title: [Characteristics of transmembrane potential of newborn rat cardiomyoblasts which have been cultivated for one week].
abstract: The effect of different media on transmembrane potentials and dV/dt of 7-day cultured rat heart cells was studied by means of microelectrodes. The cells appeared sensitive to K& variations, very sensitive to MnC12 and decreased Ca2&, sensitive to lack of serum and oxygen but quite insensitive to lack of glucose and relatively insensitive to tetrodotoxin. These observations suggest that action potentials are principally due to slow inward current. The cells never responded to decreased Na& by decreasing dV/dt but by depolarizing the membrane. It seems therefore that Ca2 ion plays the most essential role in the genesis of action potential and that the rapid sodium channel is relatively unimportant in case of cardiomyoblasts.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D002712:Chlorides / Q000494:pharmacology; D006321:Heart / Q000502:physiology*; D008345:Manganese / Q000494:pharmacology; D008564:Membrane Potentials; D011188:Potassium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D002712:Chlorides; D008345:Manganese; D013779:Tetrodotoxin; D011188:Potassium; D002118:Calcium
vernacular_title: Caractéristiques des potentiels transmembranaires des cardiomyoblastes de rat nouveau-né, cultivés depuis une semaine