Electrophysiologic effects of exogenous phosphocreatine in cardiac tissue: Potential antiarrhythmic actions

Leonid V. Rosenshtraukh, Richard C. Witt, Patrick N. Nance, George J. Rozanski

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The cellular electrophysiologic effects of exogenous phosphocreatine (PCr) were analyzed to ascertain its purported antiarrhythmic properties during myocardial ischemia and reperfusion. Transmembrane potentials were recorded from isolated guinea pig papillary muscles and Purkinje fibers studied in vitro. Under control, normoxic conditions, 10 mmol/L PCr significantly increased the action potential duration (measured at 90% of repolarization) in ventricular muscle by 14.6 ± 3.3 msec and the effective refractory period by 11.5 ± 3.8 msec (both p < 0.01). Under ischemic-like conditions (hypoxia, lactic acidosis, elevated [K+]o, zero substrate) PCr had no effect. Phosphocreatinine, a related compound that is not a direct substrate in the creatine kinase reaction, acted similarly to PCr suggesting that siterations induced by PCr did not involve a change in the energy state of cells. However, PCr reduced free [Ca2+]o by nearly 20%, and its electrical effects under normoxic conditions could be largely reversed by a concomitant 20% increase in [Ca2+]o. In Purkinje fibers superfused with low [K+]o-Tyrode's solution to elicit conditions of Ca2+ overload, delayed afterdepolarizations and triggered responses were reversibly inhibited by PCr. These data suggest that the antiarrhythmic effects of PCr in situ may involve prolongation of the effective refractory period in nonischemic tissue or attenuation of membrane changes elicited by Ca2+ overload in ischemic cells. The mechanism by which PCr produces these effects may be related in part to changes in extracellular Ca2+ composition.

Original languageEnglish (US)
Pages (from-to)1111-1119
Number of pages9
JournalAmerican Heart Journal
Volume120
Issue number5
DOIs
StatePublished - Nov 1990

Fingerprint

Phosphocreatine
Action Potentials
Purkinje Fibers
Lactic Acidosis
Myocardial Reperfusion
Papillary Muscles
Creatine Kinase
Membrane Potentials
Myocardial Ischemia
Guinea Pigs
Muscles
Membranes

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Electrophysiologic effects of exogenous phosphocreatine in cardiac tissue : Potential antiarrhythmic actions. / Rosenshtraukh, Leonid V.; Witt, Richard C.; Nance, Patrick N.; Rozanski, George J.

In: American Heart Journal, Vol. 120, No. 5, 11.1990, p. 1111-1119.

Research output: Contribution to journalArticle

Rosenshtraukh, Leonid V. ; Witt, Richard C. ; Nance, Patrick N. ; Rozanski, George J. / Electrophysiologic effects of exogenous phosphocreatine in cardiac tissue : Potential antiarrhythmic actions. In: American Heart Journal. 1990 ; Vol. 120, No. 5. pp. 1111-1119.
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