The secretion of a hormone modifying the neuronal response in women could explain why they are more vulnerable than men to alcohol.
- Women are more vulnerable to alcohol than men.
- This could be explained by high levels of estrogen in their brains.
- Estrogen would activate dopamine, linked to the reward circuit in the brain.
In France, alcohol kills about 41,000 people a year. However, if in the land of wine, consumption tends to decrease overall, that of women is gradually joining that of men. It is clear that the two sexes are not equal when it comes to alcohol. Not only are women who drink socially less well regarded, but alcohol also affects their organism more. In particular, it has been proven that the blood alcohol level appears higher in a woman than in a man with the same amount absorbed. Elimination of alcohol is also slower in women. If a smaller liver and a less important corpulence can explain these phenomena, the biological mechanisms involved remain unclear. Today, a new study published in The Journal of Neuroscience shows that the secretion of a hormone modifying the neuronal response in women could explain this difference.
For their study, the researchers worked on mice, whose brains are quite similar to those of humans. They activated estrogen receptors (a group of steroids whose natural function is to be a primary female sex hormone) in the ventral tegmental area (ATV, a group of neurons located right in the center of the brain) of male and female mice. They were then able to observe that activation of the estrogen receptor ERα inflames neurons in response to alcohol.
Estradiol (E2) levels increase and alter the dopamine system, a neurotransmitter in several pathways of the nervous system, including that of reward. When E2 levels are high, ATV neurons react more intensely to the presence of ethanol and release dopamine. Abuse is then more likely, alcohol consumption being more “rewarded” by the nervous system of female mice than that of males.
“Women transition to an alcohol use disorder faster”
The scientists then blocked certain receptors (ERa and ERb) in the ATV of mice. While it decreased alcohol abuse in female mice, it had no effect on males, although their brains also contain estrogen. It is therefore possible that, in females, estrogen receptors are more sensitive to activation when levels change, the researchers suggest. Thus, estrogen is said to have “potent effects” on the dopamine system and increase women’s vulnerability to developing alcohol dependence.
“These results indicate that different brain mechanisms cause excessive alcohol consumption in women and men, explains Amy Lasek, psychiatrist at the University of Illinois (USA) and co-author of the study. If alcohol consumption is higher during times when estrogen levels are high, this can both contribute to alcohol-related health risks and also increase the risk of developing alcoholism problems. severe”she explains to the site Reverse. “Women move more quickly from problematic alcohol use to alcohol use disorder and suffer the negative health effects of alcohol, such as increased risk of cancer, liver damage, diseases heart and brain damage”, she continues.
In particular, it has already been proven that with equal alcohol consumption, women have more long-term sequelae. They suffer more from neurological damage (peripheral polyneuritis causing pain or sensory disturbances in the extremities) and develop steatosis (fatty liver), hepatic fibrosis or cirrhosis earlier than men (5 to 7 years earlier on average).
A gender-based approach to the treatment of alcoholism?
“This is important because it means that different approaches might be needed to reduce heavy drinking in men and women,” developing Amy Lasek. So, ultimately, these findings could lead to innovative gender-based treatments for alcoholism.
Currently, there are already drugs that block estrogen receptors. Known as Selective Estrogen Receptor Modulators (SERMS), they are used to treat breast cancer. “However, SERMS have significant side effects like hot flashes, fatigue, and mood swings, so unfortunately using a SERM to block estrogen receptors in otherwise healthy women to reduce alcohol consumption is not a good option”, explains Amy Lasek.
What remains is to find specific signaling pathways by which estrogen receptors act in the brain, leading to increased excessive alcohol consumption and feelings of reward in women. This could lead to the development of a more targeted method to reduce excessive alcohol consumption in their homes. And this, without side effects, hope the researchers.
What consumption in France?
We speak of binge drinking when a person has a blood alcohol level of 0.08 g/dl or more, which is generally five drinks or more for men or four drinks or more for women in about two hours.
In France, the health authorities recommend a few days without alcohol in a week and, on the days when it is consumed, not to exceed the two so-called standard glasses. Overall, it is advisable not to consume more than 10 standard drinks per week.
Nevertheless, according to a French public health survey conducted in 2017, at that time, 9.7% of French people aged 18-75 said they had drunk more than ten glasses of alcohol in the last seven days. On the other hand, 7.9% said they had consumed it more than five days out of seven.”That’s about 10.5 million adults who drink too much. In any case, they drink in a proportion that increases the risks to their health, in particular the medium and long-term risks: cancers, hypertension, cerebral hemorrhages, certain cardiovascular diseases…”commented Viet Nguyen-Thanh, head of the addiction unit of Public Health France at AFP.
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