INVESTIGADORES
CALFA Gaston Diego
congresos y reuniones científicas
Título:
Cocaine decreases ABPs phosphorilation and increases AMPA surface expression in rat nucleus accumbens following chronic stress.
Autor/es:
ESPARZA, M.A.; GARCIA KELLER, C.; VIRGOLINI, M.; CALFA, G.; KALIVAS, P.W., CANCELA L.M
Reunión:
Congreso; II International Workshop: "Motivated behavior stress and addiction; 2012
Resumen:
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 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 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). Male wistar
rats were restrained daily (2 hours) for 7 days, and
three weeks later, the NAc was dissected 45 min following acute saline or
cocaine (30 mg/kg i.p. or 15 mg/Kg). F-actin, ABPs and AMPAR were determined by western blotting. Locomotor activity was monitored
in a photocell apparatus and quantified as total photocell counts. For these
sessions, animals were allowed to habituate to the activity chambers before
latrunculin A or DMSO (1%) microinjections, which were followed by cocaine (15
mg/kg, i.p.) or saline. 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. This study
shows that a history of repeated stress alters the ability of a subsequent
cocaine injection to modulate the reorganization of
synaptic connections, actin cytoskeleton and AMPAR expression in the NAc.