Natural odors are mixtures of volatile chemicals (odorants). Odors are encoded as responses of distinct subsets of the hundreds of odorant receptors and trace amine-associated receptors expressed monogenically by olfactory sensory neurons. This is an elegantly simple mechanism for differentially encoding odors but it is susceptible to complex dose–response relationships and interactions between odorants at receptors, which may help explain olfactory phenomena, such as mixture suppression, synthetic versus elemental odor processing, and poorly predictable perceptual outcomes of new odor mixtures. In this study, in vivo tests in freely behaving mice confirm evidence of a characteristic receptor response pattern consisting of a few receptors with strong responses and a greater number of weakly responding receptors. Odorant receptors responsive to an odor are often unrelated and widely divergent in sequence, even when the odor consists of a single species of odorant. Odorant receptor response patterns to a citrus odor broaden with concentration. Some highly sensitive receptors respond only to a low concentration but others respond in proportion to concentration, a feature that may be critical for concentration-invariant perception. Other tests find evidence of interactions between odorants in vivo. All of the odorant receptor responses to a moderate concentration of the fecal malodor indole are suppressed by a high concentration of the floral odorant, α-ionone. Such suppressive effects are consistent with prior evidence that odorant interactions at individual odorant receptors are common.

中文翻译：

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混合物和浓度对体内气味受体反应模式的影响。


自然气味是挥发性化学物质（气味剂）的混合物。气味被编码为由嗅觉感觉神经元单基因表达的数百种气味受体和微量胺相关受体的不同子集的反应。这是一种非常简单的差异编码气味机制，但它容易受到复杂的剂量反应关系和受体气味剂之间相互作用的影响，这可能有助于解释嗅觉现象，例如混合物抑制、合成与元素气味处理以及难以预测的感知结果新的气味混合物。在这项研究中，对自由行为的小鼠进行的体内测试证实了特征性受体反应模式的证据，该模式由少数具有强反应的受体和大量弱反应的受体组成。即使气味由单一种类的气味剂组成，对气味作出反应的气味受体通常是不相关的并且在序列上有很大差异。气味受体对柑橘气味的反应模式随着浓度的增加而变宽。一些高度敏感的受体仅对低浓度做出反应，但其他受体的反应与浓度成比例，这一特征对于浓度不变的感知可能至关重要。其他测试发现了体内气味剂之间相互作用的证据。所有气味受体对中等浓度粪便恶臭吲哚的反应都会被高浓度花香剂 α-紫罗兰酮抑制。这种抑制作用与先前的证据一致，即个体气味受体上的气味相互作用是常见的。