FR 139317 is primarily used in research settings as a selective endothelin ETA receptor antagonist. It is widely employed in pharmacological studies to investigate the role of endothelin-1 and its receptors in various physiological and pathological processes. Specifically, it helps researchers understand the mechanisms underlying cardiovascular diseases, such as hypertension, heart failure, and vasoconstriction. By blocking the ETA receptor, FR 139317 allows scientists to study the effects of endothelin-1 on blood vessel tone, blood pressure regulation, and tissue remodeling. This compound is also used in experimental models to explore its potential therapeutic applications in conditions where endothelin signaling is dysregulated. Its selectivity for the ETA receptor makes it a valuable tool for distinguishing the contributions of ETA versus ETB receptors in endothelin-mediated responses.