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FK506 does not affect cardiac contractility and adrenergic response in vitro

H Milting1, P M Janssen, T Wangemann

  • 1Martin-Luther-Universität Halle-Wittenberg, Clinic for Cardiothoracic Surgery, Research Laboratory, Ernst Grube Str. 40, D-06120, Halle an der Saale, Germany. hmilting@hdz-nrw.de

European Journal of Pharmacology
|November 17, 2001
PubMed

Insights

FK506 (tacrolimus) does not directly impact heart muscle contraction. This study found no positive or negative inotropic effects of FK506 on human and rabbit heart muscle preparations.

Area of Science:

  • Cardiology
  • Pharmacology
  • Immunology

Background:

  • FK506 (tacrolimus) is an immunosuppressant used in heart transplantation.
  • The inotropic effects of FK506 on cardiac muscle are not well understood.
  • FK506 binds to FKBP proteins, which are associated with cardiac calcium release channels.

Purpose of the Study:

  • To investigate the direct inotropic effect of FK506 on isolated human and rabbit cardiac muscle preparations.
  • To determine if FK506 alters myocardial contractility.

Main Methods:

  • Experiments utilized isolated right atrial muscle strips from human myocardium and right ventricular trabeculae from rabbit hearts.
  • Muscle preparations were electrically stimulated and exposed to varying concentrations of FK506.
  • Dose-response curves were generated using isoprenaline as a beta-adrenoceptor agonist.

Main Results:

  • FK506 exposure did not induce any positive or negative inotropic effects in human myocardium.
  • FK506 exposure did not induce any positive or negative inotropic effects in rabbit myocardium.

Conclusions:

  • FK506 does not exert a direct inotropic influence on cardiac muscle.
  • The findings suggest FK506's role in cardiac transplantation is not mediated by direct effects on myocardial contractility.

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