Sardari Maryam, Rezayof Ameneh, Khodagholi Fariba, Zarrindast Mohammad-Reza
Department of Animal Biology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
Neuroscience Research Center, Shahid Beheshti University of Medical Science, Tehran, Iran.
Int J Neuropsychopharmacol. 2014 Apr;17(4):603-12. doi: 10.1017/S1461145713001363. Epub 2013 Nov 26.
The present study was designed to investigate the involvement of GABA-A receptors of the basolateral amygdala (BLA) in the impairing effect of acute stress on memory retrieval. The BLAs of adult male Wistar rats were bilaterally cannulated and memory retrieval was measured in a step-through type passive avoidance apparatus. Acute stress was evoked by placing the animals on an elevated platform for 10, 20 and 30 min. The results indicated that exposure to 20 and 30 min stress, but not 10 min, before memory retrieval testing (pre-test exposure to stress) decreased the step-through latency, indicating stress-induced memory retrieval impairment. Intra-BLA microinjection of a GABA-A receptor agonist, muscimol (0.005-0.02 μg/rat), 5 min before exposure to an ineffective stress (10 min exposure to stress) induced memory retrieval impairment. It is important to note that pre-test intra-BLA microinjection of the same doses of muscimol had no effect on memory retrieval in the rats unexposed to 10 min stress. The blockade of GABA-A receptors of the BLA by injecting an antagonist, bicuculline (0.4-0.5 μg/rat), 5 min before 20 min exposure to stress, prevented stress-induced memory retrieval. Pre-test intra-BLA microinjection of the same doses of bicuculline (0.4-0.5 μg/rat) in rats unexposed to 20 min stress had no effect on memory retrieval. In addition, pre-treatment with bicuculline (0.1-0.4 μg/rat, intra-BLA) reversed muscimol (0.02 μg/rat, intra-BLA)-induced potentiation on the effect of stress in passive avoidance learning. It can be concluded that pre-test exposure to stress can induce memory retrieval impairment and the BLA GABA-A receptors may be involved in stress-induced memory retrieval impairment.
本研究旨在探讨基底外侧杏仁核（BLA）的γ-氨基丁酸A（GABA-A）受体在急性应激对记忆提取的损害作用中的参与情况。对成年雄性Wistar大鼠的双侧杏仁核进行插管，并在穿梭箱式被动回避装置中测量记忆提取情况。通过将动物置于高架平台上10、20和30分钟来诱发急性应激。结果表明，在记忆提取测试前（测试前暴露于应激）暴露于20和30分钟应激，但不是10分钟，会缩短穿梭潜伏期，表明应激诱导的记忆提取受损。在暴露于无效应激（10分钟应激暴露）前5分钟，向BLA内微量注射GABA-A受体激动剂蝇蕈醇（0.005-0.02μg/大鼠）会诱导记忆提取受损。需要注意的是，在未暴露于10分钟应激的大鼠中，测试前向BLA内微量注射相同剂量的蝇蕈醇对记忆提取没有影响。在暴露于20分钟应激前5分钟，通过注射拮抗剂荷包牡丹碱（0.4-0.5μg/大鼠）阻断BLA的GABA-A受体，可防止应激诱导的记忆提取受损。在未暴露于20分钟应激的大鼠中，测试前向BLA内微量注射相同剂量的荷包牡丹碱（0.4-0.5μg/大鼠）对记忆提取没有影响。此外，用荷包牡丹碱（0.1-0.4μg/大鼠，BLA内注射）预处理可逆转蝇蕈醇（0.02μg/大鼠，BLA内注射）诱导的被动回避学习中应激效应的增强。可以得出结论，测试前暴露于应激可诱导记忆提取受损，并且BLA的GABA-A受体可能参与应激诱导的记忆提取受损。
