Vasopressin mediates the inhibitory effect of central angiotensin II on cerebrospinal fluid formation

Angiotensin II infused at low doses into the cerebral ventricles decreases cerebrospinal fluid (CSF) production. Since central angiotensin II also activates the sympathetic nervous system and promotes vasopressin release, the roles of these two factors in mediating the inhibitory effect of angiotensin II on CSF formation were studied. CSF production was measured in rats by the ventriculocisternal perfusion method. During central angiotensin II infusion (5 pg min(-1)), the following adrenoceptor antagonists were administered intravenously (i.v.): phentolamine (alpha(1)/alpha(2), 2 mg/kg per h), prazosin (alpha(1), 1 mg/kg per h), and propranolol (beta, 1 mg/kg per h). None of these agents affected the inhibitory effect of angiotensin II on CSF formation. In comparison, in animals administered i.v., the vasopressin V-1 receptor antagonist, d(CH2)(5)Tyr(Me)Arg-vasopressin (10 mu g/kg per h), the angiotensin II-induced decrease in CSF production was abolished. Our observations indicate, therefore, that vasopressin mediates the inhibitory effect of central angiotensin II on CSF formation. (C) 1998 Elsevier Science B.V.