EFFECT OF INTRA-CORE METABOTROPIC RECEPTORS GROUP I (mGlu I) ANTAGONIST AND GROUP II (mGlu II) AGONIST ADMINISTRATION IN THE STRESS-INDUCED REINSTATEMENT IN EXTINGUISHED COCAINE-CONDITIONED ANIMALS

DE GIOVANNI, LN; GUZMÁN, AS; VIRGOLINI, MB; CANCELA, LM

Córdoba

Encuentro; V Encuentro de Jóvenes Investigadores en Neurociencias; 2013

Jóvenes Investigadores en Neurociencias - UNC

Previous results from our lab showed that the intra-core administration of metabotropic group I (mglu I) antagonist and metabotropic group II (mglu II) agonist blocked the stress-induced reinstatement in an extinguished cocaine-induced conditioned place preference (CPP) in rats. Moreover we determine that animals which were injected systemically with MK 801 (NMDA antagonist) but follow this injection did not were exposed to the CPP apparatus (no contingent administration) did not show the blockade of stress-induced reinstatement. In the present experiments, our goal was to determine if a no contingent intra-core administration of LY 479234 (mglu II agonist) or MPEP (mglu I antagonist) could influence the stress-induced reinstatement. Male Wistar rats (220-300g) were conditioned with cocaine (10 mg/kg i.p.) during four alternated drug/vehicle sessions, and later extinguished with successive vehicle associations. The following day, animals were microinfunded with MPEP (1 ug/side), LY 479234 (0.5 ug/side) or vehicle and, after the administration they were left undisturbed in their home cages. Two days after the same animals were exposed to a 30 min-restraint exposure, and then were tested in the CPP. Results demonstrate that, neither MPEP nor LY 479234 did not exert and influence in the stress-induced reinstatement when the animals were infuded in a non-contingent way. These results suggest that the blockade of stress-induced reinstatement in extinguished cocaine conditioned animals induced by MPEP or LY 479234 requires a contingency relationship, with the CPP exposure. This result support the hypothesis that the involvement of a nucleus accumbens core in the stress-induced reinstatement depends of the contingency between the agonist/antagonist administration and the CPP exposure.