Experimentation with feelings of well-being and pleasure, as well as the proper functioning of systems such as the motor apparatus and cognitive functions is possible through the production and release of a neurotransmitter called dopamine.
Those responsible for these tasks of manufacturing and transmitting this neurotransmitter so essential to human functioning are dopaminergic neurons, which we’ll talk about throughout this article. We will describe their main characteristics, as well as their functions and the pathways they take to pass through the nervous system.
What are dopaminergic neurons?
Dopaminergic neurons are defined as the set of brain cells that live in the nervous system and the mission is to produce the neurotransmitter called dopamine, as well as to transmit it to other cells of the nervous system.
The release of dopamine allows the activation of certain structures and areas of the brain that allow functions related to movement and motivation, as well as a large number of higher cognitive functions.
This release and transmission of dopamine along the various structures of the nervous system is possible thanks to the dopaminergic pathways. These pathways consist of a series of interconnected neural pathways through which dopamine travels.
This neurotransmitter is produced in the neuronal cytoplasm, within the soma of the neuron, to be transmitted later by its axons, Which create projections to the different synapse sites.
As a result, any kind of injury, condition or disease that causes degeneration of dopamine cells will lead to the onset of all kinds of diseases in which the person will experience progressive worsening of their brain functions. These conditions include neurodegenerative diseases such as Parkinson’s disease or others such as schizophrenia.
Dopamine as a product of these neurons
As already mentioned above, dopamine is the neurotransmitter produced by these dopaminergic neurons. This substance belonging to the group of catecholamines is found throughout the central nervous system, more precisely in the intersynaptic space of the brain.
The mission of dopamine is to activate different types of dopamine receptors, Which house specific receptors for this neurotransmitter. Thanks to these receptors, dopamine is released and collected along all dopaminergic pathways.
Although this type of dopaminergic neurons can be localized in a large number of structures in the nervous system, they tend to occur to a greater extent in substantia nigra, so called due to the large amount of melatonin it contains. and of which it brings its characteristic color, as in the hypothalamus.
How is dopamine transported? Dopaminergic pathways
The dopaminergic system, and therefore its neurons, are ordered into a number of pathways known as dopaminergic pathways. these they are distributed along different areas of the nervous system, Within which they perform a certain function.
Although there are eight different dopaminergic pathways, only four of them acquire more relevance in the development of dopaminergic functions. These four pathways which constitute part of the system are: the mesolimbic pathway, the mesocortical pathway, the nigroestriatal pathway and the tuberoinfundibular pathway.
1. Mesolimbic route
Through this pathway, dopamine moves from the ventral tegmental area to the nucleus accumbens. It is located in the midbrain, also known as the midbrain, and dysfunction of this has been linked to disorders such as schizophrenia.
2. Mesocortical route
In this second pathway, the neurotransmitter is transported from the ventral tegmental area to the frontal cortex. Like the mesolimbic tract, alteration of the mesocortical tract it is also linked to schizophrenia. However, it tends to have a greater impact on cognitive processes than this.
3. Your black striatal
As the name suggests, the black striatal pathway releases dopamine from the substantia nigra to the corpus striatum and its functions are associated with motor control. Impairment of this pathway can cause disorders such as Parkinson’s disease or different types of chorea.
4. Your tuberoinfundibularis
This last path transfers dopamine from the hypothalamus to the pituitary gland, exerting its influence on certain hormones such as prolactin. Due to certain changes in their functioning, blood levels of prolactin may increase, causing a condition known as hyperprolactinemia.
What functions do these neurons perform?
At the beginning of the article, it is already mentioned that dopamine, and therefore dopaminergic neurons, play an essential role in many functions of the nervous system. However, there are a number of actions or processes in which dopaminergic neurons are of particular importance.
1. They regulate the feeling of pleasure and motivation
If there is one thing for which dopaminergic neurons have gained a special reputation, it is their involvement in the processes of pleasure and motivation.
Thanks to the release of dopamine by neurons in the ventral tegmental areas and in the areas of the amygdala, lateral septal area, neocortex or olfactory nuclei lol and accumbens, the brain generates sensations of pleasure and reward. .
These neurochemical reactions occur in reward or gratification situations such as sexual behavior, addiction process or diet.
2. They intervene in 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, the release of dopamine mediates the flow of information from other areas of the nervous system. Consequently, the lesion or degeneration of these areas of the brain leads to the appearance of the aforementioned neurodegenerative diseases, such as Parkinson’s disease, which cause cognitive disorders in the patient, as well as alterations and motor problems.
3. They allow movement
Finally, although dopaminergic neurons are involved in many other processes, these they play a special role in the proper development of movements, In addition to allowing 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.