Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, PA 19107, USA.
Alcohol Clin Exp Res. 2012 Oct;36(10):1688-700. doi: 10.1111/j.1530-0277.2012.01791.x. Epub 2012 Apr 6.
Chronic alcohol exposure produces neuroadaptation, which increases the risk of cellular excitotoxicity and autonomic dysfunction during withdrawal. The temporal progression and regulation of the gene expression that contributes to this physiologic and behavioral phenotype is poorly understood early in the withdrawal period. Further, it is unexplored in the dorsal vagal complex (DVC), a brainstem autonomic regulatory structure.
We use a quantitative polymerase chain reaction platform to precisely and simultaneously measure the expression of 145 neuromodulatory genes in more than 100 rat DVC samples from control, chronically alcohol-exposed, and withdrawn rats. To gain insight into the dynamic progression and regulation of withdrawal, we focus on the expression of a subset of functionally relevant genes during the first 48 hours, when behavioral symptoms are most severe.
In the DVC, expression of this gene subset is essentially normal in chronically alcohol-exposed rats. However, withdrawal results in rapid, large-magnitude expression changes in this group. We observed differential regulation in 86 of the 145 genes measured (59%), some as early as 4 hours into withdrawal. Time series measurements (4, 8, 18, 32, and 48 hours after alcohol removal) revealed dynamic expression responses in immediate early genes, γ-aminobutyric acid type A, ionotropic glutamate, and G-protein coupled receptors and the Ras/Raf signaling pathway. Together, these changes elucidate a complex, temporally coordinated response that involves correlated expression of many functionally related groups. In particular, the expression patterns of Gabra1, Grin2a, Grin3a, and Grik3 were tightly correlated. These receptor subunits share overrepresented transcription factor binding sites for Pax-8 and other transcription factors, suggesting a common regulatory mechanism and a role for these transcription factors in the regulation of neurotransmission within the first 48 hours of alcohol withdrawal.
Expression in this gene set is essentially normal in the alcohol-adapted DVC, but withdrawal results in immediate, large-magnitude, and dynamic changes. These data support both increased research focus on the biological ramifications of alcohol withdrawal and enable novel insights into the dynamic withdrawal expression response in this understudied homeostatic control center.
慢性酒精暴露会产生神经适应，这会增加戒断期间细胞兴奋性毒性和自主功能障碍的风险。在戒断早期，对导致这种生理和行为表型的基因表达的时间进程和调节知之甚少。此外，在脑干自主调节结构背侧迷走复合体（DVC）中，这一情况也尚未得到探索。
我们使用定量聚合酶链反应平台，精确且同时测量 145 种神经调节基因在 100 多个来自对照、慢性酒精暴露和戒断大鼠的大鼠 DVC 样本中的表达。为了深入了解戒断的动态进展和调节，我们专注于这组功能相关基因在行为症状最严重的前 48 小时内的表达。
在 DVC 中，慢性酒精暴露的大鼠中，这组基因的表达基本正常。然而，戒断导致该组中出现快速、大幅度的表达变化。我们观察到在测量的 145 个基因中有 86 个（59%）基因出现差异调节，有些基因在戒断后 4 小时就出现了变化。时间序列测量（酒精去除后 4、8、18、32 和 48 小时）揭示了即时早期基因、γ-氨基丁酸 A 型、离子型谷氨酸和 G 蛋白偶联受体以及 Ras/Raf 信号通路的动态表达反应。这些变化共同阐明了一个复杂的、时间协调的反应，涉及许多功能相关群体的相关性表达。特别是，Gabra1、Grin2a、Grin3a 和 Grik3 的表达模式紧密相关。这些受体亚基共享 Pax-8 和其他转录因子的过度代表转录因子结合位点，表明存在共同的调节机制，这些转录因子在酒精戒断后 48 小时内的神经传递调节中起作用。
在适应酒精的 DVC 中，这组基因的表达基本正常，但戒断后会立即出现大幅度和动态变化。这些数据既支持增加对酒精戒断生物学后果的研究重点，又能为这一研究不足的体内平衡控制中心的动态戒断表达反应提供新的见解。
