title: Contribution of persistent sodium currents to the excitability of tonic firing substantia gelatinosa neurons of the rat.
abstract: The roles of persistent Na(+) currents (INaP) in intrinsic membrane properties were examined in rat substantia gelatinosa (SG) neurons of the trigeminal subnucleus caudalis using a conventional whole-cell patch clamp technique. In a voltage-clamp mode, riluzole inhibited the slow voltage ramp-induced INaP but had little effect on the peak amplitude of transient Na(+) currents in SG neurons. In a current-clamp mode, most SG neurons exhibited spontaneous action potentials and tonic firing pattern. Riluzole reduced both spontaneous and elicited action potentials in a concentration-dependent manner. The present results suggest that the riluzole-sensitive INaP plays an important role in the excitability of SG neurons and are thus, likely to contribute to the modulation of nociceptive transmission from the orofacial tissues.
authors.affiliation: Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea.
authors.forename: Jin-Hwa
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea.
authors.forename: In-Sun
authors.initials: IS
authors.lastname: Choi
authors.affiliation: Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea.
authors.forename: Seok-Ho
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu 700-412, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu 700-412, Republic of Korea.
authors.forename: Maan-Gee
authors.initials: MG
authors.lastname: Lee
authors.affiliation: Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu 700-412, Republic of Korea. Electronic address: jis7619@mail.knu.ac.kr.
authors.forename: Il-Sung
authors.initials: IS
authors.lastname: Jang
mesh_terms: D000200:Action Potentials; D000818:Animals; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017207:Rats, Sprague-Dawley; D019782:Riluzole / Q000494:pharmacology; D013376:Substantia Gelatinosa / Q000502:physiology*; D061566:Voltage-Gated Sodium Channels / Q000502:physiology*
chemical_list: D061566:Voltage-Gated Sodium Channels; D019782:Riluzole
keywords: I(NaP); Patch clamp; Substantia gelatinosa; Trigeminal subnucleus caudalis; Voltage-gated Na(+) channels