1. Infusion of angiotensin into both vertebral arteries or into a lateral cerebral ventricle of dogs anaesthetized with morphine-chloralose elicited a centrally mediated rise in blood pressure.
2. Heat coagulation of the area postrema and immediately adjacent structures abolished the pressor response to infusion of angiotensin into the circulation of the vertebral arteries, but did not alter the pressor response when the peptide was delivered into a cerebral lateral ventricle; transection of the midbrain eliminated the latter response but not the former.
3. It is concluded that there are at least two areas in the dog's brain that respond to angiotensin by inducing a raised blood pressure.