Antihypertensive effects of betaxolol, a cardioselective .BETA.-adrenoceptor antagonist, in stroke-prone spontaneously hypertensive rats(SHRSP).

Effects of betaxolol, a cardioselective beta-adrenoceptor antagonist, on blood pressure and hypertensive complications in stroke-prone spontaneously hypertensive rats (SHRSP) were investigated. Betaxolol was provided in a dose of 33 +/- 1.8 mg/kg/day, orally in drinking water, throughout the experimental period. The chronic treatment with betaxolol inhibited the development of hypertension in SHRSP and reduced values of blood urea nitrogen, creatinine, total cholesterol, free cholesterol, triglyceride, phospholipid and HDL-cholesterol in serum. Treatment with betaxolol apparently inhibited the incidence of hypertensive lesions such as cardiac fibrosis, mesenteric vasculitis, proliferative and/or necrotic vasculitis and glomeruli showing collapse or vasculitis in the kidneys. To shorten the time before the onset of hypertension and the subsequent stroke, SHRSP were kept on a SP diet containing 0.39% Na instead of the F-2 diet. When the SHRSP were kept on the SP diet, all of the control SHRSP had cerebral apoplexy and severe hypertensive lesions in the heart and kidney. When betaxolol was chronically administered to SHRSP, cerebral apoplexy and hypertensive lesions in the heart and kidney were inhibited, but the effect on blood pressure was slight. Treatment with betaxolol reduced serum creatinine levels. Our observations show that betaxolol reduces blood pressure and potently inhibits hypertensive complications in SHRSP.