Dopamine 101 and Its Effect on Eye Vision and Cancer


What is dopamine? Each of us heard about this hormone at least once. It is called the hormone of happiness, joy, pleasure, or the hormone that controls passion.

The team would like to share with you the ways how changing the concentration of the dopamine hormone in the human body helps to quit smoking, provokes the occurrence of gambling addiction and shopaholism, causes myopia, and also helps fight cancerous tumors.

What is dopamine?

Dopamine is an active chemical produced by the human brain, as well as a hormone produced by the adrenal glands. Dopamine is naturally produced during processes that a person enjoys, which is why this substance is used by the brain to evaluate and consolidate the actions that will be important for later life.

Dopamine receptor agonists, i.e. substances that stimulate the activity of dopamine receptors and increase hormone production, are used to ease the progress of certain diseases, such as Parkinson’s disease. Scientists conduct numerous studies aimed at elucidating the role of dopamine in other processes – the formation of various addictions, cancer treatment and even smoking cessation.

Gene helps quit smoking

The presence of a specific variant of the Taq1A gene called Taq1A A2/A2 in the human DNA can have a direct effect on a person’s ability to quit smoking. A study by an international group of scientists led by Ma Yunlong from the School of Medicine of Zhejiang University was published in the Translational Psychiatry journal and the Nature journal.

The Taq1A A2/A2 gene encodes the activity of dopamine receptors, thereby changing the degree of their activity. Excess dopamine in the human brain, in turn, contributes to the formation of nicotine addiction, so the brain begins to “realize” that smoking is fun, which means it is an action that needs to be repeated.

Scientists analyzed the results of 22 studies containing data on 11,075 people, 9,487 of whom were representatives of the Caucasian race. The authors of the study claim that they were able to detect a pattern:

Caucasian people, whose DNA had a specific variant of the Taq1A gene (Taq1A A2/A2), were much more likely to successfully cope with nicotine addiction and quit smoking than those who possessed the Taq1A A1/A1 or Taq1A A1/A2 genes.

The authors of the study emphasize that their work needs further verification, and it is too early to apply the findings in practical medicine.

Gambling addiction as a side effect of treatment

Another group of researchers found that doctors have long overestimated the effectiveness of dopamine receptor agonists, using them to combat Parkinson’s disease and mental disorders.

Agonist drugs act on dopamine receptors, causing them to work more actively. Excess hormones provoked the formation of various mental disorders and addictions.

1,580 cases of addiction, resulting from side effects of drugs, have been recorded in 21 countries of the world over the period of ten years. These cases included 628 episodes of the emergence of gambling addiction, 465 cases of the formation of hypersexuality and 202 cases of shopaholism. Of the 1,580 diagnoses, 710 owed their appearance to dopamine receptor agonists, and the remaining 870 – to all other types of drugs affecting the hormonal background. More details on the study can be found in the JAMA Internal Medicine journal.

Dopamine against Cancer

Researchers from Ohio State University, supervised by Sujit Basu, still advise using dopamine as a medicinal treatment of cancer. A related article was published in the International Journal of Cancer.

Scientists said that the use of dopamine significantly slows down the growth of blood vessels in a malignant tumor, and this is one of the most important factors in its growth, since blood vessels provide nutrition to cancer.

In addition, researchers argue that the use of dopamine reduces the negative effect of 5-fluorouracil (an antitumor substance that is used during chemotherapy) on the patient’s blood composition.

No dopamine leads to myopia

Last summer, scientists said they had found out the real cause of myopia in modern adolescents. The article about the research was published in the Nature journal.

In recent decades, myopia has become an epidemic: in Europe and the United States, the number of myopic people has more than doubled over the past century, and in Asian countries the situation is even worse. For example, 10–20% of the Chinese suffered from myopia 60–20 years ago, but now the figures have already reached 90%. In Seoul, 95.6% of 19-year-olds are shortsighted.

For many years, doctors have investigated the causes of myopia, such as lengthening of the eyeball and focusing the image in front of the retina rather than on it. In the process, it turned out that neither genetics nor the habit of modern people to spend a lot of time reading and in front of monitors of electronic devices are decisive causes of the disease. The authors of the study stated that myopia is caused by the lack of daylight.

Modern people began to spend much less time outdoors, and this provokes the occurrence of myopia, since the retina of the eye produces dopamine under the influence of bright daylight, and its lack causes lengthening of the eyeball.

Doctors believe that in order to maintain good vision, a person needs to spend at least three hours a day under the lighting of 10 thousand lux (brightness of the sunlight), while the most powerful indoor lighting usually does not exceed 5 thousand lux.