Gibson A, Carvajal A
Department of Pharmacology, King's College London, Chelsea Campus, UK.
J Pharm Pharmacol. 1988 Feb;40(2):137-9. doi: 10.1111/j.2042-7158.1988.tb05200.x.
Ergometrine (0.02-5 microM) produced concentration-related contractions of the mouse anococcygeus muscle, which were unaffected by cocaine (2 microM) or by pretreatment of mice with 6-hydroxydopamine. Contractions were reduced by alpha-adrenoceptor antagonists; the rank order of potency was prazosin greater than phentolamine greater than yohimbine. With phenoxybenzamine as antagonist, the estimated dissociation constant (KD) for ergometrine was 0.41 microM. It is concluded that ergometrine causes direct activation of postsynaptic alpha 1-adrenoceptors, and it is suggested that it acts on the same subtype of the receptor as imidazoline agonists.
麦角新碱（0.02 - 5微摩尔）可引起小鼠肛门尾骨肌浓度依赖性收缩，这种收缩不受可卡因（2微摩尔）或用6 - 羟基多巴胺预处理小鼠的影响。α - 肾上腺素能受体拮抗剂可减弱收缩；效价顺序为哌唑嗪＞酚妥拉明＞育亨宾。以酚苄明作为拮抗剂时，麦角新碱的估计解离常数（KD）为0.41微摩尔。结论是麦角新碱可直接激活突触后α1 - 肾上腺素能受体，提示其作用于与咪唑啉激动剂相同亚型的受体。
