Neuroscience Program Muhlenberg College, Allentown, PA 18104, USA.
Neurobiol Learn Mem. 2011 May;95(4):484-90. doi: 10.1016/j.nlm.2011.02.011. Epub 2011 Mar 1.
The present study investigated whether memory for extinction in an appetitive task (the sand maze) could be attenuated by administration of cycloheximide (protein synthesis inhibitor) or propranolol (β-adrenergic receptor antagonist). Ninety-day-old male Long-Evans rats were trained to retrieve a sweet cereal reinforcer from an open container in the sand maze. One day following this non-spatial training, rats received three extinction trials in which they were placed in the maze with the reinforcer present, but unattainable. Thirty minutes prior to the first extinction trial, rats received an intraperitoneal injection of cycloheximide (1mg/kg), propranolol (25mg/kg), or vehicle (1mg/kg distilled water). Twenty-four hours later, rats were tested in the sand maze with the reinforcer again available. Results from the test trial showed that both cycloheximide and propranolol groups found the reinforcer more quickly than controls. Two weeks later, rats were trained on a spatial version of the sand maze in which they had to search for a buried reinforcer using extramaze cues. Cycloheximide and propranolol groups learned this task significantly faster than the control group, demonstrating the long-lasting effect of cycloheximide and propranolol on the blocking of memory for extinction.
本研究旨在探讨在一项奖赏性任务（沙迷宫）中，是否可以通过给予环己亚胺（蛋白质合成抑制剂）或普萘洛尔（β-肾上腺素能受体拮抗剂）来削弱记忆消退。90 日龄雄性 Long-Evans 大鼠接受训练，从沙迷宫中的开口容器中获取甜麦片强化物。在完成非空间训练的一天后，大鼠接受了三次消退试验，在试验中，大鼠被置于迷宫中，强化物存在但无法获得。在第一次消退试验前 30 分钟，大鼠接受了腹腔注射环己亚胺（1mg/kg）、普萘洛尔（25mg/kg）或载体（1mg/kg 蒸馏水）。24 小时后，大鼠再次在沙迷宫中接受测试，强化物再次可用。测试试验的结果表明，环己亚胺组和普萘洛尔组都比对照组更快地找到了强化物。两周后，大鼠接受了沙迷宫的空间版本训练，他们必须使用额外的线索来寻找埋藏的强化物。环己亚胺组和普萘洛尔组学习这个任务的速度明显快于对照组，这表明环己亚胺和普萘洛尔对记忆消退的阻断具有持久的效果。
