Electrogenic Na pump evidenced by injecting various Na salts into the isolated A-V node cells of rabbit heart.
Electrogenicity of the Na pump was confirmed by injecting Na salts into a small cluster of A-V node cells. Injection of Na glutamate or Na acetate induced marked hyperpolarization, accompanying with cessation of spontaneous activity. The hyperpolarization exceeded EK in 27 mM K Tyrode solution and was inhibited by 10(-5) M strophanthidin. Injection of NaCl or NaI depolarized the membrane. These data showed that inward-going current carried by the injected anion antagonized the outward-going pump current and thus determined the net effect of the injection.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001283:Atrioventricular Node / Q000378:metabolism*; D001693:Biological Transport, Active; D004558:Electric Stimulation; D006321:Heart / Q000502:physiology*; D006329:Heart Conduction System / Q000378:metabolism*; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000378:metabolism; D011188:Potassium / Q000502:physiology; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*
D012964:Sodium; D011188:Potassium