In vitro effect of angiotensin II on GABA release in rat hippocampus

In rat hippocampal slices [3H]GABA release evoked by 25 mM KCI consisted of Ca2+-dependent and Ca2+-independent fractions. Angiotensin II (AngII) at a concentration of 1 microM inhibited K+-stimulated [3H]GABA release. The effect of AngII (20% inhibition) on [3H]GABA release was decreased by the addition of 0.01 mM nipecotic acid to the superfusion medium. AngII also decreased the Ca2+-independent carrier-mediated [3H]GABA release (25% inhibition at a concentration of 1 microM). Different mechanisms of the neuromodulatory action of AngII on GABA release are discussed.