Background and Objectives : Fos is a protein product of proto-oncogene c-fos, which is induced
by various kinds of stimulation such as noxious, physiologic and electrical stimulations. In the
vestibular system, there have been several evidences that c-fos was expressed in the brainstem
vestibular nuclei during vestibular compensation following unilateral labyrinthectomy(ULX). In this
study, the author evaluated the effect of deafferented sensory inputs on the c-fos mRNA
expression in the medial vestibular nucleus of unilaterally labyrinthectomized rats.
Materials and Methods : Animals in the experiental group immediately after ULX, whereas the
experimental groupⅡ did not receive any procedure after ULX. Expression of c-fos mRNA was
demonstrated by in situ hybridization technique. All animals were sacrificed at 1,3,6,9,24,48 hours
after ULX and frozen sectionedtissures of brainstem were used in situ hybridization.
Results : Three hours after ULX, the expression of c-fos mRNA was increased in the dorsal
portion of medial vestibular nucleus(dMVN) in both groups and after 6 hours of ULX, it was
markedly reduced. In group I (deafferented), however, asymmetric expression was observed in 24
hours after the operation. In group Ⅱ, the increased expression of c-fos mRNA in the ipsilateral
dMVN continued until 9 hours after the decreased.
Conclusion : These findings suggest that vision and prprioception influenced the expression of
c-fos mRNA in the brainstem medial vestibular nucleus after ULX, and corrected the asymmetric
expression between the healthy and lesioned nuclei earlier than the deafferented group.
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