Experimental study on recovery mechanism of body balance after vestibular damage

庆大霉素治疗后的行为改变(.-GM)中毒和前庭神经切断在牛蛙身上进行了研究。根据椭圆形黄斑损伤的程度，迷路内注射GM可导致倾斜姿势。这种倾斜是随着时间的推移而发展起来的。前庭神经外周切断至前庭神经节。青蛙还持续向手术侧倾斜约30度。这种倾斜消失了，青蛙在4-9周的时间里恢复了正常的姿势。显微镜下神经再生良好，感觉上皮细胞正常。这一结果表明，内脏神经节的重新激活和中枢代偿机制在前庭神经切除后的姿势恢复中起着重要作用。基于这一发现，进行了以下实验。实验一：体位恢复后再次切断右侧前庭神经。与第一次神经切断术相比，倾斜角度较小，恢复时间较短。右侧实现的中央补偿可能是造成这一现象的原因。。实验二：体位恢复后切断左侧神经。左侧倾斜角度大于第1次神经切断术。在实验三中，青蛙接受了双侧神经切除，并将一块骨插入右侧神经的断端，以抑制神经再生。青蛙慢慢地向右侧倾斜。这可能是由于左侧椭圆体功能重新激活，导致前庭外周水平失衡。

Behavioral change after Gentamicin(. -GM)intoxication and vestibular neurectomy was studied using bull frogs. Intralabyrinthine injection of GM resulted in tilting posture according to the degree of the damage to the utricular macula. This, tilting developed as the time lapsed. The vestibular nerve was cut peripherally to the vestibular ganglion. The frog also sustained tilting toward the operated side by about 30 degrees. This tilting disappeared and the frog returned to normal posture over the period of 4-9 weeks. Microscopically the sectioned nerve well regenerated and the sensory epithelia was normal. This result indicates that both reactivation of the endorgan and central compensatory mechanism play an essential role in postural recovery after vestibular neurectomy. Based upon this finding following experiments were done. In experiment I, the right vestibular nerve was again cut after postural recovery. The tilting angle was smaller and the recovery period was shorter than the 1st neurectomy. Central compensation achieved in the right side is possibly responsible for this phenomenon. . In experiment II, the left nerve was cut after postural recovery. The tilting angle toward the left was greater than that of the 1st neurectomy. In experiment III, the frog under-went bilateral neurectomy, and a piece of the bone was inserted into the cut ends of the right nerve to inhibit neural regeneration. The frog slowly developed tilting toward the right side. This is possibly due to reactivated function of the left utricle, which resulted in vestibular imbalance at the peripheral level.