title: Serotonin-positive fibers within the spinal motor nucleus of the newborn rat, with special reference to co-localization of substance P.
abstract: Developmental changes of serotonin-positive fibers with special reference to co-localization with substance P was examined immunohistochemically in the ventral horn of rat lumbar spinal cord. Only about 20% of serotonin-positive fibers co-labelled with substance P on postnatal day (P) 0. The ratio of co-localization gradually increased, and reached the adult value by P28 (60-70%). Enkephalin-positive fibers were not co-localized with serotonin at any age examined. Although the densities of serotonin, substance P and enkephalin per unit area of the ventral horn gradually increased with development up to P28, the density of serotonin in the adult was decreased compared to P28 animals.
authors.affiliation: Department of Physiology, University of Tsukuba, Ibaraki, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ozaki
authors.forename: N
authors.initials: N
authors.lastname: Kudo
authors.forename: N
authors.initials: N
authors.lastname: Okado
mesh_terms: D000344:Afferent Pathways / Q000737:chemistry; D000818:Animals; D000831:Animals, Newborn / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism; D005260:Female; D051381:Rats; D011919:Rats, Inbred Strains / Q000254:growth & development / Q000378:metabolism; D012701:Serotonin / Q000032:analysis*; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000737:chemistry / Q000254:growth & development; D013373:Substance P / Q000032:analysis*
chemical_list: D012701:Serotonin; D013373:Substance P