Effects of β-adrenoceptor agonists and antagonists in rat kidneys

Abstract

The present experiments were designed to study renal effects of β-adrenoceptor agonists and antagonists with reference to β1-and β2-adrenoceptors. Wistar rats, anesthetized with urethan, were continuously hydrated with saline solution. The β-blockers used were atenolol as a selective βi-antagonist, butoxamine as a selective β2-antagonist and propranolol as a non-selective β-antagonist. The β-stimulants used were isoproterenol as a non-selective β-agonist and salbutamol as a selective β2-agonist. The different types of β-antagonists such as atenolol, butoxamine and propranolol all produced dose-related increases in urine volume and urinary sodium excretion without changing urinary potassium excretion. Isoproterenol and salbutamol decreased urine volume and urinary sodium excretion. The diuretic effects of atenolol, butoxamine and propranolol were abolished by simultaneous infusion of either isoproterenol or salbutamol without inducing any change in renal blood flow. The results obtained suggest the fact that the diuretic effects of atenolol, butoxamine and propranolol are closely related to activity of β-adrenoceptors in rat kidneys, although there is no selectivity to either β1-and β2-adrenoceptors so far as diuresis is concerned.