Olmez E, Egilmez Y, Guc M O, Ilhan M
Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Pharmacology. 1994 Jul;49(1):52-60. doi: 10.1159/000139216.
The effects of four m-cholinoceptor antagonists and d-tubocurarine on carbachol- or nicotine-induced contractions of frog rectus abdominus muscle were investigated. The n-cholinoceptor-mediated contractile responses of frog rectus abdominis muscles were inhibited competitively by d-tubocurarine whereas m-cholinoceptor antagonists inhibited them noncompetitively. Antagonistic potencies for m-cholinoceptor antagonists, assessed by pD'2 values, indicated a rank order of potency which was 4-DAMP > AF-DX 116 > atropine > pirenzepine. The antagonistic potencies of m-cholinoceptor antagonists on electrically induced twitch responses of rat phrenic nerve-diaphragm preparation were also examined. These responses were blocked by 4-DAMP, but pirenzepine had no effect. However, they were enhanced by AF-DX 116 or atropine. Inhibitory action of 4-DAMP in this preparation was suggested to be due to noncompetitive blockade of postjunctional n-cholinoceptors.
研究了四种毒蕈碱型胆碱能受体拮抗剂和筒箭毒碱对卡巴胆碱或尼古丁诱导的青蛙腹直肌收缩的影响。筒箭毒碱竞争性抑制青蛙腹直肌由烟碱型胆碱能受体介导的收缩反应，而毒蕈碱型胆碱能受体拮抗剂则非竞争性抑制该反应。通过pD'2值评估毒蕈碱型胆碱能受体拮抗剂的拮抗效力，结果显示效力顺序为4-二甲基氨基吡啶（4-DAMP）>阿非迪尼（AF-DX 116）>阿托品>哌仑西平。还检测了毒蕈碱型胆碱能受体拮抗剂对大鼠膈神经-膈肌标本电诱发抽搐反应的拮抗效力。这些反应被4-二甲基氨基吡啶阻断，但哌仑西平无作用。然而，阿非迪尼或阿托品可增强这些反应。在该标本中，4-二甲基氨基吡啶的抑制作用被认为是由于对节后烟碱型胆碱能受体的非竞争性阻断。
