Kim J J, Fanselow M S, DeCola J P, Landeira-Fernandez J
Department of Psychology, University of California, Los Angeles 90024.
Behav Neurosci. 1992 Aug;106(4):591-6. doi: 10.1037//0735-7044.106.4.591.
Previous research has indicated that the competitive N-methyl-D-aspartate (NMDA) antagonist APV (DL-2-amino-5-phosphonovalerate) prevents the Pavlovian conditioning of fear to contextual stimuli when tested 24 hr, but not immediately, after training. The present study investigated this differential time-dependent effect of APV on fear conditioning. Rats were given either APV or saline and presented with 3 footshocks in a distinctive chamber. Promptly after the shock, rats that had received APV exhibited a species-typical fear response-freezing. However, the freezing lasted for only a short period of time (less than 3 min) compared with that of controls. An immediate-shock procedure showed that freezing was entirely a conditional response to the chamber. In addition, the results of a savings test suggest that APV impairs storage rather than retrieval processes. These results indicate that there are two temporally distinct associative fear processes, a short-term NMDA-independent conditional fear and a long-term NMDA-dependent conditional fear.
先前的研究表明，竞争性N-甲基-D-天冬氨酸（NMDA）拮抗剂APV（DL-2-氨基-5-磷酸戊酸）在训练后24小时（而非立即）进行测试时，可阻止恐惧对情境刺激的巴甫洛夫条件反射。本研究调查了APV对恐惧条件反射的这种不同的时间依赖性效应。给大鼠注射APV或生理盐水，并在一个独特的实验箱中给予3次足部电击。电击后立即发现，接受APV的大鼠表现出一种典型的恐惧反应——僵住。然而，与对照组相比，僵住仅持续了很短的时间（不到3分钟）。即时电击程序表明，僵住完全是对实验箱的一种条件反应。此外，节省测试的结果表明，APV损害的是记忆存储过程而非提取过程。这些结果表明，存在两个在时间上不同的关联性恐惧过程，一个是短期的不依赖NMDA的条件性恐惧，另一个是长期的依赖NMDA的条件性恐惧。
