title: Decreased density of serotonin 5-HT2A receptors in rheumatoid arthritis.
abstract: 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.
authors.affiliation: Division of Clinical Pharmacology, Umeå University Hospital, S-901 85 Umeå, Sweden. anders.kling@pharm.umu.se
authors.forename: A
authors.initials: A
authors.lastname: Kling
authors.forename: S
authors.initials: S
authors.lastname: Rantapää-Dahlqvist
authors.forename: H
authors.initials: H
authors.lastname: Stenlund
authors.forename: T
authors.initials: T
authors.lastname: Mjörndal
mesh_terms: 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
chemical_list: D044402:Receptor, Serotonin, 5-HT2A