Decreased density of serotonin 5-HT2A receptors in rheumatoid arthritis.
BACKGROUND
Animal studies have indicated that 5-HT2A receptors could play a role in arthritic diseases.


OBJECTIVE
To analyse the binding properties of 5-HT2A receptors in patients with rheumatoid arthritis.


METHODS
Using a radioactive binding assay, 43 patients with rheumatoid arthritis were compared with 49 sex and age matched controls for density and affinity (measured as Bmax and Kd) of 5-HT2A serotonin receptors. Genotyping, using polymerase chain reaction, was undertaken to exclude the possibility that differences in the genetic polymorphism T102C for the 5-HT2A receptor determine differences in receptor density.


RESULTS
Mean of Bmax of 5-HT2A receptors in rheumatoid patients was significantly lower than in controls, at 45.3 v 57.4 fmol/mg protein (p = 0.004), but there was no significant difference in Kd. The T102C receptor polymorphism genotypes showed a skewed distribution between the two groups. Even when adjusted for this, there was a significant difference in Bmax between the groups.


CONCLUSIONS
The density of 5-HT2A serotonin receptors in patients with rheumatoid arthritis is markedly reduced. This could either reflect a difference involved in the susceptibility to the disease or be a secondary effect of the disease.
Kling
A
A
Division of Clinical Pharmacology, Umeå University Hospital, S-901 85 Umeå, Sweden. anders.kling@pharm.umu.se
Rantapää-Dahlqvist
S
S
Stenlund
H
H
Mjörndal
T
T
D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D001667:Binding, Competitive; D016022:Case-Control Studies; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011869:Radioligand Assay / Q000379:methods; D044402:Receptor, Serotonin, 5-HT2A / Q000032:analysis* / Q000235:genetics
D044402:Receptor, Serotonin, 5-HT2A