Yamashita Atsuko, Kondo Kaori, Kunishima Yoshimi, Iseki Sachiko, Kondo Takashi, Ota Masato S
Laboratory of Anatomy, Physiology and Food Biological Science, Department of Food and Nutrition, Japan Women's University, Bunkyo-ku, Tokyo, Japan.
Laboratory for Developmental Genetics, RIKEN-IMS, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
Biochem Biophys Res Commun. 2018 Jan 22;495(4):2579-2583. doi: 10.1016/j.bbrc.2017.12.126. Epub 2017 Dec 24.
Bitter taste avoidance behavior (BAB) plays a fundamental role in the avoidance of toxic substances with a bitter taste. However, the molecular basis underlying the development of BAB is unknown. To study critical developmental events by which taste buds turn into functional organs with BAB, we investigated the early phase development of BAB in postnatal mice in response to bitter-tasting compounds, such as quinine and thiamine. Postnatal mice started to exhibit BAB for thiamine and quinine at postnatal day 5 (PD5) and PD7, respectively. Histological analyses of taste buds revealed the formation of microvilli in the taste pores starting at PD5 and the localization of type 2 taste receptor 119 (TAS2R119) at the microvilli at PD6. Treatment of the tongue epithelium with cytochalasin D (CytD), which disturbs ACTIN polymerization in the microvilli, resulted in the loss of TAS2R119 localization at the microvilli and the loss of BAB for quinine and thiamine. The release of ATP from the circumvallate papillae tissue due to taste stimuli was also declined following CytD treatment. These results suggest that the localization of TAS2R119 at the microvilli of taste pores is critical for the initiation of BAB.
苦味回避行为（BAB）在避免摄入有苦味的有毒物质方面起着重要作用。然而，BAB发育的分子基础尚不清楚。为了研究味蕾如何发育成为具有BAB功能的器官这一关键发育事件，我们研究了出生后小鼠对奎宁和硫胺素等苦味化合物的BAB早期发育情况。出生后小鼠分别在出生后第5天（PD5）和第7天（PD7）开始表现出对硫胺素和奎宁的BAB。味蕾的组织学分析显示，从PD5开始，味孔中形成微绒毛，在PD6时，2型味觉受体119（TAS2R119）定位于微绒毛。用细胞松弛素D（CytD）处理舌上皮，它会干扰微绒毛中的肌动蛋白聚合，导致TAS2R119在微绒毛中的定位丧失，以及对奎宁和硫胺素的BAB丧失。CytD处理后，由于味觉刺激导致的轮廓乳头组织中ATP的释放也减少。这些结果表明，TAS2R119在味孔微绒毛中的定位对于BAB的启动至关重要。
