Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

PGE1 administered in a single dose of 27 nmol intracerebroventricularly (icv) into the rats under urethane anaesthesia caused a long-lasting increase of the blood pressure and tachycardia. Phenoxybenzamine given 60 min before (20 mg/kg ip) blocked the hypertension and tachycardia evoked by PGE1 icv administration. Moreover, reserpine (10 mg/kg ip) given 24 h before PGE1 injection caused similar effects. Previous degeneration of the central adrenergic neurons (6-hydroxydopamine, 2 x 250 micrograms icv) also reduced both exerted effects by PGE1 icv. From the experiments carried out it results that central cardiovascular effects of PGE1 are due to the intact cerebral neurotransmission. These described effects could be common with direct PGE1 action upon adrenergic receptors from indirect effects due to release of noradrenaline by PGE1 in the central nervous system (CNS) in rats.
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PMID:Central action of PGE1 on the cerebral neurotransmission; the cardiovascular response. 285 31

Platelets provide an accessible and homogeneous cellular system for investigative studies on hypertension. Hypertension-associated abnormalities of cyclic adenosine 3',5'-monophosphate (AMP) metabolism were studied in human platelets. Platelets from hypertensive subjects had an enhanced cyclic AMP accumulation response to prostaglandin E1 (twofold increase in prostaglandin E1 sensitivity). The degree of adenylate cyclase activation in response to both prostaglandin E1 (receptor-mediated) and forskolin (non-receptor-mediated) was greater in hypertensive than normotensive subjects, and prostaglandin E1-stimulated and forskolin-stimulated adenylate cyclase activity correlated directly (r = 0.71, p less than 0.001, n = 26). This finding suggests that the catalytic subunit of the enzyme is the rate-limiting step of this hormonal information transduction. Platelets from hypertensive subjects were more sensitive to epinephrine-induced inhibition of the stimulatory effects of prostaglandin E1 on both cyclic AMP accumulation (fourfold) and activation of cyclic AMP-dependent protein kinase. These findings suggest that the enhanced cyclic AMP metabolic response to prostaglandin E1 in platelets from subjects with established essential hypertension may function as a negative feedback mechanism to protect the cells against calcium overload and to reduce their stimulated participation in hemostatic and thrombotic processes.
Hypertension 1986 Aug
PMID:Enhanced platelet cyclic AMP response to prostaglandin E1 in essential hypertension. 301 95

Renal cortical slices obtained from male New Zealand rabbits were used to investigate the role of adenosine in the regulation of renin release. Isoproterenol produced a significant (p less than 0.01), twofold to threefold increase in renin release, that was both dose-dependent and time-dependent. Addition of either the l-phenylisopropyl or the N6-ethylcarboxamido derivative of adenosine attenuated this stimulation at concentrations as low as 10(-9) M or 10(-8) M, respectively. Higher doses of d-phenylisopropyladenosine (10(-6) M) or adenosine (10(-5) M) were necessary to significantly reduce the beta-adrenergic response (p less than 0.01). Inhibition was absent in slices preincubated with 10(-5) M 8-phenyltheophylline, a concentration that had no effect on either basal or stimulated renin release. The site of inhibition appeared to be distal to beta-adrenergic and prostaglandin receptors since l-phenylisopropyladenosine (10(-8) M) blocked stimulation by selective beta-adrenergic receptor agonists, prenalterol (10(-6) M) or salbutamol (10(-5) M), and by prostaglandin E1. These data suggest that adenosine and its analogues inhibit renin release and that this inhibition may be mediated by a receptor-dependent action on a common point in the pathway leading to release.
Hypertension 1987 Jun
PMID:Inhibition of renin release by analogues of adenosine in rabbit renal cortical slices. 303 78

