BU 226 hydrochloride is a selective ligand and antagonist for imidazoline I₂ receptors, commonly used in pharmacological research to investigate the role of these receptors in modulating monoamine oxidase (MAO) activity and other physiological processes. It aids in studies related to neurological and psychiatric disorders, such as depression, anxiety, Parkinson's disease, and addiction, by helping to elucidate I₂ receptor functions in the central nervous system. Valuable for in vitro and in vivo experiments to differentiate I₂ effects from other imidazoline receptor subtypes. Not intended for clinical or therapeutic use in humans.