Unaltered number of brain serotonin uptake sites in suicide victims

Abstract

The 5-HT uptake sites were studied with [3H ] paroxetine as radioligand in frontal cortex, cingulate cortex and hypothalamus from a control group (n=22) and a group of suicide victims (n = 19). The binding was also analysed with regard to the method of suicide (violent or non-violent) and history of depressive symptoms. The apparent dissociation constant (Kd ) was the same, 0.07-0.10 nM, and did not differ between the two groups studied. The maximum number of binding sites ( Bmax) for the controls were frontal cortex 112±21, cingulate gyrus 227±92 and hypothalamus 699±240 fmol/mg protein. The Bmax values for the suicide group were not different from those of the control group. When the binding parameters were analysed according to the method of suicide (violent or non-violent) there were no differences in comparison to the control group or between these two suicide groups. Similarly, suicides with and without history of depression did not differ in [3H ] paroxetine binding and were not different from the control group. The control and suicide groups were not different with respect to age and post- mortem storage time. Considering 5-HT uptake sites as indirect markers for 5-HT terminals, these data suggest that the 5-HT terminal system is intact in the neocortex, the limbic system and in the hypothalamus in suicide victims.