Title: Effect of Anesthetics on Action Potential Propagation.
Abstract: Local anesthesia has been attributed to the specific
interaction of local anesthetics with (sodium) channel proteins, while the
action of general anesthetics still remains unclear. However, already at
the beginning of 20th century Meyer and Overton independently found that
the critical anesthetic dose of anesthetics, regardless of their types, is
linearly proportional to their solubility in olive oil. Heimburg and
Jackson proposed that the action potential is a density pulse (soliton)
propagating in biological membranes and made a thermodynamic extension of
the Meyer-Overton rule, incorporating the effects of melting point
depression that originates from van't Hoff's law.
In this work, experiments were done on nerves to study the effect of local
anesthetic lidocaine on compound action potential and action potential
from a single neuron. The experimental data were then compared with the
simulation results by solving the soliton equations in 1D cylindrical
membrane with lidocaine inside the system. Anesthetics move the chain
melting transition temperature of membranes far away from the
physiological temperature, thus it requires a higher free energy to induce
the phase transition, resulting in a higher stimulation voltage to reach
the maximum amplitude of the action potential. At the same time, the
velocity of action potential propagation is slightly slowed down by
lidocaine.