Kobayashi T, Itoh Z, Sakurada T, Shiga N, Takasaka T
Department of Otorhinolaryngology, Tohoku University School of Medicine, Sendai, Japan.
Acta Otolaryngol. 1990 Sep-Oct;110(3-4):209-16. doi: 10.3109/00016489009122539.
Perilymphatic fistula is now widely recognized to cause acute profound hearing loss. It is still controversial, however, which mechanism it is that causes the reversible hearing loss. Recently, it has been suggested by two groups of researchers that the intrusion of air bubbles into the perilymphatic space (a condition called pneumolabyrinth or aerolabyrinth) through the ruptured labyrinthine window(s) may be one of the causes. In order to examine the mechanism underlying the hearing loss associated with pneumolabyrinth, the perilymphatic space of the guinea pig cochlea was perfused with air and cochlear potentials were recorded. Although perfusion of the scala tympani with air at a rate as high as 200 microliter/min caused an immediate and drastic decrease of the cochlear microphonics (CM) and the compound action potential (AP), it had little effect on the endocochlear dc potential (EP) during perfusion for 20 min. A decline in EP was seen in half the ears, but only when the duration of perfusion exceeded 30 min. These results show that the EP has an amazing resistance to air trapped in the scala tympani of the cochlea and that the initial decrease of hearing acuity after the elimination of perilymph from the scala tympani (or introduction of air into the scala tympani) is probably due to interference in CM and AP generation mechanisms rather than to strial dysfunction.
目前人们普遍认为，外淋巴瘘可导致急性重度听力损失。然而，究竟是哪种机制导致了这种可逆性听力损失，仍存在争议。最近，两组研究人员提出，通过破裂的迷路窗，气泡侵入外淋巴间隙（一种称为气迷路的情况）可能是原因之一。为了研究与气迷路相关的听力损失的潜在机制，向豚鼠耳蜗的外淋巴间隙灌注空气，并记录耳蜗电位。尽管以高达200微升/分钟的速率向鼓阶灌注空气会导致耳蜗微音电位（CM）和复合动作电位（AP）立即大幅下降，但在灌注20分钟期间，对内耳直流电位（EP）几乎没有影响。半数耳朵的EP出现下降，但仅在灌注持续时间超过30分钟时才出现。这些结果表明，EP对被困在耳蜗鼓阶中的空气具有惊人的抵抗力，并且在鼓阶中的外淋巴被清除（或向鼓阶中引入空气）后，听力敏锐度最初的下降可能是由于CM和AP产生机制受到干扰，而不是由于血管纹功能障碍。
