated hypertensive rabbits the percentage of increases in blood pressure after AI relative to control animals were decreased, and for all hypertensive rabbits' the increase in blood pressure correlated directly with the final serum ACE activity. Long-term treatment with teprotide moderated the hypertension but had little effect on serum ACE activity or the responses to BK, AII, and AI. Short-term infusions of 1-sar-8-ile AII and teprotide caused significant decreases in blood pressure in both the control and experimental periods, although no change in response to either polypeptide occurred. These studies support other evidence that pressor components of the renin-angiotensin system do not sustain the elevation of blood pressure in this form of experimental hypertension. Alterations in response patterns following AII and AI suggest that a vasodepressor system may be altered. In addition, part of the altered response to BK, and possibly AII, appears related to the development of the hypertension-associated arterial disease.
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PMID:Alterations in responses to bradykinin, angiotensin I, and angiotensin II during the induction phase of one-kidney, one-wrapped hypertension and associated arterial disease in rabbits. 624 72

Chronic exposure of rats to cadmium (Cd) in drinking water induced elevated systolic and diastolic blood pressure. Heart rate, however, was lowered, suggesting that the hypertension in these rates may be due to an increase of the total peripheral resistance, possibly involving a central nervous system (CNS) component in Cd-induced hypertension. Urinary kallikrein activity was reduced in the exposed animals and may explain the previously reported antinatriuretic effect of Cd, since renal kallikrein is an enzyme responsible for the synthesis of kallidin, a potent vasodilator and natriuretic polypeptide.
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PMID:Urinary kallikrein and hypertension in cadmium-exposed rats. 690 49

A polypeptide fraction isolated from the urine of normotensive subjects lowers the blood pressure (BP) in a rabbit bioassay (mean BP decrease 33.8% +/- 0.6%, SEM). Patients with primary hypertension exhibit reduced or no activity (mean BP decrease 8.8% +/- 1.2%). In contrast, patients with secondary forms of hypertension show activity like normotensives (mean BP decrease 33.4% +/- 1.0%). The results of the bioassay in the two patient groups correlate well with the family incidence of hypertension (68% and 37% for primary and secondary hypertension respectively). Cases with borderline hypertension fall into two groups; a larger one with vasoactivity inthe bioassay and lower family incidence of hypertension; and a smaller group reacting like patients with primary hypertension. Only the latter group may represent an initial stage of primary hypertension. In normotensive children and young men, an inactive fraction was found in 31% and 28% respectively. These inactive groups had twice the family incidence of hypertension compared to the groups with vasoactivity. These results suggest the existence of a possible genetic marker of primary hypertension and may offer the possibility to detect the disease before its manifestation.
Hypertension
PMID:Defect in the excretion of a vasoactive polypeptide fraction A possible genetic marker of primary hypertension. 694 42

Two siblings with congenital Cushing's syndrome due to bilateral nodular adrenal hyperplasia are described. The older, a boy, presented with severe hypertension and died soon after subtotal adrenalectomy. His sister, who had clitoral enlargement and showed persistent hyponatraemia, had a two-stage total adrenalectomy and is still alive. Investigations in the second case showed grossly elevated urinary cortisol metabolites, 17-oxosteroids and 3 beta-hydroxy-5-ene-steroids. These were not suppressed by dexamethasone, and plasma ACTH was undetectable, indicating that the disorder was not due to excessive ACTH secretion. Cell culture studies on the resected adrenals failed to demonstrate an abnormal pattern of steroid synthesis in vitro, and normal trophic responses were obtained with 1-24 ACTH and monobutyryl cyclic AMP. No stimulation of steroid synthesis was obtained with a range of polypeptide hormones, and the cause of the adrenal hyperplasia remains unknown.
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PMID:Familial congenital Cushing's syndrome due to bilateral nodular adrenal hyperplasia. 730 79

The receptor-associated protein (RAP) specifically associates with gp330 and the low density lipoprotein (LDL) receptor-related protein (LRP), the two newest members of the LDL receptor gene family. Results obtained by ligand blotting, affinity chromatography, and density-gradient sedimentation demonstrate that RAP binds to both receptors with high affinity and that the binding is Ca2+ dependent. RAP also binds heparin and is identical to a mouse heparin binding protein (HBP-44) identified in a teratocarcinoma cell line (F9). While biochemical studies have shown that RAP is present on the cell surface and is an effective inhibitor of ligand binding to gp330 and LRP, immunocytochemical findings indicate that RAP is most abundant in the endoplasmic reticulum lumen and may function in receptor folding and/or trafficking. To facilitate the characterization of RAP's function(s) we have mapped its gp330 and heparin binding sites by performing direct binding studies on fusion proteins representing overlapping domains of RAP. gp330 was found to bind to two separate sites on RAP--i.e., between amino acids 85-148 and 178-248. Binding studies with radiolabeled heparin indicate that the heparin binding site is between amino acids 261 and 323, which is consistent with our previously proposed site (residues 287-306) based on the amphipathic nature of the C terminus of RAP. These data demonstrate that the gp330 and heparin binding sites and the Heymann nephritis pathogenic epitope (amino acids 1-86) demonstrated earlier are represented by distinct domains of the RAP polypeptide.
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PMID:Functional domains of the receptor-associated protein (RAP). 751 26

8-Bromo-guanosine 3':5'-cyclic monophosphate (8-Br-cGMP), an analogue of cyclic guanosine monophosphate (cGMP), induced a time- and dose-dependent enhancement of interleukin-1-induced nitric oxide production in vascular smooth muscle cells. Human atrial natriuretic polypeptide, which stimulates cGMP accumulation in vascular smooth muscle cells, also enhanced interleukin-1-induced nitric oxide release at a concentration of 100 nmol/L. In contrast, coincubation with 10 mumol/L methylene blue, an inhibitor of soluble guanylate cyclase, inhibited interleukin-1-induced nitric oxide release from vascular smooth muscle cells. Furthermore, coincubation with 8-Br-cGMP also enhanced the interleukin-1-induced increase in inducible nitric oxide synthase messenger RNA in vascular smooth muscle cells. However, the enhancement of nitric oxide production induced by 8-Br-cGMP was significantly prevented by coincubation with neutralizing antibody against tumor necrosis factor-alpha. Furthermore, 8-Br-cGMP enhanced the interleukin-1-induced increase in tumor necrosis factor-alpha messenger RNA level in vascular smooth muscle cells. These findings indicate that cGMP may upregulate inducible nitric oxide synthase gene expression through the stimulation of tumor necrosis factor-alpha production in vascular smooth muscle cells. Thus, there may be a positive feedback mechanism between nitric oxide and the cGMP system in vascular smooth muscle cells.
Hypertension 1995 Apr
PMID:cGMP upregulates nitric oxide synthase expression in vascular smooth muscle cells. 753 12


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