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Role of copper in the relaxant action of S ‐nitrosothiols in the rat anococcygeus muscle
Author(s) -
Ng Chi Wai,
NajbarKaszkiel Alicja T,
Li Chun Guang
Publication year - 2003
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.2003.03845.x
Subject(s) - chemistry , snap , s nitrosoglutathione , sodium nitroprusside , nitric oxide , muscle relaxant , guanethidine , chelation , pharmacology , endocrinology , stimulation , biophysics , medicine , biochemistry , glutathione , inorganic chemistry , enzyme , computer graphics (images) , organic chemistry , computer science , biology
Summary 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 µmol/L), SNAP (0.001–10 µmol/L), SNP (0.001–1 µmol/L) and NO· (0.5–5 µmol/L) and electrical field stimulation (EFS; 1–5 Hz, 10 s) of nitrergic nerves in preparations precontracted with guanethidine (10–30 µmol/L) and clonidine (0.01–0.3 µmol/L) produced concentration‐dependent relaxations. 3. The Cu[I] chelator neocuproine (10–30 µmol/L) produced concentration‐dependent inhibitions of the relaxations to GSNO and SNAP. At 30 µmol/L, neocuprinone had no effect on relaxations to SNP (0.001–1 µmol/L), NO· (0.5–5 µmol/L) or EFS (1–5 Hz, 10 s). 4. The Cu[II] chelator cuprizone (30 µmol/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.