Skip to main content
NCBI home page
British Journal of Pharmacology logoLink to British Journal of Pharmacology
. 1989 Apr;96(4):857–863. doi: 10.1111/j.1476-5381.1989.tb11895.x

Hypoxia- and endothelium-mediated changes in the pharmacological responsiveness of circumflex coronary artery rings from the sheep.

Y W Kwan 1, R M Wadsworth 1, K A Kane 1
PMCID: PMC1854449  PMID: 2472846

Abstract

1. The role(s) of the endothelium in modulating the responsiveness of isolated circumflex coronary artery rings (o.d. = 2.0-2.5 mm and o.d. = 0.6-1.3 mm) from sheep was investigated under oxygenated and hypoxic conditions. 2. Removal of the endothelium abolished the contraction produced by lowering the PO2 from 620 to 8 mmHg (either under optimal resting tension or precontracted by 40 mM KCl). In denuded artery rings sudden hypoxia caused relaxation. 3. Under oxygenated conditions, removal of the endothelium augmented the vasoconstrictor effects of U46619, 5-hydroxytryptamine (5-HT) and K+. In the denuded artery rings, hypoxia abolished the contractile effects of U46619 and reduced the contractile effects of 5-HT and K+. 4. Under oxygenated conditions, the vasorelaxant effect of adenosine was depressed by removal of the endothelium. In endothelium-denuded preparations, the small relaxant effect of adenosine remaining was greatly potentiated. 5. Haemolysate (1 microliter ml-1) caused an endothelium-dependent contraction under oxygenated conditions. The hypoxic contraction observed in the artery ring under resting tension was significantly potentiated by haemolysate (1 microliter ml-1). Haemolysate 1 microliter ml-1 had no effect on the denuded artery rings under hypoxic conditions. 6. Haemolysate (1 microliter ml-1) potentiated the vasoconstrictor effects of U46619 (0.5 microM), 5-HT (1 microM) and K+ (24 mM) under oxygenated conditions. 7. These results indicate that endothelium profoundly modifies the effect of hypoxia on the responsiveness of sheep isolated left circumflex coronary artery rings.

Full text

PDF
857

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Asada Y., Hayashi T., Sumiyoshi A. Vascular injuries induced by materials released from platelet-rich thrombus in vivo. Atherosclerosis. 1988 Mar;70(1-2):1–6. doi: 10.1016/0021-9150(88)90093-7. [DOI] [PubMed] [Google Scholar]
  2. Bolton T. B. Mechanisms of action of transmitters and other substances on smooth muscle. Physiol Rev. 1979 Jul;59(3):606–718. doi: 10.1152/physrev.1979.59.3.606. [DOI] [PubMed] [Google Scholar]
  3. Cherry P. D., Furchgott R. F., Zawadzki J. V., Jothianandan D. Role of endothelial cells in relaxation of isolated arteries by bradykinin. Proc Natl Acad Sci U S A. 1982 Mar;79(6):2106–2110. doi: 10.1073/pnas.79.6.2106. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. De Mey J. G., Claeys M., Vanhoutte P. M. Endothelium-dependent inhibitory effects of acetylcholine, adenosine triphosphate, thrombin and arachidonic acid in the canine femoral artery. J Pharmacol Exp Ther. 1982 Jul;222(1):166–173. [PubMed] [Google Scholar]
  5. Furchgott R. F., Zawadzki J. V. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 1980 Nov 27;288(5789):373–376. doi: 10.1038/288373a0. [DOI] [PubMed] [Google Scholar]
  6. Kwan Y. W., Wadsworth R. M., Kane K. A. Effects of hypoxia on the pharmacological responsiveness of isolated coronary artery rings from the sheep. Br J Pharmacol. 1989 Apr;96(4):849–856. doi: 10.1111/j.1476-5381.1989.tb11894.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Lamping K. G., Marcus M. L., Dole W. P. Removal of the endothelium potentiates canine large coronary artery constrictor responses to 5-hydroxytryptamine in vivo. Circ Res. 1985 Jul;57(1):46–54. doi: 10.1161/01.res.57.1.46. [DOI] [PubMed] [Google Scholar]
  8. Martin W., Villani G. M., Jothianandan D., Furchgott R. F. Selective blockade of endothelium-dependent and glyceryl trinitrate-induced relaxation by hemoglobin and by methylene blue in the rabbit aorta. J Pharmacol Exp Ther. 1985 Mar;232(3):708–716. [PubMed] [Google Scholar]
  9. Morrison A. D., Orci L., Berwick L., Perrelet A., Winegrad A. I. The effects of anoxia on the morphology and composite metabolism of the intact aortic intima-media preparation. J Clin Invest. 1977 Jun;59(6):1027–1037. doi: 10.1172/JCI108725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Rubanyi G. M., Vanhoutte P. M. Hypoxia releases a vasoconstrictor substance from the canine vascular endothelium. J Physiol. 1985 Jul;364:45–56. doi: 10.1113/jphysiol.1985.sp015728. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Rubanyi G., Vanhoutte P. M. Endothelium-removal decreases relaxations of canine coronary arteries caused by beta-adrenergic agonists and adenosine. J Cardiovasc Pharmacol. 1985 Jan-Feb;7(1):139–144. doi: 10.1097/00005344-198501000-00023. [DOI] [PubMed] [Google Scholar]
  12. White T. D., Angus J. A. Relaxant effects of ATP and adenosine on canine large and small coronary arteries in vitro. Eur J Pharmacol. 1987 Nov 3;143(1):119–126. doi: 10.1016/0014-2999(87)90741-2. [DOI] [PubMed] [Google Scholar]

Articles from British Journal of Pharmacology are provided here courtesy of The British Pharmacological Society

RESOURCES