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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heart rate and blood pressure (BP) responses to a standardized 3 min isometric handgrip (IHG) test were measured in 32 normotensive men and compared with those found in 35 age-matched, drug-free men with established essential hypertension (BP range: 140--170/90--110). IHG testing in the normal subjects induced significant increases in heart rate (mean +/- SE: 7.6 +/- 3.3 beats/min), systolic blood pressure (19.4 +/- 5.3 mm Hg), and diastolic blood pressure (15.6 +/- 4.6 mm Hg). Although beginning from higher resting levels the hypertensive patients had similar degrees of increase in all three parameters. After chronic treatment with propranolol, the heart rate increase with IHG was suppressed in both study groups, but blood pressure responses differed, with a diminished pressor response to IHG seen in normal subjects and augmented pressor effects in the hypertensive group. Intravenous administration of phentolamine and propranolol completely abolished the pressor effects of IHG. These observations suggest that the autonomic control mechanisms mediating the responses to isometric exercise function similarly in drug-free normal and hypertensive patients and that the responses to IHG, mediated largely by endogenous catecholamine release, can be prevented by peripheral sympathetic receptor blockade.
J Cardiovasc Pharmacol
PMID:Effect of adrenergic receptor blockade on the responses to isometric handgrip: studies in normal and hypertensive subjects. 9 94

Renal hemodynamic effects of chronic prazosin therapy were studied in 10 men and with essential hypertension. Successful antihypertensive therapy was accompanied by diminution in total renovascular resistance, probably at the level of the afferent arteriole. The resistance change was unexplained by alterations in intravascular volume, the vasodilatory renal kallikrein-kinin system, or sympathetic nervous system activity, but was associated with a diminution in plasma renin activity. Potential mechanisms for the resistance decrement are discussed, including renal perfusion autoregulation, diminished activity of the vasoconstrictive renin-angiotensin system, and direct intrarenal afferent arteriolar alpha adrenergic blockade.
J Cardiovasc Pharmacol
PMID:Prazosin and renal hemodynamics: arteriolar vasodilation during therapy of essential hypertension in man. 9 96

The long-term hemodynamic effects of atenolol were studied in 10 patients with previously untreated essential hypertension in WHO stage I. Oxygen consumption, heart rate, cardiac output, and intra-arterial brachial pressure were recorded at rest in supine and sitting positions and during steady-state work at 50, 100, and 150 W. The patients were treated with 100 mg atenolol daily (200 mg in 1 patient) as the sole antihypertensive drug and were restudied after 1 and 5 years. After 1 year the blood pressure was reduced approximately 18% both at rest and during exercise, and the heart rate about 25%. The cardiac output was reduced 16% at rest supine, 27% at rest sitting, and about 20% during exercise. The calculated total peripheral resistance was not decreased compared to pretreatment values. After 5 years on treatment, the hemodynamic parameters were almost identical to those seen after 1 year. There was no increase in stroke volume or cardiac output and no decrease in the total peripheral resistance. Thus prolonged beta-blocker treatment over several years does not seem to normalize hemodynamics in patients with mild to moderate essential hypertension.
J Cardiovasc Pharmacol
PMID:Hemodynamic consequences of long-term beta-blocker therapy: a 5-year follow-up study of atenolol. 9 5

The value of prazosin and methyldopa administration was compared in 16 patients with essential hypertension during a 6 month randomized, double-blind, parallel trial. Both drugs were administered in combination with hydrochlorothiazide, 50 mg twice daily, until recumbent diastolic blood pressure was decreased to less than 90 mm Hg or the patient was receiving prazosin, 5 mg q.i.d., or methylodpa, 500 mg q.i.d. Addition of either prazosin or methyldopa to hydrochlorothiazide lowered blood pressure significantly and to a similar degree without altering plasma renin activity. Heart rate and weight were significantly increased during prazosin, but not methyldopa, therapy. Symptomatic side effects occurred with equal frequency during treatment with both agents and did not result in alteration or discontinuation of therapy in any patient. A decrease in frequency of administration from q.i.d. to b.i.d. or t.i.d./b.i.d. to q.d. did not adversely affect blood pressure control. Substitution of propranolol for prazosin or methyldopa provided similar antihypertensive effectiveness with a significant decrease in heart rate.
J Cardiovasc Pharmacol
PMID:Comparison of prazosin and methyldopa in essential hypertension: results of a randomized, double-blind, parallel trial. 9 37

To evaluate renal hemodynamic changes during therapy of essential hypertension, we treated 12 essential hypertensives in crossover fashion, with 1 month each of placebo, prazosin, and propranolol alone. During prazosin treatment, blood pressure was normalized with preservation of glomerular filtration rate, renal plasma flow, and renal blood flow. Propranolol, however, normalized blood pressure with an associated significant decline in glomerular filtration rate, renal plasma flow, and renal blood flow. The potential mechanisms are discussed.
J Cardiovasc Pharmacol
PMID:Renal perfusion changes during treatment of essential hypertension: prazosin versus propranolol. 9 38

