title: P2X2 receptor subunit expression in a subpopulation of cochlear type I spiral ganglion neurones.
abstract: Spiral ganglion neurones in rat cochlea express three different isoforms of the P2X2 receptor subunit which assemble into ATP-gated ion channels. Two of these P2X2R subunit isoforms have previously been detected in other auditory tissues. The third isoform (designated P2X2-3R) has not been described. This isoform lacks 39 bp immediately prior to the stop codon, corresponding to a 13 amino acid deletion of the extreme C-terminus domain. Using direct in situ RT-PCR, expression of P2X2R mRNA was confined to a subpopulation of type I spiral ganglion neurones. This study supports a role for extracellular ATP as a neurotransmitter for a discrete population of auditory neurones where variation in P2X2R isoform assembly may confer functional heterogeneity, including enhanced desensitization.
authors.affiliation: Department of Physiology, Faculty of Medicine and Health Science, University of Auckland, New Zealand.
authors.forename: S G
authors.initials: SG
authors.lastname: Salih
authors.forename: G D
authors.initials: GD
authors.lastname: Housley
authors.forename: L D
authors.initials: LD
authors.lastname: Burton
authors.forename: D
authors.initials: D
authors.lastname: Greenwood
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003051:Cochlea / Q000294:innervation / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D008297:Male; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000096:biosynthesis*; D058476:Receptors, Purinergic P2X2; D013136:Spiral Ganglion / Q000166:cytology / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: D009479:Neuropeptides; C546403:P2rx2 protein, rat; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D000255:Adenosine Triphosphate; D004247:DNA