Xu Q, Jin R L, Wu Y Y
Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing.
Zhongguo Yao Li Xue Bao. 1993 Nov;14(6):495-500.
The analgesic effect of protopine (Pro), an alkaloid isolated from Papaveraceae, was confirmed by tail-pinch and hot-plate tests when given sc 10-40 mg.kg-1, and 20-40 mg.kg-1 inhibited the spontaneous movements of mice. Pro 40 mg.kg-1 increased the sleeping rate, prolonged the sleeping duration, and shortened the sleeping latency in mice hypnotized by ip pentobarbital sodium 30 mg.kg-1. Pro 10-40 mg.kg-1 did not affect the inflammatory reaction induced by xylene and egg white. An icv injection of Pro 20-200 micrograms/mouse showed a remarkable analgesic effect in mice. The icv pretreatment of naloxone 2 micrograms blocked the analgesic effect completely. CaCl2 40 micrograms/mouse (ICV) or methotrexate 10 mg.kg-1 (ip), an agonist of Ca2+ channel, showed a complete blockade of the analgesia, while nifedipine 100 mg.kg-1(po), a blocker of Ca2+ channel, enhanced the analgesic effect. The ip pretreatment of reserpine 4 mg.kg-1 reduced the Pro analgesia. Phentolamine 10 mg.kg-1(ip), an alpha-adrenergic blocker, tended to weaken the analgesia, but propranolol 10 mg.kg-1(ip), a beta-blocker, did not affect it. These results suggest that Pro displays its analgesic effect mainly through the opioid and calcium systems and partly through the adrenergic mechanism.
从罂粟科植物中分离得到的生物碱原阿片碱（Pro），皮下注射10 - 40mg·kg-1时，通过尾夹法和热板法试验证实其具有镇痛作用，20 - 40mg·kg-1可抑制小鼠的自发活动。40mg·kg-1的Pro可提高腹腔注射30mg·kg-1戊巴比妥钠诱导的小鼠睡眠率，延长睡眠时间，并缩短睡眠潜伏期。10 - 40mg·kg-1的Pro对二甲苯和蛋清诱导的炎症反应无影响。脑室内注射20 - 200μg/小鼠的Pro对小鼠有显著镇痛作用。脑室内预先注射2μg纳洛酮可完全阻断镇痛作用。40μg/小鼠（脑室内注射）的氯化钙或10mg·kg-1（腹腔注射）的甲氨蝶呤（一种Ca2+通道激动剂）可完全阻断镇痛作用，而100mg·kg-1（口服）的硝苯地平（一种Ca2+通道阻滞剂）可增强镇痛作用。腹腔预先注射4mg·kg-1的利血平可降低Pro的镇痛作用。10mg·kg-1（腹腔注射）的酚妥拉明（一种α-肾上腺素能阻滞剂）倾向于减弱镇痛作用，但10mg·kg-1（腹腔注射）的普萘洛尔（一种β-阻滞剂）对其无影响。这些结果表明，Pro主要通过阿片类和钙系统发挥镇痛作用，部分通过肾上腺素能机制发挥作用。
