An established cell line from mouse kidney medullary thick ascending limb. II. Transepithelial electrophysiology

This study investigates the transepithelial electrophysiological properties of two mouse kidney medullary thick ascending limb cell lines developed in our laboratory. By using a modified Ussing chamber, the transepithelial voltage, transepithelial resistance, and short-circuit current of monolayer cultures were determined. Normal transport functions of the medullary thick ascending limb were not expressed in the cell lines. Instead, they exhibited electrogenic sodium absorption, which could be inhibited by the sodium channel blocker amiloride. Transplantation of the cell line M-mTAL-1C into allogeneic mice in diffusion chambers elicited reexpression of the medullary thick ascending limb transport phenotype, including development of a characteristic basal negative transepithelial voltage sensitive to the loop diuretic furosemide and to chloride removal. These results indicate that retention of renal tubule-specific transport properties is possible in long-term cell culture. However, their expression requires a special milieu not provided by current culture systems.