TASTE PREFERENCE: INFLUENCE OF AGE AND EARLY EXPERIENCE

这些研究的目的是确定发展的原因， 大鼠味觉偏好的变化。 使用盐（NaCl）偏好作为 模型系统，在早期发展的两个因素将被检查， 影响摄入量和偏好。 首先是味觉的年龄变化 敏感性，这可能有助于口味偏好的变化。 的 第二是断奶前的味觉暴露，这可能会影响成年人的味觉 敏感性和/或偏好。 建议的研究是基于我们的研究， 这项研究表明，未成熟的大鼠对 与成人相比，高渗盐溶液，一个因素可能是 导致这种高盐摄入量的原因是 断奶仔猪的味觉系统对高渗盐浓度的反应。 的 拟议的研究涉及开发行为范式， 断奶和成年动物对促味剂的阈和阈上敏感性 不依赖于偏好或享乐措施的大鼠。 这些研究 然后将扩展到早期品味的贡献的检查 体验品味的发展。 本项目的长期目标 是了解盐偏好升高的原因， 人类的摄入量与发展和维持 原发性高血压 在检查盐敏感性和偏好的规范发展时 我们将利用两种技术来评估味觉敏感性-（i） 操作性味觉辨别任务;以及（ii）采取以下步骤的程序： 本发明的高浓度特异性的优点在于， 味觉厌恶条件反射中的“前暴露效应”。 我们还将比较 对酸和甜的盐敏感性的发展。 味道 新生期味觉剥夺或选择性味觉暴露大鼠的功能 然后将检查暴露情况，以确定早期经验是否 影响味觉的发展 味觉减退 刺激将通过人工饲养程序来完成， 使用慢性胃内插管，并允许大鼠幼崽在 产后第4天至第18天完全没有哺乳。

The objective of these studies is to to identify causes of developmental changes in taste preference in the rat. Using salt (NaCl) preferences as a model system, two factors in early development will be examined which may affect intake and preference. The first is age-related changes in taste sensitivity which may contribute to changes in taste preference. The second is preweaning taste exposure which may influence adult taste sensitivity and/or preference. The proposed studies are based on our reent work indicating that immature rats express elevated preference for hypertonic saline solutions compared to adults, and that one factor likely to contribute to this elevated saline intake is a relative insensitivity of the weanling's taste system to hypertonic saline concentrations. The proposed studies involve developing behavioral paradigms for evaluating threshold and suprathreshold sensitivity to tastants in weanling and adult rats without reliance on preference or hedonic measures. These studies will then be extended to an examination of the contribution of early taste experiences to taste development. The long term objective of this project is to understand the causes of elevated salt preference because high salt intake in humans has been implicated in the development and maintenance of essential hypertension. In examining the normative development of salt sensitivity and preference we will utilize two techniques for assessing taste sensitivity----(i) an operant taste discrimination task; and (ii) a procedure which takes advantage of the high degree of concentration specificity of the "preexposure effect" in taste aversion conditioning. We will also compare the development of salt sensitivity to that of sour and sweet. Taste function of rats exposed to neonatal taste deprivation or selective taste exposure will then be examined to determine whether early experience influences the course of taste development. Reductions in taste stimulation will be accomplished by an artificial rearing procedure which uses chronic intragastric cannulas and allows rat pups to be reared in the total absence of nursing from Postnatal Days 4 through 18.