Motor and Cognitive Functions in Aging C57BL/6 Mice: Association with Activity of the Monoaminergic Systems in the Cerebellum and Frontal Cortex

The activity in the open field, short- and long-term memory in the novel object recognition test, and gait features were evaluated in 6- and 12-month-old male C57BL/6 mice. The levels of norepinephrine, dopamine, serotonin, and their metabolites were determined in the cerebellum and frontal cortex. In the observed age range, a decrease in locomotion speed, impairment of gait initiation and stability, and long-term memory deficit were revealed. In the cerebral cortex, reduced levels of dopamine and its metabolites and accelerated metabolism of all neurotransmitters under study were found. In the cerebellum, the content of all studied monoamines was elevated, while dopamine metabolism was decelerated. Analysis of correlations between the neurochemical and behavioral parameters showed that the mechanisms of compensation of brain functions during the early aging may be associated with an increase in activity of the monoaminergic systems in the cerebellum.