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. 2001 Dec 15;21(24):9585–9597. doi: 10.1523/JNEUROSCI.21-24-09585.2001

Fig. 5.

Fig. 5.

Extracellular field potential recordings of the effects of IbTX on the presynaptic compound action potential (fiber volley) and fEPSPs in CA1 stratum radiatum. A, Fiber volley and fEPSP in response to stimulation of presynaptic fibers in stratum radiatum. The glutamate receptor blockers DNQX (20 μm) and dl-AP5 (100 μm) blocked the fEPSP, thus isolating the fiber volley (FV). Application of 100 μm 4-AP broadened the fiber volley. B, Fiber volley recorded after DNQX, dl-AP5, and 4-AP (40 μm) application, as in A. Note the expanded time scale. Application of 100 nm IbTX broadened the volley further.C, Time course of the effect of IbTX on the fiber volley in the presence of DNQX, dl-AP5, and 4-AP (40 μm) (n = 5). The FV 90–10% decay time is plotted. D, Summary of the effect of IbTX on the fiber volley. As in C, the 90–10% decay time is plotted (mean ± SEM; n = 5 slices), showing a highly significant difference (p = 0.0041;n = 5). E, The effect of 100 nm IbTX of the fEPSP, recorded in 100 μm 4-AP and 100 μmdl-AP5, but without DNQX.F–I, Time courses (F,H) and summary diagram (G,I) of the effect of IbTX on the fEPSP (F, G) and PPR (H,I) in the presence of 100 μm 4-AP, but no DNQX. Mean ± SEM for five slices. The effects of IbTX on both the EPSP amplitude (G) and the PPR (I) were significant (p = 0.046 and p = 0.0078, respectively; n = 5).