Central actions of angiotensin II on heart rate and blood pressure in mongrel dogs.

ABSTRACT

Angiotensin II is produced physiologically in response to renal ischaemia due to hypotension. It's effect on heart rate and blood pressure were studied on anaesthetised mongrel dogs. Angiotensin II was given in different concentrations, by intravenous, intraarterial in carotid artery and intracerebroventricular routes. Cervical vagotomy and carotid sinus inactivation were done is abolish the reflex inhibition produced by baroreflexes. Rise of B.P. is due to mainly peripheral vasopressor action of angiotensin II, however it is shown to have a central component as well. This is demonstrated by ICV injections. Tachycardia due to central action is also demonstrated in this study. Both actions are significant. This study also confirm the earlier findings that angiotensin II passes the blood brain barrier.