Mouse strain differences in plasma corticosterone following uncontrollable footshock

Area of Science:

• Neuroscience
• Endocrinology
• Animal Behavior

Background:

• Stress exposure triggers physiological responses, including elevated corticosterone.
• Individual differences in stress reactivity are well-documented across species.
• Mouse strain variation is a critical factor in stress response research.

Purpose of the Study:

• To investigate strain-specific differences in plasma corticosterone levels following acute footshock stress in mice.
• To examine whether these strain differences persist under chronic stress conditions.
• To correlate stress-induced hormonal changes with neurochemical and behavioral variations.

Main Methods:

• Six mouse strains (A/J, Balb/cByJ, C57BL/6J, C3H/HeJ, DBA/2J, CD-1) were exposed to acute inescapable footshock.
• Plasma corticosterone concentrations were measured at various time points post-stress.
• Chronic stressor regimens were also employed to assess long-term effects.
• Data were compared with existing findings on brain neurotransmitter levels and behavioral performance.

Main Results:

• Acute footshock significantly increased plasma corticosterone in all six mouse strains.
• The magnitude of corticosterone elevation and recovery time varied considerably among strains.
• Strain-specific stress responses observed after acute shock were also evident following chronic stress.
• These hormonal variations were linked to previously reported strain differences in brain norepinephrine, dopamine, serotonin, and behavior.

Conclusions:

• Mouse strain is a significant determinant of acute and chronic stress-induced corticosterone responses.
• Variations in stress hormone levels across strains may underlie observed differences in neurochemistry and behavior.
• Understanding these strain-specific stress phenotypes is crucial for modeling stress-related disorders.