[pjin]

A search on Wikipedia turned up this 1976 paper [1] (unfortunately, behind a paywall), which derived a memristor circuit emulating Hodgkin-Huxley dynamics, a good biophysical model of the membrane potential of a neuron. In particular, it can show the generation of action potentials.

The relevant part is on p. 210: "In particular, the potassium channel of the Hodgkin-Huxley model should be identified as a first-order time-invariant voltage-controlled memristive one-port and the sodium channel should be identified as a second-order time-invariant voltage-controlled memristive one-port."

[1] http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1454361...