Gamma-aminobutyric acid and its main functions within the central nervous system.
The GABA ( gamma-aminobutyric acid ) is a neurotransmitter widely distributed in neurons of the cerebral cortex. What does this mean? Well, GABA is a type of substance that is used by neurons of the nervous system when it comes to communicating with each other through spaces (called synaptic spaces) by which they connect with each other.
Now, GABA is just 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 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 are over-excited.
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 old ones, and this is due to the role that GABA exerts on the latter.
GABA Contributes to motor control, vision or regulates anxiety, among other cortical functions. There are different drugs that increase GABA levels in the brain and are used to treat epilepsy, Huntington’s disease, or to calm anxiety (for example, benzodiazepines).
It must be borne in mind, however, that little is still known about the functions and processes in which GABA intervenes, and therefore it is 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 communication dynamics between neurons in which other neurotransmitters play a more relevant role.
GABA’s relationship to fear and anxiety
GABA was discovered in 1950 by Eugene Roberts and J. Awapara, and since then various studies have been carried out to better understand its relationship with anxiety disorders.
In recent decades, research on GABA and benzodiazepines has been numerous, basically to seek treatments against the pathological disorders 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 an inhibitory modulator of other neurotransmission systems such as norepinephrine.
In addition, other studies have also provided interesting conclusions regarding how the effect of this neurotransmitter is capable of reducing the effects of stress in individuals. In an experiment published in the Journal of Neuroscience it was shown that when individuals engage in regular physical exercise, the level of GABA neurons increases in the brain, affecting the ventral hippocampus, a region of the brain linked to the regulation of stress and anxiety. Another study, this time carried out jointly by Boston University and the University of Utah, found that there is also an increase in 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 glutamate decarboxylation thanks to the action of 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, seizures occur.
GABA receptors are probably the most numerous in the mammalian nervous system. It is estimated that they 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 plasmatic membrane of the postsynaptic terminal, is the one that is related to benzodiazepines such as Diazepam (better known as Valium), barbiturates or alcohol. It is the best known receptor and it is composed of five polypeptide subunits : α, β, γ, δ, ε, each with different functions.
If you want to know more about this receiver, the following video explains the structure and operation of the GABA-A receptor:
The GABA-B receptor is metabotropic, and it is found on the plasma membrane of the pre- and postsynaptic terminals. The GABA C receptor, like GABA-A, is ionotropic.
Ionotropic and metabotropic receptors
Ionotropic receptors receive this name because they are coupled to an ion channel, which when the ligand binds to them the channel opens and an ion enters or leaves the channel. In the case of the GABA-A receptor, chlorine (Cl-) enters, which produces the inhibitory response. Its effect is fast because you just have to open the channel 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 the depolarization of the cell. .
Other neurotransmitters and their functions
In addition to GABA, in Psychology and Mind we have already talked about other neurotransmitters and their functioning within the brain. Among them serotonin, also known as the happiness hormone, and dopamine, a chemical related to pleasant 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
Bloom, F. 1994. Psychopharmacology. The fourth generation of progress. Raven Press.