Cortijo J, Foster R W, Small R C
J Pharm Pharmacol. 1987 Apr;39(4):283-9. doi: 10.1111/j.2042-7158.1987.tb06267.x.
In taenia preparations, depolarized by a K+-rich medium, Ca2+ caused contraction and cinnarizine (0.4-100 microM), trifluoperazine (2-100 microM) and verapamil (0.02-10 microM) caused concentration-dependent antagonism of Ca2+, displacing the Ca2+ log concentration-effect curve to the right and depressing the maximal response. Equieffective (IC75) antispasmogenic concentrations were selected. The antispasmogenic effects of verapamil were readily offset by removing the drug from the bathing fluid but those of the other drugs were not. The calcium antagonists (antispasmogenic IC75) were then tested for spasmolytic activity in tissues generating tension in response to the EC80 of Ca2+. Verapamil was more effective in producing spasmolysis than cinnarazine or trifluoperazine. In skinned taenia preparations, verapamil (100 microM) did not inhibit Ca2+-induced contractions. High concentrations of cinnarizine (100 microM) and trifluoperazine (100 microM) inhibited Ca2+-induced activation of the contractile proteins. However, antispasmogenic IC75s from intact taenia were not able to produce this effect on skinned preparations. It is concluded that there are differences between calcium antagonists. The action of verapamil on intact taenia is mainly exerted on the plasma membrane. Cinnarizine and trifluoperazine act both on the plasma membrane and upon the intracellular contractile machinery.
在富含钾离子的培养基使绦虫标本去极化后，钙离子会引起收缩，而桂利嗪（0.4 - 100微摩尔）、三氟拉嗪（2 - 100微摩尔）和维拉帕米（0.02 - 10微摩尔）会引起钙离子浓度依赖性拮抗作用，使钙离子对数浓度 - 效应曲线右移并降低最大反应。选择等效（IC75）抗痉挛浓度。将维拉帕米从浴液中去除后，其抗痉挛作用很容易被抵消，但其他药物的抗痉挛作用则不会。然后在对钙离子EC80产生张力的组织中测试钙拮抗剂（抗痉挛IC75）的解痉活性。维拉帕米在产生解痉作用方面比桂利嗪或三氟拉嗪更有效。在去表皮绦虫标本中，维拉帕米（100微摩尔）不抑制钙离子诱导的收缩。高浓度的桂利嗪（100微摩尔）和三氟拉嗪（100微摩尔）抑制钙离子诱导的收缩蛋白激活。然而，完整绦虫的抗痉挛IC75对去表皮标本无法产生这种作用。结论是钙拮抗剂之间存在差异。维拉帕米对完整绦虫的作用主要施加于质膜。桂利嗪和三氟拉嗪既作用于质膜，也作用于细胞内收缩机制。
