Fig. 7. Role of the C-terminal 42 amino acids (C42) of the sulfonylurea receptor (SUR) in adenosine triphosphate–sensitive K⁺channel inhibition by local anesthetics. (  A ) Schematic diagram of wild-type and chimeric SURs. Chimera sulfonylurea receptor 2-1 (SUR2-1); SUR2 with the SUR1 C42, chimera sulfonylurea receptor 1-2A (SUR1-2A); SUR1 with SUR2A C42, and chimera sulfonylurea receptor 1-2B (SUR1-2B); SUR1 with SUR2B C42. COOH and NH²indicate the C and N termini of SUR, respectively. (  B ) Effects of bupivacaine (1 mm), levobupivacaine (1 mm), and ropivacaine (1 mm) on single-channel currents of the recombinant truncated isoform of inwardly rectifying K⁺channel 6.2 (Kir6.2ΔC36), and Kir6.2 channels with SUR2A, SUR2B, SUR1, SUR2-1, SUR1-2A, or SUR1-2B channels. The  dashed line indicates the level of inhibition observed for wild-type Kir6.2ΔC36 channels. Each  horizontal bar constitutes measurements from 8–11 patches (mean ± SD). *  P < 0.05  versus wild-type Kir6.2ΔC36 channels.