HYPOTENSIVE AND DIURETIC ACTIONS OF DILTIAZEM IN SPONTANEOUSLY HYPERTENSIVE AND WISTAR KYOTO RATS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 227  (2) , 472-477
Abstract
The hypotensive and diuretic effects of diltiazem and hydralazine were studied in conscious, spontaneously hypertensive rats (SHR) and their counterpart, Wistar Kyoto rats (WKY). Orally administered diltiazem induced dose-dependent hypotension both in SHR (10-60 mg/kg) and in WKY (30-100 mg/kg) and the effects were more pronounced in SHR than in WKY. Diltiazem did not cause tachycardia in either strain. Hypotensive doses of diltiazem acutely increases urinary Na+ excretion as well as urine volume in saline-loaded SHR and WKY. Chronic administration of diltiazem (30 mg/kg per day for 8 wk) to young SHR caused no changes in body fluid distribution or in plasma Na+ concentration. Hydralazine not only showed almost the same hypotensive potency in SHR and WKY but also resulted reflex tachycardia in both strains. Hydralazine (5 mg/kg) decreased urinary Na+ excretion in saline-loaded SHR. Evidently, diltiazem is an antihypertensive agent with an enhanced hypotensive action in the hypertensive state and without tachycardia and Na+ retention effects.