Sensory information is selectively or non-selectively enhanced and inhibited in the brain, but it remains unclear whether and how this occurs at the most peripheral level. Using in vivo calcium imaging of mouse olfactory bulb and olfactory epithelium in wild-type and mutant animals, we show that odors produce not only excitatory but also inhibitory responses in olfactory sensory neurons (OSNs). Heterologous assays indicate that odorants can act as agonists to some but inverse agonists to other odorant receptors. We also demonstrate that responses to odor mixtures are extensively suppressed or enhanced in OSNs. When high concentrations of odors are mixed, widespread antagonism suppresses the overall response amplitudes and density. In contrast, a mixture of low concentrations of odors often produces synergistic effects and boosts the faint odor inputs. Thus, odor responses are extensively tuned by inhibition, antagonism, and synergy at the most peripheral level, contributing to robust sensory representations.

感觉信息在大脑中被选择性或非选择性地增强和抑制，但是尚不清楚在最末梢水平是否以及如何发生。体内使用小鼠嗅球和嗅上皮在野生型和突变动物的钙成像中，我们显示，气味不仅在嗅觉感觉神经元（OSNs）中产生兴奋性而且是抑制性反应。异源测定表明，加味剂可以对某些加味剂起激动剂的作用，而对其他加味剂受体起反作用。我们还证明，在OSN中，对气味混合物的响应得到了广泛抑制或增强。当混合高浓度的气味时，广泛的拮抗作用会抑制总体响应幅度和密度。相反，低浓度气味的混合物通常会产生协同作用，并增加微弱的气味输入。因此，在最外围的水平上，通过抑制，拮抗和协同作用，气味反应得到了广泛的调节，有助于形成稳健的感官表现。