De vraag die zich stelt, is hoe die omgevingsfactoren precies inwerken op het DNA en de genen. Een onlangs verschenen studie geeft ietsje meer duidelijkheid daarover. Onderzoekers gingen na wat er gebeurt met het DNA van muizen als ze 30 min. bloot staan aan stress (zoals dit bv. zou gebeuren bij een post-traumatische stressstoornis), welke invloed dit had op de genexpressie en hoe een antidepressivum zoals Prozac daarin tussenkomt:
uit: Science Daily, Rockefeller University (2009, December 31). Acute stress leaves epigenetic marks on the hippocampus.In trying to explain psychiatric disorders, genes simply cannot tell the whole story. The real answers are in the interaction of genes and the environment. Post-traumatic stress disorder requires some trauma, for instance, and people, for the most part, aren't born depressed. Now research has revealed one mechanism by which a stressful experience changes the way that genes are expressed in the rat brain. The discovery of "epigenetic" regulation of genes in the brain is helping change the way scientists think about psychiatric disorders and could open new avenues to treatment.
...
found that a single 30-minute episode of acute stress causes a rapid chemical change in DNA packaging proteins called histones in the rat hippocampus, which is a brain region known to be especially susceptible to the effects of stress in both rodents and humans. The chemical change Hunter examined, called methylation, can either increase or decrease the expression of genes that are packaged by the histones, depending on the location of the methylation.
...
However, when he treated the rats with fluoxetine, the generic form of the popular antidepressant Prozac, he reversed some methylation effects associated with chronic stress. It's becoming increasingly evident, Hunter says, that the epigenetic changes like the methyl marks he observed and others, such as acetylation and phosphorylation, could play a significant role in the brain's response to stress and the treatment of stress related diseases, such as post-traumatic stress disorder...
abstract van de studie zelf: Hunter et al. Regulation of hippocampal H3 histone methylation by acute and chronic stressProceedings of the National Academy of Sciences, 2009; 106 (49): 20912
Dido
