Figure 2.

Differential block of EPSCs by γ-DGG. A, The cumulative amplitude distribution of EPSCs allows the selection of events in the smallest decile (E_10%) and those in the largest decile (E_90%). The blue trace shows that 2 mm γ-DGG, a low-affinity AMPA receptor antagonist, reduces the amplitudes of both small and large events. B, After averaging 10–20 events each from the E_90% and E_10% classes, events within ±2 pA, under control circumstances (black) or in the presence of 2 mm γ-DGG (blue), the result for the E_90% class in γ-DGG is normalized to that in control solution (green). When the same normalization factor is applied to the E_10% results, that for γ-DGG (green) is substantially smaller than that in control solution (black), indicating that γ-DGG blocks smaller EPSCs more efficaciously. C, In a comparison of EPSCs in control solution (black) with those in 100 nm NBQX (red), normalization shows that events in the E_90% and E_10% classes are blocked to a similar extent (green). D, When the ratios (E_10%/E_90%) for results in γ-DGG (blue) and NBQX (red) are normalized to their corresponding controls, the normalized ratio is significantly reduced by γ-DGG (6 cells) but not by NBQX (5 cells). Statistical significance was evaluated with a paired Student's t test.