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B Weber

Bio: B Weber is an academic researcher. The author has contributed to research in topics: Dopaminergic & Neurotransmitter. The author has an hindex of 1, co-authored 1 publications receiving 339 citations.

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TL;DR: It was found that daily amphetamine injection into the A10 or A9 dopamine region, but not into the dopamine terminal fields, significantly potentiated the motor stimulant effect of peripherally administered amphetamine.
Abstract: The daily administration of indirect dopamine agonists, including amphetamine and cocaine, results in a progressive increase in the behavioral stimulant effect of these drugs. Behavioral augmentation also has been shown with opioids such as morphine, and it is known that a stimulant action on dopaminergic perikarya in the ventromedial mesencephalon is critical to the development of behavioral sensitization to morphine. To determine if amphetamine-induced behavioral sensitization might also involve the mesencephalic dopamine neurons, amphetamine was microinjected daily for 2 days into regions of the rat brain containing dopamine cell bodies (A10 and A9 dopamine regions), or dopamine terminals (nucleus accumbens and striatum), and 6 days later amphetamine was given peripherally. It was found that daily amphetamine injection into the A10 or A9 dopamine region, but not into the dopamine terminal fields, significantly potentiated the motor stimulant effect of peripherally administered amphetamine. The behavioral sensitization produced by intracranial injection of amphetamine was found to be dose-dependent. Intra-A10 injection of amphetamine also was found to potentiate the motor stimulant effect of peripheral cocaine. These data indicate that an action by amphetamine in the A10 and A9 dopamine regions may play a critical role in the development of behavioral sensitization.

344 citations


Cited by
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TL;DR: It is found that the dopamine neurons of sensitized animals have become increasingly sensitive to excitatory pharmacological and environmental stimuli or desensitized to inhibitory regulation, and changes in cellular activity or protein synthesis may result in a change in the presynaptic regulation of axon terminal dopamine release.

2,042 citations

Journal ArticleDOI
TL;DR: The distinctions between drugs in the induction and expression of sensitization indicate that behavioral sensitization can arise from multiple neuroadaptations in multiple brain nuclei, not only the result of distinct molecular targets for the drugs, but may also include a differential involvement of learned associations.
Abstract: Rationale and objectives: Repeated exposure to many drugs of abuse results in a progressive and enduring enhancement in the motor stimulant effect elicited by a subsequent drug challenge. This phenomenon, termed behavioral sensitization, is thought to underlie certain aspects of drug addiction. Behavioral sensitization is the consequence of drug-induced neuroadaptive changes in a circuit involving dopaminergic and glutamatergic interconnections between the ventral tegmental area, nucleus accumbens, prefrontal cortex and amygdala. Methods: The literature was critically reviewed in an effort to discern the relative roles of glutamate and dopamine transmission in the induction and expression of sensitization to amphetamine, cocaine and µ-opioids. In addition, the literature was reviewed to evaluate distinctions between these drugs in the involvement of the relevant brain nuclei listed above. Results: The common substrates between sensitizing drugs are glutamate transmission, especially at the NMDA receptor, and an action in the ventral tegmental area. In contrast, a role for dopamine is only clearly seen in amphetamine sensitization and critical involvement of nuclei outside the ventral tegmental area is found for cocaine and morphine. While enhanced dopamine transmission is associated with sensitization by all three drugs, a role for glutamate is clearly identified only with cocaine sensitization. Accordingly, glutamatergic cortical and allocortical brain regions such as the prefrontal cortex appear more critical for cocaine sensitization. Conclusions: The distinctions between drugs in the induction and expression of sensitization indicate that behavioral sensitization can arise from multiple neuroadaptations in multiple brain nuclei. This is not only the result of distinct molecular targets for the drugs, but may also include a differential involvement of learned associations. It is postulated that the relatively more robust pharmacological capacity of amphetamine to release dopamine may induce a form of sensitization that is more dependent on adaptations in mesoaccumbens dopamine transmission compared with cocaine and morphine sensitization.

1,327 citations

Journal ArticleDOI
01 Mar 2000-Neuron
TL;DR: This dissertation aims to provide a history of web exceptionalism from 1989 to 2002, a period chosen in order to explore its roots as well as specific cases up to and including the year in which descriptions of “Web 2.0” began to circulate.

1,179 citations

Journal ArticleDOI
TL;DR: The evidence supports the hypothesis that under certain circumstances rats can become sugar dependent and may translate to some human conditions as suggested by the literature on eating disorders and obesity.

1,171 citations

Journal ArticleDOI
TL;DR: A review of the large number of subsequent studies addressing the roles of NMDA, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and metabotropic glutamate receptors in the development and expression of behavioral sensitization concludes that EAA projections originating in prefrontal cortex may play a particularly important role in theDevelopment of sensitization.

936 citations