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)

The change in tonic renal efferent sympathetic nerve activity (RSNA) was studied during the rapid fall in mean arterial pressure (MAP) after surgical reversal of two-kidney, one clip hypertension in rats (RHR). Controls used were intact RHR exposed to the same fall in MAP induced by slow infusion of sodium nitroprusside. Within 2 h after declipping, MAP had fallen from 191 +/- 9 mmHg to 106 +/- 8 mmHg. During this decline in pressure, the reflex increase in RSNA, ordinarily following a decrease in pressure, was clearly suppressed; after a short and transient initial increase, RSNA was below the control level. In comparison, upon vascular dilatation with sodium-nitroprusside, the same fall in MAP was accompanied by a 117 +/- 30% increase in RSNA (P less than 0.01). Thus, the rapid normalization of MAP after reversal of renovascular hypertension involves a mechanism that exerts a suppressive action on the efferent sympathetic activity.
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PMID:Suppression of the sympathetic nerve activity after surgical reversal of two-kidney, one clip hypertension in rats. 659 81

Arachidonic acid (AA)-induced pressor response and production of thromboxane YXB2, the stable metabolite of TXA2, prostaglandin (PG)-like substance (PLS) and 6-keto-PGF1 alpha the stable metabolite of prostacyclin (PGIs), were studied using isolated, perfused kidneys of 6- and 18-week old spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY), two-kidney, one clip hypertensive rats (RHR) and DOCA/salt hypertensive rats (DOCA/salt HR). The AA-induced pressor response and release of TXB2 were highest in the 6-week old SHR, whereas, the release of PLS and 6-keto-PGF 1 alpha was marked in the 18-wek old SHR and the established hypertensive stages of both RHR and DOCA/salt HR. In the kidneys of SHR and WKy, exogenous TXA2 induced a severe vasoconstriction and there was a positive correlation between the AA-induced pressor response and the release of TXB2 or PLS. Thus, the initiation of hypertension in SHR may follow an accelerated synthesis of TXA2 against PGI2 in response to stimuli which induce a release of AA.
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PMID:Enhanced thromboxane A2 biosynthesis in the kidney of spontaneously hypertensive rats during development of hypertension. 722 52

The antihypertensive properties of a new long-acting, angiotensin-I-converting enzyme (ACE) inhibiting agent, (2S,3aS,7aS)-1-(N2-nicotinoyl-L-lysyl-gamma-D-glutamyl) octahydro-1H-indole-2-carboxylic acid (CAS 116662-73-8, DU-1777), were investigated orally in various experimental models of hypertension in comparison to a standard ACE inhibitor, lisinopril. The hypotensive potency of DU-1777 was not as marked as that of lisinopril in renin-dependent hypertensive models, i.e., two-kidney one-clip renal hypertensive rats (2K-1C RHR) (ED-20mmHg: 3.1 versus 1.0 mg/kg) or two-kidney two-clip renal hypertensive dogs (2K-2C RHD) (ED-20 mmHg: 2.5 versus 1.0 mg/kg), though the actions of the two drugs were both long-lasting and dose-related. When spontaneously hypertensive rats (SHR) were used, however, DU-1777 was as active as lisinopril (ED-20 mmHg: 17.9 versus 13.6 mg/kg). The most distinguishing results with DU-1777 were its hypotensive effects in renin-independent hypertensive models. In contrast to lisinopril, the drug produced a sustained and dose-related hypotensive effect in DOCA salt hypertensive rats (DOCA-HR) and one-kidney one-clip renal hypertensive rats (1K-1C RHR). There exists an inconsistency between the long duration of the agent's hypotensive action in all tested hypertensive models and its short duration of ACE inhibiting activity as demonstrated both in vivo and ex vivo. The sustained antihypertensive action of DU-1777 cannot be reasoned solely with respect to ACE inhibition, suggesting some additional mechanisms of action yet to be defined.
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PMID:Antihypertensive properties of a new long-acting angiotensin converting enzyme inhibitor in renin-dependent and independent hypertensive models. 757 46

