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

We studied the effects of ouabain and verapamil on endothelin-1(ET-1)-induced contraction of the mesenteric artery in prehypertensive spontaneously hypertensive rats (SHRs) and age-matched Wistar-Kyoto (WKY) rats. Rings of mesenteric artery of SHRs and WKY rats aged 4 weeks were superfused with physiological saline solution and isometric tension was measured. ET-1 (10(-9) or 10(-8) M)-induced contractions were significantly larger in WKY rats than in SHRs. ET-1 (10(-7) M)-induced contractions were not significantly different between SHRs and WKY rats. Verapamil markedly inhibited ET-1 (10(-7) M)-induced contractions both in SHRs and in WKY rats. Although the percent inhibition tended to be larger in SHRs than in WKY rats, the difference was not significant. Ouabain significantly increased ET-1 (10(-7) M)-induced contraction in the presence of verapamil both in SHRs and in WKY rats. The increase was significantly greater in SHRs than in WKY rats. As a result, ET-1 (10(-7) M)-induced contractions were significantly greater in SHRs than in WKY rats in the presence of verapamil and ouabain. These results suggest that in ET-1-induced arterial contraction, [Na+]i-mediated [Ca2+]i regulation such as the Na+/Ca2+ exchange system might be greater in SHRs than in WKY rats, and that this might be, at least in part, involved in the pathogenesis or maintenance of hypertension in SHRs.
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PMID:Effects of ouabain and verapamil on endothelin-1-induced contraction of mesenteric artery in young spontaneously hypertensive rats. 172 23

The evaluation of mild to moderate hypertension must be carried out under the conditions in which treatments are usually prescribed, i.e., in general practice. After specific training of the physicians in the methods used, we evaluated the efficacy and safety of a new formulation of verapamil by comparing it with a reference drug: captopril. The main assessment criterion was the restoration of normal blood pressure in mildly to moderately hypertensive patients (blood pressure in excess of 160/95 mmHg). Blood pressure was evaluated by two methods: a mercury column sphygmomanometer, after the patient had rested in a half-sitting position for 10 minutes, and the ambulatory measurement of blood pressure (AMBP) using the SpaceLabs system. The results of this study involving 40 patients followed up for 3 months by 8 GPs in collaboration with our blood pressure unit were as follows: on verapamil, 47% of patients recovered normal values after 30 days of treatment and 71% after 60 days (with no change in dosage). On captopril, the normalization rates were 22 and 27% respectively. The highly significant reduction of blood pressure found by the "occasional" measurement for both treatments (p less than 0.001) was only faintly reflected by AMBP. Verapamil induced a reduction of nighttime blood pressure with no significant impact on heart rate. The clinical, paraclinical and electrocardiographic safety of both treatments was good.
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PMID:[Comparative efficacy of sustained release verapamil and captopril in mild to moderate arterial hypertension by ambulatory measurement and occasional measurement]. 177 3

Intravenous verapamil infusion reduced the arterial pressure (AP) in 13 out of 71 (76.5%) patients with severe arterial hypertension (AH) refractory to a two-week, three-step oral antihypertensive medication. Investigations including echo- and radio-cardiography were performed: in the control period before starting the three-step treatment; after two weeks before intravenous verapamil infusions; 10 days after stopping the verapamil administration, and before leaving the hospital during continued 3-4 weeks three-step therapy. The AP reduction was caused by decreased total peripheral resistance. Verapamil administration improved also intracardiac haemodynamics and left ventricular contraction. The AP was effectively controlled even after stopping the verapamil administration and continuing the three-step oral antihypertensive treatment. No manifest changes in the left ventricular function were registered.
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PMID:Efficacy of intravenous verapamil in arterial hypertension refractory to three-step antihypertensive therapy. 181 Jul

We have explored the effect of verapamil on renal hemodynamics and the renin-aldosterone system in ten patients with chronic renal disease and hypertension before and after 3 months of therapy. The mean +/- SEM glomerular filtration rates were 55 +/- 7 mL/min pre- and 55 +/- 8 mL/min posttherapy; the renal plasma flow was 231 +/- 29 mL/min pre and 244 +/- 35 mL/min posttherapy. The filtration fraction (0.24 pre; 0.23 post) and the renal vascular resistance (492 +/- 144 pre; 422 +/- 101 post) also remained stable with verapamil therapy. Blood pressure was lower after treatment (P less than .02) in 7 of 10 patients. Urinary albumin excretion was reduced only when blood pressure was lowered. Verapamil had a modest effect on the renin-aldosterone axis. While the mean increase in plasma renin activity from a pretreatment value of 1.8 +/- 0.42 ng/mL/h to 2.1 +/- 0.56 ng/mL/h failed to reach statistical significance, the increases in urinary aldosterone excretion from 8.2 +/- 2.2 mg/24 h to 11.1 +/- 2.3 mg/24 h did (P less than .001). Our results demonstrate that verapamil lowered blood pressure without renal hemodynamic compromise in hypertensive patients with chronic renal disease. The antihypertensive response was associated with a rise in urinary aldosterone excretion, with unchanged serum electrolytes. We conclude that verapamil is effective, safe, and well-tolerated in patients with renal impairment and hypertension, and may be suitable for clinical trials evaluating long-term progression of renal disease.
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PMID:Hemodynamic responses to verapamil monotherapy in patients with renal disease. 181 50

