WIN 64338 hydrochloride is primarily used in research settings to study the role of bradykinin receptors in various physiological processes. It acts as a selective antagonist for the bradykinin B2 receptor, making it a valuable tool for investigating the mechanisms of inflammation, pain, and vascular regulation. Researchers utilize it to understand the pathways involved in conditions like hypertension, asthma, and chronic pain, as well as to explore potential therapeutic targets. Its application in experimental models helps elucidate the complex interactions of bradykinin signaling in disease states.