Volkow ND, Wang GJ, Telang F, Fowler JS, Thanos PK, Logan J et al. Low dopamine striatal D2 receptors are associated with prefrontal metabolism in obese subjects: possible contributing factors. NeuroImage 42: 1537-1543

National Institute on Drug Abuse, Bethesda MD 20892, USA.
NeuroImage (Impact Factor: 6.36). 06/2008; 42(4):1537-43. DOI: 10.1016/j.neuroimage.2008.06.002
Source: PubMed


Dopamine's role in inhibitory control is well recognized and its disruption may contribute to behavioral disorders of discontrol such as obesity. However, the mechanism by which impaired dopamine neurotransmission interferes with inhibitory control is poorly understood. We had previously documented a reduction in dopamine D2 receptors in morbidly obese subjects. To assess if the reductions in dopamine D2 receptors were associated with activity in prefrontal brain regions implicated in inhibitory control we assessed the relationship between dopamine D2 receptor availability in striatum with brain glucose metabolism (marker of brain function) in ten morbidly obese subjects (BMI>40 kg/m(2)) and compared it to that in twelve non-obese controls. PET was used with [(11)C]raclopride to assess D2 receptors and with [(18)F]FDG to assess regional brain glucose metabolism. In obese subjects striatal D2 receptor availability was lower than controls and was positively correlated with metabolism in dorsolateral prefrontal, medial orbitofrontal, anterior cingulate gyrus and somatosensory cortices. In controls correlations with prefrontal metabolism were not significant but comparisons with those in obese subjects were not significant, which does not permit to ascribe the associations as unique to obesity. The associations between striatal D2 receptors and prefrontal metabolism in obese subjects suggest that decreases in striatal D2 receptors could contribute to overeating via their modulation of striatal prefrontal pathways, which participate in inhibitory control and salience attribution. The association between striatal D2 receptors and metabolism in somatosensory cortices (regions that process palatability) could underlie one of the mechanisms through which dopamine regulates the reinforcing properties of food.

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    • "As such, differences in reactivity to external food cues may relate to propensities of weight gain, overweight and obesity. Food consumption is mediated by physiological hunger as well as by its rewarding properties (Volkow et al., 2008), indicating that human eating behaviours are driven by the interaction of need (homeostasis ) and want (reward). The incentive value of food, the allocation of attention towards foods when they are presented, and the motivation which drives subsequent efforts to obtain available food rewards are mediated by complex interactions within key brain areas: the amygdala/hippocampus, insular cortex, orbitofrontal cortex, and the striatum (Dagher, 2009). "
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    Appetite 11/2014; 85. DOI:10.1016/j.appet.2014.11.012 · 2.69 Impact Factor
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    • "In addition, we showed that the dopamine D2 receptor content was decreased in the nucleus accumbens of the SL animals. It is shown in humans that striatal dopamine D2 receptor availability is lower in obese individuals compared to controls [51] [52] [53]. We had previously demonstrated that the SL animals had increased abdominal fat deposition in adulthood [42], which is in agreement with other rodent data showing that abdominal obesity is associated with diminished D2 availability in striatal areas [54] [55]. "
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    • "Interestingly, DA-system integrity may be influenced by lifestyle factors. For example, cognitive and physical training increase dopaminergic measures , such as extracellular levels and receptor expression (Bäckman et al., 2011; de Castro and Duncan, 1985; Gilliam et al., 1984; MacRae et al., 1987; McNab et al., 2009; Vuckovic et al., 2010), whereas depression and obesity are associated with reductions (Meyer et al., 2001; Wang et al., 2001; Volkow et al., 2008). When it comes to heritage, normal genetic variants induce interindividual variability in brain and cognition (Knickmeyer et al., 2014; Lindenberger et al., 2008; Malhotra et al., 2002; Nyberg et al., 2013). "
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