Elevated levels of a specific renal growth factor, renotropin, have been associated with spontaneous hypertension. To examine this association more closely, we have undertaken the development of a better assay system to characterize and purify renotropin. Sera from rabbits prior to operation (control) and at a specified time after unilateral nephrectomy (uni) were examined for renotropic activity. Comparing the effects of uni to control sera in the same rabbit, significant stimulation of 3H-thymidine incorporation into the DNA of primary rabbit kidney cultures incubated in D-valine medium to eliminate fibroblast growth was noted: at 3 days postoperatively 73% (n = 13), at 7 days 103% (n = 39), at 10 days 130% (n = 31), at 21 days 101% (n = 24), at 42 days 89% (n = 13). All values were at least P less than 0.01. The stimulatory properties were dose-dependent but reached a plateau at high serum concentrations. Comparing CPM/mg protein in uni/control in different concentrations of sera 7 days postoperatively, uni versus control were 67/44 at 5% v/v, 139/72 at 10% v/v, 261/161 at 20% v/v, and 243/136 at 40% v/v. The renotropic effect of uni sera remained after dialysis in incubation medium and after sera were heated in boiling water for 5 minutes. Renal extracts obtained from growing kidneys 7 days postnephrectomy augmented renotropic activity. Atrial natriuretic factor, ouabain, PGF2 alpha, PGE1, and cAMP did not possess renotropic activity. We conclude that the primary rabbit kidney culture assay for renotropin is highly sensitive and will be an important tool to comprehend the role of renotropin in the pathogenesis of hypertension.
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PMID:The rabbit renotropic system. 340 54

In neonates with isolated coarctation of the aorta presenting with acute neonatal heart failure refractory to classical treatment, emergency surgery is associated with a 30% death-rate. We rather suggest to add to treatment a perfusion of prostaglandin E1 in order to dilate the ductus arteriosus and thereby the aortic isthmus. This was performed successfully in 9 of 12 neonates aged 5 to 16 days: coarctation was relieved and heart failure disappeared. As soon as the left ventricle became hyperkinetic again (2 to 6 days later), prostaglandin was discontinued. Coarctation reappeared with either chronic heart failure (3 cases) or severe arterial hypertension (5 cases). Eventually one child recovered without surgery and the other 11 were operated on at an average age of 24 days, with only one death.
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PMID:[Treatment by prostaglandin E1 of isolated coarctations in newborn infants with acute cardiac failure]. 356 40

Fifty-four hypertensive patients with the average BP level of 208 +/- 3.2/125 +/- 2.4 mm Hg were infused 2 doses of PGE. Forty patients received PGE2 in the form of protein (USA) and 14 patients were administered PGE1 in the form of alprostadil (USA). Each patient received on the average 3.5 mg of PGE2 or 0.7 mg of PGE1 during 48 hours. PGE infusion by the devised scheme induced no significant side-effects, was attended by an increase in the diuresis and natriuresis as well as a BP decrease (more pronounced with PGE1) not only in the period of the infusion but also during the 2-3 days following it. The hypotensive effect and BP fall in the orthostatic position were more marked following PGE2 infusion. PGE enhanced the sensitivity of the patients to obsidan, clophelin, hydrochlorothiazide and to a lesser degree to corinfar. Infusion of PGE2 to patients with essential hypertension resistant to hypotensive agents reduced the BP and made it possible to diminish the number of the drugs prescribed and their doses. The hypotensive effect of the drugs administered persisted for up to 5-7 months. It can be expected that repeated infusions of PGE2 every 6 months, will contribute to an alleviation of arterial hypertension, the patient's clinical improvement and the lowering of doses of hypotensive drugs.
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PMID:[Use of series E prostaglandins in the treatment of essential hypertension]. 385 1

Abnormalities of platelet aggregation and cyclic nucleotide metabolism are present in hypertension. We observed a greater increase in the level of cyclic adenosine monophosphate (AMP) after prostaglandin E1 (PGE1) stimulation and a lack of decrease of this cyclic nucleotide by epinephrine in platelets from spontaneously hypertensive rats (SHR) as compared to normotensive rats. The difference in cyclic AMP production between SHR and control rats in response to PGE1 is dependent upon platelet exposure to calcium. Since calcium and cyclic AMP are closely related and are both abnormally regulated in hypertension, we have studied the effect of calcium on adenylate cyclase activity. We show here that two forms of endogenous calcium-dependent proteases (membrane-bound and soluble) stimulate the basal activity and the hormonal responsiveness of adenylate cyclase. The sensitivity of calcium-dependent proteolytic control of adenylate cyclase to very-low concentrations of calcium indicates that the regulation may be physiologically important. Furthermore, calcium exerts a greater influence on platelet adenylate cyclase from SHR than on that from normotensive rats. The adenylate cyclase defect seems to be located in the membrane fraction and may, therefore, result from an increase in the activity of the membrane-bound calcium-protease or may be intrinsic to adenylate cyclase itself. The exact site that is sensitive to proteolysis remains to be established.
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PMID:Calcium-dependent proteolytic stimulation of adenylate cyclase in platelets from spontaneously hypertensive rats. 608 83

