Effects of bevantolol HCl on immobilization stress-induced hypertension and central β-adrenoceptors in rats

Abstract

Effects of chronic treatment with bevantolol, a β-adrenoceptor blocker, and of repeated immobilization stress on blood pressure, body weight, and [ 3H]dihydroalprenolol ([ 3H]DHA) binding to the cerebral cortex were examined in rats. Systolic blood pressure increased to approximately 150 mmHg when stress was applied for 14 days (2 h day −1). This increase was inhibited by chronic treatment with bevantolol (250 mg kg −1 daily). However, bevantolol did not suppress the inhibition of body weight gain by stress. The maximum number of [ 3H]DHA binding sites ( B max) in the cerebral cortex was decreased by stress without changing the affinity, and the decrease in B max mainly reflected the reduction of β 1-adrenoceptors. Bevantolol treatment (250 mg kg −1 increased the B max to 137% and completely inhibited the downregulation of β-adrenoceptors by stress. These results show that bevantolol can inhibit both the hypertension and downregulation of the central β 1-adrenoceptors induced by stress.