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Immunolocalization of K ATP channel subunits in human radial artery
Author(s) -
Tunstall Radhika R,
GrazulBilska Anna,
O'Rourke Stephen T
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.912.28
Subject(s) - vascular smooth muscle , coronary arteries , restenosis , sirolimus , western blot , confocal microscopy , artery , chemistry , radial artery , protein subunit , anatomy , microbiology and biotechnology , medicine , smooth muscle , biology , biochemistry , stent , gene
Sirolimus is an antiproliferative and immunosuppressant agent that is widely used to prevent restenosis in drug eluting stents. Though little is known about its effects on vasomotor tone, previous studies in our lab demonstrated that sirolimus causes relaxation of isolated human arteries. This response is blocked by glyburide, suggesting a role for K ATP channels in sirolimus‐induced vasorelaxation. To more fully explore the mechanism underlying the smooth muscle relaxing effect of sirolimus, the present study was designed to investigate the expression and localization of K ATP channel subunits in human radial arteries. Radial artery segments were obtained from patients undergoing coronary artery bypass graft surgery and prepared for immunohistochemistry and immunoblot studies. Expression of Kir 6.1, Kir 6.2 and SUR 2A, SUR 2B subunit proteins was detected by Western blot analysis in human radial arteries. Confocal microscopy imaging of cryosections of human radial arteries revealed immunofluorescent labeled K ATP channel subunits in the smooth muscle layer. Kir 6.1 and Kir 6.2 subunits co‐localized with SUR 2 subunits in smooth muscle cells labeled with a fluorescent antibody to smooth muscle actin. These results indicate that human radial artery smooth muscle cells express K ATP channels, which may mediate the vasorelaxant effect of sirolimus in human arteries. (Supported by American Heart Association)