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DIET-INDUCED PLASTICITY IN TASTE CELLS MODIFIES FEEDING

饮食引起的味觉细胞可塑性改变了进食

基本信息

批准号：
2733681
负责人：
JOHN I GLENDINNING
金额：
$ 8.62万
依托单位：
BARNARD COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-07-01 至 2000-06-30
项目状态：
已结题

项目摘要

All animals adapt to changing environments. A key feature underlying this adaptation process is sensory plasticity, which encompasses a broad range of phenomena from alterations in responsiveness (habituation and sensitization) to more complex forms of associative learning. This proposal describes experiments that examine diet-induced plasticity in taste cells, and how this plasticity produces gustatory habituation in an important neurobiological model, Manduca sexta caterpillars. This phenomenon is of general interest because experience-induced plasticity is a prevalent, but poorly understood, feature of chemosensory systems, and it provides a tool with which to study the biological basis of a complex behavior: food preference. The focus will be on bitter taste because of its importance in poison detection. Preliminary experiments have demonstrated that two days of dietary exposure to a bitter tastant (caffeine) causes a large decrease in responsiveness (i.e., desensitization) of the bitter-sensitive taste cell (or bitter cell) to caffeine. Further, the desensitization of the bitter cell was associated with gustatory habituation to a diet treated with caffeine. These results were collected with a preparation that enables one to make repeated electrophysiological recordings from single taste cells before and after dietary manipulations make comparisons across individual caterpillars using homologous taste cells, and relate desensitization to feeding behavior in the same animal. Based on these experiments, the following specific aims were devised: (i) to determine whether prolonged exposure to any tastant that stimulates the bitter cell will produce both desensitization and gustatory habituation to that same tastant' (ii) to determine whether desensitization and gustatory habituation to one bitter tastant generalize to other bitter tastants, (iii) to determine whether the desensitization response to different bitter tastants is mediated by a common mechanism, and (iv) to determine whether desensitization is controlled by bitter compounds acting on the taste cells either systemically via the blood, directly in the absence of ingestion, or indirectly through centrifugal neural efferents. It is hoped that the proposed studies will reveal something basic about taste receptor systems that will generalize to humans. Such generalizations could provide new insights into the interaction between diet and food preference in humans, and how this interaction may contribute to eating disorders. A better understanding of the connection between intake of bitter foods and bitter sensitivity could also help explain the high rate of ingestion of toxic household substances by humans.

所有动物都会适应不断变化的环境。这背后的一个关键特征适应过程是感觉可塑性，它涵盖了广泛的范围反应能力改变（习惯和敏化）到更复杂形式的联想学习。这提案描述了检查饮食诱导的可塑性的实验味觉细胞，以及这种可塑性如何产生味觉习惯重要的神经生物学模型，Manduca sexta 毛毛虫。这这种现象受到普遍关注，因为经验引起的可塑性是化学感应系统的一个普遍但知之甚少的特征，以及它提供了一种研究复杂生物基础的工具行为：食物偏好。重点将放在苦味上，因为它在毒物检测中的重要性。初步实验有证明在饮食中接触苦味促味剂两天（咖啡因）导致反应能力大幅下降（即，苦味敏感味觉细胞（或苦味细胞）的脱敏作用咖啡因。此外，苦味细胞的脱敏与对含有咖啡因的饮食产生味觉习惯。这些结果是用一种制剂收集的，使人们能够重复进行单个味觉细胞前后的电生理记录饮食控制对毛毛虫个体进行比较使用同源味觉细胞，并将脱敏与进食联系起来同一种动物的行为。基于这些实验，以下制定了具体目标：(i) 确定是否长期暴露于任何刺激苦味细胞的促味剂都会产生两种物质对同一促味剂的脱敏和味觉习惯'(ii) 确定是否对一种苦味脱敏和味觉习惯促苦味剂推广到其他苦味促味剂，（iii）确定是否对不同促苦味剂的脱敏反应是由一个共同的机制，以及（iv）确定脱敏是否是由作用于味觉细胞的苦味化合物控制在没有摄入的情况下直接通过血液系统地进行，或间接通过离心神经传出。希望拟议的研究将揭示味觉受体系统的一些基本知识这将推广到人类。这种概括可以提供新的深入了解人类饮食和食物偏好之间的相互作用，以及这种相互作用如何导致饮食失调。更好的了解苦味食物的摄入与苦味之间的联系敏感性也有助于解释有毒物质的高摄入率人类的家庭用品。