Studies on the types of the taste cell and taste perception.

关于味觉细胞到味觉细胞或味觉神经的通路还有许多悬而未决的问题。因此，我们利用行为学测试、钙离子成像和免疫细胞化学等方法对小鼠咖啡因的转导机制进行了分析。用钙离子显像法检测味觉细胞对咖啡因、三磷酸腺苷和高浓度钾的反应性，然后用免疫细胞化学方法检测G_α-Gustducin和IP_3R3的表达。结果，咖啡因刺激了味觉细胞II型和其他类型的细胞。部分II型细胞被高浓度K^去极化，并存在对咖啡因和高K^有反应的味觉细胞。因此，我们推断在II型细胞亚群中存在电压门控性钙通道。此外，三磷酸腺苷既能刺激II型细胞，也能刺激其他类型的细胞。考虑到有报道称，ATP是从II型细胞中释放出来的，它似乎在味觉细胞中发挥着自分泌作用。

There are a lot of unsolved issues about the pathway from taste cells to taste cells or taste nerves. Therefore, we analyzed the caffeine transduction mechanism of mouse using behavioral test, calcium imaging, and immunocytochemistry. The responsiveness of taste cells to caffeine, ATP, and high concentration of K^+ were examined by calcium imaging followed by immunocytochemistry to detect expression of G_α-gustducin and IP_3R3 which are known as type II cell markers. As a result, caffeine stimulated taste cells both type II and the other type of cells. A part of type II cells was depolarized by high concentration of K^+, and taste cells which responded to caffeine and high K^+ existed. Therefore we concluded there are voltage-gated calcium channels in subset of type II cells. Also, ATP stimulates both type II and other type of cells. Considering the report that ATP is released from type II cells, it seems to play an autocrine role in taste cells.