Used primarily in scientific research to study opioid receptors, particularly the delta-opioid receptor subtype. It acts as a selective antagonist, helping researchers understand receptor function and signaling pathways. Commonly applied in neuropharmacology studies to investigate pain modulation, addiction mechanisms, and the effects of other opioid drugs. Also utilized in behavioral experiments in animal models to explore the role of delta receptors in mood, anxiety, and drug-seeking behavior. Not used clinically and intended for laboratory use only.