Effect of taste stimulus on the pharyngolaryngeal swallowing in humans - Does swallowing reflex facilitated by sour taste protect the respiratory tract from gastric acid? -.

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K09389
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Hyogo Medical University
• Principal Investigator: Nin Tomomi 兵庫医科大学, 医学部, 講師 (00599483)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 咽頭嚥下 / 酸味溶液 / 咽喉頭逆流 / 味蕾

Outline of Final Research Achievements

In addition to the tongue, taste buds can be found in the pharyngeal and laryngeal epithelium. However, these structures may not play a role in obtaining taste information. In order to ascertain the role of taste chemoreceptors in the pharyngolarynx, experiments to research the effects of taste stimulation of the pharyngolarynx on spontaneous swallowing and saliva flow were performed.
Swallowing latency time was found to be significantly shorter with application of sour taste compared to that with salt taste. No significant difference in saliva flow was seen among test solutions applied into pharyngolarynx in subjects who did not perceive any taste sensation in each test solution.
Sour taste applied to the pharynx promoted swallowing reflex, without taste perception and increased saliva flow, indicating that facilitation of pharyngeal swallowing by sour taste may protect the pharyngolarynx and respiratory tract from retrograde flow of gastric acid by reflexive swallowing.

Free Research Field

味覚

Academic Significance and Societal Importance of the Research Achievements

現在まで、舌における味覚認知や味覚の役割など報告はみられるものの、咽喉頭における化学受容器の役割を検討した報告は少ない。酸味はもともと唾液分泌とともに嚥下反射を惹起させることが知られており、嚥下障害患者に対する対応として推奨されているが、咽喉頭における酸味の役割を示した報告はほとんどない。今回は酸味刺激に対して咽頭嚥下に限局して検討したところ、有意に咽頭嚥下反射が促進されたことにより、胃酸の咽喉頭逆流を防止する働きについての可能性が示唆された。日常診療においても咽喉頭逆流症が様々な症状を起こしていることより今後、酸刺激を用いた対応や予防などにつなげていきたい。