PHYSICOCHEMICAL INVESTIGATION OF TASTE

描述(改编自调查人员摘要)：规则 在一个狭窄的范围内的内部液体的酸度(PH)对所有 动物。味觉系统起着防止过量摄入的作用。 指食物和饮料中的酸，其中的酸度过高会引起强烈的酸 而不是与生俱来的厌恶。味觉感受器的作用机制 细胞对酸的反应(酸味转导)将用味觉来研究 从啮齿动物身上分离出的花蕾和味觉细胞。初步实验 表明细胞外pH的变化(酸刺激)反映在 细胞内pH的比例变化，表明pH传感是一种 细胞内过程。此外，细胞内钙水平的变化 改变体内的pH值，表明钙可能参与了 酸敏转导途径。这一假说将用pH值来检验。 和钙敏感荧光染料跟随酸诱导的变化 细胞内的pH值和随后可能的细胞内钙的变化。 将评估在酸刺激过程中膜电导的变化 使用膜片钳记录分离的味觉细胞来帮助建立 预测的质子传输路径的性质。免费实验 将涉及一种允许从鼓索味道进行录音的准备 神经纤维同时电压钳制感受器上皮。这个强大的 这项技术将有助于确定酸感应部分是否 细胞顶端或基侧。对铵盐的味觉反应 共享酸感测系统的许多特性，并将对其进行检查 在使用类似技术的一系列单独的实验中。结果是 这些研究将为酸(酸)口味的接受提供新的见解， 它在pH平衡中起着重要作用。

DESCRIPTION (Adapted from the Investigator's Abstract): Regulation of the acidity (pH) of internal fluids within a narrow range is essential for all animals. The taste system plays a role in guarding against excessive intake of acid in foods and beverages with hyperacidity evoking an intense sour taste than is innately aversive. The mechanisms by which taste receptor cells respond to acid (sour taste transduction) will be studied using taste buds and taste cells isolated from rodents. Preliminary experiments indicate that changes in extracellular pH (acid stimulation) are mirrored by proportionate changes in intracellular pH, suggesting that pH-sensing is an intracellular process. In addition, changes in intracellular calcium levels alter internal pH, indicating that calcium may be involved in the acid-sensing transduction pathway. This hypothesis will be tested using pH- and calcium-sensitive fluorescent dyes to follow acid induced changes in intracellular pH and possible subsequent changes in intracellular calcium. Changes in membrane conductance during acid stimulation will be assessed using patch-clamp recording from isolated taste cells to help establish the nature of the predicted proton transport pathway. Complimentary experiments will involve a preparation which permits recording from chorda tympani taste nerve fibers while voltage-clamping the receptor epithelium. This powerful technique will be useful in determining whether the acid-sensing portions of the cells are apical or basolateral. Taste responses to ammonium salts share many of the properties of the acid sensing system and will be examined in a separate series of experiments using similar techniques. The results of these studies will provide new insights into sour (acid) taste reception, which plays an important role in pH balance.