Brain 5-HT 2 receptor binding sites in depressed suicide victims

Abstract

5-HT 2 receptor binding sites were measured (by saturation binding of [ 3H]ketanserin) in brain tissue obtained at postmortem from 19 suicide victims with definite evidence of depression and 19 sex and age-matched control subjects. Five of the suicide victims were receiving antidepressant drugs prior to death; 13 suicide victims had not been prescribed antidepressant or other psychoactive drugs recently and none were found in their blood at postmortem. The number of serotonin-2 (5-HT 2) binding sites in frontal, temporal and occipital cortex and amygdala did not differ significantly between the depressed suicide victims and controls, either in the total suicide group or in the antidepressant drug-free suicides. The number of 5-HT 2 binding sites in the hippocampus did not differ from controls in the total suicide group but was significantly lower (by 23%) in the antidepressant-free suicide group. The affinity of [ 3H]ketanserin binding did not differ from controls in the antidepressant-free suicides but was lower (increased K d) in those subjects receiving antidepressant drugs. No correlation was found between the time of death and storage of tissue or the duration of tissue storage prior to assay and the number or affinity of 5-HT 2 binding sites. A significant negative correlation was found between age of the subject and the number of 5-HT 2 binding sites in the frontal and occipital cortex. The present study of suicide victims with definite evidence of depression do not confirm previous studies of increased numbers of 5-HT 2 binding sites in suicide victims and suggest that these previous findings may be related to factors other than depression.