A prolonged pressor response to intraventricular angiotensin II following bilateral nephrectomy

Intravenous injections of renin have been reported to produce a prolonged pressor response in nephrectomized rats which is mediated by angiotensin II (AII) and is shortened by anesthesia. Here we report a similar prolonged blood pressure increase for intraventricular AII but not for intravenous injections of AII. The extended pressor effects of central AII injections following nephrectomy are not due to water intake but may be partially accounted for by a prolonged action of antidiuretic hormone. The central effects of AII may explain the prolonged pressor action of intravenous renin injections in unanesthetized, nephrectomized rats, although an interaction with the sympathetic nervous system at two different sites of action is also possible. It is suggested that the anti-hypertensive action of the kidneys is through the release of a humoral agent, possibly prostaglandins.