The review, published in this week's (February 25) issue of the scientific journal Neuron, illustrates that persistently elevated levels of dopamine in the brain promote the development and maintenance of addictive behaviours.
Addiction is a complex health and societal problem that can destroy lives and damage communities. Brain imaging studies have shown that addiction severely alters brain areas critical to decision-making, learning and memory, and behavior control. In order to learn how to control or manage the disorder, it is necessary to understand the underlying biological mechanisms. Researchers have turned to Parkinson's disease to study addiction, successfully using one disease to learn about another. Although seemingly very different, dopamine plays a role in both disorders and some of the same systems in the brain are affected. Parksinson's disease is often thought as just affecting movement but, it also consists of cognitive, behavioural and mood symptoms, which are now being recognized as a major source of disability.
Dopamine is a neurotransmitter, or chemical messenger in the brain that is involved in brain processes that control movement, emotional response and the ability to experience pleasure, reward and pain. Parkinson's patients lack dopamine and are often treated with dopamine agonists, medication that mimics dopamine action.
"In some instances Parkinson's disease (PD) patients become addicted to their own medication, or develop behavioural addictions such as pathological gambling, compulsive shopping or hypersexuality," says Dr. Alain Dagher, neurologist at the MNI and co-author of the review.
"This is surprising because PD patients typically have a very low incidence of drug abuse and display a personality type that is the opposite of the typical addictive personality. These rare, addictive syndromes, which appear to result from excessive dopaminergic treatment, illustrate the link between dopamine, personality and addiction."
PD patients treated with dopamine agonists had an incidence of pathological gambling as high as 8% compared to less than 1% in the general population. In PD patients who develop addictive disorders, the problems started soon after starting dopaminergic therapy and stopped after treatment was discontinued. It was found that adjusting the dosage and combination of medication resolved the addictive symptoms, while maintaining the same motor benefit.
The phenomenon of addiction induced by dopamine medications can also tell us something about vulnerability to addiction in the general population. Not everyone is equally vulnerable, and it now appears that the propensity to become addicted is in part hereditary. Many of the genes implicated in addiction appear to affect brain levels of dopamine.
Studies show that that dopamine acts in an area of the brain known as the ventral striatum, which receives input from other areas such as the hippocampus and amygdala. It may be through this region that dopamine promotes addictive behaviours.
Understanding brain function that leads to drug addiction may help in the development of drugs to block drug-craving and drug-seeking behaviours in the general population as well as refine disease treatment for Parkinson's patients.
Anita Kar | EurekAlert!
Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
Foods of the future
15.08.2018 | Georg-August-Universität Göttingen
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences