OLFACTORY RECEPTOR NEURONS

近年来的研究表明，嗅觉受体神经元的组织中有很强的空间成分。多神经元嗅电图（EOG）记录系统地分布在大鼠嗅觉上皮上，显示了对具有特定化学结构的气味的选择性反应。对极性和非极性气味反应不同的上皮区域表达不同的嗅觉受体基因亚群，这些区域的orn向嗅球的不同部位发送轴突。这表明嗅觉处理过程中存在空间因素。个体ORN群体或受体蛋白群体的行为尚未被广泛调查，尽管已经研究了一小部分。我们将使用EOG记录的结果作为指导，研究单个orn的性质。最终目标是找到化学结构决定气味质量的原理。例如，假设背侧上皮中的大多数orn对极性分子更敏感，而腹侧上皮中的orn对饱和碳氢化合物更敏感。由于有证据表明受体机制存在多样性，因此将对orn中抑制相互作用的可能性进行研究。该研究将在完整的大鼠嗅上皮中进行，以保留空间关系和周围组织中发生的过程。主要的技术将是细胞外单单位记录，尽管细胞内穿透可以用来验证关于抑制作用的结论，或者证实非常广泛的反应光谱是由orn而不是多细胞记录产生的。这项研究应该能更好地理解嗅球输入的空间组织。这些数据可能最终有助于理解这种感觉系统的基本功能，这在社会和饮食行为中很重要。

Recent advances have suggested a strong spatial component in the organization of olfactory receptor neurons (ORNs). Multineuron electroolfactogram (EOG) recordings spaced systematically across the rat olfactory epithelium show selective responses to odorants with certain chemical structures. The regions of the epithelium responding differently to polar and nonpolar odorants express different subgroups of olfactory receptor genes and ORNs of these regions send axons to different parts of the olfactory bulb. This suggests a spatial factor in olfactory processing. The behavior of individual ORN populations or of receptor protein populations has not been extensively surveyed, although a small number have been studied. We will use findings from our EOG recordings as a guide to investigate the properties of individual ORNs. The ultimate goal is to find principles by which chemical structure determines odor quality. For example, it is hypothesized that most ORNs in the dorsal epithelium will be more responsive to polar molecules, while those in the ventral epithelium will be more responsive to saturated hydrocarbons. Because of evidence suggesting diversity in receptor mechanisms, the possibility of inhibitory interactions in ORNs will be studied. The studies will be done in the intact rat olfactory epithelium to preserve both spatial relationships and the processes 'occurring in the surrounding tissue. The primary technique will be extracellular single unit recording, although intracellular penetrations may be used to validate conclusions about inhibitory actions or confirm that very broad response spectra result from ORNs rather than multicellular recordings. The research should provide a greater understanding of the spatial organization of inputs to the olfactory bulb. The data may ultimately aid in the understanding of the basic functioning of this sensory system, which is important in social and alimentary behaviors.