title: Role of copper in the relaxant action of S-nitrosothiols in the rat anococcygeus muscle.
abstract: 1. The effects of copper chelators were investigated on the relaxant actions of the S-nitrosothiols S-nitrosoglutathione (GSNO) and S-nitroso-N-acetyl-d,l-penicillamine (SNAP), the non-S-nitrosothiol nitric oxide (NO) donor sodium nitroprusside (SNP), free radical NO (NO.) and the nitrergic neurotransmitter in rat isolated anococcygeus muscle. 2. Cumulative additions of GSNO (0.01-100 micro mol/L), SNAP (0.001-10 micro mol/L), SNP (0.001-1 micro mol/L) and NO. (0.5-5 micro mol/L) and electrical field stimulation (EFS; 1-5 Hz, 10 s) of nitrergic nerves in preparations precontracted with guanethidine (10-30 micro mol/L) and clonidine (0.01-0.3 micro mol/L) produced concentration-dependent relaxations. 3. The Cu[I] chelator neocuproine (10-30 micro mol/L) produced concentration-dependent inhibitions of the relaxations to GSNO and SNAP. At 30 micro mol/L, neocuprinone had no effect on relaxations to SNP (0.001-1 micro mol/L), NO. (0.5-5 micro mol/L) or EFS (1-5 Hz, 10 s). 4. The Cu[II] chelator cuprizone (30 micro mol/L) slightly and significantly enhanced relaxations to GSNO and NO., but had no effect on relaxations to SNAP, SNP or EFS. 5. In conclusion, the results indicate that Cu[I], but not Cu[II], may be involved in the relaxant actions of GSNO and SNAP in the rat anococcygeus muscle.
authors.affiliation: School of Medical Sciences, Division of Biosciences, RMIT University, Melbourne, Victoria, Australia.
authors.forename: Chi Wai
authors.initials: CW
authors.lastname: Ng
authors.forename: Alicja T
authors.initials: AT
authors.lastname: Najbar-Kaszkiel
authors.forename: Chun Guang
authors.initials: CG
authors.lastname: Li
mesh_terms: D001003:Anal Canal / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D002614:Chelating Agents / Q000494:pharmacology; D003300:Copper / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects* / Q000502:physiology; D026602:Nitrergic Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D026403:S-Nitrosothiols / Q000494:pharmacology*; D012445:Sacrococcygeal Region / Q000502:physiology
chemical_list: D002614:Chelating Agents; D026403:S-Nitrosothiols; D003300:Copper