THE MECHANISM OF THE RESERPINE-INDUCED ANTIDIURESIS IN THE RAT

Abstract

The delay of diuresis caused by reserpine in hydrated rats was not consistently prevented by prior administration of dibenamine or a potent anti-5-hydroxytryptamine substance (Methysergide), to the rats at the time of hydration. Carotid blood from rats under ethanol anaesthesia did not contain detectable antidiuretic activity. After administration of an intravenous dose of reserpine (50 μg/100 g) carotid blood collected at the time of maximum antidiuresis contained a detectable amount of antidiuretic activity which, in four experiments out of five, was destroyed by sodium thioglycollate. This, together with the finding that reserpine prolongs the time to the maximum rate of excretion of urine in hydrated rats, suggests that reserpine releases antidiuretic hormone from the neurohypophysis.