BQ-788 is primarily used in research settings as a selective endothelin B (ETB) receptor antagonist. It is widely employed in studies to investigate the role of ETB receptors in various physiological and pathological processes, such as vascular regulation, blood pressure modulation, and kidney function. Researchers use BQ-788 to block ETB receptor activity, helping to understand its involvement in diseases like pulmonary hypertension, heart failure, and chronic kidney disease. Additionally, it is utilized in pharmacological experiments to differentiate the effects of ETB receptors from endothelin A (ETA) receptors, providing insights into the complex signaling pathways of the endothelin system.