奎尼丁对心脏的抗毒蕈碱作用？一项关于猫心心肌制剂的研究。
Antimuscarinic action of quinidine on the heart? A study in myocardial preparations from cat hearts.
作者信息
Nawrath H, Sack U, Zong X
出版信息
Br J Pharmacol. 1984 Jan;81(1):103-11. doi: 10.1111/j.1476-5381.1984.tb10749.x.
Quinidine exerts anticholinergic effects which have been ascribed to atropine-like properties of the drug. We have examined the effects of acetylcholine on the force of contraction in isolated heart muscle preparations from cats and compared the inhibitory effects of atropine with those of quinidine. The effects of acetylcholine were antagonized competitively in the presence of atropine. The Schild-plot yielded a straight line; the slope was not significantly different from unity. In the presence of quinidine, the concentration-response curve of acetylcholine was shifted to the right as with atropine, however, the Schild-plot yielded a regression line which was not linear; the slope was statistically different from unity. The negative inotropic response to acetylcholine in cat ventricular heart muscle (revealed in the presence of the phosphodiesterase inhibitor, papaverine) was antagonized by atropine but not influenced by quinidine. We conclude that the inhibitory action of quinidine on the effects of acetylcholine in atrial heart muscle is not merely antimuscarinic. The antagonistic effects of acetylcholine and quinidine on atrial heart muscle may also be due to the opposite effects of the drugs on potassium conductance of the myocardial cell membrane.
奎尼丁具有抗胆碱能作用，这归因于该药物类似阿托品的特性。我们研究了乙酰胆碱对猫离体心肌制剂收缩力的影响，并比较了阿托品和奎尼丁的抑制作用。在阿托品存在的情况下，乙酰胆碱的作用受到竞争性拮抗。施尔德图得到一条直线；斜率与1无显著差异。在奎尼丁存在的情况下，乙酰胆碱的浓度 - 反应曲线像在阿托品存在时一样向右移动，然而，施尔德图得到的回归线不是线性的；斜率在统计学上与1不同。阿托品可拮抗猫心室心肌对乙酰胆碱的负性肌力反应（在磷酸二酯酶抑制剂罂粟碱存在时显现），但奎尼丁对此无影响。我们得出结论，奎尼丁对心房肌中乙酰胆碱作用的抑制作用不仅仅是抗毒蕈碱作用。乙酰胆碱和奎尼丁对心房肌的拮抗作用也可能是由于这两种药物对心肌细胞膜钾电导的相反作用。
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