Substance P (1-4)

Substance P is an 11-amino acid polypeptide with the sequence{Arg}{Pro}{Lys}{Pro}{Gln}{Gln}{Phe}{Phe}{Gly}{Leu}{Met}-NH2. In the central nervous system, Substance P has been associated with the regulation of mood disorders, anxiety, stress, reinforcement, neurogenesis, respiratory rhythm, neurotoxicity, nausea/emesis,and pain.Subtance P also works as a potent vasodilator. These effects are caused by the release of nitric oxide from the endothelium. This release can cause hypotension. Substance P is involved in the transmission of pain impulses from peripheral receptors to the central nervous system. It has been theorized that it plays a part in fibromyalgia. Capsaicin has been shown to reduce the levels of Substance P, probably by reducing the number of C-fiber nerves or rendering these nerves more tolerant.