SALT TASTE TRANSDUCTION AND ITS HORMONAL REGULATION

拟议工作的最终目标是确定机制 参与菌状和环状结构中盐类的转运 味觉感受器细胞与盐转导元件的调节 多肽激素精氨酸加压素和心钠素。 使用电生理学方法，我们将解决以下问题 具体目标： 1.盐味刺激的转导机制是什么？ 仓鼠的菌状和环状味觉感受器细胞？钠盐 真菌样味觉感受器细胞的转导是通过Na内流实现的 对阿米洛利敏感的钠通道，但也有阿米洛利- 不能很好地理解的不敏感组件。圆润口感 受体细胞对钠盐也有反应，但它们的转导机制 还没有确定。使用膜片钳记录和 对味觉组织上皮运输的测量，我们将确定 菌状和环状味觉感受器的基本电生理学 细胞。我们还将确定离子钠在这些生物体内的运输途径 细胞，以阐明盐转导的机制。 2.血管加压素和心钠素对血管紧张素转换酶活性的影响 盐类的传感元件？我们最近的工作表明 加压素增强真菌样味觉中对阿米洛利敏感的钠电流 与受体细胞结合的初步证据表明 心钠素减少跨上皮钠流量，提示 外周钠盐转导可能受激素调节。我们会 描述加压素和心房肌的急性和慢性影响 利钠肽对跨上皮钠转运和钠转导的影响 全小区和单通道级别的通道，特别是 注意阿米洛利敏感的钠通道。然后我们将确定 参与这些细胞反应的靶点和途径 两种荷尔蒙。 总体而言，这些研究将阐明基本的电生理 味觉感受器细胞的特性及钠盐转导机制 在仓鼠里。此外，它将首次查看 激素在外周味觉调控中的作用 响应性。这些研究将加强对营养素的理解 化学接受及其调控，并提供对 神经元是如何传递感觉刺激的。

The ultimate goal of the proposed work is to determine the mechanisms involved in the transduction of salts in the fungiform and circumvallate taste receptors cells and the regulation of salt transducing elements by the peptide hormones arginine vasopressin and atrial natriuretic peptide. Using an electrophysiological approach, we will address the following specific aims: 1. What are the mechanisms for transduction of salty taste stimuli in the fungiform and circumvallate taste receptor cells of hamsters? Sodium salt transduction in fungiform taste receptor cells occurs by Na influx through amiloride-sensitive Na channels, but there is also an amiloride- insensitive component that is not well understood. Circumvallate taste receptor cells also respond to Na salts, but their transduction mechanisms have not been determined. Using a combination of patch clamp recording and epithelial transport measurements on taste tissue, we will determine the basic electrophysiology of fungiform and circumvallate taste receptor cells. We will also determine the ionic Na transport pathways in these cells in order to elucidate the mechanisms for salt transduction. 2. What are the effects of vasopressin and atrial natriuretic peptide upon the transducing elements for salts? Our recent work showing that vasopressin enhances amiloride-sensitive Na currents in fungiform taste receptor cells coupled with preliminary evidence which demonstrates that atrial natriuretic peptide reduces transepithelial Na flux, suggests that peripheral Na salt transduction may be hormonally regulated. We will characterize the acute and chronic effects of vasopressin and atrial natriuretic peptide upon transepithelial Na transport and Na transducing channels at the whole cell and single channel level, paying particular attention to the amiloride-sensitive Na channel. We will then determine the targets and the pathways involved in the cellular response to these two hormones. Overall, these studies will elucidate basic electrophysiological properties of taste receptor cells and mechanisms for Na salt transduction in the hamster. Additionally, it will, for the first time, look at the role of hormones in the regulation and modulation of peripheral gustatory responsiveness. These studies will enhance understanding of nutrient chemoreception and its regulation as well as provide general insights into how neurons transduce sensory stimuli.