Chicago scientists have discovered that the high activity of receptors for the female sex hormone oestrogen, Era the neurons of the ventral region of tyre in mice stronger excited in response to ethanol, reported in the Journal of Neuroscience. Other varieties of estrogen receptors is not so much change the nerve cells ‘ response to alcohol. Interestingly, the lock Era affects alcohol consumption by females, but not males. It is likely that mechanisms of development of alcoholism, the two sexes differ.
Humans, in rodents the likelihood of development of alcoholism is higher for female. The consequences of depending on ethanol for women is also more serious: they are due to the regular drinking bouts more frequently observed in liver, heart and brain and increases the risk of breast cancer. It is also known that women drink morewhen they have elevated blood levels of estrogen (17β-estradiol or E2). The same was shown in experiments on mice.
Estrogen acts as a hormone, when associated with the appropriate proteinreceptor on the surface of different cells or inside them and activate these receptors. Despite the fact that 17β-estradiol — a sex hormone, it, like other hormones, having an effect not only on the organs of the reproductive system, but also the brain, kidneys, bones and other organs. Activity what type of receptors to estrogen affects the perception of alcohol was not clear. But it is known that the formation of a dependency involves the neurons of the ventral region of tyre (ventral tegmental area, VTA) — part of the midbrain, and the estrogen receptors at least two types of Era and ERβ.
The effect of estrogen on cells of the VTA studied employees at the University of Illinois in Chicago under the leadership of Amy LASEK (Amy Lasek). They conducted electrophysiological experiments on brain slices passing through the ventral tegmental area, and set of behavioral samples in mice of both sexes. In the experiments in sections, scientists have recorded the electrical signals of neurons in the VTA, which arose in response to the addition of ethanol in the nutrient solution. While some of the products of the ventral region of tyre was acting agonists and antagonists of Era and ERβ receptors. This activated receptors or, conversely, suppressed. The researchers noted how the change in the activity of Era and ERβ in neurons of the VTA affects the response of these cells for the presence of alcohol.
To find out how activation of estrogen receptors acts on animals cravings to alcohol, the authors injected into the ventral tegmental area of living mice lentiviral vectors with small RNA from conifers structures (shRNA), which blocked the formation of Era or ERβ. Receptors exist for a certain time, and the small RNA was not allowed to be expressed the corresponding genes and to make new receptor proteins to replace the old one. Such animals, when they had recovered from the operation for the introduction of vectors, three times a week put in 2-4 hours a drinker with a 20% ethanol solution, and then measured the concentration of this alcohol in the blood.
When the activity of Era in neurons of the ventral region of tyre were raised, they often (p<0.0001) discharged in response to the presence of ethanol. Activation of the ERβ had no effect at all. Rather, the estrogen in this case acts through glutamate: one of the types of receptors for this neurotransmitter, mGluR1, tied to Era, and introduction of mGluR1 antagonist negated the effect of the activation of Era. In behavioral experiments, the lock-education Era by 30 percent reduced the amount of alcohol that was consumed by the mice, and ERβ by 16 percent. The effect was observed only in females, although in the VTA of males also have estrogen receptors. It is likely that mechanisms of development of dependence on ethanol in the two sexes unequally.
Mechanisms of development of alcohol dependence and the ways of dealing with it in the majority of cases studied in mice and rats. For example, in 2019, foundthat rats that periodically injected a needle for acupuncture to a certain point on the wrist, much less used the opportunity to drink than animals-alcoholics that did not use acupuncture. It is assumed that acupuncture changed the psychological effect of the adoption of ethanol. Another way to reduce consumption is to block the enzymes that metabolize ethanol and its decay products. In mice, this method showed acceptable results. However, it should be remembered that the ability to convert ethanol into other substances significantly varies in different mammals. In primates and bats it is much higherthan in rodents. Therefore, it is possible to test the means of dealing with alcoholism in some cases it is better for them.