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 (imipra mine and amitriptyline) or electroconvulsive shock (ECS) was investiga ted in the rat hippocampus. Long-term treatment with imipramine or ami triptyline significantly increased the density of GR, while chronic EC S significantly elevated the density of both GR and MR. Nifedipine adm inistered repeatedly had no effect on the basal GR and MR levels, howe ver when the rats were pretreated with nifedipine, the antidepressant drugs and ECS were unable to increase the density of CR, or GR and MR, respectively. These results indicate that, unlike in other models, ni fedipine blocks the effects of antidepressant drugs and ECS on GR and/ or MR. They also show, that antidepressant drugs and ECS differ in the ir effect on the density of GR and MR.