Dopamine is a neurotransmitter with multiple roles in the body.
Dopamine synthesis[edit | edit source]
Dopamine is incapable of crossing the blood-brain barrier so it must be produced in the brain for neuronal activity, or peripherally for peripheral activity.
Peripheral dopamine is produced by the adrenal glands and the gut.
Nervous system[edit | edit source]
Dopamine plays a role in executive function, motor control, motivation, arousal. The largest source of dopamine in the brain is in the substantia nigra and ventral segmental area, both components of the basal ganglia.
Immune system[edit | edit source]
Dopamine has a role in the activity of lymphocytes. It activates native t cells but inhibits the activity of activated t cells. However, dopamine may also induce the release of interleukin-17 in rheumatoid arthritis.
Inflammation may also have a role in dopamine production. A study of Hepatitis C patients found that interferon alpha treatment resulted in significantly increased levels of dihydrobiopterin (BH2) and decreased tetrahydrobiopterin (BH4) as well as reduced conversion of phenylalanine to tyrosine in the cerebrospinal fluid, which are associated with decreased dopamine in the brain.
Fatigue[edit | edit source]
The dopamine imbalance hypothesis of fatigue in neurological disorders states that:
"...fatigue arises [in neurological disease] due to a dopamine imbalance in the central nervous system"
The dopamine hypothesis seeks to explain fatigue in multiple sclerosis, Parkinson's disease, HIV and chronic fatigue syndrome and focuses on the role of central fatigue, which can be physical or mental.
Chronic fatigue syndrome[edit | edit source]
Studies have found lower levels of the dopamine precursor tyrosine and reduced activation in the basal ganglia, the region of the brain with the highest concentration of dopaminergic neurons.
Fibromyalgia[edit | edit source]
Other conditions[edit | edit source]
Parkinson's disease involves the loss of dopaminergic neurons in the midbrain and subsequently reduced dopamine. Schizophrenia, ADHD and restless leg syndrome are also associated with altered dopamine.
In addition to its neurological effects, reduced dopamine may also have immunological effects in these diseases.
Altering dopamine levels[edit | edit source]
See also[edit | edit source]
Learn more[edit | edit source]
References[edit | edit source]
- Mb, Youdim; D, Ben-Shachar; R, Ashkenazi; S, Yehuda (1983). "Brain Iron and Dopamine Receptor Function". Advances in biochemical psychopharmacology. PMID 6138953. Retrieved May 28, 2020.
- Yan, Yiqing; Jiang, Wei; Liu, Lei; Wang, Xiaqiong; Ding, Chen; Tian, Zhigang; Zhou, Rongbin (Jan 2015). "Dopamine Controls Systemic Inflammation through Inhibition of NLRP3 Inflammasome". Cell. 160 (1-2): 62–73. doi:10.1016/j.cell.2014.11.047. ISSN 0092-8674.
- Bordon, Yvonne (Feb 2015). "Dopamine blocks inflammasome activation". Nature Reviews Immunology. 15 (2): 69–69. doi:10.1038/nri3817. ISSN 1474-1741.
- Felger, JC; Li, L; Marvar, PJ; Woolwine, BJ; Harrison, DG; Raison, CL; Miller, AH (Jul 2013). "Tyrosine Metabolism During Interferon-Alpha Administration: Association With Fatigue and CSF Dopamine Concentrations". Brain, behavior, and immunity. PMID 23072726. Retrieved May 28, 2020.
- Dobryakova, Ekaterina; Genova, Helen M.; DeLuca, John; Wylie, Glenn R. (2015). "The Dopamine Imbalance Hypothesis of Fatigue in Multiple Sclerosis and Other Neurological Disorders". Frontiers in Neurology. 6. doi:10.3389/fneur.2015.00052. ISSN 1664-2295. PMC . PMID 25814977.
- Georgiades, Evelina; Behan, Wilhelmina M. H.; Kilduff, Liam P.; Hadjicharalambous, Marios; Mackie, Eileen E.; Wilson, John; Ward, Susan A.; Pitsiladis, Yannis P. (Aug 1, 2003). "Chronic fatigue syndrome: new evidence for a central fatigue disorder". Clinical Science. 105 (2): 213–218. doi:10.1042/CS20020354. ISSN 0143-5221.
- Miller, Andrew H.; Jones, James F.; Drake, Daniel F.; Tian, Hao; Unger, Elizabeth R.; Pagnoni, Giuseppe (May 23, 2014). "Decreased Basal Ganglia Activation in Subjects with Chronic Fatigue Syndrome: Association with Symptoms of Fatigue". PLOS ONE. 9 (5): e98156. doi:10.1371/journal.pone.0098156. ISSN 1932-6203. PMC . PMID 24858857.
- Wood, PB; Glabus, MF; R, Simpson; Jc, Patterson (Jun 2009). "Changes in Gray Matter Density in Fibromyalgia: Correlation With Dopamine Metabolism". The journal of pain : official journal of the American Pain Society. PMID 19398377. Retrieved May 28, 2020.
- Wood, PB; Patterson, JC; Jj, Sunderland; Kh, Tainter; Mf, Glabus; Dl, Lilien (Jan 2007). "Reduced Presynaptic Dopamine Activity in Fibromyalgia Syndrome Demonstrated With Positron Emission Tomography: A Pilot Study". The journal of pain : official journal of the American Pain Society. PMID 17023218. Retrieved May 28, 2020.
- Ciattei, Jennifer. "Causes of Restless Legs Syndrome (RLS) | The Johns Hopkins Center for Restless Legs Syndrome". www.hopkinsmedicine.org. Retrieved May 28, 2020.
- Pacheco, Rodrigo; Contreras, Francisco; Zouali, Moncef (2014). "The Dopaminergic System in Autoimmune Diseases". Frontiers in Immunology. 5. doi:10.3389/fimmu.2014.00117. ISSN 1664-3224.
cofactor - A substance that acts with another substance to bring about certain effects. In biochemistry, a cofactor is a molecule that is necessary for a given biochemical reaction, but is not an enzyme or substrate of the reaction.
enzyme - a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
central nervous system (CNS) - One of the two parts of the human nervous system, the other part being the peripheral nervous system. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system consists of nerves that travel from the central nervous system into the various organs and tissues of the body.
chronic fatigue syndrome (CFS) - A fatigue-based illness. The term CFS was invented invented by the U.S. Centers for Disease Control as an replacement for myalgic encephalomyelitis (ME). Some view CFS as a neurological disease, others use the term for any unexplained long-term fatigue. Sometimes used as a the term as a synonym of myalgic encephalomyelitis, despite the different diagnostic criteria.