FIGURE 3.

Late Adolescence ketamine treatment induces pre- and postsynaptic changes in GABAergic transmission of the mPFC. (A) Schematic arrangement of electrophysiological recordings in layer II/III of the mPFC (upper). Samples traces of sIPSC (left) and mIPSC (right) from Veh and Ket slices (lower). (B) Quantitative analyses show that slices from Ket-treated animals have a significant decrease frequency of sIPSC compared to those from Veh rats (left) and increased amplitude of sIPSC (right) (t-test, ^∗p < 0.05, ^∗∗p < 0.01). (C) Frequency of mIPSC from Ket treatment was also reduced compared to the Veh group (left). Moreover, mIPSC amplitude showed the same direction of change as the sIPSC amplitude (right) (t-test, ^∗p < 0.05). (D) Sample traces of evoked IPSC amplitudes as a function of stimulus intensity plotted as input/output curves in inhibitory synapses (left). Compared to the Veh group, Ket treatment reduced the amplitude of eIPSC in approximately 20% of IPSC amplitudes at all stimulus intensities (right) (Repeated measures ANOVA/Bonferroni post hoc test, ^∗∗∗p < 0.001), sample values of statistical significance: stimulus intensity 0.2A, p < 0.01; 0.5A, p < 0.05; 0.9A, p < 0.05. (E) Paired-pulse responses superimposed after subtraction of the first pulse at 30, 70, 100, and 300 ms ISIs (left). Slices from Ket-treated rats showed an increase of paired pulse ratio at intervals equal or lower than 100 ms compared to the Veh group (Repeated measures ANOVA/Bonferroni post hoc test, ^∗∗∗p < 0.001). (F) Sample traces of synaptic responses evoked by a burst of 20 stimuli at 10 Hz (left). Depression induced by repetitive stimulation showed a reduction in its magnitude for slices from Ket rats compared to the Veh-treated group (right) (Repeated measures ANOVA/Bonferroni post hoc test, ^∗∗∗p < 0.001). Data are the mean ± SEM. Number of animals is indicated in parentheses or within bars. ^∗p > 0.05, ^∗∗p > 0.001, and ^∗∗∗p > 0.0001.