Department of Basic Medicine, Medical School, Kunming University of Science and Technology, Kunming, Yunnan, China.
Laboratory of Ecology & Evolutionary Biology, Yunnan University, Kunming, Yunnan, China.
Clin Exp Pharmacol Physiol. 2018 Apr;45(4):335-343. doi: 10.1111/1440-1681.12889. Epub 2017 Dec 19.
Both opiates and dopamine play important roles in learning and memory. Although synergistic action between these two neurotransmitters has been found, their functional roles remain unclear. Here, low dose morphine (2.5 mg/kg) and low dose dopamine receptor agonists (apomorphine 0.05 mg/kg; SKF38393 0.01 mg/kg; bromocriptine 0.05 mg/kg), which have no effects on spatial recognition memory, were injected intraperitoneally into mice 30 minutes before a memory test in a two-trial recognition Y-maze. The Y-maze is based on the innate tendency of rodents to explore novel environments and is therefore suitable for exploring the effects of morphine on learning and memory. Our results showed that both D1-like and D2-like dopamine receptor agonists dose-dependently impaired the retrieval of spatial recognition memory in the Y-maze, and co-administration of memory ineffective doses of apomorphine (0.05 mg/kg), SKF38393 (0.01 mg/kg), or bromocriptine (0.05 mg/kg) and of morphine (2.5 mg/kg) resulted in impaired spatial recognition memory retrieval in mice. These findings suggest the existence of interactions between morphine and dopamine receptor agonists in memory processing and that activation of the dopamine system might contribute to morphine-induced impairment of memory, which could provide insight into human addiction.
阿片类药物和多巴胺在学习和记忆中都起着重要作用。虽然已经发现这两种神经递质之间存在协同作用，但它们的功能作用仍不清楚。在这里，低剂量吗啡（2.5mg/kg）和低剂量多巴胺受体激动剂（阿扑吗啡 0.05mg/kg；SKF38393 0.01mg/kg；溴隐亭 0.05mg/kg），它们对空间识别记忆没有影响，在记忆测试前 30 分钟被腹膜内注射到小鼠体内，然后在双试验识别 Y 迷宫中进行记忆测试。Y 迷宫基于啮齿动物探索新环境的先天倾向，因此适合于探索吗啡对学习和记忆的影响。我们的结果表明，D1 样和 D2 样多巴胺受体激动剂都剂量依赖性地损害了 Y 迷宫中空间识别记忆的检索，而给予记忆无效剂量的阿扑吗啡（0.05mg/kg）、SKF38393（0.01mg/kg）或溴隐亭（0.05mg/kg）和吗啡（2.5mg/kg）的共同给药导致小鼠的空间识别记忆检索受损。这些发现表明，吗啡和多巴胺受体激动剂之间在记忆处理中存在相互作用，多巴胺系统的激活可能有助于吗啡引起的记忆损伤，这可能为人类成瘾提供了深入的了解。
