Differences in intramembranous particle distribution in the paranodal axolemma are not associated with functional differences of dorsal and ventral roots.

Freeze-fracture methods were used to study intramembranous particles, which are believed to represent ectopic sodium channels in the paranodal axolemma, and their possible association with differences in action potential electrogenesis of maturing rat dorsal and ventral root fibers. Our results indicate that there is no significant association between paranodal axon membrane structure and the functional difference of dorsal and ventral root axons.