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Repeated cocaine treatment and withdrawal produces changes in brain function thought to be involved in relapse to drug use. Withdrawal from repeated cocaine reduced in vivo extracellular glutamate in the nucleus accumbens of rats by decreasing the exchange of extracellular cystine for intracellular glutamate. In vivo restoration of cystine/glutamate(More)
To examine neuronal activation associated with incentive motivation for cocaine, cocaine-seeking behavior (operant responding without cocaine reinforcement) and Fos expression were examined in rats exposed to saline and cocaine priming injections and/or a self-administration environment. Rats were first trained to self-administer cocaine or received yoked(More)
Basal extracellular glutamate sampled in vivo is present in micromolar concentrations in the extracellular space outside the synaptic cleft, and neither the origin nor the function of this glutamate is known. This report reveals that blockade of glutamate release from the cystine-glutamate antiporter produced a significant decrease (60%) in extrasynaptic(More)
Cocaine and cocaine-associated cues elicit craving in addicts and reinstate cocaine-seeking behavior in rats. Craving and cocaine-seeking behavior may be mediated by withdrawal-induced changes in dopamine (DA) neurotransmission in the amygdala. To examine whether there are concomittant changes in cocaine-seeking behavior and extracellular DA levels during(More)
The present study aimed to characterize a functional role for group I metabotropic glutamate receptors (mGluRs) in the nucleus accumbens and the capacity of repeated cocaine to elicit long-term changes in group I mGluR function. Reverse dialysis of the group I agonist (RS)-3,5-dihydroxyphenylglycine (DHPG) into the nucleus accumbens resulted in an increase(More)
Repeated cocaine produces enduring neuroadaptations in glutamate transmission in the nucleus accumbens that are thought to contribute to addiction. Group II metabotropic glutamate autoreceptors (mGluR2/3) regulate glutamate release, and this study investigates whether repeated cocaine injection produces long-lasting alterations in mGluR2/3 content,(More)
Rationale: Clinical studies examining the efficacy of the selective serotonin reuptake inhibitor, fluoxetine, in decreasing craving and cocaine use have been inconsistent. Objective: To understand better the effects of fluoxetine treatment on incentive motivation for cocaine, the present study assessed the effects of chronic fluoxetine treatment on(More)
Repeated cocaine alters glutamate neurotransmission, in part, by reducing cystine-glutamate exchange via system xc-, which maintains glutamate levels and receptor stimulation in the extrasynaptic compartment. In the present study, we undertook two approaches to determine the significance of plasticity involving system xc-. First, we examined whether the(More)
The parasitic flagellate Giardia is the source of a filamentous protein, giardin, which binds to microtubules. The primary sequence of one giardin chain has been decoded from the base sequences of cDNAs isolated by antibody screens of a library constructed in the expression vector lambda gt11. The amino acid sequence favours a continuous alpha-helical fold(More)