No early effects of electroconvulsive therapy on tryptophan metabolism and disposition in endogenous depression

The possibility that a single electroconvulsive therapy (ECT) could increase tryptophan (Trp) availability to the brain for 5-hydroxytryptamine (5-HT, serotonin) synthesis was examined in 10 depressed patients before and during the 1st hour following an ECT and in 4 control (minor ear, nose, and throat surgical) subjects receiving similar premedication. Trp availability to the brain, expressed as the serum Trp: competing amino acid ratio, and related aspects of Trp disposition were not significantly altered by ECT any differently than from preoperative stress and premedication. We suggest that Trp availability to the brain and, hence, cerebral 5-HT synthesis are not altered in depressed patients early after a single ECT.