Avoidance learning during antidepressant withdrawal in mice.

ABSTRACT

Shuttle-box avoidance acquisition, locomotor activity and density of adrenoreceptors in the cerebral cortex have been evaluated, in CD-1 mice, during withdrawal from repeated treatment with desipramine or mianserin (5 or 14 daily injections of antidepressant drug, 10 mg kg-1). Withdrawal from mianserin did not produce any behavioural or neurochemical change. Mice withdrawn from desipramine exhibited avoidance facilitation, when training started 24 h (but not 72 or 120 h) after the last injection. Locomotor activity was not affected and no change was found in the density of beta-adrenoreceptors. An up-regulation of alpha 2- and, to a lesser extent, of alpha 1-adrenoreceptors, occurred 72 h following desipramine withdrawal. However, the assessment of the role played by these neurochemical changes in the avoidance facilitation observed during withdrawal from the antidepressant treatment requires further study.