Co-expression of NMDA and AMPA/kainate receptor mRNAs in cochlear neurones.
The co-expression of NMDAR-1 and GluR1-4 mRNAs in spiral ganglions of rat and guinea-pig cochleas was checked using a non-radioactive in situ hybridization technique. NMDAR-1, GluR2 and GluR3 mRNAs were expressed in the large neurones (type I) of the ganglion which innervate inner hair cells (IHCs), a sensory cell type likely to use an excitatory amino acid as a neurotransmitter. The labelling was very intense with the GluR2 and GluR3 oligoprobes while it remained moderate with the NMDAR-1 oligoprobe. This is consistent with the predominant implication of AMPA/kainate receptors in the physiological and early pathophysiological aspects of the IHC neurotransmission. Spiral ganglion neurones did not express GluR1 and GluR4 mRNAs, but a glial expression of GluR4 mRNAs was observed.
Safieddine
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INSERM U.254, CHU Hôpital St. Charles, Montpellier, France.
Eybalin
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D000818:Animals; D003051:Cochlea / Q000166:cytology / Q000378:metabolism*; D005724:Ganglia / Q000166:cytology / Q000378:metabolism; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000378:metabolism; D017403:In Situ Hybridization; D066298:In Vitro Techniques; D009474:Neurons / Q000378:metabolism*; D009841:Oligonucleotides; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D018091:Receptors, AMPA; D017470:Receptors, Glutamate / Q000096:biosynthesis*; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis*
D009841:Oligonucleotides; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate