Figure 7.

CF-PC EPSCs and CF-BG responses are affected differentially by subtype-specific Ca²⁺ channel blockers. A, CF-PC EPSCs were recorded in 0.5 mm Ca²⁺ and 2.8 mm Mg²⁺ (Vh = -10 mV), and CF-BG responses were recorded in the same divalents with 200 μm CTZ (Vh = -65 mV) in the absence and presence of the P/Q-type Ca²⁺ channel blocker ω-agatoxin IVA (200 nm). B, Summary of the ratio of the response amplitudes in the presence and absence of ω-agatoxin IVA in A. CF-PC EPSC (n = 5); CF-BG response (n = 5). C, CF-PC EPSCs and CF-BG responses were recorded in the same conditions as in A in the absence and presence of the N-type Ca²⁺ channel blocker ω-conotoxin GVIA (1 μm). D, Summary of the ratio of the response amplitude in the presence and absence of ω-conotoxin GVIA in C. CF-PC EPSC (n = 4); CF-BG response (n = 4); unpaired t test, ^*p = 0.002. E, ω-Conotoxin GVIA (1 μm) partially blocked the CF-PC EPSC but mainly blocked the initial fast component of the CF-BG response, whereas the late slow component was blocked less (gray lines in BG recordings are double exponential fits). CF-PC EPSCs were recorded in 2 mm Ca²⁺, 1.3 mm Mg²⁺, and 2 mm γ-d-GG (Vh = -10 mV); CF-BG responses were recorded with the same divalents without γ-d-GG (Vh = -65 mV). F, Summary of the ratio of response amplitudes in the presence and absence of ω-conotoxin GVIA in E. CF-PC EPSC (n = 5); CF-BG response (n = 5); ANOVA and Fisher's PLSD post hoc test, significantly different for all combinations; ^*p < 0.004.