Fig. 7.

⁸⁶Rb⁺ influx as a function of ion concentration for the 6-parameter model of the NKCC2 cotransporter for the 3 isoforms reported in Plata et al. (13). A: Na⁺ uptake. B: Cl⁻ uptake. C: K⁺ uptake. Blue curves were obtained by computing optimal parameters by allowing the off-binding rates to vary and keeping fixed the translocation rates to the parameters reported by Benjamin and Johnson (2) for the LLC-PK₁ cells. For comparison, the results obtained by evaluating the parameters reported by Benjamin and Johnson (2) in the 6-parameter model are included.