Measurements were made in the absence (○) or presence (▪) of 100 µm MgADP. The conductance in the presence of meglitinide (G) is expressed as a fraction of its mean amplitude in the absence of both drug and nucleotide (Gc). The lines are the best fit of the mean data to eqn (1) using the following values: A, Kir6.2/SUR1; no nucleotide (n = 6): A = 1, IC50= 0.3 µm, nH= 1.0, L = 0.20. MgADP (n = 5–10): A = 1.64, IC50= 0.6 µm, nH= 1.0, L = 0.09. B, Kir6.2/SUR2A; no nucleotide (n = 5): A = 1, IC50= 0.6 µm, nH= 1.2, L = 0.25. MgADP (n = 6–8): A = 2.0, IC50= 1.7 µm, nH= 1.0, L = 0.70.