MOLECULAR MECHANISMS OF GLUTAMATE RECEPTOR CHANNELS

这项研究的长期目标是通过 大脑中的哪些突触会因活动和环境而改变 刺激物。我们关注的是一种特定类型的突触受体--NMDA 谷氨酸受体的一类-在长期的 突触功能的变化，细胞死亡的调节，以及 神经元网络中模式活动的产生。这些过程 要求NMDA受体允许适量的钙 离子穿过它的孔进入神经元，并被 适当范围的膜上的胞外镁离子 电势和浓度。因此，为了理解 突触可塑性的分子基础，我们必须了解 决定二价阳离子渗透性和阻断性的机制 NMDA受体。我们将使用重组DNA技术来证明 受体蛋白的突变，然后研究改变的功能 使用单通道贴片检测突变受体(在卵母细胞中表达) 钳制方法。我们将研究毛孔残留物是如何 受体的亚基组成，决定与钙的亲和力 如果通道电导由静电调节，则为镁 机制，以及次导电平被 已生成。我们还将调查亚基组成(类型和 拷贝数)通过研究次导模式获得受体 在由不同混合物组成的受体中明显的状态 野生型和突变型亚基。对分子的理解 NMDA受体通道的运行机制将提供洞察力 成为发育、退行性和其他疾病的基础 神经系统。

The long term goal of this research is to understand the mechanisms by which synapses in the brain are changed by activity and environmental stimuli. We focus on a specific type of synaptic receptor - the NMDA class of glutamate receptor - that plays an important role in long-term changes in synaptic function, the regulation of cell-death, and the generation of patterned activity in neuronal networks. These processes require that the NMDA receptors allow the appropriate amount of calcium ion to pass through its pore and enter the neuron, and be blocked by extracellular magnesium ion over an appropriate range of membrane potentials and concentrations. Thus, in order to understand the molecular bases of synaptic plasticity, we must understand the mechanisms that determine the divalent cation permeability and block of NMDA receptors. We will use recombinant DNA technology to make point mutations in the receptor protein, and then study the altered functions of mutant receptors (expressed in oocytes) using single-channel patch clamp methods. We will investigate how the pore residues, and the subunit composition of the receptor, determine the affinity for calcium and magnesium, if the channel conductance is regulated by electrostatic mechanisms, and the mechanisms by which subconductance levels are generated. We will also investigate the subunit composition (type and copy number) of receptors by studying the patterns of subconductance states that are apparent in receptors composed of different mixtures of wild type and mutant subunits. An understanding of the molecular mechanisms of operation of NMDA receptors channels will provide insight into the basis of developmental, degenerative and other diseases of the nervous system.