I was recently looking at an I/V plot for K+ current in a neuron, and
the plot was a straight line with an x-intercept (zero current) at
about -45mV. I was told the K+ reversal potential is about -80mV, so
I assumed the voltage-gated K+ channel stopped current flow at that
point, but I don't know enough about the properties of the K+ channel
to be sure about that. The K+ concentration inside and outside the
cell was what a normal neuron would have.
Was I wrong about the reason the K+ current stopped? It sounds like
there's a better reason, but I don't know it...