INFLUENCE OF CHRONIC RESTRAINT STRESS ON COCAINE-INDUCED GLUTAMATE RELEASE IN THE NUCLEUS ACCUMBENS

GUZMAN ANDREA SUSANA; AVALOS MARIA PAULA; GARCIA-KELLER CONSTANZA; RIGONI DAIANA; BOLLATI FLAVIA; CANCELA LILIANA M

Mar del Plata

Congreso; XXXII Congreso de la Sociedad Argentina de Investigación en Neurociencias. Congreso International.; 2017

Sociedad Argentina de Investigación en Neurociencias

Cross-sensitization between stress and drugs of abuse may be explained by long-term neurobiological changes in the mesocorticolimbic dopamine (DA) and glutamate (GLU) transmissions; specifically, within Nucleus Accumbens (NAc), the major limbic-motor integration area. In this sense, previous results from our lab have demonstrated that after two weeks of a single exposure to restraint stress a challenge of cocaine induced locomotor sensitization and a parallel increase in extracellular DA levels in Core compartment of NAc,meanwhile GLU levels in this area were not modified. The present study attempted todeterminate the long-term effect of chronic restraint stress pre-exposure in extracellular levels of GLU in NAc Core in response to cocaine. Wistar rats were exposed to repeated (2h for 7 days) restraint stress and two weeks after the last stress session, all animals were implanted with probes of microdialysis in NAc Core. The day after surgery, GLU dialysate samples were collected and quantified by HPLC. After cocaine administration (15 mg/kg, i.p.), animals pre-exposed to chronic stress did not show increased extracellular glutamate levelsin NAc Core, similarly to our results obtained following pre-exposure to acute stress. These findings could be explained in the framework of a dysregulation of GLU homeostasis induced by stress. The current study provides neurochemical basis in order to investigate the mechanisms underpinning the comorbidity between stress and drug abuse.