Figure 6.

The role of the GB_1a proximal C-terminal domain on baclofen-induced inhibition of Ca²⁺ transients. A, Baclofen did not affect spike-dependent presynaptic Ca²⁺ transients (ΔF/F) evoked by 0.2 Hz stimulation in 1a^−/− boutons and in GB_1a-Δ21-expressing boutons, but reduced it in GB_1a-WT-expressing boutons. Ca²⁺ transients were quantified as before (black) and after (gray) baclofen application (average of 10 traces). B, Average data on baclofen-induced modification in Ca²⁺ transients in 1a^−/− (n = 31, N = 6, p > 0.05), GB_1a-WT-expressing (n = 17, N = 4, ***p < 0.001, compared with 1a^−/−), and GB_1a-Δ21-expressing (n = 19, N = 5, p > 0.05, compared with 1a^−/−) boutons. One-way ANOVA with post hoc Bonferroni's multiple-comparison tests indicated significance. Error bars indicate SEM.