Teramoto Hidemi, Shimizu Toshiyasu, Yogo Hideto, Nishimiya Yuuta, Hori Shinji, Kosugi Takashi, Nakayama Shinsuke
Department of Internal Medicine, Kojin Hospital, Nagoya, 463-8503, Japan.
R'Tech Corporation, Hamamatsu, 431-2103, Japan.
Physiol Rep. 2014 Jan 6;2(1):e00187. doi: 10.1002/phy2.187. eCollection 2014 Jan 1.
Glutamate is thought to serve as a special signal for gut functions. We investigated the effects of monosodium l-glutamate (MSG) on gastric emptying and duodenal motility. Ten healthy male volunteers underwent rapid magnetic resonance imaging (MRI) of the abdomen. Coronal images were successively acquired after ingestion of liquid meal (200 kcal in 200 mL: 9 g protein, 28.4 g carbohydrate, 5.6 g fat, 370 mg Na(+)) with and without 0.5% MSG. During the acquisition of MRI, participants breathed freely. In all participants, the gastric residual volume gradually decreased to 80.1 ± 14.2% without MSG and to 75.9 ± 14.3% with MSG after 60 min (P = 0.45 between the groups, n = 10). In two of 10 participants, gastric emptying slowed down significantly, whereas in the remaining eight participants, gastric residual volume decreased to 84.0 ± 13.1% without MSG, and to 73.0 ± 14.6% with MSG after 60 min (P = 0.015, n = 8). There was no difference in the shape of the stomach between groups. In four of the eight participants responding positively to MSG, the duodenum wall was sufficiently identified to quantify the motions. The inclusion of MSG enhanced duodenal motility, judging from changes in (1) the magnitude of the duodenal area, (2) the center of gravity, and (3) the mean velocity of the wall motions. The third parameter most significantly indicated the excitatory effect of l-glutamate on duodenum motility (~ three- to sevenfold increase during 60 min, P < 0.05, n = 4). These results suggest that MSG accelerates gastric emptying by facilitating duodenal motility, at least in subjects with positive responses to MSG.
谷氨酸被认为是肠道功能的一种特殊信号。我们研究了L-谷氨酸钠（MSG）对胃排空和十二指肠运动的影响。10名健康男性志愿者接受了腹部快速磁共振成像（MRI）检查。在摄入含0.5% MSG和不含0.5% MSG的流食（200 mL含200千卡：9克蛋白质、28.4克碳水化合物、5.6克脂肪、370毫克钠）后，连续获取冠状面图像。在MRI采集过程中，参与者自由呼吸。在所有参与者中，60分钟后，不含MSG时胃残余容积逐渐降至80.1±14.2%，含MSG时降至75.9±14.3%（两组间P = 0.45，n = 10）。10名参与者中有2名胃排空显著减慢，而其余8名参与者中，60分钟后不含MSG时胃残余容积降至84.0±13.1%，含MSG时降至73.0±14.6%（P = 0.015，n = 8）。两组间胃的形状无差异。在对MSG反应呈阳性的8名参与者中，有4名十二指肠壁能够清晰识别以量化运动。从（1）十二指肠面积大小、（2）重心以及（3）壁运动平均速度的变化判断，添加MSG增强了十二指肠运动。第三个参数最显著地表明了L-谷氨酸对十二指肠运动的兴奋作用（60分钟内增加约三至七倍，P < 0.05，n = 4）。这些结果表明，至少在对MSG有阳性反应的受试者中，MSG通过促进十二指肠运动来加速胃排空。
