Studies on serotonergic markers in the human hippocampus: changes in subjects with bipolar disorder

Abstract

Background: Various studies suggest the hippocampus and serotonergic systems are important in the pathology of bipolar disorder (BD). We therefore measured hippocampal serotonergic markers in post-mortem tissue from BD and control subjects.

Methods: The density and affinity of [3H]citalopram binding to the serotonin transporter (SERT), as well as the density of the 5HT(2A), 5HT(1A), 5HT(1D) and 5HT(1F) receptors were measured.

Results: The density of SERT and 5HT receptors was no different in BD. There was a significant decrease in the affinity of [3H]citalopram binding to SERT in the stratum lacunosum-moleculare (S(lac)) in BD (K(d) mean+/-S.E.M.=4.3+/-0.8 vs. 1.9+/-0.3 nM).

Limitations: This study was completed using relatively small cohorts.

Conclusions: There are no generalised changes in hippocampal serotonergic markers in the hippocampus from subjects with BD. There is a decreased affinity of radioligand binding to S(lac) SERT in subjects with BD.