Reduction in oral ethanol self-administration in the rat by the 5-HT uptake blocker fluoxetine

Long-Evans rats (N = 4) maintained on ad lib food and water were initiated to self-administer ethanol using the sucrose-substitution procedure. Following initiation, the rats received IP injections of fluoxetine HCl in sterile water 30 minutes before selected daily self-administration sessions. On other sessions, the rats were injected with sterile water only. Doses of 1, 2, 3, and 5 mg/kg were tested in a random order. Only one drug dose was given each week and each dose was tested at least twice except the 5 mg/kg dose. As dose increased, responding for ethanol decreased with significant reductions at both the 3 and 5 mg/kg dose. The nature of the decrease was such that the duration of continuous responding at the beginning of the session was reduced respective to control and noninjection performance. Overall, the findings of this study support prior work with fluoxetine and other 5-HT blockers which appear to affect satiety mechanisms and possibly reinforcement efficacy.