Figure 3.

Gad1 deletion lowers vesicular filling of GABA. a, Application of the low-affinity, competitive GABA_A antagonist TPMPA reduced the amplitude of mIPSCs in WT (left) and Gad1^−/− (right) cultures. Washout of the drug allowed partial recovery of amplitudes. b, Cumulative distribution of mIPSC amplitude in WT (left) and Gad1^−/− (right) cultures. TPMPA (red line) induced a larger left shift in the distribution of mIPSC amplitude in Gad1^−/− cultures compared to WT, suggesting lower vesicular content of GABA in cultures lacking GAD67. c, A plot of the degree of TPMPA block (as a percentage of baseline control) versus mIPSC amplitude revealed that mIPSCs are more sensitive to TPMPA in Gad1^−/− for a large range of sizes. WT, n = 6 cells; Gad1^−/−, n = 5 cells; ***p < 0.001. Ctrl, Control.