I tried to patch HEK cells (no transfected). My contidion is:
at room temerature
(K)i = 140 mM
(K)o = 4 mM
EK = -90 mV
At holding potential (-80 mV), most of times an inward holding current around -30 and -70 pA which seems to be reasonable (holding potential (-80 mV) > K reversal potential (-90 mV)).
But in some cells, I got an outward current around +20 pA.
How to interpret this outward current?