AT(1) RECEPTORS MEDIATE PRESSOR-RESPONSES INDUCED BY ANGIOTENSIN-II IN THE PERIAQUEDUCTAL GRAY AREA OF RATS

Microinjection of angiotensin II (ANGII) (0.01 to 1 nmol) into the per iaqueductal gray area (FAG) of anaesthetised rats caused dose-dependen t increases in blood pressure. Preinjection (10 min before) of losarta n (a selective non-peptide AT(1) receptor antagonist; 50 nmol) to the FAG reduced the presser response to ANGII whereas PD123319 (a selectiv e non-peptide AT(2) receptor antagonist; 50 nmol) did not affect the A NGII-induced hypertension. Thus, our data suggest that the activation of AT(1) but not AT(2) receptors mediates ANGII-induced blood pressure changes in the FAG area. (C) 1997 Elsevier Science Inc.