Experimental study on recovery mechanism of body balance after vestibular damage

庆大霉素（Gentamicin）给药后的行为变化。-GM）中毒和前庭神经切除术进行了研究。根据椭圆囊黄斑的损伤程度，视网膜内注射GM导致倾斜姿势。这种倾斜随着时间的推移而发展。从前庭神经节外周切断前庭神经。辙叉也持续向操作侧倾斜约30度。这种倾斜消失了，青蛙在4-9周内恢复正常姿势。显微镜下神经再生良好，感觉上皮正常。这一结果表明，前庭神经切断后，内器的激活和中枢代偿机制在姿势恢复中起重要作用。基于这一发现，进行了以下实验。在实验I中，在姿势恢复后再次切断右侧前庭神经。与第1次神经切断术相比，倾斜角度更小，恢复时间更短。这种现象可能是由于右侧脑区的中枢代偿作用所致。.在实验II中，在姿势恢复后切断左侧神经。左侧倾斜角度大于第1次神经切断。在实验III中，青蛙接受双侧神经切除术，并将一块骨头插入右侧神经的切断端以抑制神经再生。青蛙慢慢地向右边倾斜。这可能是由于左椭圆囊的功能重新激活，导致外周水平的前庭失衡。

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.