Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Division of Sensory Physiology, Development Center for Five-Sense Devices, Kyushu University, Fukuoka 819-0395, Japan.
Nutrients. 2019 Sep 19;11(9):2251. doi: 10.3390/nu11092251.
The systemic renin-angiotensin system (RAS) is an important regulator of body fluid and sodium homeostasis. Angiotensin II (AngII) is a key active product of the RAS. We previously revealed that circulating AngII suppresses amiloride-sensitive salt taste responses and enhances the responses to sweet compounds via the AngII type 1 receptor (AT1) expressed in taste cells. However, the molecular mechanisms underlying the modulation of taste function by AngII remain uncharacterized. Here we examined the expression of three RAS components, namely renin, angiotensinogen, and angiotensin-converting enzyme-1 (ACE1), in mouse taste tissues. We found that all three RAS components were present in the taste buds of fungiform and circumvallate papillae and co-expressed with αENaC (epithelial sodium channel α-subunit, a salt taste receptor) or T1R3 (taste receptor type 1 member 3, a sweet taste receptor component). Water-deprived mice exhibited significantly increased levels of renin expression in taste cells ( < 0.05). These results indicate the existence of a local RAS in the taste organ and suggest that taste function may be regulated by both locally-produced and circulating AngII. Such integrated modulation of peripheral taste sensitivity by AngII may play an important role in sodium/calorie homeostasis.
全身肾素-血管紧张素系统（RAS）是体液和钠稳态的重要调节剂。血管紧张素 II（AngII）是 RAS 的关键活性产物。我们之前的研究表明，循环中的 AngII 通过表达于味觉细胞的血管紧张素 II 型 1 受体（AT1）抑制阿米洛利敏感的盐味觉反应，并增强对甜味化合物的反应。然而，AngII 调节味觉功能的分子机制尚不清楚。在这里，我们检查了三种 RAS 成分（肾素、血管紧张素原和血管紧张素转换酶 1（ACE1）在小鼠味觉组织中的表达。我们发现，这三种 RAS 成分都存在于菌状乳头和轮廓乳头的味蕾中，并与αENaC（上皮钠通道α亚基，盐味觉受体）或 T1R3（味觉受体类型 1 成员 3，甜味受体成分）共表达。缺水的小鼠味觉细胞中的肾素表达水平显著增加（<0.05）。这些结果表明味觉器官中存在局部 RAS，并提示味觉功能可能受到局部产生和循环 AngII 的调节。AngII 对外周味觉敏感性的这种综合调节可能在钠/卡路里稳态中发挥重要作用。
