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The dopaminergic mechanisms that control reward-motivated behavior are the subject of intense study, but it is yet unclear how, in humans, neural activity in mesolimbic reward-circuitry and its functional neuroimaging correlates are related to dopamine release. To address this question, we obtained functional magnetic resonance imaging (fMRI) measures of(More)
Neurobiological mechanisms underlying the development of major depressive disorder (MDD) may differ depending on age-of-onset. Our aim was to compare patients who differ in age-of-onset, while controlling for illness duration, and number of depressive episodes. By directly comparing early-(EOD) and late-onset (LOD) patients, we examined whether age-of-onset(More)
The primary objective of this study was to verify the suitability of reference tissue-based quantification methods of the metabotropic glutamate receptor type 5 (mGluR(5)) with [(11)C]ABP688. This study presents in vivo (Positron Emission Tomography (PET)) and in vitro (autoradiography) measurements of mGluR(5) densities in the same rats and evaluates both(More)
Rationale. Alzheimer's Disease (AD) is a neurodegenerative condition characterized in part by deficits in cholinergic basalocortical and septohippocampal pathways. [(18)F]Fluoroethoxybenzovesamicol ([(18)F]FEOBV), a Positron Emission Tomography ligand for the vesicular acetylcholine transporter (VAChT), is a potential molecular agent to investigate brain(More)
There has arisen considerable interest in the study of dopamine D(2/3) agonist binding sites by positron emission tomography (PET), based on the claim that agonist sites represent a functional subset of the total number of sites labeled by more conventional antagonist ligands. To test the basis of this claim, we used quantitative autoradiography to measure(More)
We used microPET to map the dose-response to the novel P-glycoprotein (P-gp) inhibitor tariquidar (TQD) of the initial influx of the P-gp substrate [(18)F]-MPPF in rat brain, and to test for effects of P-gp inhibition on the subsequent binding of [(18)F]-MPPF to serotonin 5-HT(1A) receptors. Summation maps of [(18)F]-MPPF uptake during the first 100 seconds(More)
Depression is a brain disorder and there is still only a partial understanding of its underlying pathophysiology. Antidepressant medications with a fast onset have not yet been developed. In addition to the monoaminergic systems, the brain glutaminergic system has been implicated in the etiology of depression. Animal studies of depression have gained(More)
We have developed [(11)C]mirtazapine as a ligand for PET studies of antidepressant binding in living brain. However, previous studies have determined neither optimal methods for quantification of [(11)C]mirtazapine binding nor the pharmacological identity of this binding. To obtain that information, we have now mapped the distribution volume (V(d)) of(More)
The psychoactive properties of the hallucinogen LSD have frequently been attributed to high affinity interactions with serotonin 5HT2 receptors in brain. Possible effects of LSD on dopamine D2/3 receptor availability have not previously been investigated in living brain. Therefore, we used PET to map the binding potential (pB) of [11C]raclopride in brain of(More)
The pig has been used as animal model for positron emission tomography (PET) studies of dopamine (DA) receptors and pharmacological perturbations of DA neurotransmission. However, the binding properties of DA receptors and transporters in pig brain have not been characterized in vitro. Therefore, the saturation binding parameters of [3H]SCH 23390 for DA D1(More)