Sp-cAMPS induces phosphatase-dependent LTD in the presence of
picrotoxin. (A) When slices were perfused with normal
ACSF (control, ●, n = 5), LTD
was induced after concurrent application of Sp-cAMPS (Sp) and
picrotoxin (PTX, 20–50 μM). After slices were pretreated with 1 μM
calyculin A (caly A) for 1 h, coapplication of Sp-cAMPS and
picrotoxin no longer induced LTD (○, n =
3). (B) This form of LTD is accompanied by an increase
in failure rate. (C) In the presence of anisomycin
(aniso, 20 μM), Sp-cAMPS and picrotoxin did not produce LTD
(n = 4). (D) Summary of data shown
in A and C. Picrotoxin (PTX) applied
alone did not cause significant depression (n = 4).
*, P < 0.01, compared with the PTX group.
Error bars indicate ± SEM.