Effect of repeated treatment with antidepressant drugs and electroconvulsive shock (ECS) on [3H] prazosin binding to different rat brain structures.

The influence of acute and repeated treatment with imipramine, amitriptyline, mianserin, citalopram and ECS on alpha 1-adrenoceptors in different structures of the rat brain (cerebral cortex, hippocampus and thalamus) was measured using [3H] prazosin as a ligand. Repeated, but not acute, treatment with all the above antidepressant drugs and ECS induced an increase in the density of alpha 1-adrenoceptors in the cerebral cortex. On the other hand, no changes were found in the hippocampus and thalamus, with an exception of the increased number of [3H] prazosin binding sites in the thalamus after imipramine. The results suggest that the up-regulation of alpha 1-adrenoceptors following repeated antidepressant treatment is not a general phenomenon within the central nervous system.