Figure 3.

Decreases in instrumental responding for ethanol after GABA_AR α4 subunit knockdown in the NAc shell depend upon the concurrent experience of ethanol consumption. Two cohorts of rats were trained to lever press for ethanol and were then infused in the NAc shell with Ad-shα4 or Ad-NSS. On day 18 after viral infusion, rats underwent a single test session in which responding was (a–c) or was not (d–f) reinforced by ethanol delivery. (a) Active lever responses were decreased on day 18 when responding was reinforced (Ad-shα4 versus Ad-NSS groups, *P < 0.001). Panels b and c depict within-session responding during the 30-minute sessions by the same subjects depicted in panel a during the final session prior to virus infusion (b; baseline) and during day 18 (c). (b) There were no group differences during the baseline session. (c)There was a significant decrease in responding by Ad-shα4-treated rats on day 18 at the 5–10 and 10–15 minutes intervals (*P < 0.05, Ad-shα4 versus Ad-NSS groups) but not during the first 5 minutes of the session. (d) When responding was not reinforced on day 18, Ad-shα4-infused rats did not decrease active lever responses. (e) There were no group differences in the pattern of responding during the 30-minute baseline session. (f)There were no group differences in the pattern of responding during the 30-minute session on day 18 when responding was not reinforced. Data are presented as mean +/− SEM. n = 8 rats per group