Neurobiology and Developmental Biology Laboratory, Faculty of Biosciences, Pontifical Catholic University, Porto Alegre, RS, Brazil.
Neurobiol Learn Mem. 2011 Mar;95(3):305-10. doi: 10.1016/j.nlm.2010.12.007. Epub 2010 Dec 25.
The role of dopamine receptors in regulating the formation of recognition memory remains poorly understood. Here we show the effects of systemic administration of dopamine receptor agonists and antagonists on the formation of memory for novel object recognition in rats. In Experiment I, rats received an intraperitoneal (i.p.) injection of vehicle, the selective D1 receptor agonist SKF38393 (1.0 and 5.0mg/kg), or the D2 receptor agonist quinpirole (1.0 and 5.0mg/kg) immediately after training. In Experiment II, rats received an injection of vehicle, the dopamine receptor antagonist SCH23390 (0.1 and 0.05 mg/kg), or the D2 receptor antagonist raclopride (0.5 and 0.1mg/kg) before training, followed by an injection of vehicle or the nonselective dopamine receptor agonist apomorphine (0.05 mg/kg) immediately after training. SKF38393 at 5mg/kg produced an enhancement of novel object recognition memory measured at both 24 and 72 h after training, whereas the dose of 10mg/kg impaired 24-h retention. Posttraining administration of quinpirole did not affect 24-h retention. Apomorphine enhanced memory in rats given pretraining raclopride, suggesting that the effect was mediated by selective activation of D1 receptors. The results indicate that activation of D1 receptors can enhance recognition memory consolidation. Importantly, pharmacological activation of D1 receptors enhanced novel object recognition memory even under conditions in which control rats showed significant retention.
多巴胺受体在调节识别记忆的形成中的作用仍知之甚少。在这里，我们展示了系统给予多巴胺受体激动剂和拮抗剂对大鼠新物体识别记忆形成的影响。在实验 I 中，大鼠在训练后立即接受腹腔内（i.p.）注射载体、选择性 D1 受体激动剂 SKF38393（1.0 和 5.0mg/kg）或 D2 受体激动剂喹吡罗（1.0 和 5.0mg/kg）。在实验 II 中，大鼠在训练前接受载体、多巴胺受体拮抗剂 SCH23390（0.1 和 0.05mg/kg）或 D2 受体拮抗剂氯丙嗪（0.5 和 0.1mg/kg）的注射，然后在训练后立即接受载体或非选择性多巴胺受体激动剂阿扑吗啡（0.05mg/kg）的注射。SKF38393 5mg/kg 在训练后 24 和 72 小时均可增强新物体识别记忆，而 10mg/kg 的剂量则损害 24 小时的保留。训练后给予喹吡罗不会影响 24 小时的保留。阿扑吗啡增强了在预先给予氯丙嗪的大鼠中的记忆，表明该效应是通过选择性激活 D1 受体介导的。结果表明，D1 受体的激活可以增强识别记忆的巩固。重要的是，即使在控制大鼠表现出明显保留的情况下，药理学激活 D1 受体也能增强新物体识别记忆。
