| Project/Area Number |
21792062
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthodontic/Pediatric dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
YABUSHITA Tadachika Tokyo Medical and Dental University, 歯学部, 非常勤講師 (40420260)
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| Project Period (FY) |
2009 – 2010
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| Project Status |
Completed (Fiscal Year 2010)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2010: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2009: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
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| Keywords | 小脳 / 液状飼料 / 顎関節侵害受容器 / 閉口筋筋紡錘 / 電気生理 / フィードバック / 軟食化 / 学習 / 咀嚼運動 / 長期抑圧 |
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| Research Abstract |
Recently, it has been shown that prolonged feeding on liquid diet after being weaned impedes functional development and leads to immature mastication in growing rats. Since jaw muscle spindles play an important role in the control of jaw movements during normal masticatory function, in this study we investigated the effect of prolonged feeding on liquid diet after being weaned on the functional development of jaw-closing muscle spindles in growing rats. Soon after weaning, 40 female Wistar rats were divided into two equal groups. The control group fed on solid diet and the experimental group fed on liquid diet. At 5, 7, 9 and 11 weeks, the rats were anesthetized and the response of the masseter muscle spindles to ramp-and-hold jaw stretches were recorded from the mesencephalic trigeminal nucleus. In the experimental groups, both the dynamic and the static indices were significantly lower than those of the control groups at the age of 5, 7, 9 and 11 weeks old. There was no significant change within the same group during the experimental period in both indices. These results suggest that long-term masticatory functional change due to liquid diet feeding may impede maturation of the functional properties of jaw-closing muscle spindles, leading to immature mastication in growing rats.
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