What potential and/or current corrections should be applied to perforated patch recording?
What about liquid junction potential?
In short - the same currents/potentials as to whole cell patch-clamp recordings.
From an electrical point of view the perforated patch configuration is essentially similar to whole-cell, but with a slightly higher access resistance, as the membrane patch is not ruptured but merely perforated. So, you obtain a giga-seal and immediately clamp at -70 mV (or so), while you monitor the perforation process by test pulses (e.g. -5mV, as when you are opening the membrane in whole-cell recordings). You will also have the contribution of the liquid junction potential, which you can correct for if you wish.
Biochemically, it is different from the whole-cell config, as there is (almost) no mixing of the pipette solution with the cytosol and therefore no washout of the cell.
Good luck with it!
Mm... It is not that simple. In whole-cell mode there is no LJ potential between pipette solution and cytoplasm whatsoever, because they are completely mixed. Now imagine a perforated patch with let say K Gluconate in a pipette. Na diffuses freely through the perforated membrane, while for gluconate is remains impermeable, therefore junction potential forms with a cell positive compared to a pipette. However, this value is not so easy to measure or even to estimate. Maybe, best way is to make a solution where monovalent cations are in equilibrium with a cytoplasm, such that no diffusion is expected. Than no LJ is formed at this barrier.
Ups. Not "Na diffuses freely..." but "K diffuses freely" of course.
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