Substance P, also known as neurokinin-1, is a widely distributed 11-amino acid neuropeptide that preferentially activates the neurokinin-1 receptor (NK1R) and exerts excitatory effects on central and peripheral neurons and is involved in pain transmission. Substance P is also expressed by a variety of non-neuronal cell types such as microglia and immune cells and it stimulates mast cell degranulation and histamine release, proliferation and differentiation of lymphocytes, and induces immunoglobulin synthesis. Substance P dysregulation is associated with inflammatory diseases and obesity.
