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Abstract
The bioelectric potentials of rabbit lenses were studied before and after culture in a medium that simulated aqueous humor (KEI-4) and in medium in which varying concentrations of potassium, rubidium, or cesium were substituted for equivalent concentrations of sodium. The fiber-epithelial potential (inside to outside of lens) and fiber potential of rabbit lenses, as determined under physiologic conditions with glass electrodes, are -42 and -19 mv., respectively; the translens potential alone is -23 mv. when measured with a cotton wick electrode applied to the posterior surface of the lens. These potentials are maintained when lenses are cultured for 24 hours in KEI-4 medium at 37° C. The fiber-epithelial potential of lenses cultured in medium containing 50 mM potassium, rubidium, or cesium decreases from -42 to -28 mv. within one hour. It remains steady for 24 hours in the medium containing potassium, but declines slowly with time in medium containing rubidium or cesium. The fiber-epithelial potential of lenses cultured for 24 hours decreases with the concentration of potassium present in the medium; the potential decreases more with the concentration of rubidium or cesium, especially in the range of 0 to 10 mM. The translens potential falls linearly and about equally with the concentration of each of the cations. The fiber potential is not appreciably affected by 50 mM concentrations of rubidium or cesium and is only slightly depressed by the same concentration of potassium. Ouabain (10-5M) reduces the fiber-epithelial potential after a delay of several hours. No simple explanation appears adequate to explain all the observed effects on both the fiber and the fiber-epithelial potentials.