Increased alpha 2-adrenoceptor density in the frontal cortex of depressed suicide victims.

The density of brain alpha 2-adrenoceptors, quantitated by means of the binding of the agonist [3H]clonidine, was studied in post-mortem cortical membranes of matched control subjects and depressed suicide victims. In the depressed suicide group, the specific high affinity binding of [3H]clonidine was found to be significantly increased (Bmax, 72% greater; p less than 0.01) without significant changes in the KD value for the radioligand. These preliminary results indicate that alpha 2-adrenoceptor density in the high affinity state (alpha 2H) is increased in the brain of depressed patients and add strong support to the hypothesis that endogenous depression is related to supersensitive alpha 2-adrenoceptors.