title: Developmental localization of calcitonin gene-related peptide in dorsal sensory axons and ventral motor neurons of mouse cervical spinal cord.
abstract: Calcitonin gene-related peptide (CGRP) is a 37-amino-acid neuropeptide, synthesized by alternative splicing of calcitonin gene mRNA. CGRP is characteristically distributed in the nervous system, and its function varies depending on where it is expressed. To reveal developmental formation of the CGRP network and its function in neuronal maturation, we examined the immunohistochemical localization of CGRP in the developing mouse cervical spinal cord and dorsal root ganglion. CGRP immunolabeling (IL) was first detected in motor neurons on E13, and in ascending axons of the posterior funiculus and DRG neurons on E14. CGRP-positive sensory axon fibers entered Laminae I and II on E16, and Laminae I through IV on E18. The intensity of the CGRP-IL gradually increased in both ventral and dorsal horns during embryonic development, but markedly decreased in the ventral horn after birth. These results suggest that CGRP is expressed several days after neuronal settling and entry of sensory fibers, and that the CGRP network is formed in chronological and sequential order. Furthermore, because CGRP is markedly expressed in motor neurons when axons are vastly extending and innervating targets, CGRP may also be involved in axonal elongation and synapse formation during normal development.
authors.affiliation: Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 9030215, Japan.
authors.forename: Jeongtae
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 9030215, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Sunagawa
authors.affiliation: Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 9030215, Japan.
authors.forename: Shiori
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Department of Veterinary Anatomy, College of Veterinary Medicine, Jeju National University, Jeju 690-756, South Korea.
authors.forename: Taekyun
authors.initials: T
authors.lastname: Shin
authors.affiliation: Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, Uehara 207, Nishihara, Okinawa 9030215, Japan. Electronic address: takachan@med.u-ryukyu.ac.jp.
authors.forename: Chitoshi
authors.initials: C
authors.lastname: Takayama
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D009046:Motor Neurons / Q000378:metabolism*; D020671:Posterior Horn Cells / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000378:metabolism*; D013116:Spinal Cord / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D015740:Calcitonin Gene-Related Peptide
keywords: Calcitonin gene-related peptide; Dorsal horn; Dorsal root ganglion; Embryonic development; Spinal cord; Ventral horn