One glass is enough

Alcohol caused addiction in mice after the first use

Roman Fishman, N+1

The very first experiences of alcohol consumption change the brain forever, determining many habits and addictions of the future. Experiments on mice have shown how quickly the pathways of the dopaminergic system of the brain change, forming an addiction to alcohol. The results of the new work (Beckley et al., The First Alcohol Drink Triggers mTORC1-Dependent Synaptic Plasticity in Nucleus Accumbens Dopamine D1 Receptor Neurons) are published by the Journal of Neuroscience, the press release of the Jackson Laboratory That first drink is a learning experience briefly writes about it.

Dorit Ron, a professor at the University of California at San Francisco (UCSF) and her colleagues explain that single use of alcohol and other drugs leads to a constant strengthening of synapses at the beginning of the dopaminergic pathways of the "internal reward system" in the neurons of the ventral region of the tire - this has been shown by previous studies. However, the effect of a single alcohol intake on one of the most important "target areas" of these pathways – the nucleus accumbens – has not yet been studied, and scientists have focused their attention on it only now.

Starting, like all pathways of the dopamingergic system, from the neurons of the ventral region of the tire, the signals then reach the nucleus accumbens. Here they integrate with sensory data and emotional stimuli, leading to the initiation of appropriate motor reactions and forming behavior. The structures of the nucleus accumbens contain neurons carrying dopamine receptors D2 and D1. Therefore, for experiments, scientists used genetically modified mouse lines, whose D1 and D2 receptors carried fluorescent labels that allowed them to be examined on preparations.

The experimental group of mice had access to 20% alcohol and water during the day, and the control group had access only to water. Indeed, the experimental rodents showed increased activity of dopamine D1 receptors. It was accompanied by an increase in the activity of the target protein complex rapamycin (mTORC1), which stimulates cellular processes of translation of matrix RNA (mRNA). Moreover, artificial suppression of mTORC1 activity during experiments with alcohol led to the fact that the usual in such cases increased addiction to drinking was not formed.

The authors achieved the same effect by using the D1 receptor agonist (SKF-81927) and directly stimulating them: this effect led to an increase in mTORC1 activity, which increased the intensity of mRNA translation in the cell, led to the formation of "hypersensitivity" of the cortical neurons of the nucleus accumbens to dopamine and the consolidation of the corresponding behavior. "The mTORC1–dependent plasticity of neurons containing D1 receptors can serve as a neurophysiological basis for the formation of addiction to alcohol," the scientists emphasize.

They also note that previously similar effects on mTORC1 and D1 receptors were shown in experiments with single use of other drugs, which may demonstrate a very broad role of these proteins in the formation of addictions.

Portal "Eternal youth" http://vechnayamolodost.ru 26.02.2015