Nuclear magnetic resonance studies of sodium/calcium exchange in frog perfused, beating hearts.
This study explores the effect of extracellular Ca2+ concentration ([Ca2+]o), on the intracellular Na+ concentration ([Na+]i), in frog intact hearts using nuclear magnetic resonance spectroscopy, which allows for the measurement of [Na+]i in perfused, beating hearts. Decreases in [Ca2+]o yielded marked increases in [Na+]i. A similar effect was seen during inhibition of the Na+/K+ pump and was fully reversible. This sensitivity of [Na+]i to [Ca2+]o, previously observed using microelectrodes, supports a crucial physiological role for Na+/Ca2+ exchange in frog intact, beating hearts.
Powell
D
D
Department of Radiology, Charles A. Dana Research Institute, Beth Israel Hospital and Harvard Medical School, Boston, MA 02215.
Burstein
D
D
Fossel
E T
ET
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010477:Perfusion; D011188:Potassium / Q000494:pharmacology; D011892:Rana catesbeiana; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology*
D012964:Sodium; D011188:Potassium