THE IONIC BASIS OF ELECTRICAL ACTIVITY IN NERVE AND MUSCLE

作者：Alan Lloyd Hodgkin · 发表于：Biological reviews/Biological reviews of the Cambridge Philosophical Society · 年份：1951 · DOI：10.1111/j.1469-185x.1951.tb01204.x · 被引用次数：963 · 研究领域：Ion channel regulation and function、Electrochemical Analysis and Applications、Neuroscience and Neural Engineering

SUMMARY Four methods of determining the potential difference across the surface membrane of living cells are described. In a wide range of excitable tissues the resting membrane potential is of the order of 50–100 mV. and the action potential of the order of 80–130 mV. At the height of activity the potential difference across the membrane is reversed by 30–50 mV. The potassium concentration inside most excitable cells is 20–50 times greater than that in the external medium; sodium is 3–15 times more concentrated outside than it is inside, while chloride is 5–50 times more concentrated outside than inside. Isolated fibres lose potassium and gain sodium and chloride ions. Potassium appears to exist as a free ion inside nerve and muscle fibres. The nature of the organic anions which balance the high concentration of potassium inside excitable cells is still largely unknown. In certain cases amino‐acids such as aspartic acid are present in high concentrations. The resting membrane behaves as though it were moderately permeable to K+ and Cl‐ but sparingly permeable to Na+. The absolute magnitude of the resting potential is similar to that calculated from the potassium concentrations if allowance is made for the contributions of chloride and other ions. Movements of K+ and Cl‐ as determined by radioactive tracers or by chemical methods agree with a quantitative formulation of this hypothesis. It is necessary to suppose that sodium is continuously pumped out of excitable cells by a ...