The effect of repeated combined treatment with nifedipine and antidepressant drugs or electroconvulsive shock on the hippocampal corticosteroid receptors in rats.

The effect of nifedipine, a calcium channel antagonist, on changes in the density of glucocorticoid (GR) and/or mineralocorticoid receptors (MR), induced by long-term treatment with antidepressant drugs (imipramine and amitriptyline) or electroconvulsive shock (ECS) was investigated in the rat hippocampus. Long-term treatment with imipramine or amitriptyline significantly increased the density of GR, while chronic ECS significantly elevated the density of both GR and MR. Nifedipine administered repeatedly had no effect on the basal GR and MR levels, however when the rats were pretreated with nifedipine, the antidepressant drugs and ECS were unable to increase the density of GR, or GR and MR, respectively. These results indicate that, unlike in other models, nifedipine blocks the effects of antidepressant drugs and ECS on GR and/or MR. They also show, that antidepressant drugs and ECS differ in their effect on the density of GR and MR.