氯氰菊酯异构体对黑胸大蠊神经钠钾通道的调制作用

MODIFIED ACTION OF CYPERMETHRIN ENANTIOMERS ON AXONAL SODIUM AND POTASSIUM CHANNELS OF PERIPLANETA FULGINOSA (SERVILLE)

用电生理油间隙、单纤维、电压钳位技术研究了氯氰菊酯顺、反异构体对黑胸大蠊[Periplaneta fulginosa(serville)]中枢神经大轴突钠通道的调节抑制作用,并探讨了反式异构体与钾通道的作用关系。结果证明:1.2×10^(-3)mol/L顺式异构体作用于钠通道,先使其开放,然后抑制。2.出现钠尾电流,表明有更多数量的钠通道处于开放状态。3.5.4×10^(-4)mol/L反式异构体可阻滞迟缓钾通道并降低钾电流I_K的峰值。

The action of cypermethrin enantiomers were tested on isolated giant axons of the cockroach Periplaneta fulginosa (Serville) by using oil-gap, single-fiber and voltage-clamp recording technique. The insecticidal activity of cypermethrin has been shown primarily related to the stercochemical features of the molecule. The results of the present studies further included the following aspects: 1. In voltage-clamp, the cis-cypermethrin (2×10-5 mol/L) did not modify potassium currents, but slowly reduced the peak inward current. 2. Prolonged sodium tail-current developed after 20-25 minutes of cypermethrin exposure, presumably due to that fact that more sodium channels were held in the open state for an extended period. 3. The sup-prtssion of both sodium and potassium currents by the trans-cypermethrin (5.4×10-4mol/L) was noted after 75-90 minutes of exposure.