Dopaminergic neurons: characteristics and functions

This type of nerve cells are involved in many brain processes.

The experience of feelings 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.

In charge of these tasks of production and transmission of this neurotransmitter so essential in human functioning are dopaminergic neurons, which will be discussed in 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.

What are dopaminergic neurons?

Dopaminergic neurons are defined as the group 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 makes possible the activation of certain structures and areas of the brain that enable movement-related functions. that enable functions related to movement and motivation, as well as a large number of higher cognitive functions.

This release and transmission of dopamine along the different structures of the nervous system is possible thanks to the dopaminergic pathways. These pathways consist of a series of interconnected neuronal pathways through which dopamine travels.

This neurotransmitter is produced in the neuronal cytoplasm, within the soma of the neuron, to be subsequently transmitted through the axons of the neuron.which create projections to 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 of his or her brain functions. Among these conditions we find neurodegenerative diseases such as Parkinson's or others such as schizophrenia.

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 central nervous system, specifically in the intersynaptic space of the brain.

The task of dopamine is to activate the different types of dopamine receptors, which harbor specific receptors for this neurotransmitter.which harbor specific receptors for this neurotransmitter. Thanks to these receptors, dopamine is released and reuptaken along all dopaminergic pathways.

Although 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, so called because of the large amount of melatonin it contains and which gives it its characteristic color, as well as in the hypothalamus.

How is dopamine transported? The dopaminergic pathways

The dopaminergic system, and therefore its neurons, are arranged in a series of pathways known as dopaminergic pathways. These are distributed along different areas of the nervous system, within which they perform awithin which they fulfill a specific 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 form 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 a malfunction of this pathway is related to disorders such as schizophrenia.

Mesocortical pathway

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. is also related to schizophrenia.. However, it tends to have a greater impact on the cognitive processes of the latter.

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 pathway

This last pathway carries dopamine from the hypothalamus to the pituitary gland, exerting its influence on certain hormones such as prolactin.. As a consequence of some alteration in its functioning, prolactin levels in Blood can increase causing a condition known as hyperprolactinemia.

What are the functions of these neurons?

At the beginning of the article it was already mentioned that dopamine, and therefore dopaminergic neurons, play 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. They regulate the sensation of pleasure and motivation.

If there is one thing for which dopaminergic neurons have gained special fame, it is their involvement in the processes of pleasure and motivation.

Thanks to the release of dopamine by neurons in the ventral tegmental area and in areas of the amygdala, the lateral septal area, the neocortex or the olfactory and accumbens nuclei, the brain generates the sensations of pleasure and reward.

These neurochemical reactions occur in situations of reward or gratification, such as sexual behaviors, addictive sexual behaviors, addiction processes or in feeding..

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 problem solving. cognitive processes such as memory, attention and problem-solving abilities..

In the frontal lobes, dopamine release mediates the flow of information from other areas of the nervous system. As a consequence, the lesion 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 make movement possible

Finally, and although dopaminergic neurons are involved in many other processes, they have a special role in the proper have a special role in the correct development of movements., así como posibilitan que la persona pueda realizar todo tipo de movimientos finos y controlados.

Esto explica la aparición de los síntomas motores tan característicos de la enfermedad de Parkinson, los cuales son debidos a un déficit en la producción de dopamina a causa de la neurodegeneración.