Several radiolabelled cocaine analogues have been proposed for brain imaging of the dopamine transporter in research on neuropsychiatric disorders and drug abuse. In a recent positron emission tomography (PET) study we labelled the cocaine analogue β-CIT-FE with carbon-11 and demonstrated high specific binding in the monkey striatum. In the present study, the selectivity of [""C]β-CIT-FE bindin...

The impact of dopamine on adaptive behavior in a naturalistic environment is largely unexamined. Experimental work suggests that phasic dopamine is central to reinforcement learning whereas tonic dopamine may modulate performance without altering learning per se; however, this idea has not been developed formally or integrated with computational models of dopamine function. We quantitatively ev...

The association between dietary obesity and mesolimbic systems that regulate hedonic aspects of feeding is currently unresolved. In the present study, we examined differences in baseline and stimulated central dopamine levels in obesity-prone (OP) and obesity-resistant (OR) rats. OP rats were hyperphagic and showed a 20% weight gain over OR rats at wk 15 of age, when fed a standard chow diet. T...

PURPOSE Dopamine has several important functions in the retina including a possible role in controlling photoreceptor disk shedding to the RPE. While some cells express a transporter for dopamine, the RPE cell does not, leading us to ask whether the newly described catecholamine transport system, the extraneuronal monoamine transporter (uptake(2)) (also known as organic cation transporter 3 (OC...

ISSUE Selective norepinephrine reuptake inhibitors exploit the fact that dopamine transporters are absent in prefrontal cortex, so dopamine has to hitchhike a ride on the norepinephrine transporter in order to be inactivated. Thus, blocking norepinephrine transporters leads to an increase in both dopamine and norepinephrine levels in prefrontal cortex as well as improvement in cognition in atte...

Cells of the exocrine pancreas produce digestive enzymes potentially harmful to the intestinal mucosa. Dopamine has been reported to protect against mucosal injury. In looking for the source of dopamine in the small intestine, we found that the duodenal juice contains high levels of dopamine and that the pancreas itself has a high dopamine [and dihydroxyphenylalanine (dopa)] content that does n...

The role of protein kinase C and intracellular Ca(2+) on amphetamine-mediated dopamine release through the norepinephrine plasmalemmal transporter in undifferentiated PC12 cells was investigated. The selective protein kinase C inhibitor chelerythrine completely inhibited endogenous dopamine release elicited by 1 microM amphetamine. Direct activation of protein kinase C increased dopamine releas...