Effects of chronic treatment with carvedilol on smooth muscle tone and endothelium-dependent relaxation of aorta in stroke-prone spontaneously hypertensive rats.

ABSTRACT

Effects of chronic treatment of stroke-prone spontaneously hypertensive rats (SHRSP) with carvedilol, an agent which has both alpha and beta-adrenoceptor blocking actions, on spontaneous muscle tone and on structural and functional abnormalities of endothelium were studied. The treatment of SHRSP with the drug of the dose of 30 to 200 mg/kg/day lowered the blood pressure significantly. Spontaneous muscle tone in endothelium-removed preparation disappeared by the treatment. Noradrenaline-induced contraction was depressed by the treatment in endothelium intact preparation but not in endothelium removed preparation. The treatment prevented the structural and functional abnormalities of endothelium. Similar results were obtained by the treatment with propranolol. These results indicate that carvedilol prevented abnormal contraction of SHRSP aorta through protective effects on smooth muscle and endothelium. These effects may play roles in blood pressure lowering effect of carvedilol.