Autoradiographic localization and analysis of endothelin-1 binding sites in human synovial tissue.
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.
Wharton
J
J
Department of Histochemistry, Royal Postgraduate Medical School, London, United Kingdom.
Rutherford
R A
RA
Walsh
D A
DA
Mapp
P I
PI
Knock
G A
GA
Blake
D R
DR
Polak
J M
JM
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
D016232:Endothelins; D007457:Iodine Radioisotopes