Meeting Abstract
3.5 Saturday, Jan. 4 09:00 Influence of corticosterone on growth, home-cage activity, wheel running, and maximal oxygen consumption in replicate lines of house mice selectively bred for high voluntary wheel-running behavior SINGLETON, J. M.*; GARLAND, T.; University of California, Riverside; University of California, Riverside jsing014@ucr.edu
Corticosterone, chiefly referred to as a “stress hormone,” impacts a surprising variety of organismal traits, including skeletal growth, cognition, and motivation. Hence, changes in corticosterone levels may impact multiple aspects of locomotor behavior, including both motivation and physical abilities. Previous rodent studies have found that altering circulating corticosterone levels can affect activity levels or induce a depressive state, depending on dosage and other factors. We have used a long-term artificial selection experiment to examine the evolution of high levels of voluntary wheel-running behavior in laboratory house mice. As compared with four non-selected control (C) lines, the four replicate High Runner (HR) lines are smaller in body size, run ~3-fold more on wheels on a daily basis, have higher home-cage activity when deprived of wheels, and have higher maximal oxygen consumption (VO2max) and basal circulating corticosterone levels. To examine further the role of corticosterone in locomotion, we administered 50 µg/ml in the drinking water of HR and C male mice from weaning to seven weeks of age. Mice were then tested for wheel running and maximal oxygen consumption. Corticosterone administration reduced growth rate and body mass-adjusted VO2max of both HR and C mice. It did not affect wheel running of C mice, but decreased that of the HR lines. Previous studies show that HR but not C mice sometimes run voluntarily at or near their maximal aerobic speed, so the present results suggest that corticosterone can impact wheel running via changes in VO2max when animals are motivated to run voluntarily near their aerobic limits. Supported by NSF IOS-11212732.
