Influence of prazosin on cardiac reflex function.

Prazosin administration significantly decreased arterial blood pressure without affecting heart rate in pentobarbital-anesthetized dogs. Wile pressor and reflex bradycardic responses to angiotensin II were not altered by prazosin, reflex tachycardia produced produced by histamine and acetylcholine were significantly attenuated by prazosin. The failure of prazosin administration to cause an increase in heart rate may be due to the ability of the agent to inhibit reflex tachycardic responses to depressor stimuli, the mechanism of whcih needs to be further investigated.