Modulation of the Adrenocortical Response to Perturbations of the Environment

University Of California-Davis, Davis CA

Investigators

Abstract

Extreme weather events such as storms, are increasing in frequency, duration and intensity. Couple this with other global changes resulting from human disturbance and it is clear that mechanisms underlying organism-environment interactions in response to stressful environmental factors are key. These responses, often called the "stress response" help the animal cope through the modification of physiology and behaviour that promote survival. The focus here will be on the stress hormone responses, particularly from the adrenal gland, that are a highly adaptive suite of physiological and behavioral traits that are conserved across vertebrates including humans. A basic understanding of how seasonal modulations of the stress response works will allow us to predict how vertebrate organisms adjust their physiology and behaviour in response to an increasingly capricious environment as well as across a species' range with an emphasis on those populations that are on the limits of, or have pushed beyond, their geographic range. The PIs aim to educate K-12 students and teachers, while also reaching out to under-represented minorities (particularly Latinos in California) to enhance awareness, and conservation, of habitat for all organisms as well as birds. In these ways the work can be broadly disseminated to the public at large. In an era of dramatic environmental change, public awareness is critical and the broader impact activities will have far reaching influence. Mechanisms underlying organism-environment interactions in response to perturbations of the environment are key for survival. The focus here will be on the hormonal response, particularly corticosteroids from the adrenal gland. The PIs have a good understanding of the responses to environmental stress in biomedical contexts, often under the chronic stress paradigm. However, these approaches do not mimic nature in which organisms experience seasonal cycles in environmental conditions and the stress response is modulated accordingly. Understanding how individuals push the boundaries of their coping strategies as well as geographic range is critical both from a basic science standpoint and for conservation. The proposed work will assess how the adrenocortical stress response is regulated using both laboratory and field studies to inform us of what brain centers are responsible for controlling seasonal fluctuation in the stress response. In addition, the focus will be on how the activity of these brain regions fluctuates across the annual cycle of environmental severity, and also across a species' range with an emphasis on those populations that are on the limits of, or have pushed beyond, their geographic range. A basic understanding of how the HPA axis works in species that undergo seasonal modulations in the stress response will also allow the PIs to predict how vertebrate organisms adjust their physiology and behavior in response to an increasingly capricious environment.