New development of transduction mechanism in chemical senses

对嗅觉和味觉受体机制的研究取得了不同的结果：(1)嗅觉细胞存在不依赖于cAMP和IP3的转导通路。这一途径不依赖于Ca、NO和cGMP。此外，还发现甲鱼嗅觉细胞膜流动性的改变影响嗅觉细胞对气味的辨别能力，提示嗅觉细胞膜的脂质层参与了气味的接受。(2)小鼠味觉细胞给予低浓度糖精可提高cAMP水平，高浓度糖精可提高IP3水平。果蝇味觉细胞的糖反应被抑制产生IP3的抑制剂所抑制，提示IP3参与了果蝇味觉细胞对糖的接受。研究还发现，酸性磷脂如磷脂酸、磷脂酰肌醇和磷脂酰丝氨酸可抑制各种物质的苦味。在这些脂质中，磷脂酸对苦味的抑制效果最好。

Various results on olfactory and gustatory receptor mechanisms were obtained.(1) It was found that there is a transduction pathway independent of cAMP and IP3 in olfactory cell. This pathway was independent of Ca, NO and cGMP.It was also found that membrane fluidity changes of turtle olfactory cell affect ability to discriminate odorants, suggesting that lipid layr of olfactory cell membranes in involved in oder reception.(2) It was found that application of low concentration of saccharine to mouse taste cells increased cAMP level and that of high concentration of saccharine increased IP3. The suger response in fly taste cell was suppressed by inhibitors for production of IP3, suggesting that IP3 is involved in sugar reception in fly taste cell. It was also found that bitterness of various substances is suppressed by acidic phospholipids such as phosphatidic acid, phosphatidylinositol and phosphatidylserine. Among these lipids, phosphatidic acid was most effective to suppress bitterness.