Expression of Stress-Induced Sensitization to Cocaine is Associated to Changes in ABPs and GluR1 in the Nucleus Accumbens

MARÍA ALEJANDRA ESPARZA; MIRIAM B. VIRGOLINI; LILIANA M. CANCELA

Huerta Grande

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

SAN

Behavioral sensitization is an example of experience-dependent plasticity, induced by drug or stress, which has been suggested to involve plasticity at glutamatergic synapses and and there is evidence for a common mechanism triggered by stress and drugs at excitatory synapses on midbrain dopamine neurons. These experiments evaluated how the expression of restraint stress-induced sensitization to cocaine (15 mg/kg i.p.) is associated to alterations in actin binding proteins (ABPs) and the surface expression of GluR1 in nucleus accumbens (NAc). Our experiments revealed a decrease in p-cofilin and p-cortactin, and an increase in GluR1, in the stress plus cocaine group as was previously shown after cocaine (30 mg/kg). The stress-induced sensitization to cocaine was prevented by either latrunculin A or CNQX. Interestingly, latrunculin A also reversed the stress/cocaine-induced increase in GluR1, indicating a potential role for actin cytoskeleton in the increased AMPAR. This study shows that a history of repeated stress alters the ability of a subsequent cocaine injection to modulate dendritic spine morphology, actin dynamics and AMPAR expression in the NAc. Furthermore, by regulating AMPAR expression, elevated actin cycling contributes to the expression of cross-sensitization.