Figure 7. Loss of GINIP from either excitatory or inhibitory neurons affects inhibitory neuromodulation and increases seizure susceptibility.
(A) GINIP mRNA is expressed in excitatory and inhibitory cortical neurons. GINIP, vGlut1 and VGAT mRNAs were simultaneously detected in mouse cortical slices. All scale bars are 10 μm. n ≥ 3 experiments.
(B) Loss of GINIP reduces GIRK currents in response to baclofen. Representative traces of baclofen-induced holding current change in cortical pyramidal neurons from GINIP +/+ (black) or GINIP 1a/1a (red) slices are shown in the left and middle, whereas quantification of peak amplitude across multiple cells is shown on the right. Mean±S.E.M. (n=14 per group), **p<0.01, unpaired t-test. Baclofen = 50 μM.
(C) Loss of GINIP dampens baclofen-induced reduction of mIPSC frequency. Representative traces of mIPSC recorded from GINIP +/+ (black) and GINIP 1a/1a (red) cortical pyramidal neuron before and after baclofen are shown in the left and middle, whereas quantification of mIPSC frequency for different concentrations of baclofen relative to controls is shown on the right. Mean±S.E.M. n=13–16 per group. **p<0.01, ***p<0.001, ****p<0.0001, two-way ANOVA for GINIP genotype x baclofen concentration, with multiple comparisons at each concentration using Fisher’s LSD test.
(D, E) Loss of GINIP from Emx1+ (excitatory) neurons (B) or from VGAT+ (inhibitory) neurons (C) results in increased seizure susceptibility. 12–14 mice (male and female) per genotype. See Fig. S4 for results stratified by sex. Mean±S.E.M. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001, two-way ANOVA for genotype x concentration of bicuculline, with multiple comparisons at each concentration using Fisher’s LSD test.