Participation of central cholinergic system in the effects of intracerebroventricular (i.c.v.) injection of angiotensin II (Ana II) on blood pressure and heart rate was studied in conscious, freely moving rats, Ang II dose-dependently increased blood pressure and decreased heart rate. Both atropine and mecamylamine (i.c.v.) pretreatments prevented the cardiovascular effects of Ana II. Pretreatment with a vasopressin V-1 antagonist also prevented the cardiovascular responses to Ang II. Our data suggest that the central pressor effect of Ang II is mediated in part by central acetylcholine via both muscarinic and nicotinic receptors, and vasopressin participates in this effect through V-1 receptors. (C) 2001 Elsevier Science Inc. All rights reserved.