We also tested the effects of two chemically unrelated NMDA receptor antagonists, the anti-convulsant MK-801 (dizocilpine) [32, 33] , a non-competitive inhibitor of NMDA receptors, and APV (D-2-amino-5-phosphonovalerate), a competitive NMDA receptor antagonist [34, 35] , as well as the NMDA substrate itself, on macrophage TNF secretion in response to antibiotic-treated CA-MRSA bacteria.