Catalytically inactive PLD1 inhibits neurotransmission by decreasing
the number of functional presynaptic release sites. (A)
Variance to mean amplitude of IPSC ratio (V/Iav)
determined 120 min after PLD1(K898R) injection and normalized to value
before injection. (B) Using a binomial model for
release, consequences on V =
f(Iav) were simulated when
IPSC amplitude was decreased after p, n,
or q reduction. Note the typical graphical signature for
each quantal parameter change. (C1)
Representative experiment in which IPSC amplitude was reduced by
decreasing the external [Ca2+/Mg2+] from
2.1 to low 0.14 (opens symbols). Then, after returning to high
[Ca2+/Mg2+], PLD1(K898R) was injected
(closed symbols). The solid lines corresponds to the ensemble
Iav of the data.
(C2) IPSC fluctuations (ΔI)
around their mean are calculated by subtracting
Iav to each IPSC amplitude value.
(D) The corresponding V =
f(Iav) plots.
(E) Normalized cumulative plots of five similar
experiments. Note that V data were illustrated by
stepping five data.