Background: The involvement of serotonin in depression and suicide has been proposed, because major depression is successfully treated by medications that specifically block the serotonin transporter, and there is evidence for a decrease in serotonin transporters in major depression and suicide. The midbrain dorsal raphe nucleus (DR) has been implicated as a site for diminished serotonergic activity in that suicide victims with major depression have a significant increase in serotonin-1A autoreceptors in the DR.
Methods: [(3)H]Paroxetine was used to label the serotonin transporter in the subnuclei of the DR at several rostral-to-caudal levels of the midbrain in ten pairs of suicide victims with major depression and age-matched psychiatrically normal control subjects.
Results: There was a significant increase in serotonin transporters in the entire DR progressing from rostral-to-caudal levels in both normal control subjects and suicide victims with major depression. At comparable rostral-to-caudal levels, there were no significant differences in [(3)H]paroxetine binding between depressed suicide victims and normal control subjects in either the entire DR or its constituent subnuclei.
Conclusions: The pathophysiology of serotonin mechanisms in suicide victims with major depression does not appear to involve alterations in the binding of [(3)H]paroxetine to the serotonin transporter in the midbrain DR.