Comparative analysis of allyl isothiocyanate (AITC)-induced carbohydrate oxidation changes via TRPV1 between mice and chickens
Comparative analysis of allyl isothiocyanate (AITC)-induced carbohydrate oxidation changes via TRPV1 between mice and chickens
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DOI：
10.2220/biomedres.38.149
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发表时间：
2017-01-01
影响因子：
1.2
通讯作者：
Tabata, Shoji
中科院分区：
文献类型：
--
作者：
Kawabata, Fuminori;Kawabata, Yuko;Tabata, Shoji
餐后高血糖是心血管疾病的危险因素。据报道，胃内给予异硫氰酸烯丙酯（AITC），其是芥末和辣根的辛辣成分之一，但不包括在辣椒中，增加了碳水化合物氧化，并通过瞬时受体电位香草素1（TRPV 1）减少了小鼠餐后血糖的增加。然而，AITC对TRPV1增加碳水化合物氧化的作用位点尚不清楚。哺乳动物和鸡TRPV1（cTRPV1）都能被热和酸激活，但与哺乳动物不同的是，cTRPV1只能被辣椒素微弱激活。这种差异是由于跨膜3周围的8个鸡特异性氨基酸残基，这是大鼠TRPV1中辣椒素结合的主要位点。此外，AITC诱导的小鼠TRPV1（mTRPV1）的激活在很大程度上依赖于S513，这是一个参与辣椒素结合的残基。因此，我们推测，在哺乳动物中，AITC对碳水化合物氧化的增加是由AITC与TRPV1的辣椒素结合位点的结合诱导的。在这项研究中，我们使用鸡和小鼠进行了比较研究，因为鸡被认为部分缺乏TRPV1的辣椒素结合位点。我们研究了AITC对鸡和小鼠呼吸商（RQ），碳水化合物氧化和脂肪氧化指数的影响。呼吸气体分析显示AITC不增加鸡的RQ，Ca2+成像方法和全细胞膜片钳分析显示AITC不激活cTRPV1。这些结果表明辣椒素结合位点是AITC给药增加动物体内碳水化合物氧化的重要区域。
Postprandial hyperglycemia is a risk factor for cardiovascular diseases. It has been reported that intragastric administration of allyl isothiocyanate (AITC), which is one of the pungent ingredients of wasabi and horseradish but it is not included in hot chili pepper, increased carbohydrate oxidation and reduced postprandial increase of blood glucose via transient receptor potential vanilloid 1 (TRPV1) in mice. However, the action site of AITC on TRPV1 for increasing carbohydrate oxidation is unclear. Both mammalian and chicken TRPV1 (cTRPV1) are activated by heat and acid, but unlike its mammalian counterpart, cTRPV1 is only faintly activated by capsaicin. This difference is due to the 8 chicken-specific amino acid residues around transmembrane 3, which is the main site of capsaicin-binding in rat TRPV1. Moreover, AITC-induced activation of mouse TRPV1 (mTRPV1) is largely dependent on S513, a residue that is involved in capsaicin-binding. Thus, we hypothesized that the increase of carbohydrate oxidation by AITC in mammals is induced by the binding of AITC to the capsaicin-binding site of TRPV1. In this study, we performed a comparative study using chickens and mice, since chickens are thought to partly lack the capsaicin-binding site of TRPV1. We examined the effects of AITC on the respiratory quotient (RQ), the index of carbohydrate oxidation and fat oxidation, in chickens and mice. Respiratory gas analysis revealed that AITC does not increase the RQ in chickens, and Ca2+ imaging methods and a whole cell-patch clamp analysis showed that AITC does not activate cTRPV1. These results implied that the capsaicin-binding site is an important region for increasing carbohydrate oxidation by AITC administration in animals.