Developmental maturation of ionotropic glutamate receptor subunits in rat vestibular nuclear neurons responsive to vertical linear acceleration

Suk King Lai, Chun Hong Lai, Yiu Chung Tse, Kin Lam YUNG, Daisy K.Y. Shum, Ying Shing Chan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

We investigated the maturation profile of subunits of ionotropic glutamate receptors in vestibular nuclear neurons that were activated by sinusoidal linear acceleration along the vertical plane. The otolithic origin of Fos expression in these neurons was confirmed as a marker of functional activation when labyrinthectomized and/or stationary control rats contrasted by showing sporadically scattered Fos-labeled neurons in the vestibular nuclei. By double immunohistochemistry for Fos and one of the receptor subunits, otolith-related neurons that expressed either α-amino-3-hydroxy-5-methyl-4-isoxazole- propionate or N-methyl-d-aspartate subunits were first identified in the medial vestibular nucleus, spinal vestibular nucleus and Group x by postnatal day (P)7, and in the lateral vestibular nucleus and Group y by P9. No double-labeled neurons were found in the superior vestibular nucleus. Within each vestibular subnucleus, these double-labeled neurons constituted ∼90% of the total Fos-labeled neurons. The percentage of Fos-labeled neurons expressing the GluR1 or NR2A subunit showed developmental invariance in all subnuclei. For Fos-labeled neurons expressing the NR1 subunit, similar invariance was observed except that, in Group y, these neurons decreased from P14 onwards. For Fos-labeled neurons expressing the GluR2, GluR2/3, GluR4 or NR2B subunit, a significant decrease was found by the adult stage. In particular, those expressing the GluR4 subunit showed a two- to threefold decrease in the medial vestibular nucleus, spinal vestibular nucleus and Group y. Also, those expressing the NR2B subunit showed a twofold decrease in Group y. Taken together, the postsynaptic expression of ionotropic glutamate receptor subunits in different vestibular subnuclei suggests that glutamatergic transmission within subregions plays differential developmental roles in the coding of gravity-related vertical spatial information.

Original languageEnglish
Pages (from-to)2157-2172
Number of pages16
JournalEuropean Journal of Neuroscience
Volume28
Issue number11
DOIs
Publication statusPublished - Dec 2008

Scopus Subject Areas

  • Neuroscience(all)

User-Defined Keywords

  • c-fos
  • Glutamate receptor
  • Gravity
  • Postnatal

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