Contralateral suppression of transient evoked otoacoustic emissions in guinea-pigs: effects of gentamicin.

A single injection of gentamicin in the awake guinea-pig induces a transient blockade of the suppression by contralateral white noise of tone-pip evoked compound action potential (Smith et al., 1994). We report here the reversible blockade, in exactly the same experimental conditions, of the suppression of click-evoked otoacoustic emissions. These observations confirm the transient action of gentamicin at the medial efferent/outer hair cell synapse, likely via the reversible blockade of calcium channels observed in vitro (Dulon et al., 1989).