NK1, or neurokinin-1, is a receptor in the body that primarily binds to the neuropeptide substance P. This receptor plays a crucial role in various physiological processes, including pain perception, inflammation, and stress responses. It is found in the central nervous system and peripheral tissues, influencing mood and anxiety levels. In medical research, NK1 antagonists are being studied for their potential therapeutic effects. These drugs may help treat conditions like depression, anxiety disorders, and nausea associated with chemotherapy. By blocking the action of substance P, NK1 antagonists aim to alleviate symptoms related to these conditions.