Exercise-induced changes in cardiac gene expression and its relation to spatial maze performance.
Cognitive performance is sensitive to both neural and non-neural changes induced by physical activity and inactivity. This study investigated whether access to physical activity outside a standard laboratory animal cage affected cognitive performance as measured by navigation of a spatial maze. It also examined gene expression in heart tissue for genes associated with cardiovascular function given recent reports of cognitive impairment associated with hyperlipidemia. Furthermore, we measured expression of neural-regulatory genes typically expressed in brain, but also found in cardiac tissue. Male Sprague-Dawley rats (n = 72) were separated into three groups having different access to physical activity: none outside a standard cage, twice-weekly physical activity, and every other day exercise on a running wheel. Compared with a sedentary group, spatial maze performance was enhanced in animals that had access to physical activity, either twice-weekly in a large box or every other day on a running wheel. Both the cardiovascular and neural-related genes expressed in the heart were distinguished by access to physical activity. Several genes that are associated with heart rate, cholesterol biosynthesis, blood pressure, and cell adhesion regulation, including GJA1, FDFT1, EDN1, and CD36, differed in animals based on access to physical activity. Neural-related genes expressed in cardiac tissue associated with neurite outgrowth, neuroplasticity, and neurogenesis including RTN4, HOMER2, ACTB, NCDN, KIF5B, and HMGB2, were expressed differently among the three groups. Significant shifts in ten cardiovascular and neural-related gene expressions in cardiac tissue were associated with physical activity and may have influenced learning and performance on a spatial maze.