Description_x000D_ Amino Acid Sequence_x000D_ Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2_x000D_ General description_x000D_ Substance P is a small peptide produced by macrophages, lymphocytes, eosinophils, dendritic cells and nerves. It is part of the neurokinin group._x000D_ Application_x000D_ Substance P acetate salt hydrate has been used in competition binding assays._x000D_ Substance P acetate salt hydrate has been:_x000D_ • used as a neurokinin 1 (NK1) receptor agonist for the activation of spinal nociceptive circuitry in mice_x000D_ • administered in central nucleus (ACE) in rat to study its positive reinforcing effects_x000D_ • used as an inhibitor of myosin light chain kinase in isolated lymphatic vessels from rat_x000D_ Biochem/physiol Actions_x000D_ NK-1 agonist; potent vasodilator and hypotensive agent; induces salivation; increases capillary permeability; induces mast cell degranulation; putative neurotransmitter in sensory (pain) afferents._x000D_ Substance P has proinflammatory effects on epithelial and immune cells. It has been associated with inflammatory diseases related to gastrointestinal and respiratory systems. Substance P modulates contractility of smooth muscles, transport of ions in the epithelium, vascular permeability and immune functions in the gut.