The Plastic Changes In Glycinergic Receptors And Gephyrin Expression In The Medial Vestibular Nucleus And Flocculus In Different Stages Following Unilateral Labyrinthectomy In The Rat

Part I The plastic changes in glycinergic receptors and gephyrin expression in the medial vestibular nucleus in different stages following unilateral labyrinthectomy in the ratObjective To observe the localization of al and β of GLYR and Gephyrin in the normal adult rats and expression of al and β of GLYR and Gephyrin in the medial vestibular nucleus(MVN) following unilateral labyrinthectomy (UL).Methods99SD rats were randomly divided into three groups.48animals received unilateral labyrinthectomy while the others48maintained labyrinthine well. In another group of3rats, animals underwent neither a UL nor sham operation was used for immunohistochemical study. The RT-PCR and western blot were used to observed the change ofal and βof GLYR and Gephyrin post-unilateral labyrinthectomy.Results In adult rats, a strong immunoreactivity for al and β subunits of GLYR and gephyrin was present in all the MVNn. β subunit of GLYR was increased in lesioned side MVN after unilateral labyrinthectomy. The8h post-UL was increased, while ld,3d and7d post-UL were same as control group. There are no change between contralateral and control group. al subunit of GLYR and Gephyrin were no changes.Conclusion Increase of β subunit of GLYR contributed to the rebalancing of spontaneous resting activity between the ipsilateral and contralateral MVNs. It is suggested that such changes in the activities of the MVNs may be important to the early vestibular compensation process. Part II The plastic changes in glycinergic receptors and gephyrin expression in the flocculus in different stages following unilateral labyrinthectomy in the ratObjective To observe the localization of al and P of GLYR and Gephyrin in the normal adult rats and expression of al and β of GLYR and Gephyrin in the flocculus following unilateral labyrinthectomy (UL).Methods99SD rats were randomly divided into three groups.48animals received unilateral labyrinthectomy while the others48maintained labyrinthine well. In another group of3rats, animals underwent neither a UL nor sham operation was used for immunohistochemical study. The RT-PCR and western blot were used to observed the change ofal and Pof GLYR and Gephyrin post-unilateral labyrinthectomy.Results In normal rats’s flocculus, the al and β subunits of GLYR and gephyrin were moderate to strong staining in the between granule cell layer and the Purkinje cell layer, especially in the Purkinje cell. The β subunit of GLYR was increased in lesioned side flocculus after unilateral labyrinthectomy. The8h, ld and3d post-UL were increased. Then it was same to control group, In the contralateral flocculus, no changes in protein expression were observed. al subunit of GLYR and Gephyrin were no changes.Conclusion The increase in β subunit of GLYR in the ipsilateral flocculus may have had the effect or reducing Purkinje cell inhibition of ipsilateral VNC neurons, thereby contributing to the rebalancing of spontaneous resting activity between the ipsilateral and contralateral VNCs. It is suggested that such changes in the activities of the floccular-VNC pathways may be responsible for the vestibular compensation process.