Effect of the Level of Anesthesia on the Auditory Brainstem Response in the Emei Music Frog (Babina daunchina).

Jianguo Cui,Bicheng Zhu,Steven E Brauth,Ed Smith,Yezhong Tang,Guangzhan Fang,Manuel S Malmierca

doi:10.1371/journal.pone.0169449

Abstract

Anesthesia is known to affect the auditory brainstem response (ABR) in mice, rats, birds and lizards. The present study investigated how the level of anesthesia affects ABR recordings in an amphibian species, Babina daunchina. To do this, we compared ABRs evoked by tone pip stimuli recorded from 35 frogs when Tricaine methane sulphonate (MS-222) anesthetic immersion times varied from 0, 5 and 10 minutes after anesthesia induction at sound frequencies between 0.5 and 6 kHz. ABR thresholds increased significantly with immersion time across the 0.5 kHz to 2.5 kHz frequency range, which is the most sensitive frequency range for hearing and the main frequency range of male calls. There were no significant differences for anesthetic levels across the 3 kHz to 6 kHz range. ABR latency was significantly longer in the 10 min group than in the 0 and 5 min groups at frequencies of 0.5, 1.0, 1.5, 2.5 kHz, while ABR latency did not differ across the 3 kHz to 4 kHz range and at 2.0 kHz. Taken together, these results show that the level of anesthesia affects the amplitude, threshold and latency of ABRs in frogs.

Highlights

Many studies have investigated acoustic communication in anuran species [1,2,3,4]; fewer have used electrophysiological methods to investigate hearing sensitivity in these species [2, 5,6,7,8]
Previous studies have shown that for humans and most animals, the auditory brainstem response (ABR) is not affected by sleep and/or sedation [33,34]
The ABR is affected by anesthesia in some animals including mice, rats and lizards [15,16,17,18,19,20]

Summary

Introduction

Many studies have investigated acoustic communication in anuran species [1,2,3,4]; fewer have used electrophysiological methods to investigate hearing sensitivity in these species [2, 5,6,7,8]. The auditory brainstem response (ABR) provides a good estimate of the shape of the behavioral audiogram [5, 9,10,11,12] and is an extremely useful tool for studying hearing sensitivity as well as the functionality of the auditory system. Experimental electrophysiological recordings of the auditory system are frequently performed under anesthesia. General anesthesia is necessary to prevent movement of the animal

Methods

Results

Conclusion