The circumventricular organs and the central actions of angiotensin.

This review discusses the central nervous system actions of the circulating hormone, angiotensin II. Access of this peptide likely is limited to those central structures which lack the blood-brain barrier. Three of the circumventricular organs, the area postrema, the subfornical organ, and the organum vasculosum, have all been suggested to be sites of action for angiotensin within the brain. The area postrema is a site of pressor action of angiotensin in many species but not in the rat. The subfornical organ is a site where angiotensin provokes drinking, a pressor effect, and the secretion of vasopressin. The organum vasculosum and adjacent tissue has also been suggested to be a site for these three central effects of the peptide. Blood-borne angiotensin probably does not act at the same locus as does angiotensin applied to the brain via its ventricular system.