Suzuki T, Kishimoto Y, Misawa M
Department of Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
Life Sci. 1996;59(19):1667-74. doi: 10.1016/0024-3205(96)00498-5.
Morphine-, methamphetamine- and cocaine-induced place preferences under inflammation produced by unilateral injections of 2.5% formalin (50 microliters) and 1% carrageenan (100 microliters) into the hind paw were examined in rats. Formalin and carrageenan reduced the paw pressure threshold, and this hyperalgesia lasted for 9 and 13 days, respectively. Morphine-, cocaine- and methamphetamine-induced place preferences were significantly attenuated in inflamed groups as compared with the respective noninflamed groups. However, indomethacin failed to produce a place preference in either group. Furthermore, the morphine-induced place preference in the inflamed group gradually recovered to the respective control level as the inflammation healed. These results suggest that the rewarding effects of morphine, cocaine and methamphetamine are attenuated in the presence of inflammatory nociception.
在大鼠中，研究了单侧后爪注射2.5%福尔马林（50微升）和1%角叉菜胶（100微升）所产生的炎症状态下，吗啡、甲基苯丙胺和可卡因诱导的位置偏爱。福尔马林和角叉菜胶降低了爪部压力阈值，且这种痛觉过敏分别持续9天和13天。与各自的非炎症组相比，炎症组中吗啡、可卡因和甲基苯丙胺诱导的位置偏爱显著减弱。然而，吲哚美辛在两组中均未产生位置偏爱。此外，随着炎症愈合，炎症组中吗啡诱导的位置偏爱逐渐恢复到各自的对照水平。这些结果表明，在存在炎性伤害性感受的情况下，吗啡、可卡因和甲基苯丙胺的奖赏效应减弱。
