Neurokinin-1 (NK1) is a receptor in the body that primarily binds to a neuropeptide called substance P. This receptor is involved in various physiological processes, including pain perception, stress response, and inflammation. It plays a significant role in the central nervous system and is found in various tissues throughout the body. Research on Neurokinin-1 has led to the development of NK1 receptor antagonists, which are drugs designed to block its action. These antagonists are being studied for their potential to treat conditions such as depression, anxiety, and nausea, particularly in patients undergoing chemotherapy.