Effects of 6-OHDA lesion of hippocampal CA3 dopaminergic system on conditioned fear memory in rats / 中华行为医学与脑科学杂志

ABSTRACT

ObjectiveTo investigate the effects of hippocampal CA3 dopaminergic system in acquisition and consolidation of Pavlovian fear conditioning,and expression of GluR1 and NR2B in medial prefrontal cortex (mPFC),CA1 and basolateral amygdala (BLA) after fear conditioning training.MethodsBilateral injection 6-OHDA into hippocampal CA3 to lesion dopaminergic fibers 2 weeks before fear conditioning training.The change of GluR1 and NR2B were analyzed by western blot after training.ResultsCompared with the saline group ( (66.44 ± 16.58)％ ),there were significant decreases ( (39.24 ± 12.83)％,(31.15 ±6.51 )％ ) in the consolidation of short- and long- term fear memory (P ＜ 0.05 ) but not the acquisition ( ( 65.58 ± 5.33 ) ％,P ＞ 0.05).The expression of GluR1 protein was significantly increased in BLA (P＜0.01 ) but not the mPFC or hippocampal CA1 (P＞1.05 ),compared with the saline group.In addition,the expression of NR2B protein was significantly increased in the mPFC and decreased in BLA (P＜0.01) but not the hippocampal CA1 (P＞0.05),compared with the saline group.ConclusionDown-regulation of dopaminergic system in hippocampal CA3 may impair the consolidation but not the acquisition of fear memory,and also regulate the expression of GluR1,NR2B protein related to fear memory in other brain regions.