title: Characterization of dental nociceptive neurons.
abstract: Selective blockade of nociceptive neurons can be achieved by the delivery of permanently charged sodium channel blockers through the pores of nociceptive ion channels. To assess the feasibility of this application in the dental area, we investigated the electrophysiological and neurochemical characteristics of nociceptive dental primary afferent (DPA) neurons. DPA neurons were identified within trigeminal ganglia labeling with a retrograde fluorescent dye applied to the upper molars of adult rats. Electrophysiological studies revealed that the majority of dental primary afferent neurons showed characteristics of nociceptive neurons, such as sensitivity to capsaicin and the presence of a hump in action potential. Immunohistochemical analysis revealed a large proportion of DPA neurons to be IB(4)-positive and to express TRPV1 and P2X(3). Single-cell RT-PCR revealed mRNA expression of various nociceptive channels, including the temperature-sensitive TRPV1, TRPA1, TRPM8 channels, the extracellular ATP receptor channels P2X(2) and P2X(3), as well as the nociceptor-specific sodium channel, Na(V)1.8. In conclusion, DPA neurons have the electrophysiological characteristics of nociceptors and express several nociceptor-specific ion channels. Analysis of these data may assist in the search for a new route of entry for the delivery of membrane-impermeant local anesthetics.
authors.affiliation: National Research Laboratory for Pain, Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, 28 Yeongeon-Dong, Jongno-Gu, Seoul 110-749, Republic of Korea.
authors.forename: H Y
authors.initials: HY
authors.lastname: Kim
authors.forename: G
authors.initials: G
authors.lastname: Chung
authors.forename: H J
authors.initials: HJ
authors.lastname: Jo
authors.forename: Y S
authors.initials: YS
authors.lastname: Kim
authors.forename: Y C
authors.initials: YC
authors.lastname: Bae
authors.forename: S J
authors.initials: SJ
authors.lastname: Jung
authors.forename: J-S
authors.initials: JS
authors.lastname: Kim
authors.forename: S B
authors.initials: SB
authors.lastname: Oh
mesh_terms: D000200:Action Potentials; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D008012:Lidocaine / Q000031:analogs & derivatives / Q000494:pharmacology; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009619:Nociceptors / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D058476:Receptors, Purinergic P2X2 / Q000096:biosynthesis; D058477:Receptors, Purinergic P2X3 / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018689:Sensory System Agents / Q000494:pharmacology; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D015222:Sodium Channels / Q000096:biosynthesis*; D014070:Tooth / Q000294:innervation*; D014098:Toothache / Q000188:drug therapy; D050051:Transient Receptor Potential Channels / Q000096:biosynthesis*; D012668:Trigeminal Ganglion / Q000378:metabolism
chemical_list: D000779:Anesthetics, Local; D005456:Fluorescent Dyes; D062559:NAV1.8 Voltage-Gated Sodium Channel; D058476:Receptors, Purinergic P2X2; D058477:Receptors, Purinergic P2X3; C568319:Scn10a protein, rat; D018689:Sensory System Agents; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D050051:Transient Receptor Potential Channels; C012647:QX-314; D008012:Lidocaine; D002211:Capsaicin