J Korean Bal Soc.  2006 Dec;5(2):213-223.

Role of the Peripheral Vestibular System on Neuroplasticity Induced by Hypergravity Stimulation

• Lee JH
• Lee GW
• Park HS
• Lee JH
• Choi DO
• Choi MA
• Park BR

Abstract

BACKGROUND AND OBJECTIVES: Altered environmental gravity, including both hypo- and hypergravity, may result in space adaptation syndrome. To explore the characteristics of this adaptive plasticity, the expression of immediate early gene c-fos mRNA in the vestibular system following an exposure to hypergravity stimulus was determined in rats. MATERIALS AND METHOD: The animals were subjected to 2 G force (two-fold earth's gravity) stimulus for 3 hours, and were examined at post-stimulus hours 0, 2, 6, 12, and 24. Real time reverse transcription-polymerase chain reaction (RT-PCR) was adopted to analyze temporal changes in the expression of c-fos mRNA.
RESULTS
The hypergravity stimulation produced the expression of c-fos mRNA in the vestibular ganglion, medial vestibular nucleus, inferior vestibular nucleus, hippocampus, vestibulocerebellum, and vestibular cortex. The peak expression occurred at hour 6 in the animals hypergravity-stimulated for 3 hours. Bilateral labyrinthectomy significantly attenuated the degree of up-regulation in c-fos mRNA expression. MK-801, an NMDA receptor antagonist, also significantly attenuated the degree of up-regulation in c-fos mRNA expression.
CONCLUSION
These results indicate that the adaptive neuroplasticity in response to an altered gravity occurs in the vestibular-related organs in the central nervous system, in which peripheral vestibular receptors and NMDA receptors play an important role.

Keyword

Hypergravity; Neuronal plasticity; Vestibule; c-fos gene

MeSH Terms

Animals
Central Nervous System
Dizocilpine Maleate
Ganglion Cysts
Genes, fos
Gravitation
Hippocampus
Hypergravity*
N-Methylaspartate
Neuronal Plasticity*
Plastics
Rats
Receptors, N-Methyl-D-Aspartate
RNA, Messenger
Space Motion Sickness
Up-Regulation
Vestibular Nuclei
Dizocilpine Maleate
N-Methylaspartate
Plastics
RNA, Messenger
Receptors, N-Methyl-D-Aspartate