Membrane differentiation in rat dorsal root ganglia and possible consequences for back pain.

The ferric ion-ferrocyanide staining procedure (Quick and Waxman, J. Neurol. Sci., 31 (1977) 1-11), believed to label selectively membrane regions with high sodium-channel content and hence elevated electrical excitability, was used to stain lower lumbar dorsal root ganglion (DRG) neurons in adult rats. In many such cells, including both large type A neurons and small type B neurons, the initial segment of the stem axon and a variable portion of the adjacent soma surface stained heavily. It is suggested that this membrane specialization represents a zone of elevated excitability which may contribute to ectopic impulse generation in DRGs.