Analysis Note This certified reference material (CRM) is produced and certified in accordance with ISO/IEC 17025 and ISO Guide 34. This CRM is traceable to NIST SRM. Biochem/physiol Actions Inhibitory neurotransmitter in spinal cord, allosteric regulator of NMDA receptors. General description Certified content by quantitative NMR incl. uncertainty and expiry are given in the certificate.Download your certificate at: http://www.sigma-aldrich.com. Legal Information TraceCERT is a registered trademark of Sigma-Aldrich Co. LLC