Recent evidence has shown that d-amino acids are present in animals and humans in high concentrations and fulfill specific biological functions. In the central nervous system, two d-amino acids, d-serine and d-aspartate, occur in considerable concentrations. https://www.ncbi.nlm.nih.gov/pubmed/15979028 Asked and answered Please Register or Log in to view the hidden image!
The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord https://en.m.wikipedia.org/wiki/Central_nervous_system Double answered Please Register or Log in to view the hidden image!