Repeated imipramine treatment increases the responsivity of the rat hippocampus to dopamine. An in vitro study.

The sensitivity of hippocampal neurons to dopamine was studied in hippocampal slices obtained from rats treated acutely (10 mg/kg) or repeatedly (10 mg/kg, 14 days, twice a day) with imipramine. In non-treated rats dopamine induced a slight excitation or depression of the firing rate of CA 1 pyramidal neurons in slice preparations. Hippocampal slices prepared from the imipramine-treated rats displayed greater changes in the firing rate after dopamine application. Repeated imipramine administration also increased the number of slices sensitive to dopamine. it is concluded that repeated imipramine administration induces supersensitivity of hippocampal dopamine receptors.