Protein-Restricted Diets for Ameliorating Motor Fluctuations in Parkinson's Disease

Wang, Luxi; Xiong, Nian; Huang, Jinsha; Guo, Shichao; Liu, Ling; Han, Chao; Zhang, Guoxin; Jiang, Haiyang; Ma, Kai; Xia, Yun; Xu, Xiaoyun; Li, Jie; Liu, Jing Y.; Wang, Tao

doi:10.3389/fnagi.2017.00206

Cited by 48 publications

(41 citation statements)

References 74 publications

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“…Also, tmax is usually measured after over-night fasting, whereas subjects in the current study were not fasted to avoid fasting-related effects on behavior. This may have delayed L-dopa effects in this study due to slower gastric emptying and increased competition between L-dopa and dietary amino acids for active transport across the intestine and blood-brain barrier (Baruzzi et al, 1987;Contin & Martinelli, 2010;Wang et al, 2017).…”

Section: Neural Da Drug Effectsmentioning

confidence: 94%

Dopaminergic modulation of the exploration/exploitation trade-off in human decision-making

Chakroun

Mathar

Wiehler

et al. 2019

Preprint

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Acknowledgements: This work was funded by Deutsche Forschungsgemeinschaft (grant PE1627/5-1 to J.P.). Large parts of this publication are based on the dissertation "Dopaminergic modulation of the explore/exploit trade-off in human decision making" by K.C. (Chakroun, Karima: Dopaminergic modulation of the explore/exploit trade-off in human decision making [online]; Hamburg, Univ., Diss., 2019; Summary A central issue in reinforcement learning and decision-making is whether to exploit knowledge of reward values, or to explore novel options. Although it is widely hypothesized that dopamine neurotransmission plays a key role in regulating this balance, causal evidence for a role of dopamine in human exploration is still lacking. Here, we use a combination of computational modeling, pharmacological intervention and functional magnetic resonance imaging (fMRI) to test for a causal effect of dopamine transmission on the exploration-exploitation trade-off in humans. 31 healthy male subjects performed a restless four-armed bandit task in a within-subjects design under three drug conditions: 150mg of the dopamine precursor L-dopa, 2mg of the D2 receptor antagonist haloperidol, and placebo. In all conditions, choice behavior was best explained by an extension of an established Bayesian learning model accounting for perseveration, uncertainty-based exploration and random exploration. Uncertainty-based exploration was attenuated under L-dopa compared to placebo and haloperidol. There was no evidence for a modulation of prediction error signaling or categorical effects of exploration/exploitation under L-dopa, whereas model-based fMRI revealed that L-dopa attenuated neural representations of overall uncertainty in insula and dorsal anterior cingulate cortex. Our results highlight the computational role of these regions in exploration and suggest that dopamine modulates exploration by modulating how this circuit tracks accumulating uncertainty during decision-making.

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Section: Neural Da Drug Effectsmentioning

confidence: 94%

Dopaminergic modulation of the exploration/exploitation trade-off in human decision-making

Chakroun

Mathar

Wiehler

et al. 2019

Preprint

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“…Health professionals started to integrate dietary modifications for some neurological conditions, such as headaches [ 1 ], with positive results. Other conditions may directly (for example, drug-resistant epilepsy) [ 2 ] or indirectly (for example, Parkinson’s disease drug therapy) [ 3 ] depend on CAMs for their clinical outcome. Beyond their medical use, CAMs are often misused by patients [ 4 ], thus, possibly causing adverse effects, drug interactions, and a needless waste of money [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Dietary Neurotransmitters: A Narrative Review on Current Knowledge

et al. 2018

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Foods are natural sources of substances that may exert crucial effects on the nervous system in humans. Some of these substances are the neurotransmitters (NTs) acetylcholine (ACh), the modified amino acids glutamate and γ-aminobutyric acid (GABA), and the biogenic amines dopamine, serotonin (5-HT), and histamine. In neuropsychiatry, progressive integration of dietary approaches in clinical routine made it necessary to discern the more about some of these dietary NTs. Relevant books and literature from PubMed and Scopus databases were searched for data on food sources of Ach, glutamate, GABA, dopamine, 5-HT, and histamine. Different animal foods, fruits, edible plants, roots, and botanicals were reported to contain NTs. These substances can either be naturally present, as part of essential metabolic processes and ecological interactions, or derive from controlled/uncontrolled food technology processes. Ripening time, methods of preservation and cooking, and microbial activity further contributes to NTs. Moreover, gut microbiota are considerable sources of NTs. However, the significance of dietary NTs intake needs to be further investigated as there are no significant data on their bioavailability, neuronal/non neuronal effects, or clinical implications. Evidence-based interventions studies should be encouraged.

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“…Consumption of protein-rich meals may interfere with levodopa absorption and contribute to motor complications, primarily through competition of large neutral amino acids (eg, phenylalanine, tyrosine, and tryptophan) with levodopa for specific active-transport systems in the small intestine and at the blood-brain barrier [136][137][138][139]. Timing of meals with respect to oral levodopa dosing may also significantly impact levodopa absorption [140].…”

Section: Dietary Considerationsmentioning

confidence: 99%

Clinical implications of gastric complications on levodopa treatment in Parkinson's disease

Pfeiffer

Isaacson

Pahwa

2020

Parkinsonism & Related Disorders

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Disorders of the gastrointestinal (GI) tract are common and distressing nonmotor symptoms of Parkinson's disease (PD) that can adversely affect levodopa absorption and lead to OFF periods, also known as motor fluctuations. Gastroparesis, which is primarily defined as delayed gastric emptying (DGE), and Helicobacter pylori infection, which is present with increased frequency in PD, are among the most common and important GI disorders reported in PD that may impair oral levodopa absorption and increase OFF time. Symptoms of gastroparesis include nausea, vomiting, postprandial bloating, fullness, early satiety, abdominal pain, and weight loss. DGE has been reported in a substantial fraction of individuals with PD. Symptoms of H. pylori infection include gastritis and peptic ulcers. Studies have found that DGE and H. pylori infection are correlated with delayed peak levodopa plasma levels and increased incidence of motor fluctuations. Therapeutic strategies devised to minimize the potential that gastric complications will impair oral levodopa absorption and efficacy in PD patients include treatments that circumvent the GI tract, such as apomorphine injection, levodopa intestinal gel delivery, levodopa inhalation powder, and deep brain stimulation. Other strategies aim at improving gastric emptying in PD patients, primarily including prokinetic agents.

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Protein-Restricted Diets for Ameliorating Motor Fluctuations in Parkinson's Disease

Cited by 48 publications

References 74 publications

Dopaminergic modulation of the exploration/exploitation trade-off in human decision-making

Dopaminergic modulation of the exploration/exploitation trade-off in human decision-making

Dietary Neurotransmitters: A Narrative Review on Current Knowledge

Clinical implications of gastric complications on levodopa treatment in Parkinson's disease

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