Expression of glycine receptors and gephyrin in rat medial vestibular nuclei and flocculi following unilateral labyrinthectomy

Abstract

The medial vestibular nucleus (MVN) and the cerebellar flocculus have been known to be the key areas involved in vestibular compensation (VC) following unilateral labyrinthectomy (UL). In this study, we examined the role of gephyrin and glycine receptor (GlyR) in VC using Sprague-Dawley rats, in an aim to gain deeper insight into the mechanisms responsible for VC. The expression of the α1 and β subunits of GlyR and gephyrin was immunohistochemically localized in rat MVN and flocculi. The mRNA and protein expression of GlyR (α1 and β subunits) and gephyrin was quantitatively determined by RT-qPCR and western blot analysis at 8 h, and at 1, 3 and 7 days following UL. It was found that in the ipsilateral MVN, the mRNA and protein expression of the β subunit of GlyR was significantly increased in comparison to the sham-operated (P<0.01) rats, and in comparison to the contralateral side (P<0.01) at 8 h following UL. In the ipsilateral flocculi, GlyR β protein expression was significantly elevated (P<0.01 for all), as compared to the sham-operated rats at 8 h, and at 1 and 3 days and to the contralateral side 8 h, 1 and 3 days following UL. No significant differences were observed in the mRNA and protein expression of GlyR α1 and gephyrin in the MVN or flocculi between the two sides (ipsilateral and contralateral) in the UL group, and between the sham-operated group and the UL group at any time point. The findings of our study thus suggest that GlyR plays a major role in the recovery of the resting discharge of the deafferented MVN neurons in the central vestibular system.

mGluR1/IP3/ERK signaling pathway regulates vestibular compensation in ON UBCs of the cerebellar flocculus

“…UL 13 , 14 was performed on the right side of male SD rats aged 8–10 weeks under anesthesia. The operator made an incision, opened the tympanic bulla wall, removed the tympanic bulla, malleus, and incus, and destroyed the vestibule with absolute alcohol.…”

“…Blinded assessors scored the static symptoms of vestibular imbalance, 8 , 13 , 14 , 16 , 17 including spontaneous nystagmus, head tilt, postural asymmetry, and tall‐hanging test, presented in behavioral tests. Spontaneous nystagmus was recorded by a video eye‐tracking system and scored on a scale of 6~10 points in terms of bpm.…”

Multisensory Exercise Improves Balance in People with Balance Disorders: A Systematic Review

“…Our analysis indicated that the optimal intervention time might be less than 6 weeks and multisensory exercises beyond 6 weeks are not necessary. And animal studies showed the time taken for vestibular compensation was no more than 7 days [70,71] . The intervention time should suffice to modulate central nervous plasticity.…”

Preferential pruning of inhibitory synapses by microglia contributes to alteration of the balance between excitatory and inhibitory synapses in the hippocampus in temporal lobe epilepsy

“…Despite their small number, interneurons are essential for the homeostasis of neural circuits in the brain, where they attach to specific excitatory inputs and provide feedforward and feedback inhibition to pyramidal neurons, maintaining homeostasis of neural activity in the brain 21,22 . Gephyrin, an inhibitory postsynaptic protein, is widely distributed in the CA1, CA3, and DG of TLE rats 23 . In addition, the onset of seizures reduced gephyrin expression in the hippocampus and adjacent neocortex 24 .…”

“… 21 , 22 Gephyrin, an inhibitory postsynaptic protein, is widely distributed in the CA1, CA3, and DG of TLE rats. 23 In addition, the onset of seizures reduced gephyrin expression in the hippocampus and adjacent neocortex. 24 Furthermore, gephyrin significantly downregulated in the human temporal neocortex in patients with mesial temporal lobe epilepsy (mTLE).…”