title: TRPC1 and metabotropic glutamate receptor expression in rat auditory midbrain neurons.
abstract: Canonical transient receptor potential (TRPC) channels are plasma membrane cation channels included in the TRP superfamily. TRPC1 is expressed widely in the central nervous system and is linked to group I metabotropic glutamate receptors (mGluRs). In the auditory brainstem, TRPC1 expression has never been described, although group I mGluRs are present. In the central nucleus of the inferior colliculus (CIC), activation of group I mGluRs induces an extracellular Ca(2+) influx after store depletion. Therefore, this study examines whether TRPC1 is expressed in this region to establish a correlation with mGluRs. By quantitative reverse transcription-polymerase chain reaction and Western blotting, this study assesses the presence of TRPC1 along with both group I mGluR subtypes mGluR1 and mGluR5 in the rat inferior colliculus (IC). All these molecules present a robust expression in the IC. By confocal double immunofluorescence, this study also demonstrates that TRPC1 colocalizes with parvalbumin, a CIC neuronal marker, in many cells. Conversely, TRPC1 was lacking in glial fibrillary acidic protein-positive glial cells. All the glutamate acid decarboxylase 67 (GAD67)-immunoreactive neurons and many GAD67-negative neurons were positive to TRPC1, which indicates the presence of TRPC1 in γ-aminobutyric acid (GABA)-ergic and non-GABAeregic neurons. With regard to subcellular distribution, TRPC1 was absent in synaptophysin-immunoreactive axonic terminals but colocalized with postsynaptic marker microtubule-associated protein 2 in cell bodies and dendrites. TRPC1 totally overlapped group I mGluRs, which supports the involvement of TRPC1 in the mGluR pathway and, likely, in auditory signal processing at the midbrain level. .
authors: Instituto de Investigación en Discapacidades Neurológicas/Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.
authors: Maria Ll
authors: ML
authors: Valero
authors: Elena
authors: E
authors: Caminos
authors: Jose M
authors: JM
authors: Juiz
authors: Juan R
authors: JR
authors: Martinez-Galan
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D007245:Inferior Colliculi / Q000166:cytology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013347:Subcellular Fractions / Q000378:metabolism; D016708:Synaptophysin / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D010320:Parvalbumins; D012333:RNA, Messenger; D018094:Receptors, Metabotropic Glutamate; D016708:Synaptophysin; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; D002118:Calcium
keywords: TRPC1; auditory system; inferior colliculus; metabotropic glutamate receptors