Effect of the Anesthetic Tricaine (MS-222) on Nerve Activity in the Anterior Lateral Line of the Oyster Toadfish,Opsanus tau

Abstract

Inductive neural telemetry was used to record from microwire electrodes chronically implanted into the anterior lateral line nerve of the toadfish, Opsanus tau. Spontaneous neural activity and the response of lateral line fibers to water current were continually monitored from 17 primary afferent fibers before, during, and after the administration of the anesthetic tricaine (MS-222). Significant decrease in spontaneous and evoked activity and increase in interspike interval was noted when anesthetic concentrations were >/=0.010%. Neural activity returned to control levels within approximately 90 min of anesthetic withdrawal. Decreasing the pH of the solution without the anesthetic caused transient heightened sensitivity, indicating that tricaine and not the concurrent drop in pH was responsible for the decrease in sensitivity during anesthesia. During a secondary challenge with the anesthetic 24 h after the first, fibers initially showed faster recovery however overall recovery kinetics were similar. Although high tricaine concentration was correlated with decreased neural sensitivity, the concentrations normally used to maintain anesthesia in the toadfish did not have significant effect on the evoked firing rate. Thus given sufficient time to recover from the induction of surgical anesthesia, it may be possible to maintain the animal under light anesthesia while minimizing the physiological effects of tricaine.

The use of anesthesia during evoked potential audiometry in goldfish (Carassius auratus)

“…We did not find a similar reduction of AEP amplitude following brief sedation using 0.01% MS222. The difference may be due to the compound nature of the AEP, as opposed to the single unit activity recorded by Palmer and Mensinger (2004). More likely, it is due to the brevity of MS222 exposure in the present report.…”

“…Palmer and Mensinger (2004) showed that anesthesia with MS-222 at dosages greater than 0.01% decreases spontaneous and stimulus-evoked activity in anterior lateral line nerve afferents. We did not find a similar reduction of AEP amplitude following brief sedation using 0.01% MS222.…”

“…The most commonly-used anesthetic is tricaine methanesulfonate , which is known to interfere with sensory function in fish (Hensel at al., 1975;Spath and Schweickert, 1977;Arnolds et al, 2002,Palmer andMensinger, 2004). When used to prepare animals for single-unit recordings, experimenters routinely postpone data collection for approximately one hour following MS-222 administration.…”

“…While it has been assumed that MS-222 anesthesia has minimal lasting effects on the AEP, this has not been empirically assessed as during single unit recordings (Palmer and Mensinger, 2004). Further, prolonged pharmacological paralysis in the absence of anesthesia is potentially distressing to the subject and could induce stress-related changes in sensory function and/or evoked potential waveforms.…”

Early Development of Hearing in Zebrafish

“…The 0.009 % MS-222 concentration used in this study can sufficiently anesthetize one-week old zebrafish. Palmer and Mensinger (2004) reported that MS-222 concentrations lower than 0.01 % did not significantly reduce either spontaneous or evoked responses of sensory fibers innervating hair cells in the anterior lateral line of the toadfish. Although they did observe suppression of lateral line afferent response at higher MS-222 concentrations, it is not known whether the suppressive effects result from MS-222 action on hair cells, sensory afferents, or both.…”