G-protein-coupled receptors (GPCRs) play a crucial role in cellular signaling pathways. GPR antagonists are pharmacological compounds designed to block or inhibit specific GPCRs' activity, thereby modulating their downstream signaling. By interfering with GPCR function, these antagonists have the potential to treat various conditions, including hypertension, cancer, and neurodegenerative diseases. Understanding the mechanisms behind GPR antagonists can pave the way for innovative drug development and therapeutic interventions.