Cortisol responses and social buffering: a study throughout the life span

Area of Science:

• Neuroscience
• Behavioral Endocrinology
• Animal Behavior

Background:

• Social buffering of stress responses is crucial for well-being.
• The role of social support in modulating the hypothalamic-pituitary-adrenal (HPA) axis is well-documented.
• However, age-specific changes in social buffering capacity remain underexplored.

Purpose of the Study:

• To investigate how adult females influence plasma cortisol responses in male guinea pigs across different life stages.
• To determine if the familiarity of the female affects her ability to buffer stress.
• To identify age-specific patterns in social buffering of the HPA axis.

Main Methods:

• Male guinea pigs were studied at four developmental stages: preweaning, periadolescent, sexually but not socially mature, and sexually and socially mature.
• Males were exposed to a novel environment for 4 hours, either alone, with an unfamiliar adult female, or with a favored adult female.
• Plasma cortisol levels were measured to assess the stress response.

Main Results:

• In preweaning males, the mother (favored female) reduced cortisol response; unfamiliar females did not.
• In periadolescents, an unfamiliar female buffered the cortisol response, but the favored female did not.
• Cortisol response was suppressed in sexually but not socially mature males, unaffected by females.
• In sexually and socially mature males, the favored female moderated cortisol levels, but unfamiliar females did not.

Conclusions:

• Female social buffering of cortisol responses exhibits significant age-dependent changes in male guinea pigs.
• A period of suppressed cortisol response to novelty was observed in maturing males.
• These findings suggest a dynamic interplay between social environment, development, and stress regulation, potentially applicable to other group-living mammals.