scholarly journals The Medial Amygdala-Medullary PrRP-Synthesizing Neuron Pathway Mediates Neuroendocrine Responses to Contextual Conditioned Fear in Male Rodents

Endocrinology ◽  
2014 ◽  
Vol 155 (8) ◽  
pp. 2996-3004 ◽  
Author(s):  
Masahide Yoshida ◽  
Yuki Takayanagi ◽  
Tatsushi Onaka
Keyword(s):  
Stress Disorder ◽  
Conditioned Fear ◽  
Fear Memory ◽  
Freezing Behavior ◽  
Medial Amygdala ◽  
Neural Pathways ◽  
Neuroendocrine Responses ◽  
Prolactin Releasing Peptide ◽  
Deficient Mice ◽  
Fear Expression

Fear responses play evolutionarily beneficial roles, although excessive fear memory can induce inappropriate fear expression observed in posttraumatic stress disorder, panic disorder, and phobia. To understand the neural machineries that underlie these disorders, it is important to clarify the neural pathways of fear responses. Contextual conditioned fear induces freezing behavior and neuroendocrine responses. Considerable evidence indicates that the central amygdala plays an essential role in expression of freezing behavior after contextual conditioned fear. On the other hand, mechanisms of neuroendocrine responses remain to be clarified. The medial amygdala (MeA), which is activated after contextual conditioned fear, was lesioned bilaterally by infusion of N-methyl-d-aspartate after training of fear conditioning. Plasma oxytocin, ACTH, and prolactin concentrations were significantly increased after contextual conditioned fear in sham-lesioned rats. In MeA-lesioned rats, these neuroendocrine responses but not freezing behavior were significantly impaired compared with those in sham-lesioned rats. In contrast, the magnitudes of neuroendocrine responses after exposure to novel environmental stimuli were not significantly different in MeA-lesioned rats and sham-lesioned rats. Contextual conditioned fear activated prolactin-releasing peptide (PrRP)-synthesizing neurons in the medulla oblongata. In MeA-lesioned rats, the percentage of PrRP-synthesizing neurons activated after contextual conditioned fear was significantly decreased. Furthermore, neuroendocrine responses after contextual conditioned fear disappeared in PrRP-deficient mice. Our findings suggest that the MeA-medullary PrRP-synthesizing neuron pathway plays an important role in neuroendocrine responses to contextual conditioned fear.

scholarly journals Role of Amygdala-Infralimbic Cortex Circuitry in Glucocorticoid-Induced Facilitation of Auditory Fear Memory Extinction

2021 ◽  
pp. 1-22
Author(s):  
Masoomeh Dadkhah ◽  
◽  
Abbas Ali Vafaei ◽  
Ali Rashidy-Pour ◽  
Parnia Trahomi ◽  
...  
Keyword(s):  
Critical Role ◽  
Fear Memory ◽  
Fear Extinction ◽  
Freezing Behavior ◽  
Extinction Training ◽  
Male Rats ◽  
Memory Extinction ◽  
The Right ◽  
Fear Expression

Purpose: The basolateral amygdala (BLA) and infralimbic area (IL) of medial prefrontal cortex (mPFC) are two inter-connected brain structures that mediate both fear memory expression and extinction. Besides the well-known role of the BLA in the acquisition and expression of fear memory, projections from IL to BLA inhibit fear expression and have a critical role in fear extinction. However, the details of IL-BLA interaction remain unclear. Here, we aimed to investigate the role of functional reciprocal interactions between BLA and IL in mediating fear memory extinction. Methods: Using lidocaine (LID), male rats underwent unilateral or bilateral inactivation of the BLA and then unilateral intra-IL infusion of CORT, prior to extinction training of auditory fear conditioning paradigm. Freezing behavior was reported as an index for the measurement of conditioned fear. Infusions were performed before the extinction training, allowing to examine the effects on fear expression and also further extinction memory. Experiments 1-3 investigated the effects of left or right infusion of CORT into IL, and LID unilaterally into BLA on fear memory extinction. Results: Results showed that intra-IL infusion of CORT in the right hemisphere reduced freezing behavior when administrated before the extinction training. Auditory fear memory extinction was impaired by asymmetric inactivation of BLA and CORT infusion in the right IL; however, the same effect was not observed with symmetric inactivation of BLA. Conclusion: It is concluded that that the IL-BLA neural circuit may provide additional evidence to contribution of this circuit in auditory fear extinction. This study demonstrate dissociable roles for right or left BLA in subserving the auditory fear extinction. Our finding also raise the possibility that left BLA-IL circuitry may contribute in mediating auditory fear memory extinction via underlying mechanisms, however further research is required.

scholarly journals Effects of swimming exercise on the extinction of fear memory in rats

2018 ◽  
Vol 120 (5) ◽  
pp. 2649-2653 ◽  
Author(s):  
Rodolfo Souza Faria ◽  
Álvaro Luiz Bianchim Bereta ◽  
Guilherme Henrique Teixeira Reis ◽  
Lourdes Bethania Braga Santos ◽  
Marcela Santos Gomes Pereira ◽  
...  
Keyword(s):  
Posttraumatic Stress Disorder ◽  
Anxiety Disorders ◽  
Posttraumatic Stress ◽  
Stress Disorder ◽  
Conditioned Fear ◽  
Fear Memory ◽  
Swimming Exercise ◽  
Extinction Process ◽  
Memory Extinction ◽  
Fear Behavior

