title: Expression of the glycinergic system during the course of embryonic development in the mouse spinal cord and its co-localization with GABA immunoreactivity.
abstract: To understand better the role of glycine and gamma-aminobutyric acid (GABA) in the mouse spinal cord during development, we previously described the ontogeny of GABA. Now, we present the ontogeny of glycine-immunoreactive (Gly-ir) somata and fibers, at brachial and lumbar levels, from embryonic day 11.5 (E11.5) to postnatal day 0 (P0). Spinal Gly-ir somata appeared at E12.5 in the ventral horn, with a higher density at the brachial level. They were intermingled with numerous Gly-ir fibers reaching the border of the marginal zone. By E13.5, at the brachial level, the number of Gly-ir perikarya sharply increased throughout the whole ventral horn, whereas the density of fibers declined in the marginal zone. In the dorsal horn, the first Gly-ir somata were then detected. From E13.5 to E16.5, at the brachial level, the density of Gly-ir cells remained stable in the ventral horn, and after E16.5 it decreased to reach a plateau. In the dorsal horn, the density of Gly-ir cells increased, and after E16.5 it remained stable. At the lumbar level, maximum expression was reached at E16.5 in both the ventral and dorsal horn. Finally, the co-localization of glycine and GABA was analyzed, in the ventral motor area, at E13.5, E15.5, and E17.5. The results showed that, regardless of developmental stage studied, one-third of the stained somata co-expressed GABA and glycine. Our data show that the glycinergic system matures 1 day later than the GABAergic system and follows a parallel spatiotemporal evolution, leading to a larger population of glycine cells in the ventral horn.
authors.affiliation: Laboratoire de Neurobiologie des Réseaux, Université Bordeaux 1 et Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5816, Talence, France.
authors.forename: Anne-Emilie
authors.initials: AE
authors.lastname: Allain
authors.forename: Alexia
authors.initials: A
authors.lastname: Baïri
authors.forename: Pierre
authors.initials: P
authors.lastname: Meyrand
authors.forename: Pascal
authors.initials: P
authors.lastname: Branchereau
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D047108:Embryonic Development; D005998:Glycine / Q000096:biosynthesis*; D007150:Immunohistochemistry; D051379:Mice; D018613:Microscopy, Confocal; D009474:Neurons / Q000378:metabolism; D013116:Spinal Cord / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D005680:gamma-Aminobutyric Acid; D005998:Glycine