Figure 7.

meIPSCs are sensitive to disruption of the glutamate-glutamine cycle by MeAIB. A₁, Consistent with an increase in eIPSC size caused by an increase in probability of release, meIPSCs under control conditions showed no change in potency and a reduction in failures after the burst stimulation protocol. This is illustrated by the lack of change comparing the events evoked preceding the moderate stimulation (Pre-stim; left) to events after the stimulation (Post-stim; right), and by a decrease in the number of failures post-stim (right). The inset (potency) depicts the average potency (event size excluding failures) before (thin line; mean of 91 events) and after (thick line; 102 event) stimulation. A₂ plots the event area versus stimulus time for the cell depicted in A₁. Note that events are all-or-none and that there is no change in event area for successes after stimulation but a decrease in failures (evident as a decrease in 0 pC events). A₃, Plot of change in potency and success rate of individual cells (n = 4) before and after the burst stimulation protocol. Average effect is plotted by the thick line, ± SEM. Note that there is no change in potency but a significant increase in success rate (decreased failures; p < 0.03) after stimulation. B₁, Consistent with a decrease in eIPSC size because of a decrease in GABA release, meIPSCs under 5 mm MeAIB-exposed conditions exhibited a decrease in potency (mean of 128 events pre-stim and 149 events post-stim) and an increased probability of release after the burst stimulation protocol. This is illustrated by the reductions evident comparing the events evoked preceding the moderate stimulation (Pre-stim; left) to events after the stimulation (Post-stim; right), and by a decrease in the number of failures post-stim (right). The inset (potency) depicts the average potency (event size excluding failures) before (thin line) and after (thick line) stimulation protocol. B₂ plots the event area versus stimulus time for the cell depicted in B₁. Note that events are all-or-none and that there is a reduction in event area for successes after stimulation and a decrease in failures (evident as a decrease in 0 pC events). B₃, Plot of change in potency and success rate of individual cells (n = 4) before and after the burst stimulation protocol. Average effect is plotted by the thick line, ± SEM. Note that there is a significant decrease in potency ( p < 0.03) and a significant increase in success rate (decreased failures; p < 0.04) after stimulation.