Figure 1. Enhanced CP-AMPAR activity in BLA neurons that project to the NAcb after alcohol self-administration as compared to sucrose.

(A) Experimental timeline and schematic showing retrobead infusion in NAcbC followed by 40 days of ethanol (EtOH) or sucrose (Suc) self-administration. BLA recordings were conducted 24-h after the last self-administration session. (B – E) Parameters of EtOH (red bars) and sucrose (black bars) self-administration show behavior-matched performance between the sweetened alcohol and sucrose-only conditions with no differences in total responses (B), active lever responses (C), or reinforcers earned per hour (D), n=7/group. (E) Ethanol self-administration behavior resulted in average consumption of 0.83 g/kg per session. (F) Photomicrograph showing retrobead expression in the BLA following infusion in NAcbC. (G) Average plot showing a significant increase in sEPSC frequency in BLA neurons projecting to the NAcbC from alcohol exposed mice as compared to sucrose control; * - t(10) = 2.8, P = 0.02, alcohol n=6 cells from 6 mice, sucrose n=6 cells from 4 mice. (H) sEPSC amplitude was not changed by ethanol self-administration as compared to sucrose control. (I) Representative traces illustrating EtOH-induced increase in sEPSC frequency but not amplitude. (J) Time course of eEPSC amplitude (MEAN±SEM) during baseline (min 1 – 4) and bath application of NASPM (100 μM; min 5 – 20) from sucrose vs. ethanol self-administering mice. Data are normalized to minute 4 of the baseline. Alcohol n=6 cells from 6 mice, sucrose n=6 cells from 4 mice. (K) Peak inhibition of eEPSC amplitude by NASPM (MEAN±SEM from last 2 minutes of NASPM application) showing heightened sensitivity in EtOH self-administering as compared to sucrose control mice; * - t(9) = 2.5, P = 0.03. (L) MEAN±SEM paired-pulse ratio of eSPSC amplitude calculated during pre-NASPM baseline.