Norepinephrine is a neurotransmitter closely related to epinephrine that is synthesized naturally in the body. It acts both as a stress hormone and as a neurotransmitter. Like its chemically related messengers adrenaline and dopamine, it belongs to the group of catecholamines.
Table of Contents
- What is norepinephrine?
- How does norepinephrine work?
- Norepinephrine synthesis
- What problems can a norepinephrine deficiency cause?
- Can norepinephrine levels be measured?
- Increase of the norepinephrine level
- Interesting facts about noradrenaline
What is noradrenaline?
Norepinephrine is a neurotransmitter that is synthesized independently in the body. As the name suggests, it is closely related to adrenaline. Since norepinephrine does not have a methyl group on its amino group compared to epinephrine, the two messengers have partially different physiological effects. The interesting thing about noradrenaline is that it acts both as a hormoneas well as a neurotransmitter unfolds its effect.
How does norepinephrine work?
Norepinephrine has two fundamentally different modes of action in the human body. On the one hand it acts as a hormone and on the other hand as a neurotransmitter. Generally it controls the heart rate and initiates the ...escape reflex. It therefore ensures that, for example, in unpleasant situations, you suddenly feel very energetic and feel the need to flee from the situation.
Effect as a hormone
Noradrenaline is produced in the adrenal glands as a hormone. This occurs in parallel with the production of adrenaline. It is then released into the blood, which provides the escape reflex. For this reason it is also called the stress hormone. In the blood it causes a constriction of the blood vessels, which increases the blood pressure.
In addition to the constriction of the vessels, the glucose content in the blood is also increased, as reserves are broken down and the blood flow to the skeletal muscles and thus the oxygen supply is increased. This enables, among other things, a better ability to react, which is again associated with the flight reflex.
Effect as a neurotransmitter
As a neurotransmitter, noradrenaline fulfils its more important role for the central nervous system and sympathetic nervous system. This is also the most important difference from adrenaline, which is not considered to have a major role as a neurotransmitter. It maintains the heartbeat and regulates its frequency. It can also affect blood circulation to muscle tissues. In general, norepinephrine thus controls various parts of our organism via electrical impulses. Thus, noradrenaline also influences the control of appetite, motivation and motor function.
The biosynthesis of norepinephrine in the human body occurs in several steps. The amino acid tyrosine is hydroxylated to levodopa by tyrosine hydroxylase. A CO2 molecule is then split off from this substance. This produces the neurotransmitter dopamine. Dopamine is now finally oxidized by the enzyme dopamine hydroxylase, i.e. an oxygen atom is added and finally catalyzed to norepinephrine.
What problems can a norepinephrine deficiency cause?
Noradrenalin has a positive effect on the heart, blood pressure and blood vessels. A Deficiency has a negative effect on these factors. Furthermore, concentration, motivation and memory suffer with a norepinephrine deficiency. A noradrenaline deficiency can also be the beginning of depression. Drug treatment with antidepressants tries to inhibit the reuptake of norepinephrine in the nerve cells, as this allows more norepinephrine to remain between the nerve cells and thus bind to the corresponding receptors.
Thus, there should always be a balanced level of norepinephrine in the body, since norepinephrine is responsible for the regulation of various functional systems in humans. Especially the cardiovascular system is stabilized by norepinephrine and also in emergency medicine it is often used because it constricts the vessels or increases the heart rate, which is good for the circulation.
On the other hand, an increased noradrenaline level is also not a good sign. It indicates stress, high blood pressure and, in the worst case, even tumours, which can be malignant or benign. In any case, they cause an increased production of norepinephrine and can be detected in this way.
Can the noradrenaline level be measured?
Yes, for this purpose urine is collected over 24 hours, which is used for a complete measurement. The amount of norepinephrine found in the body is then interpreted using reference values. An increased noradrenaline level, for example, can then indicate high blood pressure or stress.
Increasing the level of noradrenaline
In order for norepinephrine to be synthesized in the body, various chemical processes are necessary. To ensure this, it makes sense to eat as much protein-rich foods as possible so that you have enough tyrosine in your body.
Furthermore, it makes sense to supplement your diet with foods that are considered "precursors" to catecholamines. These include apples, beetroot or bananas.
In this way, amino acids such as L-tyrosine can be produced in the body through the degraded proteins. From this, dopamine is secreted, from which noradrenaline is secreted.
Interesting facts about noradrenalin
A very interesting study, which has also provided important findings for drug treatment, was carried out in the Department of Molecular Psychiatry of the Center for Translational Research at the University Hospital for Psychiatry and Psychotherapy in Bern.
The aim was to find out more about the relationship between noradrenaline deficiency and depression and depression. They also looked at the difference between serotonin deficiency and norepinephrine deficiency.
It was found that norepinephrine deficiency was associated with depression symptoms. For the most part, it provoked poor concentration, anxiety, and listlessness.
In contrast, serotonin deficiency provoked other depressive moods such as hopelessness and sadness.
Another interesting study came to light in the U.S. in 2011 when there was a shortage of norepinephrine as a medication in hospitals. As a result, more dopamine and phenylephrine were prescribed.
The result of the study of 251 cases was that the death rate increased in patients with septic shock. On the one hand, this shows that norepinephrine is of great medical relevance, especially in emergency medicine. On the other hand, it also illustrates the dependence of medical institutions on various drugs. For this reason, research in the respective fields is very important to better synthesize norepinephrine and to find possible substitutes.