Baker J D, Azorlosa J L
Department of Psychology, Southeastern Louisiana University, Hammond 70402, USA.
Behav Neurosci. 1996 Jun;110(3):618-20. doi: 10.1037//0735-7044.110.3.618.
Five groups of rats were given Pavlovian fear conditioning. Four groups were then given extinction training. Prior to extinction these groups received an injection of either the noncompetitive NMDA antagonist MK-801 (0.025, 0.05, or 0.1 mg/kg) or saline. The 5th group received saline but no extinction. During testing, the extinction groups given saline or 0.025 mg/kg of MK-801 showed reduced fear, but the groups that had received the higher doses exhibited as much conditioned fear as the saline group, which had not received extinction. This study showed that MK-801 blocked extinction in a dose-dependent manner. The design of the study ruled out the possibility that the effect was due to state-dependency or to MK-801 interfering with the processing of the conditioned stimulus.
将五组大鼠进行巴甫洛夫式恐惧条件反射训练。然后，其中四组接受消退训练。在消退训练之前，这些组分别注射非竞争性NMDA拮抗剂MK-801（0.025、0.05或0.1毫克/千克）或生理盐水。第五组只接受生理盐水注射，但不进行消退训练。在测试期间，接受生理盐水或0.025毫克/千克MK-801注射的消退训练组表现出恐惧减轻，但接受较高剂量MK-801注射的组表现出与未接受消退训练的生理盐水组一样多的条件性恐惧。该研究表明，MK-801以剂量依赖性方式阻断消退。该研究的设计排除了这种效应是由于状态依赖性或MK-801干扰条件刺激处理过程的可能性。
