Fig. 6. Effects of F3 (A, C ) and F6 (B, D ) on whole-cell Na⁺current in isolated dorsal root ganglion neurons. (A, B ) Current traces in the presence and absence of F3 and F6, respectively. Representative peak current–voltage relations are shown for these currents, elicited by voltage steps from a holding potential of −120 mV to test potentials varying from −60 to +100 mV in two separate cells. Washout traces were recorded after 20 min perfusion with buffer containing no cyclobutane. (C, D ) Concentration–effect curves of pooled data for peak Na⁺current inhibition by F3 (C ; n = 11) or F6 (D ; n = 7), calculated as the percent inhibition of maximum inward current obtained from current–voltage plots from a holding potential of −100 mV. The maximal block of peak Na⁺currents by F3 was 70% at 0.6 mM (IC⁵⁰= 0.24 mM) and by F6 was 32% at 0.12 mM (IC⁵⁰= 0.02 mM).