1 0 0 0 噛んでボケは予防できるか: 咀嚼機能不全と脳の高次精神機能
- 著者
- 小野塚 実 渡邊 和子 藤田 雅文 斉藤 滋
- 出版者
- Japanese Society for Mastication Science and Health Promotion
- 雑誌
- 日本咀嚼学会雑誌 (ISSN:09178090)
- 巻号頁・発行日
- vol.11, no.2, pp.109-116, 2002
In recent years, dysfunctional mastication, which is resulted from decreased number of residual teeth, use of unsuitable dentures, or reduced biting force, has been suggested to be related to the development of senile dementia. Recently, in senescence-accelerated mice (SAMP8 mice), we have studied the involvement of masticatory dysfunction, e.g. cut off of the upper molar teeth, extract of the upper molar teeth, or cut of the one side of the masseteric nerve, in the senile process of learning and memory. First, we found that conditions of such dysfunctional mastication progress age-related deficits in spatial memory storage in a water maze test and in hippocampal pyramidal neurons. These pathological phenomena were begun to occur in middle-aged mice, suggesting that masticatory disfunction may lead to hippocampal pathological changes in the elderly.<BR>Second, it was found that cutting off the upper molar teeth causes a reduction in the protein product, Fos, of the immediate early gene, c-fos, in the hippocampal CA1 subfield. Interestingly, both the suppression of memory storage ability and the decrease in Fos induction in this subfield induced by cutting off the upper molars were considerably improved by restoring the lost molars with artificial crowns, suggesting that normal mastication may be an important factor in maintaining normal hippocampal activities.<BR>Third, in biochemical and immunohistochemical studies examining the effect of masticatory dysfunction on age-related changes in the septohippocampal cholinergic system, we have foundthat, in aged mice, masticatory disfunction induces a decrease in acetylcholine release and choline acetyltransferase activity in the hippocampus and a reduction in the number of choline acetyltransferase-immunopositive neurons in the medial septal nucleus. However, these effects were not seen in young mice, implying that dysfunctional mastication may enhance an age-related decline in the septohippocampal cholinergic system.<BR>Finally, stress may be linked to hippocampal pathological changes induced by masticatory dysfunction. As expected, in the aged mice, conditions under masticatory dysfunction brought about a chronic elevation in plasma corticosterone levels. However, pretreatment with metyrapone, which suppresses the stress-induced rise in this hormone levels, prevented dysfunctional mastication-induced increase in plasma corticosterone levels, reduction in hippocampal pyramidal neuron numbers, and impairment of spatial memory. These findings suggest a link between the masticatory dysfunction and the glucocorticoid response, which may be involved in deficits in learning and memory and hippocampal neuronal death.<BR>In conclusion, we suggest that normal mastication may be effective in preventing senile dementia by maintaining normal function in the hippocampus, which is the most sensitive region to aging processes.
1 0 0 0 QOLとしての咀嚼器官 : ストレスとの関連性
- 著者
- 富田 美穂子 斉藤 滋 小野塚 実
- 雑誌
- 日本咀嚼学会雑誌 : 咀嚼と健康 = Journal of Japanese Society for Masticatory Science and Health Promotion (ISSN:09178090)
- 巻号頁・発行日
- vol.12, no.1, pp.3-10, 2002-12-30
- 参考文献数
- 40
- 被引用文献数
- 4
1 0 0 0 咬合不全とストレス
1 0 0 0 噛んでボケは予防できるか : 咀嚼機能不全と脳の高次精神機能
- 著者
- 小野塚 実 渡邊 和子 藤田 雅文 斉藤 滋
- 雑誌
- 日本咀嚼学会雑誌 : 咀嚼と健康 = Journal of Japanese Society for Masticatory Science and Health Promotion (ISSN:09178090)
- 巻号頁・発行日
- vol.11, no.2, pp.109-116, 2002-03-30
- 被引用文献数
- 7 5
1 0 0 0 OA 噛んでボケは予防できるか: 咀嚼機能不全と脳の高次精神機能
- 著者
- 小野塚 実 渡邊 和子 藤田 雅文 斉藤 滋
- 出版者
- Japanese Society for Mastication Science and Health Promotion
