麻痹性贝毒(paralytic shellfish poisoning, PSP)是分布最广、 危害最大的赤潮毒素, 可阻断钠离子通道从而抑制动作电位的形成导致动物体中毒。 以膀胱癌移行细胞T24为实验材料, 采用电压敏感荧光染料bis-oxonol, 根据PSP毒素GTX2,3对藜芦定诱导细胞去极化的抑制作用, 建立了一种麻痹性贝毒电压敏感荧光染料检测法。 实验结果显示, 在2～100 ng·mL-1范围内, PSP毒素GTX2,3可显著改变培养体系的荧光强度, GTX浓度与荧光强度之间存在很好的线性关系。 市售贝类PSP毒素检测结果表明, 此方法测定结果与小鼠法基本一致, 但灵敏度更高, 说明根据GTX浓度与荧光强度之间的线性关系可实现对样品中PSP毒素的快速检测。 利用电压敏感荧光染料测定贝体中的麻痹性贝毒是一种非常有潜力的贝毒快速筛查方法。

We developed a method to screen paralytic shellfish poisoning (PSP) toxins based on their functional activity. The assay was a fluorimetric assay by detecting changes in the membrane potential of transitional cell carcinoma of the bladder cells T24 and involved several steps: stain of T24 cells with fluorescent dye bis-oxonol, cell depolarization with veratridine, and inhibition of depolarization with PSP toxins GTX2,3 or shellfish samples containing PSP toxins. Toxic potency of the samples was evaluated by measuring toxin-induced changes in membrane potential. Within 2-100 nmol·L-1 of GTX2,3, veratridine-induced depolarization was shown to be inhibited by GTX2,3 in a dose-dependent manner. There was a linear correlation between the percentage of inhibition and toxin concentration. The PSP toxin value in shellfish obtained by this fluorescence assay was in concordance with that by the mouse bioassay, and with higher sensitivity. In conclusion, the fluorescent dye method based on changes in membrane potential was a rapid, specific, and reliable method for detecting paralytic shellfish poisoning toxins in shellfish.