Acute bouts of exercise have been shown to produce transient increases in regional cerebral glucose utilization, oxygen uptake, and cerebral blood flow in the motor cortex, striatum, and hippocampus. To test whether or not exercise causes these regions to undergo an increase in the capacity for oxidative metabolism, cytochrome oxidase (COX) reactivity was measured in these brain areas. The activity of COX, is coupled to the production of ATP, the source of energy used for neural communication. Alterations in the amount of COX are an indication of long-term plasticity in metabolic capacity. McCloskey, Adamo and Anderson (2001) demonstrated that 6 months of voluntary wheel running in rats increased the capacity for oxidative metabolism in regions of the motor cortex and striatum that contain limb movement representations, but not in the hippocampus or striatal regions known to receive face-related input. The purpose of the present study was to determine whether or not a shorter exposure to exercise wheels, 21 days, could also alter COX reactivity in the same brain structures. Two month old, female Long-Evans hooded rats were randomly assigned to a control (n=8) or exercise (n=8) condition. Like the earlier study, exercising rats had running wheels attached to their home cages, but for only 21 days, whereas control rats had identical cages without wheels. After the training period, COX reactivity was measured using COX histochemical methods and optical densitometry. Standards were incorporated into the design so that we could assure that COX reactivity was linearly related to the amount of COX in tissue. Optical density measures from the motor cortex, striatum, hippocampus, medial septum and nucleus accumbens are currently being collected and analyzed with a one-way analysis of covariance.

This project was supported by MH62075 and a Simons Fellowship.