Cytochalasin D as excitation-contraction uncoupler for optically mapping action potentials in wedges of ventricular myocardium

Jiashin Wu, Martin Biermann, Michael Rubart, Douglas P. Zipes

Research output: Contribution to journalArticle

79 Scopus citations


Introduction: Cytochalasin D in tissue bath superfusate inhibits the contraction of isolated thin trabeculae from canine right ventricle without affecting the intracellular action potential recorded with glass microelectrode. The purpose of this study was to test whether cytochalasin D could also be used to immobilize perfused wedges of ventricular muscle without affecting the action potential duration or propagation, and also to determine the optimal concentration and time duration of drug in the perfusate. Methods and Results: Using a membrane potential sensitive dye, di- 4-ANEPPS, and a high-resolution photodiode optical mapping system at a rate of 1,000 frames/sec, we recorded action potentials on the transmural surface of arterially perfused wedges of muscle from the canine left ventricular free wall. We also recorded arterial pulse pressure as a surrogate for tissue contraction. Cytochalasin D at ≥20 μmol/L in the perfusate for ≥6 minutes reduced the arterial pulse pressure to approximately one tenth of its initial value and significantly reduced or eliminated motion artifacts in the action potentials. A sustained concentration of 10 μmol/L cytochalasin D in the perfusate prevented contraction from recurring after the tissue was immobilized with an initial concentration of 25 μmol/L. Cytochalasin D had little effect on the action potential duration and on its transmural gradient, and did not slow the transmural velocity of excitation propagation. Conclusion: Cytochalasin D can be used to uncouple excitation and contraction in perfused canine cardiac muscle for the fluorescent-optical mapping of action potentials without affecting action potential duration or slowing transmural propagation.

Original languageEnglish (US)
Pages (from-to)1336-1347
Number of pages12
JournalJournal of cardiovascular electrophysiology
Issue number12
StatePublished - Jan 1 1998


  • Action potential duration
  • Fluorescent mapping
  • M cell
  • Perfusion
  • Propagation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology

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