Influence of chronic restraint stress on cocaine-induced glutamate release in the nucleus accumbens

GUZMAN, A.S.; AVALOS M.P; GARCIA KELLER, C; RIGONI, D.; BOLLATI, F.; CANCELA L.M.

Mar del plata

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

Sociedad Argentina de Investigación en Neurociencias

Cross-sensitization between stress and drugs ofabuse maybe explained by long-term neurobiological changes in themesocorticolimbic dopamine (DA) and glutamate(GLU) transmissions;specifically, within Nucleus Accumbens (NAc), the major limbic-motorintegration area.In this sense, previous results from our lab havedemonstrated that after two weeks of a single exposure torestraint stress achallenge of cocaine induced locomotor sensitization and a parallel increase inextracellularDA levels in Core compartment of NAc, meanwhile GLU levels inthis area were not modified. Thepresent study attempted to determinate thelong-term effect of chronic restraint stress pre-exposure inextracellularlevels of GLU in NAc Core in response to cocaine. Wistar rats were exposed to repeated(2hfor 7 days) restraint stress and two weeks after the last stress session,all animals were implanted withprobes of microdialysis in NAc Core. The dayafter surgery, GLU dialysate samples were collected andquantified by HPLC.After cocaine administration (15 mg/kg, i.p.), animals pre-exposed to chronic stressdidnot show increased extracellular glutamate levels in NAc Core, similarly toour results obtained following pre-exposure to acute stress. These findingscould be explained in the framework of a dysregulation of GLUhomeostasisinduced by stress. The current study provides neurochemical basis in order toinvestigate themechanisms underpinning the comorbidity between stress and drugabuse.