Fig. 3.

Conditional deletion of KCC2 in mature dentate granule cells results in a shift in E_GABA. Dentate granule cells were patched in acute coronal slices prepared from KCC2^FL mice injected with either AAV-Cre or AAV-GFP. A. Infected neurons were identified by GFP fluorescence and targeted for gramicidin perforated patch recordings (ML = molecular layer, GCL = granule cell layer, Hil = Hilus, Scale bar = 30 μm). B. Muscimol pulses were applied at different membrane holding potentials to determine E_GABA. AAV-Cre granule cells showed a positive shift in E_GABA compared to those infected with AAV-GFP. C. Muscimol (10 μM, 500 ms) pulses established the direction of GABA_AR signaling while holding the cell in I = 0. AAV-Cre granule cells showed a positive shift in the driving force of GABA_A mediated currents compared to AAV-GFP. D. Slices were treated with the KCC2 inhibitor VU0463271 (1 μM, 15 min) and the amplitude of muscimol currents was measured periodically every 20s at holding potential of −70 mV. Example traces from AAV-GFP and AAV-Cre dentate granule cells. E. The difference between between E_GABA measurements obtained before and after the VU0463271 was calculated. AAV-Cre granule cells displayed loss of E_GABA sensitivity to VU0463271 (*p < 0.05, **p < 0.005).