Esketamine may be an ideal substitute for ketamine during cochlear function measurement

Area of Science:

• Otoacoustic Emissions
• Auditory Neuroscience
• Pharmacology

Background:

• Ketamine and xylazine mixtures are standard for auditory brainstem response (ABR) measurements.
• Esketamine is a more potent enantiomer of ketamine.

Purpose of the Study:

• To evaluate esketamine's efficacy as a substitute for ketamine in cochlear function assessments.
• To compare the effects of ketamine/xylazine versus esketamine/xylazine on hearing function and anesthetic recovery in mice.

Main Methods:

• C57Bl/6J mice received equivalent analgesic doses of either ketamine/xylazine or esketamine/xylazine via intraperitoneal injection.
• Auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) thresholds were measured.
• Anesthetic recovery times (time to loss and regain of righting reflex) were recorded.

Main Results:

• Hearing thresholds, ABR wave latencies (I and V), and DPOAE thresholds were comparable between the ketamine and esketamine groups (P>0.05).
• Mice treated with esketamine showed a significantly shorter time to regain righting reflex compared to the ketamine group (P<0.001).

Conclusions:

• Esketamine, at equivalent analgesic doses, is a viable alternative to ketamine for cochlear function testing.
• Esketamine offers a faster recovery profile from anesthesia compared to ketamine in this experimental model.