ETHANOL ACTION ON BRAIN ACIDIC PHOSPHOLIPIDS

先前的研究提供了证据表明长期摄入酒精会导致 与突触内酸性磷脂水平升高有关 膜。已知酸性磷脂(PS、PA、PI和聚PI) 膜蛋白因其阴离子而发挥特殊作用 属性。聚磷脂酰肌醇(PIP和PIP2)具有特殊的性质 由于它们直接参与信号转导而引起的兴趣 路径。使用体内标记方案，我们的实验室已经获得了 多聚PI在大鼠和小鼠脑内的周转受到影响的证据 急性和慢性乙醇注射。此外，对 观察急性乙醇对PolyPI途径的抑制作用 在小鼠长期服用乙醇后。因此，具体目标是 #1是进一步检查内在因素(例如持续时间和方式 乙醇管理)导致了对此的耐受性的发展 信号事件。 PI和PIP激酶是信号通路中的重要酶，因为 它们为受体介导的G蛋白提供底物(PIP2) 偶联磷脂酶C反应。大鼠脑的初步研究 突触质膜显示PIP激酶对 乙醇在体外比PI激活剂更有效。因此，具体目标2将包括 实验研究乙醇对人体健康的作用机制 这两个激酶，并检验慢性乙醇 暴露会导致这些激酶的适应性变化。突触血浆 膜将被用来测试(A)乙醇和脂肪族的影响 乙醇存在和不存在时对PI和PIP激酶活性的影响 外源底物，(B)酶活性的内在变化 在长期服用乙醇后出现在脑膜中，(C) 乙醇、酸性磷脂和乙醇的相互作用 纯化的PIP激酶上的阳离子两亲性化合物，以及(D) 乙醇对磷酸单酯酶活性的影响。为了 乙醇对PI和PIP激酶的作用与其多聚体代谢的关系 PI周期，特殊的AIMS#3将使用星形胶质细胞系作为模型 系统。酒精暴露对这些酶的影响将是相关的。 这些细胞对激动剂(如缓激肽)的反应能力 已知通过Poly-PI途径传递信号。信息 从这个项目中获得的信息将对理解 耐受性发展的潜在机制，并可能具有 靶向药物或治疗方案的潜力，以缓解 与戒酒有关的有害影响。

Previous studies provided evidence that chronic ethanol ingestion leads to an increase in levels of the acidic phospholipids in synaptic membranes. Acidic phospholipids (PS, PA, PI, and poly-PI) are known to exert specific effects on membrane proteins due to their anionic properties. The polyphosphoinositides (PIP and PIP2) are of special interest due to their direct involvement in the signal transduction pathway. Using in vivo labeling protocols, our laboratory has obtained evidence that poly-PI turnover in rat and mouse brain was affected by acute and chronic ethanol administration. Furthermore, tolerance to the inhibitory effect of acute ethanol on the poly-PI pathway was observed in mice after chronic ethanol administration. Therefore, specific aim #1 is to further examine the intrinsic factors (e.g. duration and mode of ethanol administration) leading to development of tolerance in this signaling event. PI and PIP kinases are important enzymes in the signaling pathway since they provide the substrate (PIP2) for the receptor-mediated and G-protein coupled phospholipase C reaction. Preliminary studies with rat brain synaptic plasma membranes indicate that PIP kinase is more sensitive to ethanol in vitro than PI kinase. Therefore, specific aim #2 will include experiments to examine the mechanism underlying the action of ethanol on these two kinases and to test the hypothesis that chronic ethanol exposure results in an adaptive change in these kinases. Synaptic plasma membranes will be used to test for (a) effects of ethanol and aliphatic alcohols on the PI and PIP kinase activity in the presence and absence of exogenous substrates, (b) intrinsic changes in enzyme activity occurring in brain membranes after chronic ethanol administration, (c) interaction between the effects of ethanol, acidic phospholipids and cationic amphipathic compounds on purified PIP kinase, and (d) the effects of ethanol on the phosphomonoesterase activity. In order to relate ethanol's action on PI and PIP kinases to metabolism of the poly- PI cycle, specific aims #3 will use an astrocyte cell line as a model system. The effect of ethanol exposure on these enzymes will be related to the ability of these cells to respond to agonists (e.g. bradykinin) known to transduce signals through the poly-PI pathway. Information obtained from this project will be important in understanding the mechanism underlying the development of tolerance and may have the potential of targeting drugs or treatment protocols to alleviate the detrimental effects associated with alcohol withdrawal.