title: Enkephalin and capsaicin-resistant substance P-like immunoreactivities in intra-ocular grafts of different fetal spinal cord areas.
abstract: Fetal spinal cord tissue was grafted to the anterior chamber of the eye of adult rats in order to evaluate survival and distribution of substance P- and enkephalin-immunoreactive neurons. Capsaicin treatment was used to evaluate any possible contribution of host iris-derived substance P fibres to the innervation of the grafts and to check for capsaicin sensitivity of graft substance P-positive systems. Substance P- and enkephalin-immunoreactive nerve fibres were present in grafts of half-transverse segments of the spinal cord and were clearly co-distributed throughout the grafts. Areas with a high density of substance P- and enkephalin-positive fibres resembling substantia gelatinosa were seen. Grafts of the dorsal horn alone had a moderate to high density of substance P- and enkephalin-positive fibres, while ventral horn grafts contained a low amount of such fibres. Capsaicin eliminated the substance P innervation of the host iris and the dorsal root ganglion-derived substance P innervation of the host spinal cord, while sparing the intrinsic substance P innervation of both host spinal cord and spinal cord grafts. These experiments show that intra-ocular grafts of defined spinal cord areas express relatively organotypic amounts of substance P- and enkephalin-positive nerve fibres, and thus emphasize the importance of intrinsic genetic determinants for spinal cord development.
mesh_terms: D000818:Animals; D000867:Anterior Chamber; D002211:Capsaicin / Q000494:pharmacology*; D004745:Enkephalins / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D006085:Graft Survival / Q000187:drug effects; D007498:Iris / Q000294:innervation; D008297:Male; D009412:Nerve Fibers / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism* / Q000637:transplantation; D013373:Substance P / Q000378:metabolism*
chemical_list: D004745:Enkephalins; D013373:Substance P; D002211:Capsaicin