Studies on possible mechanisms of action of electroconvulsive therapy; effects of repeated electrically induced seizures on rat brain receptors for monoamines and other neurotransmitters.

There is evidence that repeated electroconvulsive shocks (ECS) in rats potentiate dopamine (DA)-, serotonin (5HT)- and alpha-noradrenergic (alpha-NA)-mediated drug-induced behaviour and reduce opiate-induced behaviours. These studies suggest changes at the level of the receptor or beyond. However, high affinity in vitro 3H-ligand binding studies in brain membranes from ECS-treated control rats failed to demonstrate generalized ECS-induced changes in 5HT, DA, alpha-NA or opiate receptor binding. Binding of the beta-receptor ligand dihydroalprenolol (3H-DHA) was significantly reduced in ECS-treated rat brain membranes. This may be secondary to effects on NA neurones since ECS-induced reduction of 3H-DHA binding did not occur in animals with 6-hydroxydopamine-induced depletion of cortical noradrenaline. In conjunction with other studies, the results suggest that electroconvulsive therapy may have a noradrenergic mechanism of action.