title: The role of angiotensin II in regulation of cerebrospinal fluid formation in rabbits.
abstract: The effect of central and peripheral administrations of angiotensin II (AII) on cerebrospinal fluid (CSF) formation was investigated in rabbits anesthetized with intravenous alpha-chloralose and urethane. CSF production was measured by the ventriculo-cisternal perfusion method with Blue dextran 2000 used as an indicator substance. AII infused intracerebroventricularly (i.c.v.) at rates of 5.5 and 55 pg min-1 significantly decreased CSF formation rate by 27% and 36%, respectively. This AII action could be completely blocked by simultaneously administered specific AII antagonist, [Sar1,Ala8]AII (saralasin), given i.c.v. at a rate of 5.5 ng min-1. Intracerebroventricular infusion of AII at a rate of 5.5 ng min-1 did not change CSF production. Saralasin, when given alone into the ventricular system (5.5 ng min-1), non-significantly increased CSF production by 12%. However, in 4 of the 6 animals studied, the rise in CSF production was statistically significant (by 23%). Intravenous infusion of AII at rates of 30 and 100 ng kg-1 min-1 was found not to change CSF formation rate. Also, i.c.v. administration of angiotensin I converting enzyme inhibitor, captopril (10 microliters min-1), did not influence CSF production. It is concluded that the centrally released AII can control CSF production. Our results suggest that under normal conditions, AII exerts a tonic inhibitory effect on CSF formation. In contrast, the blood-borne peptide seems not to influence this physiological process.
authors: Department of Clinical and Applied Physiology, Institute of Physiological Sciences, School of Medicine, Warsaw, Poland.
authors: A
authors: A
authors: Chodobski
authors: J
authors: J
authors: Szmydynger-Chodobska
authors: M B
authors: MB
authors: Segal
authors: I A
authors: IA
authors: McPherson
mesh_terms: D000804:Angiotensin II / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D002552:Cerebral Ventricles; D002555:Cerebrospinal Fluid / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D005260:Female; D007262:Infusions, Intravenous; D007263:Infusions, Parenteral; D008297:Male; D011817:Rabbits; D012504:Saralasin / Q000494:pharmacology
chemical_list: D002800:Cholinesterase Inhibitors; D000804:Angiotensin II; D012504:Saralasin