Social isolation alters the effect of desipramine in the rat forced swimming test.

The present study determined whether rearing in social isolation alters the behavioural response produced by the selective noradrenaline uptake inhibitor, desipramine when rats are exposed to the forced swimming test or an open field arena. Male Wistar rats were raised from weaning either alone (isolation rearing) or in groups of five or six rats/cage (social rearing) for 4 weeks before behavioural testing. The results demonstrated that sub-chronic administration of desipramine (5, 10 and 20 mg/kg i.p.) 24, 5 and 1 h caused a dose-related decrease in immobility time and increase struggling and produced locomotor hypoactivity compared with saline treated rats in both isolation and socially reared rats. However, these effects were significantly greater in isolation than socially reared rats. The results indicate isolation rearing alters the response to aversive stimuli and that sub-chronic antidepressant treatment potentiates these effects.