SALT PREFERENCE--INFLUENCE OF AGE AND STRAIN

该项目的长期目标是确定哪些因素 导致盐(氯化钠)摄入量和喜好的变化。食盐 偏爱指的是钠或氯化钠摄入量超过 生理需要和特别感兴趣的，因为高盐 摄取已经牵涉到发展和维持 人类的原发性高血压。已经确定了两种型号 哪些老鼠表现出明显偏离“物种典型标准” 对盐的偏爱。一种是新生大鼠，自由摄取氯化钠 高达2%和41%的溶液，成年大鼠避免使用。在……里面 相比之下，近交系Fischer-344(F-344)大鼠未能偏爱 甚至是等渗或低渗的氯化钠溶液。这两种型号 在盐偏好的连续体上代表着相反的极端。 电生理、手术和行为方法将是 用于定义作为这些机制基础的味觉机制 行为。 这一提议的一个重点是假设压力和年龄 味蕾对阿米洛利敏感钠转运的差异 导致人们对盐的偏好有很大差异。电生理学 鼓索神经多单位活动的反应记录 对氯化钠的刺激，在阿米洛利预处理前后都会用到 评估阿米洛利敏感的钠转运机制。这 方法将与遗传方法，即共同隔离分析相结合，以 评估增强的味蕾对阿米洛利的敏感性在 F-344大鼠对氯化钠的厌恶。切断鼓索神经， 它已经被发现可以极大地消除对氯化钠的厌恶 F-344大鼠，将被用来评估外周神经的贡献 味觉信号指向食盐的偏好和摄入量。行为研究 将包括对新生大鼠进行口腔内输液；舔舔的措施 在简单访问测试和传统访问测试中对氯化钠溶液的行为 两瓶偏好测试法。

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.