OSNC10: Mastication Promotes Expression of Some Memory-Related Genes in the Cerebral Cortex.

Purpose: It has been reported that mastication promotes function of learning and memory via the trigeminal nerve and blood vessels. BDNF promotes synapse connections between neurons, while CREB is a transcription factor for certain proteins related to memory including BDNF. Apo E is an apolipoprotein that plays a role in the transportation of cholesterol, and it is known that functional disorder of Apo E affects cognitive function. We examined whether certain genes that are responsible for learning and memory were more strongly expressed after mastication. Materials and Methods: After starvation for 24 hours, 20 Wister rats were divided into two groups. One group was given 0.2 cal/kg of solid food (solid feed group) that rats should masticate because of hard pellet and the other was given 0.2 cal/kg of liquid food (liquid feed group) that rats only swallowed without mastication. The solid and 1iquid foods contained identical nutrition. After euthanasia, the whole cerebral cortex was removed, and mRNA was extracted. Relative expression levels of BDNF, APO E, and CREB in the two groups were measured by real time RT-PCR. Results: Expression levels of BDNF and CREB were higher in the solid feed group than in the liquid feed group. Expression of APO E was comparable in the two groups. Conclusion: Our results suggest that mastication of solid food promotes expression of BDNF and CREB. Mastication may be useful for learning and memory via a mechanism involving BDNF and CREB.