LOCALIZED ALTERATIONS IN PRESYNAPTIC AND POSTSYNAPTIC SEROTONIN BINDING-SITES IN THE VENTROLATERAL PREFRONTAL CORTEX OF SUICIDE VICTIMS

Altered serotonin indices have been reported in the brain of suicide v ictims. We sought to localize the changes in presynaptic and postsynap tic serotonin receptors and identify an area of prefrontal cortex that may influence suicide risk. Quantitative autoradiography was performe d in coronal sections of prefrontal cortex to determine whether seroto nin 5-HT1A receptor (postsynaptic in cortex) and serotonin transporter (presynaptic) binding are different in suicide victims compared to ma tched controls. 5-HT1A receptor binding was higher in 85 of the 103 sa mpled areas in the suicide group (n = 18 pairs; P < 0.0001). The incre ase ranged from 17 to 30%. The increase was more pronounced in the ven trolateral prefrontal cortex. Serotonin transporter binding was found to be lower in the suicide group in all but one of the 43 sampled regi ons (n = 22 pairs; P < 0.0001). The reduction in binding was most pron ounced in the ventrolateral prefrontal cortex, where the difference be tween suicides and controls ranged between 15 and 27%. Serotonin trans porter and 5-HT1A binding were negatively correlated (r = - 0.35 to - 0.44, P = 0.04 to 0.007) within the same brain areas, suggesting commo n regulatory factors with opposite effects on binding to the two recep tors. We conclude that suicide victims have an abnormality in the sero tonin system involving predominantly the ventrolateral prefrontal cort ex, and hypothesize that the serotonergic dysfunction in this brain re gion contributes to the risk for suicidal behavior.