It was recently suggested that applying high-frequency short biphasic pulses (HF-IRE) reduces pain and muscle contractions in electrochemotherapy and irreversible ablation treatments; however, higher amplitudes with HF-IRE pulses are required to achieve a similar effect as with monophasic pulses. HF-IRE pulses are in the range of a microseconds, thus, the so-called cancellation effect could be responsible for the need to apply pulses of higher amplitudes. In cancellation effect, the effect of first pulse is reduced by the second pulse of opposite polarity. We evaluated cancellation effect with high-frequency biphasic pulses on CHO-K1 in different electroporation buffers. We applied eight bursts of 1-10 µs long pulses with inter-phase delays of 0.5 µs - 10 ms and evaluated membrane permeability and cell survival. In permeability experiments, cancellation effect was not observed in low-conductivity buffer. Cancellation effect was, however, observed in treatments with high-frequency biphasic pulses looking at survival in all of the tested electroporation buffers. In general, cancellation effect depended on inter-phase delay as well as on pulse duration, i.e. longer pulses and longer interphase delay cause less pronounced cancellation effect. Cancellation effect could be partially explained by the assisted discharge and not by the hyperpolarization by the chloride channels.

中文翻译：

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在高频可逆和不可逆电穿孔中存在抵消作用。

最近有人提出，应用高频短双相脉冲（HF-IRE）可以减少电化学疗法和不可逆消融治疗中的疼痛和肌肉收缩。但是，为获得与单相脉冲相似的效果，需要使用HF-IRE脉冲的振幅更高。HF-IRE脉冲在微秒的范围内，因此，所谓的抵消效应可能是需要施加更高幅度的脉冲的原因。在抵消作用中，第一脉冲的作用被相反极性的第二脉冲减小。我们评估了高频双相脉冲在不同电穿孔缓冲液中对CHO-K1的抵消作用。我们施加了8个1-10 µs长的脉冲，相间延迟为0.5 µs-10 ms，并评估了膜的通透性和细胞存活率。在渗透率实验中 在低电导率缓冲液中未观察到消除作用。但是，在高频双相脉冲治疗中观察到了抵消作用，观察了所有测试电穿孔缓冲液的存活情况。通常，抵消效果取决于相间延迟以及脉冲持续时间，即较长的脉冲和较长的相间延迟会导致较不明显的抵消效果。抵消作用可以部分地通过辅助放电来解释，而不是通过氯离子通道的超极化来解释。较长的脉冲和较长的相间延迟会导致较不明显的抵消效果。抵消作用可以部分地通过辅助放电来解释，而不是通过氯离子通道的超极化来解释。较长的脉冲和较长的相间延迟会导致较不明显的抵消效果。抵消作用可以部分地通过辅助放电来解释，而不是通过氯离子通道的超极化来解释。