Resumo

The reconsolidation is a phenomenon that enables changes in maladaptive memories and memory related to drug abuse. One of the factors related to relapse is the development of behavioral sensitization, which is mediated by the action of the dopaminergic system. The mechanism of action common to most drugs of abuse is the increase in dopaminergic activation, which overloads the system of motivation and affect brain circuits like memory. The aim of this study was to investigate whether pharmacological manipulations in the memory reconsolidation held by administrations of D1/D2 apomorphine agonist (APO) at doses of 0.05 mg / kg (activates presynaptic receptors, decreasing the locomotion) and 2.0 mg / kg (acts on postsynaptic receptors, increasing mobility) immediately after the conditioning test will facilitate or hinder the expression of behavioral sensitization process. For this, rats received APO (2.0 mg / kg SC) in two situations: paired (APO-P, n = 20) and unpaired (APO-UP, n = 20) to the experimental environment for 5 days, which was the induction phase (IP), and locomotion was recorded for 30 minutes. The control group received vehicle (APO-VEH, n = 20). Following a withdrawal period of 2 days, we administered saline (reconsolidation test, RT) and locomotor activity was recorded for 5 minutes. Immediately after the reconsolidation test, the animals of the groups paried, unpaired and vehicle were subdivided into three subgroups that received APO (0.05 or 2.0 mg / kg) or vehicle, being formed as follows: Paried (2.0 , 0.05 and vehicle), Unparied (2.0, 0.05, vehicle), Vehicle (2.0, 0.05 and vehicle). After a withdrawal period, were administered APO 2.0 mg / kg (sensitization test, ST). The control group received vehicle. The results showed that the induction phase, increased locomotion only for the paried group, and this increase was progressive, showing the development of sensitization. In the reconsolidation test, results showed that only the paried group showed an increase in locomotion, suggesting the expression of conditioning. In ST, the results showed the paried group that received apomorphine 2.0 mg/ kg immediately after the test reconsolidation showed higher locomotion that all groups, even higher than the paried group with that after the reconsolidation test received vehicle, suggesting a facilitating the expression of sensitization. In contrast, the paried group that received apomorphine 0.05 mg/kg immediately after the reconsolidation test showed locomotion equivalent to groups unpaired and the vehicle group, suggesting an impairment in the expression of sensitization. The results showed that an increase in learning with the higher dose facilitated the sensitization that while a weakening produced with the low dose impaired the expression of sensitization. Pharmacological manipulations in the reconsolidation of memory could serve as therapeutic targets in drug abuse.