东莨菪碱对痛和镇痛的影响

对家兔作钾离子透入法测痛,腹腔注射东莨菪碱4mg/kg,给药后30分钟痛阈提高49%。静脉注射同样剂量的东莨菪碱,给药后20分钟痛阈提高37%。侧脑室注射5 μg/只后20分钟痛阈提高53%。这些结果表明东莨菪碱有一定强度的镇痛作用。与度冷丁(60 mg/kg腹腔注射)合用痛阈提高147%,而单用度冷丁病阈升高93%,提示两药合用有协同作用。对小白鼠用热板法测痛,腹腔注射东莨菪碱1.25 mg/kg,给药后15分钟病阈提高62%。与小剂量度冷丁(10 mg/kg腹腔注射)合用,给药后15分钟痛阈提高126%,而单用小剂量度冷丁痛阈仅提高23%。这些与用家兔实验的结果一致。给家兔侧脑室注射去甲肾上腺素20 μg/只后,10分钟时痛阈下降46%,并能减弱度冷丁的镇痛作用。东莨菪碱与去甲肾上腺素合用,则能拮抗后者的抗镇痛作用。因此推测东莨菪碱的镇痛和加强度冷丁镇痛的作用,可能与其抗去甲肾上腺素的作用有关。

EFFECT OF SCOPOLAMINE ON PAIN AND ANALGESIC ACTIVITY

Thirty minutes after the intraperitoneal administration of scopolamine to rabbits at a dose of 4 mg/kg, the pain threshold, measured by the potassium iontophoresis method, was increased by 49%. If the same dose of scopolamine was given intravenously, the pain threshold was increased by 37% when measured 20 minutes after administration. However, when 5 μg of scopolamine were given to each rabbit intraventricularly, the pain threshold was increased by 53%. These results indicate that scopolamine has certain analgesic action. When scopolamine (4mg/kg) was given in combination with dolantin (60 mg/kg) intraperitoneally, the pain threshold was increased by 147%. In contrast, if dolantin (60 mg/kg) was given alone, the pain threshold was increased by 93%. It appears that there is a synergistic action between scopolamine and dolantin.When scopolamine (1.25 mg/kg) or dolantin (10 mg/kg) was given to rats intraperitoneally the pain threshold, measured by the hot plate method 15 minutes after drug administration, was increased by 62% or 23%, respectively. When these two drugs were given in combination, the pain threshold was found to beincreased by 126%. this is consistant with the result obtained in the experiments for rabbits.Ten minutes after the intraventricular administration of 20 μg of noradrenaline to a rabbit, the pain threshold was decreased by 46%. When noradrenaline was given in combination with dolantin, the analgesic effect of the latter compound was also diminished. In addition, administration of scopolamine with noradrenaline, the pain threshold decreasing effect of the latter was antagonized. These results seem to suggest that the analgesic effect of scopolamine is related to. its antagonistic action to the effects of noradrenaline.