Also known as gamma-aminobutyric acid, it is a CNS-inhibiting substance.
Neurotransmitters exert different functions in the brain. Some are excitatory, and others inhibitory (depressants).
The main depressant neurotransmitter is GABA (gamma-aminobutyric acid) , a substance that facilitates states of relaxation and protects us from anxiety.
In this article we will learn about its characteristics, functions, mechanism of action, agonist substances, disorders in which it is involved and other important aspects of it. In addition, we will know how GABA levels can be increased both naturally and artificially.
GABA: what is it and how does it work?
Gamma-aminobutyric acid, also known as GABA, is a neurotransmitter widely distributed throughout the brain (it is an amino acid) . It is considered the main inhibitory substance of the Central Nervous System (CNS) and exerts depressant functions on it.
GABA is responsible for regulating the excitability of the brain ; It does this by inhibiting the firing of neurons. In a way, it deactivates excitatory hormones, such as adrenaline.
This provides a feeling of relaxation and peace . For this reason, as we will see later, some types of anxiolytics (drugs that reduce anxiety) act on GABA, enhancing its effect (they are agonist substances).
Thus, in short, the main function of this substance is to slow down brain activity. Specifically, it acts by inhibiting neuronal synapses, limiting their excitation. A curious fact is that this neurotransmitter fails in cases of epilepsy.
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Location
GABA is distributed throughout the cerebral cortex . In addition, but, it is also distributed outside the Central Nervous System (CNS); Specifically, we find GABA in different organs, such as the lungs, pancreas, kidneys, liver, stomach, skin or reproductive organs, among others.
receivers
GABA brain receptors are diverse: GABA A and GABA C (where a Calcium channel [Cl-] intervenes) and GABA B (where a potassium channel [K+] intervenes). We also find benzodiazepines, steroids and the alcohol.
Functions
GABA’s main function is to provide a sense of calm . Thus, having balanced levels of GABA makes our anxiety levels controlled; this facilitates a feeling of relaxation, calm and peace.
Other functions in which GABA is involved are sleep processes, vision, muscle tone, motor control and growth.
1. Sleep facilitation
GABA is known to aid sleep. Specifically, it has been proven how taking a dose of between 0.5 and 5g of GABA before going to sleep stimulates melatonin production and reduces the body’s (and brain’s) arousal.
2. Growth
GABA also enhances growth hormone synthesis. This hormone is responsible for muscle growth while playing sports, and for tissue regeneration at night. Thus, some studies suggest that GABA is involved in muscle growth (especially when we sleep).
GABA agonists
On the other hand, we find different GABA agonist substances (this means that they increase its concentration or enhance its effects). They are the following.
1. Benzodiazepines
Benzodiazepines are indirect GABA A receptor agonist drugs (this means that they enhance the depressant and “anti-stress” effect of this substance). Specifically, they act on the cerebral cortex and the limbic system.
These are anxiolytic drugs that reduce anxiety and also act as muscle relaxants. Benzodiazepines are not only indicated for anxiety disorders, but also for depression, insomnia, and alcohol withdrawal. Even so, it should be noted that they are not drugs of choice for any disorder, due to their high addictive potential and the high dependence they cause.
2. Barbiturates
Barbiturates, also GABA agonists, are the first anxiolytics to be used. Currently, however, they are no longer in use (discontinued) and are not prescribed except in exceptional cases, due to their high toxicity and low safety.
3. Alcohol
Alcohol is a potent CNS depressant . It is a GABA A receptor agonist, like benzodiazepines (they share a mechanism of action). In addition, it is also an antagonist of glutamate (the main excitatory substance in the brain).
Alcohol is the second most consumed addictive substance worldwide (8.5% of the population over 18 years of age consumes it), after nicotine. A curious fact about it is that it is the only addictive substance with which you can die in the context of a withdrawal picture (withdrawal syndrome).
Related disorders
Alterations in GABA have been related to different disorders and diseases . These alterations translate into a dysfunction of this neurotransmitter. Specifically, it has been related to:
1. Panic disorder
Panic disorder is an anxiety disorder where GABA deficits have been found in people who suffer from it. This deficit can be solved with benzodiazepines, for example, which are GABA agonists.
2. Schizophrenia
Alterations in GABA have also been found in patients with schizophrenia ; Specifically, there has been talk of abnormalities in the genes that control this neurotransmitter, as well as others (dopamine, glutamate, acetylcholine…). This is one of the genetic hypotheses of the etiology of this disorder.
3. Dementias
Some types of dementia have also been linked to dysfunctions in GABA, for example Alzheimer’s disease dementia, Lewy body dementia and frontotemporal dementia.
It appears, however, especially in subcortical dementias, where the decrease in GABA is characteristic together with the decrease in dopamine , which is related to motor symptoms, slowing down and decreased motivation (apathy, asthenia and abulia).
4. Movement disorders
Alterations in GABA , specifically lower than normal levels of this substance, have also been found in some movement disorders. For example in Parkinson’s, Huntington’s chorea or tardive dyskinesia.
5. Anxiety disorders in general
In addition to the aforementioned panic disorder, numerous anxiety disorders are associated with a decrease in GABA. Some studies show how low levels of GABA increase the probability of developing an anxiety disorder , and conversely, high levels of this substance “protect” against anxiety.
It is for all these reasons that anxiolytic drugs are generally used for patients with anxiety disorders; It should be noted, however, that these pharmacological treatments should preferably be accompanied by a coadjuvant psychological therapy.
How to increase GABA naturally?
We have seen how deficits in GABA can cause mental health problems. This leads us to ask ourselves, can we increase GABA in our body naturally, without the need for drugs? The answer is yes. How do we do it?
Mainly through diet. Our body synthesizes GABA from an amino acid called glutamic acid, linked to vitamin B6 (pyridoxal phosphate). These two elements can be found in different foods, following a healthy diet. Some of these foods are: vegetables, onions, raw nuts, soybeans, tomato and free-range eggs.
In this way, a balanced diet and healthy eating can help us increase the concentration of GABA in our body, thus reducing the probability of developing health problems, especially mental health (for example, anxiety).
Bibliographic references
- Abdou, AM (2006). Higashiguchi S, Horie K, Kim M, Hatta H, Yokogoshi H. Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans. Biofactors, 26(3):201-208.
- Netter, F. (1989). Nervous system. Anatomy and physiology. Barcelona: Salvat.
- Stahl, SM (2002). Essential psychopharmacology. Neuroscientific bases and clinical applications. Barcelona: Ariel.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.