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Accelerated Fear Extinction by Regular Light-Intensity Exercise: A Possible Role of Hippocampal BDNF-TrkB Signaling.

Accelerated Fear Extinction by Regular Light-Intensity Exercise: A Possible Role of Hippocampal BDNF-TrkB Signaling.

Authors :
OKAMOTO, MASAHIRO
SHIMODA, RYO
AMAYA, YUKI
SOYA, SHINGO
SOYA, MARIKO
KOIZUMI, HIKARU
NAKAMURA, KENGO
HIRAGA, TAICHI
TORMA, FERENC
SOYA, HIDEAKI
Source :
Medicine & Science in Sports & Exercise. Feb2024, Vol. 56 Issue 2, p221-229. 9p.
Publication Year :
2024

Abstract

Purpose: Growing concern exists worldwide about stress-related mental disorders, such as posttraumatic stress disorder (PTSD), often linked to hippocampal dysfunctions. Recognizing this connection, regular light-intensity exercise (LIE)—such as yoga, walking, or slow jogging—may offer a solution. Easily accessible even to vulnerable individuals, LIE has been found to enhance hippocampus-based cognitive functions through the stimulation of neurotrophic factors like brain-derived neurotrophic factor (BDNF). A prior study that demonstrated BDNF's role in extinguishing original fear memory further leads us to propose that a consistent LIE training might drive fear extinction learning, offering potential therapeutic benefits through BDNF signaling. Methods: Eleven-week-old Wistar rats underwent 4 wk of training under conditions of sedentary, LIE, or moderate-intensity exercise (MOE) after contextual or auditory fear conditioning. Subsequently, fear extinction tests were performed. We then administered intraperitoneal (i.p.) ANA-12, a selective antagonist of tropomyosin receptor kinase B (TrkB), or a vehicle to explore the role of BDNF signaling in exercise-induced fear extinction among the LIE rats. Following the regular exercise training, further fear extinction tests were conducted, and hippocampal protein analysis was performed using Western blotting. Results: Both LIE and MOE over 4 wk accelerated hippocampus-associated contextual fear extinction compared with sedentary. In addition, 4 wk of LIE with i.p. administered vehicle increased hippocampal BDNF and TrkB protein levels. In contrast, i.p. ANA-12 administration fully blocked the LIE-enhanced protein levels and its effect on contextual fear extinction. Conclusions: Our findings reveal that LIE regimen promotes fear extinction learning, at least partially tied to hippocampal BDNF-TrkB signaling. This suggests that even regular light exercise could alleviate the excessive fear response in anxiety disorders and PTSD, providing hope for those affected. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01959131
Volume :
56
Issue :
2
Database :
Academic Search Index
Journal :
Medicine & Science in Sports & Exercise
Publication Type :
Academic Journal
Accession number :
175410520
Full Text :
https://doi.org/10.1249/MSS.0000000000003312