Deltorphin I is primarily used in research settings to study the function and regulation of delta opioid receptors. It is a highly selective agonist for these receptors, making it valuable for understanding pain pathways and opioid receptor signaling in the nervous system. Researchers utilize it to explore potential therapeutic applications, such as developing new pain management drugs with fewer side effects compared to traditional opioids. Additionally, it aids in investigating the role of delta receptors in mood regulation, addiction, and neurodegenerative diseases. Its specificity helps in distinguishing delta receptor activity from other opioid receptor types, contributing to advancements in pharmacology and neuroscience.