Topic

3.3 Dopamine, GABA & Glutamate

Dopamine

Dopamine is a neurotransmitter that is central to our motivation, drive and interest in life. It can also be viewed as a neurotransmitter involved in stress, but stress of a positive nature, such as falling in love, exercising, sex, etc. It is the neurotransmitter that plays a role in addiction, as it is involved in alerting us to a potential reward – i.e. if a person is an alcoholic, then the sight or thought of a drink will cause an increase in dopamine activity in certain areas of the brain, and we get the sense that a reward is coming. Dopamine is also involved in things such as movement and mental focus. Low levels of dopamine at the extreme level can result in Parkinson’s disease, where neurons that produce dopamine begin to die off. Low-level deficiency can lead to lack of motivation, fatigue and poor concentration.

GABA & Glutamate

GABA and Glutamate are 2 neurotransmitters that have a yin-yang relationship. This is understood easily by looking at the diagram below whilst reading the information.

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GABA – gamma-aminobutyric acid is another neurotransmitter that is greatly involved with how we feel. It reduces anxiety and stress and regulates epinephrine and norepinephrine (see next topic), dopamine and serotonin. This neurotransmitter is vital in mood regulation. GABA is the major inhibitory pre-synaptic neurotransmitter in the brain and retina, produced from glutamic acid, using the enzyme glutamic acid decarboxylase (GAD) which is pyridoxine (Vitamin B6) dependant. 

Glutamate (Glutamic Acid) is an excitatory neurotransmitter – meaning it is stimulatory and gets things going. It is a very important neurotransmitter in learning and memory function. Its amino acid precursor glutamine (often used in sports supplements and by bodybuilders), used to be a prominent feature in the barrage of ‘brain food’ type supplements that were popular a few years ago. However, there had been questions over its safety and its potential to be an excitotoxin. We believe a little can be very beneficial. The balance of glutamate in the brain is a very finite one. It is vital for learning and memory, but excessive amounts are associated with neuronal dysfunction, and changes in glutamine levels are part of the pathological picture in issues such as Alzheimer’s, Parkinson’s and Tourette’s. This fine balance is essential.

As you can see from the diagram, glutamate (excitatory) is formed from L-Glutamine using the enzyme glutaminase and magnesium. Glutamate is then converted to GABA (inhibitory) using the enzyme amylase glutamate decarboxylase and vitamin B6, vitamin C, magnesium and zinc. If someone is lacking in the enzyme or nutrients then glutamate will not be converted to GABA effectively and levels of glutamate will build up leading to an excitatory state. Hence, you can see how supplementation with large amounts of L-glutamine (such as bodybuilder fuel) could be troublesome and lead to high levels of glutamate and an excitatory condition! Excess glutamic acid has been linked to neurodegenerative diseases such as Alzheimer’s, Multiple Sclerosis, Bipolar, Migraine and Schizophrenia. On a less serious level, a GABA deficiency or excess glutamate may cause anxiety, insomnia, trembling, panic attacks, palpitations, cold or clammy hands, ringing in the ears and carbohydrate craving. Hence, you can see why it is a fine balance and important to ensure we have all the right nutrients through food and allow our bodies to regulate the process.