So I'm using whole-cell voltage clamp to record from a cell that has
two classes of inhibitory inputs. One to the soma, and one (largely)
to the dendrites, which I can activate independently. I/V plots show
me that the apparent reversal potential of the dendritic input is 10mV
lower than the somatic input. This could be due to the fact that a)
there is active Cl- homeostatis in the dendrites, which means that the
reversal potential truly is lower there, or b) I have poor space
clamp, and hence I have to drive the somatic voltage below the actual
reversal potential to get the potential at the dendrite to the
reversal potential. (or I suppose both). There is plenty of evidence
that I don't have proper voltage clamp of the dendritic events (slower
rise and decay time).
Is there any way to figure out whether this effect is solely due to
cable filtering of my command voltage?