Definition
Noradrenaline is a messenger substance (transmitter) produced naturally in the body, which belongs to the subgroup of catocholamines. It is produced from the neurotransmitter dopamine with the participation of an enzyme (dopamine beta hydroxylase). For this reason, dopamine is also called a precursor of noradrenaline.
The production takes place mainly in the adrenal medulla, but also in the central nervous system and in specialized nerve fibers. In the adrenal gland, dopamine is also used to produce the chemically related catecholamine adrenaline. Noradrenaline is involved in the regulation of various functional systems of the body.
Here, the control of cardiovascular functions should be emphasized. As a result, noradrenaline is regularly used in emergency medicine, for example, because it has a strong vasoconstrictive effect or increases the heart rate and is thus used to stabilize the circulation. In addition to its effects on the heart and blood vessels, noradrenaline influences subjective factors such as alertness, concentration and motivation.
A decrease or lack of this messenger substance has a negative effect on them. The situation is similar with regard to the formation of new memories in the memory. Furthermore, connections between a norepinephrine deficiency and the development of depression have been established.
This manifests itself in the established drug therapy with antidepressants, which inhibits the reuptake of noradrenaline into the nerve cells (SNRI = Selective Noradrenaline Reuptake Inhibitors and SSNRI = Selective Serotonin and Noradrenaline Reuptake Inhibitors). As a result, the available amount of noradrenaline remains longer in the space between two nerve cells and can therefore bind more to the specific receptors present. The binding causes different biochemical reactions in the corresponding cell, which in this case leads to an improved mood.
In addition, the success of the therapy manifests itself in an increased motivational drive of the affected person. A chronic, pathological lack of noradrenaline can be caused by a relatively rare metabolic disease. This is the so-called dopamine-beta-hydroxylase deficiency, which manifests itself in a lack of synthesis of noradrenaline from dopamine.
Characteristically, the dopamine level in the blood plasma is elevated, whereas the detectable amount of norepinephrine is reduced due to the low synthesis. Therapeutically, another precursor of noradrenaline is administered, which can be converted to noradrenaline without the involvement of dopamine beta-hydroxylase. The most important side effect can be an increase in blood pressure.
