title: Inner hair cells of mice express the glutamine transporter SAT1.
abstract: Glutamate has been implicated in signal transmission between inner hair cells and afferent fibers of the organ of Corti. The inner hair cells are enriched in glutamate and the postsynaptic membranes express AMPA glutamate receptors. However, it is not known whether inner hair cells contain a mechanism for glutamate replenishment. Such a mechanism must be in place to sustain glutamate neurotransmission. Here we provide RT-PCR and immunofluorescence data indicating that system A transporter 1 (SLC38A1), which is associated with neuronal glutamine transport and synthesis of the neurotransmitters GABA and glutamate in CNS, is expressed in inner hair cells. It was previously shown that inner hair cells contain glutaminase that converts glutamine to glutamate. Thus, our finding that inner hair cells express a glutamine transporter and the key glutamine metabolizing enzyme glutaminase, provides a mechanism for glutamate replenishment and bolsters the idea that glutamate serves as a transmitter in the peripheral synapse of the auditory system.
authors: Centre for Molecular Biology and Neuroscience, Institute of Basic Medical Sciences, University of Oslo, Blindern, Oslo, Norway.
authors: Tomohiro
authors: T
authors: Oguchi
authors: Nobuyoshi
authors: N
authors: Suzuki
authors: Shigenari
authors: S
authors: Hashimoto
authors: Gauhar Ayub
authors: GA
authors: Chaudhry
authors: Farrukh Abbas
authors: FA
authors: Chaudhry
authors: Shin-Ichi
authors: S
authors: Usami
authors: Ole Petter
authors: OP
authors: Ottersen
mesh_terms: D026924:Amino Acid Transport System A / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D026922:Amino Acid Transport Systems, Acidic / Q000032:analysis; D000818:Animals; D018698:Glutamic Acid / Q000378:metabolism*; D006199:Hair Cells, Auditory, Inner / Q000737:chemistry* / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050598:Vesicular Glutamate Transport Protein 1 / Q000032:analysis; D050599:Vesicular Glutamate Transport Protein 2 / Q000032:analysis
chemical_list: D026924:Amino Acid Transport System A; D026922:Amino Acid Transport Systems, Acidic; D018698:Glutamic Acid; D012333:RNA, Messenger; D050598:Vesicular Glutamate Transport Protein 1; D050599:Vesicular Glutamate Transport Protein 2; C493477:Slc17a6 protein, mouse; C493465:Slc17a7 protein, mouse; C432411:Slc38a1 protein, mouse; C504941:Slc17a8 protein, mouse