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-HT2 receptor status in mania.


METHODS
We determined density (Bmax) and dissociation constant (Kd) of 5-HT2 receptors in the platelets of 29 normal control and 29 manic subjects using 125I-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 Bmax (3.51 +/- 3.04 vs. 3.14 +/- 3.44 fmol/mg protein, p = ms) values between normal control and manic subjects. In comparison to the baseline values Bmax at day 14 (3.49 +/- 3.68 vs. 2.18 +/- 1.90 fmol/mg protein, p = ns) and following recovery (1.17 +/- 0.85 vs. 1.29 +/- 1.13 fmol/mg protein, p = ns) did not show any significant difference.


CONCLUSIONS
Our findings preliminarily suggest that the platelet 5-HT2 receptor is neither a state marker nor a trait marker in mania; however studies on the 5-HT2 receptor using positron-emission tomography ligands will help in conclusively ruling out the involvement of this receptor in mania.
Velayudhan
A
A
Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India.
Sunitha
T A
TA
Balachander
S
S
Reddy
J Y
JY
Khanna
S
S
D000328:Adult; D001714:Bipolar Disorder / Q000097:blood* / Q000175:diagnosis; D001792:Blood Platelets / Q000737:chemistry*; D010054:Brief Psychiatric Rating Scale; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D007650:Ketanserin; D008297:Male; D011985:Receptors, Serotonin / Q000032:analysis*; D012702:Serotonin Antagonists; D014055:Tomography, Emission-Computed
D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D007650:Ketanserin