Abstract
On etiology of aminoglycoside ototoxication, basic particulars such as ionic environments, membrane properties, transduction channels and presynaptic events in hair cells should be considered. The ionic environment of the apical surface of hair cells is characterized by a high concentration of potassium and a very low concentration of calcium. This calcium content is necessary for maintaining the gating action of the transduction channels. It seems likely that triphosphoinositide is a candidate for the binding site of calcium which is competed with aminoglycoside. It has been also reported that the aminoglycoside competes with calcium at the basolateral side of hair cells. The aminoglycoside acts in two phases on the basolateral side in which the actions are reversible and irreversible. There is a difference in causing process of aminoglycoside ototoxication between the apical side and the basolateral side.
