BACKGROUND There is evidence that post-training exposure to nicotine, cocaine, and their conditioned stimuli (CS), enhance memory consolidation in rats. The present study assessed the effects of blocking noradrenergic and dopaminergic receptors on nicotine and cocaine unconditioned and conditioned memory modulation. METHODS Males Sprague-Dawley rats tested on the spontaneous object recognition task received post-sample exposure to 0.4 mg/kg nicotine, 20 mg/kg cocaine, or their CSs, in combination with 5-10 mg/kg propranolol (PRO; beta-adrenergic antagonist) or 0.2-0.6 mg/kg pimozide (PIM; dopamine D2 receptor antagonist). The CSs were established by confining rats in a chamber (the CS +) after injections of 0.4 mg/kg nicotine, or 20 mg/kg cocaine, for 2 h and in another chamber (the CS -) after injections of vehicle, repeated over 10 days (5 drug/CS + and 5 vehicle/CS - pairings in total). Object memory was tested 72 h post sample in drug-free animals. RESULTS Co-administration of PRO or PIM blocked the memory-enhancing effects of post-training injections of nicotine, cocaine, and, importantly, exposure to their CSs. CONCLUSIONS These data suggest that nicotine, cocaine as well as their conditioned stimuli share actions on overlapping noradrenergic and dopaminergic systems to modulate memory consolidation.

中文翻译：

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尼古丁、可卡因及其条件刺激的记忆增强作用；β-肾上腺素能和多巴胺 D2 受体拮抗剂的作用。

背景有证据表明，训练后接触尼古丁、可卡因及其条件性刺激物 (CS) 可增强大鼠的记忆巩固。本研究评估了阻断去甲肾上腺素能和多巴胺能受体对尼古丁和可卡因无条件和有条件的记忆调节的影响。方法 在自发物体识别任务中测试的雄性 Sprague-Dawley 大鼠接受样品后暴露于 0.4 mg/kg 尼古丁、20 mg/kg 可卡因或它们的 CS，以及 5-10 mg/kg 心得安（PRO；β-肾上腺素能拮抗剂）或 0.2-0.6 mg/kg 匹莫齐特（PIM；多巴胺 D2 受体拮抗剂）。CSs 是通过在注射 0.4 mg/kg 尼古丁或 20 mg/kg 可卡因后将大鼠关在一个室 (CS +) 中 2 小时并在注射载体后在另一个室 (CS -) 中建立的，重复超过 10 天（总共 5 种药物/CS + 和 5 种载体/CS - 配对）。在无药物动物样本后 72 小时测试对象记忆。结果 PRO 或 PIM 的共同给药阻止了训练后注射尼古丁、可卡因以及重要的是暴露于他们的 CSs 的记忆增强作用。结论 这些数据表明，尼古丁、可卡因以及它们的条件刺激对重叠的去甲肾上腺素能和多巴胺能系统有共同作用，以调节记忆巩固。