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Post‐receptor pathway of the ATP‐induced relaxation in smooth muscle of the mouse vas deferens
Author(s) -
Gailly Ph.,
Boland B.,
Paques C.,
Himpens B.,
Casteels R.,
Gillis J.M.
Publication year - 1993
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1993.tb13812.x
Subject(s) - vas deferens , isoprenaline , endocrinology , agonist , medicine , chemistry , adenylyl cyclase , adenosine , muscle relaxation , adenosine triphosphate , muscle contraction , forskolin , receptor , biology , biochemistry , stimulation
1 The post‐receptor pathway of the ATP relaxant effect in K + ‐precontracted vas deferens smooth muscle (VD) was examined. 2 The relaxation to ATP was not antagonized either by 10 μ m methylene blue, a cyclic GMP inhibitor, by 10 μ m indomethacin, an inhibitor of prostaglandin synthesis or by 100 μ m N G ‐nitro‐ l ‐arginine, an inhibitor of NO production. 3 The Rp‐diastereomer of adenosine 3′:5′‐cyclic monophosphorothioate (Rp‐cAMPS) 200 μ m , a competitive inhibitor of cyclic AMP significantly diminished the relaxant response to ATP. 4 Isoprenaline 10 μ m , a β‐adrenoceptor agonist, produced a sustained relaxation, inhibited by Rp‐cAMPS, without a significant change in [Ca 2+ ] i , thereby mimicking the ATP‐induced relaxant effect. 5 The level of the phosphorylated myosin light chain in the precontracted VD was significantly lowered by 1000 μ m ATP. 6 ATP (1000 μ m ) and isoprenaline (10 μ m ) produced the same increase (+ 50%) of [cyclic AMP] when applied to a resting VD. 7 The effect of simultaneous increases of [Ca 2+ ] i and of [cyclic AMP] produced by externally applied ATP are discussed. 8 These results suggest that ATP‐induced relaxation in K + ‐precontracted VD is mediated by the activation of adenylyl cyclase.