Fig. 3. Drugs that modulate channels of the TASK subfamily of K_2P channels and different binding sites identified. (a) Chemical formula of the most important inhibitors of channels of the TASK subfamily. (b) Binding site of A1899 in a TASK-1 homology model [70, 71]. (c) Binding site of A293 in a TASK-1 homology model [72]. (d) Binding site of PK-THPP in a TASK-3 homology model [74]. (e) Illustration of the allosteric bupivacaine binding site in the side fenestration of a TASK-1 homology model [79]. (f) Binding site of BAY1000493 in TASK-1 determined by co-crystallization (PDB ID: 6RV3) [7]. (g) Chemical formula of the most important activators of channels of the TASK subfamily. (b-f) Potassium ions are represented by black spheres. Red arrows indicate the positions of the respective drugs in top view. *: homology model.