Int Neurourol J.  2016 Nov;20(Suppl 2):S141-S149. 10.5213/inj.1632738.369.

Treadmill Exercise Improves Memory Function Depending on Circadian Rhythm Changes in Mice

• Hwang DS
• Kwak HB
• Ko IG
• Kim SE
• Jin JJ
• Ji ES
• Choi HH
• Kwon OY

• KMID: 2362507
• DOI: http://doi.org/10.5213/inj.1632738.369

Abstract

PURPOSE
Exercise enhances memory function by increasing neurogenesis in the hippocampus, and circadian rhythms modulate synaptic plasticity in the hippocampus. The circadian rhythm-dependent effects of treadmill exercise on memory function in relation with neurogenesis were investigated using mice.
METHODS
The step-down avoidance test was used to evaluate short-term memory, the 8-arm maze test was used to test spatial learning ability, and 5-bromo-2'-deoxyuridine immunofluorescence was used to assess neurogenesis. Western blotting was also performed to assess levels of synaptic plasticity-associated proteins, such as brain-derived neurotrophic factor, tyrosine kinase receptor B, phosphorylated cAMP response element-binding protein, early growth response protein 1, postsynaptic density protein 95, and growth-associated protein 43. The mice in the treadmill exercise at zeitgeber 1 group started exercising 1 hour after sunrise, the mice in the treadmill exercise at zeitgeber 6 group started exercising 6 hours after sunrise, and the mice in the treadmill exercise at zeitgeber 13 group started exercising 1 hour after sunset. The mice in the exercise groups were forced to run on a motorized treadmill for 30 minutes once a day for 7 weeks.
RESULTS
Treadmill exercise improved short-term memory and spatial learning ability, and increased hippocampal neurogenesis and the expression of synaptic plasticity-associated proteins. These effects of treadmill exercise were stronger in mice that exercised during the day or in the evening than in mice that exercised at dawn.
CONCLUSIONS
Treadmill exercise improved memory function by increasing neurogenesis and the expression of synaptic plasticity-associated proteins. These results suggest that the memory-enhancing effect of treadmill exercise may depend on circadian rhythm changes.

Keyword

Exercise Test; Memory, Short-term; Learning; Neurogenesis; Neuronal Plasticity

MeSH Terms

Animals
Blotting, Western
Brain-Derived Neurotrophic Factor
Circadian Rhythm*
Cyclic AMP Response Element-Binding Protein
Early Growth Response Protein 1
Exercise Test
Fluorescent Antibody Technique
GAP-43 Protein
Hippocampus
Learning
Memory*
Memory, Short-Term
Mice*
Neurogenesis
Neuronal Plasticity
Post-Synaptic Density
Protein-Tyrosine Kinases
Spatial Learning
Brain-Derived Neurotrophic Factor
Cyclic AMP Response Element-Binding Protein
Early Growth Response Protein 1
GAP-43 Protein
Protein-Tyrosine Kinases