This double-blind, double-dummy, randomized clinical trial, conducted in elderly patients with mild hypertension, compared adherence to treatment, efficacy, side effects, and quality of life during treatment with transdermal clonidine versus oral sustained-release verapamil (verapamil-SR). Blood pressure declined significantly--from 148/95 mm Hg at baseline to 139/84 after titration and 135/86 after maintenance--with transdermal clonidine (n = 29), and from 156/96 to 144/85 and 148/88, respectively, with verapamil-SR (n = 29). Adverse event rates and quality-of-life questionnaire responses were similar in the two treatment groups. Transdermal clonidine was worn as directed during more than 96% of patient-weeks of treatment. Compliance with the oral verapamil regimen was less consistent: Verapamil-SR was taken as directed during approximately 50% of patient-weeks of therapy, and individual compliance, assessed by tablet counts, varied from 50-120%. In all, 86% of subjects were satisfied or highly satisfied with the convenience of transdermal therapy; 87% reported that side effects were slightly or not bothersome; 65% indicated that transdermal patches were more convenient than oral therapy; and almost 60% preferred transdermal to oral therapy. In this study transdermal clonidine and oral verapamil were equally safe and effective. A substantial majority of patients preferred transdermal to oral therapy, and adherence to treatment was greater with transdermal therapy.
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PMID:Therapeutic adherence in the elderly: transdermal clonidine compared to oral verapamil for hypertension. 186 25

Calcium channel blockers, originally developed for the treatment of angina and supraventricular arrhythmias, have been shown to lower elevated blood pressure effectively in hypertensive patients. Verapamil, nifedipine, and diltiazem represent prototype compounds for unique chemical classes with differing pharmacologic properties. These drugs lower elevated blood pressure with efficacy comparable with other commonly used antihypertensives. Combination therapy with other agents usually results in an additive response. Side effects are usually mild and reversible and usually are an extension of the drug's pharmacologic effects. Moreover, adverse metabolic effects on lipid, glucose, or potassium levels are not common. Because of the excellent antihypertensive effects of calcium channel blockers and their potential importance in a variety of other disease states, these agents should be routinely considered for use as a first-line antihypertensive agent in appropriately selected patients with hypertension of any severity as part of a comprehensive plan to minimize cardiovascular risk.
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PMID:The role of calcium channel blockers in the treatment of essential hypertension. 199 52

Cultured aortic smooth muscle cells from SHR proliferate more actively than cells normotensive control animals. This experimental data may be related to the hypertensive arteriopathy which mainly proceeds from media dystrophy made of hypertrophy, hyperplasia and excessive protein secretion of the smooth muscle cells. In order to precise the molecular cause of the phenomenon and the eventual action of calcium channel blockers on the development of this organic characteristic of hypertension, we have compared the responses of cultured cells from both SH and WKY rats to various agents in the absence or presence of verapamil. Cell proliferation, phospholipase C activation, and c-jun and c-fos oncogene expressions were measured in both cultures under the same conditions. The mitogenic actions of both foetal calf serum (FCS) and angiotensin II are two times more important on SH than on WKY rat cells. However, while inositol phosphate production elicited by angiotensin in also doubled in SHR cultures versus WKY ones. FCS-induced PLC activation is equivalent in both types of cells. The proto-oncogenes are more intensively expressed when WKY cells are stimulated by FCS than in the presence of angiotensin, but, contrarily to angiotensin, serum is not more active upon this parameter in SHR cultures. Verapamil (from 10(-8) M to 10(-5) M) decreases by 30% the proliferative effect of serum in both SH and WKY rat cells but is not significantly active on angiotensin stimulation. It also depresses in the same proportion the serum-induced inositol phosphate production and oncogene expressions without altering the responses to angiotensin. Nicardipine is less active than verapamil.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Role of external calcium on the growth of aortic smooth muscle cells in SHR]. 212 55

