Cardiac Action and Pacemaker Potentials based on the Hodgkin-Huxley Equations

SINCE the equations describing the nerve action potential were formulated by Hodgkin and Huxley1, the range of phenomena to which they have been shown to apply has been greatly extended. Huxley2has applied them to the influence of temperature on the propagated response and to the repetitive firing observed in low calcium concentrations. More recently, Fitzhugh3 has shown that the long action potentials induced by tetraethylammonium ions in squid nerve may also be reproduced.