  We suggest that the propagation of the action potential is driven by a
pressure pulse propagating in the axoplasm along the axon length. The pressure
pulse mechanically activates Na ion channels embedded in the axon membrane.
This activation initiates the development of a local membrane voltage spike, as
in the Hodgkin-Huxley model of the action potential. Extracellular Ca ions
influxing during the voltage spike trigger a mechanism that amplifies the
pressure pulse and therefore prevents its viscous decay. The model is able to
explain a number of phenomena that are unexplained within the Hodgkin-Huxley
framework: the Meyer-Overton rule for the effectiveness of anesthetics, as well
as various mechanical, optical and thermodynamic phenomena accompanying the
action potential. The model correctly predicts the velocity of propagation of
the nerve impulse, including its dependence on axon diameter, degree of
myelination and temperature.
