The enhancing effect of peripheral physical activity on spatial memory by elevating central neurotrophic factor and synaptic plasticity-related proteins in the hippocampus of adolescent rats

Abstract

Investigation of spatial memory entails studying the process for encoding and retrieving spatial information in working memory that is required for animal and human survival. Synaptic plasticity in the hippocampus is necessary for working memory. Physical activity stimulates the N-methyl-D-aspartate receptor (NMDAR) and subsequently increases NR2A or NR2B subunits of NMDAR-enabling synaptic plasticity in the hippocampus. Reduction of NMDAR and the postsynaptic density (PSD)-95 protein can be found in learning and memory impairment. An increasing amount of evidence has shown that peripheral physical activity has an enhancing effect on learning and memory and elevates the expression of brain-derived neurotrophic factor (BDNF). However, the mechanisms of physical activity that improve working memory have not been fully understood. In the current study, we study the potential effects of peripheral physical activity on spatial memory and synaptic plasticity-related proteins. Physical activity was performed by having the rats do voluntary wheel running throughout P25-P40. The Morris water maze task was performed on P40 for 6 days to study spatial memory. The hippocampal protein expression was ascertained by Western blot analysis. We found that physical activity enhanced spatial memory and BDNF, PSD-95, NR2A, and NR2B levels in the hippocampus. Physical activity can be effective in improving the central synaptic plasticity-related proteins that are essential for learning and memory. Peripheral physical activity is a promising candidate for further investigation as a potential treatment for learning and memory impairment.