Shifts in discriminative control with increasing periods of recovery in the rat.

BACKGROUND: During recovery from alcoholism, other behavior likely increases. The development of alternative behavior may reduce attention to alcohol-associated stimuli. This could result in greater persistence of the alternative behavior when individuals again encounter alcohol-associated stimuli that might precipitate relapse. Developing animal models of this process could facilitate a better understanding of the mechanisms involved in relapse and recovery. However, current preclinical models of recovery and relapse rarely measure alternative behavior. Thus, our objective was to establish a procedure in rats in which an increase in alternative behavior (responding for food) reduced responding for ethanol (EtOH). The amount of responding for food and EtOH was then assessed after re-exposure to the alcohol-associated stimulus after varying the number of preceding sessions of increased responding for food and reduced responding for EtOH. These results were compared with those from a parallel group responding for saccharin solution instead of EtOH.
METHODS: The solution (EtOH or saccharin) was always available following 5 responses. Presentation of flashing stimulus lights indicated food delivery followed 150 responses and resulted in responding predominately for the solution (84 to 86% of total responses). Presentation of solid stimulus lights indicated food delivery followed 5 responses and resulted in responding predominately for food (1 to 3% of total responses were for the solution). Rats were exposed to solid light conditions for 0, 1, 2, 4, or 16 consecutive sessions before being re-exposed to the flashing stimulus lights in extinction.
RESULTS: Responding for either solution resumed when rats were re-exposed to the flashing stimulus lights (associated with solution-predominate responding). However, more responses occurred on the food lever with longer recent histories of responding for food instead of the solution.
CONCLUSIONS: These results suggest that the longer alternative behavior replaces drinking, the more that attention to stimuli associated with drinking decreases. These results are consistent with the notion that the risk of relapse declines with longer periods of recovery because alternative behavior comes to predominate even in the presence of stimuli associated with drinking.