ON 146040 is primarily used in research and development within the field of pharmacology and biochemistry. It serves as a selective antagonist for the delta opioid receptor, making it a valuable tool in studying the role of these receptors in pain modulation, addiction, and neurological disorders. Researchers utilize this compound to explore its potential therapeutic effects, particularly in managing chronic pain and reducing opioid dependence. Additionally, it aids in understanding the signaling pathways and physiological responses associated with delta opioid receptors, contributing to the development of novel drugs targeting these pathways. Its application is limited to experimental and preclinical studies, focusing on advancing knowledge in neuroscience and drug discovery.