Molecular transduction mechanisms in invertebrate tase receptor.

1.感受器电流的波动。其流过肉蝇的唇化学感觉毛的外腔。得出的结论是，这种波动反映了糖操纵的换能器离子通道的开闭动力学。从蔗糖和核糖之间动力学的差异以及刺激时受体电流的快速发展，推测该通道可能与糖受体分子形成复合物.采用膜片钳技术，对蛹羽化前2 - 3天的唇瓣进行酶处理，分离唇瓣味细胞。许多味觉细胞自发地诱发冲动。在离体外贴片上观察到蔗糖激活的单通道电流，证实了上述结论.对谷村博士分离的果蝇味觉接受突变体进行了分析。海藻糖位点突变体（X染色体）被推断为具有低亲和力海藻糖受体分子。一个新分离的吡喃糖位点突变体（第三染色体）被认为在受体膜上具有较少的吡喃糖位点受体分子.利用单克隆抗体和光亲和标记，从水螅中分离纯化了一种候选的谷胱甘肽受体分子R5。该分子的分子量为200 kDa，位于线虫细胞表面.肉蝇的标签盐受体细胞具有糖类似物、1，6脱水葡萄糖醇和二丁基-cGMP的受体位点，显示了该味觉细胞中广泛的受体形式。

1. Fluctuation of the receptor current. which flows through the outer lumen of the labellar chemosenosry hair of the fleshfly, was analyzed. The fluctuation was concluded to reflect the open-shut dynamics of sugar-operated transducer ion-channels. From the difference of dynamics between sucrose and rialtose and very rapid development of the receptor current upon stimulation, the transducer channel was suggested to be complexed with the sugar receptor molecule.2. We applied patch-clamp technique to the isolated labellar taste cells, prepared from the labellum of pupa 2 - 3 days before eclosion with enzymatic treatment. Many taste cells evoked impulses spontaneously. Sucrose activated single channel current was observed from the isolated out-side patch, confirming the above conclusion.3. Taste reception mutants of Drosophila nielanogaster isolated by Dr. Tanimura were analyzed. The Trehalose-site mutant (X-chromosome) was inferred to have low affinity trehalose receptor molecule. A newly isolated pyranose-site mutant (the third chropiosome) was suggested to have less pyranose-site receptor molecules on the receptor membrane.4. A candidate of glutathione receptor molecule, R5, was isolated and purified from Hydra Japonica, making use of monoclonal antibodies and photoaffinity labelling. This molecule had the molecular weight of 200 kDa and was located on the surface of nemotocytes.5. The labellar salt receptor cell of the fleshfly had receptor sites for sugar analogues, 1,6 anhydroglucitols and for dibutylyl-cGMP, showing wide range of recepton modality in this taste cell.