title: Stable expression and characterization of human PN1 and PN3 sodium channels.
abstract: Nociceptive transduction in inflammatory and neuropathic pain involves peripherally expressed voltage-gated sodium channels, such as tetrodotoxin (TTX)-sensitive PN1 and TTX-resistant PN3. We generated recombinant cell lines stably expressing the human PN1 and PN3 sodium channels in Chinese hamster ovary (CHO) cells using inducible expression vectors. The PN1 and PN3 cDNAs were isolated from human adrenal gland and heart poly(A)+ RNAs, respectively. The recombinant human PN1 currents exhibited rapid activation and inactivation kinetics and were blocked by TTX with a half-maximal inhibitory concentration (IC50) of 32.6 nM. The human PN3 channel expressed in stable transfectants showed TTX-resistant inward currents with slow inactivation kinetics. The IC50 value for TTX was 73.3 microM. The voltage-dependence of activation of the PN3 channel was shifted to the depolarizing direction, compared to that of the PN1 channel. Lidocaine and mexiletine exhibited tonic and use-dependent block of PN1 and PN3 channels. The PN1 channel was more susceptible to inhibition by mexiletine than PN3. These results suggest that stable transfectants expressing the human PN1 and PN3 sodium channels will be useful tools to define subtype selectivity for sodium channel blockers.
authors.affiliation: Department of Molecular and Cellular Biology, Nippon Boehringer Ingelheim Co., Ltd., Kawanishi Pharma Research Institute, Yato, Kawanishi, Japan.
authors.forename: Isamu
authors.initials: I
authors.lastname: Akiba
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Seki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Mori
authors.forename: Masaki
authors.initials: M
authors.lastname: Iizuka
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Nishimura
authors.forename: Sachie
authors.initials: S
authors.lastname: Sasaki
authors.forename: Keiji
authors.initials: K
authors.lastname: Imoto
authors.forename: Edward L
authors.initials: EL
authors.lastname: Barsoumian
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004594:Electrophysiology; D006801:Humans; D008012:Lidocaine / Q000494:pharmacology; D008801:Mexiletine / Q000494:pharmacology; D062556:NAV1.7 Voltage-Gated Sodium Channel; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
chemical_list: D000779:Anesthetics, Local; D018076:DNA, Complementary; D062556:NAV1.7 Voltage-Gated Sodium Channel; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009479:Neuropeptides; C568317:SCN10A protein, human; C486866:SCN9A protein, human; C568319:Scn10a protein, rat; C503480:Scn9a protein, rat; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D008801:Mexiletine; D008012:Lidocaine