The antihypertensive activity of quinapril was examined in normotensive and various hypertensive animal models. In 2-kidney, 1-clip renal hypertensive rats (2K-RHR), quinapril (0.1 to 1.0 mg/kg, p.o.) had a dose-related and sustained antihypertensive action, which was as potent as that of enalapril and approximately 40 times stronger than that of captopril. Heart rate was not changed by these doses of quinapril. In spontaneously hypertensive rats (SHR) and 1-kidney, 1-clip renal hypertensive rats, quinapril as well as enalapril dose-dependently produced a significant fall in blood pressure. The relative potency and duration of the effect of quinapril was the same as that of enalapril in these models. Quinapril at 30 mg/kg, p.o. lowered blood pressure and increased heart rate in normotensive rats. In contrast, quinapril and enalapril failed to reduce blood pressure in DOCA/salt hypertensive rats. In the repeated dose study, no development of tolerance was observed during the administration period in 2K RHR and SHR. The antihypertensive effects in 2K RHR was greater than those in SHR. Quinapril was more potent and long-lasting than enalapril in 2K RHR and SHR. From these results, quinapril is expected to be useful for the clinical treatment of hypertension.
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PMID:[Antihypertensive activity of the angiotensin converting enzyme inhibitor quinapril HCl: (S)-2-[(S)-N-[(S)-1-ethoxycarbonyl-3-phenylpropyl) alanyl]-1,2,3,4- tetrahydro-3-isoquinolinecarboxylic acid monohydrochloride in various hypertensive animal models]. 833 86

The aim of this study was to investigate the prognostic value of cardiopulmonary fitness in hypertension. From 1972 to 1982 oxygen uptake and heart rate were recorded during an exercise test to exhaustion in 216 patients (143 men). Their outcome was ascertained in 1994. During 3,411 patient years of follow-up, 53 patients suffered at least one fatal or nonfatal cardiovascular event and 25 patients died. After adjustment for age, gender, and weight, the relative hazard rates (RHR; Cox regression) of peak oxygen uptake (l.min-1) amounted to 0.44 (P = 0.01) for the first occurring cardiovascular events and 0.35 (P = 0.05) for all-cause mortality. These RHR remained significant after additional adjustment for traditional cardiovascular risk factors (RHR = 0.45 and 0.28, respectively; P < 0.05). Heart rate at 50 W did not predict outcome after adjustment for age and gender (P = 0.94 and 0.14, respectively), nor after additional adjustment for heart rate at rest (P = 0.86 and 0.61, respectively). In conclusion, a lower peak oxygen uptake, but not a higher submaximal heart rate, is significantly and independently associated with a higher incidence of cardiovascular events and a higher total mortality in hypertensive patients.
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PMID:Prognostic significance of peak oxygen uptake in hypertension. 883 31

The effects of the angiotensin II type 1 receptor antagonist YM358 on blood pressure were compared to those of the angiotensin converting enzyme inhibitor enalapril in one-kidney, one-clip renal hypertensive rats (1K1C RHR), two-kidney, one-clip renal hypertensive rats (2K1C RHR) and normotensive rats (NTR). Additionally, the local drug actions in peripheral tissues were investigated using isolated mesenteric arteries from these rats. In 2K1C RHR, YM358 and enalapril produced a long-lasting hypotensive effect in a dose-dependent manner. In 1K1C RHR, YM358 (30 mg/kg) also produced an antihypertensive effect, whereas enalapril (30 mg/kg) had no effect. Administration of YM358, but not enalapril, to 1K1C RHR, 2K1C RHR and NTR did not affect heart rate. In isolated mesenteric arteries from 1K1C RHR and 2K1C RHR, angiotensin II (Ang II), angiotensin I (Ang I) and tetradecapeptide (TDP), a physiologically active renin substrate, produced concentration-dependent vasoconstriction. YM358 (10(-7) M) inhibited the vasoconstricting responses to Ang II, Ang I and TDP in isolated mesenteric arteries. In contrast, enalaprilat (10(-7) M), an active metabolite of enalapril, did not completely inhibit the response to Ang I and TDP. These results indicate that YM358 has higher efficacy than enalapril for the treatment of hypertension.
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PMID:Effects of YM358, an angiotensin II type 1 (AT1) receptor antagonist, and enalapril on blood pressure and vasoconstriction in two renal hypertension models. 1070 80

The baroreflex control of heart rate (HR) was evaluated in conscious chronic renal hypertensive rats (RHR; 1K-1C, 2 mo) under control conditions and after reversal of hypertension by unclipping the renal artery or sodium nitroprusside infusion. Unclipping and nitroprusside infusion were both followed by significant decreases in the mean arterial pressure (unclipping: from 199 +/- 4 to 153 +/- 8 mmHg; nitroprusside infusion: from 197 +/- 9 to 166 +/- 6 mmHg) as well as slight and significant increases, respectively, in the baroreflex bradycardic response index (unclipping: from 0.2 +/- 0.04 to 0.6 +/- 0.1 beats x min(-1) x mmHg(-1); nitroprusside infusion: from 0.1 +/- 0.04 to 0.5 +/- 0.1 beats x min(-1) x mmHg(-1)). However, this index was still depressed compared with that for normotensive control rats (2.1 +/- 0.2 beats x min(-1) x mmHg(-1)). The index for the baroreflex tachycardic response was also depressed under control conditions and remained unchanged after hypertension reversal. RHR possessed markedly attenuated vagal tone as demonstrated by pharmacological blockade of parasympathetic and sympathetic control of HR with methylatropine and propranolol, respectively. A reduced bradycardic response was also observed in anesthetized RHR during electrical stimulation of the vagus nerve or methacholine chloride injection, indicating impairment of efferent vagal influence over the HR. Together, these data indicate that 2 h after hypertension reversal in RHR, the previously described normalization of baroreceptor gain occurs independent of the minimal or lack of recovery of baroreflex control over HR.
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PMID:Baroreflex depression persists in the early phase after hypertension reversal. 1135 63

