time (F(5,110) = 2.6, P < 0.05; Fig. 2c). These effects were accounted for by a significant decrease in active lever responding by the Ad-shα4 group 5–10 minutes (P < 0.01) and 10–15 minutes (P < 0.05) after session onset, as compared to responding by Ad-NSS rats. Hence responding was the same for both groups for the first 5 minutes, and as the session progressed, rats with GABAAR α4 subunit knockdown responded less compared to control rats. These findings suggest that responding for ethanol in rats infused with the Ad-shα4 decreases after the rats have the opportunity to experience responding reinforced by ethanol delivery.
