Mojtahedin A, Tamaddonfard E, Zanbouri A
Physiology Division, Department of Basic Sciences, Faculty of Veterinary Medicine, P.O. Box 1177, Urmia University, Urmia 57135, Urmia, Iran.
Pak J Biol Sci. 2008 Nov 15;11(22):2573-8. doi: 10.3923/pjbs.2008.2573.2578.
In this study, the effects of mepyramine (H1-receptor antagonist), famotidine (H2-receptor antagonist), physostigmine (a cholinesterase inhibitor) and atropine (muscarinic-receptor antagonist) have investigated on the formalin-induced nociception in rats. The effects of mepyramine and famotidine have also examined on nociceptive changes induced by physostigmine and atropine. Nociception was induced by intraplantar injection of formalin (50 microL, 1%) into the right hind paw and the time spent licking and biting of the injected paw, was taken as a measure of pain. Formalin induced a marked biphasic (first phase: 0-5 min and second phase: 15-45 min) pain response. The used drugs did not change the first phase of formalin-induced pain. Subcutaneous injection of physostigmine significantly (p<0.05) suppressed pain. Subcutaneous injection of atropine alone did not change the intensity of pain, but pretreatment with atropine significantly (p<0.05) prevented physostigmine-induced antinociception. Intraperitoneal injections of mepyramine and famotidine significantly (p<0.05) decreased pain response. Mepyramine did not significantly change, but famotidine significantly (p<0.05) prevented analgesic effect of physostigmine on pain. Atropine did not inhibit the antinociceptive effects of both mepyramine and famotidine on formalin-induced nociception. These results indicate that physostigmine through muscarinic cholinergic receptors suppresses the pain induced by formalin. Both H1 and H2 receptor antagonists produce antinociception. Histamine H2, but no H1 antagonists may be involved in physostigmine-induced antinociception.
在本研究中，已对美吡拉敏（H1受体拮抗剂）、法莫替丁（H2受体拮抗剂）、毒扁豆碱（一种胆碱酯酶抑制剂）和阿托品（毒蕈碱受体拮抗剂）对福尔马林诱导的大鼠伤害感受的影响进行了研究。还考察了美吡拉敏和法莫替丁对毒扁豆碱和阿托品诱导的伤害性变化的影响。通过将福尔马林（50微升，1%）足底注射到右后爪诱导伤害感受，将注射爪舔咬所花费的时间作为疼痛的指标。福尔马林诱导出明显的双相性（第一阶段：0 - 5分钟，第二阶段：15 - 45分钟）疼痛反应。所用药物未改变福尔马林诱导疼痛的第一阶段。皮下注射毒扁豆碱显著（p<0.05）抑制疼痛。单独皮下注射阿托品未改变疼痛强度，但用阿托品预处理显著（p<0.05）阻止了毒扁豆碱诱导的抗伤害感受作用。腹腔注射美吡拉敏和法莫替丁显著（p<0.05）降低疼痛反应。美吡拉敏无显著变化，但法莫替丁显著（p<0.05）阻止了毒扁豆碱对疼痛的镇痛作用。阿托品未抑制美吡拉敏和法莫替丁对福尔马林诱导的伤害感受的抗伤害感受作用。这些结果表明，毒扁豆碱通过毒蕈碱胆碱能受体抑制福尔马林诱导的疼痛。H1和H2受体拮抗剂均产生抗伤害感受作用。组胺H2而非H1拮抗剂可能参与毒扁豆碱诱导的抗伤害感受作用。
