title: Spatiotemporal pattern of action potential firing in developing inner hair cells of the mouse cochlea.
abstract: Inner hair cells (IHCs) are the primary transducer for sound encoding in the cochlea. In contrast to the graded receptor potential of adult IHCs, immature hair cells fire spontaneous calcium action potentials during the first postnatal week. This spiking activity has been proposed to shape the tonotopic map along the ascending auditory pathway. Using perforated patch-clamp recordings, we show that developing IHCs fire spontaneous bursts of action potentials and that this pattern is indistinguishable along the basoapical gradient of the developing cochlea. In both apical and basal IHCs, the spiking behavior undergoes developmental changes, where the bursts of action potential tend to occur at a regular time interval and have a similar length toward the end of the first postnatal week. Although disruption of purinergic signaling does not interfere with the action potential firing pattern, pharmacological ablation of the α9α10 nicotinic receptor elicits an increase in the discharge rate. We therefore suggest that in addition to carrying place information to the ascending auditory nuclei, the IHCs firing pattern controlled by the α9α10 receptor conveys a temporal signature of the cochlear development.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1051, Institut des Neurosciences de Montpellier, 34091 Montpellier, France.
authors.forename: Gaston
authors.initials: G
authors.lastname: Sendin
authors.forename: Jérôme
authors.initials: J
authors.lastname: Bourien
authors.forename: François
authors.initials: F
authors.lastname: Rassendren
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Puel
authors.forename: Régis
authors.initials: R
authors.lastname: Nouvian
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D059329:Cholinergic Neurons / Q000187:drug effects / Q000502:physiology; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D015398:Signal Transduction / Q000187:drug effects; D062211:Spatio-Temporal Analysis
chemical_list: D000255:Adenosine Triphosphate
keywords: ATP receptor; acetylcholine receptor; auditory system; electrical activity