Agmatine

Agmatine ((4-aminobutyl)guanidine, NH₂-CH₂-CH₂-CH₂-CH₂-NH-C(-NH₂)(=NH)) is the decarboxylation product of the amino acid arginine and is an intermediate in polyamine biosynthesis. It is discussed as a putative neurotransmitter. It is synthesized in the brain, stored in synaptic vesicles, accumulated by uptake, released by membrane depolarization, and inactivated by agmatinase. Agmatine binds to α₂-adrenergic receptor and imidazoline binding sites, and blocks NMDA receptors and other cation ligand-gated channels. Agmatine inhibits nitric oxide synthase (NOS), and it induces the release of some peptide hormones.