ZD 7155 hydrochloride is primarily used in research settings as a selective antagonist for the angiotensin II type 1 (AT1) receptor. It is widely applied in studies focused on understanding the role of the renin-angiotensin system (RAS) in various physiological and pathological processes. Researchers utilize it to investigate cardiovascular functions, including blood pressure regulation, vascular tone, and cardiac remodeling. Additionally, it is employed in experimental models to explore its potential effects on kidney function, fluid balance, and electrolyte homeostasis. Its application extends to studying conditions such as hypertension, heart failure, and renal diseases, providing insights into the mechanisms of these disorders and aiding in the development of therapeutic strategies.