Electroconvulsive therapy and receptor sensitivity

Administration to rats of one electroconvulsion daily for seven days (ECS × VII) resulted in enhanced behavioural responses to dopamine (DA) agonists and enhanced growth hormone (GH) secretion after treatment with reserpine followed by the DA agonist apomorphine and the noradrenaline (NA) agonist clonidine. The GH response to reserpine followed by clonidine alone was unaffected by pretreatment with ECS × VII. The enhancements, which in animals persist for at least ten days, indicate increased responsiveness in DA sensitive structures. Subsequent investigations in other laboratories have found no changes in either DA‐binding sites or in the DA activated adenylate cyclase system after repeated ECS. The treatment must therefore be assumed to engage structures connected to the DA receptors rather than the receptors themselves. The hGH response was studied in depressed patients before and after electroconvulsive therapy (ECT) and twice also in a control group, where the subjects received no treatment between the two investigations. ECT induced no unitary change in hGH responses. The intra‐individual variation was however significantly greater in the ECT treated patients than in the controls. Eight parkinsonian patients with partial therapy resistence to L‐DOPA were administered ECT during maintenance of their L‐DOPA therapy. Six out of 8 patients improved with respect to their extrapyramidal symptoms. The improvement after ECT was significantly correlated to the duration of the L‐DOPA therapy but not to the degree of mental depression. The results indicate that changes, related to DA receptors, also develop when ECT is administered clinically.