IMMOBILIZATION STRESS-INDUCED HYPERTENSION AND DOWN-REGULATION OF CENTRAL β-ADRENOCEPTORS IN RATS

Effects of chronic treatment with propranolol or atenolol on stress-induced changes in blood pressure and cerebral β-adrenoceptors were examined in rats. Immobilization stress (2 h daily for 2 weeks) induced a moderate elevation of blood pressure and downregulation of cerebral β-adrenoceptors. Chronic administration of propranolol (5 mg•kg-1) or atenolol (5 mg•kg-1) inhibited stress-induced hypertension. Propranolol and atenolol increased the density of cerebral β-adrenoceptors and inhibited the downregulation induced by stress. These results suggest that the antihypertensive action of propranolol and atenolol may be partly associated with the inhibition of stress-activated central β-adrenoceptor transmission.