Organization of the axolemma in amyelinated axons: a cytochemical study indy/dydystrophic mice

Abstract

In normal myelinated fibers there are structural differences between the axon membrane at nodes of Ranvier and in the internodes beneath the myelin sheath. The results of a cytochemical study [using EM] on the axon membrane in amyelinated axons in dy/dy dystrophic mice, in which myelination is focally absent owing to a genetic defect, were reported. The amyelinated axon membrane, known to be capable of sustaining continuous impulse conduction, was structurally different from normal nodal membrane. Comparison of the cytochemical results with physiological and pharmacological data suggested that the amyelinated dystrophic axon membrane may exhibit a lower Na+ channel density than normal nodal membrane.