Marinete Pinheiro Carrera

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In the study of behavioural sensitization induced by dopamine agonists, D1 and D2 receptors have a critical, but a puzzling role. The objective of this study is to examine the effects of the D1 antagonist SCH-23390 and the D2 antagonist sulpiride given repeatedly alone or in combination with apomorphine upon apomorphine conditioning and sensitization.(More)
High doses of apomorphine induce sensitization to locomotor stimulant effects whereas low doses induce locomotor inhibition. We examined whether repeated low dose apomorphine induced sensitization and conditioning to the locomotor inhibitory effect. Three doses of the D1/D2 agonist, apomorphine, were used in a Pavlovian conditioning protocol: 0.05 mg/kg(More)
Anti-psychotic drugs are antagonists of dopamine D2 receptors and repeated administration may lead to the development of dopamine receptor supersensitivity. The objective of this study is to investigate the effects of sub-chronic olanzapine treatments upon the induction of dopamine receptor supersensitivity. Rats were administered ten daily low or high(More)
Sensitization is a common feature of psychostimulants and sensitization effects are generally considered to be linked to the addictive properties of these drugs. We used a conventional paired/unpaired Pavlovian protocol to induce a context specific sensitization to the locomotor stimulant effect of a high dose of apomorphine (2.0mg/kg). Two days following a(More)
The present study examined the minimal number of exposures to the D1/D2 agonist apomorphine capable of producing behavioral sensitization. Rats received one (experiment 1) or two administrations on two successive days (experiment 2) of apomorphine (0.5 and 2.0 mg/kg) paired or unpaired to an open-field environment. After 2 days of drug withdrawal, the rats(More)
Low dose apomorphine treatments preferentially activate dopamine autoreceptors and inhibit dopamine neurons as well as behavior. In contrast, high doses of apomorphine induce locomotor stimulation by activating dopamine postsynaptic receptors. We compared the effects of low (0.05 mg/kg) vs. high (2.0 mg/kg) repeated apomorphine treatments (5) using(More)
Repeated treatments with psychostimulant drugs generate behavioral sensitization. In the present study we employed a paired/unpaired protocol to assess the effects of repeated apomorphine (2.0 mg/kg) treatments upon locomotion behavior. In the first experiment we assessed the effects of conditioning upon apomorphine sensitization. Neither the extinction of(More)
The present study examined the role of D(1) and D(2) receptors in the conditioning of apomorphine-induced locomotor behavior. A Pavlovian conditioning protocol was used in which rats received 5 daily intrastriatal apomorphine treatments paired or unpaired to an open-field environment followed, 2 days later, by a saline test for conditioning. In the(More)
Psychostimulant sensitization can have transformative effects upon contextual stimuli such as acquired conditioned stimuli and conditioned incentive motivational properties. The aim of this study is to induce apomorphine sensitization and conduct non-drug exposures to the contextual cues followed by post-trial treatments designed to associate(More)
Re-exposure to conditioned drug stimuli triggers re-consolidation processes. In the present study post-trial apomorphine treatments were administered in order to interact with the re-consolidation of an apomorphine conditioned/sensitized locomotor response. A low (0.05 mg/kg) and a high (2.0mg/kg) dose were used to inhibit or to enhance dopamine activity,(More)