Semnan University of Medical Sciences

Research and Technology Vice Chancellor

Dadkhah, Masoumeh and Abdullahi, Payman Raise and Rashidy-Pour, Ali and Sameni, Hamid Reza and Vafaei, Abbas Ali (2018) Infralimbic dopamine D2 receptors mediate glucocorticoid-induced facilitation of auditory fear memory extinction in rats. Brain Research, 1682. pp. 84-92. ISSN 00068993

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The infralimbic (IL) cortex of the medial prefrontal cortex plays an important role in the extinction of fear memory. Also, it has been showed that both brain glucocorticoid and dopamine receptors are involved in many processes such as fear extinction that drive learning and memory; however, the interaction of these receptors in the IL cortex remains unclear. We examined a putative interaction between the effects of glucocorticoid and dopamine receptors stimulation in the IL cortex on fear memory extinction in an auditory fear conditioning paradigm in male rats. Corticosterone (the endogenous glucocorticoid receptor ligand), or RU38486 (the synthetic glucocorticoid receptor antagonist) microinfusion into the IL cortex 10 min before test 1 attenuated auditory fear expression at tests 1-3, suggesting as an enhancement of fear extinction. The effect of corticosterone, but not RU38486 was counteracted by the dopamine D2 receptor antagonist sulpiride pre-treatment administered into the IL (at a dose that failed to alter freezing behavior on its own). In contrast, intra-IL infusion of the dopamine D1 receptor antagonist SCH23390 pre-treatment failed to alter freezing behavior. These findings provide evidence for the involvement of the IL cortex D2 receptors in CORT-induced facilitation of fear memory extinction. KEYWORDS: Auditory fear conditioning; Dopamine receptors; Glucocorticoid; Infralimbic cortex

Item Type: Article
Subjects: R Medicine > R Medicine (General)
Divisions: Faculty of Medical Sciences > School of Medicine
Depositing User: Mr Vahab Moshtaghi
Date Deposited: 30 Apr 2018 14:03
Last Modified: 23 May 2018 09:56

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