O. Spigset et T. Mjorndal, EFFECT OF FLUVOXAMINE ON PLATELET 5-HT2A RECEPTORS AS STUDIED BY [H-3] LYSERGIC-ACID DIETHYLAMIDE ([H-3]LSD) BINDING IN HEALTHY-VOLUNTEERS, Psychopharmacology, 133(1), 1997, pp. 39-42
Alterations in platelet 5-HT2A receptor characteristics have been repo
rted in major depression as well as in other psychiatric diseases, and
some effort has been made to utilize platelet 5-HT2A receptor status
as a biological correlate to antidepressant drug response. In order to
investigate whether treatment with a selective serotonin reuptake inh
ibitor affects platelet 5-HT2A receptors, we have studied platelet [H-
3]lysergic acid diethylamide ([H-3]LSD) binding in healthy subjects tr
eated with fluvoxamine in increasing dosage once weekly for 4 weeks. A
fter 1 week of fluvoxamine treatment (25 mg/day), both B-max and K-d w
ere significantly lower than before the start of the treatment (19.9 v
ersus 25.5 fmol/mg protein, P = 0.005 for B-max; 0.45 versus 0.93 nM,
P = 0.006 for K-d) B-max returned to baseline during week 2, whereas K
-d was lower than the baseline value throughout the treatment period.
After discontinuation of fluvoxamine treatment, there was a significan
t increase in K-d (0.50 nM before discontinuation vs. 1.14 nM after di
scontinuation; P = 0.001), but not in B-max. The study demonstrates th
at fluvoxamine affects platelet 5-HT2A receptor status irrespective of
underlying psychiatric disease, and that this effect is evident alrea
dy after 1 week at a subtherapeutic fluvoxamine dose.