Release of γ-[3H]aminobutyric acid in rat brain cortical slices by α-scorpion toxin

Abstract In this paper, the effect of the α-scorpion toxin tityustoxin (TsTX) in the release of γ-[ 3 H]aminobutyric acid ([ 3 H]GABA) from rat brain cortical slices is described. The TsTX-stimulatory effect on the release of [ 3 H]GABA was dependent on incubation time and TsTX concentration, having an EC 50 of 0.33 μM. Tetrodotoxin (TTX) completely inhibited the TsTX action on [ 3 H]GABA release. The scorpion toxin effect was calcium-dependent and involves P/Q calcium channels. β-Alanine also induces the release of [ 3 H]GABA that was not inhibited by TTX but was additive in the presence of TsTX. The data suggest a neuronal origin for the release of [ 3 H]GABA by TsTX.