Action-potential duration and contractility in canine cardiac tissues action of inotropic drugs

P. Nánási, A. Varró, David A. Lathrop

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Inotropic and electrophysiologic effects of veratrine, vesnarinone, d-sotalol and tetraethylammonium (TEA) were compared. Action-potential duration (APD) and contractility were measured in isolated canine Purkinje fiber and ventricular trabecular muscle preparations by using standard microelectrode techniques. Each drug significantly increased APD and force development in either tissue.Drug-induced increases in force development were normalized to increases in APD. The order of efficacy was found to be vesnarinone>veratrine>TEA in ventricular myocardium, whereas it was veratrine>>vesnarinone=d-sotalol=TEA in Purkinje fibers.The force-APD relation was linear for all drugs in the concentrations used.Simultaneous measurements of APD, force development and intracellular sodium ion activity (a(i)(Na)) in the presence of either veratrine or lidocaine indicated a linear relation between force development and changes in a(i)(Na).The relation between APD and force development was different in ventricular and Purkinje fiber preparations. Differences in the veratrine sensitivity of the force-APD relation observed between Purkinje and ventricular preparations suggest that a(i)(Na)-dependent changes in Na+/Ca2+ exchange may play a more important role in regulation of force generation in Purkinje fibers than in ventricular myocardium. Copyright (C) 1998 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)415-418
Number of pages4
JournalGeneral Pharmacology
Volume31
Issue number3
DOIs
Publication statusPublished - Sep 1998

Fingerprint

Veratrine
Action Potentials
Canidae
Purkinje Fibers
Tetraethylammonium
Pharmaceutical Preparations
Sotalol
Myocardium
Microelectrodes
Lidocaine
Sodium
Ions
Muscles
vesnarinone

Keywords

  • Action-potential duration
  • Cardiac muscle
  • Contractility
  • Electrophysiology
  • Intracellular sodium ion activity
  • Purkinje fibers

ASJC Scopus subject areas

  • Pharmacology

Cite this

Action-potential duration and contractility in canine cardiac tissues action of inotropic drugs. / Nánási, P.; Varró, A.; Lathrop, David A.

In: General Pharmacology, Vol. 31, No. 3, 09.1998, p. 415-418.

Research output: Contribution to journalArticle

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