Purkinje neurons, the enigmatic cells of the cerebellum and heart

Under a microscope, Purkinje neurons look like little Christmas trees. Neuroscience experts define them as a challenge and a mystery. It is known, for example, that they are in the cerebellum and also in our heart, and that, according to various very recent studies, they could have some type of link with the appearance of autism spectrum disorder (ASD).

The neurological universe is almost as fascinating as the cosmos itself. Seen through a lens, this type of cell not only attracts attention due to its striking shape and large size. Purkinje neurons, in turn, receive up to ten times more connections than any other type of neuron.

Scientists have been looking at this type of structure for years because, unlike other inhibitory neurons, They also have the ability to “turn off” the functioning of other cells external to the cerebellum.. Its electrophysiological activity is so particular that it opens the door to the possibility of developing new treatments and approaches for various conditions.

However, it takes time. Thus, universities, such as Tokyo, have been carrying out studies and observations at the laboratory level with zebrafish for years.trying to understand many of its functions, as well as its possible involvement in the development of certain neurological disorders.

Let us therefore try to learn more about the interesting Purkinje neurons.

Purkinje neurons: what they are and where they are

Purkinje neurons are a type of GABAaergic brain cell (that is, they have inhibitory functions). There are about 30 million of this type of neurons in the cerebellum and the same number in the heart muscle. Thus, and thanks to the large number of Purkinje fibers existing in the cardiac muscle, the electrical impulse is also produced and transmitted.

Its discoverer was Jan Evangelista Purkyně. He was a neurologist at the University of Breslau, Prussia, who in 1832 was able to observe them for the first time using a type of achromatic microscope. Five years later, he would present his discovery to the scientific community in ancient Bohemia, now the Czech Republic.

Years later, Camillo Golgi, from the University of Pavia, in Italy, examined Purkinje cells by staining them with silver nitrate, trying to understand a little more about how they function. Santiago Ramón y Cajal, from the University of Barcelona, ​​would also carry out his own research.. It was in 1906 when both scientists received the Nobel Prize in Medicine for their contribution to understanding the structure of the nervous system.

As they are?

As we have already noted, Purkinje cells are inhibitory neurons. We also know that They are very large and receive a large number of connections. Dr. Thomas Launey, director of the molecular research unit at the Riken Institute in Japan, is one of the leading experts on these brain structures.

As he himself explains to us in different works, they have the shape of a tree, with highly branched dendrites and a single axon from which to send electrical impulses.Each cell body has a diameter of about eighty microns. Likewise, it has a very intense potential to inhibit the excitatory neurons of the spinal cord. One of its main characteristics is to be able to “turn off” other neurons that are outside the cortex of the cerebellum. On the other hand, It should be noted that there are two types of Purkinje neurons: mossy cells (which come from the brainstem) and climbing cells (which ascend from the medulla oblongata).

Purkinje neurons and their inhibitory functions

Purkinje cells are involved in motor processes and also in learning. We cannot ignore the large number of discoveries that have been made in recent years about the functions of the cerebellum, where these cells will undoubtedly have key importance.

Most Purkinje cells release a neurotransmitter called GABA (gamma-aminobutyric acid), which exerts inhibitory actions on other neurons. In this way, nervous impulses are reduced in order to regulate and coordinate our motor movements.This electrophysiological regulation is achieved in two ways. It can do so through its simple dendrites (or spikes), which exert electrical activity ranging from 17 to 150 Hz. Likewise, it can also activate a more intense type of electrical impulse that would have a potential between 1 and 3 Hz.Finally, it is interesting to know that also They facilitate concentration during learning processes.

Purkinje cells and autism

Magazine Molecular Psychiatry published an interesting study carried out at Harvard Medical University in early 2018. According to this work, a dysfunction of the Purkinje cells in the cerebellum could mediate the appearance of autism spectrum disorder (ASD). It is one more hypothesis that has been around for very recently.

The origin of this alteration would be genetic and would be called tuberous sclerosis (TSC). It has been seen, for example, that many patients with autism have a very low level of this type of neurons. This leads to problems regulating behavior, movements, the constant hyperstimulation that these people feel, as well as the resulting social deficits.

Currently, work is being done on the production of Purkinje neurons from stem cells. A type of protein is also being designed that could help children reactivate the functionality and production of this type of structure, which is so important and decisive at the same time. We will therefore be awaiting more data and information on a topic that, without a doubt, opens up multiple possibilities for us.

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