Neuroepigenetics mind map continued (Skepticism of neuroepigenetics ( …
Neuroepigenetics mind map continued
Skepticism of neuroepigenetics
Rats who were nurtured did not have theur corticol receptor gene DNA methylation go up, rather for non nurtured mice it went down.
This was the same for the mice and arginine vasopressin.
Epigenetic changes only occured on some genes in some areas of the brain, but not others.
Different areas of the brain are separate and respond to different stimuli so this is not a problem
Epigenetics changes were very small.
Scientists are worried about correlation does not equal causation
Active DNA methylation is due to an OH group being added to 5-methylcytosine, having the same effect as demethylation.
Other type of DNA methylation is the fading out of methylation as DNA is replicated and methylation does not occur on the new strand.
Because of the addition of the OH group forming 5-hydroxymethylcytosine, MeCp2, a methylation reeader, did not recognise this is a methylated DNA.
It as only been with very recent techniques that 5-hydorxymethylcytosine has been detected so it is possible that the detected lowered methylation levels are to do with active methylation.
The cortex and hippocampus are involved in memory storage.
The cortex is for long storage memories and the hippocampus is where memories are temporarily processed, before being deleted or transferred to the cortex.
Evolutionarily, these makes sense as remembering everything you have ever done is too much but having onlly short term memory is not good too.
Experiments on memory are difficult because not enough is known abou tht ebrain.
Memory involves long term changes in gene expression and the connections between neurones so epigenetics may explain this.
DNA methylation and histone modifications in mammals are important in learning and in memory.
DNMT3A and DNMT3B are involved in learning and in memory and treating rats with DNMT inhibitors affects the hippocampus and cortex.
In Rubenstein- Taybi syndrome, histone acetyltransferase is a mutated gene. Mental retardation is a common sympton of this disorder and mice with lower levels of histone acetylation in their hippocampus had problems with their memory.
When these mice were given SAHA, an HDAC inhibitor, their memory improved.
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Addiction could be treated with epigenetic therapies
In mouse studies it was found that drug addcited mice had changes in their DNA methylation patterns and therefore how their methylation was read by MeCp2- these long lasting gene expression underpin addiction.
The molecular pathway that this happens by is not very well understood.
Epigenetic drugs used to treat children would be ideal but could be ethically debated.
Trials would also need to go on for decades to see the effect of drugs throughout their children's lives and would not be profitable for drug companies.
It was found in mice that Grb10 (a gene) when switched off makes mice aggressive (like an aggressive drunk) but when this is switched on again, mice become less overly aggressive