Roles of amygdala glucocorticoid receptor in stress-modulated fear conditioning

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K06705
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurophysiology / General neuroscience
• Research Institution: University of Toyama
• Principal Investigator: Inoue Ran 富山大学, 大学院医学薬学研究部(医学), 助教 (70401817)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 扁桃体 / グルココルチコイド受容体 / 恐怖記憶

Outline of Final Research Achievements

The lateral nucleus of the amygdala (LA) is a key structure underlying auditory-cued fear conditioning.　Glucocorticoid receptor (GR) is crucial for signaling mediated by stress-induced high levels of glucocorticoids. Here, we demonstrate that genetic disruption of GR in the LA (LAGRKO) resulted in an auditory-cued fear memory deficit for strengthened conditioning. Furthermore, the suppressive effect of a single restraint stress (RS) prior to conditioning on auditory-cued fear memory in floxed GR (control) mice was abolished in LAGRKO mice. Optogenetic induction of long-term depression (LTD) at LA reduced fear memory in RS-exposed LAGRKO mice, and in contrast, induction of long-term potentiation (LTP) increased fear memory in RS-exposed floxed GR mice. These findings suggest that prior stress suppresses fear conditioning-induced LTP at auditory inputs to the LA in a GR-dependent manner, thereby protecting animals from encoding excessive cued fear memory under stress conditions.

Free Research Field

神経科学、脳科学