Forget about morphine
Erasing memories cured animals of drug addiction
Anatoly Glossev, Vesti
Neuroscientists cured experimental mice of drug addiction by blocking drug-related memories in their brains. Similar treatment tactics can be applied to people in the future.
The achievement is described in a scientific article published in the journal Neuron (Keyes et al., Orchestrating Opiate-Associated Memories in Thalamic Circuits).
The brain requires us to avoid pain and strive for pleasure. This is an ancient and incredibly powerful behavioral mechanism. It is nurtured and fixed by natural selection, because usually we enjoy things that are useful for survival and reproduction, such as comfort, safety, food, sleep, sex.
But, unfortunately, mankind has invented drugs. Even sex does not bring a person as much pleasure as opiates. The brain of an addict remembers this experience and strives to repeat it. As a result, psychic forces that are older than consciousness and will push a person to the disastrous path.
Those who managed to escape from the embrace of the white death say that there are no former addicts. There are those who decide again and again every day not to do it today. Often, sooner or later a person gets tired of fighting with himself. Hence, the biggest problem in the fight against opioid addiction is relapses.
But what if an addict could just forget the pleasure that the drug gave him? It seems that scientists have now achieved just that. However, so far only in experiments on mice.
Biologists had genetically modified animals at their disposal, the activity of neurons of which can be monitored and controlled using optogenetics methods.
The researchers gave the rodents a choice: to be in one of two parts of the chamber that differ in appearance and touch. In the first of them, animals were injected with saline solution (in other words, salted water), and in the second – morphine. It is not surprising that already on the fifth day the mice confidently headed to the part of the chamber that promised them pleasure.
The experimenters found a neural network in the brains of experimental rodents, in which the "memory of the drug" was stored. To do this, biologists placed animals suffering from withdrawal ("withdrawal") in a chamber in which they usually received the drug. At the same time, scientists closely monitored the activity of neurons, which, as has been proven in previous studies, are associated with the development of addiction.
The key element of morphine memory was the pathway connecting the paraventricular nucleus of the thalamus with the central nucleus of the amygdala.
At the next stage of the work, biologists temporarily blocked this chain of neurons. Then the mice stopped confidently choosing the "morphine" part of the camera.
After that, the efficiency of the neural pathway was restored by scientists. But, to the surprise of the experimenters, the animals continued to "randomly" choose which part of the camera they liked best.
Two weeks later, the rodents still did not remember that something pleasant was happening to them somewhere here. Even repeated administration of the drug did not activate these memories, as if they were completely erased.
"We haven't studied time points for more than two weeks," says Xiaoke Chen, head of the research group at Stanford University. "But we think it's very likely that the memory [of the drug] has disappeared."
The idea suggests itself that drug addicts can be treated in this way. Of course, doctors will not have genetically modified people whose neurons can be controlled using optogenetics. But scientists suggest that it could be replaced by stimulation of neurons with electrodes – a method sometimes used, for example, to combat Parkinson's disease.
Of course, the effectiveness and safety of such treatment has yet to be tested. However, such a possibility is very encouraging: the method based on this discovery could save more than one human life from painful death.
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