Shiraz Neuroscience Research Center and Department of Physiology, Shiraz University of Medical Sciences, Shiraz, Iran.
Eur J Pharmacol. 2012 Feb 29;677(1-3):107-10. doi: 10.1016/j.ejphar.2011.12.021. Epub 2011 Dec 23.
Ketamine, a non-selective inhibitor of NMDA (N-methyl-D-aspartate) channels is used in anesthetic or sub-anesthetic doses to induce analgesia, amnesia, to suppress fear, anxiety and depression. Although the ketamine's effect on memory acquisition is known, its effects on other aspects of memory are controversial. Morris water maze is a task which assesses spatial learning and memory. This study was aimed to assess the ketamine's differential effect on water maze memory acquisition, consolidation and retrieval. Male Sprague-Dawley rats (250-350 g) were trained in water maze single training session. 24h later a probe trial which was consisted of a single trial without platform was done. To assess the effect of ketamine on water maze memory acquisition it was administered before training; to assess its effect on memory consolidation it was administered immediately after training and to assess its effect on memory retrieval it was injected before probe trial. Ketamine both in sub-anesthetic and anesthetic doses impaired water maze memory acquisition, its anesthetic dose but not sub-anesthetic dose impaired memory consolidation and on retrieval stage, both doses deteriorated memory retrieval. It seems that NMDA receptor activity is not just necessary during water maze memory acquisition but also their post-learning reactivation is required to maintain memory consolidation and retrieval.
氯胺酮是一种非选择性 NMDA（N-甲基-D-天冬氨酸）通道抑制剂，以麻醉或亚麻醉剂量用于诱导镇痛、失忆、抑制恐惧、焦虑和抑郁。尽管氯胺酮对记忆获取的影响是已知的，但它对其他记忆方面的影响仍存在争议。水迷宫是评估空间学习和记忆的任务。本研究旨在评估氯胺酮对水迷宫记忆获取、巩固和检索的差异影响。雄性 Sprague-Dawley 大鼠（250-350g）在水迷宫中接受单次训练。24 小时后，进行单次无平台试验的探测试验。为了评估氯胺酮对水迷宫记忆获取的影响，在训练前给予氯胺酮；为了评估其对记忆巩固的影响，在训练后立即给予氯胺酮；为了评估其对记忆检索的影响，在探测试验前给予氯胺酮。氯胺酮在亚麻醉和麻醉剂量下均损害水迷宫记忆获取，其麻醉剂量而非亚麻醉剂量损害记忆巩固，在检索阶段，两种剂量均损害记忆检索。似乎 NMDA 受体活性不仅在水迷宫记忆获取期间是必需的，而且在学习后重新激活以维持记忆巩固和检索也是必需的。
