GABA is one of the most important inhibitory neurotransmitters in the human body. The main effects of GABA are reducing the excitability of nerve cells and relaxing muscle cells. However, this substance can also have a calming effect and make it easier to fall asleep, which is why some people eagerly reach for supplements containing GABA - can taking them really bring the expected results?
GABA (gamma-aminobutyric acid) is a neurotransmitter. However, before it was found out that this substance is important for the functioning of the nervous system, its presence in plant organisms and various microbes was first discovered.
GABA was synthesized for the first time in 1883, and it was only after less than a century - in 1950 - that it was found to be an important substance that also circulates in the central nervous system in mammals.
GABA: chemical structure and synthesis
GABA is an amino acid that is formed from glutamate. A specific enzyme is involved in the production of the neurotransmitter - glutamate decarboxylase - and the synthesis of GABA itself takes place with the participation of a cofactor, which is the active form of vitamin B6.
What the gamma-aminobutyric acid is made of is actually quite interesting. Well, glutamate is a stimulating neurotransmitter, and GABA has a completely opposite effect - it inhibits the activity of nerve cells.
GABA: CNS action
The basic action of GABA has already been mentioned above - after binding to its receptors, this neurotransmitter leads to a reduction in the excitability of neurons.
So far, three types of receptors for GABA have been discovered - they are A, B and C receptors. The most important in terms of the function of this substance are the first two of the following:
- GABAA receptors: structures that are ligand-dependent ion channels, their stimulation leads to the influx of chloride ions (Cl-) into the nerve cells
- GABAB receptors: a different type of receptors, because they are metabotropic receptors associated with the G protein, stimulation of these structures by GABA - via the G protein - results in the opening or closing of ion channels
Receptors for GABA are present in both pre- andpostsynaptic projections of neurons of the central nervous system.
The influx of chloride ions inside these cells results in hyperpolarization, i.e. a state where they become much less capable of excitation in them. Ultimately, this stops the transmission of impulses between individual neurons.
The inhibitory effect of GABA cells in the nervous system is, contrary to appearances, extremely important - because when neurons are excessively stimulated, it may be conducive to, e.g. the occurrence of a feeling of tension, but also anxiety or even lead to convulsions. Gamma-aminobutyric acid is generally recognized as a substance that can exert anxiolytic, sleep-inducing and sedative effects.
GABA affects not only the current functioning of the brain, but also it is important in the development of structures belonging to the nervous system.
It has been reported more than once that this substance affects the proliferation of neural progenitor cells, and its importance in the differentiation and migration of these cells is also mentioned. In the literature, you can also find information that GABA regulates the process of nerve fiber elongation.
GABA: action in other organs of the body
GABA is important not only for the cells of the nervous system, but also for many other structures in the human body. The influence of this neurotransmitter on muscle fibers is mentioned - it leads to their relaxation.
On the other hand, it is less often said about how GABA affects definitely other organs of the body - in practice, it turns out that this substance has many important functions.
We can mention here, for example, the pancreas, in which GABA regulates its endocrine activity. Pancreatic alpha cells can - apart from insulin - also secrete gamma-aminobutyric acid.
The neurotransmitter can then affect beta cells: they release an anti-insulin-acting glucagon, and when GABA binds to these cells, their hormone secretion may be temporarily blocked.
Other interesting reports on the relationship between the pancreas and GABA are those according to which this substance would affect the survival and replication ability of beta cells, but also that gamma-aminobutyric acid could transform alpha cells into beta cells .
In type 1 diabetes, the deficiency of alpha cells is one of the problems that arise in its course - if indeed GABA could transform cells present in the pancreas into thoseis missing, there would be a possibility of the emergence of a new method of treating this condition.
However, it is possible to find both receptors for GABA and the same neurotransmitter in many other human tissues. They were detected, among others both in the digestive tract, male and female reproductive system, liver, kidneys and lungs. However, the role of GABA in their case has yet to be fully established.
GABA: the use of the neurotransmitter and its effect on its receptors in medicine
In the medical world, GABA itself is rather not used - rather, substances that affect the receptors for this transmitter are used.
Basically, agents that can attach to these receptors and lead to increased attachment of their neurotransmitter to them are of greatest importance. Examples of such drugs that may enhance the effects of GABA include:
- benzodiazepines (primarily anxiolytic)
- barbiturates
- sleeping pills (such as zolpidem or zaleplon)
- valerian
- inhalation anesthetics
- baclofen
- propofol
There are also preparations that also affect GABA, but in a different way than by modifying the intensity of the attachment of this neurotransmitter to its receptors.
We are talking here about agents that, by blocking enzymes that break down GABA, lead to an increase in its amount (such drugs include valproates and vigabatrin) or about GABA analogues, which are, for example, pregabalin and gabapentin.
Since GABA has an inhibitory effect, it is suspected that its influence on this neurotransmitter could be used to manage a wide variety of human he alth problems.
Some applications of GABA - such as making it easier to fall asleep or reducing the intensity of anxiety - are said to be more, while other potential uses of this substance are still being researched.
There is mention of the possibility of using GABA in the treatment of hypertension, relieving the symptoms of premenstrual tension, relieving pain or even treating ADHD and meningitis.
There are also reports about the potential beneficial effects of influencing the GABA system in patients with chronic inflammation of the airways, Cushing's disease or Huntington's disease.
GABA: supplements
Looking at how many potential benefits can result from using GABA, it is hardly surprising that some people choose to use GABA.supplements containing this substance. It is impossible to state unequivocally whether GABA supplementation is actually effective.
This situation arises from the fact that, in fact, very contradictory news is flowing from scientific research. Well, just as some publications suggest that at least some of the orally ingested GABA reaches the central nervous system, according to others, it is completely the opposite.
It may be that before the neurotransmitter reaches the central nervous system, it is completely broken down. There are also reports that, in fact, orally ingested GABA does not cross the blood-brain barrier: if it were, then the consumption of GABA supplements could not lead to the expected effects of their use.
As emphasized, the results of the published research are often completely contradictory. Some people who take GABA supplements notice that, among others, improved mood, decreased sense of anxiety or the fact that it is much easier for them to fall asleep.
It is possible that the agent actually taken orally affects the central nervous system, but on the other hand, there are chances that the above-mentioned effects of taking GABA supplements appear due to the placebo effect in patients.
Read also:
- GABA supplementation: dosage and effects
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