Vegesna R V, Diamond J
Life Sci. 1986 Jul 28;39(4):303-11. doi: 10.1016/0024-3205(86)90648-x.
The role of cyclic AMP in the control of vascular smooth muscle tone was studied by monitoring the effects of prostaglandin E1 (PGE1), isoproterenol and forskolin on cyclic AMP levels and tension in rabbit aortic rings. PGE1, isoproterenol and forskolin all increased cyclic AMP levels in rabbit aortic rings. Isoproterenol and forskolin relaxed phenylephrine-contracted aortic rings, but PGE1 contracted the rings in the presence or absence of phenylephrine. Isoproterenol relaxed these PGE1-contracted aortic rings without further change in total cyclic AMP levels, which were already elevated by the PGE1 alone. Pretreatment with forskolin potentiated the effects of PGE1 on cyclic AMP levels. PGE1 caused contractions in muscles partially relaxed by forskolin, even though very large increases in cyclic AMP levels (30 fold) were produced by PGE1 in the presence of forskolin. Isoproterenol was able to relax these forskolin-treated, PGE1-contracted muscles with no further increase in cyclic AMP levels. Thus, there does not appear to be a good correlation between total tissue levels of cyclic AMP and tension in these experiments. Our results suggest that, if cyclic AMP is responsible for relaxation of smooth muscle, some form of functional compartmentalization of cyclic AMP must exist in this tissue.
通过监测前列腺素E1（PGE1）、异丙肾上腺素和福斯高林对兔主动脉环中环磷酸腺苷（cAMP）水平和张力的影响，研究了cAMP在控制血管平滑肌张力中的作用。PGE1、异丙肾上腺素和福斯高林均可提高兔主动脉环中的cAMP水平。异丙肾上腺素和福斯高林可使苯肾上腺素收缩的主动脉环舒张，但无论有无苯肾上腺素存在，PGE1均可使主动脉环收缩。异丙肾上腺素可使这些PGE1收缩的主动脉环舒张，而总cAMP水平无进一步变化，单独使用PGE1时总cAMP水平已升高。用福斯高林预处理可增强PGE1对cAMP水平的影响。尽管在福斯高林存在的情况下，PGE1可使cAMP水平大幅升高（30倍），但PGE1仍可使部分由福斯高林舒张的肌肉收缩。异丙肾上腺素能够使这些经福斯高林处理、PGE1收缩的肌肉舒张，而cAMP水平无进一步升高。因此，在这些实验中，cAMP的总组织水平与张力之间似乎没有良好的相关性。我们的结果表明，如果cAMP负责平滑肌舒张，那么该组织中必定存在某种形式的cAMP功能区室化。
