Diverse Ways Stress Affects the Brain and Behavior

In a groundbreaking study published in Behavioural Brain Research, a team led by Ana Paula Silva from the University of Zurich investigated the effects of acute and chronic stress on the brain in rats. The open-access original research, titled "Distinct behavioural and neurovascular signatures induced by acute and chronic stress in rats", sheds light on the unique behavioural and biochemical profiles induced by these two types of stress.

The study revealed that acute stress induces anxiety only in male rats, as demonstrated by various tests. However, chronic stress (unpredictable chronic mild stress-uCMS) had no effect on anxiety in both sexes. Interestingly, chronic stress (uCMS) increased immobility time only in male rats, indicating depressive-like behaviour. This suggests that the response to chronic stress may differ between the sexes.

In response to chronic stress, there was an upregulation in claudin-5 protein levels only in female rats. This suggests a possible compensatory mechanism of the blood-brain barrier (BBB) in female rats, as claudin-5 is a key protein in maintaining the BBB's integrity.

Acute stress decreased immobility time in the forced swimming test in both male and female rats, indicating a coping strategy. However, acute stress significantly reduced occludin and VEGF protein levels in both sexes, highlighting significant alterations in the neurovasculature. Despite these changes, both types of stress had no major impact on TNF-α, GFAP, and C3/C3aR proteins.

The findings of this study suggest that acute and chronic stress induce distinct behavioural and biochemical profiles, particularly affecting BBB proteins. This research not only deepens our understanding of the complex effects of stress on the brain but also opens up new avenues for research into potential sex-specific interventions for stress-related disorders.