[Mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation].
OBJECTIVE
To study the mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation.


METHODS
Build up animal model of vestibular compensation by destroying single side vestibule of wistar rat. In the study the rats were divided into 3 groups: Group A 16 normal rats; Group B 15 rats, after 7 days of left vestibular damage; Group C 7 rats 3 months after left vestibular damage; and Group D 7 rats, after vestibular compensation. Electromyography of the rats was recorded and the expression of calcitonin gene relative peptide (CGRP), choline acetyltransferase (AChT) and Na-K-ATPase were investigated in efferent vestibular nervous system.


RESULTS
Electric potential activity of muscles of injury side decreased while that of the opposite side increased. In animals of vestibular compensation electric potential of bilateral musculus longus capitis at quiescent stage recovered symmetrically. CGRP positive cells of efferent vestibular nervous system increased bilaterally, and their activity enhanced, especially obvious at the acute stage. AChT positive cells of injury side of efferent vestibular nervous system decreased, but reaction degree of two sides enhanced. Reaction degree of the opposite side enhanced obviously at the stage of vestibular compensation. Expression of Na-K-ATPase mRNA of the same side was lower, but vestibular signal of the opposite side enhanced, clinically head and neck inclined obliquely by means of medial fasciculus of tractus vestibulospinalis. Months later, vestibular signal of the same side enhanced, and that of the opposite side enhanced also, clinical symptoms improved slightly. At the vestibular compensation stage, expression of Na-K-ATPase mRNA of the same side enhanced, and it was same as that of the opposite side or much higher, clinically it reached vestibular compensation.


CONCLUSIONS
Comprehensive effect of the above results maybe as follows: Efferent vestibular nervous system inhibited afferent signal of the opposite vestibule, and it modulated excitement of vestibular center of the same side, and it worked in the complicated mechanisms of vestibular compensation. CGRP may have facilitation function to the vestibular afferent signal of injury side. While Ach improved vestibule compensation by means of inhibition of vestibule excitement of the healthy side.
Chi
Fang-Lu
FL
Department of Otorhinolaryngology, Eye and Ear Nose & Throat Hospital, Medical School of Fudan University, Shanghai 200031, China. fangluchi@yahoo.com
Jiao
Yu
Y
Yuan
Ya-Sheng
YS
Wang
Zheng-Min
ZM
Li
Kuan-Yan
KY
Wu
Li-Wen
LW
D000344:Afferent Pathways / Q000378:metabolism*; D000818:Animals; D004525:Efferent Pathways / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014725:Vestibular Nerve / Q000378:metabolism*; D014722:Vestibule, Labyrinth / Q000378:metabolism*
D000254:Sodium-Potassium-Exchanging ATPase