The initial objective of this study was to determine if activation of the sweet taste receptor TAS1R2/TAS1R3 is necessary for perception of sweet thermal taste (swTT). Our approach was to inhibit the receptor with the inverse agonist lactisole using a temperature-controlled flow gustometer. Because all prior studies of thermal taste (TT) used metal thermodes to heat the tongue tip, we first investigated whether it could be generated in heated water. Experiment 1 showed that sweetness could be evoked when deionized water was heated from 20 to 35 °C, and testing with static temperatures between 20 and 35 °C demonstrated the importance of heating from a cool temperature. As in previous studies, thermal sweetness was reported by only a subset of participants, and replicate measurements found variability in reports of sweetness across trials and between sessions. Experiment 2 then showed that exposure to 8 mM lactisole blocked perception of swTT. Confirmation of the involvement of TAS1R2/TAS1R3 led to an investigation of possible sensory and cognitive interactions between thermal and chemical sweetness. Using sucrose as a sweet stimulus and quinine as a nonsweet control, we found that dynamic heating capable of producing thermal sweetness did not increase the sweetness of sucrose compared with static heating at 35 °C. However, swTT was disrupted if trials containing sucrose (but not quinine) were interspersed among heating-only trials. These findings provide new information relevant to understanding the perceptual processes and receptor mechanisms of swTT, as well as the heat sensitivity of sweet taste in general.

中文翻译：

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甜热味：水中的感知特征和对 TAS1R2/TAS1R3 的依赖。

本研究的最初目的是确定甜味受体 TAS1R2/TAS1R3 的激活是否对于甜味热味 (swTT) 的感知是必要的。我们的方法是使用温控流量味觉计用反向激动剂乳糖醇抑制受体。因为之前所有的热味（TT）研究都使用金属热电极来加热舌尖，所以我们首先研究它是否可以在热水中产生。实验1表明，当去离子水从20°C加热到35°C时，会产生甜味，并且在20°C到35°C之间的静态温度下进行的测试证明了从低温加热的重要性。与之前的研究一样，只有一小部分参与者报告了热甜度，重复测量发现不同试验和不同疗程之间的甜度报告存在差异。实验 2 随后表明，暴露于 8 mM 乳糖醇会阻断 swTT 的感知。确认 TAS1R2/TAS1R3 的参与导致了对热甜味和化学甜味之间可能的感觉和认知相互作用的研究。使用蔗糖作为甜味刺激物和奎宁作为非甜味对照，我们发现与35℃静态加热相比，能够产生热甜味的动态加热并没有增加蔗糖的甜度。然而，如果含有蔗糖（但不含奎宁）的试验散布在仅加热的试验中，则 swTT 会受到干扰。这些发现提供了与理解 swTT 的感知过程和受体机制以及一般甜味的热敏感性相关的新信息。