Drug dependence was associated with hunger, scientists have found

© Fotolia / SSilver Neurons in the human brainDrug dependence was associated with hunger, scientists have found© Fotolia / SSilver

Craving for drugs, and other elements of addiction affect the same neurons in the human brain that hunger, researchers found, published an article in the journal Nature.

«To put it very simply, in that moment, when you are hungry, a picture of cheeseburger can very strongly influence your behavior. When you are full, this same picture may suddenly become less appetizing. Those neurons «hunger» in the insular cortex, which are responsible for this reaction, can play an important role in the development of the inexplicable urge to overeating and drugs,» says Joab Rains (Yoav Livneh) from Harvard University (USA).

Enough scientists have long noticed that the behavior of former drug addicts and alcoholics and the probability of their return to the habit affects not only the structure of their psyche, but also the environment in which they live after rehabilitation.

As shown by numerous experiments conducted in recent years, the familiar faces of companions and other drug addicts, the room, the characteristic «paraphernalia» dependency – syringes, spoons, bottles and glasses – can make a person break and go back to the habit.

Livni and his colleagues found, what accounts for such relapses, observing the work of those regions of the mouse brain that are associated with digestion, search for food and hunger. Irregularities in their work, as the scientists explain, for a long time are linked with the development of obesity and extreme forms of overeating, which is largely similar to drug addiction.

For observations of these areas of cortex and deep layers of the brain, scientists are stuck in their cells with special genes that make the neurons glow when activated. This allowed the biologists to see how «lit up» the nerve cells in the center of hunger at the sight of the food and keep track of what other parts of the brain they affect.

Following these transactions, the Showers and his colleagues dropped the rodent in a special cage, one wall of which is three buttons with pictures of food that a rodent could either poke your nose or to lick. When you click on one of them in the bird feeder was falling portion of sweet syrup, and the other two filled her or plain water, or a bitter solution of quinine.

Watching the brain function of mice when you lick these buttons, scientists have tried to understand which of them are responsible for «switching on» feelings of hunger if food and «off» when receiving the portions of food.

As it turned out, this role performs a set of small nerves in the insular cortex of the brain, directly associated with the so-called AgRP-neurons – cells of the hypothalamus, the deep part of the brain acts as the «center of hunger». When the hungry mouse sees food, the cells in her insular cortex enforce AgRP-neurons, which increases hunger and causes rodents to actively seek food.

Opening such a relationship, the researchers checked how to change those cells, if you enable the «hunger center» to bypass the insular cortex. These experiments led to an unexpected discovery – it turned out that between the bark and AgRP-neurons there is a hidden feedback, which makes the mouse very much to respond to images of food even when she has had enough.

This relationship, as scientists believe, may explain why many people who suffer from obesity, can’t stop yourself and start is uncontrollably at the sight of food, and can also be one of the main reasons for the development of drug addiction and return to drugs after abandoning them. Accordingly, the suppression of the activity of AgRP-neurons can help fat people and former drug addicts to deal with cravings for food or drugs.