Abstract
Purpose: Although a relationship between masticatory function and higher brain function has been reported, its mechanism has not been revealed. Higher brain function, which includes the development of neural circuits and their functional expression after the differentiation and maturation of neurons, the ramification of dendrites and the formation of synapses, involves the synthesis of cholesterol by brain-derived neurotrophic factor. In this study, we evaluated whether solid feed, which requires mastication, is more conducive than liquid feed to the expression of brain-derived neurotrophic factor and its synthesis of cholesterol in rats.
Methods: After rats were raised on solid or liquid feed for eight weeks, the brain tissue was divided into the cerebellum, medulla oblongata, hypothalamus, mesencephalon - hippocampus - corpus striatum, and cerebral cortex. The expression of brain-derived neurotrophic factor was measured by real-time RT-PCR, the receptors for brain-derived neurotrophic factor were immunostained and the total amount of cholesterol was measured.
Results: Rats raised on solid feed had significantly greater expression of brain-derived neurotrophic factor and more receptors for it as well as a greater total amount of cholesterol in cerebral cortex.
Conclusions: This study suggests that mastication affects the synthesis of cholesterol via brain-derived neurotrophic factor involved in learning and memory function.
