Fig. 4.

Lack of K⁺-dependent water permeability in M1, M23, and Mz-expressing oocytes. Oocytes expressing the three different isoforms were voltage-clamped to −50 mV to avoid K⁺-dependent changes in membrane potential and exposed to test solution containing the standard 2 mM K⁺ (+6 mM Ch⁺) in which the L _p was determined. Subsequently the same oocyte was exposed to a test solution containing 8 mM K⁺ in which the L _p was determined. The data are presented as the L _p obtained in 8 mM K⁺ relative to that obtained in 2 mM K⁺ (n = 4 of each)