Efeito da pré-exposição a dietilpropiona e a cafeína sobre o valor reforçador da dietilpropiona / Effect of pre-exposure to diethylpropion or caffeine on the reinforcing value of diethylpropion

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Recent literature considers sensitization resulting from pre-exposure to psychostimulants as a possible factor in drug addiction acquisition, maintenance and relapse. The aim of this study was to verify if pre-exposure to the psychostimulants diethylpropion (DEP) and caffeine (DEP) would sensitize rats to the reinforcing value of DEP. Four experiments were conducted. In Experiment 1 a group of rats was pre-exposed to DEP while another group received vehicle. After that, the acute effect of i.p. DEP (1.0, 2.5 or 5.0 mg/kg) on motor activity was measured. A similar pre-exposure procedure was conducted in Experiment 2. After that, Conditioned Place Preference (CPP) induced by i.p. DEP (1.0, 2.5 or 5.0 mg/kg) was measured. Experiment 3 was subdivided in two parts. In the first one adult rats were pre-exposed to i.p. CAF while a control group received vehicle. After that, CPP induced by 2.5 mg/kg i.p. DEP was measured. In the second part of this experiment, adolescent rats were pre-exposed to oral CAF for 56 consecutive days, while a control group received water. After that, CPP induced by 1.0 mg/kg i.p. DEP was measured. In Experiment 4, adolescent rats were submitted to a pre-exposure procedure similar to that described for the second part of Experiment 3. After that, their responses reinforced by a DEP solution on a progressive ratio schedule (PR) were measured. Experiment 1 results showed that 2.5 and 5.0 mg/kg DEP increased motor activity. At 5.0 mg/kg this effect was more pronounced in pre-exposed animals. In Experiment 2, the doses of 2.5 and 5.0 mg/kg DEP induced CPP, demonstrating their reinforcing value. However, no sensitization effect was observed. Experiment 3 results revealed that neither pre-exposure to oral CAF from adolescence to adulthood nor i.p. CAF pre-exposure in adulthood sensitized DEP reinforcing value as measured by CPP. Experiment 4 results showed that oral CAF pre-exposure from adolescence to adulthood induced sensitization of DEP reinforcing value as measured by PR breaking point. Results are discussed in terms of the animal models to assess reinforcing value, the abuse potential of DEP and the relevance of early caffeine consumption on the vulnerability to drug dependence.

ASSUNTO(S)

desempenho motor dietilpropiona sensibilização amphetamine diethylpropion anfetamina drug abuse reforço cafeina caffeine droga (abuso) reinforcement motor performance sensitization

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