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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
10:53

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents

Published on: July 3, 2013

Functional significance of angiotensin receptors in human myocardium. Significant differences between atrial and

C Holubarsch1, S Schmidt-Schweda, A Knorr

  • 1Department of Cardiology and Angiology, University of Freiburg, Germany.

European Heart Journal
|December 1, 1994
PubMed

Insights

Angiotensin (Ang) I and II significantly increased human atrial muscle force, an effect blocked by saralasine. These peptides did not impact ventricular contractility, indicating specific atrial effects mediated by AT1 receptors.

Area of Science:

  • Cardiovascular Physiology
  • Pharmacology
  • Human Cardiac Tissue Studies

Background:

  • The renin-angiotensin system plays a crucial role in cardiovascular regulation.
  • Understanding the specific effects of angiotensin peptides on human heart muscle is vital for cardiovascular research.

Purpose of the Study:

  • To investigate the inotropic effects of angiotensin I and II on isolated human cardiac tissues.
  • To determine the receptor subtypes mediating these effects in human atrial tissue.

Main Methods:

  • Isolated human atrial and ventricular muscle preparations were studied under physiological conditions.
  • The effects of angiotensin I and II on developed force were measured.
  • Receptor blockade was employed using saralasine, prazosin, and propranolol to identify mediating pathways.

Main Results:

  • Angiotensin I and II increased peak developed force in human atrial muscles by 30-40%.
  • This positive inotropic effect was abolished by saralasine, indicating angiotensin receptor involvement.
  • No significant inotropic effects of Angiotensin I or II were observed in human ventricular preparations.

Conclusions:

  • Angiotensin I and II exert a positive inotropic effect specifically on human atrial muscle.
  • The observed atrial effects are mediated predominantly by the AT1 receptor subtype.
  • Angiotensin peptides do not significantly influence contractility in human ventricular tissues.

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