Has anyone ever measured resting potentials in primary neurons grown in Neurobasal-based cell culture media and compared to neurons grown in DMEM?

I grow E18 rat dissociated hippocampal cultures and find that neurons in DMEM-based media are much more exciteable and have much higher levels of spontaneous activity than when grown in neurobasal. Anyone else had a similar experience?

I noticed in the recipes, that the Na+ concentration in neurobasal is only about 58 mMol, versus about 120 for DMEM. Shouldn't make too much difference in resting potential, but maybe just enough. Also, maybe development if effected by abnormally low concentrations, like those that are found in neurobasal?

If you are talking about resting potential, how about the difference of K+ in these two media?Is K+ more important than Na+ in forming the resting potential?

K+ is the same for both media. If we believe the textbooks, the K+ is much more important in determining resting potential because K+ permeability is order of magnitude higher than Na+ permeability.

But maybe development from embryonic state onwards makes the game more complicated with trafficking of whoknowswhat into/out of membranes to get the cell up and running.

Clearly the driving force for sodium into the cell during the AP upstroke is less in neurobasal, due to lower Na+ concentration. Somewhat to my surprise, carrying out the calculations, I find that the driving force is only reduced by about 15%, compared to DMEM based medium. My intuition had guessed it might be closer to a factor of 2, but that's not the case.

so much withcraft in this cell-culture game...