Increased serotonin2 (5-HT2) receptor binding as measured by 3H-lysergic acid diethylamide (3H-LSD) in the blood platelets of depressed patients

A putative measure of 5-HT2 receptor binding, using 3H-LSD, was compared in blood platelets from 29 depressed patients and 24 normal controls. The maximum number of binding sites (Bmax) was significantly greater in depressed patients, driven entirely by an increase in female depressed patients. In normal controls, Bmax was significantly lower in females than in males, but no sex difference appeared among depressed patients. The binding affinity (Kd) did not differ between groups. Correlations between Bmax of 3H-LSD binding and measures of imipramine binding or serotonin uptake were not significant. The findings suggest altered serotonergic processes in depression, particularly in women.

Study at a glance

Abstract

3H-Lysergic acid diethylamide (3H-LSD) binding, a putative measure of 5-HT2 receptor binding, was studied in the blood platelets of 29 depressed patients and 24 normal controls. The Bmax (maximum number of 3H-LSD binding sites) in the blood platelets of depressed patients was significantly greater than that of normal volunteers. This increase in Bmax was due to an increase in female depressed patients only. Bmax was significantly lower in female compared to male normal controls but there was no difference between male and female depressed patients. There was also no difference in Kd (an inverse measure of affinity of 3H-LSD binding to its sites) between normal controls and depressed patients. The correlations between Bmax of 3H-LSD binding and the Bmax of the 3H-imipramine binding site or the Vmax of 5-HT uptake sites were not significant. The role of serotonergic processes in the psychobiology of depression is discussed.