Cordova Micah S, Braun Christopher B
Department of Psychology, Hunter College (CUNY, New York City, NY 10021, USA.
Brain Res. 2007 Jun 11;1153:78-83. doi: 10.1016/j.brainres.2007.03.055. Epub 2007 Mar 24.
Auditory-evoked potentials (AEPs) have become a widely utilized measure of hearing sensitivity. Most investigators use pharmacological paralysis to reduce myogenic noise and immobilize the animal for stable electrical recordings, but additional anesthesia is generally not used because the most commonly available fish anesthetic, the cholinergic antagonist tricaine methanosulfate (MS222), is known to disrupt hair cell and primary afferent physiology. Anesthetic agents that do not interfere with auditory function would be a useful adjunct to paralytic immobilization and would reduce any possible distress incurred by prolonged immobilization. In this report we tested the opiate anesthetic fentanyl and compared hearing thresholds in immobilized versus immobilized and anesthetized animals. Short-term effects of mild MS222 anesthesia were also measured via evoked potential audiometry. Animals were tested before and after fentanyl injection (100, 500 and 2500 microg g(-1) fish body-weight) using standard evoked potential audiometry. Tone pips, 0.2-3 kHz, from an aerial loudspeaker served as stimuli. Fentanyl altered evoked potential waveforms slightly but did not alter estimated threshold sensitivity. These results suggest fentanyl be considered as a possible addition to AEP techniques in goldfish (Carassius auratus) and poikilothermic vertebrates generally.
听觉诱发电位（AEPs）已成为一种广泛应用的听力敏感度测量方法。大多数研究人员使用药物麻痹来减少肌源性噪声并固定动物以进行稳定的电记录，但一般不使用额外的麻醉，因为最常用的鱼类麻醉剂，胆碱能拮抗剂甲磺酸三卡因（MS222），已知会干扰毛细胞和初级传入神经的生理功能。不干扰听觉功能的麻醉剂将是麻痹固定的有用辅助手段，并将减少长时间固定可能带来的任何痛苦。在本报告中，我们测试了阿片类麻醉剂芬太尼，并比较了固定动物与固定并麻醉动物的听力阈值。还通过诱发电位测听法测量了轻度MS222麻醉的短期效果。使用标准诱发电位测听法在注射芬太尼（100、500和2500μg g(-1)鱼体重）前后对动物进行测试。来自空气扬声器的0.2 - 3kHz的短音作为刺激。芬太尼略微改变了诱发电位波形，但没有改变估计的阈值敏感度。这些结果表明，芬太尼可被视为金鱼（Carassius auratus）和一般变温脊椎动物AEP技术的一种可能补充。
