SELECTIVE SEROTONIN REUPTAKE INHIBITORS DECREASE SCHEDULE-INDUCED-POLYDIPSIA IN RATS - A POTENTIAL MODEL FOR OBSESSIVE-COMPULSIVE DISORDER

Schedule-induced polydipsia was used to determine the effects of selec tive serotonin re-uptake inhibitors on adjunctive water consumption. P olydipsia was induced in food deprived rats by exposure to a fixed tim e feeding schedule (FT = 60 s) for 150 min per day for 22 days. Select ed polydipsic rats consumed 3-4 times greater volume of water compared to food deprived control rats. Chronic administration of the selectiv e serotonin re-uptake inhibitors fluoxetine and clomipramine (CMI) at 5 mg/kg per day and fluvoxamine at 10 mg/kg twice a day significantly decreased schedule-induced polydipsia (SIP) on day 15 and throughout t he remainder of the study compared to control rats. The noradrenergic re-uptake inhibitor, desipramine (DMI), only decreased SIP behavior on day 1. The neuroleptic, haloperidol (0.03 and 0.1 mg/kg), and the ben zodiazepine, diazepam (2.5 mg/kg), failed to alter SIP behavior. Since obsessive-compulsive disorder (OCD) and polydipsic behavior both invo lve excessive expression of a normal behavior, the polydipsia model ma y be relevant for the prediction of compounds useful in the treatment of OCD.