I am just reading about cellular electrophysiological access to study
presynaptic or postsynaptic effect of different drugs and substances.
Apart of miniature EPSCs analysis, I found in the literature that some
people are applying two consecutive pulses (S1 and S2) at brief time
intervals to analyze the ratio of the second stimulation over the first
If this ratio is >1 they talk about paired-pulse facilitation (PPF), if
S2/S1<1 they call it paired-pulse inhibition (PPI)....
My question is... are those effects always presynaptic? if yes, why?
Thank you very much in advance.
Segundo JM Guzman