ABSTRACT
In this study, we investigated the effects of treadmill exercise on hippocampal levels of calcium-binding proteins - calbindin D-28k (CB), calretinin (CR) and parvalbumin (PV) - using immunohistochemistry and Western blot analysis. At 6 weeks of age, male Wistar rats were put on a treadmill with or without running for 1 h/day/5 consecutive days at a pace of 22 m/min for a period of 5 weeks. In sedentary and exercise groups, CB immunoreaction was detected in granule cells of the dentate gyrus, mossy fibers, and CA1 pyramidal cells. In addition, CB immunoreaction was observed in interneurons of the CA1-3 region. Exercise significantly increased CB immunoreactivity in dentate granule cells, CA1 pyramidal cells and CA1-3 interneurons. CR immunoreaction was mainly observed in interneurons of the dentate gyrus and CA1-3 regions. Similar number of CR-immunoreactive neurons was observed in the exercise and sedentary groups. PV immunoreaction was detected in interneurons of the dentate gyrus and CA1-3 regions. PVimmunoreactive fibers were significantly increased in all regions of the hippocampus in the exercise group, as compared to the sedentary group. Similar to the immunohistochemical findings, protein levels of CB and PV were also increased in the exercise group compared to the sedentary group. These increases in CB and PV in the hippocampus may induce neuronal plasticity after treadmill exercise and may be related to the enhancement of synaptic plasticity in the hippocampus by exercise.