COBRE: UVM BIOL PROJ 1: CHLORIDE HOMEOSTASIS IN OLFACTORY NEURONS AGING

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。无法察觉气味是一个非常现实的障碍。嗅觉减弱在老年人中很常见，可能会导致营养不良。许多医学问题，如囊性纤维化和阿尔茨海默病，都可能导致嗅觉功能障碍。了解嗅觉系统的核心是确定输入，即初级嗅觉神经元(OSN)的功能；这是我们的长期目标。氯离子通量和细胞内氯离子水平对决定嗅觉神经元暴露在气味中的最终结果是极其重要的：它是被刺激还是被抑制？氯离子水平起着至关重要的作用，但由于氯离子在信号转导途径中出现的时间较晚，与其他第二信使相比，人们对它的关注较少。我们正在测试一种假设，即氯离子的稳态对嗅觉神经元的功能至关重要，并且改变[氯]i会改变气味反应。进展：MEQ荧光成像实验结果表明，在分离的OSN中存在广泛的[Cl]i，除非细胞受到刺激，否则[Cl]i水平保持不变。抑制NKCC1和KCC2这两个氯转运体中的任何一个都可以改变气味反应，尽管似乎有第三个氯转运体的作用在NKCC1活性降低时观察到。免疫细胞化学显示NKCC1和KCC2定位于纤毛和树突结节上，是气味传递的部位。这些氯转运体是如何被调控的仍不清楚，但[Cl]i在气味转导中发挥着不可或缺的作用，可能决定了气味反应是兴奋的还是抑制的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The inability to detect odors is a very real handicap. A diminished sense of smell, which is quite common in the elderly, can lead to malnutrition. A number of medical problems, such as cystic fibrosis and Alzheimer's disease, can cause olfactory dysfunction. Central to the understanding of the olfactory system is determining how the inputs, the primary olfactory sensory neurons (OSNs) function; this is our long-term goal. Chloride fluxes and intracellular chloride levels are extremely important in determining the ultimate outcome of the exposure of an olfactory neuron to odor: is it stimulated or inhibited? Chloride levels play an essential role, but because Cl- comes in late in the signal transduction pathway, less attention has been focused on it compared to other second messengers. We are testing the hypothesis that Cl- homeostasis is essential to olfactory neuron function and that changing [Cl]i alters odor responses. Progress: Results from MEQ fluorescence imaging experiments indicated that a wide range of [Cl]i exist in isolated OSNs and that [Cl]i levels remain constant unless the cell is stimulated. Inhibition of either of the two Cl transporters, NKCC1 and KCC2 can alter the odor response although there appears to be a 3rd Cl transporter whose effects were observed when NKCC1 activity was decreased. Immunocytochemistry on isolated OSNs showed the NKCC1 and KCC2 are located on the cilia and dentritic knob, the site of odor transduction. How these Cl transporters are regulated remains unclear but [Cl]i plays an integral role in odor transduction and probably determines if an odor response is excitatory or inhibitory.