<Li> Ibotenic acid--naturally occurring glutamate site agonist found in Amanita muscaria </Li> <Li> Milacemide--synthetic glycine site agonist; prodrug of glycine </Li> <Li> Quinolinic acid (quinolinate)--endogenous glutamate site agonist </Li> <Li> Sarcosine--endogenous glycine site agonist </Li>

The ndma receptor is involved in which of the following processes