Physiological analysis of retronasal olfaction

描述(申请人提供)：气味空气可在吸气或嗅探过程中通过外鼻孔垂直进入鼻子。它也可以在呼气或吞咽和咀嚼运动时逆行进入鼻腔。人类和一些动物的研究表明，正鼻和后鼻路径之间的感觉诱发存在差异。鼻后嗅觉在味觉的功能上是重要的，在衰老和疾病中很可能有助于味觉鉴赏的改变。鼻后嗅觉也可能对食物中的脂肪含量有不同程度的敏感，从而导致与肥胖问题密切相关的食物偏好。文献中的一些证据表明，气味的物理化学性质可能解释了正鼻刺激和鼻后刺激之间知觉差异的部分原因，尽管三叉神经感觉和/或运动中心的协调活动也很可能起作用。鼻腔中的空气流量与气味的物理化学性质(包括粘膜的溶解性和空气中的扩散性)相互作用。我们记录的大鼠在正鼻和鼻后刺激时的电嗅觉图显示，鼻后通路对极性(亲水)气味的反应大大降低，而对非极性(疏水)气味的反应保持不变。这项研究将利用来自嗅球的电嗅觉记录和记录来研究气味特性如何与正鼻和后鼻侧的气流参数相互作用。我们将研究这种制剂是否可以用作鼻后嗅觉的模型，并将特别包括一系列风味气味物质。大鼠的鼻后输入似乎优先激活嗅觉上皮的侧隐窝。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导致球内非常不同的作用模式，这取决于呈现的途径。

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.