Outward Current in wild type CHO cells

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Bluejay's picture
Outward Current in wild type CHO cells

I am getting about a 0.5nA outward current in untransfected i.e. wild type CHO cells at 40mV. This makes it difficult to interpret the effects of inhibitors on cells transfected with known potassium channels, such as KvLQT1. Some literature suggests there are no functional potassium channels in wild type CHO and HEK cells although Frasermoss recently indicated some HEK cells have endogenous channels. Is there a way to get rid of this background? It is not inhibited by TEA or 4-AP, i.e. standard potassium channel inhibitors. Am using perforated whole cell voltage clamp on an IonworksHT, and regular HEPES-buffered internal and external solutions. Suggestions?

Fraser Moss
Fraser Moss's picture
The HEKs I have worked with

The HEKs I have worked with have always had endogenous K currents, but these are always blocked by TEA. And it is common practice to block them with low doses of TEA that don't effect whatever other channel you are studying.

The CHO-K1s I have used are great for hERG K recordings because they have no endogenous K currents. I use ATCC

CCL-61 CHO-K1 cells if you want to try those instead of the ones you are using. They just don't express hERG as well as the HEKs.