Calcium and cardiac electrophysiology. Some experimental considerations

M. Morad, J. Maylie

Research output: Contribution to journalArticlepeer-review


Electrophysiologic experiments in cardiac tissue suggest that Ca2+ is involved in generation of the action potential, the pacemaker potential, and conduction of the slow wave of depolarization. For instance, removal of Ca2+ inhibits the slow inward current and prolongs the action potential and suppresses the slow diastolic depolarization. Divalant cations Mn2+, Co2+, Cd2+, Mg2+, block the slow inward current and suppress pacemaker activity, but shorten the action potential. Ni2+ specifically blocks the slow inward current and prolongs the action potential. Ca2+ also plays a central role in generation of diastolic depolarization. Cd2+ inhibits the diastolic depolarization and the upstoke of the action potential in SA nodal cells, while blocking the time-dependent inward current in the pacemaker potential range and the time-dependent outward current. A variety of molecular transport systems ranging from the Ca-channel to a Ca2+-Na+ or Ca2+-K+ exchanges to Ca2+-induced activation of the K+ current have been postulated to explain the effects of Ca2+ on cardiac electrophysiologic processes.

Original languageEnglish (US)
Pages (from-to)166-173
Number of pages8
Issue number1 SUPPL.
StatePublished - 1980
Externally publishedYes

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine
  • Cardiology and Cardiovascular Medicine


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