A study of platelet serotonin receptor in mania

Background: Serotonergic (5-HT) dysfunction has been hypothesized in mania; however platelet studies on the 5-HT uptake rate and the 5-HT transporter have revealed inconsistent results. To the best of our knowledge no studies have been conducted on the 5-HT, receptor status in mania. Methods: We determined density (B-max) and dissociation constant (K-d) of 5 -HT2 receptors in the platelets of 29 normal control and 29 manic subjects using I-125-ketanserin as the binding radioligand. The manic patients were assessed for the same after 14 days of treatment with lithium (n = 14) and after return to premorbid levels of functioning (n = 5). Results: There were no significant differences in the B-max (3.51 +/- 3.04 vs. 3.14 +/- 3.44 fmol/mg protein, p = ms) values between normal control an d manic subjects. In comparison to the baseline values B-max at day 14 (3.4 9 +/- 3.68 vs, 2.18 +/- 1.90 fmol/mg protein, p = ns) and following recover y (1.17 +/- 0.85 vs. 1.29 +/- 1.13 fmol/mg protein, p = ns) did not show an y significant difference. Conclusions: Our findings preliminarily suggest that the platelet 5-HT2 rec eptor is neither a state marker nor a trait marker in mania; however studie s on the 5-HT, receptor using positron-emission tomography ligands will hel p in conclusively ruling out the involvement of this receptor in mania, (C) 1999 Society of Biological Psychiatry.