Contractile response of the rabbit aorta to maitotoxin, the most potent marine toxin.
Contractile response of the rabbit aorta to maitotoxin, the most potent marine toxin.
复制标题
兔子主动脉对麦毒毒素（最有效的海洋毒素）的收缩反应。
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
T. Yasumoto
中科院分区：
文献类型：
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作者：
Y. Ohizumi;T. Yasumoto
Maitotoxin （MTX）是最有效的海洋毒素，当浓度为10（‐10）‐3 × 10（‐8）g/ml时，可引起兔离体主动脉的剂量依赖性收缩。维拉帕米（10（‐6）M）对MTX的剂量收缩反应曲线平行向右移动，酚妥拉明（10（‐6）M）对MTX的剂量收缩反应曲线略微向右移动，而河豚毒素、甲塞吉特、氯苯那敏或吲哚美辛对MTX的剂量收缩反应曲线没有或几乎没有影响。在无Ca2+培养基中，MTX诱导的收缩被消除，并且随着Ca2+浓度在0.03至1.2 mM之间呈线性增加。在无Ca2+溶液中，通过重新引入Ca2+， Sr2+或Ba2+产生的收缩反应在MTX（10（‐8）g/ml.）和高浓度KCl （4 × 10（‐2）M）处理后增强。用维拉帕米（10（‐7）‐10（‐6）M）治疗后，在MTX或KCl存在下，Ca2+、Sr2+或Ba2+的剂量收缩反应曲线平行向右移动，表明竞争性拮抗作用。但在钙离子载体A23187 （3 × 10（‐5）M）存在的情况下，维拉帕米（10（‐6）M）对Ca2+的剂量响应曲线没有影响。MTX治疗后主动脉组织Ca含量增加31%（10（‐8）g/ml）。甲氨蝶呤的这种作用在维拉帕米的存在下被明显抑制。基于这些结果，我们认为MTX诱导的主动脉收缩主要是由对平滑肌的直接作用引起的，可能是由于Ca2+通透性的增加，这是通过平滑肌细胞膜上电压敏感的Ca2+通道发生的。
Maitotoxin (MTX), the most potent marine toxin, caused a dose‐dependent contraction of the rabbit isolated aorta at concentrations of 10(‐10)‐3 X 10(‐8) g/ml. The dose‐contractile response curve for MTX was shifted to the right in a parallel manner by verapamil (10(‐6) M), was slightly shifted to the right by phentolamine (10(‐6) M) and was not or little affected by tetrodotoxin, methysergide, chlorpheniramine or indomethacin. The MTX‐induced contraction was abolished by incubation in Ca2+‐free medium and was increased in a linear fashion with Ca2+ concentrations between 0.03 and 1.2 mM. In Ca2+‐free solution, the contractile responses produced by re‐introduction of Ca2+, Sr2+ or Ba2+ were potentiated after treatment with MTX (10(‐8) g/ml.) and a high concentration of KCl (4 X 10(‐2) M). After treatment with verapamil (10(‐7)‐10(‐6) M), the dose‐contractile response curve for Ca2+, Sr2+ or Ba2+ in the presence of MTX or KCl was shifted to the right in a parallel manner, indicating competitive antagonism. But the dose‐response curve for Ca2+ in the presence of A23187 (3 X 10(‐5) M), a Ca ionophore, was not affected at all by verapamil (10(‐6) M). The tissue Ca content of the aorta was increased 31% by treatment with MTX (10(‐8) g/ml.). This effect of MTX was markedly inhibited in the presence of verapamil. On the basis of these results, it is suggested that the MTX‐induced contraction of the aorta is caused mainly by a direct action on smooth muscle, possibly due to an increase in Ca2+ permeability which occurred through voltage‐sensitive Ca2+ channels in the smooth muscle cell membrane.