Effect of nicotine on cochlear function and noise-induced hair cell loss.

Nicotine administered in high doses intravenously (1 mg/kg) and intracochlearly (10 mM) exhibited very little effect on guinea pig cochlear potentials. When administered chronically (1-20 mg/kg, i.p. for 20 days), nicotine demonstrated no effect on cochlear potentials or the number of observed hair cell scars monitored 21 days after the treatment was terminated. Neither chronic nicotine treatment (1-20 mg/kg, i.p. for 20 days) nor acute reserpine pretreatment (5 mg/kg, i.p. 24 hours before) altered the hair cell damaging effects of an intense pure tone (4 kHz, 126 dB SPL, 30 min). No nicotine ototoxicity was detected by the methods used in this study.