Operant self-administration of ethanol in Warsaw high-preferring (WHP) and Warsaw low-preferring (WLP) lines of rats.

The results of the present experiment demonstrate that ethanol-preferring line of rats (WHP), and ethanol-nonpreferring line of rats (WLP) are able to acquire and maintain lever pressing reinforced by EtOH (oral operant EtOH self-administration) under FR-1 and FR-2 schedule of reinforcement. On the other hand, WHP rats but not WLP rats, displayed the high ability to acquire and maintain robust lever pressing for EtOH under FR-3 procedure. These data suggest that EtOH possesses stronger reinforcing properties in WHP rats. Nevertheless, WLP rats are able to acquire operant self-administration of EtOH when response demand of the reinforcement schedule is lower. Thus, both lines of rats can differ substantially in the amount of EtOH intake when its access is continuous and freely available, but less fundamentally when they respond for EtOH reward under low-demand schedules of partial reinforcement.