Nakamura H, Kiso Y, Motoyoshi S, Yoshida N, Ishii K, Yokoyama Y, Kadokawa T, Shimizu M
Eur J Pharmacol. 1982 Nov 19;85(2):133-42. doi: 10.1016/0014-2999(82)90458-7.
The pharmacological actions of Tyr-D-Met(O)-Gly-MePheol (syndyphalin (SD)-25) were compared with those of morphine after systemic administration. The analgesic potency of SD-25 was about 4 times that of morphine when administered s.c. to rats. SD-25 did not exhibit any narcotic antagonist activity. Subcutaneous administration of SD-25 produced a dose-dependent suppression of morphine withdrawal signs in morphine-dependent rats, typical morphine-like jumping in the mouse jumping test, and an increase in spontaneous locomotor activity in mice. These activities were 2-5 times those of morphine. In the anaesthetized dog, intravenous administration of SD-25 produced a 100-1000 times stronger increase in the amplitude of contractions of the jejunum than did morphine, a weaker depression in respiration than morphine, and a slight increase in blood pressure. These effects were reversed by naloxone. These results indicate that SD-25 possesses potent central nervous system actions closely similar to those of morphine, but its effect on blood pressure and respiration was weaker than that of morphine.
将Tyr-D-蛋氨酸（O）-甘氨酸-甲基苯丙氨酸（syndyphalin (SD)-25）与吗啡全身给药后的药理作用进行了比较。SD-25皮下注射给大鼠时的镇痛效力约为吗啡的4倍。SD-25未表现出任何麻醉拮抗活性。皮下注射SD-25可剂量依赖性地抑制吗啡依赖大鼠的吗啡戒断症状、小鼠跳跃试验中典型的类似吗啡的跳跃反应，并增加小鼠的自发运动活性。这些活性是吗啡的2至5倍。在麻醉犬中，静脉注射SD-25使空肠收缩幅度的增加比吗啡强100至1000倍，呼吸抑制比吗啡弱，血压略有升高。这些作用可被纳洛酮逆转。这些结果表明，SD-25具有与吗啡非常相似的强效中枢神经系统作用，但其对血压和呼吸的作用比吗啡弱。
