title: Conditional rhythmicity of ventral spinal interneurons defined by expression of the Hb9 homeodomain protein.
abstract: The properties of mammalian spinal interneurons that underlie rhythmic locomotor networks remain poorly described. Using postnatal transgenic mice in which expression of green fluorescent protein is driven by the promoter for the homeodomain transcription factor Hb9, as well as Hb9-lacZ knock-in mice, we describe a novel population of glutamatergic interneurons located adjacent to the ventral commissure from cervical to midlumbar spinal cord levels. Hb9+ interneurons exhibit strong postinhibitory rebound and demonstrate pronounced membrane potential oscillations in response to chemical stimuli that induce locomotor activity. These data provide a molecular and physiological delineation of a small population of ventral spinal interneurons that exhibit homogeneous electrophysiological features, the properties of which suggest that they are candidate locomotor rhythm-generating interneurons.
authors.affiliation: Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia, B3H 1X5, Canada.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Wilson
authors.forename: Robert
authors.initials: R
authors.lastname: Hartley
authors.forename: David J
authors.initials: DJ
authors.lastname: Maxwell
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Todd
authors.forename: Ivo
authors.initials: I
authors.lastname: Lieberam
authors.forename: Julia A
authors.initials: JA
authors.lastname: Kaltschmidt
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jessell
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brownstone
mesh_terms: D000818:Animals; D002417:Cattle; D004594:Electrophysiology; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000235:genetics; D013006:Growth Hormone / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007395:Interneurons / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D012326:RNA Splicing; D011995:Recombination, Genetic; D013116:Spinal Cord / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics*; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors; C084059:Hb9 protein, mouse; D049452:Green Fluorescent Proteins; D013006:Growth Hormone; D001616:beta-Galactosidase