EFFECTS OF CHRONIC IMIPRAMINE ON EXPLORATION, LOCOMOTION, AND FOOD WATER INTAKE IN RATS/

Three groups of rats were subjected to 15 daily injections of imiprami ne (10 or 20 mg/kg) or vehicle control injections, respectively. Durin g the treatment period, both imipramine groups failed to grow while th e control group gained weight normally. Both dosages of imipramine sup pressed food intake significantly, while water intake was only reduced by 20 mg/kg of imipramine and only during the first 5 days of treatme nt. Twenty-four hours after the last imipramine injection, the animals were subjected to a test battery designed to demonstrate potential ch anges in locomotion and/or exploration. While locomotion appeared unaf fected by both dosages of imipramine, the group receiving 20 mg/kg of imipramine demonstrated a significantly reduced exploration. The explo ration of the group receiving imipramine in the concentration of 10 mg /kg was only marginally changed. The temporal pattern of exploration o f the animals receiving 20 mg/kg of imipramine revealed that chronic i mipramine treatment was associated with an initial ''hyperexploration' ' followed by an ''overhabituation,'' resulting in an overall reductio n of exploration during a 15-min period.