Membrane and junctional properties of dissociated frog lens epithelial cells

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Abstract
Individual cells and cell pairs were isolated from frog lens epithelium. Individual cells were whole cell voltage clamped and the current-voltage relationship was determined. The cells had a mean resting voltage of −54.3 mV and a mean input resistance of 1.4 GΩ. The current-voltage relationship was linear near the cell resting voltage, but showed decreased resistance with large depolarization or hyperpolarization. Junctional currents between pairs of cells were recorded using the dual whole cell voltage-clamp technique. The corrected junctional resistance was 15.5 MΩ (64.5 nS). The junctional current-voltage relationship was linear. A combination of ATP and cAMP, in the electodes, stabilized junctional resistance. Currents recorded when uncoupling was nearly complete, showed evidence of single connexon gating events. A single-channel conductance of about 100 pS was prominent. Dye spread between isolated cell pairs was demonstrated using Lucifer Yellow CH in a whole cell configuration. Photodamage to the cells due to the dye was apparent. Dye loaded cells, in the presence of exciting light, showed decreased resting voltages, decreased input resistances and morphological changes. Glutathione (20mm) delayed this damage.