Shehata-Dieler W E, Richter C P, Dieler R, Klinke R
Department of Otolaryngology-Head and Neck Surgery, University of Würzburg, FRG.
Hear Res. 1994 Apr;74(1-2):77-84. doi: 10.1016/0378-5955(94)90177-5.
The effects of salicylate on the mammalian cochlea function are well documented. However, there is a lack of reports on salicylate effects on the avian auditory periphery and it might well be that salicylate is not ototoxic at all in submammalian vertebrates. We therefore recorded single fiber activities, compound action potential (CAP) and endocochlear potential (EP) during application of salicylate (calculated final concentration of about 2-18 mmol/l) into the scala media of pigeons. We furthermore recorded CAP and EP during perilymphatic perfusion of salicylate (2-20 mmol/l). Salicylate applied into the scala media led to an elevation of tip threshold in single fibers ranging from 5 to 35 dB. The characteristic frequencies of the fibers were not changed. This effect on auditory nerve fibers was reflected in an elevation of CAP thresholds. The mean spontaneous discharge rate was either slightly increased or remained unchanged in the majority of fibers. Perilymphatic salicylate perfusion also led to an elevation of CAP thresholds that was reversible following subsequent perfusion with artificial perilymph. The EP remained unchanged in both application modes. The effects of salicylate were dose dependent and more pronounced in the mid- to high-frequency range. These results are consistent with an action of salicylate on the process (electrical or mechanical, or both) responsible for the sensitivity and frequency selectivity in the avian peripheral hearing organ.
水杨酸盐对哺乳动物耳蜗功能的影响已有充分记录。然而，关于水杨酸盐对鸟类听觉外周的影响却缺乏相关报道，而且在非哺乳类脊椎动物中水杨酸盐很可能根本没有耳毒性。因此，我们在向鸽子的中阶施加水杨酸盐（计算得出的最终浓度约为2 - 18 mmol/l）的过程中记录了单纤维活动、复合动作电位（CAP）和内淋巴电位（EP）。此外，我们还在进行水杨酸盐（2 - 20 mmol/l）外淋巴灌注时记录了CAP和EP。向中阶施加水杨酸盐会导致单纤维的尖端阈值升高5至35分贝。纤维的特征频率没有改变。这种对听神经纤维的影响反映在CAP阈值的升高上。大多数纤维的平均自发放电率要么略有增加，要么保持不变。外淋巴灌注水杨酸盐也会导致CAP阈值升高，在随后用人造外淋巴灌注后这种升高是可逆的。在两种施加方式下EP均保持不变。水杨酸盐的作用具有剂量依赖性，并且在中高频范围内更为明显。这些结果与水杨酸盐对鸟类外周听觉器官中负责灵敏度和频率选择性的过程（电过程或机械过程，或两者兼有）的作用一致。
