GABA (neurotransmitter): what is it and what role does it play in the brain?

Gamma-aminobutyric acid and its main functions within the central nervous system.

The GABA (gamma-aminobutyric acid) is a neurotransmitter widely distributed in the neurons of the cerebral cortex. What does this mean? Well, GABA is a type of substance that is used by the neurons of the nervous system when communicating with each other through spaces (called synaptic spaces) through which they connect with each other.

However, GABA is only one of many types of neurotransmitters of the many that act in the brain. That is why it performs some functions that other neurotransmitters do not. Its function is to be an inhibitory neurotransmitter.

GABA, the inhibitory neurotransmitter

GABA is a neurotransmitter (like serotonin or dopamine) and, therefore, it is an inhibitory neurotransmitter, sends chemical messages through the brain and nervous system.. In other words, it participates in the communication between neurons.

GABA's role is to inhibit or reduce neuronal activity, and it plays an important role in behavior, cognition and the body's response to stress. Research suggests that GABA helps control fear and anxiety when neurons become overexcited.

On the other hand, low levels of this neurotransmitter are associated with anxiety disorders, sleep problems, depression and schizophrenia. It has also been found that young neurons are more excitable than older neurons, and this is due to the function that GABA exerts on the latter.

GABA contributes to motor control, vision or regulates anxiety, among other cortical functions. There are various drugs that increase GABA levels in the brain and are used to treat epilepsy, Huntington's disease or to calm anxiety (e.g. benzodiazepines).

It should be noted, however, that little is still little is known about the functions and processes in which GABA is involved, and it is therefore hasty to assume that its usefulness is simply that which I have described. In addition, this neurotransmitter intervenes to a greater or lesser extent in other dynamics of communication between neurons in which other neurotransmitters play a more relevant role.

The relation of GABA to fear and anxiety

GABA was discovered in 1950 by Eugene Roberts and J. Awapara, and since then several studies have been carried out to better understand its relationship with anxiety disorders.

In recent decades, research on GABA and benzodiazepines has been numerous, mainly in search of treatments for pathological alterations of fear and anxiety.The main purpose of these studies has been to find treatments for the pathological alterations of fear and anxiety. These studies have concluded that GABA is involved in these emotions, but it does not seem that its role is other than that of inhibitory modulator of other neurotransmitter systems such as noradrenaline.

In addition, other studies have also provided interesting conclusions as to how the effect of this neurotransmitter is able to reduce the effects of stress in individuals. In an experiment published in the Journal of Neuroscience it was shown that when individuals perform regular physical exercise, the level of GABA neurons increases in the brain, which affects the ventral hippocampus, a brain region linked to the regulation of stress and anxiety. Another study, this time conducted jointly by Boston University and the University of Utah, found that there is also an increase of this neurotransmitter in yoga practitioners.

To learn more about the psychological benefits of physical exercise and yoga you can read our articles:

• The 10 psychological benefits of practicing physical exercise
• The 6 psychological benefits of yoga
• 10 benefits of yoga for athletes (according to science)

How is GABA synthesized?

GABA is synthesized from the decarboxylation of glutamate by the enzyme glutamate decarboxylase (GAD), a process that occurs in GABAergic neurons in the cerebellum, basal ganglia and many areas of the cerebral cortex, also in the spinal cord. If the synthesis of this neurotransmitter is inhibited, convulsive seizures occur.

GABA receptors

GABA receptors are probably the most numerous in the mammalian nervous system. It is estimated that are present in at least 30-40% of nerve cells in the human brain..

There are three types of receptors for GABA: GABA-A, GABA-B and GABA-C. The latter is considered a subtype of the GABA-A receptor, and is also called GABA-A rho.

The GABA-A receptor, the best known

The ionotropic GABA-A receptor, which is located on the plasma membrane of the post-synaptic terminal, is the one associated with benzodiazepines such as Diazepam (better known as Valium), barbiturates or alcohol. It is the best known receptor and is composed of five polypeptide subunits.α, β, γ, δ, ε, each with different functions.

If you want to know more about this receptor, the following video explains the structure and function of the GABA-A receptor:

The GABA-B receptor is metabotropic, and is found in the plasma membrane of pre- and post-synaptic terminals. The GABA C receptor, like GABA-A, is ionotropic.

Ionotropic and metabotropic receptors

Ionotropic receptors are so named because they are coupled to an ion channel, and when ligand binds to them the channel opens and an ion enters or exits through the channel. In the case of the GABA-A receptor, chlorine (Cl-) enters, which produces the inhibitory response. Its effect is rapid, as the channel only has to be opened to produce the action.

In contrast, metabotropic receptors, such as GABA-B, are slower receptors and are coupled to G proteins, which, specifically in the case of this receptor, lead to the activation of potassium (K+) channels for depolarization of the cell.

Other neurotransmitters and their functions

In addition to GABA, in Psychology and Mind We have already discussed other neurotransmitters and how they function within the brain. Among them serotonin, also known as the happiness hormone, and dopamine, a chemical related to pleasurable behaviors and reinforcement. So don't miss the following articles:

• Serotonin: discover the effects of this hormone on your body and mind.
• Dopamine: 7 essential functions of this neurotransmitter.

Bibliographical references:

• Bloom, F. 1994. Psychopharmacology. The fourth generation of progress. Raven Press.