Figure 9.

Absence of nucleotide does not alter the flux ratio exponent n'. The axon was internally dialyzed with nucleotide-free, 99 mM Na⁺ solution and held at 0 mV throughout. (A and B) Na⁺ and K⁺ composition of the superfusate. (C) ²²Na⁺ efflux and net membrane current. The inset amplifies the data for the period between 40 and 80 min, showing the lack of outward electrogenic pump current or associated increase of ²²Na⁺ efflux after addition of 10 mM K⁺ to the Na⁺-free external solution. A detailed description of the experiment is given in the text. Blue and red lines have the same meaning as in previous figures.