Scientists from the U.S. have shown that people suffering from clinical depression, jet lag occurs at the cellular level, according to the portal Medical Xpress. For details of work carried out by researchers from the University of Michigan Medical School, presented in Proceedings of the National Academy of Sciences.
Failure of circadian rhythms is one of the symptoms observed in major depressive disorder, also known as clinical depression. This condition is characterized by several features, including sleep disturbance and appetite, lack of mood, loss of energy, and suicidal ideas.
Previously, scientists have shown circadian rhythms of gene expression in animals and several peripheral tissues of the human body. Now a group of researchers from the University of Michigan, led by Huda Akil (Huda Akil) clearly decided to prove that the so to say "schedule" of gene expression in depression and even broken in the tissues of the brain. To this end, they have studied circadian rhythms in cells of eighty-nine bodies that have been donated for research.
In his work doctors have used brain 55 patients who had never in his lifetime from depression or other mental illnesses character had not suffered and bodies of 34 patients with clinical depression. Researchers collected data containing information about 12,000 transcripts (mRNA), which were prepared from the different cell areas of the brain. Among them were such "circadian" genes as BMAL1 (ARNTL), PER1-2-3, NR1D1 (REV-ERBa), DBP, BHLHE40 (DEC1) and BHLHE41 (DEC2).
Akil and his colleagues managed by the activity of certain genes in the bodies of the respondents in the control group to determine the precise time of death. Thus, almost all biological clock brain cells of patients in this group have worked remarkably well. A very different picture was observed by experts in the bodies of people with depression: they have been marked by a failure of circadian rhythms and expression of the "night" of genes in the afternoon. Furthermore, a study found out circadian rhythms of activity many other previously unknown genes in different brain regions.
"We found that many genes with a specific 24-hour cycle in healthy people, there is no synchronization with standard daylight hours in depressed patients. The impression that they died in a different time zone, "- said one of the authors of the work. Time jitter can occur in the form of violation by any individual connection between circadian genes, scientists believe.