Regulation of VTA dopamine neurons by AMP kinase

项目总结摘要： 腹侧被盖区(VTA)神经元释放多巴胺有助于学习目标导向行为和 调节大多数滥用药物的愉悦方面。了解VTA神经元的兴奋性如何 是由突触输入调节的，如果要理解多巴胺是如何 释放受到控制。5‘-腺苷一磷酸(AMP)激活的蛋白激酶(AMPK)是一种 调节细胞新陈代谢的酶。在外周组织中，AMPK激活生化途径， 在减少能源消耗的同时增加能源生产。虽然在大脑中广泛表达，但它的功能 在中枢神经元中的作用在很大程度上是未知的。我们实验室的初步数据表明，AMPK的激活剂可以增强 ATP敏感性K+(K-ATP)通道引起的超极化电流，降低了细胞的脱敏 多巴胺D2自身受体，并抑制兴奋性突触传递在VTA神经元的影响。这个 我们提出的研究的最重要的假设是AMPK的激活增强了对 VTA神经元。斑片吸管将被用来记录单个VTA神经元的全细胞电流和电位 大鼠中脑切片。Western免疫印迹将被用来量化磷酸化和 在有无AMPK存在和不存在的情况下孵育的中脑片中非磷酸化AMPK 激活剂和/或抑制剂。目的#1研究AMPK激动剂对K-受体激动剂诱发电流的影响。 三磷酸腺苷开放剂二氮卓。目标2将研究第二信使系统并识别递质受体 这介导了AMPK激活剂减少多巴胺D2自身受体脱敏的能力。目标#3将 研究AMPK抑制谷氨酸介导的突触传递的机制和作用部位 在VTA里。目标#4将描述AMPK激活抑制VTA内突发放电的机制 多巴胺神经元。这些研究的结果可能会为治疗提供新的药理学策略。 多巴胺依赖型障碍。

Project summary abstract: Dopamine release from ventral tegmental area (VTA) neurons assists in learning goal-oriented behaviors and mediates the pleasurable aspects of most drugs of abuse. Understanding how the excitability of VTA neurons is regulated by synaptic inputs and membrane properties is crucial if one is to understand how dopamine release is controlled. 5'-Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a master enzyme that regulates cellular metabolism. In peripheral tissues, AMPK activates biochemical pathways that increase energy production while reducing energy expenditure. Although widely expressed in brain, its function in central neurons is largely unknown. Preliminary data from our lab suggest that activators of AMPK potentiate the hyperpolarizing current evoked by ATP-sensitive K+ (K-ATP) channels, reduce the desensitization of dopamine D2 autoreceptors, and inhibit the influence of excitatory synaptic transmission in VTA neurons. The over-arching hypothesis of our proposed studies is that AMPK activation augments inhibitory influences on VTA neurons. Patch pipettes will be used to record whole-cell currents and potentials in single VTA neurons in slices of rat midbrain. Western immunoblot will be used to quantify levels of phosphorylated and unphosphorylated AMPK in midbrain slices that have been incubated in the presence and absence of AMPK activators and/or inhibitors. Aim #1 will characterize the effect of AMPK activators on currents evoked by the K- ATP opener diazoxide. Aim #2 will investigate second messenger systems and identify transmitter receptors that mediate the ability of AMPK activators to reduce dopamine D2 autoreceptor desensitization. Aim #3 will investigate mechanisms and sites of action by which AMPK inhibits glutamate-mediated synaptic transmission in the VTA. Aim #4 will characterize mechanisms by which AMPK activation inhibits burst firing in VTA dopamine neurons. Results of these studies may suggest new pharmacological strategies for treating dopamine-dependent disorders.