Figure 8.

Regulation of GABA release elicited by 10 Hz stimulation. A, Agatoxin-pretreated slices. A comparison of control group data (Fig. 3A) with four slices (324 boutons) also treated with baclofen is shown. B, Baclofen does not increase the percentage of nondestaining boutons when 10 Hz stimulation is given. C, Baclofen shifts the distribution of individual destaining time constants toward longer values, although much less than for 2 Hz stimulation. D-F, Same as for A-C except on three conotoxin-pretreated slices (120 boutons). Stimulation is indicated by the black bar in A and D. G, The transient enhancement of f induced by 10 Hz stimulation is prevented by baclofen, although not by CP55940. Data are plotted for f values after 150 and 300 stimuli as in Figure 5A2. f increases in control conditions (control data calculated from data shown in Fig. 5A2, right plot; agatoxin present). H, Enhancement of f normalized to initial value for each condition.