Paired-pulse depression can be rescued in PV−/− mice by EGTA.
(A) Superimposed IPSCs recorded in a Purkinje cell
(dotted traces, post) of a PV−/− mouse after induction of two
action potentials in a presynaptic interneuron by depolarizing steps
(30 ms ISI) and average response for the entire experiment (solid
trace). The interneuron was recorded with a solution containing 50 μM
EGTA. (B) Representative results from a similar
experiment where the interneuron was recorded with a solution
containing 1 mM EGTA. (C) Average PPR as a function of
ISI in PV−/− mice in conditions where interneurons were
extracellularly stimulated (open diamonds, same data as in Fig.
2C), or were recorded with a solution containing 50 μM
EGTA (filled squares, n = 13), or were recorded
with a solution containing 1 mM EGTA (filled diamonds,
n = 11).