Action of surface-active agents on axonal conduction

Abstract

Three cationic as well as two anionic and two nonionized surfactants were examined for their axonal conduction blocking tendencies. Appreciable and irreversible block was effected by the ionic surfactants. In order of decreasing effectiveness they were: dioctyl sodium sulfosuccinate (AOT), cetyltrimethylammonium bromide (CTMB), cetylpyridinium chloride (CPC), sodium lauryl sulfate (SLS), and cetyldimethylbenzylammonium chloride (CDMBC). Only modest conduction block was produced by the nonionized surfactants— polyoxyethylene sorbitan monolaurate (T20) and polyoxyethylene sorbitan mono-oleate (T80). The results support the thesis that there is a correlation between cytolytic activity of surfactants and the propensity to block axonal conduction. The results are also in agreement with a previously expressed speculation that CTMB (and presumably other cytolytic surfactants) exerts disruptive and dispersive actions on the molecular morphology of the various permeability barriers in a nerve trunk such as the frog sciatic.