BEHAVIORAL-EFFECTS MEDIATED BY THE MODULATORY GLYCINE SITE OF THE NMDA RECEPTOR IN THE ANTERODORSAL STRIATUM AND NUCLEUS-ACCUMBENS

The striatum and the nucleus accumbens are the main input structures o f the basal ganglia (BG). They contribute differently to motor behavio r controlled by the BG in rats, e.g., stereotyped behavior, catalepsy, and locomotion. Whereas the striatum is predominantly involved in the control of sniffing behavior and catalepsy, the nucleus accumbens con tributes to control of locomotion. To test whether the allosteric glyc ine site of the NMDA receptor complex modulates these behavioral varia bles, we injected the glycine-site antagonist 7-chlorokynurenate and t he glycine-site agonist D-serine into the anterodorsal striatum and th e nucleus accumbens and studied their influence on stereotypical snout contacts and locomotion. Additionally, the effects of intrastriatal i njections of 7-chlorokynurenate on haloperidol- and SCH 23390-induced catalepsy were investigated. 7-Chlorokynurenate enhanced stereotypical snout contacts in the anterodorsal striatum and in the nucleus accumb ens but did not change spontaneous locomotion in either of these struc tures. Haloperidol- but not SCH 23390-induced catalepsy was attenuated by intrastriatally administered 7-chlorokynurenate. The glycine-site agonist D-serine had no effect on stereotypical snout contacts and loc omotion. The results suggest that motor behavior mediated by the stria topallidal output pathway is modulated by the glycine site, whereas mo tor behavior mediated by the accumbopallidal and striatonigral output pathway is not.