GABA
The amino acid glutamate is known to most people as a food additive and flavor enhancer in a variety of ready meals. However, glutamate is much more important for us as the most important excitatory neurotransmitter in our nervous system. In a way, glutamate is therefore the antagonist of GABA.
However, the two messenger substances are also very close in that GABA (y-aminobutyric acid) is produced by the body from glutamate. According to the current state of knowledge, glutamate plays an important role, especially for the control of movement, our memory, learning processes and sensory perception. At the same time, a connection between insomnia and a disturbed glutamate household is suspected, as is a connection of the messenger substance to the development of epileptic seizures.
Dopamine
Dopamine is perhaps one of the best known neurotransmitters. This is mainly due to its connection to the development of Parkinson’s disease. In this disease, the neurons of the substantia nigra (from Latin “black substance”) in the midbrain, which produces dopamine as part of the motor system, gradually die.
This results in the typical symptoms of lack of movement, stiffness of the limbs, and rest tremor. In later stages, other neurological and psychological symptoms such as depression and dementia are added. From this it can already be deduced what an important role dopamine plays in the course of motor functions, among other things.
Dopamine is also indispensable for the proper functioning of our attention and learning ability. In addition, dopamine is fundamentally involved in the functioning of the reward system of our brain and thus also our motivation. This can be seen, among other things, in the effects of drugs, whether it be alcohol, cigarettes or illegal drugs such as marijuana or cocaine, whose psychological dependence is based on the increased release of dopamine in the reward system.
However, more everyday activities, such as eating or having sex, also have an effect on precisely this system. Dopamine is also used in the body to synthesize norepinephrine, which is related to adrenaline and is involved in controlling emotions, alertness and motivation. Depression is a very widespread mental disorder, which is mainly manifested by negative thoughts and moods and the loss of joy, interest, drive and self-esteem.
Thus, depression is one of the so-called affective disorders. Healthy people can also suffer from such symptoms temporarily, but in their case they occur in a mitigated form and less frequently. Women are affected by depression about twice as often as men.
Depression is also more common in high-income countries. The mechanisms behind depressive disorders are still only partially understood due to their complexity. However, the most common theory on the cause of depression is based on a multifactorial developmental model.
Among other things, genetic, drug, hormonal, neurobiological and developmental risk factors are used as explanations for the occurrence of depression. It is considered certain that there are disorders at the level of signal transmission of the neurotransmitters. A whole range of different signal systems seem to be affected by this.
However, the serotonin, noradrenalin and dopamine systems play a special role. All three neurotransmitters seem to be released in too small amounts, but to varying degrees for each individual patient. This knowledge is used in the therapy of depression.
Several groups of antidepressants specifically intervene in the norepinephrine, serotonin and dopamine system of the brain by inhibiting the reuptake of these neurotransmitters. This counteracts the existing neurotransmitter deficiency so that the symptoms are alleviated. In the meantime, various groups of drugs are available for this purpose. However, tricyclic antidepressants are rarely used today due to their sometimes severe side effects, while the group of serotonin reuptake inhibitors (SSRI) and norepinephrine reuptake inhibitors (SNRI) have good effects and milder side effects.
