D-Cycloserine

D-cycloserine (DCS) is an antibiotic, inhibiting cell-wall biosynthesis in bacteria. It is a tuberculostatic agent, that inhibits L-alanine racemase and D-alanine:D-alanine ligase, enzymes essential to peptidoglycan synthesis and bacterial cell wall formation. Formulations containing DCS have been used as second-line agents to treat drug resistant tuberculosis. A reason for limited use of this drug is the neurological side effects it causes, since it is able to penetrate into the central nervous system (CNS). DCS acts as a glutamatergic partial N-methyl-D-aspartate (NMDA) agonist. It selectively binds at the glycine-binding site of the NMDA receptor and enable the opening of the NMDA channel. DCS has the ability to improve memory retention in senescence-accelerated mice which exhibit impaired learning and memory.