The present study investigated if blockade of the modulatory glycine receptor of the NMDA receptor complex influences the expression of behavior (sniffing stereotypy and locomotion) and dopamine metabolism in rats as it has been shown for NMDA receptor antagonists. The glycine receptor antagonist, 7-chlorokynurenate (7-chloro-4-hydroxyquinoline-2-carboxylic acid), induced a dose-dependent sniffing stereotypy but had no effect on locomotion when it was given i.c.v. The glycine receptor agonist, D-cycloserine (D-4-amino-3-isoxazolidinone), antagonized the sniffing stereotypy. 7-Chlorokynurenate had no influence on dopamine metabolism in the striatum and the nucleus accumbens, but moderately decreased the metabolism in the prefontal cortex. Comparison of behavioral and neurochemical outcomes suggests that the failure to induce locomotion correlates with the unchanged dopamine metabolism in the basal ganglia, while sniffing stereotypy does not. These result show that blockade of the glycine receptor of the NMDA receptor complex induces a behavioral and neurochemical profile similar to that of competitive NMDA receptor antagonists.
