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Isolation of Atrial Myocytes from Adult Mice
08:34

Isolation of Atrial Myocytes from Adult Mice

Published on: July 25, 2019

Requisite role of cardiac myocytes in coronary alpha1-adrenergic constriction

C P Tiefenbacher1, D V DeFily, W M Chilian

  • 1Department of Physiology, Medical College of Wisconsin, Milwaukee 53226, USA.

Circulation
|July 17, 1998
PubMed

Insights

Cardiac myocytes play a key role in alpha1-adrenergic coronary arteriolar constriction. Myocyte-released factors, potentially including endothelin-1, mediate this response, unlike direct stimulation of microvessels.

Area of Science:

  • Cardiovascular Physiology
  • Vascular Biology
  • Adrenergic Signaling

Background:

  • Alpha-adrenergic activation typically constricts coronary arterioles in vivo.
  • Isolated coronary microvessels paradoxically do not contract to alpha1-adrenergic stimuli in vitro.

Purpose of the Study:

  • To investigate the role of cardiac myocytes in alpha1-adrenergic coronary arteriolar constriction.
  • To identify potential myocyte-derived factors mediating this vasoconstriction.

Main Methods:

  • Isolated coronary arterioles were exposed to phenylephrine or supernatant from phenylephrine-treated cardiac myocytes.
  • Antagonists for endothelin-A and alpha-adrenergic receptors were used.
  • Adenosine antagonist was administered.
  • Endothelin-1 levels in myocyte supernatant were measured.

Main Results:

  • Phenylephrine did not constrict isolated arterioles directly.
  • Supernatant from treated myocytes induced arteriolar constriction.
  • Constriction was blocked by endothelin-A and alpha-adrenergic antagonists.
  • Adenosine antagonism augmented constriction.
  • Phenylephrine increased myocyte endothelin-1 to subthreshold levels.

Conclusions:

  • Cardiac myocytes are essential for alpha1-adrenergic coronary resistance vessel constriction.
  • The mechanism may involve endothelin-1 and other unidentified myocyte-derived vasoconstrictors.
Abstract

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