The Bulletín of Kanagawa Dental College

Vol. 37 No. 1       MARCH- 2009

ISSN: 0385-1443      UBIC: 65

ABSTRACT

This study presents a review of a role of chewing in ameliorating the stress-attenuated hippocampal memory process. The hypothalamic-pituitary-adrenal (HPA) axis is activated by stressful stimuli and the secretion of stress hormones is induced from the adrenal cortex. These stress responses are essential to help restore homeostasis during and after stressful experiences, however, prolonged exposure to excessive stress hormones adversely impairs the normal functions of the body and the brain. One of the detrimental effects of stress hormones on cognitive function is to suppress learning and memory processes in the hippocampus. We recently discovered that stress-attenuated hippocampal synaptic plasticity, a cellular mechanism of the memory process, is counteracted when rats respond behaviorally to stress by chewing a wooden stick. Furthermore, in these rats, the plasma concentration of adrenocorticotropic hormone returned to its resting level immediately following exposure to stress, suggesting the possibility that chewing may suppress the prolonged activation of the HPA axis under stressful stimulation. These results support chewing as a good strategy to cope with severe stress, and suggest that it might be a promising and easily performed method of preventing stress-induced dysmnesia by maintaining the hippocampal memory process. Key words: Hippocampus / Chewing / Synaptic plasticity / Corticosterone / Stress / NMDA receptor.

| Volver |