Manganese action potentials in mammalian cardiac muscle.
The membrane potential in guinea-pig's papillary muscles from right ventricle was recorded by glass microelectrodes and stimulation was effected by current pulses applied through a sucrose-gap. Action potentials with overshoot were recorded in the solution lacking Na+ and Ca++ but containing 2-95 mM Mn++. The overshoot was increased with the increase of [Mn++]o by about 30 mV/decade. Similar Mn++ dependent action potentials were also obtained in Na-free solution containing 0.6 mM Ca++. The results indicate that Mn inward current is sufficient to generate action potentials in cardiac muscle.
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D008345:Manganese / Q000494:pharmacology*; D010210:Papillary Muscles / Q000502:physiology; D012964:Sodium / Q000494:pharmacology
D008345:Manganese; D012964:Sodium; D002118:Calcium