The membrane potential and permeabilities of the L cell membrane to Na, K and chloride

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Abstract
1. The chloride content and fluxes, and the membrane potential of L cells have been measured.2. L cells contain chloride, 70 m‐mole/l. intracellular water and have a flux of 5·5 p‐mole/cm2 sec.3. The membrane potential is −15 mV.K‐free Krebs causes an increase in Em and replacing chloride with sulphate causes a temporary reduction in Em.4. These values for Em and chloride, and previously obtained values for Na and K fluxes and contents were used to calculate the permeabilities of the various ions using the Goldman constant field theory. This gave permeabilities of 6·3, 4·2 and 51 × 10−9 cm/sec for K, Na and chloride respectively, a ratio of 1:0·67:8·10.5. It is concluded that these cells have a low membrane potential because the PK is some 100 times lower than in skeletal muscle, therefore leading to a PK of the same order as PNa.