Figure 5.
Cocaine or high fat self-administration increases presynaptic oxA/hcrt-1 signaling. mEPSCs were recorded while VTA neurons were voltage-clamped at –70 mV before and 10 min after a 5 min bath application of oxA/hcrt-1 (100 nm). A–C, Example recordings of AMPAR mEPSCs before (i) and 15 min after (ii) oxA/hcrt-1 application in VTA slices of rats self-administering (A) regular food, (B) cocaine, or (C) high-fat chocolate food. Calibrations: 50 pA, 200 ms. D, AMPAR mEPSC amplitude (i) or frequency (ii) was not significantly different after oxA/hcrt-1 application to VTA neurons from regular food self-administering rats (n = 8, p > 0.05). E, F, In contrast, mEPSC frequency (ii), but not amplitude (i), was significantly increased after oxA/hcrt-1 application in (E) cocaine (n = 8, p < 0.05) or (F) high fat chocolate food self-administering rats (n = 6, p < 0.05). Each bar represents the mean and SEM. Paired t tests. D–F, Cumulative probability plots of amplitude (i) or interevent interval (ii) before (black) and after (colored) oxA/hcrt-1 application in example VTA neurons from (D) regular food, (E) cocaine, or (F) high fat chocolate food self-administering rats.