[Effects of streptomycin on ionic currents in isolated outer hair cells of guinea pig cochlea].

The effects of streptomycin on ionic currents in outer hair cells isolated from the cochlea of guinea pig were investigated using a whole-cell recording patch-clamp technique. External application of streptomycin (1 mmol/L) caused a decrease of the potassium currents and calcium currents, respectively. The half-maximal inhibition concentration of streptomycin checking the voltage-dependent calcium currents was 56.08 mumol/L, and the ratio of maximal inhibition 21.71%. The present results demonstrate that streptomycin partially irreversibly blocks the voltage-dependent calcium currents in dissociated outer hair cells of guinea pig cochlea in a concentration-dependent manner. The effects of streptomycin of the potassium currents may be, at least in part, the result of the inhibition of Ca2+ influx. It suggests that the inhibition of Ga2+ influx may be one of the ototoxic mechanisms of streptomycin on outer hair cells.