Redes Neuronales Plásticas Laboratory, Department of Neurobiología Conductual y Cognitiva Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, México.
J Neurosci. 2013 Jan 23;33(4):1631-9. doi: 10.1523/JNEUROSCI.2916-12.2013.
After spatial exploration in rats, Arc mRNA is expressed in ∼2% of dentate gyrus (DG) granule cells, and this proportion of Arc-positive neurons remains stable for ∼8 h. This long-term presence of Arc mRNA following behavior is not observed in hippocampal CA1 pyramidal cells. We report here that in rats ∼50% of granule cells with cytoplasmic Arc mRNA, induced some hours previously during exploration, also show Arc expression in the nucleus. This suggests that recent transcription can occur long after the exploration behavior that elicited it. To confirm that the delayed nuclear Arc expression was indeed recent transcription, Actinomycin D was administered immediately after exploration. This treatment resulted in inhibition of recent Arc expression both when evaluated shortly after exploratory behavior as well as after longer time intervals. Together, these data demonstrate a unique kinetic profile for Arc transcription in hippocampal granule neurons following behavior that is not observed in other cell types. Among a number of possibilities, this sustained transcription may provide a mechanism that ensures that the synaptic connection weights in the sparse population of granule cells recruited during a given behavioral event are able to be modified.
在大鼠的空间探索之后，Arc mRNA 在大约 2%的齿状回（DG）颗粒细胞中表达，并且这种 Arc 阳性神经元的比例在大约 8 小时内保持稳定。这种行为后 Arc mRNA 的长期存在在海马 CA1 锥体神经元中观察不到。我们在这里报告，在大鼠中，在探索过程中几个小时前诱导的具有细胞质 Arc mRNA 的大约 50%的颗粒细胞也在核中显示 Arc 表达。这表明最近的转录可以在引发它的探索行为之后很久发生。为了确认延迟的核 Arc 表达确实是最近的转录，在探索后立即给予 Actinomycin D。这种处理导致在探索行为后不久以及更长时间间隔评估时，最近的 Arc 表达均受到抑制。总之，这些数据表明，在行为后，海马颗粒神经元中的 Arc 转录具有独特的动力学特征，而在其他细胞类型中观察不到这种特征。在许多可能性中，这种持续的转录可能提供了一种机制，确保在特定行为事件中募集的稀疏颗粒细胞群体中的突触连接权重能够被修改。
