title: Preferential localization of neural cell recognition molecule NB-2 in developing glutamatergic neurons in the rat auditory brainstem.
abstract: NB-2 is a neuronal cell recognition molecule that is preferentially expressed in auditory pathways. Mice deficient in the NB-2 gene exhibit aberrant responses to acoustic stimuli. Here we examined the expression and localization of NB-2 in the auditory brainstem during development in the rat. NB-2 was strongly expressed in the ventral cochlear nucleus (VCN), ventral acoustic stria, lateral and medial superior olivary complex (SOC), superior paraolivary nucleus, medial nucleus of the trapezoid body (MNTB), ventrolateral lemniscus, and central nucleus of the inferior colliculus (CIC). In the VCN and CIC, NB-2 was expressed in the regions that are known to respond to high frequencies. In situ hybridization combined with immunohistochemistry suggested that NB-2 is expressed only in neurons. NB-2 was colocalized with glutamatergic elements in the neuropil and the calyces of Held but not with glycinergic or GABAergic elements. NB-2 expression in the SOC was first detected at embryonic day (E)19, reached a maximum level at postnatal day (P)7, and declined thereafter. Immunolabeling with VGLUT1 and VGLUT2, markers for mature and premature glutamatergic synapses, respectively, in combination with NB-2 immunolabeling revealed that NB-2 is expressed at glutamatergic synapses. Collectively, our findings suggest that NB-2 plays a key role in maturation of glutamatergic synapses in the brainstem during the final stages of auditory development.
authors.affiliation: Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Toyoshima
authors.forename: Kunie
authors.initials: K
authors.lastname: Sakurai
authors.forename: Kuniko
authors.initials: K
authors.lastname: Shimazaki
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takeda
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakamoto
authors.forename: Shou
authors.initials: S
authors.lastname: Serizawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shimoda
authors.forename: Kazutada
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D015153:Blotting, Western; D001933:Brain Stem / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D058966:Contactins; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000378:metabolism; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; C104187:Cntn5 protein, rat; D058966:Contactins; C493475:Slc17a6 protein, rat; C493466:Slc17a7 protein, rat; D050598:Vesicular Glutamate Transport Protein 1; D050599:Vesicular Glutamate Transport Protein 2; D018698:Glutamic Acid; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1