title: Kölliker's organ and the development of spontaneous activity in the auditory system: implications for hearing dysfunction.
abstract: Prior to the "onset of hearing," developing cochlear inner hair cells (IHCs) and primary auditory neurons undergo experience-independent activity, which is thought to be important in retaining and refining neural connections in the absence of sound. One of the major hypotheses regarding the origin of such activity involves a group of columnar epithelial supporting cells forming Kölliker's organ, which is only present during this critical period of auditory development. There is strong evidence for a purinergic signalling mechanism underlying such activity. ATP released through connexin hemichannels may activate P2 purinergic receptors in both Kölliker's organ and the adjacent IHCs, leading to generation of electrical activity throughout the auditory system. However, recent work has suggested an alternative origin, by demonstrating the ability of IHCs to generate this spontaneous activity without activation by ATP. Regardless, developmental abnormalities of Kölliker's organ may lead to congenital hearing loss, considering that mutations in ion channels (hemichannels, gap junctions, and calcium channels) involved in Kölliker's organ activity share strong links with such types of deafness.
authors.affiliation: Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand ; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: M W Nishani
authors.initials: MW
authors.lastname: Dayaratne
authors.affiliation: Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand ; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Srdjan M
authors.initials: SM
authors.lastname: Vlajkovic
authors.affiliation: Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand ; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Janusz
authors.initials: J
authors.lastname: Lipski
authors.affiliation: Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand ; Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand ; Section of Audiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Thorne
mesh_terms: D003056:Cochlear Nerve / Q000378:metabolism / Q000473:pathology; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism / Q000473:pathology*; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000235:genetics / Q000473:pathology*; D006801:Humans; D065836:Kolliker-Fuse Nucleus / Q000378:metabolism / Q000473:pathology*; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D018048:Receptors, Purinergic P2