biological role NMDA receptor antagonist NMDA receptor antagonists NMDAR antagonists N-methyl-D-aspartate receptor antagonists CHEBI:60797 chebi_ontology N-methyl-D-aspartate receptor antagonist NMDAR antagonist Any substance that inhibits the action of N-methyl-D-aspartate (NMDA) receptors. They tend to induce a state known as dissociative anesthesia, marked by catalepsy, amnesia, and analgesia, while side effects can include hallucinations, nightmares, and confusion. Due to their psychotomimetic effects, many NMDA receptor antagonists are used as recreational drugs. excitatory amino acid antagonist N-methyl-D-aspartate selective glutamate receptor activity