Electrophysiology of Madin-Darby canine kidney II (MDCKII), OK, and LLCPK cells. Comparison of transepithelial resistance (TER; A), permeability ratio (PNa/PCl; B), and absolute permeability of sodium (Na+; C) and chloride (Cl−; D) across confluent monolayers of MDCKII cells, OK cells, and LLCPK cells; n ≥ 4 per cell type. Grey dashed line represents the ratio of sodium to chloride permeability (PNa/PCl) ratio of 1. Data are presented as means ± SE.