Publication: The presence of opioid receptors in rat inner ear
Issued Date
2003-01-01
Resource Type
ISSN
03785955
Other identifier(s)
2-s2.0-0037677544
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Mahidol University
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SCOPUS
Bibliographic Citation
Hearing Research. Vol.181, No.1-2 (2003), 85-93
Suggested Citation
Nopporn Jongkamonwiwat, Pansiri Phansuwan-Pujito, Puangkeaw Sarapoke, Banthit Chetsawang, Stefano O. Casalotti, Andrew Forge, Hilary Dodson, Piyarat Govitrapong The presence of opioid receptors in rat inner ear. Hearing Research. Vol.181, No.1-2 (2003), 85-93. doi:10.1016/S0378-5955(03)00175-8 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/21012
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Title
The presence of opioid receptors in rat inner ear
Abstract
Opioid peptides have been identified in the inner ear but relatively little information is available about the expression and distribution of their receptors. The aim of the present study was therefore to identify and localize the μ (MOR), δ (DOR) and κ (KOR) opioid receptor subtypes within the rat cochlea. The expression of these opioid receptor subtypes was determined by reverse transcriptase-polymerase chain reaction followed by nested polymerase chain reaction analysis. Amplification of RNAs from rat cerebral cortex (positive control) and rat cochlea with MOR, DOR and KOR primers resulted in products of the predicted lengths, 564, 356 and 276 bp, respectively. Restriction digestion confirmed the identity of these products. All three receptor subtypes were identified in the cochlea and further characterized by immunocytochemistry. DOR and KOR immunoreactivity was found in inner and outer hair cells, bipolar cells of the spiral ganglion and interdental cells of the limbus. In contrast, no MOR immunoreactivity was observed in the inner and outer hair cells, and interdental cells. All three types of receptor fibers were also detected in the bipolar cells and nerve fibers within the spiral ganglion. In addition, MOR- and KOR-containing nerve fibers were observed in the limbus. These findings are the first report of the presence of all three classical opioid receptors in the inner ear and suggest that these receptors may have both presynaptic and postsynaptic roles. © 2003 Elsevier Science B.V. All rights reserved.