The factors involved in maintenance and reversal of mean arterial blood pressure (MAP) in the chronic two-kidney one-clip hypertensive rat (2K1C-RHR) are still debated. The reduction in MAP after reversal of 2K1C hypertension has been ascribed either to release of a renal medullary depressor hormone (RMDH) or suppression of the renin-angiotensin and/or sympathetic nervous system. We studied in conscious rats: (i) The effects of angiotensin II receptor blockade (ARB; candesartan), sympathetic blockade (propranolol and phentolamine) or a combination on MAP in 6-week long 2K1C-RHR; (ii) The effects of reversal of 2K1C hypertension by removal of the constricting clip (unclipping, UC) or nephrectomy (Nx) on MAP, plasma renin activity (PRA) and noradrenaline (NA) spillover rates. The results show that: (i) MAP in the 2K1C-RHR was almost normalized by ARB but not significantly affected by the sympathetic blockade. The combination was not more effective than ARB alone; (ii) UC and Nx reduced MAP in 2K1C to similar levels as ARB. No significant changes in PRA or catecholamines could be detected in UC and Nx groups. We conclude that hypertension in 2K1C-RHR is maintained by the renin-angiotensin system without much contribution from the sympathetic nervous system. Furthermore, we found no evidence that UC of our model of 2K1C was associated with a generalized decrease in sympathetic tone or substantial release of RMDH from the unclipped kidney. Thus, we conclude that in the present model of 2K1C, both maintenance and reversal of hypertension are controlled by the renin-angiotensin system.
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PMID:Neurohormonal influences on maintenance and reversal of two-kidney one-clip renal hypertension. 1210 Mar 64

Tetrandrine (Tet) is an alkaloid isolated from the Chinese herb Radix of Stephaniae tetrandrae S Moore. Cardiac and vascular remodeling confers a very definite risk of increased cardiovascular morbidity and mortality. Remodeling reversal has been achieved in human and experimental animals treated with some antihypertensive drugs but not all. This review will focus on cardiovascular remodeling and therapeutic effects of Tet. Three models, SHR, RHR (high renin), and DOCA-Salt HR (low renin) were used. Left ventricular and vascular remodeling had been developed in rats with 8-week untreated hypertension. Tet was administrated by ig 50 mg/kg/d for 9 weeks. Tet lowered SBP, left ventricular weight to body weight ratio, vascular media thickness, media to lumen ratio, cardiac and vascular wet weight, and collagen content. Tet decreased markedly the density and total number of dihydropyridine binding sites and also decreased Ca2+ overload in myocardium and vessels. Tet improved haemodynamic changes during remodeling special diastolic function such as LV compliance and stiffness, increased cardiac myosin ATPase activity and Na+-K+, Ca2+ ATPase activity, and normalized vascular reactivity. Tet inhibited proliferation of vascular smooth muscle cells, induced and sensitized VSMCs to pro-apoptosis stimulation, improved the endothelial function, and increased NO production. These results suggest that Tet was not only an anti-hypertensive drug but also an excellent drug to reverse cardiac and vascular remodeling.
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PMID:Effects of tetrandrine on cardiac and vascular remodeling. 1246 44

The hypotensive effect of manascus was studied by using three well established rat models with hypertension: spontaneously hypertensive rat (SHR), renalvascular hypertensive rat (RHR, 2K1C) and DOCA-salt hypertensive rat. Manascus of 0.0, 0.4, 0.8, 1.2 g/kg BW (p.o.) were administrated daily to these animals for 3-4 weeks. Systolic blood pressure (SBP) and heart rate were measured once a week by using tail-cuff method. The hypotensive effect of manascus was observed in SHR and DOCA-salt hypertensive rats; and the effect was more potent in DOCA-salt hypertensive rat. Manascus showed less potential hypotensive effect in RHR.
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PMID:[Study on the hypotensive effect of manascus]. 1256 14


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