Left ventricular mass sometimes decreases during treatment of hypertension, but this response is inconsistent and its effects on left ventricular function are unknown. In a six-month randomized trial, we studied the ability of verapamil and atenolol to reduce left ventricular mass in 42 elderly patients with hypertension and the effects of this reduction in mass on cardiac function. The mean blood pressure (+/- SE) decreased in both the group that received verapamil (from 171.4 +/- 3.2/93.0 +/- 2.5 mm Hg to 142.9 +/- 2.8/79.0 +/- 2.0 mm Hg) and the group that received atenolol (from 179.6 +/- 4.6/98.5 +/- 2.4 mm Hg to 148.1 +/- 3.3/83.4 +/- 1.2 mm Hg), but the atenolol-treated patients more frequently required the addition of chlorthalidone to achieve blood-pressure reduction (P less than 0.01). Verapamil resulted in a reduction in the left-ventricular-mass index from 104 +/- 5 g per square meter of body-surface area to 85 +/- 5 g per square meter (P less than 0.01). Atenolol did not produce a reduction in the left-ventricular-mass index (109 +/- 9 g per square meter before treatment vs. 112 +/- 10 g per square meter after treatment). Two weeks after the withdrawal of antihypertensive therapy, blood pressure returned to pretreatment values. Nevertheless, in patients whose left ventricular mass had decreased, two measures of diastolic filling, the peak diastolic filling rate to the peak ejection rate, were significantly higher than before treatment (2.42 +/- 0.2 vs. 3.31 +/- 0.4 [P less than 0.05] and 0.61 +/- 0.03 to 0.85 +/- 0.05 [P less than 0.05], respectively). Diastolic filling was unchanged in the group that had no reduction in left ventricular mass. Cardiac output and the ejection fraction at rest and during mild exercise were unchanged in both groups as compared with baseline values. We conclude that left ventricular mass can be reduced in elderly patients with hypertension and mild ventricular hypertrophy who receive antihypertensive therapy. Reduction occurs more frequently with verapamil than with atenolol therapy, increases diastolic filling, and does not impair systolic function.
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PMID:The effects of antihypertensive therapy on left ventricular mass in elderly patients. 213 76

Studies were carried out to examine the relationship between blood pressure lowering using the Ca2+ channel blocker verapamil, and regression of ventricular hypertrophy, in the spontaneously hypertensive rat (SHR). Untreated male SHR showed rapidly developing hypertension (systolic pressure 194 +/- 2 mm Hg, 109 days of age) and moderate ventricular hypertrophy. Verapamil (Calan-SR, G.D. Searle Co.) treatment for 30 days at maximum doses of 18.7 and 49.9 mg/kg per day supplied in the food, lowered blood pressure maximally 37 mm Hg. The drug had no effect on heart rate. Decrease in the mass of the left ventricle plus interventricular septum was positively correlated with the verapamil-induced decrease in blood pressure (r = 0.69, P less than 0.001). SHR exposed continuously to 500 ppm carbon monoxide (CO) for 30 days showed a similar decrease in blood pressure (33.0 mm Hg). Such SHR, however, displayed increases in mass of the left ventricle plus septum and right ventricle, and of hematocrit, nearly identical to same age Sprague-Dawley rats similarly exposed to CO. Neither verapamil nor CO treatment altered myocardial water content. The results suggest that a modest lowering of blood pressure with verapamil in the SHR produces a relatively rapid decrease in left ventricular mass. It also shows that even when afterload is reduced in the SHR, as with CO, substantial ventricular hypertrophy develops, probably because of augmented preload, and that it is comparable to that produced in non-hypertensive rats.
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PMID:Effects of verapamil and carbon monoxide on blood pressure and heart mass in the spontaneously hypertensive rat. 214 23

In this work, we investigated the effects of pre-columns and press-fit connectors on automated cold on-column injection capillary gas chromatography. Verapamil, a calcium channel blocking vasodilator used in the treatment of angina, arrhythmias and hypertension, and norverapamil, an active metabolite, were used as model compounds in these investigations. Wide-bore fused-silica tubing deactivated with OV-1701-vinyl was also studied with respect to its suitability as pre-column material. The detector response of verapamil versus an internal standard was consistent at micrograms/ml and ng/ml levels, while that of norverapamil decreased with the amount injected. However, the decrease in response of norverapamil appeared to be unrelated to the presence of a pre-column or press-fit connector in the chromatographic system.
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PMID:Effects of the pre-column in automated on-column injection capillary gas chromatography. 225 87


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