Pharmacophore model of etomidate analogs with the merged surface of the five compounds having the highest γ-aminobutyric acid type A (GABA_A) receptor potencies. The surface colors are based on lipophilic potential ranging from brown (highly lipophilic) to blue (highly hydrophilic), and z-clipping was applied to the surface to match the GABA_A receptor comparative molecular field analysis contour maps. The dotted lines show interactions where a pharmacophore point on the ligand could be associated with one on the receptor-binding site because the volume constraint of the latter also fell within the 1-Å limit.