To test the effects of NAc knockdown of the α4 GABAAR subunit on instrumental responding for ethanol, adenoviral vectors expressing shRNAs directed against the α4 GABAAR subunit (Ad-shα4-1) or the control adenoviral vector expressing an shRNA predicted to have no effect on mRNA expression (Ad-NSS) were infused into the NAc shell of rats trained to respond on a fixed-ratio 2 schedule for 0.1 ml aliquots of 20% ethanol. We showed previously that the Ad-shα4-1 virus down-regulates the mRNA and protein levels of the α4 subunit transiently, with significant reductions 18 days after infusion and recovery 25 days after infusion (Rewal et al. 2009). Ethanol intake from bottles available on the home cage was also transiently reduced after infusion of Ad-shα4-1 into the NAc shell for about 10 days beginning from ~day 12 (Rewal et al. 2009). Therefore, in the present study, we conducted daily test sessions from 5 to 30 days after virus infusion to encompass the time period during which we expected α4 knockdown.
