Tachykinins are a family of neuropeptides that play important roles in the nervous system and various physiological processes. They are involved in functions such as pain perception, inflammation, and the regulation of mood. The most well-known tachykinin is substance P, which is primarily associated with transmitting pain signals. These peptides act by binding to specific receptors, known as tachykinin receptors, which are found throughout the body, including the brain and gastrointestinal tract. Tachykinins are also implicated in various conditions, such as asthma and depression, making them a focus of research for potential therapeutic applications.