BACKGROUND/AIMS: Amino acids have many physiological activities. We report the correlation between gastric emptying and gastric adaptive relaxation using tryptophan and amino acids with a straight alkyl chain, hydroxylated chain, and branched chain. Here we sought to further clarify the correlation between gastric emptying and gastric adaptive relaxation by using other amino acids. METHODS: In Sprague-Dawley rats, gastric emptying was evaluated by a breath test using [1-¹³C] acetic acid. The expired ¹³CO₂ pattern, T(max), C(max), and AUC(120min) values were used as evaluation items. Gastric adaptive relaxation was evaluated in a barostat experiment. Individual amino acids (1 g/kg) were administered orally 30 minutes before each breath test or barostat test. RESULTS: L-phenylalanine and L-tyrosine did not influence gastric emptying. All other amino acids, ie, L-proline, L-histidine, L-cysteine, L-methionine, L-aspartic acid, L-glutamic acid, L-asparagine, L-arginine, L-glutamine, and L-lysine significantly delayed and inhibited gastric emptying. L-Cysteine and L-aspartic acid significantly enhanced and L-methionine and L-glutamine significantly inhibited gastric adaptive relaxation. L-Phenylalanine moved the balloon toward the antrum, suggesting strong contraction of the fundus. T(max) showed a significant positive correlation (r = 0.709), and C(max) and AUC(120min) each showed negative correlations (r = 0.613 and 0.667, respectively) with gastric adaptive relaxation. CONCLUSION: From the above findings, it was found that a close correlation exists between gastric emptying and adaptive relaxation, suggesting that enhanced gastric adaptive relaxation inhibits gastric emptying.
Acetic Acid ; Amino Acids* ; Animals ; Arginine ; Asparagine ; Aspartic Acid ; Breath Tests ; Cysteine ; Gastric Emptying* ; Glutamic Acid ; Glutamine ; Histidine ; Lysine ; Methionine ; Phenylalanine ; Proline ; Rats ; Rats, Sprague-Dawley ; Relaxation* ; Tryptophan ; Tyrosine

In this study, we implemented a health education course, comprising lectures, cooking lessons, and group discussions for household cooks, that addressed the need for continued reduction of table salt intake and evaluated the effects from participants’ narratives. After the health education course, participants reported continuing to make the following efforts: planning dishes that have a milder yet still delicious taste, evaluating the amount of salt, refraining from highly salty dishes, and continuing to reduce salt use when cooking. The reasons participants continued to reduce table salt use included wanting to live a healthy life, understanding how to reduce salt in dishes, learning to reduce salt consumption, learning to check the amount of salt in dishes, learning that low-salt cooking is easy, learning that unseasoned dishes can be delicious, and feeling the benefits of reduced salt intake. Participants learned that low-salt cooking is easy and how to determine the amount of salt from set values, which were effective for their continued reduction of salt intake. Moreover, our study shows that continuous support is important until individuals become accustomed to milder tastes.