Bioactivity: NS3861 fumarate is an agonist of nicotinic acetylcholine receptors (nAChRs). NS3861 fumarate is a partial agonist at α3β4 nAChR and binds with high affinity to heteromeric α3β4 nAChR. The binding Ki values of 0.62, 25, 7.8, 55 nM for α3β4, α3β2, α4β4, α4β2, respectively[1].