Poststimulation reduction of eIPSCs in MSO can be rescued by exogenous glutamine. Representative traces (A1) show a small increase in eIPSC size in the presence of 1.5 mm MSO when glutamine is coapplied. This result is contrasted with peak amplitude decrease in MSO alone illustrated in A2. Glutamine (5 mm) is ineffective in rescuing glutamine transport blockade by 5 mm MeAIB (B1, B2), confirming that in the MSO condition, exogenous glutamine is acting to replace the glutamine lost to reduced glutamine synthetase activity. Cont, Control; Pre-stim, prestimulation; Post-stim, poststimulation.