Ma M, Shepherd G M
Section of Neurobiology, Yale University, School of Medicine, New Haven, CT 06520, USA.
Proc Natl Acad Sci U S A. 2000 Nov 7;97(23):12869-74. doi: 10.1073/pnas.220301797.
In contrast to rapid progress in the molecular biology of olfaction, there are few physiological data to characterize the odor response properties of different populations of olfactory receptor neurons (ORNs) and their spatial distributions across the epithelium, which is essential for understanding the coding mechanisms underlying odor discrimination and recognition. We have tested the hypothesis that the ORNs are arranged in a functional mosaic, using an intact epithelial preparation from the mouse, in which odor responses of many ORNs in situ can be monitored simultaneously with calcium imaging techniques. ORNs responding to a given odor were widely distributed across epithelium and intermingled with ORNs responding to other odors. Tight clusters of ORNs responding to the same odor were observed. For a given odor, more ORNs were recruited when the concentration was increased. ORNs were able to distinguish between pairs of enantiomers by showing distinct but somewhat overlapping patterns. The results provide evidence regarding the response spectra of ORNs in situ, supporting the combinatorial coding of odor quality and intensity by different ORN subsets.
与嗅觉分子生物学的快速进展形成对比的是，几乎没有生理学数据来描述不同群体的嗅觉受体神经元（ORN）的气味反应特性及其在上皮组织中的空间分布，而这对于理解气味辨别和识别背后的编码机制至关重要。我们使用来自小鼠的完整上皮制剂，检验了ORN以功能镶嵌形式排列的假说，在该制剂中，可以通过钙成像技术同时监测许多原位ORN的气味反应。对给定气味作出反应的ORN广泛分布于上皮组织中，并与对其他气味作出反应的ORN相互交织。观察到对相同气味作出反应的ORN紧密聚集。对于给定气味，当浓度增加时会募集更多的ORN。ORN能够通过显示不同但略有重叠的模式来区分对映体对。这些结果提供了关于原位ORN反应谱的证据，支持了不同ORN亚群对气味质量和强度的组合编码。
