Glutamate, a neurotransmitter with multiple (and unknown) functions

Glutamate is one of the most important neurotransmitters in our nervous system. It acts as the true fuel of 80% of our synapses, mediates the formation of memories, the management of attention or the regulation of emotions. In addition, it intervenes in processes as relevant as neuroplasticity, learning or movement.

Many of our readers may know more about glutamate from the food industry (monosodium glutamate) that essential compound that facilitates communication between our nerve cells. It is necessary to differentiate, therefore, dietary glutamate in the form of salt that is used as a food preservative or flavor enhancer, from that amino acid that is synthesized in the central nervous system from glutamine, both in presynaptic neurons and in glial cells.

Under normal conditions, Endogenous glutamate is one of the most abundant amino acids in our body. We produce it thanks to the proteins we consume and it is the main excitatory neurotransmitter. At the same time, as neuroscientists explain to us, we are dealing with that element whose main purpose is to offer energy to the brain.

On the other hand, and in reference to exogenous glutamate, it should be said that the idea that it can be dangerous for our brain health is well known. Now, as explained to us in a study carried out at the Nutrition Center of the Faculty of Medicine of the University of Pittsburgh and published in the The Journal of Nutrition, There is no evidence of obvious neurological damage as a result of dietary glutamate consumption.. However, let’s dig deeper.

Glutamate and GABA: the two faces of nervous activation

Just as glutamate acts as an “on switch” in nerve pathways, GABA inhibits this activity. Therefore, for proper functioning of the CNS, a balance between these two neurotransmitters is necessary.

Receivers

The effect of glutamate occurs at a neurochemical level. Thus, to function it must join other molecules, as if they were a lock and its key. There are 2 types of receptors for this molecule:

Receivers associated with channels ionic: Glutamate makes way for certain ions by binding to its receptor, modifying the electrical charge of the cell and sending the impulse to the next. There are 3 different types; the NMDA, the AMPA and the Kainado.G protein-coupled receptors: Upon binding to the receptor, glutamate activates and deactivates molecules within cells, causing a biochemical cascade that transmits the electrical impulse.

glutamate synthesis

This molecule is synthesized within the complex Krebs cycle, the metabolic pathway that produces cellular respiration in the mitochondria. The precursor of glutamate is alpha-ketoglutarate, in addition to glutamine. In the case of the latter, it is released by astrocytes, reuptaken by neurons and converted into glutamate.

Glutamate: an amino acid with very different functions

Glutamate is the mediator of a healthy brain. Not us, but an interesting study carried out at the Institute of Basic Medical Sciences, University of Oslo. In fact, it is striking how in recent years new and fascinating discoveries have been made about this amino acid involved in multiple metabolic tasks.

Let’s see, therefore, what its main functions are. You have them in the following sections.

Main mediator of excitatory signals

The central nervous system (CNS) is made up of neurons and glial cells (the most abundant). Thanks to the synaptic connections they establish between them, we can carry out functions as basic as cognitive, sensory, motor, etc. processes. Well, in this complex process, it is glutamate itself that acts as a chemical messenger (neurotransmitter) between cells and neurons after an electrical stimulus.

Thus, and because glutamate is the main mediator of excitatory signals, It is necessary that your concentrations are always correct so that you can carry out this task. A deficit would make that communication difficult (we would have no energy, so to speak). An excess, on the other hand, would have a very harmful effect on our brain. It would lead to the appearance of ischemia, cerebrovascular accidents, hypoxia, epileptic seizures, etc.

Glutamate facilitates our brain development

He glutamate is so important for fetal brain development as well as for neuroplasticity during childhood and youth development, and also in adulthood. Thanks to this amino acid, neuronal differentiation, migration and the creation of new connections are carried out, and in essence, the good condition of the brain.

Now, it is also well known that in conditions as serious as Huntington’s disease, Parkinson’s disease and Alzheimer’s disease, glutamate contributes to cell death itself. Alteration in their concentrations and functions can also give rise to this series of chronic neurodegenerative disorders.

Glutamate and glucose metabolism

In a study carried out at the Faculty of Medicine of Kobe University, Japan and published in the journal Cell Reports something very considerable was revealed. It has been discovered that Glutamate has a direct relationship with the pancreas, as it modulates the activity of pancreatic beta cells to promote insulin production.

In this way, the importance of this amino acid to give us “energy” and above all, to optimize brain functions is revealed once again. We must remember that the brain cannot extract its energy from lipids, therefore, it needs glucose to carry out its main functions, a need that is covered and satisfied by that very relevant neurotransmitter: glutamate.

Glutamate neurotoxicity

As we have explained, We do not have evidence to support the idea that the consumption of monosodium glutamate generates neuronal alterations.. Now, it doesn’t hurt to keep some control over its intake, since it is known to be addictive. On the other hand, a balanced diet will reduce the probability of harm from its consumption.

On the other hand, Glutamate-associated neurotoxicity does not always originate from exogenous factors. The main cause would be different pathological conditions, alterations of ionotropic receptors, sometimes genetic or not yet known problems that activate hyperexcitability associated with glutamate, neurotoxicity, and consequent neuronal death.

Thus, it is known, for example, that an excess of this amino acid can generate, as we have pointed out, ischemia, problems in the brain development of fetuses, memory problems, epilepsy, muscle pain, etc. Nevertheless, It should be said that there is a treatment for this and that there are drugs that mediate the regulation of glutamate concentrations..

To conclude, it is worth noting that studies and research continue today around this very interesting component. This excitatory neurotransmitter that facilitates almost any function of our brain.

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