Animal behavioral studies on the candidate of fat receptor protein

本研究发现，GPR120体外结合试验获得的饲料脂肪酸结合特异性曲线与舔体法评价的脂肪酸适口性曲线相吻合。从小鼠舌轮廓乳头味蕾分离细胞的钙成像试验中观察到相同的脂肪酸特异性谱。这些发现支持了我们的假设，即GPR120是舌头上长链脂肪酸的化学受体之一。在动物行为学实验中，小鼠对供试品中0.25%的低浓度长链多不饱和脂肪酸具有较高的适口性。特别是，小鼠摄入了油酸，这是一种流行的膳食脂肪酸，即使它是0.125%的低浓度，这表明在食物中添加极少量的膳食脂肪酸增加了食物的适口性。我们建立了GPR120基因敲除小鼠。小鼠对脂肪的适口性没有降低。这些结果表明，食物中所含的脂肪酸可能是通过GPR120和其他机制（包括CD36和未知的脂肪酸受体）协同接受的。

In this project, we found that the profiles of binding specificities for dietary fatty acidsobtained from GPR120 binding test in vitro coincided with the profiles of palatability ofmice to the fatty acids evaluated by lick examination. The same profiles of the specificityof fatty acids was observed from the calcium-imaging test using isolated cells from micetaste buds in the circumvallate papilla in the tongue. These findings supported ourhypothesis that GPR120 is functioning as one of the chemical receptors of long chain fattyacid on a tongue. In the animal behavioral experiments, mice have recognized 0.25% oflow-concentration long-chain poly-unsaturated fatty acid in the test sample with highpalatability. Especially, mice took oleic acid, one of the popular dietary fatty acids, evenit was 0.125% of low-concentration, suggesting that addition of very small quantity ofdietary fatty acid to the food increases in the palatability of foods. We created GPR120knockout mice. The mice did not show the diminish of palatability of fat. These resultssuggest that fatty acid contained in food may be received by in cooperation with GPR120and another mechanisms including CD36 and unknown fatty acid receptors.