ELECTRICAL-PROPERTIES OF MAMMALIAN LENS EPITHELIAL GAP JUNCTION CHANNELS

Purpose. To establish an ''electrical fingerprint'' for the gap juncti on channels between mammalian lens epithelial cells. Methods. The doub le whole cell patch clamp technique was applied to isolated cell pairs obtained from mouse lens epithelium and a continuous cell line of len s epithelial cells derived from the sheep lens (SLE 2.1). Results. The junctional conductance in mouse lens epithelial cells and in cultured SLE 2.1 cells was found to be moderately voltage dependent. SLE 2.1 c ells were analyzed in more detail. The voltage dependence could be des cribed by a Boltzmann distribution with V-o = +/- 63.1 mV and G(min) = 0.34. In cell pairs that exhibited spontaneously low junctional condu ctance, single channel events could be distinguished. Single gap junct ion channel currents had a linear current-voltage relationship. A freq uency histogram of single channel conductances from eight cell pairs h ad three major peaks of 35, 60, and 97 pS. Conclusion. The electrical properties of gap junction channels between mammalian lens epithelial cells were virtually identical to those previously reported for transf ected cell lines expressing connexin43. The authors' physiological dat a are therefore in agreement with molecular studies that have identifi ed connexin43 as the major connexin of lens epithelial cells.