Figure 8. Minimally-evoked natural stimulus pattern reveals glutamine-dependent reduction in evoked synaptic EPSCs.

EPSC amplitudes were analyzed from intracellular recordings of CA1 cells in which the Schaffer collaterals were minimally-stimulated with natural patterns in the absence or presence of glutamine. (a) Representative example of averaged minimally-evoked EPSC amplitudes (upper panel) during 0.2 Hz stimulation from a CA1 cell over 5 min during baseline (left), the first 5 min post-nLFS (middle) and 10–15 minutes post nLFS (right). Red dotted line represents mean baseline amplitude. Relative amplitudes of evoked EPSCs from 13 individual cells (middle panel) during baseline, the first 5 min post-nLFS (Post-Stim) and 10–15 minutes post nLFS (recovery). Red continuous line depicts representative median response corresponding to the representative traces. Time course of evoked EPSC amplitudes from a representative cell normalized to the median of the baseline (bottom panel). Blue bar represents duration of natural stimulus. (b–d) same as above but with (b) nLFS in glutamine (n=11), (c) nHFS in aCSF (n=13) and (d) nHFS in glutamine (n=11). A significant reduction of evoked EPSCs was seen with nHFS in aCSF during post-stim (0.65 median, **p<0.05) and recovery (0.58 median, **p<0.05), but not in glutamine (One way ANOVA; aCSF p=0.0134, glutamine p=0.9125 for difference within groups). There was no significant difference in evoked EPSCs with nLFS with or without glutamine.