Effects of previous physical exercise to chronic stress on long‐term aversive memory and oxidative stress in amygdala and hippocampus of rats

Abstract

Since stressful situations are considered risk factors for the development of depression and there are few studies evaluating prevention therapies for this disease, in the present study we evaluated the effect of previous physical exercise in animals subjected to chronic variable stress (CVS), an animal model of depression, on behavior tasks. We also investigated some parameters of oxidative stress and Na, K-ATPase activity, immunocontent and gene expression of alpha subunits in amygdala and hippocampus of rats. Young male rats were randomized into four study groups (control, exercised, stressed, exercised+stressed). The animals were subjected to controlled exercise treadmill for 20min,three times a week, for two months prior to submission to the CVS (40days). Results show that CVS impaired performance in inhibitory avoidance at 24h and 7days after training session. CVS induced oxidative stress, increasing reactive species, lipoperoxidation and protein damage, and decreasing the activity of antioxidant enzymes. The activity of Na, K-ATPase was decreased, but the immunocontents and gene expression of catalytic subunits were not altered. The previous physical exercise was able to improve performance in inhibitory avoidance at 24h after training; additionally, exercise prevented oxidative damage, but was unable to reverse completely the changes observed on the enzymatic activities. Our findings suggest that physical exercise during the developmental period may protect against aversive memory impairment and brain oxidative damage caused by chronic stress exposure later in life.

High-Salt Diet in the Pre- and Postweaning Periods Leads to Amygdala Oxidative Stress and Changes in Locomotion and Anxiety-Like Behaviors of Male Wistar Rats

“…It is important to note that the amygdala plays a key role in the interpretation of environmental threats. Sensory stimuli are received in the amygdala that imbues them with emotional value and processing the outcomes as negative or positive valence, directly influencing anxiety-like behaviors mainly through the serotonergic system ( Calhoon and Tye, 2015 ; dos Santos et al, 2017 ; de Lima et al, 2020 ). It is possible that diet-associated amygdala oxidative stress may be related to the behavioral alterations observed in the EPM and the OF tests; however, no clear patterns linking behavioral and redox readouts were noticeable in this study.…”

“…However, to the best of our knowledge, there are no studies evaluating the amygdala redox status after administration of a high-salt diet, either before weaning (preweaning) or after weaning (postweaning). Noteworthy, the amygdala is a major brain region in the interpretation of environmental threats, possibly related to anxiety-like and fear behaviors in rodents ( Calhoon and Tye, 2015 ; Wilson et al, 2015 ; dos Santos et al, 2017 ).…”

Treadmill Exercise Ameliorates Depression-Like Behavior in the Rats With Prenatal Dexamethasone Exposure: The Role of Hippocampal Mitochondria

“…Moreover, a number of studies have shown that exercise could improve mitochondrial function and increased anti-oxidant enzymes in the nervous tissue. For instance, Dos Santos et al (2017) showed physical exercise during the developmental period may protect against brain oxidative damage caused by chronic stress exposure later in life. In the present study, we showed that exercise ameliorates depression-like behavior whilst improves mitochondrial function in Dex offspring, indicating that improvement of mitochondrial function contributes to exercise ameliorating the behavior programmed by prenatal sGC exposure.…”

The Effect of Swimming on Anxiety-Like Behaviors and Corticosterone in Stressed and Unstressed Rats

“…Furthermore, a number of studies have shown that running training improved mitochondrial function and increased antioxidant enzymes in the nervous tissue. For example, in rats, Dos Santos et al [20] showed that running training during growth may protect the brain from oxidative damage caused by exposure to chronic stress that occurs later in life. Likewise, Gomes da Silva [21] showed that that mild-to-moderate physical activity increased hippocampal anti-inflammatory cytokine levels in older rats.…”