Maia Juliana L, Lima-Júnior Roberto C P, Melo Caroline M, David Juceni P, David Jorge M, Campos Adriana R, Santos Flávia A, Rao Vietla S N
Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
Pharmacol Res. 2006 Oct;54(4):282-6. doi: 10.1016/j.phrs.2006.06.003. Epub 2006 Jun 30.
The anti-inflammatory pentacyclic triterpene, oleanolic acid (OA) was examined on acute nociception induced by intraplantar injection of capsaicin in mice. OA administered orally to mice at 10, 30 and 100 mgkg(-1), significantly attenuated the paw-licking response to capsaicin (1.6 microg/paw) by 53%, 68.5% and 36.6%, respectively. Ruthenium red (3 mgkg(-1), s.c.), a non-competitive vanilloid receptor (V1, TRPV1)-antagonist also suppressed the capsaicin nociception by 38.6%. The maximal antinociception produced by 30 mgkg(-1) OA was significantly blocked in animals pre-treated with naloxone (2 mgkg(-1), i.p.), the opioid antagonist; l-arginine (600 mgkg(-1), i.p.), the substrate for nitric oxide synthase; or glibenclamide (2 mgkg(-1), i.p.), the K(ATP)-channel blocker, but was unaffected by yohimbine (2 mgkg(-1), i.p.), an alpha(2)-adrenoceptor antagonist. In open-field and rota-rod tests that detect motor deficits, mice received 30 mgkg(-1) OA did not manifest any effect per se, indicating that the observed antinociception is not a consequence of motor abnormality. These data suggest that OA inhibits capsaicin-evoked acute nociception due to mechanisms possibly involving endogenous opioids, nitric oxide, and K(ATP)-channel opening.
抗炎五环三萜齐墩果酸（OA）在小鼠足底注射辣椒素诱导的急性伤害感受实验中接受了检测。以10、30和100 mgkg(-1)的剂量给小鼠口服OA，分别使对辣椒素（1.6微克/爪）的舔爪反应显著减弱了53%、68.5%和36.6%。钌红（3 mgkg(-1)，皮下注射），一种非竞争性香草酸受体（V1，TRPV1）拮抗剂，也使辣椒素伤害感受抑制了38.6%。用阿片类拮抗剂纳洛酮（2 mgkg(-1)，腹腔注射）、一氧化氮合酶的底物L-精氨酸（600 mgkg(-1)，腹腔注射）或K(ATP)通道阻滞剂格列本脲（2 mgkg(-1)，腹腔注射）预处理动物后，30 mgkg(-1) OA产生的最大镇痛作用被显著阻断，但不受α(2)肾上腺素能受体拮抗剂育亨宾（2 mgkg(-1)，腹腔注射）的影响。在检测运动功能缺陷的旷场试验和转棒试验中，接受30 mgkg(-1) OA的小鼠本身未表现出任何影响，这表明观察到的镇痛作用不是运动异常的结果。这些数据表明，OA抑制辣椒素诱发的急性伤害感受，其机制可能涉及内源性阿片类物质、一氧化氮和K(ATP)通道开放。
