The use of alcoholic beverages permeates the entire history of humanity. There are records that man stored fermented drinks produced with rice, fruits and honey since 8 thousand years before Christ, and since then we have increasingly elaborated our recipes and produced them on a large scale. Beer was very important to Sumerian, Egyptian and Babylonian societies, and served as a bargaining chip, while wine was in wide use among the Romans and gained geopolitical value for empires. And cachaça animated many parties of the planters, who sold and bargained in colonial Brazil. But what does science have to do with it?
During the Industrial Revolution, from the second half of the 18th century, when alcoholic beverages began to be produced in large volumes, the rate of alcoholism began to draw the attention of the authorities. It was then that the first studies on the effects of alcohol, its mode of action and consequences in the short and long term began.
Alcoholism, considered a disease, affects 4 million individuals in Brazil. We know that its development is not due to a single cause: it involves genetic, biological, social and psychological factors. And understanding why some people become dependent and others cannot be a valuable tool for public health.
In genetic terms, several genes related to the disease have already been identified. One of them, CYP2E1, participates in the production of enzymes that break down alcohol in the brain: people who produce more enzymes metabolize alcohol more and feel its effects more. In addition, alcohol acts on other systems in the brain, such as the reward system – drinking causes a feeling of pleasure. But this system starts to respond less and less, and so the person has to increase the amount of alcohol to feel the effects, and suddenly the situation goes out of control, like a snowball.
It is not easy to know if a person has these genes, and although he does not show any genetic propensity to become alcoholic, social environment and lifestyle play a decisive role. This is where some important collaborators come into the picture, helping us to uncover other characteristics that indicate a propensity to alcoholism.
At the UFRN Fish Laboratory there is a little fish called zebrafish that, by sharing 70-80% of its genetic material with us, works as a great model for studying human diseases.
Shy Zebrafishes that do not like new situations become more daring when exposed to low doses of alcohol, which would indicate that these individuals benefit from the experience and may seek the drug as a crutch when they need to face new or challenging situations, such as seeing themselves in a situation of predation or in an unknown social group. The drug reduces the anxiety of these individuals, who start to explore the aquarium more. More than that, we observed that this response can be monitored very early, starting at birth.
Zebrafish also allows us to study the effects of alcohol on pregnant women. The WHO (World Health Organization) estimates that the prevalence of alcohol use during pregnancy is 9.8%, that is, almost one in ten pregnant women drinks alcohol. About 77 out of every 10,000 births have fetal alcohol spectrum disorders, a condition that includes more severe cases, with very evident malformations, and milder cases, which are very difficult to diagnose – the child usually has a change in social behavior, hyperactivity and deficits. cognitive.
The zebrafish has helped us understand this disorder. We add alcohol to the water the embryo is in and assess the effects throughout life. Individuals with a more difficult diagnosis, for example, showed very high anxiety at the beginning of development (corresponding to the childhood stage between two and four years old), an indicator that can help in the detection of the disease and in the prescription of a treatment with chances of alleviating the condition.
Although zebrafish have helped us study alcoholism and answer many of the questions we have, there is still a long way to go. Anyway, we already know: we should drink in moderation and be alert if alcohol tolerance is high.
Ana Luchiari is a biologist and professor at UFRN.
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