Santarelli Rosamaria, Arslan Edoardo, Carraro Luigi, Conti Guido, Capello Massimo, Plourde Gilles
Department of Medical and Surgical Specialities, Service of Audiology and Phoniatrics, University of Padua, Italy.
Acta Otolaryngol. 2003 Jan;123(2):176-81. doi: 10.1080/0036554021000028108.
To evaluate the effects of a volatile anesthetic, isoflurane, on auditory brainstem responses (ABRs) and middle latency responses (MLRs) recorded in rats.
ABRs and MLRs evoked by click stimuli were simultaneously recorded in eight rats in the awake condition and during anesthesia with isoflurane at clinically relevant concentrations.
Vertex-recorded ABRs showed a significant increase in the latency of waves I-IV during anesthesia and the latency changes appeared to be significantly related to the isoflurane concentration. The I-IV interval also appeared to be significantly increased in comparison to the awake condition, while minor changes in ABR amplitudes were induced by isoflurane. MLRs, which were recorded by means of epidural electrodes implanted over the auditory cortex, appeared to be attenuated in amplitude and increased in latency during anesthesia. Only latency changes appeared to be significantly related to the isoflurane concentration. Moreover, "bursts" of high amplitude MLRs were observed during anesthesia at each concentration.
The present findings indicate that both ABR and MLR latencies are increased by isoflurane in a concentration-dependent manner, whilst the anesthetic-induced attenuation in amplitude does not appear to be related to the isoflurane concentration.
评估挥发性麻醉剂异氟烷对大鼠听觉脑干反应（ABR）和中潜伏期反应（MLR）的影响。
在八只大鼠清醒状态下以及使用临床相关浓度的异氟烷麻醉期间，同时记录由短声刺激诱发的ABR和MLR。
顶点记录的ABR显示，麻醉期间波I-IV的潜伏期显著增加，且潜伏期变化似乎与异氟烷浓度显著相关。与清醒状态相比，I-IV间期似乎也显著增加，而异氟烷仅引起ABR幅度的轻微变化。通过植入听觉皮层上方的硬膜外电极记录的MLR，在麻醉期间幅度减弱，潜伏期延长。只有潜伏期变化似乎与异氟烷浓度显著相关。此外，在每个浓度的麻醉期间均观察到高幅度MLR的“爆发”。
目前的研究结果表明，异氟烷以浓度依赖的方式增加ABR和MLR的潜伏期，而麻醉引起的幅度减弱似乎与异氟烷浓度无关。
