title: Autoradiographic localization and analysis of endothelin-1 binding sites in human synovial tissue.
abstract: OBJECTIVE
  To determine the localization of endothelin binding sites and immunoreactivity in human synovial tissues.
  
  
  METHODS
  Quantitative in vitro autoradiographic and immunohistochemical techniques were used to localize and characterize 125I-labeled endothelin-1 (125I-ET-1) binding sites and endothelin-like immunoreactivity in sections of rheumatoid, osteoarthritic, and normal synovium.
  
  
  RESULTS
  Specific 125I-ET-1-binding sites, characteristic of the ETA receptor, were localized to the media of synovial blood vessels in all 3 groups. No difference was found in vascular binding site density in rheumatoid and osteoarthritic synovium. Endothelin-like immunoreactivity was localized to endothelial cells in blood vessels displaying 125I-ET-1 binding sites.
  
  
  CONCLUSIONS
  We conclude that endothelin may act locally, modulating synovial perfusion and exacerbating hypoxia in chronic arthritis.
authors.affiliation: Department of Histochemistry, Royal Postgraduate Medical School, London, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Wharton
authors.forename: R A
authors.initials: RA
authors.lastname: Rutherford
authors.forename: D A
authors.initials: DA
authors.lastname: Walsh
authors.forename: P I
authors.initials: PI
authors.lastname: Mapp
authors.forename: G A
authors.initials: GA
authors.lastname: Knock
authors.forename: D R
authors.initials: DR
authors.lastname: Blake
authors.forename: J M
authors.initials: JM
authors.lastname: Polak
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology; D001345:Autoradiography; D001665:Binding Sites; D016232:Endothelins / Q000032:analysis* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology; D013583:Synovial Membrane / Q000098:blood supply / Q000737:chemistry* / Q000473:pathology
chemical_list: D016232:Endothelins; D007457:Iodine Radioisotopes