Neuropharmacology of the dorsal root entry zone.

The finding of a number of peptides in the central nervous system and the discovery of the endogenous opiates represent major recent advances in the understanding of neural transmission. A number of these neuropeptides are found in the dorsal root entry zone and may play a role in pain. An analysis of changes in distribution of substance P, methionine-enkephalin, and somatostatin after simulated nerve root avulsion injury suggested a possible mechanism for deafferentation pain. A review of the localizations and actions of these peptides in the dorsal root entry zone is included.