Vasoconstrictor effects of endothelin-1 on myocardium microcirculation studied by the langendorff perfusion method: Differential sensitivities among microvessels

Satoshi Homma, Takashi Miyauchi, Yasuro Sugishita, Katsutoshi Goto, Masaaki Sato, Norio Ohshima

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

An intravital fluorescence microscope system was used to investigate the pharmacological effects of endothelin-1 (ET-1) on the coronary microcirculation in the isolated beating hearts of rats. The heart was perfused by retrograde aortic steady flow with an oxygenated Krebs-Ringer solution containing FITC-dextran. Changes in diameters of coronary microvessels accompanying the cumulative injection of ET-1 in the perfusate were observed and recorded with a video camera system. Coronary perfusion pressure was also measured during each experiment. Bolus injections of ET-1 (1-300 pmole) elicited a dose-dependent increase in perfusion pressure from 54 ± 6 mm Hg (mean ± SEM; n = 10, before the ET-1 injection) to 144 ± 9 mm Hg (n = 8, at the ET-1 dose of 300 pmole). A dose-dependent narrowing of microvessels was also observed. This vasoconstriction was especially prominent in small-sized arterioles; the maximum vasoconstriction of the smaller arterioles was significantly higher than that of the larger arterioles (P < 0.05). The response induced by ET-1 dose of 3-10 pmole was significantly larger in arterioles than in postcapillary venules in the diameter range between 10 and 40 μm. The vasoconstriction produced by ET-1 was inhomogeneous. Some part of bifurcations of arterioles showed a prominent localized vasoconstriction, and occasionally showed a complete luminal obstruction. Such a segmental vasospasm might be attributed to localized sensitivities of arterioles to ET-1. These findings suggest that ET-1 may have an important role in governing the coronary resistance and regulating the capillary flow in the myocardium.

Original languageEnglish
Pages (from-to)205-217
Number of pages13
JournalMicrovascular Research
Volume43
Issue number2
DOIs
Publication statusPublished - 1992 Mar

ASJC Scopus subject areas

  • Biochemistry
  • Cardiology and Cardiovascular Medicine
  • Cell Biology

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