title: Serotonin and its 5-HT1 receptor in human mastocytosis.
abstract: BACKGROUND
  Human mastocytosis is a rare disease, in which the serotonergic system may be involved.
  
  
  OBJECTIVE
  The objective of the present study was to examine the possible presence of serotonin (5-HT) and its 5-HT1A receptor (R) in the skin of patients with mastocytosis. In addition, the effect of the 5-HT1AR was tested on human mastocytosis cells, cultured in vitro.
  
  
  METHODS
  The expression of 5-HT and 5-HT1AR in patients with urticaria pigmentosa and mastocytoma was studied using immunohistochemistry. The effects of 8-OH-DPAT, an agonist of 5-HT1AR, on the proliferation (cell number), viability, apoptosis, spontaneous release of histamine, as well as a possible 5-HT metabolism, in the human HMC-1 mast cell line, were investigated.
  
  
  RESULTS
  Both 5-HT and 5-HT1AR were expressed in the mast cells in biopsies of mastocytoma and urticaria pigmentosa, as well as in HMC-1 cells. However, no metabolism of 5-HT by the cell line could be detected by the methodology used. The 5-HT1AR agonist had no significant effect on the viability and number of HMC-1 cells, and was without effect on the apoptosis. At concentrations of 10⁻⁶ mol/L and 10⁻⁸-10⁻¹⁰ mol/L (i.e. also at physiological concentrations), the agonist inhibited histamine release by these cells by as much as 30%.
  
  
  CONCLUSIONS
  These findings indicate that 5-HT and its 5-HT1AR are expressed in human mastocytosis and that an agonist of the 5-HT1AR might be of value in the treatment of these patients.
authors.affiliation: Dermatology and Venereology Unit, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
authors.forename: Markus
authors.initials: M
authors.lastname: Ritter
authors.forename: Husameldin
authors.initials: H
authors.lastname: El-Nour
authors.forename: Mari-Anne
authors.initials: MA
authors.lastname: Hedblad
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Butterfield
authors.forename: Olof
authors.initials: O
authors.lastname: Beck
authors.forename: Niclaus
authors.initials: N
authors.lastname: Stephanson
authors.forename: Mikael
authors.initials: M
authors.lastname: Holst
authors.forename: Ricardo
authors.initials: R
authors.lastname: Giscombe
authors.forename: Efrain C
authors.initials: EC
authors.lastname: Azmitia
authors.forename: Klas
authors.initials: K
authors.lastname: Nordlind
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000328:Adult; D002460:Cell Line; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D034701:Mastocytosis, Cutaneous; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000276:immunology*; D044282:Receptor, Serotonin, 5-HT1A / Q000096:biosynthesis / Q000276:immunology*; D012701:Serotonin / Q000276:immunology* / Q000378:metabolism; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012867:Skin / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: D009363:Neoplasm Proteins; D017366:Serotonin Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin