Efferent Protection from Acoustic Injury Is Mediated via alpha 9 Nicotinic Acetylcholine Receptors on Outer Hair Cells

• Published in: The Journal of neuroscience Vol. 22; no. 24; pp. 10838 - 10846
• Main Authors: Maison, Stephane F, Luebke, Anne E, Liberman, M. Charles, Zuo, Jian
• Format: Journal Article
• Language: English
• Published: Soc Neuroscience 15.12.2002
• ISSN: 0270-6474; 1529-2401

Exposure to intense sound can damage the mechanosensors of the inner ear and their afferent innervation. These neurosensory elements are innervated by a sound-activated feedback pathway, the olivocochlear efferent system. One major component of this system is cholinergic, and known cholinergic effects are mediated by the alpha 9/ alpha 10 nicotinic acetylcholine receptor (nAChR) complex. Here, we show that overexpression of alpha 9 nAChR in the outer hair cells of bacterial artificial chromosome transgenic mice significantly reduces acoustic injury from exposures causing either temporary or permanent damage, without changing pre-exposure cochlear sensitivity to low- or moderate-level sound. These data demonstrate that efferent protection is mediated via the alpha 9 nAChR in the outer hair cells and provide direct evidence for a protective role, in vivo, of a member of the nAChR family.