Unaltered Number of Brain Serotonin Uptake Sites in Suicide Victims

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 (K_d ) was the same, 0.07-0.10 nM, and did not differ between the two groups studied. The maximum number of binding sites (B_max) for the controls were frontal cortex 112±21, cingulate gyrus 227±92 and hypothalamus 699±240 fmol/mg protein. The B_max 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.