title: Maturation of glutamatergic transmission in the vestibulo-olivary pathway impacts on the registration of head rotational signals in the brainstem of rats.
abstract: The recognition of head orientation in the adult involves multi-level integration of inputs within the central vestibular circuitry. How the different inputs are recruited during postnatal development remains unclear. We hypothesize that glutamatergic transmission at the vestibular nucleus contributes to developmental registration of head orientations along the vestibulo-olivary pathway. To investigate the maturation profile by which head rotational signals are registered in the brainstem, we used sinusoidal rotations on the orthogonal planes of the three pairs of semicircular canals. Fos expression was used as readout of neurons responsive to the rotational stimulus. Neurons in the vestibular nucleus and prepositus hypoglossal nucleus responded to all rotations as early as P4 and reached adult numbers by P21. In the reticular formation and inferior olive, neurons also responded to horizontal rotations as early as P4 but to vertical rotations not until P21 and P25, respectively. Neuronal subpopulations that distinguish between rotations activating the orthogonally oriented vertical canals were identifiable in the medial and spinal vestibular nuclei by P14 and in the inferior olivary subnuclei IOβ and IOK by P25. Neonatal perturbation of glutamate transmission in the vestibular nucleus was sufficient to derange formation of this distribution in the inferior olive. This is the first demonstration that developmental refinement of glutamatergic synapses in the central vestibular circuitry is essential for developmental registration of head rotational signals in the brainstem.
authors.affiliation: Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China.
authors.forename: Chun-Hong
authors.initials: CH
authors.lastname: Lai
authors.affiliation: Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China.|Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China.
authors.forename: Chun-Wai
authors.initials: CW
authors.lastname: Ma
authors.affiliation: Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China.|Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.|Department of Neurophysiology, Tokyo University, Tokyo, 113-0033, Japan.
authors.forename: Suk-King
authors.initials: SK
authors.lastname: Lai
authors.affiliation: Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China.|Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Han
authors.affiliation: Department of Orthopaedics and Traumatology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
authors.forename: Hoi-Man
authors.initials: HM
authors.lastname: Wong
authors.affiliation: Department of Orthopaedics and Traumatology, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
authors.forename: Kelvin Wai-Kwok
authors.initials: KW
authors.lastname: Yeung
authors.affiliation: Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China. shumdkhk@hku.hk.|Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China. shumdkhk@hku.hk.
authors.forename: Daisy Kwok-Yan
authors.initials: DK
authors.lastname: Shum
authors.affiliation: Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, People's Republic of China. yschan@hku.hk.|Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China. yschan@hku.hk.
authors.forename: Ying-Shing
authors.initials: YS
authors.lastname: Chan
mesh_terms: D000818:Animals; D016291:Dizocilpine Maleate / Q000008:administration & dosage; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage; D019706:Excitatory Postsynaptic Potentials; D005260:Female; D018698:Glutamic Acid / Q000502:physiology*; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009847:Olivary Nucleus / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012154:Reticular Formation / Q000378:metabolism / Q000502:physiology; D012399:Rotation; D012665:Semicircular Canals / Q000254:growth & development / Q000502:physiology*; D014726:Vestibular Nuclei / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000293:injuries
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016760:Proto-Oncogene Proteins c-fos; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D016291:Dizocilpine Maleate
keywords: Development; Fos expression; Glutamate receptor; Head rotation