T－2毒素对心肌细胞三型钙通道的阻滞作用

用膜片钳连细胞电压钳法, 在培养的Wistar大鼠单个心肌细胞上记录了T-2毒素对B、L和T三型Ca²⁺通道单通道电活动的影响. 结果表明, T-2毒素浓度为10mg/L时, 心肌细胞B、L和T三型Ca²⁺通道均受到明显的阻滞, 其阻滞作用表现为使Ca²⁺通道的开放概率减小, 开放时间缩短, 关闭时间延长, 而对流过Ca²⁺通道的Ba²⁺流幅值无影响.

Single Channel Analysis on the Calcium Blockade Action of T-2 Toxin in the Cultured Cardiac Cells

The effects of T-2 toxin on the activities of B-type, L-type and T-type Ca²⁺ channels were recorded on cultured ventricular myocardiocytes of neonatal Wistar rats by cell-attached patch clamp technique. T-2 toxin at dose of 10 mg/L significantly inhibited the activities of the three types of Ca²⁺ channels. The open time of Ca²⁺ channels was shortened and the openstate probability was decreased, whereas there were no significant variations in the amplitude of ionic current flowing through the Ca²⁺ channels. Compared with verapamil and Bay K 8644, the effects of T-2 toxin on the Ca²⁺ channels were similar to the blockade effect of verapamil. It was suggested that the cytotoxic action of T-2 toxin may be due to the damages of cell membrane .