Figure 3: Decreased surface GABA_AR expression and GABA-mediated inhibitory synaptic transmission in PX-RICS^−/− neurons.

(a) Sequential fluorescent (pHluorin) and differential interference contrast (DIC) images of PX-RICS^+/+ (left) and PX-RICS^−/− (right) live cortical neurons expressing γ2^EP. The settings of the microscope, lasers and detectors were kept unchanged during image acquisition. Scale bars, 10 μm. (b) Decreased surface expression of γ2 in PX-RICS^−/− neurons. Surface expression was calculated as follows: surface expression (%)=100 × (I_7.4−I_6.0)/(I_7.4N−I_6.0N), where I_7.4, I_6.0, I_7.4N and I_6.0N represent the fluorescent intensities in the imaging buffer at pH 7.4, pH 6.0, pH 7.4 containing NH₄Cl and pH 6.0 containing NH₄Cl, respectively. n=20 (PX-RICS^+/+) and 20 (PX-RICS^−/−) fields. (c) Representative traces of mIPSCs (left) and averaged traces of mIPSCs (right) in hippocampal CA1 pyramidal cells from PX-RICS^+/+ and PX-RICS^−/− mice. In total, 221 and 330 consecutive events with no overlap with other events were averaged for PX-RICS^+/+ and PX-RICS^−/− neurons, respectively. (d,e) The median intervals (d) and amplitudes (e) of mIPSCs in PX-RICS^+/+ and PX-RICS^−/− neurons. n=18 (PX-RICS^+/+) and 20 (PX-RICS^−/−) cells (c–e). Data are represented as means±s.e.m. NS, not significant; **P<0.01; ***P<0.001 (unpaired two-tailed Student’s t-test).