Effect of electroconvulsive therapy on 5-HT1A receptor binding in patients with depression: a PET study with [11C]WAY 100635.

In our previous positron emission tomography (PET) study, we demonstrated that ECT decreased dopamine D2 receptor in major depressive disorder (MDD). Although many animal studies have focused on the effect of ECT on serotonergic neurotransmission, no human study has directly examined the effect of ECT on brain serotonin [5-hydroxytryptamine (5-HT)] 1A receptors (5-HT1ARs). Using PET with [11C]WAY 100635, we aimed to evaluate the effect of ECT on 5-HT1ARs in patients with MDD. Nine patients underwent PET scans before and after a series of 6-7 bilateral ECTs. Region-of-interest analysis was performed based on the simplified reference tissue model. There were no significant changes in 5-HT1AR binding in patients between before and after ECT. ECT did not alter [11C]WAY 100635 binding even after recovery from depressive episode. Although the present finding does not exclude the involvement of brain 5-HT1A systems in the antidepressant action of ECT, it may indicate the involvement of other neurotransmission mechanisms.