Poje C P, Sewell D A, Saunders J C
Division of Otolaryngology, Children's Hospital of Philadelphia, PA, USA.
Hear Res. 1995 Feb;82(2):197-204. doi: 10.1016/0378-5955(94)00177-r.
Chicks were exposed to an intense pure tone (0.9 kHz, 120 dB SPL) for 48 h. The DC endocochlear potential was measured with a microelectrode inserted into scala media in six separate groups of animals between 0 and 12 days post exposure. Similar data were obtained from seven groups of unexposed control chicks between 2 and 15 days of age. One to nine animals were tested in each control or exposed group. The results in the control chicks revealed that the EP at 2 days of age (6.7 mV) was 36% of the mature value (15.2 mV) noted at 6 days of age. In the exposed animals, at 0-days recovery, the EP showed a 63% reduction relative to that measured in age matched control chicks. The level of EP in the exposed animals quickly recovered, and by 3 and 6 days post exposure exhibited a loss of only 7 and 3 percent relative to the age-matched controls. The recovery of EP was plotted against the recovery of evoked potential thresholds reported by others, and the time-course of the recovery functions were very similar. This relationship suggested that recovery of auditory function in the chick was highly correlated with the restoration of the EP. Damage to the tegmentum vasculosum and its capacity to secrete potassium, as well as the shunting of current through the damaged basilar papilla, are considered as mechanisms for the reduction of EP loss in the exposed ear.
将雏鸡暴露于强度为120 dB SPL的0.9 kHz纯音下48小时。在暴露后0至12天内，用微电极插入中阶，对六组不同的动物测量直流内淋巴电位。从七组2至15日龄未暴露的对照雏鸡中获得了类似的数据。每个对照组或暴露组测试1至9只动物。对照雏鸡的结果显示，2日龄时的内淋巴电位（6.7 mV）是6日龄时成熟值（15.2 mV）的36%。在暴露的动物中，暴露后0天恢复时，内淋巴电位相对于年龄匹配的对照雏鸡测量值降低了63%。暴露动物的内淋巴电位水平迅速恢复，暴露后3天和6天相对于年龄匹配的对照仅损失7%和3%。将内淋巴电位的恢复情况与其他人报告的诱发电位阈值的恢复情况进行了绘制，恢复函数的时间进程非常相似。这种关系表明，雏鸡听觉功能的恢复与内淋巴电位的恢复高度相关。血管纹损伤及其分泌钾的能力，以及电流通过受损基底乳头的分流，被认为是暴露耳内淋巴电位损失减少的机制。