Alpha-adrenergic receptor function was measured in platelets from patients with orthostatic hypotension and normotensive controls. Patients with idiopathic orthostatic hypotension (IOH) or multiple system atrophy (MSA) had more alpha-receptors than controls. Patients with IOH, but not MSA, produced less prostaglandin E1 (PGE1)-stimulated cyclic AMP (cAMP) than controls. Patients with sympathotonic orthostatic hypotension (SOH) were similar to controls in receptor number and cAMP production. The percent norepinephrine (NE) inhibition of PGE1-stimulated cAMP production was similar in patients and controls. An increase in alpha-receptor number may result from decreased peripheral NE secretion in IOH and MSA. Increased alpha-receptor number and decreased cAMP production, which accompany essential hypertension, may contribute to the supine hypertension of IOH, and an increase in alpha-receptor number may contribute to the supine hypertension of MSA. SOH patients appear to have no abnormalities of alpha-receptor function.
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PMID:Alpha-adrenergic receptors in orthostatic hypotension syndromes. 608 6

The role of prostaglandins (PGs) in the regulation of blood pressure was analysed from the point of view of vascular reactivity to PGs and also of PG-induced modulation of pressor response. The vasodepressor effect of PGE1 was more sensitive in the patients with essential hypertension than in the normotensive subjects. In the normotensive subjects or in rats, pressor response to norepinephrine was modulated by PGE1, enhanced under treatment with indomethacin, an inhibitor of PG biosynthesis, and suppressed under an infusion of PGE1. These results indicate that pressor response to norepinephrine is modulated by exogenous and endogenous PGs. The PG-induced modulation disappeared after chemical sympathectomy, suggesting that the PG-induced modulation of pressor response is regulated by the sympathetic nervous system. In sympathetic neurotransmission, PGs could play an important role in the regulation of norepinephrine release. Renal content of norepinephrine was reduced under treatment with indomethacin, indicating an enhanced release of norepinephrine and an enhanced turnover of norepinephrine in the kidneys under treatment with indomethacin. These results suggest that a deficient state of PG may enhance the pressor response and norepinephrine release. As there is much evidence indicating that the reduction of PG synthesis in patients and animals with hypertension, vascular reactivity to PGs and PG-induced modulation of pressor response may play significant roles in the regulation of blood pressure and could be causal factors of hypertension.
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PMID:The role of prostaglandins in the regulation of blood pressure with special reference to vascular reactivity. 614 27

A decrease in isoproterenol-stimulated adenylate cyclase activity has been shown in various tissues of hypertensive rats, a finding often associated with decreased beta-adrenoceptor number. The present study was undertaken to investigate whether adenylate cyclase stimulation by other hormones is similarly affected. Adenylate cyclase activity in cerebral microvessels under control conditions and following stimulation by isoproterenol, prostaglandin E1, and the adenosine analog 5'-(N-ethylcarboxamide)-adenosine (NECA) was significantly diminished in deoxycorticosterone acetate (DOCA)-hypertensive rats as compared with control rats, as was adenylate cyclase stimulation by GTP, fluoride, and forskolin. Similar results were obtained in cardiac ventricular membranes, apart from the fact that NECA did not influence adenylate cyclase activity in the heart, either in normotensive or in hypertensive rats. In both the heart preparation and the microvessel preparation, beta-adrenoceptor numbers were reduced in DOCA-hypertensive rats. Because the adenylate cyclase data also pointed to functional alteration at the guanine nucleotide regulatory site of the adenylate cyclase complex, the influence of DOCA hypertension on receptor-adenylate cyclase coupling was investigated by competition studies for beta-adrenoceptor binding. In ventricular membranes prepared from DOCA-hypertensive rats, the isoproterenol competition curve for [125I]iodocyanopindolol binding was only slightly altered in the presence of guanylyl imidodiphosphate (50 microM), in contrast to normotensive control rats, in which it was shifted to the right and became significantly steeper. These results are suggestive of decreased guanine nucleotide sensitivity of adenylate cyclase-coupled receptors in DOCA hypertension.
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PMID:The cardiac and brain microvessel adenylate cyclase system in deoxycorticosterone acetate-hypertensive rats. 620 Jul 23


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