Role of F340 in determining anesthetic sensitivity. The inhibitory effects of isoflurane (0.5 mM) were determined in two KCNQ1 mutants, F340A and F340C, as shown in (A) and (B), respectively. The results are summarized in (C). Current inhibition was determined at a test-pulse potential of +60 mV from a −50 mV holding potential. Compared to the wild-type KCNQ1, the inhibition by isoflurane on the two mutants were significantly attenuated. However, between the two mutants, a significant difference was observed in the inhibition by isoflurane. *Significantly different from F340A, n = 4–5/group.