These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Endothelium-dependent vasodilation of canine coronary collateral vessels.
    Author: Flynn NM, Kenny D, Pelc LR, Warltier DC, Bosnjak ZJ, Kampine JP.
    Journal: Am J Physiol; 1991 Dec; 261(6 Pt 2):H1797-801. PubMed ID: 1750535.
    Abstract:
    The objective of this study was to determine whether endothelium-mediated relaxation occurs in canine coronary collateral vessels. Responses to endothelium-dependent vasodilators in coronary collateral vessels (250-350 microns) were compared with those obtained in normal native coronary arteries of similar size. Rings of small arteries and collateral vessels were suspended in baths, and tension was recorded. All rings were constricted with prostaglandin F2 alpha (3 microM) and subsequently exposed to cumulative concentrations of acetylcholine or bradykinin. In separate experiments, the procedure was repeated in the presence of 300 microM NG-monomethyl-L-arginine (L-NMMA) to inhibit endothelium-mediated vasodilation. Endothelium-dependent relaxation was further studied in the presence of indomethacin, and endothelium-independent relaxation was examined with sodium nitroprusside. Acetylcholine and bradykinin relaxed both normal native and collateral rings. In preconstricted small arteries and collateral vessels the concentration at 50% of maximal response of acetylcholine was 85.5 +/- 19.5 and 61.0 +/- 14.0 microns, and bradykinin was 11.9 +/- 7.4 and 10.7 +/- 2.1 microns, respectively. L-NMMA attenuated the response to acetylcholine and bradykinin in both groups. The results indicate that endothelium is present and functional in canine coronary collateral vessels. Both small coronary arteries and collateral vessels are equally responsive to endothelium-dependent vasodilators and inhibition of endothelium-dependent relaxing factor.
    [Abstract] [Full Text] [Related] [New Search]