Hi everyone,
I have a few questions regarding the cell-attached patch clamp and BKca channel -
1) What I know is cell-attached patch clamp is reversed, that means the holding potential and current tracing is also reversed? So should i reverse the holding potential potential and current tracing being reported in research papers?
For example, If a paper says that the BKca channel opening was inward at say -40mv in cell-attached voltage clamp mode, does that mean the real holding potential was 40mv and the channels actually opened outwards?
2) I know that when BKca channels open due to increased calcium or voltage, they let potassium out of the cell. Does that mean the current should be outward? Because when I use the cell-attached voltage clamp, the currents have been inward of this channel. Please note that our solutions contain 145mM potassium, are sodium free and the bath solutions has only 0.06microM of calcium.
Thank a bunch for taking the time to read my question. Any suggestion will be appreciated.
Dear Sayeman:
It would be better to reverse the holding potential and current tracing as you are prepared to write the manuscript. Notably, BK(Ca) channels exhibits strong outward rectification. In cells bathed in high-K+ solution, as the holding potential was set at +50 mV, the current tracing should be directed outward and the upward deflection should indicate the opening event of the channel.
Hi Sayeman,
1.145 mM K bath makes K channel reversal potential 0 mV (membrane and reversal potential should be 0 mV as well). When you depolarize the cell (>0 mV), you should get outward current, and when you hyperpolarize the cell (
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