How dopamine works
Dopamine action in the central nervous system
In the brain, dopamine is used for communication between nerve cells, i.e. it is a nerve messenger (neurotransmitter). In certain “circuits” it mediates positive emotional experiences (“reward effect”), which is why it – like serotonin – is considered a happiness hormone. Compared to serotonin, however, dopamine tends to increase motivation and drive in the longer term.
One of the diseases in which a deficiency of dopamine in the central nervous system (CNS) occurs is Parkinson’s disease. Typical Parkinson’s symptoms include muscle rigidity (rigor), tremor (tremor), and slowing of movements to the point of immobility (akinesia). Treatment with dopamine can help with these symptoms.
However, since the active ingredient is unable to cross the blood-brain barrier, it cannot be administered directly, thereby compensating for the deficiency in the brain. Instead, a precursor (L-DOPA) and analogues (dopamine agonists) of the neurotransmitter are administered, which can reach the site of action in the brain.
In schizophrenic or other psychotic patients, the concentration of dopamine is usually elevated in certain regions of the brain. In this case, inhibitors of the neurotransmitter (dopamine antagonists) are used. They belong to the group of antipsychotics.
Degradation and excretion of dopamine
After injection or infusion, half of dopamine is broken down within five to ten minutes and excreted in the urine.
When is dopamine used?
Dopamine is not used directly for neurological indications (such as Parkinson’s disease). Instead, precursors or analogs of it are administered because, unlike dopamine, they can cross the blood-brain barrier.
For circulatory stabilization, the drug is used in cases of shock or impending shock. These can occur, for example, in the following cases:
- heart failure and heart attack
- severe infections
- sudden, severe drop in blood pressure
How dopamine is used
Infusion and injection solutions are available for intravenous use of dopamine. It is administered by a physician.
L-DOPA as well as dopamine agonists and dopamine antagonists are available in tablet form. The frequency of use and dosage is determined individually by the treating physician.
What are the side effects of dopamine?
What should be considered when using dopamine?
Contraindications
Dopamine is mainly used in emergency medicine. The attending physician will clarify on an individual basis if a patient is not allowed to receive the medication for certain reasons.
Age restriction
Dopamine can be used from birth if indicated. Due to a lack of data, there are no firm dose recommendations in infancy.
Pregnancy and Lactation
Dopamine may be administered for life-threatening conditions during pregnancy and breastfeeding.
How to get medicines with dopamine
Only clinics and doctors can buy dopamine. It cannot be prescribed by prescription and cannot be obtained in any other form by patients.
The effect of dopamine ingested through meals (a diet rich in fruits and vegetables such as bananas, potatoes, avocados, and broccoli) is negligible because the active ingredient becomes ineffective (deactivated) in the intestines shortly after absorption.
Since when is dopamine known?
It was only the discovery that there is a completely different distribution pattern in the brain for dopamine than for adrenaline that led the scientists Arvid Carlsson, Åke Bertler and Evald Rosengren at the Pharmacological Institute of Lund University (Sweden) in 1958/59 to the assumption that dopamine has a significance all its own.
Using various experiments, the researchers discovered the greatest concentration of dopamine in the corpus striatum, a central brain region. Through experiments with the plant substance reserpine, they were able to demonstrate that the depletion of dopamine stores in this brain area leads to Parkinson’s-like symptoms.
A short time later, Oleh Hornykiewicz at the University of Vienna was also able to show through color reactions with extracts of the corpus striatum that these brain areas contain remarkably little dopamine in Parkinson’s patients.
In 1970, scientists Ulf Svante von Euler-Chelpin and Julius Axelrod (involved in the discovery of epinephrine and norepinephrine) were awarded the Nobel Prize in Medicine or Physiology “for their discoveries concerning the chemical transmitters in nerve endings and the mechanism of their storage, release, and inactivation.”
In 2000, Arvid Carlsson and other researchers won the Nobel Prize in Medicine or Physiology “for their discoveries on signal translation in the nervous system.”
More interesting facts about dopamine
Certain drugs such as cocaine are considered so-called dopamine reuptake inhibitors – they can prevent the reuptake of released dopamine into its cell of origin, which leads to an increased effect of the happiness hormone dopamine.
The brain thus associates drug use with a reward effect, which primarily explains the addictive effect of cocaine and other drugs. After excessive drug use, clinical pictures of psychosis often emerge as well.
