I'm patching Cav2.2 channel expressed in tsA201 cells.
I have problems in current size and success rate.
Usually I get only one suitable current size (>0.5nA) in 10 whole cells. Also most of the cells have current near 100pA.
I already checked concentration, 260/280 and 260/230 ratio and they are in adequate range.
However, one of my colleague who also studies calcium channels, examined my cDNAs (alpha1 and others) and he concluded that my cDNA is somewhat wrong!!
I use miniprep for preparing cDNAs, but someone says that cDNAs for transfection might be prepared by midi or maxi prep due to higher endotoxin level. So I guess that it can be the source of problem.
So, do you use miniprep for prep cDNAs? And.. can higher endotoxin level cause small current?