title: Subunit-specific P2X-receptor expression defines chemosensory properties of trigeminal neurons.
abstract: The facial innervation pattern of trigeminal nerve fibres comprises the innervation of the nasal epithelium, where free trigeminal nerve endings contribute to detection and discrimination of chemical stimuli including odourants. The signal transduction mechanisms in sensory nerve endings underlying perception of chemical stimuli remain widely uncovered. Here, we characterized trigeminal ATP-activated P2X receptors in cultured rat trigeminal neurons and investigated their role in chemoperception. We identified a new subpopulation of neurons lacking typical nociceptive characteristics and expressing homomeric P2X(2) receptors. Using a certain group of chemicals known as trigeminal stimuli we found no direct activation of trigeminal neurons, but a modulation of P2X(2) receptor mediated currents. In contrast, P2X(3) receptor mediated currents of nociceptive trigeminal neurons remained unaffected by the tested chemicals. Therefore, we assume a functional role for the newly identified subpopulation in chemodetection of certain trigeminal stimuli.
authors.affiliation: Lehrstuhl fuer Zellphysiologie, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Spehr
authors.forename: Marc
authors.initials: M
authors.lastname: Spehr
authors.forename: Hanns
authors.initials: H
authors.lastname: Hatt
authors.forename: Christian H
authors.initials: CH
authors.lastname: Wetzel
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001547:Benzaldehydes / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry; D003952:Diagnostic Imaging / Q000379:methods; D015226:Dinucleoside Phosphates / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007668:Kidney; D008164:Luminescent Proteins / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D016501:Neurites / Q000187:drug effects; D009474:Neurons / Q000145:classification / Q000378:metabolism*; D018034:Olfactory Receptor Neurons / Q000502:physiology; D009930:Organic Chemicals / Q000494:pharmacology; D018408:Patch-Clamp Techniques / Q000379:methods; D011188:Potassium / Q000494:pharmacology; D021122:Protein Subunits / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058476:Receptors, Purinergic P2X2; D058477:Receptors, Purinergic P2X3; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013268:Stimulation, Chemical; D014162:Transfection / Q000379:methods; D014227:Triazines / Q000494:pharmacology; D012668:Trigeminal Ganglion / Q000166:cytology*
chemical_list: D001547:Benzaldehydes; D018076:DNA, Complementary; D015226:Dinucleoside Phosphates; D004791:Enzyme Inhibitors; D008164:Luminescent Proteins; D009930:Organic Chemicals; C546401:P2RX2 protein, human; C546407:P2RX3 protein, human; C546403:P2rx2 protein, rat; C546410:P2rx3 protein, rat; D021122:Protein Subunits; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D058477:Receptors, Purinergic P2X3; D014227:Triazines; C109479:diinosine pentaphosphate; D049452:Green Fluorescent Proteins; D005576:Colforsin; C012842:Cibacron Blue F 3GA; D000255:Adenosine Triphosphate; D011188:Potassium; D002118:Calcium; C032175:benzaldehyde