The expression of muscarinc acetylcholine receptors on the avian vestibular hair cells and the modulation effects on KIR2.1

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dc.contributor.advisor Manning J . Correia , en_US
dc.contributor.committeeMember Thomas G . Wood , en_US
dc.contributor.committeeMember S .V . Penelope Jones en_US
dc.contributor.committeeMember Robert B . Leonard en_US
dc.contributor.committeeMember Malcolm S . Brodwick en_US
dc.contributor.committeeMember Joseph C . Holt en_US
dc.contributor.committeeMember Golda A . Leonard en_US
dc.creator Gang Q Li en_US 2011 -12 -20T16 :05 :41Z 2014 -02 -19T22 :05 :48Z 2010 -09 -28 en_US 2011 -12 -20T16 :05 :41Z 2014 -02 -19T22 :05 :48Z 2008 -12 -05 en_US 2008 -11 -26 en_US
dc.identifier.other etd -12052008 -210715 en_US
dc.identifier.uri http : / /hdl .handle .net /2152 .3 /286
dc.description.abstract The major neurotransmitter released from the vestibular efferent terminals onto hair cells is acetylcholine (ACh ) . Two types of acetylcholine receptors (AChRs ) have been suggested to be located on hair cells (HCs ) . They were nicotinic receptors (nAChRs ) and muscarinic receptors (mAChRs ) . Even though pioneering physiological and pharmacological studies have shown evidence of mAChR located on the HCs , the protein expression and the role of muscarinic acetylcholine receptor (mAChR ) in HCs have not been carefully studied . Our preliminary data indicated that the activation of mAChRs on pigeon vestibular type II HCs produced an inhibitory effect on an inward rectifier potassium channel , Kir2 .1 . Using immunohistochemical , immunocytochemical , and Western blot techniques , we demonstrated for the first time , the expression and co -expression of mAChR subtypes M1 -M5 on the peripheral vestibular structures , including hair cells , supporting cells , ganglion , and other neural elements . To better understand the modulation effects of mAChR activation on Kir2 .1 channels , the heterologous expression system (HES ) was used to express a single mAChR subtype and Kir2 .1 . The expression plasmids for M3 or M5 mAChR subtype were co -transfected with pKir2 .1 into the mammalian cell line tsA201 cells and electrophysiological studies including whole cell voltage clamp and current clamp were performed . Muscarinic receptor agonist (CCh ) application to the tsA201 cells transfected with M3 &pKir2 .1 or M5 &pKir2 .1 exhibited concentration - and time - dependent facilitatory and /or inhibitory effects on the pKir2 .1 channels . These effects depolarized or hyperpolarized the cell membrane potential , respectively . Further electrophysiological experiments were performed on native isolated \r \nvii \r \navian (pigeon ) vestibular HCs . Whole cell patch clamp on both type I and type II HCs indicated that mAChR activation decreased both inward and outward current (type I & type II ) which consequently produced hyperpolarization (type II ) and depolarization (type I & type II ) . We also noticed that nAChR activation increased the outward current (type I & type II ) and inward current (type II ) which hyperpolarized the membrane potential (type I & type II ) or depolarized the membrane potential (type II ) . In conclusion , mAChR played a role in the control of membrane potentials by modulating the ionic channels . The mechanism of mAChR induced effects is still unknown . en_US
dc.format.medium electronic en_US
dc.language.iso eng en_US
dc.rights Copyright © is held by the author . Presentation of this material on the TDL web site by The University of Texas Medical Branch at Galveston was made possible under a limited license grant from the author who has retained all copyrights in the works . en_US
dc.subject vestibular en_US
dc.subject tsA201 en_US
dc.subject potassium channel en_US
dc.subject muscarinic receptor en_US
dc.subject hair cell en_US
dc.subject acetylcholine en_US
dc.title The expression of muscarinc acetylcholine receptors on the avian vestibular hair cells and the modulation effects on KIR2 .1 en_US
dc.type.genre dissertation en_US
dc.type.material text en_US PhD en_US Doctoral en_US The University of Texas Medical Branch en_US Neuroscience en_US


The expression of muscarinc acetylcholine receptors on the avian vestibular hair cells and the modulation effects on KIR2.1. Doctoral dissertation, The University of Texas Medical Branch. Available electronically from http : / /hdl .handle .net /2152 .3 /286 .

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