Examination of biological factors that mediate the influence of physical activity on palatability driven feeding

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Palatability driven feeding- consuming food for pleasure, and voluntary physical activity are mediated by and influence similar neural mechanisms. However, the interaction between the two behaviors is not well established. Considering both behaviors are facilitated by opioids within the nucleus accumbens (NAc), it is a likely target system to arbitrate such effects. Furthermore, it is yet to be determined how biological factors between subjects such as sex or genetics may influence this interaction. The experiments presented in this dissertation utilize unique models applying systems and behavioral neuroscience approaches to test the hypothesis that differences in biological factors may mediate the effect of physical activity on palatability driven feeding. All studies included both male and female subjects in order to account for potential sex differences in the behavioral and physiological response to physical activity. These studies suggest that males may decrease consumption of palatable diets in response to physical activity through a potential opioid related habituation mechanism. Conversely, females may undergo an alterative response to physical activity, resulting in an increased consumption of palatable diets. This may occur through a potential opioid related sensitization mechanism. The second study included selectively bred rats to further explore biological factors related to motivation that may arbitrate the physiological and behavioral adaptations in response to physical activity.