Mukai T
J Pharmacobiodyn. 1983 May;6(5):301-8. doi: 10.1248/bpb1978.6.301.
Effects of smooth muscle relaxants on histamine-, Ba2+- and Ca2+-induced contractions, or on electrical activities were examined in the longitudinal smooth muscle of guinea-pig ileum or taenia coli, respectively. Papaverine, D-600 and diltiazem effectively inhibited the Ca2+ responses and the tonic components of the histamine and Ba2+ responses. Especially, D-600 and diltiazem depressed the Ca2+ responses in much lower concentrations than papaverine and theophylline. In contrast, benactyzine and etomidoline were not specific antagonists against the Ca2+ responses, and they were effective inhibitory agents on the phasic responses to histamine and Ba2+. Nitroprusside failed to reduce the three types of contractions effectively. These results suggest that these seven relaxants can be divided into four types. Influence of those relaxants on spontaneously- and Ba2+-evoked electrical activities are compatible with the above differentiation. The four types of relaxants used in this study seem to exert their actions on smooth muscle in different way. Nitroprusside, however, is not a potent relaxant against contractions of the intestinal smooth muscles.
分别在豚鼠回肠或结肠带的纵行平滑肌中研究了平滑肌松弛剂对组胺、Ba2+和Ca2+诱导的收缩或电活动的影响。罂粟碱、D - 600和地尔硫卓有效抑制了Ca2+反应以及组胺和Ba2+反应的强直成分。特别是，D - 600和地尔硫卓在比罂粟碱和茶碱低得多的浓度下就能抑制Ca2+反应。相比之下，苯那辛和依托咪定不是针对Ca2+反应的特异性拮抗剂，它们是组胺和Ba2+相位反应的有效抑制剂。硝普钠不能有效降低这三种类型的收缩。这些结果表明这七种松弛剂可分为四类。这些松弛剂对自发和Ba2+诱发的电活动的影响与上述分类一致。本研究中使用的四种类型的松弛剂似乎以不同方式作用于平滑肌。然而，硝普钠不是肠道平滑肌收缩的有效松弛剂。
