Epigenetic regulation of XXXX and Arc gene expression after electroconvulsive stimulation in the @entity35 .

@entity1 @entity308 @entity54389 @entity14923 @entity46093 @entity71278 @entity35 @entity2414 @entity11508
UNASSIGNED: Electroconvulsive therapy (ECT) remains one of the most effective treatments of @entity308 . Unfortunately, some @entity1 report side effects, of which the most prominent are @entity2414 . The immediate early gene Arc plays a critical role in the maintenance phase of long-term potentiation and consolidation of memory in the @entity35 brain. We recently observed increased methylation of the Arc promoter 24h after acute electroconvulsive stimulation (ECS) in @entity35 , which could cause decreased Arc expression and provide an explanation for the observed @entity2414 . In the present study we investigated the methylation and expression changes of Arc at 48h post-ECS and determined the role of de-novo methylation in that process. We initially measured expression of DNA methyltransferases ( @entity14923 and @entity54389 ) and @entity71278 , 4, 8, 16, 24, and 48h after a single ECS. Arc expression was increased approximately 10-fold at 1 and 4h after ECS, and subsequently decreased below sham levels. Four hours after ECS we also observed a significant increase in @entity54389 expression, which was attenuated in a second experiment by the use of DNMT inhibitor @entity11508 ( @entity11508 ). We then investigated Arc gene expression and methylation changes at 48h post-ECS and we found a slightly reduced Arc expression in ECS-treated @entity35 as compared to sham. In animals that received @entity11508 we observed a significant decrease in @entity54389 expression and an increase of Arc expression in both ECS and sham groups. The same tendency for reduced Arc expression after ECS, as compared to sham was observed despite the blocking of DNA methylation with @entity11508 . The DNA methylation as measured by pyrosequencing is decreased 48h post-ECS both in the promoter and intragenic regions as a response to ECS regardless of the treatment with @entity11508 . Overall the results suggest that DNA methylation is involved in regulating Arc expression but is not the causal mechanism responsible for reducing Arc expression after ECS. We speculate that the decrease is caused by ECS-induced @entity46093 upregulation and decreased H3 acetylation at the Arc promoter.
