A Comparative Study between Masticatory Muscular Activity and Regional Brain Function during Gum Chewing as Measured using a Whole-body Positron Emission Tomography

本研究的目的是以局部能量代谢为指标，研究咀嚼对全身活动的影响。以水为示踪剂，对9名健康志愿者进行了全身正电子发射断层扫描(PET)。用18F-氟代脱氧葡萄糖(FDG)测定了4名受试者咀嚼过程中咀嚼肌和舌肌的能量代谢。结果：(1)与咀嚼有关的肌肉活动中，FDG在舌内肌的积聚最高。在咀嚼肌，尤其是咬肌，FDG的区域摄取异质性被发现。FDG-PET可以一次显示咀嚼肌的相对作用力。我们的结论是，舌头在咀嚼中起着非常重要的作用。(2)咀嚼口香糖后，大鼠全脑rCBF绝对值较安静状态增加15%。区域性增加最明显的是双侧初级感觉运动区。这些结果表明，咀嚼和咀嚼刺激大脑，可能有利于保持我们的心理健康。

The purpose of the study is to investigate the effects of mastication on whole-body activity using regional energy metabolism as a marker. A whole-body positron emission tomography (PET) was carried out using ^<15>O water as a tracer for regional cerebral blood flow (rCBF) in nine normal volunteers. The energy metabolism of masticatory and tongue muscles during chewing was also measured in another four subjects using ^<18>F-fluoro-D-deoxyglucose (FDG). Results : (1) Concerning muscular activity related to mastication, accumulation of FDG was the highest in the intrinsic tongue muscle. Heterogeneous regional uptake of FDG in the masticatory muscles, especially in the masseter muscles was found. FDG-PET could visualize relative workforce of the masticatory muscles at once. We conclude that the tongue plays a very important role in chewing. (2) The whole brain absolute rCBF increased 15% by gum-base chewing compared with the resting condition. Regional increases were most noted in the bilateral primary sensory-motor area. These results suggest that chewing and mastication stimulate brain and may be favorable for keeping our mental health.