RESUMO
BACKGROUND AND OBJECTIVES: Aminoglycoside antibiotics are widely used for the treatment of infection caused by Gram-negative bacilli, but prolonged exposure to it can cause permanent hearing loss since are reported to interrupt the function of medial olivocochlear bundle. This study was designed to explore the effects of several aminoglycoside antibiotics on acetylcholine, the neurotransmitter of medial olivocochlear bundle, and how it affects potassium currents of the guinea pig outer hair cells. MATERIALS AND METHOD: Using extracted outer hair cells from Guinea pigs, potassium currents induced by acetylcholine were recorded using the whole-cell patch clamp technique. The effects of different aminoglycoside antibiotics on the potassium current were also studied. RESULTS: Acetylcholine increased the potassium currents of outer hair cells. All of aminoglycoside antibiotics tested such as neomycin, streptomycin, gentamicin, and amikacin decreased the acetylcholine-induced potassium current. CONCLUSION: These experimental results suggest that aminoglycoside antibiotics have effects on the membrane potential of outer hair cells regulated by acetylcholine, which is thought to be one of the mechanisms of aminoglycoside ototoxicity.
