Action of endothelins and related substances on the chromatophores of poikilothermal vertebrates

以青鳉为研究对象，研究了长时间背景适应后黑色素细胞对电刺激反应性的变化。发现在背景适应期间，色神经的兴奋性和神经支配的密度受到很大影响（Sugimoto等人，1994年）。然后，在两种鲶鱼上研究了介导黑色素细胞中色素聚集的毒蕈碱胆碱受体的药理学特征。这些受体与哺乳动物M_3型毒蕈碱胆碱受体相似（Hayashi和Fuji，1994）。对普通刺尾鱼（paracanthurus hepatus）皮肤的形态学观察表明，蓝色着色是由于存在类似于蓝色雀鲷的虹膜载体，但虹膜载体存在于双星中（Goda等人，1994年）。在两种丽鱼中发现了新的蓝色色素细胞。我们将它们命名为“蓝色素”，蓝色细胞器包含“蓝色素体”（Goda和Fujii，1995）。对介导鱼类黑色素细胞中色素聚集的内皮素受体进行了深入的药理学研究。结论是它们与哺乳动物ET_B型相似（Hayashi和Fujii，出版中）。我们在一篇综述文章中广泛讨论了影响鱼色素细胞运动的各种因素，包括内皮素和有关物质的影响（Fujii和Oshima，1994）。

Working on the medaka, Oryzias latipes, the changes in the responsiveness of melanophores to electrical nervous stimulation after prolonged background adaptation were investigated. It was found that the excitability of the chromatic nerves and the density of innervation were largely affected during the background adaptation (Sugimoto et al., 1994). Then, the pharmacological profiles of the muscarinic cholinoceptors that mediate aggregation of pigment in the melanophores were stidied on two species of catfish. It was indicated that thses receptors resembled those of mammalian muscarinic cholinpceptors of the M_3 type (Hayashi and Fuji, 1994). Morphological observations about the skin of the common surgeonfish, paracanthurus hepatus, showed that the blue coloration was due to the presence of iridophores resembling those of blue damselfish, but the iroidophores existed in double starta (Goda et al., 1994). Novel blue chromatophores were found in two species of callionymid fish. We named them the "cyanophores", and the blue organelles contained the "cyanosomes" (Goda and Fujii, 1995). Pharmacological studies on the endothelin receptors that mediate aggregation of pigment in fish melanophores were intensely studied. The conclusion was that they resembled those of the mammalian ET_B type (Hayashi and Fujii, in press). Including those of endothelins and of related substances, the effects of vaious factors influencing motile activities of fish chromatophores were widely discussed in a review article by us (Fujii and Oshima, 1994).