This is my first posting & I hope some of you out there can help.
I would like to perform some studies of the NaV family using the voltage-sensitive dyes. Unfortunately I do not have easy access to a rig; I do have access to an FDSS (sim. to the TETRA).
I have seen several papers using these VS dyes to measure response w/ recombinant NaVs (293 or CHO) in the presence of veratridine with and without ATX2 & demonstrating response (Benjamin 2005, Felix 2004, posters at conferences (Astra Zeneca 2005, Ionix 2004)
1) Isn't the channel in an inactivated state, considering the RMP of the host cell is higher than the activation threshold (CHO=0- -10 & HEK= -20 - -40mV)?
2) To my knowledge veratridine binds to the open state, so I do not understand how veratridine can work if the channel is indeed inactivated. Can someone explain this?
3) Is it that these groups are using a stable, or one chosen w/ a lower RMP? Considering my results w/ ligand gated channels, etc. the expression levels should not be an issue.
4) Beta Subunits: Is it better or worse to express them w/ a flourometric readout?
I greatly appreciate your help, and hopefully can return the kindness in the future.