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The Development of Vestibular Connections in Rat Embryos in MicrogravityExisting experimental embryological data suggests that the vestibular system initially develops in a very rigid and genetically controlled manner. Nevertheless, gravity appears to be a critical factor in the normal development of the vestibular system that monitors position with respect to gravity (saccule and utricle). In fact several studies have shown that prenatal exposure to microgravity causes temporary deficits in gravity-dependent righting behaviors, and prolonged exposure to hypergravity from conception to weaning causes permanent deficits in gravity-dependent righting behaviors. Data on hypergravity and microgravity exposure suggest some changes in the otolith formation during development, in particular the size although these changes may actually vary with the species involved. In adults exposed to microgravity there is a change in the synaptic density in the otic sensory epithelia suggesting that some adaptation may occur there. However, effects have also been reported in the brainstem. Several studies have shown synaptic changes in the lateral vestibular nucleus and in the nodulus of the cerebellum after neonatal exposure to hypergravity. We report here that synaptogenesis in the medial vestibular nucleus is retarded in developing rat embryos that were exposed to microgravity from gestation days 9 to 19.
Document ID
19990113177
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Bruce, Laura L.
(Creighton Univ. Omaha, NE United States)
Fritzsch, Bernd
(Creighton Univ. Omaha, NE United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1997
Publication Information
Publication: Journal of Gravitational Physiology
Volume: 4
Issue: 2
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NCC2-861
Distribution Limits
Public
Copyright
Other

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