Dopaminergic neurons: characteristics and functions - psychology - 2023
- What are dopaminergic neurons?
- Dopamine as a product of these neurons
- How is dopamine transported? The dopamine pathways
- 1. Mesolimbic pathway
- 2. Mesocortical route
- 3. Nigrostriatal pathway
- 4. Tuberoinfundibular route
- What functions do these neurons fulfill?
- 1. Regulate the feeling of pleasure and motivation
- 2. They mediate cognitive processes
- 3. They enable movement
The experimentation of sensations of well-being and pleasure, as well as the correct functioning of systems such as the motor apparatus and cognitive functions is possible thanks to the production and release of a neurotransmitter substance known as dopamine.
Those in charge of these tasks of manufacturing and transmission of this neurotransmitter so essential in human functioning are dopaminergic neurons, which we will talk about throughout this article. In it, we will describe their main characteristics, as well as their functions and the pathways they use to travel through the nervous system.
- Related article: "Types of neurons: characteristics and functions"
What are dopaminergic neurons?
Dopaminergic neurons are defined as that set of brain cells that inhabit the nervous system and whose mission is to produce the neurotransmitter known as dopamine, as well as to transmit it to other cells of the nervous system.
The release of dopamine enables the activation of certain brain structures and areas that enable functions related to movement and motivation, as well as a large number of higher cognitive functions.
This release and transmission of dopamine throughout the various structures of the nervous system is possible thanks to dopaminergic pathways. These pathways consist of a series of interconnected neuron pathways through which dopamine travels.
Said neurotransmitter is produced in the neuronal cytoplasm, within the neuron soma, to be transmitted later through the axons of this, which create projections towards the different synapse sites.
As a consequence, any type of injury, condition or disease that causes the degeneration of dopaminergic cells will result in the appearance of all kinds of diseases in which the person experiences a gradual worsening in their brain functions. Among these conditions we find neurodegenerative diseases such as Parkinson's or others such as schizophrenia.
- You may be interested: "Types of neurotransmitters: functions and classification"
Dopamine as a product of these neurons
As mentioned above, dopamine is the neurotransmitter produced by these dopaminergic neurons. This substance belonging to the group of catecholamines is found throughout the entire central nervous system, specifically in the intersynaptic space of the brain.
Dopamine's mission is to activate different types of dopamine receptors, which harbor specific receptors for this neurotransmitter. Thanks to these receptors, dopamine is released and reuptained along all dopaminergic pathways.
Despite the fact that this type of dopaminergic neurons can be located in a large number of structures of the nervous system, they tend to occur to a greater extent in the substantia nigra, named for the large amount of melatonin it contains and which gives it its color. characteristic, as in the hypothalamus.
How is dopamine transported? The dopamine pathways
The dopamine system, and therefore its neurons, are arranged in a series of pathways known as dopamine pathways. These are distributed throughout different areas of the nervous system, within which they fulfill a certain function.
Although there are eight different dopaminergic pathways, only four of them acquire greater relevance in the development of dopaminergic functions. These four pathways that make up part of the system are: the mesolimbic pathway, the mesocortical pathway, the nigrostriatal pathway, and the tuberoinfundibular pathway.
1. Mesolimbic pathway
Thanks to this pathway, dopamine travels from the ventral tegmental area to the nucleus accumbens. It is located in the midbrain, also known as the midbrain, and its malfunction is related to disorders such as schizophrenia.
- You may be interested: "Mesolimbic pathway (brain): anatomy and functions"
2. Mesocortical route
In this second pathway, the neurotransmitter is transported from the ventral tegmental area to the frontal cortex. Like the mesolimbic pathway, alteration of the mesocortical pathway is also related to schizophrenia. However, it tends to have a greater impact on the cognitive processes of this.
3. Nigrostriatal pathway
As its name suggests, the nigrostriatal pathway releases dopamine from the substantia nigra to the striatum and its functions are associated with motor control. An alteration in this pathway can cause disorders such as Parkinson's disease or different types of chorea.
4. Tuberoinfundibular route
This last pathway transfers dopamine from the hypothalamus to the pituitary, exerting its influence on some hormones such as prolactin. As a consequence of some alteration in its functioning, prolactin levels in the blood may increase, causing a condition known as hyperprolactinemia.
What functions do these neurons fulfill?
At the beginning of the article, it was already mentioned that dopamine, and therefore dopaminergic neurons, have an essential role in numerous functions of the nervous system. However, there are a series of actions or processes in which dopaminergic neurons are particularly relevant.
1. Regulate the feeling of pleasure and motivation
If there is one thing for which dopaminergic neurons have gained special fame, it is for their involvement in the processes of pleasure and motivation.
Thanks to the release of dopamine by neurons in the ventral tegmental areas and in areas of the amygdala, the lateral septal area, the neocortex or olfactory nuclei and accumbens, the brain generates the sensations of pleasure and reward.
These neurochemical reactions occur in rewarding or gratifying situations such as sexual behaviors, addiction processes or eating.
2. They mediate cognitive processes
In this case, dopaminergic neurons located in the frontal lobes of the brain play a special role in the development and proper functioning of cognitive processes such as memory, attention, and the ability to solve problems.
In the frontal lobes, dopamine release mediates the flow of information from other areas of the nervous system. As a consequence, the injury or degeneration of these brain areas leads to the appearance of the aforementioned neurodegenerative diseases, such as Parkinson's disease, which cause cognitive deterioration in the patient, as well as alterations and motor problems.
3. They enable movement
Finally, and although dopaminergic neurons are involved in many other processes, these they have a special role in the correct development of movements, as well as allow the person to perform all kinds of fine and controlled movements.
This explains the appearance of the motor symptoms so characteristic of Parkinson's disease, which are due to a deficit in dopamine production due to neurodegeneration.