Increasing effects of S-methyl-l-cysteine on the extracellular d-serine concentrations in the rat medial frontal cortex

In an in vivo dialysis experiment, the intra-medial frontal cortex infusion of a system A and Asc-1 transporter inhibitor, S -methyl- l -cysteine, caused a concentration-dependent increase in the dialysate contents of an endogenous coagonist for the N -methyl- d -aspartate (NMDA) type glutamate receptor, d -serine, in the cortical portion. These results suggest that these neutral amino acid transporters could control the extracellular d -serine signaling in the brain and be a target for the development of a novel threapy for neuropsychiatric disorders with an NMDA receptor dysfunction.