The glutamate homeostasis in NAc Core after the cross-sensitization induced by stress twenty one days earlier: the role of glutamate transporter GLT-1 in astrocytes.

GARCÍA KELLER, C; ESPARZA, A; KALIVAS, PW; CANCELA, L.M

Huerta Grande

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Neurociencia; 2012

Sociedad Argentina de Imvestigacion en Neurociencia

Sensibilizationisassociatedwithneuroplasticity in the dopaminergic (DA) and glutamatergic (Glu) mesocorticolimbic systems.Itiswellknowthatwithdrawal (2-3 weeks)fromchroniccocaine, induced-changein synapticglutamatetransmission and glutamate transporter-1 (GLT-1)expression in theNAc. Theaim of ourstudywastoevaluatedtheparticipation of GLT-1 in Glu homeostasis and howthisaffectscocaine-induce Glusynaptic reléase in pre-stressedanimals.Male Wistar rats (250-350 g) were restrained for two hours, while control animals were left undisturbed in their cages. Twenty-one days after this stress episode, animals were assigned to one of the following experiments: I) Microdialysis: Glu release was measured by HPLC in NAc Core and NAc Shell in response to saline and cocaine (15 mg/kg i.p.); and basal Glu levels were measured by no-net-flux technique. II) Western blot: GLT-1 expression in NAc Core after i.p. injection of saline or cocaine (15 mg/kg).Our results demonstrate that pre-stressed animals,restrainted 3 weeks before, showed increased basal levels of Glu in Core, but not shell, and blunted the increase by acute cocaine challenged. The alterations in basal and extracellular Glu appeared consequential from GLT-1 decreased expression in Core in the treated group.