Used primarily in neuroscience research to study opioid receptors, particularly the mu-opioid receptor subtype. It acts as a selective agonist, helping scientists understand pain modulation, addiction mechanisms, and neurotransmitter release in the central nervous system. Commonly applied in in vitro and in vivo experiments to evaluate analgesic effects and receptor signaling pathways. Due to its high selectivity, it is valuable for distinguishing mu-receptor activity from delta or kappa opioid receptor effects. Often administered in controlled laboratory settings via injection or perfusion in animal models.