Dopamine and addiction
By upsetting and excessively stimulating the body’s reward system, dopamine can lead to the development of an addiction. For example, when taking drugs, dopamine has an increased effect. This leads to a positive feeling that one can become addicted to.
This increase in dopamine is triggered by the use of drugs such as amphetamines, opiates and cocaine. But alcohol and nicotine can also lead to this. When smoking, for example, dopamine is released as soon as you light a cigarette.
Use of dopamine as a drug
For some diseases it may help to administer dopamine or a precursor of dopamine as a drug. This is the case in the treatment of Parkinson’s disease. Here, patients are given a precursor of dopamine, L-DOPA (levodopa).
Dopamine itself is not given. It cannot pass from the blood into the brain because it cannot cross the blood-brain barrier. L-DOPA, on the other hand, can cross this barrier and is then converted into active dopamine.
In order to prevent this from happening before it reaches the brain, it is necessary to combine L-DOPA with another substance that prevents this from happening but does not itself enter the brain. This is how combination drugs, the carbidopa or the benserazide, are created for the treatment of Parkinson’s disease. These drugs are also used for restless legs syndrome. Dopamine is being used less and less for the treatment of shock or low blood pressure because the risk of side effects, such as cardiac arrhythmia, is relatively high.
Dopamine – Values
Dopamine levels vary from person to person and are probably responsible for some people being rather calm and lethargic while others are excited and active. Measuring the level of dopamine in the body is not part of a standard examination.Only if tumors in the adrenal medulla (pheochromocytomas) are suspected, the dopamine level is determined, since these tumors, especially if they are malignant, often produce increased dopamine. The value is usually measured in 24-hour urine and is normally 190 to 450 micrograms per day in an adult.
In children under 4 years of age, the value is significantly lower. The value can also be determined in the blood, where the normal value for adults is a few nanograms per liter. A lowered value in the urine or blood usually has no significance if there are no symptoms. However, an elevated value indicates a dopamine-producing tumor.