Angiotensin receptors at the spinal cardiovascular loci

Intrathecal injection of graded doses of angiotensin elicited a significant, dose-related rise in blood pressure without affecting heart rate. Tachyphylaxis appeared with repeated intrathecal injections but intravenous angiotensin could elicit pressor effects at this stage. Intrathecal administration of saralasin per se, did not affect resting heart rate or blood pressure. However, pretreatment with saralasin completely antagonized the intrathecal angiotensin-induced rise in blood pressure without significantly altering the effect of intravenous angiotensin. A facilitatory role for blood pressure regulation is suggested for the angiotensin receptors at the spinal cardiovascular loci.