Figure 8.

Neurotransmission in cultured cortical neurons. A1, A2, GABA (A1) and glutamate (A2) basal and evoked release. Columns 1, 3, and 5 represent basal release (5 mm KCl). Evoked release with 56 mm KCl was performed during the 3 min corresponding to columns 2 and 4. Each column represents amino acid concentration released/minute, pooled by three fractions, with triplicate determinations per animal. ∗p < 0.05; ∗∗p < 0.01. B1, B2, Decay of EPSCs during electrical stimulation. Field stimulation was delivered at 10 Hz for 20 s (200 stimuli) and EPSCs recorded in whole-cell mode. The intracellular solution contained QX314 to prevent spiking. Graphs show the decline of EPSC amplitude during 10 Hz stimulation in wild-type (B1, top) and GLS1−/− (B1, bottom) cells. EPSC traces are shown for closed circles. The decay followed a single exponential (τ = time constant). The decay time constant was significantly shorter in GLS1−/− neurons (B2). Neither the average amplitude of the first three EPSCs nor the average amplitude of the last 30 EPSCs showed significant genotypic variation (data not shown). Numbers of recorded cells are indicated in parentheses. Data were obtained from three sets of matched cultures. ∗p < 0.01. Error bars represent SEM.