Demesy-Waeldele F, Stoclet J C
Eur J Pharmacol. 1975 Apr;31(2):185-94. doi: 10.1016/0014-2999(75)90039-4.
The spasmolytic effects of papaverine and dibutyryl cyclic AMP (db-cAMP) were compared on isometric contractile responses induced by addition of increasing amounts of external calcium to K+-depolarized or noradrenaline-stimulated rat aorta strips. Papaverine at a concentration active on depolarized strips (3 times 10(-5) moles/1) reduced the maximal contraction (Emax) elicited by Ca2+ in these preparations, while db-cAMP did not. Contrary to what was observed on depolarized aortae, the degree of inhibition of noradrenaline-stimulated strips did not decrease with increasing extracellular calcium concentration (Ca)e. Both db-cAMP and papaverine at a concentration which did not depress Emax (5 times 10(-6) moles/1) potentiated the relaxing effect of high (Ca)e on contractions elicited by noradrenaline. In conclusion, cyclic AMP is probably implicated in the mode of action of papaverine on the noradrenaline-stimulated rat aorta. At a concentration active on depolarized strips, papaverine is also able to impair contractility directly.
在向K⁺去极化或去甲肾上腺素刺激的大鼠主动脉条中添加递增剂量的细胞外钙所诱导的等长收缩反应上，比较了罂粟碱和二丁酰环磷腺苷（db - cAMP）的解痉作用。在去极化条上具有活性的浓度（3×10⁻⁵摩尔/升）的罂粟碱降低了这些制剂中Ca²⁺引发的最大收缩（Emax），而db - cAMP则没有。与在去极化主动脉上观察到的情况相反，去甲肾上腺素刺激条的抑制程度并未随着细胞外钙浓度（Ca）e的增加而降低。在不降低Emax的浓度（5×10⁻⁶摩尔/升）下，db - cAMP和罂粟碱均增强了高（Ca）e对去甲肾上腺素引发的收缩的舒张作用。总之，环磷腺苷可能参与了罂粟碱对去甲肾上腺素刺激的大鼠主动脉的作用方式。在对去极化条具有活性的浓度下，罂粟碱也能够直接损害收缩性。
