Tohoku J. Exp. Med., 2003, 200 (4)

Involvement of Poly(ADP-Ribose) Synthetase in
Acoustic Trauma of The Cochlea

KEIJI TABUCHI, TOMOHUMI HOSHINO, HIDEKAZU MURASHITA, KEIKO OIKAWA,
ISAO UEMAETOMARI, BUNGO NISHIMURA, TADAMICHI TOBITA and AKIRA HARA

Department of Otolaryngology, Institute of Clinical Medicine, University of Tsukuba, Tsukuba 305-8575

We investigated effects of poly(ADP-ribose) synthetase (PARS) inhibitors on acoustic trauma. Albino guinea pigs were intravenously given 3-aminobenzamide, nicotinamide or 3-aminobenzoic acid (an inactive analog of 3-aminobenzamide) just prior to exposure to a 2 kHz pure tone of 120 dB sound pressure level (SPL) for 10 minutes. The threshold of the compound action potential (CAP) and the amplitude of distortion-product otoacoustic emissions (DPOAEs) were measured before and 4 hours after the acoustic overexposure. Statistically significant decreases in the CAP threshold shifts and significant increases in the DPOAE amplitudes were observed 4 hours after the acoustic overexposure in the animals treated with 3-aminobenzamide or nicotinamide, whereas 3-aminobenzoic acid did not exert any protective effect. These results strongly suggest that excessive activation of PARS is involved in generation of the acoustic trauma.

keywords —— Acoustic trauma; Cochlea; Poly(ADP-ribose) synthetase (PARS)

© 2003 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2003, 200, 195-202

Address for reprints: Keiji Tabuchi, Department of Otolaryngology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan.

e-mail: ktabuchi@md.tsukuba.ac.jp