This molecule is key to our well-being. We explain its functions in this article!
Dopamine is a molecule with various functions in our body. One of its best-known functions is as a regulator of the reward system of our brain , which gives us pleasure when carrying out activities that are good for our survival, although it is also related to drug addiction.
In this article we will explain to you what exactly dopamine is and what some of its known functions are so far.
Neurotransmitters: what are they?
Neurotransmitters are molecules that affect the nervous system . They are secreted by cells of the nervous system, through synapses, for communication and biochemical regulation of neurons.
Synapses are spaces between neurons, where communication between these cells occurs. Neurotransmitter communication occurs when a neuron releases these molecules into the synaptic cleft, where they will interact with receptors on adjacent neurons.
This type of communication between neurons is different from electrical signals (when neurons exchange ions with positive or negative charges), but both processes are closely related and are necessary for the proper functioning of the nervous system.
What is dopamine?
Dopamine is a molecule of the catecholamine family, like adrenaline, with a neurotransmitter function when it interacts with the nervous system and with a hormonal function when it interacts with other parts of the body that have receptors for dopamine, such as the kidneys. , where it will have vasodilator and diuretic functions.
There are five types of dopamine receptors. D1, D2, D3, D4 and D5. These are distributed throughout the body. In the brain we would mainly find the D1 and D2 receptors.
Dopamine is generated primarily by dopaminergic neurons, which are found mostly in the hypothalamus, olfactory bulb, and some parts of the midbrain.
Dopamine plays a central role in processes such as:
- The reward system
- lactation
- The emotions
- The dream
- The learning
- Control of nausea and vomiting
- The processing of pain
In addition to having an important role in the regulation of cognition (thinking) and movement . Having a wide variety of functions, the disorders in which dopamine will be related will be diverse as well.
dopaminergic pathways
We will find four main functional axes of dopamine:
1. The nigrostriatal pathway
In this pathway, dopamine plays an important role in controlling motor activity and learning new motor skills. The degradation of this pathway is related to Parkinson’s disease, which is characterized by involuntary movements.
2. The mesolimbic pathway
In this pathway instead, dopamine has functions in the emotional and reward systems. This pathway is the one that mediates, through dopamine, pleasure. It is the pathway that stimulates us to do pleasurable activities, such as eating or sex . It is also the system that is related to drug addiction processes.
3. The mesocortical pathway
Mesocortical dopamine is responsible for regulating cognition and emotional behavior. Dopamine in the prefrontal cortex helps improve memory and attention. But the action of dopamine in this system is very delicate, since higher or lower amounts than usual worsen memory processes.
4. The tuberoinfundibular pathway
It is a pathway that connects the hypothalamus with the pituitary gland, here the role of dopamine is to stop lactation by preventing the formation of prolactin, the hormone responsible for this process.
Dopamine related disorders
Dopamine levels are important for many of our vital functions and their alteration, or the alteration of the pathways by which they act, can cause us serious illnesses or even psychiatric disorders such as social anxiety and depression . Here we present four serious disorders that seem to be related to dopamine and its functions as a neurotransmitter.
1. Parkinson’s disease
It is the most common motor neurodegenerative disease and is caused by the loss of dopaminergic neurons in the nigrostriatal pathway, affecting the function of the basal ganglia, and the appearance of so-called Lewis bodies in the intraneuronal space. It normally affects individuals over 60 years of age, with an incidence of between 150 and 200 cases per 100,000 inhabitants .
- You may be interested in: “Parkinson’s: what is it, types, symptoms and causes”
2. Huntington’s disease
Huntington’s disease is an autosomal dominant genetic disease, caused by the elongation of a part of the gene responsible for the disease, which under normal conditions is responsible for secreting a protein called huntingtin, in reference to the disease. It causes aggressive motor and cognitive impairment, which worsens drastically over the years .
Those who present it have lower levels of interaction between dopamine and D1 and D2 receptors than those of a person not affected by Huntington’s disease.
3. Schizophrenia
A severe mental illness that affects 1% of the population, with more severity in men , appearing especially during adolescence or early adulthood and rarely after 50 years of age.
Although the mechanism of action of schizophrenia is not known with certainty, there is scientific evidence to imply that normal dopamine function is impaired in schizophrenic patients.
4. ADHD (Attention Deficit Hyperactivity Disorder)
One of the most prevalent psychiatric disorders today, especially when we talk about those that affect children. It is estimated that 5% of the world’s child population and 2.5% of the adult population suffer from ADHD . The locomotor hyperactivity associated with this disorder is related to dopaminergic dysfunction.
In addition, some of the genes usually linked to ADHD are key to the functioning of dopamine.
Bibliographic references
- Klein, MO et al. (2018). Dopamine: Functions, Signaling, and Association with Neurological Diseases. Cellular and Molecular Neurobiology.
- Ayano, G. (2016) Dopamine: Receptors, Functions, Synthesis, Pathways, Locations and Mental Disorders: Review of Literatures. J Ment Disord Treat
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.