The NMDA antagonist, MK-801 blocks the expression of stress-induced reinstatement”.

7.DE GIOVANNI L., VIRGOLINI, M.B., CANCELA L.M.

Mar del Plata

Congreso; LV Reunión Anual de la Sociedad Argentina de Investigación Clínica. Reunión de la Sociedad Argentina de Fisiología. XLII Reunión Annual de la Sociedad Argentina de Farmacología Experimental; 2010

SAFE. SAIC

THE NMDA ANTAGONIST, MK 801,  BLOCKS THE EXPRESSION OF STRESS-INDUCED REINSTATEMENT    De Giovanni, Laura Noemi; Virgolini, Miriam Beatriz, Cancela, Liliana Marina. luli_deyo@yahoo.com.ar Recent studies of our laboratory demonstrate that the NMDA antagonist MK 801 given 15 min before the a single stress session of 30 min induce a long lasting blockage  in the stress-induce reinstatement and in the subsecuents cocaine-induce reinstatement 3 and 10 days after the first reinstatement , in animals  previously conditioned with cocaine. Besides, we demonstrate that MK 801 by itself  induce reinstatement in the first reinstatement test, but 3 and 10 days after show blockage in the subsequent cocaine-induce reinstatement, supporting the idea that MK 801 blocks the reinstatement induced by stress , cocaine and context. In order to demonstrate that the effect of MK 801 is specific  and is not a effect  anxiolytic on stress, Male wistar rats was conditioned and then extinguished following the CPP reinstatement procedure, in the reinstatement day the animals were separated in two diferents groups , with or without a single stress session of 30min. After that the animals come back at their homecage and receive MK 801 (0.1 mg/kg) or VEH and 15 min later were tested in the CPP. We demonstrate that all the animals that receive MK 801 shows blockage in the stress or context -induce reinstatement and in the subsequent cocaine-induce reinstatement. These results support the hypothesis  that the blockage induced by MK 801 is a specific effect  on the reward pathway and this blockage is long lasting 3 and 10 days in response to a priming dose of cocaine , given more evidence to neurobiological shared mechanism between cocaine and stress in the reinstatement.