IMR Press / JIN / Volume 21 / Issue 6 / DOI: 10.31083/j.jin2106173
Open Access Original Research
High Salt Intake Induces Active Coping Behaviors by Enhancing the Resilience against Psychological Stress in Mice
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1 Department of Pharmacology, School of Pharmaceutical Science, Ohu University, 963-8611 Fukushima, Japan
2 Department of Cellular Pathology, Institute for Developmental Research, Aichi Developmental Disability Center, 480-0392 Aichi, Japan
*Correspondence: (Kenjiro Seki)
Academic Editor: Drozdstoy Stoyanov
J. Integr. Neurosci. 2022, 21(6), 173;
Submitted: 26 June 2022 | Revised: 11 August 2022 | Accepted: 12 August 2022 | Published: 1 November 2022
(This article belongs to the Special Issue Advances in Depression Research)
Copyright: © 2022 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.

Background: High salt intake increases the active coping behavior during psychological stress. Acute fear-related severe stress enhances passive coping behavior during subsequent inescapable stress. Methods: We investigated the effect of high salt intake (2%) for 5 consecutive days on the coping behavior in C57BL6 mice which employing the tail suspension test (TST) at 1 h after the exposure to inescapable innate fear using 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a synthetic component of fox feces. By using a different mouse group, to investigated whether anxiety-like behavior was correlated with coping behavior during the TST, we performed the elevated-plus maze (EPM) test at 1 h before the TST without TMT. Results: Both the distance traveled and the number of entries in the central zone of test box during TMT were negatively correlated with freezing time in both sodium- and water-intake mice. Sodium-intake increased the preference for central zone during TMT exposure, but did not change fear sensitivity and locomotor activity. Sodium-intake also prevented that TMT-induced increase in the immobility time during TST. The immobility time during TST was positively correlated with freezing time during TMT exposure in sodium-intake, but not in water-intake mice. Furthermore, the immobility time during TST in sodium-intake mice correlated with the distance traveled and with the number of entries in the central zone during TMT. Sodium intake also increased the number of entries and the time spent in the open arm of the EPM, indicating that high salt intake had an anxiolytic effect. However, neither the number of entries nor the time spent in the open arm of the EPM were correlated with immobility time during TST in sodium-intake mice. Conclusions: We conclude that a high salt intake induces active coping behavior after experiencing fear stress by enhancing stress resilience rather than by reducing the anxiety level.

active coping behavior
high salt intake
inescapable innate fear stress
stress resilience
1923/Salt Science Research Foundation
JP19K06959/Grantin-Aid for Scientific Research (C) from the Japan Society for the Promotion of Science (JSPS)
Fig. 1.
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