Experimental study on the changes and regeneration of the cupula due to ototoxic drugs.

本文研究了机械振动对牛蛙和哺乳动物中耳耳膜脱离的影响。耳郭移入半规管腔内。这种情况被认为是BPPV的管结石模型。当耳蜗附着于丘表面时，即为丘结石模型。两种模型均抑制正弦旋转刺激引起的椎管神经活动。这被认为是BPPV患者热量反应和VOR降低的机制。用庆大霉素注射牛蛙内耳，观察牛蛙耳廓的变化。丘状体缩小到一半大小。然而，保持了锥体表面的粘性。减少的丘体积允许在头部变化时容易偏转，从而可能导致位置性眩晕的发生。壶体体积减小也使内淋巴通过壶腹壁逸出，从而可能导致管堵术后眩晕。

The effects of the changes in physical property of the semicircular canal cupula were studied Mechanical vibration to the middle ear induced detachment of the utricular otoconia both in bull frogs and mammals. The otoconia moved into semicircular canal lumen. This condition was regarded as a model of canalolithiasis of BPPV. When the otoconia were attached to the cupula surface, this was cupulolithiasis model. Both models suppressed the canal nerve activity induced by sinusoidal rotatory stimulus. This is considered to be a mechanism of decreased caloric response and VOR in BPPV patients. Gentamicin was injected into bullfrogs' inner ear and changes of the cupula were studied. The cupula was shrunken into about half size. However, the viscous nature of the cupula surface was maintained. Decreased cupula volume allows easy deflection upon head change, thus possibly leading to the occurrence of positional vertigo. Decreased cupula volume also allows the endolymph escape through ampullary wall, thus possibly leading to vertigo after canal plugging procedure.