SALT PREFERENCE--INFLUENCE OF AGE AND STRAIN

本项目的长期目标是确定 导致盐（NaCl）摄入量和偏好的变化。 盐 偏好是指摄入钠或NaCl超过 由于高盐， 摄入量与发展和维持有关 人类原发性高血压 两个模型已经确定， 这些大鼠显示出与“物种典型标准”的显著偏离， 盐的偏好。 一种是新生大鼠，自由摄取NaCl 高达2%和41%的溶液，成年大鼠避免使用。 在 相比之下，近交系Fischer-344（F-344）大鼠未能偏好 甚至等渗或低渗NaCl溶液与水混合。 这两款车型 代表了盐偏好连续体的两个极端。 电生理学，外科手术和行为方法将是 用于定义这些基础的味觉机制， 行为。 这一建议的一个焦点是假设应变和年龄 味蕾对阿米洛利敏感的钠转运的差异 导致人们对盐的偏好差异很大。 电生理 鼓索神经多单位活动的记录 在阿米洛利预处理之前和之后， 评估阿米洛利敏感的钠转运机制。 这 方法将结合遗传方法，共分离分析， 评价增强的阿米洛利敏感性的味蕾在 F-344大鼠的NaCl厌恶。 切断鼓索神经， 已经发现其显著地消除了 F-344大鼠，将被用来评估外周血淋巴细胞的贡献。 味觉信号对NaCl偏好和摄入的影响。 行为研究 将包括新生大鼠的口内输注;舔的措施 在简单的访问测试以及传统的NaCl溶液中的行为 两瓶偏好测试方法。

The long range goal of this project is to identify factors which contribute to variations in salt (NaCl) intake and preference. Salt preference refers to the ingestion of sodium or NaCl in excess of physiological need and is of particular interest because high salt intake has been implicated in the development and maintenance of essential hypertension in humans. Two models have been identified in which rats show significant departures from the "species typical norm" of salt preference. One, the neonatal rat, freely ingests NaCl solutions as high as 2% and 41% which are avoided by adult rats. In contrast, an inbred strain, the Fischer-344 (F-344) rat, fails to prefer even isotonic or hypotonic NaCl solutions to water. These two models represent opposite extremes on a continuum of salt preference. Electrophysiological, surgical and behavioral approaches will be utilized to define the gustatory mechanisms which underlie these behaviors. A focus of this proposal is the hypothesis that strain and age differences in amiloride-sensitive sodium transport at the taste bud contribute to wide variations in salt preference. Electrophysiological recordings of multiunit activity of the chorda tympani nerve in response to NaCl stimuli, before and after amiloride pretreatment, will be used to assess amiloride-sensitive sodium transport mechanisms. This approach will be combined with a genetic one, cosegregation analysis, to evaluate the role of enhanced amiloride-sensitvity of taste buds in the NaCl aversion of F-344 rats. Transection of the chorda tympani nerve, which has been found to dramatically eliminate the NaCl aversion of F-344 rats, will be employed to assess the contribution of peripheml gustatory signals to NaCl preference and intake. Behavioral studies will include intraoral infusions in neonatal rats; measures of licking behavior to NaCl solutions in brief access tests as well as traditional two-bottle preference testing methods.