Effect of electroconvulsive treatment on cerebral opioid receptors in the rat: changes in delta but not mu receptors.

The rats subjected to repetitive electroconvulsive treatment (ECT; 8 electroshocks within 9 days) the density of specific 3H-D-Ala2, D-Leu5-enkephalin (3H-DADLE) binding sites in the cortical membranes was enhanced by approx. 60%, while the density of specific 3H-naloxone binding sites remained unchanged. In the striatum of rats subjected to ECT the specific binding of 3H-DADLE was reduced by 15%, and no change in 3H-naloxone binding was observed. The density of specific binding sites for either radioligand in the rest of brain remained unaffected by ECT. The results suggest that ECT affects specifically the opioid delta receptors in some brain areas.