Pharmacological studies on toxins from marine organism

海洋生物毒素的药理研究

• 批准号: 05454567
• 负责人: OHIZUMI Yasushi
• 金额: $ 4.99万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05454567/
• 关键词: Ca; Channel; Marine toxine; Platelet; Astrocytoma; Maitotoxin; Zooxanthellatoxin-A; Eudistomin; チャネル; トキシン; ズ-ザンテラトキシンA; ホスホリパーゼA_2; トロンボキサンA_2; MAPキナーゼ; メチルベッド; ズ-サンテラトキシンA; ホスホリパーゼC; 血管平滑筋; Na; K-ATPase

Maitotoxin (MTX) is a water-soluble toxin isolated from the dinoflagellate Gambierdiscus toxicus. We reported for the first time that MTX activates voltage-independent Ca^<2+> channels on the cardiac plasma membrane. MTX caused aggregation of rabbit washed platelets. The cytosolic Ca^<2+> concentration ([Ca^<2+>] i) was also increased by the presence of MTX.The MTX-induced platelet aggregation and [Ca^<2+>] i-increase were totally abolished in a Ca^<2+>-free solution. These results suggest that the MTX-induced platelet activation is caused by an enhanced Ca^<2+>-influx presumably through voltage-independent Ca^<2+> channels.Zooxanthellatoxin-A (ZT-A) was isolated from a symbiotic marine alga, and the structure of ZT-A was determined to be a 62-membered lactone. ZT-A caused aggregation in rabbit platlets, but did not cause platelet aggregation or infcrease [Ca^<2+>] i in a Ca^<2+>-free solution. Indomethacin and SQ-29548 inhibited platelet aggregation and the increase in [Ca^<2+>] i ind … More uced by ZT-A.These results suggest that ZT-A elicited Ca^<2+>-influx from platelet plasma membranes. The resulting increase in [Ca^<2+>] i subsequently stimulates the secondary release of TXA_2 from platelets.In platlets ZT-A caused concentration-dependent protein tyrosine phosphorylation of 42kDa in the presence of 1mM Ca^<2+>. The protein tyrosine phosphorylation was inhibited by genistein. The 42kDa protein was identified as p42^<mapk> by immunoprecipitation with an anti-mitogen-activated protein kinase (MAPK) antibody. ZT-A released thromboxame (TX) B_2 and stimulated the liberation of arachidonic acid. ZT-A-induced TXB_2 release was completely inhibited by indomethacin, while the MARK activation was partially inhibited by it. These results suggest that ZT-A may activate a protein tyrosine kinase in the presence of external Ca^<2+>. The activated protein tyrosin kinase subsequently activates MAPK.The activation of MAPK in turn causes the liberation of arachidonic acid via phospholipase A_2, resulting in the release of TXA_2 from platelets. The detailed pharmacological studies suggest that the phospolipase A_2 activation is relevant to a protein tyrosine kinase. Less

Maitotoxin （MTX）是一种水溶性毒素，是从钩鞭毛虫甘比铁饼毒中分离出来的。我们首次报道了MTX激活心脏质膜上电压无关的Ca^<2+>通道。甲氨蝶呤引起家兔洗涤血小板聚集。细胞内Ca^<2+>浓度（[Ca^<2+>] i）也因MTX的存在而升高。在不含Ca^<2+>的溶液中，mtx诱导的血小板聚集和[Ca^<2+>] i升高完全被消除。这些结果表明，mtx诱导的血小板活化是由Ca^<2+>-内流增强引起的，可能是通过电压无关的Ca^<2+>通道。从一种共生海藻中分离得到Zooxanthellatoxin-A (ZT-A)，确定其结构为62元内酯。ZT-A在兔血小板中引起聚集，但在不含Ca^<2+>的溶液中不引起血小板聚集或升高[Ca^<2+>] i。吲哚美辛和SQ-29548抑制血小板聚集和[Ca^<2+>]升高，ZT-A的作用更明显。这些结果表明ZT-A引起血小板质膜Ca^<2+>-内流。由此导致的[Ca^<2+>] i的增加随后刺激血小板中TXA_2的二次释放。在血小板中，ZT-A在1mM Ca^<2+>存在下引起42kDa的浓度依赖性蛋白酪氨酸磷酸化。染料木黄酮抑制蛋白酪氨酸磷酸化。42kDa蛋白通过抗丝裂原活化蛋白激酶（mapk）抗体免疫沉淀鉴定为p42^<mapk>。ZT-A释放血栓素（TX） B_2，促进花生四烯酸的释放。吲哚美辛完全抑制zt - a诱导的TXB_2释放，部分抑制MARK激活。这些结果表明ZT-A可能在外部Ca^<2+>存在的情况下激活蛋白酪氨酸激酶。被激活的酪氨酸激酶随后激活MAPK。MAPK的激活反过来通过磷脂酶A_2释放花生四烯酸，导致血小板释放TXA_2。详细的药理研究表明，磷脂酶A_2的活化与一种蛋白酪氨酸激酶有关。少

项目成果

Nakamura, H., et al.: "Structure of periodate oxidation products with characteristic partial structures of zooxanthellatoxin-A,a potent vasoconstrictive polyol from a symbiotic dinoflagellate." J.Org. Chem.58. 313-314 (1993)

Nakamura, H. 等人：“高碘酸盐氧化产物的结构，具有虫黄藻毒素-A 的特征部分结构，虫黄藻毒素-A 是一种来自共生甲藻的强效血管收缩多元醇。”

Takahashi, Y., et al.: "4,6-Dibromo-3-hydroxycarbazole (an analogue of caffeine-like Ca^<2+> releaser), a novel type of inhibitors of Ca^<2+>-induced Ca^<2+> release in skeletal muscle sarcoplasmic reticulum." Br. J.Pharmacol. 114. 941-948 (1995)

Takahashi, Y., et al.：“4,6-二溴-3-羟基咔唑（咖啡因样 Ca^<2> 释放剂的类似物），一种新型 Ca^<2> 诱导的 Ca^<

Takahashi,Y.et al.: "Structure-activity relationship of a powerful Ca^<2+> releaser,bromoeudistomin D" Eur.J.Pharmacol.Mol.Pharmacol.Sec.(in press).

Takahashi,Y.et al.：“强效Ca^2释放剂bromoeudistomin D的结构-活性关系”Eur.J.Pharmacol.Mol.Pharmacol.Sec.（正在印刷中）。

Masatoshi Adachi 安達正俊: "The specific binding site of 9-[3H]Methyl-7-bromoeudistomin D,a caffeine-like Ca2+ releaser,in liver microsomes in distinct from that in skeletal SR" Biological Chemistry Hoppe-Seyler. (in press). (1994)

Masatoshi Adachi Masatoshi Adachi：“9-[3H]甲基-7-bromoeudistomin D（一种咖啡因样 Ca2+ 释放剂）在肝微粒体中的特异性结合位点与骨骼 SR 中的结合位点不同”《生物化学 Hoppe-Seyler》（出版中） ）（1994）。

Nakamura, H.: "Isolation of zooxanthellatoxins, novel vasoconstrictive substances from the zooxanthella Symbiodinium sp" Toxicon. 31. 371-376 (1993)

Nakamura, H.：“从虫黄藻共生藻中分离出虫黄藻毒素，一种新型血管收缩物质”Toxicon。