Meeting Abstract
The vertebrate stress response is considered to be a highly conserved suite of responses that are evolved to help animals survive noxious environmental stimuli. The two major pathways of the stress response include the catecholamine release that is part of the autonomic nervous system and comprises the immediate fight-or-flight response, and the slower release of corticosteroids from the hypothalamic-pituitary-adrenal axis that help orchestrate longer-term responses. These two pathways are present in every vertebrate yet examined, and the anatomical and physiological architecture underlying these pathways are consistent. Despite these structural similarities, however, recent data indicate substantial temporal and species variation in the actual regulation of these pathways. For example, activation of both pathways varies seasonally in some species but not others, and responses of both pathways can be extensively modulated by an individual’s previous experience. Given this variation, it is perhaps not surprising that it is proving difficult to correlate individual stress responses with differences in fitness outcomes. The likely solution is to focus on multifactorial downstream measurements of catecholamine and corticosteroid function, rather than solely on hormone titers. Moving beyond hormone titers could help clarify how the stress response can increase fitness.
