EFFECTS OF ARGIPRESSIN INJECTED INTO MEDIAL AMYGDALOID BODY ON BLOOD-PRESSURE AND HEART-RATE IN RATS

Graded injections of argipressin (Arg, 150, 300, and 600 ng / 1.5 mul CSF, 2 min) into the medial amygdaloid body in anesthetized rats produced a dose-related increase in the mean arterial pressure and heart rate (Maximal DELTAMAP=2.9 +/- 1.5 kPa, Maximal DELTAHR=67 +/- 38 bpm), which lasting > 40 min at 600 ng dosage. Naloxone (15 ug/ 15 mul CSF) injected into the lateral ventricle blocked the cardiovascular responses to Arg. These results suggest that Arg exerts a central action on the cardiovascular system via the opioid in the lateral ventricle.