Hello everyone,
I am recording mEPSCs from CA1 hippocampal neurons in mice brain slices and I have been adding 1uM TTX and 100uM Picrotoxin to the external recording solution. As I read more published papers on this topic, it seems like some have TTX+GABAA inhibitor+CPP(a NMDA antagonist) in the external recording solution versus having only TTX and a GABAA antagonist.
Is it always necessary to add the CPP or can one record mEPSCs without NMDA receptor antagonists? Does the addition of CPP make the data cleaner or better (higher frequency) in anyway? Any advice from experts would be most useful.
I hold the neurons at -70mV during recording and use CsMeSO4 internal solution with QX-314.
Thanks
Dear Archan,
I assume you have (high) amounts of Mg2+ in your ACSF? If so, the chances of ion flow through NMDA receptors is minimal. However, as scientists we are in the business of being as sure as possible. So I would advise to include CPP or APV to block the NMDA receptors completely. It will also prevent a reviewer asking to redo your experiments when you are done and have submitted your work.
good luck
Nils
Thanks a lot Nils! You make a good point about the Mg2+ concentration. My recording solution has 2mM but I will add CPP and check the mEPSC frequency with the no CPP added recordings from the past.