Blockade of the metabotropic glutamate 2/3 receptors enhances social memory via the AMPA receptor in rats.

The present study examined the role of mGlu(2/3) receptors in short-term social memory using the social recognition paradigm in rats in which an adult rat is exposed to the same juvenile rat in two successive interactions. Intraperitoneal administration of the mGlu(2/3) receptor antagonist MGS0039 (0.3-3 mg/kg) or the ampakine CX546 (0.3-3 mg/kg) significantly and dose-dependently reduced the adult rat's social investigation of the same juvenile rat during the second encounter which occurred 120 min after the first encounter, indicating that both MGS0039 and CX546 enhanced social recognition. Pretreatment with the AMPA receptor antagonist NBQX (0.1-1 mg/kg, s.c.) significantly attenuated the effects of MGS0039 (3 mg/kg, i.p.) in the social recognition test. These results suggest that the mGlu(2/3) receptor blockade increases social recognition memory, presumably through stimulation of the AMPA receptor.