Role of angiotensin II in rat cerebellum

Abstract

Angiotensin II (All) 1 the octapeptide which has found present within the central nervous system, was demonstrated for its action on Purkinje cells (P cells) as well as interaction with gamma-aminobutyric acid (GAEA ) and its antagonists. It was suggested that All may act on Purkinje cells via GABA mechanism. To elucidate possible modulatory action of this peptide, two methods have been employed in this study. First, by means of micro-iontophoretic techniques, All and GABA depressed Purkinje cell discharge and these depressant effects were enhanced by AOAA, the inhibitor of GABA - keto - glutaric transaminase (GABA - T). AOAA induced enhancement of All was antagonized by saralasin, All - antagonist, without any effects on action of GABA, while previous evidence demonstrated that the actions of ATI on p cell was also blocked by bicuculline. To elucidate possible effects of All on the release of endogenous GABA, the second, collection methods using high performance liquid chromatography (HPLC) were performed for quantitative assay of amino acids. It is suggested that modulatory action of All may be due to potentiation of endogenous release of GABA in the rat cerebellum.