Figure 2.

Theoretical current–voltage relations for open Na and K channels. (A) The solid curves are from Eqs. 3a (the Na curve is the almost horizontal line, just negative to zero), and the dashed curves from Eqs. 3b. For both sets of curves, I_Na = −I_K at −80 mV; i.e., the resting potential is −80 mV. (B) Approximately linear current–voltage relations, generated from Eqs. 8. These relations are most similar to the experimentally observed curves, but the model works well when any of the three pairs of current–voltage relations are used, as described in the text.