Lalonde R, Joyal C C
Hôtel-Dieu Hospital, Neurology Service, Montreal, Quebec, Canada.
Pharmacol Biochem Behav. 1991 Aug;39(4):829-33. doi: 10.1016/0091-3057(91)90039-5.
The effects of ketamine, an NMDA receptor antagonist, and 1-glutamic acid diethyl ester (LGDE), a non-NMDA glutamate antagonist, were evaluated in the acquisition of concept learning in a water maze. In concept learning, the rats must locate an invisible platform whose location changes from day to day. In spatial learning (Morris task), the rats must locate an invisible (or visible) platform whose location does not change. Ketamine increased quadrant entries at 5, 10 and 20 mg/kg, and latencies at 10 and 20 mg/kg on the final two days of training on the concept task. At 5 mg/kg ketamine disrupted concept learning but not spatial learning or visuo-motor coordination as assessed by invisible and visible platform conditions of the Morris maze. Progressively higher doses of ketamine affected first the invisible condition and then the visible platform condition. On the other hand, LGDE did not affect the Morris task at any dose. However, there was no decrease in latencies over days in concept learning at the two highest doses (240 and 360 mg/kg) of LGDE. Thus LGDE appeared to slow down decision time in the concept task but not the spatial task in the absence of an effect on quadrant entries in any version. These results indicate that NMDA receptors are involved in spatial and concept learning. Non-NMDA receptors appear to be involved only in concept learning.
在水迷宫中进行概念学习的过程中，对N-甲基-D-天冬氨酸（NMDA）受体拮抗剂氯胺酮和非NMDA谷氨酸拮抗剂谷氨酸二乙酯（LGDE）的作用进行了评估。在概念学习中，大鼠必须找到一个每天位置都发生变化的隐形平台。在空间学习（莫里斯任务）中，大鼠必须找到一个位置不变的隐形（或可见）平台。在概念任务训练的最后两天，氯胺酮在5、10和20毫克/千克剂量时增加了象限进入次数，在10和20毫克/千克剂量时延长了潜伏期。在5毫克/千克剂量时，氯胺酮破坏了概念学习，但未影响空间学习或视觉运动协调，这是通过莫里斯迷宫的隐形和可见平台条件评估得出的。氯胺酮剂量逐渐增加时，首先影响隐形条件，然后影响可见平台条件。另一方面，LGDE在任何剂量下均未影响莫里斯任务。然而，在LGDE的两个最高剂量（240和360毫克/千克）下，概念学习的潜伏期在数天内并未缩短。因此，在对任何版本的象限进入次数均无影响的情况下，LGDE似乎减缓了概念任务中的决策时间，但未影响空间任务。这些结果表明，NMDA受体参与空间和概念学习。非NMDA受体似乎仅参与概念学习。
