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Expression of AMPA receptor subunit flip/flop splice variants in the rat auditory brainstem and inferior colliculus
Author(s) -
Schmid Susanne,
Guthmann Axel,
Ruppersberg Johann Peter,
Herbert Horst
Publication year - 2000
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/1096-9861(20010205)430:2<160::aid-cne1022>3.0.co;2-3
Subject(s) - inferior colliculus , biology , ampa receptor , brainstem , neuroscience , protein subunit , flip , splice , auditory brainstem response , superior colliculus , glutamate receptor , receptor , genetics , gene , audiology , nucleus , hearing loss , medicine , apoptosis
The expression of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA) receptor subunit mRNAs and their flip/flop splice variants was evaluated in the rat auditory brainstem and inferior colliculus employing in situ hybridization with radiolabeled oligonucleotide probes. A differential expression of AMPA receptor subunits in auditory nuclei was observed. In general, neurons in all nuclei of the auditory brainstem express high levels of GluR‐C flop and GluR‐D flop mRNA, but low to very low levels of GluR‐A and GluR‐B mRNA. The strongest GluR‐C and ‐D flop expression is found in the ventral and medial part of the anteroventral cochlear nucleus, the posteroventral cochlear nucleus, and the medial and the lateral superior olive. These nuclei are part of the binaural auditory pathway which is important for sound localization in space. In contrast, neurons in the central nucleus of the inferior colliculus express high levels of GluR‐B flip but only low levels of the other AMPA receptor subunits. From our data, we conclude that neurons of nuclei involved in binaural processing exhibit a specific “auditory AMPA receptor” which consists primarily of GluR‐C flop and ‐D flop and often lacks GluR‐B subunits; this indicates fast kinetics and high Ca 2+ permeability of AMPA receptor currents. In contrast, neurons in the central nucleus of the inferior colliculus contain large amounts of GluR‐B flip subunits resulting in Ca 2+ impermeable AMPA receptors with slow kinetics. J. Comp. Neurol. 430:160–171, 2001. © 2001 Wiley‐Liss, Inc.