New remedy for dry mouth using the gustatory-salivary reflex

Patients with dry mouth are increasing in Japan due to the country's super-aging society and stressful modern society. Dry mouth affects quality of life, including diffculty with speech or swallowing, and also causes aspiration pneumonia and, respiratory infection. Moreover, dry mouth closely relates to taste dysfunction, resulting in malnutrition, a common risk of nursing care in the elderly. Against these backgrounds, dry mouth has recently been a target of social concern. Drugs for dry mouth such as M3, a muscarinic agonist, have been widely used: however, these drugs have serious side effects, such as vomiting, sweating and/or digestive disorders. We examined the gustatory-salivary reflex to explore a remedy for dry mouth. We have demonstrated that umami stimulation increases saliva from both minor- and major salivary-glands, and that the effect is longer-lasting than with the other four basic tastes. Stimulating the umami response could therefore be a safe and useful remedy for dry mouth.