title: Neuronal map reveals the highly regionalized pattern of the juvenile central nervous system of the ascidian Ciona intestinalis.
abstract: BACKGROUND
  The dorsally located central nervous system (CNS) is an important hallmark of chordates. Among chordates, tunicate ascidians change their CNS remarkably by means of a metamorphosis from a highly regionalized larval CNS to an oval-shaped juvenile CNS without prominent morphological features. The neuronal organization of the CNS of ascidian tadpole larvae has been well described, but that in the CNS of postmetamorphosis juveniles has not been characterized well.
  
  
  RESULTS
  We investigated the number of neural cells, the number and position of differentiated neurons, and their axonal trajectories in the juvenile CNS of the ascidian Ciona intestinalis. The cell bodies of cholinergic, glutamatergic, and GABAergic/glycinergic neurons exhibited different localization patterns along the anterior-posterior axis in the juvenile CNS. Cholinergic neurons extended their axons toward the oral, atrial and body wall muscles and pharyngeal gill to regulate muscle contraction and ciliary movement.
  
  
  CONCLUSIONS
  Unlike its featureless shape, the juvenile CNS is highly patterned along the anterior-posterior axis. This patterning may be necessary for exerting multiple roles in the regulation of adult tissues distributed throughout the body. This basic information of the juvenile CNS of Ciona will allow in-depth studies of molecular mechanisms underlying the reconstruction of the CNS during ascidian metamorphosis.
authors.affiliation: Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Hozumi
authors.affiliation: Japan Science and Technology Agency, PRESTO, Honcho, Kawaguchi, Saitama, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Horie
authors.affiliation: Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sasakura
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000378:metabolism; D019521:Body Patterning; D002454:Cell Differentiation; D002490:Central Nervous System / Q000254:growth & development*; D059329:Cholinergic Neurons / Q000378:metabolism; D002938:Ciona intestinalis / Q000254:growth & development*; D018274:Electroporation; D059330:GABAergic Neurons / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry; D008027:Light; D008675:Metamorphosis, Biological; D009474:Neurons / Q000378:metabolism / Q000502:physiology
chemical_list: D005973:Glutamine
keywords: ascidian; juvenile; metamorphosis; neuron