الکتروشوک درمانی موثر برعکس اختلال گلوتامات/گلوتامین در قدامی چپ از افراد افسرده تک قطبی

Cortical glutamate/glutamine (Glx) metabolism seems to be affected by a major depressive disorder. Recently, a Glx deficit was detected by proton magnetic resonance spectroscopy (1H-MRS) in the bilateral anterior cingulum of depressives. The aim of this study was to assess the effect of successful electroconvulsive therapy (ECT) on Glx levels in the anterior cingulum. The left anterior cingulum of 17 severely depressed unipolar patients was measured by 1H STEAM spectroscopy before and after ECT, and the results were compared with those for 17 age- and gender-matched controls. We observed significantly reduced Glx levels in the patients’ left cingulum compared to healthy controls. In ECT responders, in contrast to non-responders, Glx levels normalized (P=0.04) and then did not differ statistically from controls. Severe depression seems to be associated with a Glx deficit and increasing Glx may be an important mechanism of ECT action.

There is some evidence drawn from neurochemical studies that severe depression is accompanied by perturbation of the metabolism of excitatory amino acids, especially of glutamate (Glu) (Altamura et al., 1993). Normal glutamate metabolism depends on intact neuronal and glial cell function (Gallo and Ghiani, 2000 and Magistretti et al., 1999). Both cell types showed distinct histomorphological alterations in the anterior cingulum of depressives (Ongur et al., 1998 and Rajkowska, 2000). Recently, a significant reduction of glutamate/glutamine (Glx) in the bilateral anterior cingulum in severely depressed patients was demonstrated by means of proton magnetic resonance spectroscopy (1H-MRS) (Auer et al., 2000). MRS provides a unique opportunity to assess brain metabolite levels in vivo (Maier, 1995). If reduced Glx metabolism were pivotal for depression, effective electroconvulsive therapy (ECT), well known for its strong antidepressive effect, should be able to reverse the Glx deficit. We, therefore, investigated 17 severely depressed patients referred for ECT due to treatment resistance. MRS was used to assess metabolic changes in the left anterior cingulum before and after ECT. The left cingulum was chosen, since it was demonstrated by Drevets et al. (1997) that abnormalities in metabolism are left lateralized and we, therefore, expected effects of ECT on glutamate metabolism to be pronounced in this region.