P72.-Effect of Intra-Core, but Not Intra-Shell, mGlu I Antagonist Administration in Restraint Stress-Induced Reinstatement on Extinguished Cocaine-Conditioned Animals
Laura Noemi De Giovanni, Miriam Beatriz Virgolini, Liliana Marina Cancela
IFEC-CONICET; Dpto de Farmacologia- Facultad de Cs Quimicas, UNC, ARgentina
degiovannilaura.n@gmail.com
Previous results from our lab showed that intra-core administration of an mGlu II receptor agonist, LY479234, modified restraint stress-induced reinstatement in extinguished cocaine-induced conditioned place preference (CPP) in rats. Since several studies suggest that group I metabotropic glutamatergic receptors (mGlu I), are involved in cocaine reward the goal of the current study was determine if these receptors also exert an influence in restraint-stress induced reinstatement. In the present experiments, we determine if the intra-core vs. intra-shell administration of MPEP (mGlu I antagonist) could differentially influence the stress-induced reinstatement. Male Wistar rats were conditioned with cocaine (10 mg/kg i.p.) during four alternated drug/vehicle sessions, and extinguished with successive vehicle associations. The following day, animals were microinfused, intra-core or intra-shell, with MPEP (1 or 10 ug/side) or vehicle and 5 min later exposed to a 30 min restraint-stress session (Stress animals) or left undisturbed in their home-cages (Non-Stress animals). Results demonstrate that, the intra-core administration of LY 479234 blocked the restraint stress-induced reinstatement, while the intra-shell administration did not exert any influence. The current results support the hypothesis of the specific participation of mGlu I receptors of Nucleus Accumbens Core how a possible mechanism to understand stress-triggered reinstatement in extinguished cocaine-conditioned.
