Immune, Hormonal and Neural Mechanisms of Feeding Behavior

进食行为的免疫、激素和神经机制

• 批准号: RGPIN-2014-05094
• 负责人: Ossenkopp, KlausPeter
• 金额: $ 2.48万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611435
• 关键词: Immune; Hormonal; Neural; Mechanisms; Feeding

All organisms need to solve the problem of obtaining proteins, carbohydrates, fats and other nutrients from their environment without absorbing significant amounts of toxins, as many plants (and animals) produce toxins to protect against herbivory (or predation). Mammals have evolved a number of mechanisms, both physiological and behavioral, that act as defences against the ingestion and absorption of toxins in food or water. In addition to orosensory assessment of food, postingestional effects provide important information about the nutritional and toxic characteristics of the ingested food. We have characterized the effects of high doses of the toxin LiCl on learning mechanisms involved in the toxin defence system and low doses of this toxin, presented in food, on feeding behaviors. We have shown that large doses of the toxin will not only condition strong disgust responses (gaping) in rats when a novel taste is paired with the effects of the toxin, but a novel context also acquires the ability to elicit disgust responses when paired with the toxin. Of interest to us are the neural systems that are mediating the conditioning of disgust reactions to a context and we will use a lesion approach to examine the roles of the vagus nerve, the brainstem chemosensor (area postrema) and the gustatory insular cortex. We have also demonstrated that rats made sick by activating their immune system with a bacterial mimetic, will not show this type of conditioned disgust, either to a taste cue or a context. Of interest here is to determine how activation of the immune system blocks memory formation. When small doses of LiCl are mixed into a food rats will reduce their food intake to keep the toxin level below a certain threshold value, indicating that the rats are able to track ingested toxin levels. We will again be examining the roles of the same neural structures (vagus, area postrema, insular cortex) in this important phenomenon by using a lesion approach. The role of immune system stimulation in this process will also be examined as will putative age (adolescence and adult) and sex differences in this toxin tracking phenomenon. The overall thrust of this project is to characterise the negative side of incentive motivation (nausea and disgust) related to the toxin defence system.

所有生物都需要解决从环境中获取蛋白质、碳水化合物、脂肪和其他营养素而不吸收大量毒素的问题，因为许多植物（和动物）产生毒素以防止食草动物（或捕食）。哺乳动物已经进化出许多生理和行为机制，作为对食物或水中毒素的摄入和吸收的防御。除了对食物的口腔感觉评估外，摄入后效应还提供了有关摄入食物的营养和毒性特征的重要信息。我们的特点的影响，高剂量的毒素氯化锂的学习机制参与毒素防御系统和低剂量的这种毒素，在食物中，喂养行为。我们已经证明，当一种新的味道与毒素的效果配对时，大剂量的毒素不仅会使大鼠产生强烈的厌恶反应（张口），而且当与毒素配对时，一种新的环境也会获得引发厌恶反应的能力。我们感兴趣的是神经系统，介导的条件反射的厌恶反应的背景下，我们将使用病变的方法来检查迷走神经，脑干化学传感器（最后区）和味觉岛叶皮层的作用。我们还证明，通过用细菌模拟物激活免疫系统而生病的大鼠不会表现出这种类型的条件性厌恶，无论是味觉提示还是环境。这里感兴趣的是确定免疫系统的激活如何阻止记忆的形成。当小剂量的氯化锂混合到食物中时，大鼠会减少食物摄入量，以保持毒素水平低于一定的阈值，这表明大鼠能够跟踪摄入的毒素水平。我们将再次检查的作用，相同的神经结构（迷走神经，最后区，岛叶皮层）在这一重要现象中使用的损伤方法。免疫系统刺激在这一过程中的作用也将被检查，因为将推定的年龄（青春期和成人）和性别差异，在这种毒素跟踪现象。该项目的总体目标是描述与毒素防御系统相关的激励动机（恶心和厌恶）的消极面。