VOLTAGE CLAMP PROBE OF TASTE RESPONSES IN DEVELOPMENT

正在开发的味觉响应电压钳探针

• 批准号: 6516140
• 负责人: John A Desimone
• 金额: $ 31.02万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6516140
• 关键词: acidity /alkalinity; age difference; apical membrane; basolateral membrane; bioimaging /biomedical imaging; developmental neurobiology; dietary potassium; dietary sodium; electrophysiology; fluorescent dye /probe; food flavor; ion transport; laboratory rat; membrane potentials; microelectrodes; nutrition related tag; taste; taste buds; taste threshold; tongue; voltage /patch clamp

DESCRIPTION: (Adapted from the Applicant's Abstract). Taste stimuli interact with taste-sensitive cells in taste buds, the majority of which are located in papillae on the upper surface of the tongue. Substances with appetitive tastes (e.g., sweet stimuli) are normally ingested; those that are aversive (e.g., bitter stimuli) are rejected, although these tendencies can be modified by experience. Some of the changes that occur in taste preferences appear to be age related and this has been well-documented in rodent models. Changes in taste sensitivity to sodium chloride with early postnatal development are especially clear. Some sensitivity to sodium chloride is present at birth, but much develops later, particularly when the animals are weaned. There are two modes of salt-taste sensing, which appear to reside in different regions of the taste bud. One sensor, on the apical microvilli of taste cells, makes direct contact with the mouth fluid. The other is sequestered on the basolateral membrane of the cells so that some stimuli must diffuse through the tight junctions separating the apical and basolateral domains of the cells to reach the receptor sites. Data suggest that access to these basolateral sites can be blocked by calcium, and that the tight junction permeability to taste stimuli changes during development. In vivo recordings of taste nerve responses, with the receptive field under voltage-clamp, will be used to screen for candidate stimuli of the basolateral receptor sites in developing and mature rats. In parallel, a newly developed in vitro technique will be used to make direct measurements of fluxes of various stimuli across the paracellular regions of single fungiform papillae. Both fluorescent dyes and ion selective microelectrodes will be used to measure fluxes of hydrogen ions due to several acids, various salts of sodium and potassium, calcium ions, and ammonium ion derivatives. Calcium is especially important because it is expected to reduce its own paracellular permeability as well as that of other stimuli. These experiments will determine the actual range of stimulating concentrations of stimuli on the basolateral side of the taste buds, which preliminary results indicate are far lower than the concentrations placed on the tongue. Methods will also be developed to determine the buffering properties of the lateral intercellular spaces for hydrogen and calcium.

描述：（改编自申请人的摘要）。味觉刺激与味蕾中的味觉敏感细胞相互作用，味蕾中的味觉敏感细胞大部分位于舌头上表面的乳头中。通常会摄入具有食欲的物质（例如甜味刺激）；那些厌恶的（例如苦味刺激）会被拒绝，尽管这些倾向可以通过经验来改变。口味偏好发生的一些变化似乎与年龄有关，这在啮齿动物模型中已有充分记录。随着产后早期发育，对氯化钠的味觉敏感性的变化尤其明显。对氯化钠的一些敏感性在出生时就存在，但在以后会变得更加敏感，特别是当动物断奶时。盐味感知有两种模式，它们似乎驻留在味蕾的不同区域。味觉细胞顶端微绒毛上的一个传感器与口腔液体直接接触。另一个被隔离在细胞的基底外侧膜上，因此一些刺激必须通过分隔细胞顶端和基底外侧区域的紧密连接扩散才能到达受体位点。数据表明，钙可以阻断这些基底外侧位点的通路，并且味觉刺激的紧密连接通透性在发育过程中发生变化。味觉神经反应的体内记录，以及电压钳下的感受野，将用于筛选发育中和成熟大鼠的基底外侧受体位点的候选刺激。与此同时，一种新开发的体外技术将用于直接测量跨单个菌状乳头细胞旁区域的各种刺激的通量。荧光染料和离子选择性微电极都将用于测量由几种酸、各种钠盐和钾盐、钙离子和铵离子衍生物产生的氢离子通量。钙尤其重要，因为它有望降低其自身的细胞旁通透性以及其他刺激物的通透性。这些实验将确定味蕾基底外侧刺激物的实际刺激浓度范围，初步结果表明该浓度远低于舌头上的浓度。还将开发确定横向细胞间隙对氢和钙的缓冲特性的方法。