Complex sentence: ABT-418 is a drug which acts as a subtype-selective neural nicotinic acetylcholine receptor partial agonist, binding with high affinity to the α4β2, α2β2 and α7 subtypes, but not to the α3β4 subtype.
Split into simpler sentences: ABT-418 is a drug which acts as a partial agonist at neural nicotinic acetylcholine receptors. It binds with high affinity to the α4β2, α2β2 and α7 subtypes, but not to the α3β4 subtype.