Light- and electron-microscopic evidence of costoring of immunoreactive enkephalins and substance P in dorsal horn neurons of rat.
The topographical localization of substance P (SP) and methionine-enkephalin-octapeptide (Enk-8) was examined immunohistochemically in the surface layer of the dorsal horn of rat cervical spinal cord. Although a few neurons were immunoreactive for Enk-8 in the intact animals, after an intracisternal administration of colchicine, immunoreactive Enk-8 neurons were numerous, and half of them indicated immunoreactivity also for SP. Some immunoreactive SP neurons appeared to show no immunoreactivity for Enk-8. Immuno-reactive nerve fibers, on the other hand, were numerous, and many of them contained both peptides. Electron-microscopic examination of the nerve fibers in tissue prepared by a freeze-drying procedure and stained by a postembedding procedure, revealed the costoring of both peptides in the same cored vesicles. The physiological significance of this costoring is discussed.
Katoh
S
S
Department of Anatomy, School of Medicine, University of Tokushima, Japan.
Hisano
S
S
Kawano
H
H
Kagotani
Y
Y
Daikoku
S
S
D000818:Animals; D003078:Colchicine / Q000494:pharmacology; D004745:Enkephalins / Q000032:analysis*; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000032:analysis* / Q000187:drug effects / Q000648:ultrastructure; D013373:Substance P / Q000032:analysis*
D004745:Enkephalins; D013373:Substance P; D003078:Colchicine