GABAA R-subunit changes in adolescents by a cytokine/ethanol withdrawal protocol

描述（由申请人提供）：青春期饮酒会增加成年后酗酒的可能性。同样，压力已被证明在持续酗酒方面起着重要作用。在大鼠中，慢性乙醇致敏性戒断性焦虑之前的反复应激。基于应激增加青春期和成年大鼠大脑细胞因子的基础上，对青春期和成年大鼠的初步研究表明，每周重复给药脂多糖（LPS）以增加大脑细胞因子，然后再给药5天（LPS/戒断方案），可使戒断诱导的焦虑增敏，并在戒断后3天增加大脑14-GABA(A)受体亚基。这一研究结果支持了细胞因子参与应激增强乙醇诱导的适应性变化的结论。因此，对青春期大鼠的研究将首先表征LPS/戒断方案期间和之后皮层14个亚基变化的时间过程。随后，将确定14亚基的增加是否伴随着11、15、32和4 GABA(A)受体亚基的变化。为了评估这种适应性变化是否具有区域特异性，这些评估将在大脑的其他区域进行，包括海马体、丘脑和杏仁核。为了检查GABA(A)受体功能，将进行电生理研究，以测试突触和突触外GABA功能的变化是否在LPS/戒断方案后的较长时间内发生。此外，将进行药理学研究，以确定在选定的大脑区域的这些细胞位点上选定的GABA(A)受体亚基。最后，研究将确定阻断由LPS/戒断方案诱导的乙醇戒断性焦虑的致敏是否会阻止GABA(A)受体亚基的适应性变化，并减少突触和突触外部位的电生理变化。后一种策略将通过在酒精暴露前每周注射LPS剂量之前给予阻断这种致敏的药物来防止LPS/戒断方案对乙醇戒断引起的焦虑的行为致敏来实现。本研究将验证以下假设：LPS/戒断方案诱导的青春期大鼠GABA(A)受体功能的持续适应以及突触和突触外部位的功能变化与该方案诱导的戒断诱导焦虑的致敏性相关。收集到的数据应该为理解细胞因子对应激支持的作用提供基础，功能病理学增加了青少年对成年后持续酗酒的易感性。

DESCRIPTION (provided by applicant): Drinking during adolescence enhances the probability of alcoholism upon reaching adulthood. Likewise, stress has been demonstrated to have an important role in sustaining alcohol abuse. In rats, repeated stresses prior to chronic ethanol sensitized withdrawal-induced anxiety. Based upon stress increasing cytokines in brain in adolescent and adult rats, preliminary research in adolescent and adult rats demonstrated that repeated weekly lipopolysaccharide (LPS) dosing to increase cytokines in brain followed by 5 days of ethanol (LPS/withdrawal protocol) sensitized withdrawal- induced anxiety and increased the 14-GABA(A) receptor subunit in brain 3 days after withdrawal. This effort supports the conclusion that cytokines contribute to the action of stress to enhance adaptive change induced by ethanol. Therefore, studies in adolescent rats will first characterize the time course of the 14 subunit change in cortex during and after the LPS/withdrawal protocol. Subsequently, it will be determine if this increase in the 14 subunit is accompanied by changes in 11, 15, 32, & 4 GABA(A) receptor subunits. To assess if this adaptive change has regional specificity, these assessments will be made in other regions of brain including the hippocampus, thalamus, and amygdala. To examine GABA(A) receptor function, electrophysiological studies will be performed to test if changes in synaptic and extrasynaptic GABA function occur for an extended period after the LPS/withdrawal protocol. Additionally, pharmacological studies will be carried out to identify selected GABA(A) receptor subunits at these cellular sites in chosen brain regions. Finally, studies will be undertaken to determine if blocking sensitization of ethanol withdrawal-induced anxiety induced by the LPS/withdrawal protocol will prevent the adaptive change in GABA(A) receptor subunits and diminish electrophysiological changes at synaptic and extrasynaptic sites. This latter strategy will be accomplished by preventing the LPS/withdrawal protocol behavioral sensitization of ethanol withdrawal-induced anxiety by administering drugs that block this sensitization when given prior to each of the weekly LPS doses injected before ethanol exposure. This work will test the hypothesis that the LPS/withdrawal protocol induction of persistent adaptation in GABA(A) receptor function and functional changes at synaptic and extrasynaptic sites in adolescent rats will correlate with the sensitization of withdrawal-induced anxiety induced by this protocol. The data collected should provide a foundation for understanding the role cytokines contribute to stress support of the functional pathology that increases adolescent susceptibility to continued alcohol abuse as adults.