Zonta F, D'Agostino G, Grana E
Pharmacol Res Commun. 1986 Nov;18(11):1031-41. doi: 10.1016/0031-6989(86)90020-2.
The effects of papaverine and verapamil on Ca2+ - and epinephrine evoked responses were investigated on spontaneously beating atria of the guinea-pig. Papaverine showed a non competitive antagonism against epinephrine but was ineffective against Ca2+; verapamil antagonized both the action of epinephrine and Ca2+ in a different manner but at the same concentrations. The pharmacological prerequisite to classify an anti-Ca2+ substance as a blocker of Ca2+ entry (that is the ability to selectively antagonize the Ca2+ -induced contraction relative to those of norepinephrine in vascular smooth muscle) was not met by the results obtained in the cardiac tissue. The behaviors of verapamil and papaverine with regard to Ca2+ response suggest another criterion for classifying a substance as a Ca2+ entry blocker based on the ability or inability to inhibit the response of the atrial preparation to Ca2+.
研究了罂粟碱和维拉帕米对豚鼠自发性搏动心房中钙和肾上腺素诱发反应的影响。罂粟碱对肾上腺素表现出非竞争性拮抗作用，但对钙无效；维拉帕米以不同方式但在相同浓度下拮抗肾上腺素和钙的作用。在心脏组织中获得的结果未满足将抗钙物质分类为钙通道阻滞剂的药理学前提条件（即相对于血管平滑肌中去甲肾上腺素诱导的收缩，能够选择性拮抗钙诱导的收缩）。维拉帕米和罂粟碱对钙反应的行为表明，基于能否抑制心房标本对钙的反应，存在另一种将物质分类为钙通道阻滞剂的标准。
