Fusion of renal epithelial cells: a model for studying cellular mechanisms of ion transport.

The investigation of epithelial ion transport at the cellular level by means of electrophysiological techniques is hampered by the small size of epithelial cells. Moreover, interpretation of experiments is complex due to poorly defined and highly variable paracellular leaks (shunt pathways). In search of a new experimental approach we developed a technique to isolate renal epithelial cells (diameter approximately equal to 10 micron) from diluting segments of the frog kidney and to fuse them to "giant" cells (diameter approximately equal to 100 micron). These cells generate membrane potentials of -54.1 +/- 1.6 mV (mean +/- SEM; n = 40). They are sensitive to the diuretic drugs furosemide and amiloride and to the K+- and Cl- -permeability blockers Ba2+ and anthracene-9-carboxylic acid. The experiments demonstrate membrane potential measurements in cells isolated from renal epithelium and fused to giant cells. The cells retain their specific membrane properties and could serve as a valuable experimental model in epithelial research.