MECHANISM OF MCH ACTION ON CHROMATOPHORES OF TELEOST FISH

MCH对最小鱼类色素细胞的作用机制

• 批准号: 04640674
• 负责人: OSHIMA Noriko
• 金额: $ 1.34万
• 依托单位: TOHO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04640674/
• 关键词: Melanin concentrating hormone (MCH); Melanophore; Teleost fish; MCH receptor; Cyclic AMP; Calcium ion; Protein kinase C; MCH fragments; 赤色素胞; サイクリックAMP; プロティンキナーゼC; 黒色素凝集ホルモン; カルシウム; 受容体; 白色素胞

The primary structure of melanin-concentrating hormone (MCH) purified from chum salmon pituitary was determined in 1983. In melanophores, MCH caused pigment aggregation in all teleosts studied, whereas pigment within erythrophores was not always aggregated. For example, swordtail erythrophores responded to MCH,but erythrophores present in tail fin of Nile tilapia did not at all. Moreover, the minimum effective does of MCH in swordtail erythrophores was rather higher than that in melanophores.Five analogues of MCH were tested for their melanin-aggregating activities in the in vitro fish skin (Corydoras paleatus) bioassay. Four analogues were fragments of the native sequence : Asp-Thr-Met-Arg-Cys-Met-Val-Cly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val with sequential elimination of substituents from both the carboxy- and amino- termini. Their relative effectiveness as follows : intact MCH > fragment (5-17) * fragment (1-15) > fragment (5-15) > fragment (1-14). Linear fragment (1-14) did not have the melanin-aggregating activity at all. From these results, we suggest the importance of S-S binding and the Trp^<15> residue for interaction with MCH receptors mediating melanosome aggregation. When intact MCH at concentrations higher than 1 muM was applied, the aggregation of melanosomes was followed by dispersion of them, suggesting that another type of MCH receptor mediating melanosome dispersion is also present on the melanophore membrane.Radio Immuno Assay indicated that the intracellular concentration of cAMP was decreased to about 55% of control value, when melanophores were treated with 10 nM MCH for 10 min, whereas intracellular level of cAMP was increased to about 126% when melanosomes were redispersed after the maximum aggregation by the treatment with 10 muM MCH.Moreover, it was shown in the present experiments, that Protein kinase C may be partly involved in the pigment aggregation, although calcium ions may not take part in the response.

黑素浓缩激素(MCH)的一级结构是1983年从鲑鱼脑垂体中分离纯化出来的。在黑素载体中，MCH导致所有被研究的硬骨鱼中的色素聚集，而红鱼体内的色素并不总是聚集的。例如，剑尾红鳍对MCH有反应，但尼罗罗非鱼尾鳍中的红鳍对MCH没有反应。此外，MCH在剑尾红细胞中的最小有效剂量远高于在黑素载体中的最小有效剂量。5个MCH类似物在体外鱼皮肤(Corydoras Pareatus)生物实验中测试了它们的黑色素聚集活性。有四个类似物是天然序列的片段：Asp-Thr-Met-Arg-Cys-Met-Val-Cly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val，从羧基和氨基末端顺序消除了取代基。其相对有效性为：完整的MCH&GT；片段(5-17)*片段(1-15)&GT；片段(5-15)&GT；片段(1-14)。线状片段(1-14)不具有聚集黑色素的活性。根据这些结果，我们认为S-S结合和Trp^&lt；15&gt；残基在与MCH受体相互作用介导黑素小体聚集中具有重要意义。用浓度大于1um的完整MCH处理黑素小体后，黑素小体聚集，随后黑素小体分散。放射免疫分析表明，10 nM MCH处理黑素细胞10min时，细胞内cAMP浓度降至对照的55%左右，而用10um微米MCH处理黑素小体达到最大聚集后，细胞内cAMP水平升高约126%。此外，本实验还表明，蛋白激酶C可能参与了色素聚集，尽管钙离子可能不参与这一反应。

项目成果

Nagaishi,H.and Oshima,N.: "Ultrastructure of the motile iridophores of the neon tetra." Zool.Sci.9. 65-75 (1992)

Nagaishi, H. 和 Oshima, N.：“霓虹灯四能动虹彩细胞的超微结构。”

Fujii,R.and Oshima,N.: "Factors influencing motile activities of fish chromatophores." In:Advances in Comparative and Environmental Physiology(Gilles,R.,ed.),Springer-Verlag,Berlin.20. 1-54 (1994)

Fujii,R. 和 Oshima,N.：“影响鱼类色素细胞运动活动的因素”。

Sugimoto, M.and Oshima, N.: "Changes in adrenergic innervation to chromatophores during prolonged background adaptation in the medaka, Oryzias latipes." Pigment Cell Res.(in press). (1995)

Sugimoto, M. 和 Oshima, N.：“在青鳉、Oryzias latipes 的长期背景适应过程中，肾上腺素能神经支配对色素细胞的变化。”

Hayashi,H.,Sugimoto,M.,Oshima,N.and Fujii,R.: "Circadian motile activity of erythophores in the red abdom nal skin of tetra fishes and its possible significance in chromatic adaptation." Pigment Cell Research. 6. 29-36 (1993)

Hayashi,H.、Sugimoto,M.、Oshima,N. 和 Fujii,R.：“四鱼红色腹部皮肤中红细胞的昼夜运动活动及其在色彩适应中的可能意义。”

Kitta.,K.,Makino,M.,Oshima,N.and Bern H.A.: "Effects of prolactins on the chromatophores of the tilapia,Oreochromin niloticus." Gen.Comp.Endocrinol.92. 355-365 (1993)

Kitta.，K.，Makino，M.，Oshima，N. 和 Bern H.A.：“催乳素对罗非鱼 Oreochromin 尼罗罗非鱼色素细胞的影响。”