Introduction[edit | edit source]
Gamma-aminobutyric acid (GABA) is an amino acid that serves as the primary inhibitory neurotransmitter in the brain and a major inhibitory neurotransmitter in the spinal cord. It exerts its primary function in the synapse between neurons by binding to post-synaptic GABA receptors which modulate ion channels, hyperpolarizing the cell and inhibiting the transmission of an action potential. Muscle tone depends on the GABA, so the deficits of this neurotransmitter are related to hypertonia and rigidity.
Synthesis and Release[edit | edit source]
GABA is a naturally occurring amino acid that acts as a neurotransmitter in brain and spinal cord. Like other amino acids, it has a carboxylic (-COOH) group and an amino group (-NH3). It is a derivative of glutamate, a non-essential amino acid that is abundantly present in the body.
- It is synthesized from glutamic acid (glutamate) in the inhibitory neurons. These inhibitory neurons which produce GABA are referred to as GABAergic neurons. The glutamic acid undergoes decarboxylation reaction to form GABA. This reaction is catalyzed by glutamate decarboxylase enzyme.
- The release of GABA occurs by the same mechanism as followed by other neurotransmitters. When a nerve impulse reaches the pre-synaptic neuron, it causes degranulation of the vesicles containing GABA.
- As a result, GABA is released into the synaptic cleft and is ready to exert its action on both pre-synaptic as well as post-synaptic neurons.
Disorder in GABA Signaling[edit | edit source]
Low levels of GABA in the brain may play a role in stress disorders, anxiety disorders, and sleep disorders eg insomnia. GABA is made naturally in your brain, but it is also present in some foods and in bacteria. Supplements of GABA have been produced from fermenting bacteria. Because the idea of a natural brain tranquilizer is appealing, supplements are widely available and they claim to help people sleep and reduce stress or anxiety. However more studies are needed before any inferences can be made about the efficacy of oral GABA consumption on eg stress and sleep. Results to date show that there is limited evidence for stress and very limited evidence for sleep benefits of oral GABA intake.
Decreases in concentration of GABA have been reported in a number of clinical scenarios, including:
- Epilepsy: decreased with recent seizures
- Stiff person syndrome
- Major depressive disorder, bipolar disorder and Schizophrenia
- Chronic primary insomnia
GABA Analog[edit | edit source]
GABA analogs were designed because it is difficult to administer GABA itself (previous attempts at developing an intravenous or oral GABA drug have been unsuccessful). These help to restore levels of GABA. GABA analogs may be used to treat certain conditions associated with rapid nerve firing. Examples include:
- Neuropathy, resulting from diabetes, amputation, shingles, or another cause
- Restless legs syndrome
- Seizures and epilepsy.
GABA analogues include:
|Generic name||Brand name examples|
Exceptions[edit | edit source]
GABA is the “primary inhibitory neurotransmitter of the brain”. However exceptions are being found on a regular basis) eg Neurons in the striatum release GABA that inhibits the action of neurons in the globus pallidus. These neurons normally inhibit areas of the thalamus that are necessary for movement but when they are inhibited the thalamus is essentially freed up, allowing us to move.
References[edit | edit source]
- Jewett BE, Sharma S. Physiology, GABA.2018 Available:https://www.ncbi.nlm.nih.gov/books/NBK513311/ (accessed 2.5.2022)
- Healthy way magazine Neurotransmitters: Definition, 10 Main Types And Functions Available: https://healthywaymag.com/science/neurotransmitters (accessed 2.5.2022)
- Human memory GABA Available:https://human-memory.net/gaba/ (accessed 2.5.2022)
- Hepsomali P, Groeger JA, Nishihira J, Scholey A. Effects of oral gamma-aminobutyric acid (GABA) administration on stress and sleep in humans: A systematic review. Frontiers in neuroscience. 2020:923. Available:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527439/ (accessed 2.5.2022)
- Radiopedia GABA peak Available:https://radiopaedia.org/articles/gamma-aminobutyric-acid-gaba-peak (accessed 2.5.2022)
- Drugs.com GABA Available: https://www.drugs.com/drug-class/gamma-aminobutyric-acid-analogs.html (accessed 2.5.2022)
- Neuroscientifically Challenged The many sides of GABA Available:https://neuroscientificallychallenged.com/posts/many-sides-of-gaba (accessed 2.5.2022)