- 雑誌
- 日本咀嚼学会雑誌 (ISSN:09178090)
- 巻号頁・発行日
- vol.11, no.2, pp.109-116, 2002-03-30 (Released:2011-07-05)
- 参考文献数
- 26
- 被引用文献数
- 2
In recent years, dysfunctional mastication, which is resulted from decreased number of residual teeth, use of unsuitable dentures, or reduced biting force, has been suggested to be related to the development of senile dementia. Recently, in senescence-accelerated mice (SAMP8 mice), we have studied the involvement of masticatory dysfunction, e.g. cut off of the upper molar teeth, extract of the upper molar teeth, or cut of the one side of the masseteric nerve, in the senile process of learning and memory. First, we found that conditions of such dysfunctional mastication progress age-related deficits in spatial memory storage in a water maze test and in hippocampal pyramidal neurons. These pathological phenomena were begun to occur in middle-aged mice, suggesting that masticatory disfunction may lead to hippocampal pathological changes in the elderly.Second, it was found that cutting off the upper molar teeth causes a reduction in the protein product, Fos, of the immediate early gene, c-fos, in the hippocampal CA1 subfield. Interestingly, both the suppression of memory storage ability and the decrease in Fos induction in this subfield induced by cutting off the upper molars were considerably improved by restoring the lost molars with artificial crowns, suggesting that normal mastication may be an important factor in maintaining normal hippocampal activities.Third, in biochemical and immunohistochemical studies examining the effect of masticatory dysfunction on age-related changes in the septohippocampal cholinergic system, we have foundthat, in aged mice, masticatory disfunction induces a decrease in acetylcholine release and choline acetyltransferase activity in the hippocampus and a reduction in the number of choline acetyltransferase-immunopositive neurons in the medial septal nucleus. However, these effects were not seen in young mice, implying that dysfunctional mastication may enhance an age-related decline in the septohippocampal cholinergic system.Finally, stress may be linked to hippocampal pathological changes induced by masticatory dysfunction. As expected, in the aged mice, conditions under masticatory dysfunction brought about a chronic elevation in plasma corticosterone levels. However, pretreatment with metyrapone, which suppresses the stress-induced rise in this hormone levels, prevented dysfunctional mastication-induced increase in plasma corticosterone levels, reduction in hippocampal pyramidal neuron numbers, and impairment of spatial memory. These findings suggest a link between the masticatory dysfunction and the glucocorticoid response, which may be involved in deficits in learning and memory and hippocampal neuronal death.In conclusion, we suggest that normal mastication may be effective in preventing senile dementia by maintaining normal function in the hippocampus, which is the most sensitive region to aging processes.
本研究の目的は、研究-1:偏位性咀嚼習癖を持つ患者の聴力変化の機構を明らかにするため、コットンロール噛みしめ時の聴性誘発脳磁場(AFEs)を定量的に比較検討すること。研究-2:歯科診療所に来院した患者の偏咀嚼と聴力値との関連性を疫学的に検討すること、である。本年度に得られた新しい知見は、研究-1:申請者らの開発した最大咬合圧の40%以下までのコットンロール噛みしめの条件でAFEs測定を行う方法を用いて研究1を行い、以下の結果を得た。噛みしめ時のAEFs応答は、左右側音刺激に対するAEFs応答はすべての被験者で低下しており、特に噛みしめ側と同じ聴覚野の応答に有意な差が認められた。噛みしめが聴覚野応答を低下させる理由として1)顎関節の偏位による形態的変化、2)中耳および内耳の神経支配への影響、あるいは3)gate controlによる中枢での抑制が考察された。本研究は、コットンロール噛みしめが、聴覚誘発磁場に影響を与えていることを客観的に示すものである。また、本研究に用いた方法は、噛みしめの聴覚応答をはじめとする体性感覚に影響を与えていることを実験的に検討する方法として有用であることを示している。研究2:オージオグラムの咬合咀嚼機能の動的評価への応用について20症例による検討を行った。すなわち、プレスケールおよびシロナソアナライジングシステムによる咬合咀嚼機能の評価にオージオグラムを加えることの有効性を評価しました。その結果、質問紙調査、口腔内診査、プレスケール、咀嚼運動ならびに作業用模型による分析にオージオグラムの周波数別の聴力低下パターン評価を組み合わせることにより、咬合咀嚼運動のより正確な動的評価が可能であることが示された。