Brain-derived neurotrophic factor (BDNF): what is it?

The neurotrophin BDNF is involved in much of the health of our nervous system.

Brain-derived neurotrophic factor has been shown to be one of the most important neurotrophins in processes such as learning, memory and memory in processes such as learning, memory and thinking.

Inappropriate levels of this substance have also been shown to cause disease, cognitive dysfunction and mood problems.

Below we will go into more detail on exactly what this protein does, some of the disorders in which it has been linked, its mechanism of action and the importance of physical activity for good levels of the factor.

What is brain-derived neurotrophic factor?

Brain-derived neurotrophic factor, better known by its acronym BDNF (brain-derived neurotrophic factor), is a protein, whose gene is located on chromosome 11, which happens to be the most highly expressed neurotrophin in the mammalian brain. is the neurotrophin with the highest expression in the mammalian brain, especially in the cerebral cortex.especially in the cerebral cortex and hippocampus.

These neurotrophins play a very important role during brain development, and continue to exert their action in the plasticity of the nervous system once it has reached maturity.

They have been shown to play an important role in processes such as neurogenesis, maintenance and repair of neuronal function and structural integrity. In fact, Mark Tuszynski, from the University of California, demonstrated that this was one of the factors that, in one of the factors that, in animal models, prevented neuronal death when brain injury occurs..

BDNF function in the nervous system

Neurotrophic factor acts on certain neurons in the central nervous system and also in the peripheral nervous system, helping the neurons in these locations to survive. It also facilitates their growth and differentiation.

This substance is especially active in parts of the central nervous system, namely the cerebral cortex, the hippocampus and the most basal part of the brain.. These areas are involved in cognitive processes such as memory, learning and thinking. It has also been found in places such as the retina, kidneys, motor neurons, skeletal muscle, prostate and even saliva.

Brain-derived neurotrophic factor plays an important role in long-term memory.. Although it is true that a large number of neurons in the mammalian brain are formed during the embryonic stage, parts of the individual's brain, as an adult, have the ability to generate new neurons from neural stem cells. This process is known as neurogenesis. Neurotrophs help to stimulate and control this process, BDNF being the most important.

Mechanism of action

BDNF binds to at least two cell surface receptors, which are able to respond to this growth factor: the Track B (TrkB) and the low affinity receptor for nerve growth factor (LNGFR). Neurotrophic factor modulates the activity of several neurotransmitter receptors, including nicotinic receptors.

1. TrkB

TrkB is encoded by the NTRK2 gene. Activation of the BDNF-TrkB pathway is important for the development of short-term memory and neuronal growth. the development of short-term memory and neuronal growth..

2. LNGFR

The interaction between BDNF and the LNGFR receptor is unclear. Research has pointed to this interaction as being behind the inhibition of neuronal death.

Cognitive abilities

Living in environments with multiple cognitive stimuli, in addition to leading a physically active lifestyle, has been linked to having good overall cognitive function. Cognitive, physical and visual stimulation results in increased neuronal functioning, increasing synaptic communication between neurons, which involves changes in both brain structure and brain chemistry.

Sensory stimuli are first processed by the cortex before reaching the hippocampus. BDNF expression is enhanced in environments rich in cognitive stimuli, which has been attributed to be responsible for better memory and learning ability.This factor has been attributed to be the cause of a better memory and learning capacity. This factor would cause the generation of more synapses (synaptogenesis), dendrites (dendritogenesis) and, as we have already mentioned, greater neurogenesis.

Relationship with pathology

Just as brain-derived neurotrophic factor has been associated with better cognitive ability and being behind processes such as learning, memory and thinking, it was inevitable to observe to what extent this factor may be absent in neurodegenerative diseases and psychiatric disorders. Below we will look at a few of them.

1. Schizophrenia

The fact that BDNF is a crucial substance for the survival of the central and peripheral nervous system, especially in relation to synaptogenesis during and after embryonic development, has led to its association with schizophrenia.

It has been seen that people with the diagnosis show lower amounts of the factor in the dorsolateral prefrontal cortex, an area related to the memory of the brain.an area related to working memory.

2. Depression

High levels of the stress hormone corticosterone have been linked to a reduction in BDNF expression in animal models, implying hippocampal atrophy.

A decrease in the activity of the hippocampus and other limbic structures has been linked to mood problems, especially chronic depression.especially with chronic depression.

On the other hand, it has been shown that the neurotransmitter glutamate, caloric deficit, intellectual stimulation and volunteering, in addition to antidepressants, increase BDNF expression in the brain and reduce depressive symptomatology.

3. Aging

BDNF levels are highly regulated during people's lives, both in the early and later stages of their lives.

As we have already seen, brain-derived neurotrophic factor is shown to be a critical substance in brain development both before and after the prenatal period. As we age, BDNF levels are reduced in brain tissues..

Hippocampal volume is reduced as a result of this phenomenon, suggesting that this reduction in BDNF is implicated in the cognitive problems that are so characteristic of old age.

BDNF and physical exercise

In animal models, especially with rats, it has been observed that moderate physical activity, such as running one kilometer per day, increased BDNF levels in the hippocampus..

These changes in the levels of the factor have been seen to be especially significant in neurons of the dentate gyrus, the hilus and the CA3 region, and are manifested after only a few days. Other regions where changes were found were in the cerebellum, cerebral cortex and lumbar spinal cord.

Research in humans has shown that physical activity helps to maintain and even improve brain plasticity, a characteristic of the hippocampus. Higher functions such as learning or memory benefit from healthy habits such as walking thirty minutes a day, doing any sport or, especially, running.or, especially, jogging. Exercise induces a higher BDNF gene expression.

Bibliographical references:

• Maisonpierre PC, Le Beau MM, Espinosa R, et al. (1991). Human and rat brain-derived neurotrophic factor and neurotrophin-3: gene structures, distributions, and chromosomal localizations. Genomics 10 (3): 558-68.
• Soppet, D; Escandon, E; Maragos, J; et al. (1991). The neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 are ligands for the trkB tyrosine kinase receptor. Cell 65 (5): 895-903.