In mice, of which 42 days were fed with alcohol, and then forced to abandon it, the brake somatostatinoma excitability of neurons in the prefrontal cortex increased, and in the ventral bed nucleus of the terminal strips has decreased. In the result, during the test, the despair of the neurons of the first zone inhibited, and the second is activated, and the animals developed depressive behavior. Interestingly, all these patterns of females was more pronounced than in males. The authors of the work published in the journal Frontiers in Behavioral Neuroscience, suggest that this fact may explain the increased vulnerability of women to alcohol withdrawal syndrome.
Alcoholism and withdrawal syndrome is closely associated with anxiety-depressive symptoms, this is evident not only in humans but also in model animals (e.g., mice). The use of antidepressants reduces both the consumption of alcohol, and depressive behavior of mice, but the mechanisms of when alcoholism and psychiatric disorders is unknown.
With depression and neuropsychiatric diseases such as obsessive compulsive disorder or schizophrenia, bind to a subpopulation of inhibitory neurons that release the neuropeptide somatostatin. Weak activity of these cells observed in MDD, and its enhancement using genetic tools reduces anxious behavior in mice. But part somatostatinergic neurons in the development of depressive symptoms during abstinence syndrome are still not explored.
Scientists from the University of Pennsylvania under the leadership of Nicole Crowley (Crowley Nicole) investigated the role somatostatinoma of neurons in different areas of the brain during withdrawal syndrome. For this 21, the mice for 42 days were placed in cages two bottles: one with water, another with alcohol, the concentration of which is gradually increased from three to ten per cent (with 22 control mice both bottles were filled with water). Then the bottle of alcohol was removed, causing the animal abstinence. After a forced abstinence from alcohol weekly, animals were tested in several standard tests of anxious behavior.
During the first six weeks of the experiment, females consumed on average significantly more alcohol than males; all mice preferred the solution of alcohol water. In tests for disturbing behavior results in mice with enforced abstinence from alcohol did not differ from the control. But the animals showed symptoms of depression: males in the test of Porsolt to despair (the animal is placed in a cylinder of water from which they cannot escape, and watch to see how long they will continue to flounder) and mice of both sexes in the test of preference for sweet or ordinary water (animals of the experimental group refused from sweet water).
To understand the neurons in any region of the brain active in depressive behavior, the researchers analyzed the expression of the gene c-fos, which is associated with excitation of nerve cells, after the test of Porsolt. In the prefrontal cortex of females with forced abstinence from alcohol, the expression of c-fos was lower than in the control group (p < 0.05) and in males (p < 0.001), but somatostatinoma neurons are activated equally in all animals. Then the researchers measured the electrophysiological characteristics of these cells by the method of local fixation potential. It turned out that somatostatinoma neurons females with forced abstinence from alcohol more excitable than the control mice.