Effects of treadmill training on motor performance and extracellular glutamate level in striatum in rats with or without transient middle cerebral artery occlusion

Glutamate transmission is essential for learning and memory. Several studies have shown that exercise can up-regulate the expression of brain-derived neurotrophic factor (BDNF) in normal brain, thus enhancing glutamate release through the synaptic-associated protein synapsin I in vitro. The aim of this study was to investigate the effects of treadmill training on the release of these factors in the striatum and on the motor function in both normal and brain-ischemic rats. Rats were randomly assigned to normal and brain-ischemic groups. Those in the brain-ischemic group underwent middle cerebral artery occlusion (MCAO) for 1 h. Fifty percent of the rats in each group underwent treadmill training for 14 days. The rest remained relatively inactive for 14 days and served as the control groups. Motor function was assessed by performing three motor tests (foot-fault-placing, parallel-bar-crossing, and ladder-climbing tests). Our data showed that after treadmill training, motor function improved significantly in both normal and brain-ischemic rats when compared with the corresponding controls. The levels of glutamate, BDNF, and p-synapsin I were also up-regulated by treadmill training. These results suggested that the overall responses to treadmill training were similar in both normal and brain-ischemic rats. The beneficial effects of treadmill training might be partly due to the involvement of glutamate in neuronal activity in both brain-ischemic and normal rats.