1
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Effects of nitroglycerin on the coronary microcirculation in normal and ischemic myocardium.

      Read this article at

      ScienceOpenPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Nitroglycerin dilates conduit coronary vessels and only transiently increases flow, however the effects of nitroglycerin in the microcirculation of normal myocardium and during myocardial ischemia have not been assessed. The goal of this investigation was to determine the effects of steady-state levels of nitroglycerin on the microcirculation of normal and ischemic myocardium. Microvessels on the left ventricle were viewed using stroboscopic epi-illumination in anesthetized, open-chest dogs. Myocardial perfusion was measured with radioactive microspheres. Aortic pressure and heart rate were kept constant by an aortic snare and left atrial pacing. Microvessel diameters were measured under control conditions and during steady-state infusion of nitroglycerin (n = 11, 0.01-100 micrograms kg-1 min-1, i.v.). Nitroglycerin selectively dilated arteries from 201 to 386 microns, but had no effect on large arterioles less than 200 microns. Total coronary vascular resistance remained constant except at the highest dose. When mean coronary pressure was decreased to 35 mm Hg, small arterioles less than 100 microns dilated. Diameters of larger arterioles decreased. Nitroglycerin (10 micrograms kg-1 min-1, i.v., n = 8) selectively dilated microvessels greater than 200 microns in the region distal to the stenosis, although myocardial perfusion was not affected. Thus, nitroglycerin altered the distribution of microvascular resistance without altering overall resistance. We conclude that steady-state infusion of nitroglycerin selectively dilates coronary arterial microvessels greater than 200 microns. During decreased perfusion pressure, recruitable vasodilation in response to nitroglycerin is due to dilation of microvessels greater than 200 microns.

          Related collections

          Author and article information

          Journal
          J. Cardiovasc. Pharmacol.
          Journal of cardiovascular pharmacology
          0160-2446
          0160-2446
          May 1992
          : 19
          : 5
          Affiliations
          [1 ] Tohoku University Hospital, 1st Department of Internal Medicine, Sendai, Japan.
          Article
          1381774
          63cdd53c-4484-4bd3-abf9-03c15d60ff4b
          History

          Comments

          Comment on this article