Neurokinin-1 receptors (NK1R) are a type of protein found on the surface of certain cells in the body. They are primarily activated by a substance called substance P, which is involved in transmitting pain and other sensory signals. NK1R plays a crucial role in various physiological processes, including pain perception, stress response, and inflammation. These receptors are distributed throughout the central and peripheral nervous systems, as well as in other tissues. Research on NK1R has implications for treating conditions like depression, anxiety, and chronic pain, as blocking these receptors may help alleviate symptoms associated with these disorders.