Different Exercise Time on 5-HT and Anxiety-like Behavior in the Rat With Vascular Dementia.

Abstract

Previous studies have demonstrated that pre-exercise suppresses anxiety-like behavior, but the effects of different exercise times on vascular dementia induced anxiety-like behavior have not been well investigated. The present study aims to investigate the underlying neurochemical mechanism of different pre-vascular-dementia exercise times on 5-HT and anxiety-like behavior in rats with vascular dementia. 32 Sprague-Dawley (SD) rats were randomly divided into 4 groups: sham group (S group, n = 8), vascular dementia group (VD group, n = 8), 1-week physical exercise and vascular dementia group (1WVD group, n = 8), and 4weeks physical exercise and vascular dementia group (4WVD group, n = 8). 1week and 4weeks of voluntary wheel running were used as pre-exercise training. The vascular dementia model was established by bilateral common carotid arteries occlusion (BCCAo) for 1week. But bilateral common carotid arteries were not ligated in the sham group. The level of hippocampal 5-HT was detected with in vivo microdialysis coupled with high-performance liquid chromatography (MD-HPLC). Elevated plus maze (EPM), open field (OF), and light/dark box test were used to test anxiety-like behavior. Compared with the C group, the hippocampal 5-HT was significantly decreased in the VD group after 1week of ligated operation. The hippocampal 5-HT levels in 1WVD and 4WVD groups were substantially higher than the level in the VD group. The hippocampal 5-HT level has no significant difference among C, 1WVD, and 4WVD. Behavioral data suggested that the rats in the VD group developed obvious anxiety-like behavior after 1week of ligation surgery. Still, the rats in 1WVD and 4WVD groups did not show significant anxiety-like behavior. Both 1week and 4weeks of voluntary running wheel exercise can inhibit the anxiety-like behavior in rats with vascular dementia by upregulating 5-HT levels in the hippocampus in the VD model.