Regulation of the cAMP-Dependent Chloride Current in Cardiac Ventricular Myocytes

  • Robert D. Harvey
  • Jonas A. Jurevičius
  • Joseph R. Hume
Conference paper
Part of the NATO ASI Series book series (volume 60)

Abstract

The contribution, if any, of Cl to the electrical activity in cardiac muscle has been debated since the first reports that altering the extracellular Cl concentration caused changes in the shape of the action potential and rate of spontaneous depolarization in Purkinje fibers (Nutter and Noble, 1961; Carmeliet, 1961). However, it was not until recently that conclusive evidence for a cardiac Cl conductance was found in ventricular myocytes (Harvey and Hume, 1989a; Bahinski et al., 1989). One reason it took so long to discover this Cl current may be explained by the unusual way it is regulated. In isolated myocytes, the Cl current does not appear to be activated unless intracellular cAMP is elevated above basal levels (Harvey and Hume, 1989a; Bahinski et al., 1989), which is a unique feature among ion channels in cardiac tissue. Another unusual characteristic of this Cl current is the fact it exhibits an unexpected dependence on Na+ Early observations found that replacement of extracellular Na+ attenuated the Cl current activated by ß-adrenergic stimulation without affecting its reversal potential (Bahinski et al, 1989; Harvey et al., 1990), suggesting that the ß-adrenergic induced current was Na+-sensitive, but not conducted by Na+ The purpose of the present report is to describe work that has been carried out to identify mechanisms involved in the regulation of the cAMP-dependent Cl current found in cardiac myocytes.

Keywords

Lithium Attenuation Adenosine Histamine Epinephrine 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • Robert D. Harvey
    • 2
  • Jonas A. Jurevičius
    • 1
    • 2
  • Joseph R. Hume
    • 2
  1. 1.Z. Januškevičius Institute of CardiologyKaunasLithuania
  2. 2.Department of PhysiologyUniversity of Nevada School of MedicineRenoUSA

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