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Cholinergic Responses in Developing Outer Hair Cells of the Rat Cochlea
Author(s) -
Dulon Didier,
Lenoir Marc
Publication year - 1996
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1996.tb01338.x
Subject(s) - acetylcholine , ionotropic effect , cholinergic , cochlea , acetylcholine receptor , chemistry , patch clamp , nicotinic agonist , neuroscience , biophysics , muscarinic acetylcholine receptor , biology , electrophysiology , endocrinology , receptor , biochemistry , nmda receptor
Abstract Acetylcholine‐evoked currents were investigated using the conventional whole‐cell patch‐clamp recording technique in developing outer hair cells (OHCs). The cells were isolated from the rat cochlea at different stages of postnatal development ranging from day 4 (P4) to P30. Acetylcholine‐evoked currents could be recorded at P6 and P8. At this developmental stage, the majority of OHCs displayed inward nicotinic‐like currents near the resting membrane potential. These cholinergic currents zeroed near 0 mV, as expected for a non‐selective cation current, and could be reversibly blocked by d‐tubocurarine. At P12 and adult stage, the cholinergic response of OHCs switched to an outward current reversing near E K and displaying a bell shape peaking between ‐40 and ‐30 mV. This change in polarity of the acetylcholine response during postnatal development might be explained by progressive functional coupling between acetylcholine ionotropic receptors permeable to Ca 2+ and nearby Ca 2+ ‐activated K + channels at the synaptic pole of OHCs.