Figure 6. PSAM⁴-GlyR activation in D1-MSNs reduces GABAergic synaptic inhibition.

(A) Representative traces of GABA-A receptor-mediated synaptic currents in a PSAM⁴-GlyR⁺ neuron in aCSF, evoked during voltage steps from V_hold −88 mV (voltage steps: 1 s, −118 to −28 mV, 10 mV; electrical stimulation at 850 ms into voltage steps). Panel on the right shows the traces in expanded timescale corresponding to the gray rectangle on the left. (B) Representative traces of GABA-A receptor-mediated currents evoked in the same neuron from V_hold −28 mV (outward) and −118 mV (inward) in aCSF (gray) and uPSEM⁷⁹² (black). (C) Plot of the current–voltage relationship of the GABA-A receptor synaptic currents in aCSF and uPSEM⁷⁹² in neurons where the reversal potential of PSAM⁴-GlyR current shifted by >5 mV (n = 5, average shift of 17.0 mV). The reversal potential of GABA-A receptor-mediated current was −60.9 mV in aCSF and −51.6 mV in uPSEM⁷⁹². Inset (top left) shows values of GABA-A receptor synaptic currents in uPSEM⁷⁹² near the reversal potential in an expanded scale. (D) Plot of the current–voltage relationship of the GABA-A receptor-mediated synaptic current in aCSF and uPSEM⁷⁹² in neurons where the reversal potential of PSAM⁴-GlyR current did not shift (n = 3, average shift of 2.1 mV). The reversal potential of GABA-A receptor-mediated synaptic currents was similar in aCSF (−64.7 mV) and uPSEM⁷⁹² (−64.9 mV). Line and error bars represent means ± SEM, * indicates statistical significance.