inward activating hERG current in CHO cells

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kunalshah67's picture
inward activating hERG current in CHO cells

Dear All,
Currently, I am recording hERG current in CHO cells by automated patch clamp setup. I apply voltage sweeps -90mv for 50 msec, -100mV  for 100 ms, -50 mv for 50 ms, 40 mV for 800msec, -50mV for 1200 msec , -120mv for 400msec, -90mV for 50 sec. The holding potential set to -90 mV. The seal resistance is less than 200- 300Mohm as it is automated setup, it cant be more than that.

The sweeps attached below is leak current compensated as well as baseline adjusted. Before baseline adjustment, the holding current (current at holding voltage -90mV) starts from positive value around 100-200 pA current.

Here, I got peak tail current, but the activating current is negative. so, what would be the possible reason for that ?

Are these effect is because of low seal resistance or there should be some changes require in voltage protocol ?

Are there any effect of leak current on activating hERG current ?