Effect of exercise, exercise withdrawal, and continued regular exercise on excitability and long-term potentiation in the dentate gyrus of hippocampus

Abstract

Exercise mediates beneficial effects on the brain function and neural health, particularly in the hippocampus as the main area of memory. The hippocampus is a structure involved in exercise, which can improve synaptic plasticity and long-term potentiation (LTP). The present study investigated the effect of exercise, exercise withdrawal, and continued regular exercise on excitability and long-term potentiation in the dentate gyrus (DG) of hippocampus. Fifty male Wistar rats were randomly allocated to the five control, sham, exercise, exercise withdrawal, and continued regular exercise treatments. The experimental animals were forced to run on a treadmill one hour a day at a speed of 20-21 m/min over the two experimental periods of 21 and 42 days. While stimulating the medial perforant pathway, input output (I/O) functions and LTP were recorded from the DG to evaluate synaptic potency and plasticity. The relevant responses in the DG were evaluated in all the groups from the slope and PS amplitude of the fEPSP. Results showed that the 21 day exercise treatment increased both the responsiveness and LTP in the DG of hippocampus. A 21 day withdrawal period after the exercise impaired the beneficial effects of the exercise, indicating the reversibility of these exercise-related hippocampal changes. Significant enhancements were also observed in cell responsiveness and LTP with the continued regular exercise (42 day) treatment.