The journal Nature Communications reports Monday (26) that researchers at the University of Florida Health with Dr. Habibeh Khoshbouei, Pharm D., Ph.D., an Associate Professor of Neuroscience in the UF College of Medicine, discovered underlying mechanics of dopamine transport into and out of brain cells. Development of this research could lead to improvements in treatment efficacy for drug addictions and neurological disorders such as Parkinson’s disease.
Worldwide, there are 10 million people battling Parkinson’s and struggling with stiff limbs, tremors and poor balance.
Dopamine is a vital chemical neurotransmitter produced in the dopaminergic neurons in the ventral tegmental area (VTA) of the midbrain, the substantia nigra pars compacta, and the arcuate nucleus of the hypothalamus. Low levels of dopamine often accompany painful symptoms frequently occurring in patients with Parkinson’s disease.
Released by the brain, dopamine receptors rest on the surface of a cell and act via five different dopamine receptors (D1 thru D5) housed in the Central Nervous System (CNS), the brain, the kidney, and blood vessels. Dopamine receptors can sense external cell molecules and signal a response when triggered by the dopamine chemical.
Khoshbouei calls the dopamine transporter a “powerful, efficient ‘vacuum cleaner’ that helps the brain maintain its normal chemical balance by rapidly drawing dopamine back into the neurons.”
In a normally functioning brain, dopamine is released from the neurons in response to pleasurable or life-sustaining activities, such as eating or sex. When the “vacuum cleaner” works properly, dopamine is eventually swept back into the neurons by the dopamine transporter, returning the brain to a less-stimulated state. Drugs such as cocaine and methamphetamine keep the brain stimulated by preventing neurons from “vacuuming up” excess dopamine.
Dopamine is used in a variety of bodily and brain functions including: movement, memory, pleasurable reward, behavior and cognition, attention, inhibition of prolactin production, sleep, mood, and learning.
The basal ganglia – a part of the brain that regulates movement, depends on a certain amount of dopamine to function well. A dopamine deficiency can spark Parkinson’s disease, a brain disorder that induces shaking and difficulties with coordination and generally focused movement.
If dopamine levels are abnormally high in concentration, other psychiatric disorders such as psychosis and schizophrenia are known to develop.
Dopamine related disorders block the normal transport of dopamine into neurons, much in the way that illicit drugs such as cocaine and methamphetamine affect the brain. A dopamine antagonist is used to treat “conditions resulting from drug abuse through the blocking of dopamine receptors and the inhibiting of the reuptake of dopamine by these receptors.” Antipsychotic medications used to treat conditions like schizophrenia typically act as dopamine antagonists.
In the frontal lobes of the brain, dopamine controls the data tide from other brain centers. Frontal lobe dopamine disorders result in dysfunctions of D1 and D4 receptors, which are responsible for enhanced cognition. Memory functioning, attention abilities, and problem solving skills also damaged.
Researchers found that dopamine movement is affected by changes in electrical properties of the neurons. That, in turn, changes the way dopamine transporters function. Said Khoshbouei, “It’s an important first step. If we know how the dopamine transport system works, then we can start fixing it when it’s broken or malfunctioning.”
While scientists search for the cure to Parkinson’s, dance teachers are leading Parkinson’s patients in dances of creative therapy.
For about the past 15 years, a few thousand participants have taken dance classes through a program called Dance for PD, which began in Brooklyn, spread throughout the country, and is now a therapy used around the world. Dance for PD is easing symptoms and attracting the attention of scientists.