Axoplasmic asymmetry at the node of Ranvier.

The previously described unilateral condensation of axoplasmic organelles at the node of Ranvier of large diameter fibres in spinal nerve roots has been confirmed in a single normal rabbit. The tendency for this phenomenon to occur on the proximal (neuronal) side of the node, as implied in previous studies, could not be supported by numerical analysis which failed to show statistical significance for any one distribution pattern. This absence of polarization may be related to the existence of both anterograde and retrograde traffic in large diameter fibres.