Experimental anatomical considerations of the dorsal root entry zone lesions for pain relief.

Dorsal root entry zone (DREZ) lesions were made in the cervical dorsal horn in cat and monkey. Terminal degeneration was observed in the lateral cervical nucleus in cat and contralateral VPL in monkey by Fink-Heimer stain. WGA-HRP was injected in the cervical dorsal horn of cat and retrograde labelled cells were observed mainly in the raphe nucleus, parabrachial nucleus, locus coeruleus, Kölliker-Fuse nucleus, Eddinger-Westphal nucleus, and hypothalamic area, indicating that these descending fiber systems are involved by the DREZ lesion. The functional role of these fibers in regard to deafferentation pain relief seems now to be open to discussion.