HIGH THROUGHPUT SCEENS FOR ASSESSING TASTE SENSITIVITY

人类患有各种各样的味觉障碍，损害了他们获取必要营养、调节消化酶分泌以及享受生活中一种简单的快乐--吃的能力。由于这些疾病几乎没有有效的治疗方法，即将进行的对小鼠基因组的全面分析为帮助填补这一空白提供了巨大的希望。由于缺乏高通量的筛选方案，味觉遗传学家识别小鼠味觉敏感度的遗传变化的能力受到了阻碍。因此，大多数味觉遗传学家被迫使用一种称为两瓶偏好测试的极低吞吐量和解释有限的程序。在过去的十年里，味觉心理物理学家开发了一种高通量的程序来评估大鼠的味觉敏感性，称为简单访问味觉测试。在这个程序中，动物在简短(例如，10秒)的试验期间可以获得单一的味觉刺激，并用自动Gustometer测量舔食反应。使用这种设备，人们可以在30分钟的测试过程中以随机顺序呈现几种味觉刺激(例如，不同浓度的蔗糖)，导出稳健的浓度-响应函数，并相对确信舔食反应处于味觉控制之下，并且不会被味觉刺激的摄食后效应所混淆。我们已经成功地将这一方法应用于大鼠的味觉功能研究，并在此建议将这一可靠、易于使用和高通量的程序应用于小鼠。为此，将开发二次筛查，用于检测野生型和突变C57BL/6小鼠。由于这一筛选将使用每种味觉刺激(奎宁、氯化钠和蔗糖)的大量浓度进行，因此它将能够检测到味觉敏感度在两个方向上的粗略和细微变化。在通过二次筛选获得的知识的基础上，将为一次筛选选择临界浓度，以提供相对快速的味觉敏感性评估。利用主屏幕识别的离群值可以经受次屏幕以进行确认。将为这两个屏幕建立一个标准数据库，并向科学界提供。开发的化验程序将适用于经验有限的单一实验室技术人员。

Humans suffer from a variety of taste disorders that impair their ability to acquire essential nutrients, regulate secretion of digestive enzymes, and enjoy one of life's simple pleasures-- eating. As there are few effective therapies for these disorders, the impending comprehensive analysis of the mouse genome offers great promise for helping fill this void. The ability of taste geneticists to identify genetically-based alterations in murine taste sensitivity has been impeded by the absence of a high-throughput screening protocol. As a result, most taste geneticists are forced to use an extremely low- throughput and interpretively limited procedure called 2-bottle preference testing. Over the last decade, taste psychophysicists have developed a high-throughput procedure for assessing taste sensitivity in rats, called brief-access taste testing. In this procedure, animals are provided with access to a single taste stimulus during brief (e.g., 10 sec) trials, and licking responses are measured with an automated gustometer. Using this device, one can present several taste stimuli (e.g., different concentrations of sucrose) during a 30-min test session in a randomized order, derive a robust concentration-response function, and be relatively confident that the licking responses are under orosensory control and not confounded by postingestive effects of the taste stimulus. We have successfully applied this methodology to study taste function in rats, and we propose here to adapt this reliable, easy-to-use, and high-throughput procedure to mice. To this end, a secondary screen will be developed for testing wild-type and mutant C57BL/6 mice. Because this screen will be conducted with an expansive array of concentrations of each taste stimulus (quinine, NaCl, and sucrose), it will be able to detect gross and subtle alterations in taste sensitivity in either direction. One the basis of the knowledge gained through the development of the secondary screen, critical concentrations will be chosen for a primary screen to provide a relatively quick assessment of taste sensitivity. Outliers identified with the primary screen can be subjected to the secondary screen for confirmation. A normative data-base for both screens will be established and made available to the scientific community. The assay procedures developed will be applicable by a single laboratory technician with limited experience.