Nicotinic Receptors of Cochlear Hair Cells: A Possible Pharmacotherapeutic Target?

ANA BELÉN ELGOYHEN; ELEONORA KATZ; PAUL A FUCHS

BIOCHEMICAL PHARMACOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2009 vol. 78 p. 712 - 719

0006-2952

Mechanosensory hair cells of the organ of Corti transmit information regarding sound to the central nervous system by way of peripheral afferent neurons. In return, the central nervous system provides feedback  and  modulates  the afferent stream  of  information through  efferent  neurons.  The  medial olivocochlear  efferent  system  makes  direct  synaptic  contacts  with  outer  hair  cells  and  inhibits amplification brought about by the active mechanical process inherent to these cells. This feedback system offers the potential to improve the detection of signals in background noise, to selectively attend to  particular  signals,  and  to  protect  the  periphery  from  damage  caused  by  overly  loud  sounds.Acetylcholine released at the synapse between efferent terminals and outer hair cells activates a peculiar nicotinic  cholinergic  receptor  subtype,  the  alpha9alpha10  receptor.  At  present  no  pharmacotherapeutic approaches have been designed that target this cholinergic receptor to treat pathologies of the auditory system. The potential use of alpha9alpha10 selective drugs in conditions such as noise-induced hearing loss, tinnitus and auditory processing disorders is discussed.