Cheled-Shoval Shira, Behrens Maik, Korb Ayelet, Di Pizio Antonella, Meyerhof Wolfgang, Uni Zehava, Niv Masha Y
Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
The Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Molecules. 2017 May 17;22(5):821. doi: 10.3390/molecules22050821.
Bitter taste elicits an aversive reaction, and is believed to protect against consuming poisons. Bitter molecules are detected by the Tas2r family of G-protein-coupled receptors, with a species-dependent number of subtypes. Chickens demonstrate bitter taste sensitivity despite having only three bitter taste receptors-ggTas2r1, ggTas2r2 and ggTas2r7. This minimalistic bitter taste system in chickens was used to determine relationships between in-vitro (measured in heterologous systems) and in-vivo (behavioral) detection thresholds. ggTas2r-selective ligands, nicotine (ggTas2r1), caffeine (ggTas2r2), erythromycin and (+)-catechin (ggTas2r7), and the Tas2r-promiscuous ligand quinine (all three ggTas2rs) were studied. Ligands of the same receptor had different in-vivo:in-vitro ratios, and the ggTas2r-promiscuous ligand did not exhibit lower in-vivo:in-vitro ratios than ggTas2r-selective ligands. In-vivo thresholds were similar or up to two orders of magnitude higher than the in-vitro ones.
苦味会引发厌恶反应，人们认为它能防止摄入有毒物质。苦味分子由G蛋白偶联受体的Tas2r家族检测，其亚型数量因物种而异。尽管鸡只有三种苦味受体——ggTas2r1、ggTas2r2和ggTas2r7，但它们仍表现出苦味敏感性。鸡这种简约的苦味系统被用于确定体外（在异源系统中测量）和体内（行为学）检测阈值之间的关系。研究了ggTas2r选择性配体，尼古丁（ggTas2r1）、咖啡因（ggTas2r2）、红霉素和（+）-儿茶素（ggTas2r7），以及Tas2r混杂配体奎宁（对所有三种ggTas2r均起作用）。同一受体的配体具有不同的体内：体外比率，并且Tas2r混杂配体的体内：体外比率并不比ggTas2r选择性配体低。体内阈值与体外阈值相似，或比体外阈值高两个数量级。
