title: P2X3 is expressed by DRG neurons that terminate in inner lamina II.
abstract: The P2X3 receptor subunit, a member of the P2X family of ATP-gated ion channels, is almost exclusively localized in sensory neurons. In the present study, we sought to gain insight into the role of P2X3 and P2X3-containing neurons in sensory transmission, using immunohistochemical approaches. In rat dorsal root ganglia (DRG), P2X3-immunoreactivity (-ir) was observed in small- and medium-sized neurons. Approximately 40% of DRG neuronal profiles in normal rats contained P2X3-ir. In rats that had received neonatal capsaicin treatment, the number of P2X3-positive neurons was decreased by approximately 70%. Analysis of the colocalization of P2X3-ir with cytochemical markers of DRG neurons indicated that approximately 94% of the P2X3-positive neuronal profiles were labelled by isolectin B4 from Bandeiraea simplicifolia, while only 3% contained substance P-ir, and 7% contained somatostatin-ir. In dorsal horn of rat spinal cord, P2X3-ir was observed in the inner portion of lamina II and was reduced subsequent to dorsal rhizotomy, as well as subsequent to neonatal capsaicin treatment. Finally, P2X3-ir accumulated proximal to the site of sciatic nerve ligation, and was seen in nerve fibres in skin and corneal epithelium. In summary, our results suggest that P2X3 is expressed by a functionally heterogeneous population of BSI-B4-binding sensory neurons, and is transported into both central and peripheral processes of these neurons.
authors.affiliation: Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis 55455, USA.
authors.forename: L
authors.initials: L
authors.lastname: Vulchanova
authors.forename: M S
authors.initials: MS
authors.lastname: Riedl
authors.forename: S J
authors.initials: SJ
authors.lastname: Shuster
authors.forename: L S
authors.initials: LS
authors.lastname: Stone
authors.forename: K M
authors.initials: KM
authors.lastname: Hargreaves
authors.forename: G
authors.initials: G
authors.lastname: Buell
authors.forename: A
authors.initials: A
authors.lastname: Surprenant
authors.forename: R A
authors.initials: RA
authors.lastname: North
authors.forename: R
authors.initials: R
authors.lastname: Elde
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002211:Capsaicin / Q000633:toxicity; D019573:Epithelium, Corneal / Q000294:innervation; D005455:Fluorescent Antibody Technique; D008297:Male; D018613:Microscopy, Confocal; D009474:Neurons / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058477:Receptors, Purinergic P2X3; D012584:Sciatic Nerve / Q000378:metabolism; D012867:Skin / Q000294:innervation; D013116:Spinal Cord / Q000378:metabolism*; D013126:Spinal Nerve Roots / Q000166:cytology / Q000378:metabolism*
chemical_list: C546410:P2rx3 protein, rat; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; D002211:Capsaicin