Glutamate Receptors in Excessive Ethanol Drinking

慢性乙醇暴露已被证明增加小鼠和大鼠脑中的NMDA受体和受体亚单位蛋白的水平。海马NMDA受体的增加被认为与乙醇戒断发作的发生有关，也可能与认知的变化以及乙醇的强化作用有关。在杏仁核中，慢性乙醇和戒断诱导的NMDA受体功能增加可能与乙醇戒断的焦虑作用有关，而有证据表明，延髓核中NMDA受体功能的改变可能与乙醇强化的变化有关。然而，在慢性乙醇暴露期间和在一段时间内的戒断过程中，杏仁核和杏仁核中的NMDA受体的变化还没有被检查。此外，很少有人注意到乙醇诱导的非NMDA（AMPA）谷氨酸受体的变化。NMDA和/或非NMDA的长期适应性变化 谷氨酸受体可能不仅涉及受体亚单位蛋白水平的增加，而且涉及受体的细胞表面表达和/或细胞定位的改变。我们建议评估这些适应性的NMDA和非NMDA谷氨酸受体的慢性乙醇治疗和戒断范式，产生酒精剥夺效应。这种受体变化（例如，与学习、焦虑发生或乙醇强化相关）可能 有助于在该模型中观察到的乙醇消耗的增加。使用生物化学和免疫组织化学技术，在目标1和2中，我们将研究由印第安纳州动物中心提供的，经过反复饮酒和剥夺循环的P和HAD大鼠脑中谷氨酸受体水平、突触定位和细胞表面表达的适应。随着模型的完善，我们还将研究由斯克里普斯诊所提供的大鼠大脑中的谷氨酸受体适应性，据报道，这种适应性具有更长的酒精剥夺效应。这些研究将允许在目标3中更详细地调查导致与酒精剥夺效应相关的NMDA和/或AMPA受体特性变化的分子机制。

Chronic ethanol exposure has been shown to increase NMDA receptors and the levels of receptor subunit proteins in mouse and rat brain. The increase in hippocampal NMDA receptors has been suggested to be related to the occurrence of ethanol withdrawal seizures, and could also be related to changes in cognition, as well as in the reinforcing effects of ethanol. In the amygdala, chronic ethanol and withdrawal-induced increases in NMDA receptor function may be associated with the anxiogenic effect of ethanol withdrawal, while evidence suggests that altered NMDA receptor function in the nucleus accumbens could be associated with changes in ethanol reinforcement. However, changes in NMDA receptors in the amygdala and nucleus accumbens during chronic ethanol exposure and during a period of withdrawal have not been examined. Furthermore, little attention has been given to ethanol-induced alterations in non-NMDA (AMPA) glutamate receptors. Long-term adaptive changes in NMDA and/or non-NMDA glutamate receptors may involve not only increases in receptor subunit protein levels, but also altered cell surface expression and/or cellular localization of the receptors. We propose to assess these adaptations in NMDA and non-NMDA glutamate receptors following the chronic ethanol treatment and withdrawal paradigm that produces the alcohol deprivation effect. Such receptor changes (e.g., associated with learning, anxiogenesis, or ethanol reinforcement) may contribute to the observed increase in ethanol consumption in this model. Using both biochemical and immunohoistochemical techniques, in Aims 1 and 2 we will investigate adaptations in glutamate receptor levels, synaptic localization and cell surface expression in brains from P and HAD rats that have been taken through repeated cycles of alcohol drinking and deprivation, provided by the Indiana Animal Core. As the models are refined, we will also investigate glutamate receptor adaptations in brains of rats provided by The Scripps Clinic, in which a more prolonged alcohol deprivation effect has been reported. These studies will allow a more detailed investigation in Aim 3 of molecular mechanisms leading to changes in NMDA and/or AMPA receptor properties associated with the alcohol deprivation effect.