GRN-529
GRN-529 is a drug that was developed by Wyeth as a negative allosteric modulator of the metabotropic glutamate receptor 5.
A study conducted by Pfizer found that GRN-529 reduced repetitive behaviors without sedation and partially increased sociability in mouse models of autism.
Another study conducted by Pfizer found a therapeutically relevant effect in animal models of depression. It is theorized to work by reducing glutamate receptor hyperactivity.