The validity of noninvasive (iodine-131 iodohippurate renogram, iodine-131 ortho-iodohippurate clearance, indium-113m EDTA--technetium-99m DTPA sequential renal scan) and invasive (xenon-133 washout) radionuclide screening tests was evaluated in the diagnosis of 105 patients with unilateral renovascular hypertension (RVH) and in 45 patients with essential hypertension (EH). In RVH positive findings on the stenosed side were noted in 73% of renograms, 73% of o-iodohippurate-clearance tests (N = 22), 81% of sequential renal scans, and 90% of xenon-washout studies (N = 67). In a subgroup of 55 retrospectively selected patients with normal or improved blood pressure following renovascular surgery, the preoperative findings had been positive on the stenosed side in 78% of renograms, 75% of o-iodohippurate-clearance tests (n = 20), 85% of sequential renal scans, and 93% of xenon-washout studies (n = 23). The sequential renal scan appears to be a sufficiently reliable method in noninvasive screening for unilateral RVH, although invasive xenon-washout studies show a higher percentage of hemodynamic alterations in the stenosed kidney. o-iodohippurate clearance tests, and in particular xenon-washout studies, can reveal arteriosclerotic lesions in the contralateral, non-stenosed kidney, which may be of importance when the decision for renovascular surgery is pending.
Cardiovasc Radiol 1979 Apr 27
PMID:Predictive value of radionuclide methods in the diagnosis of unilateral renovascular hypertension. 43 31

The haemodynamic shifts during head up and head down tilt were investigated in adult spontaneously hypertensive rats (SHR) and matched normotensive control rats (NCR) under nembutal anaesthesia and autonomic blockage. During head up tilt a greater fall in blood pressure and stroke volume was observed in SHR than in NCR, while the reverse was true when tilted in the opposite direction. This altered cardiac response to venous filling, also observed in patients with essential hypertension, is suggested to be caused by an altered Frank-Starling relationship of the hypertrophied heart in hypertensive individuals.
Cardiovasc Res 1977 Nov
PMID:Haemodynamic changes during tilt after autonomic blockade in spontaneously hypertensive rats. 60 71

Sustained handgrip at 30% of the maximal strength and submaximal supine bicycle exercise elicited mean blood pressure increases of similar magnitude in healthy males and in men with essential hypertension WHO Stage 1 and 2, but with different contributions of systolic and diastolic blood pressure changes. While systolic blood pressure exceeded 22.7 kPa (170 mmHg) during static exercise in every hypertensive man, this did not occur in any of the control subjects. During dynamic exercise, the arterial blood pressure increase per litre increase in cardiac output was significantly less than during static exercise, indicating different patterns of circulatory adaptation to these two forms of stress. Combination of dynamic and static exercise tests might be of value for identifying subjects with a hypertensive pattern of circulatory regulation.
Cardiovasc Res 1978 May
PMID:Haemodynamic effects of static and dynamic exercise in males with arterial hypertension of varying severity. 67 26

Twenty-two patients with essential hypertension received a single dose of 2.5 mg cilazapril and were then randomised into a double-blind parallel group study to receive either placebo, 1.25 mg cilazapril + 0.5 mg cyclopenthiazide (CPTZ), 2.5 mg cilazapril + 0.5 mg CPTZ, or 2.5 mg cilazapril alone for 1 month. After oral administration of a single dose of 2.5 mg cilazapril, the active diacid cilazaprilat appeared rapidly in the plasma (Tmax 2.0 +/- 0.2 h). With the radioinhibitor assay used in this study, a single elimination phase of cilazaprilat was evident, with a half-life (t1/2) of 2-3 h. At steady state, the pharmacokinetics of cilazaprilat were similar to single-dose administration and were not altered by CPTZ. The Cmax and area under the curve (AUC) of cilazaprilat were directly proportional to dose. Cilazapril administration in the dose range of 1.25-2.5 mg produced a dose-proportional inhibition of angiotensin-converting enzyme (ACE) activity that was maximum 2 h after drug administration. The degree of ACE inhibition correlated with the plasma concentration-time profile of cilazaprilat and the maximum decrease in blood pressure (BP). The EC50 for ACE inhibition by cilazaprilat was 7.7 ng/ml after acute treatment and was not significantly altered during chronic administration or by concomitant administration of CPTZ. There was no evidence of a dose-related antihypertensive effect of cilazapril at steady state and, with the small numbers of subjects used in this study, there was no evidence of 24-h BP control with monotherapy.
J Cardiovasc Pharmacol 1992 Sep
PMID:Steady-state pharmacokinetics and pharmacodynamics of cilazapril in the presence and absence of cyclopenthiazide. 127 92

The acute renal, endocrine, and hemodynamic effects of the orally active endopeptidase inhibitor SCH 34826 (400 mg every 6 hours for five doses) were investigated in a group of 6 male patients [with established mild to moderate essential hypertension and left ventricular (LV) hypertrophy] in a balanced random-order double-blind, placebo-controlled cross-over study. Plasma atrial natriuretic factor (ANF) concentrations increased (p < 0.05) to fourfold control values after the first dose of inhibitor, but later postdose increments of ANF were less pronounced. Plasma cyclic GMP also increased significantly (p < 0.05). These effects were associated with a transient modest but significant (p < 0.05) increase in sodium excretion (50 mmol sodium in excess of placebo values) that was complete in 24 h. Mean 24-h urinary excretions of cyclic GMP and immunoreactive ANF were also significantly increased by 55 and 86%, respectively. Other urine indexes (including other electrolytes, volume, creatinine, aldosterone, and cortisol) and renal hemodynamics [including glomerular filtration rate (GFR) and effective renal plasma flow (RPF)] were unchanged. Renin-angiotensin-aldosterone system (RAAS) activity was not significantly altered. Plasma epinephrine increased after the initial three doses of SCH 34826. Systolic blood pressure (SBP) and heart rate (HR) were not altered by SCH 34826. Diastolic BP (DBP) increased slightly (p = 0.044). Acute inhibition of endopeptidase 24.11 by SCH 34826 in essential hypertension caused significant increments in plasma ANF and cyclic GMP together with modest natriuresis. No antihypertensive effect was observed in the first 30 h of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
J Cardiovasc Pharmacol 1992
PMID:Acute inhibition of endopeptidase 24.11 in essential hypertension: SCH 34826 enhances atrial natriuretic peptide and natriuresis without lowering blood pressure. 128 Jul 35


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