Physiological analysis of retronasal olfaction

描述（由申请人提供）：吸气或嗅吸时，有气味的空气可通过外鼻孔垂直进入鼻腔。它也可以在呼气或吞咽和咀嚼运动时从鼻后进入。人类和一些动物的研究表明，在正鼻通道和后鼻通道之间所引起的感觉是不同的。后鼻嗅觉在味觉上具有重要的功能，并可能对衰老和疾病中味觉的变化有很大的影响。鼻后嗅觉也可能对食物中的脂肪含量有不同的敏感性，从而导致与肥胖问题密切相关的食物偏好。来自文献的一些证据表明，气味剂的物理化学特性可能解释了正鼻和后鼻刺激之间感知差异的一些原因，尽管很可能三叉神经感觉和/或运动中心的协调活动也可能起作用。鼻子中的气流速率与气味剂的理化性质（包括在空气中的粘膜溶解度和扩散性）相互作用。我们在正鼻和后鼻刺激下的大鼠嗅电图记录表明，后鼻通路对极性（亲水）气味的反应大大减少，而对非极性（疏水）气味的反应保持不变。本研究将利用嗅电图记录和嗅球记录来研究气味特性如何与正鼻和反鼻气流参数相互作用。我们将研究这种制剂是否可以用作鼻后嗅觉模型，并将具体包括一系列风味气味剂。大鼠的后鼻输入似乎优先激活嗅上皮的外侧隐窝。这也可能为研究嗅球生理学提供一个有用的工具，因为一个单一的刺激可以根据呈现的途径导致嗅球中非常不同的行为模式。

DESCRIPTION (provided by applicant): Odorized air can enter the nose orthonasally through the external nares during inspiration or during sniffing. It can also enter retronasally during expiration or with swallowing and chewing movements. Human and some animal studies have indicated that there are differences in the sensations evoked between the orthonasal and retronasal routes. Retronasal olfaction is functionally important in appreciation of flavor and could well contribute to changes in flavor appreciation in aging and disease. Retronasal olfaction may also be differentially sensitive to the fat content of food thus contributing to food preferences that are very relevant to the issue of obesity. Some evidence from the literature suggests that physico-chemical properties of odorants may account for some of the differences in perception between orthonasal and retronasal stimulation, although very likely trigeminal sensation and/or coordinated activity in motor centers may also contribute. Air flow rate in the nose interacts with physicochemical properties of odorants (including mucosal solubility and diffusibility in air). Our recordings of rat electroolfactograms during orthonasal and retronasal stimulation show that the retronasal route gives a greatly reduced response for polar (hydrophilic) odorants with preserved responses to non-polar (hydrophobic) odorants. This investigation will utilize electroolfactogram recordings and recordings from the olfactory bulb to study how odorant properties interact with air flow parameters both orthonasally and retronasally. We will investigate whether this preparation can be used as a model of retronasal olfaction and will specifically include a range of flavor odorants. Retronasal inputs in the rat seem to preferentially activate the lateral recesses of the olfactory epithelium. This may also provide a useful tool for study of olfactory bulb physiology because a single stimulus can lead to very different patterns of action in the bulb depending on the route of presentation.