D-serine Measurements in Brain Slices or Other Tissue Explants.

D-serine is an atypical amino acid present in the mammalian body (most amino acids in the mammalian body are L-isomers) that is mostly known in neuroscience for its role as a co-agonist controlling the N-methyl D-aspartate receptor (NMDAR). D-serine levels are decreased in patients with schizophrenia and this is thought to mediate, at least in part, the hypofunction of NMDARs that is central to the glutamate hypothesis for the etiology of this neuropsychiatric disorder. D-serine detection was first established using high performance liquid chromatography, a costly and complex technique that requires high levels of expertise. But with the increasing interest in this unconventional amino acid, there is an increasing need for easier, cheaper and more accessible detection methods. Here we describe the amperometric, biosensor-based method we employed in a recent publication (Papouin et al., 2017b). It allows reliable measurement of D-serine levels from fresh tissue, such as acute brain slices, for concentrations higher than 100 nM, with minimal technical requirements.