Fig. 10. 4-AP depresses the inhibitory actions of ENpa and GSPRFFamide on the nerve-evoked contraction. (A) Action of 10^–7 mol l^–1 ENpa on the contraction in the absence (Ai) or presence (Aii) of 10^–3 mol l^–1 4-AP. The contraction was evoked by the stimulus train (1 ms, 1.6 V, 10 Hz) for 0.4 s. (B) Inhibitory actions of 10^–7 mol l^–1 ENpa (Bi, N=5) and 10^–7 mol l^–1 GSPRFFamide (Bii, N=4) in the absence [(–)4-AP] or the presence [(+)4-AP] of 10^–3 mol l^–1 4-AP. Statistical significance was assessed by Student's t-test.