Further observations on the effect of repeated electroconvulsive shock on the behavioural resposes of rats produced by increases in the functional activity of brain 5-hydroxytryptamine and dopamine

Following repeated electroconvulsive shocks (ECS) (once daily for 10 days), rats display enhanced hyperactivity responses to tranylcypromine and l-tryptophan, a procedure which increases brain 5-hydroxytryptamine (5-HT) concentrations, or to the suggested 5-HT agonist quipazine. The enhanced responses last for about 6 days following the last shock. Repeated sub-convulsive shocks did not produce this behavioural enhancement.Administration of indomethacin (2 mg/kg) 25 min before the ECS did not prevent the enhanced 5-HT response suggesting that the enhanced response is not the result of the reported rise in prostaglandins F following ECS.Repeated ECS shortened the time to loss of righting following pentobarbital (50 mg/kg) but did not alter the total sleeping time.Repeated ECS enhances locomotor activity produced by methamphetamine. It also enhances circling produced by methamphetamine and apomorphine in unilateral nigrostriatal lesioned rats, suggesting an enhanced postsynaptic response.No evidence was found for ECS altering the response of striatal adenylate cyclase to dopamine nor for any alteration of striatal cyclic AMP concentration.These data taken with our previous study reinforce the suggestion that electroconvulsive therapy (ECT) produces increased responses to 5-hydroxytryptamine and dopamine receptor stimulation.