title: Dual effect of exogenous nitric oxide on neuronal excitability in rat substantia gelatinosa neurons.
abstract: Nitric oxide (NO) is an important signaling molecule involved in nociceptive transmission. It can induce analgesic and hyperalgesic effects in the central nervous system. In this study, patch-clamp recording was used to investigate the effect of NO on neuronal excitability in substantia gelatinosa (SG) neurons of the spinal cord. Different concentrations of sodium nitroprusside (SNP; NO donor) induced a dual effect on the excitability of neuronal membrane: 1 mM of SNP evoked membrane hyperpolarization and an outward current, whereas 10 µM induced depolarization of the membrane and an inward current. These effects were prevented by hemoglobin and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (c-PTIO) (NO scavengers), phenyl N-tert-butylnitrone (PBN; nonspecific reactive oxygen species scavenger), and through inhibition of soluble guanylyl cyclase (sGC). Pretreatment with n-ethylmaleimide (NEM; thiol-alkylating agent) also decreased effects of both 1 mM and 10 µM SNP, suggesting that these responses were mediated by direct S-nitrosylation. Charybdotoxin (CTX) and tetraethylammonium (TEA) (large-conductance Ca(2+)-activated K(+) channel blockers) and glybenclamide (ATP-sensitive K(+) channel blocker) decreased SNP-induced hyperpolarization. La(3+) (nonspecific cation channel blocker), but not Cs(+) (hyperpolarization-activated K(+) channel blocker), blocked SNP-induced membrane depolarization. In conclusion, NO dually affects neuronal excitability in a concentration-dependent manner via modification of various K(+) channels.
authors: Department of Oral Physiology, College of Dentistry, Institute of Wonkwang Biomaterial and Implant, Wonkwang University, 344-2 Shinyong Dong, Iksan 570-749, Republic of Korea.
authors: A-Reum
authors: AR
authors: Park
authors: Department of Oral Physiology, College of Dentistry, Institute of Wonkwang Biomaterial and Implant, Wonkwang University, 344-2 Shinyong Dong, Iksan 570-749, Republic of Korea.
authors: Hae In
authors: HI
authors: Lee
authors: Department of Oral Physiology, College of Dentistry, Institute of Wonkwang Biomaterial and Implant, Wonkwang University, 344-2 Shinyong Dong, Iksan 570-749, Republic of Korea.
authors: Dejidnorov
authors: D
authors: Semjid
authors: Oral Biology Research Institute, Chosun University School of Dentistry, Gwangju 501-759, Republic of Korea.
authors: Do Kyung
authors: DK
authors: Kim
authors: Department of Oral Physiology, College of Dentistry, Institute of Wonkwang Biomaterial and Implant, Wonkwang University, 344-2 Shinyong Dong, Iksan 570-749, Republic of Korea.
authors: Sang Woo
authors: SW
authors: Chun
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D016166:Free Radical Scavengers; D006162:Guanylate Cyclase / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D026361:Reactive Nitrogen Species / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects; D013376:Substantia Gelatinosa / Q000166:cytology* / Q000187:drug effects*; D013438:Sulfhydryl Compounds / Q000494:pharmacology
chemical_list: D000477:Alkylating Agents; D016166:Free Radical Scavengers; D020030:Nitric Oxide Donors; D015221:Potassium Channels; D026361:Reactive Nitrogen Species; D013438:Sulfhydryl Compounds; D009599:Nitroprusside; D009569:Nitric Oxide; D006162:Guanylate Cyclase