NPS-2143 hydrochloride is primarily used in research settings to study calcium-sensing receptors (CaSR). It acts as a selective antagonist of CaSR, making it valuable for investigating the role of these receptors in various physiological processes. Researchers utilize it to explore conditions related to calcium homeostasis, such as hyperparathyroidism and bone disorders. It also aids in understanding the mechanisms of CaSR in the regulation of parathyroid hormone secretion, which is critical in managing calcium levels in the body. Additionally, it is employed in studies targeting potential therapeutic interventions for diseases linked to CaSR dysfunction.