Document Detail


Immunohistochemical localization of adenosine 5'-triphosphate-gated ion channel P2X(2) receptor subunits in adult and developing rat cochlea.
MedLine Citation:
PMID:  10813788     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Substantial in vitro and in vivo data support a role for extracellular adenosine 5;-triphosphate (ATP) and associated P2 receptors in cochlear function. However, the precise spatiotemporal distribution of the involved receptor protein(s) has not been determined. By using a specific antiserum and immunoperoxidase labeling, the tissue distribution of the P2X(2) subunit of the ATP-gated ion channel was investigated. Here, we describe the first extensive immunohistochemical mapping of P2X(2) receptor subunits in the adult and developing rat cochlea. In the adult, immunoreactivity was observed in most cells bordering on the endolymphatic compartment (scala media), particularly in the supporting cells. Hair cells were not immunostained by the P2X(2) antiserum, except for outer hair cell stereocilia. In addition, weak immunolabeling was observed in some spiral ganglion neurons. P2X(2) receptor subunit protein expression during labyrinthine ontogeny was detected first on embryonic day 19 in the spiral ganglion and in associated nerve fibers extending to the inner hair cells. Immunostaining also was observed underneath outer hair cells, and, by postnatal day 6 (P6), intense immunolabeling was seen in the synaptic regions of both types of hair cell. Supporting cells of the sensory epithelium were labeled at P0. This labeling became most prominent from the onset of cochlear function (P8-P12). Conversely, expression in the vascular stria declined from this time. By P21, the pattern of immunolabeling was similar to that found in the adult. The localization and timing of P2X(2) immunoreactivity suggest involvement of extracellular ATP and associated ATP-gated ion channels in important physiological events, such as inner ear ontogeny, sound transduction, cochlear micromechanics, electrochemical homeostasis, and auditory neurotransmission.
Authors:
L E Järlebark; G D Housley; P R Thorne
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of comparative neurology     Volume:  421     ISSN:  0021-9967     ISO Abbreviation:  J. Comp. Neurol.     Publication Date:  2000 Jun 
Date Detail:
Created Date:  2000-07-25     Completed Date:  2000-07-25     Revised Date:  2010-01-14    
Medline Journal Info:
Nlm Unique ID:  0406041     Medline TA:  J Comp Neurol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  289-301     Citation Subset:  IM    
Copyright Information:
Copyright 2000 Wiley-Liss, Inc.
Affiliation:
Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphate / metabolism*
Animals
Cochlea / growth & development,  metabolism*
Female
Hair Cells, Auditory, Inner / growth & development,  metabolism
Hair Cells, Auditory, Outer / growth & development,  metabolism
Ion Channels / metabolism*
Pregnancy
Rats
Rats, Wistar
Receptors, Purinergic P2 / metabolism*
Spiral Ganglion / growth & development,  metabolism
Chemical
Reg. No./Substance:
0/Ion Channels; 0/Receptors, Purinergic P2; 0/purinergic P2X2 receptor; 56-65-5/Adenosine Triphosphate

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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