Fig. 5. [³H]-GABA release from L7-pepE DCN synaptosomes is impaired in response to ionomycin, but it is more efficient after repetitive depolarization. (A) DCN synaptosomes from wild-type (black bars), Tg-1 (light grey bars) and Tg-2 (dark grey bars) were depolarized with 12, 15 or 35 mM KCl. Results are expressed as stimulus-evoked overflow, means ± s.e.m. of 5-10 independent experiments. (B) DCN synaptosomes from wild-type, Tg-1 and Tg-2 mice were treated as in A, except that [³H]-GABA release was induced by 0.5 µM ionomycin. Bars are means ± s.e.m. of 6-8 independent experiments. *P<0.05, Dunnett's multiple comparison test vs wild-type. (C) DCN synaptosomes from wild-type (), Tg-1 () and Tg-2 () mice were treated as in A and subjected to three sequential depolarizing pulses with either 15 mM (left panel) or 35 mM (right panel) KCl. [³H]-GABA release evoked by each pulse is expressed in percent of the release evoked by the first stimulus (means ± s.e.m. of four to five independent experiments). *P<0.05 and **P<0.001, one way ANOVA followed by Duncan's multiple comparison test.