PD-123319 is primarily used as a selective antagonist for the angiotensin II type 2 (AT2) receptor, making it a valuable tool in cardiovascular and renal research. It helps scientists differentiate the effects of AT2 receptor activation from those mediated by the AT1 receptor in physiological and pathological processes. It is commonly applied in studies investigating blood pressure regulation, vascular function, and tissue remodeling. Researchers also use PD-123319 to explore the role of AT2 receptors in conditions such as hypertension, heart failure, and kidney disease. Additionally, it has been utilized in neuroscience to examine the involvement of the renin-angiotensin system in neuroprotection and neuronal signaling. Its specificity allows for targeted inhibition, supporting mechanistic studies in both in vitro and in vivo models.