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

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