We investigated the relation between swimming exercise and fear memory extinction. Rats that performed regular swimming exercise over 6 wk underwent fear conditioning. Twenty-eight days later, they were submitted to extinction tests. Swimming rats had enhanced extinction process throughout the 5 days of the extinction test compared with sedentary rats. This suggests that the swimming exercise accelerated the process of aversive memory extinction, reducing the expression of conditioned fear behavior. These results encourage further studies addressing the anxiolytic effects of exercise, with potential implications for anxiety disorders such as posttraumatic stress disorder. NEW & NOTEWORTHY We have shown that rats that performed regular swimming exercise over 6 wk had enhanced extinction process compared with sedentary animals. The swimming exercise may accelerate the process of aversive memory extinction, reducing the expression of conditioned fear behavior.

A Retrieval-Extinction Paradigm to Treat Conditioned Fear Memory

2014 ◽  
Vol 22 (3) ◽  
pp. 431
Author(s):  
Xiangxing ZENG ◽  
Yanhui XIANG ◽  
Juan DU ◽  
Xifu ZHENG
Keyword(s):  
Conditioned Fear ◽  
Fear Memory

scholarly journals Npas4 impairs fear memory via phosphorylated HDAC5 induced by CGRP administration in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Narumi Hashikawa-Hobara ◽  
Shuta Mishima ◽  
Chihiro Okujima ◽  
Youdai Shitanishi ◽  
Naoya Hashikawa
Keyword(s):  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Stress Disorder ◽  
Histone H3 ◽  
Fear Memory ◽  
Protein Kinase D ◽  
Post Traumatic Stress ◽  
Calcitonin Gene ◽  
Post Traumatic ◽  
H3 Acetylation

AbstractThe relationships among neuropeptide, calcitonin gene-related peptide (CGRP), and memory formation remain unclear. Here, we showed that the intracerebroventricular administration of CGRP impaired the traumatic fear memories, in a widely studied animal model of post-traumatic stress disorder. We found that CGRP administration suppressed fear memory by increasing neuronal PAS domain protein 4 (Npas4), phosphorylated histone deacetylase 5 (HDAC5), and protein kinase D (PKD). We also discovered that Npas4 knockdown inhibited CGRP-mediated fear memory. CGRP decreased the binding between HDAC5 and the Npas4 enhancer site and increased the binding between acetylated histone H3 and the Npas4 enhancer site. The pharmacological inhibition or knockdown of PKD attenuated the CGRP-mediated impairment of fear memory and the increased phosphorylation of HDAC5 and Npas4 expression. Our findings demonstrated that the CGRP-PKD pathway was associated with the histone H3 acetylation-Npas4 pathway. These results suggested a novel function for CGRP on fear memory, through epigenetic regulation.

Lack of effect of propranolol on the reconsolidation of conditioned fear memory due to a failure to engage memory destabilisation

Neuroscience ◽  
2021 ◽  
Author(s):  
Federico Rotondo ◽  
Kathryn Biddle ◽  
John Chen ◽  
Josh Ferencik ◽  
Mathilde d'Esneval ◽  
...  
Keyword(s):  
Conditioned Fear ◽  
Fear Memory

The Medial Amygdala Modulates Body Weight but not Neuroendocrine Responses to Chronic Stress

2010 ◽  
Vol 22 (1) ◽  
pp. 13-23 ◽  
Author(s):  
M. B. Solomon ◽  
K. Jones ◽  
B. A. Packard ◽  
J. P. Herman
Keyword(s):  
Body Weight ◽  
Chronic Stress ◽  
Medial Amygdala ◽  
Neuroendocrine Responses

scholarly journals Npas4 impairs fear memory via phosphorylated HDAC5 induced by CGRP administration in mice

2020 ◽  
Author(s):  
Narumi Hashikawa-Hobara ◽  
Shuta Mishima ◽  
Chihiro Okujima ◽  
Youdai Shitanishi ◽  
Naoya Hashikawa
Keyword(s):  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Stress Disorder ◽  
Histone H3 ◽  
Fear Memory ◽  
Protein Kinase D ◽  
Post Traumatic Stress ◽  
Calcitonin Gene ◽  
Post Traumatic ◽  
H3 Acetylation

Abstract The relationships among neuropeptide, calcitonin gene-related peptide (CGRP), and memory formation remain unclear. Here, we showed that the intracerebroventricular administration of CGRP impaired the traumatic fear memories, in a widely studied animal model of post-traumatic stress disorder. We found that CGRP administration suppressed fear memory by increasing neuronal PAS domain protein 4 (Npas4), phosphorylated histone deacetylase 5 (HDAC5), and protein kinase D (PKD). We also discovered that Npas4 knockdown inhibited CGRP-mediated fear memory. CGRP decreased the binding between HDAC5 and the Npas4 enhancer site and increased the binding between acetylated histone H3 and the Npas4 enhancer site. The pharmacological inhibition or knockdown of PKD attenuated the CGRP-mediated impairment of fear memory and the increased phosphorylation of HDAC5 and Npas4 expression. Our findings demonstrated that the CGRP-PKD pathway was associated with the histone H3 acetylation-Npas4 pathway. These results suggested a novel function for CGRP on fear memory, through epigenetic regulation.

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