What is NMDA Antagonist Neurotoxicity and How do I Prevent It?
When NMDA antagonists were first studied they seemed like a dream come true: here were drugs which could block from part to all of the damage from strokes, head injury, hypoxia, polio, and a variety of other conditions. However, it seems that nature never gives something for nothing, and here too there was another side to the coin. The dream ended when Olney et al. demonstrated that animals given huge doses of dizocilpine (MK-801), a new dissociative used in research, showed curious vacuoles (essentially, tiny holes) in tissue samples in the posterior cingulate cortex and retrosplenial cortex of lab animals (174,177,180-182,217,307-308,323,329). Further research showed that other indicators of damage were present, such as proliferation of microglia and induction of a protein called HSP70 (Heat-Shock Protein 70) (173,325). Since then, Onley’s lesions, also known as NMDA Antagonist Neurotoxicity or NAN, have been discovered with ketamine (325), PCP (302), and dextrorphan (177), all nonco
