Author + information
- Received December 16, 2004
- Revision received March 22, 2005
- Accepted March 29, 2005
- Published online July 19, 2005.
- Bertrand Rozec, MD⁎,†,
- Sabrina Serpillon, PhD⁎,
- Gilles Toumaniantz, PhD⁎,
- Camille Sèze, MSc⁎,
- Yohann Rautureau, PhD‡,
- Olivier Baron, MD§,
- Jacques Noireaud, PhD⁎ and
- Chantal Gauthier, PhD⁎∥,⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Chantal Gauthier, L’Institut du Thorax, UMR533, Faculté de Médecine, 1 rue Gaston Veil, BP 53508, F-44035 Nantes, France
Objectives The aim of the present study was to analyze whether beta3-adrenoceptors (β3-ARs) were effectively present and functional in the human internal mammary artery (IMA).
Background The beta1- and beta2-adrenoceptors classically mediate the relaxant effects of catecholamines in the vessels. In vitro and in vivo studies performed in various animal species described vasodilating effects due to activation of a third beta-ARs subtype (β3).
Methods Reverse transcription-polymerase chain reaction analysis, Western blot experiments, and pharmacological studies were carried out in human IMA samples harvested from 27 patients undergoing coronary bypass surgery.
Results The β3-ARs messenger ribonucleic acid and protein were detected in intact IMA, but were absent in endothelium-free samples. This finding was confirmed by immunohistochemical experiments. In organ baths, a β3-AR agonist, SR 58611A, induced an endothelium-dependent relaxation of phenylephrine-precontracted IMA rings. This vasodilation was not modified by β1/β2-AR antagonists, but was greatly altered in the presence of L-748,337, a selective human β3-AR antagonist. Moreover, the inhibition of nitric oxide (NO) synthases abolished the β3-adrenergic vasodilation, suggesting the involvement of a NO-signaling pathway.
Conclusions Those results demonstrated the presence of β3-ARs in the endothelial layer of human IMA. The present work highlights the role of β3-ARs in vasomotor control of IMA and opens new fields of investigation in coronary bypass graft management, heart failure, and hypertension.
This work was supported by grants from INSERM, the “Fédération Francaise de Cardiologie,” the “Fondation de France,” and the “Fondation Langlois.” Bertrand Rozec was supported by grants from the “Société Francaise d’Anesthésie et de Réanimation” and the “Fondation de la Recherche Médicale.” Sabrina Serpillon was supported by the “Conseil Général de Loire-Atlantique.” Drs. Rozec, Serpillon, and Toumaniantz contributed equally to this work.
- Received December 16, 2004.
- Revision received March 22, 2005.
- Accepted March 29, 2005.
- American College of Cardiology Foundation