Transport Mechanisms in Mammalian Taste Transduction

味觉是一个复杂的过程，从舌头开始，舌头的表层细胞上皮包含味蕾。许多味觉化合物可能与味觉细胞膜上的特定受体分子结合。但是盐形成了一种完整的味觉剂，在溶液中产生离子，现在被认为是通过细胞膜的运输过程直接刺激味蕾细胞。这些离子可能利用膜上的特定通道，其方式类似于利用离子通道刺激神经和肌肉的可兴奋膜。理解味觉转导是化学感觉系统研究的一个主要目标。味觉转导是指一种特定的刺激能特异性地刺激一个感觉细胞。本项目将通过将舌上皮组织的生理学实验与味觉受体的神经生理学实验相结合来研究味觉转导。我们将在体外测试舌头组织，以精确测量离子流动，并通过与实验数据的比较，完善和扩展离子在上皮上运输过程的数学模型。这些数据将与神经生理学实验中已知的味觉神经兴奋数据进行比较。实验和模型应该解决味觉转导的哪些方面可以通过舌上皮的特性来解释。该模型包含了所有组成膜的组织，以及味蕾所在的上皮的拓扑结构；该模型可以扩展到包括不同的细胞类型和不同的离子。这项研究涉及一种新的味觉机制定量方法，将数学、化学和生物学强有力地结合在一起；它可以用于食品工业的味觉相互作用分析，并将在化学感觉科学和神经生理学方面产生重大影响。

Taste is a complex process beginning in the tongue, where the surface layer of cells, the epithelium, contains taste buds. Many taste compounds probably bind to specific receptor molecules on membrane of the taste sensory cells. But salts form a whole class of tastants that produce ions in solution, and now are thought to stimulate the cells of the taste buds directly, by transport processes across the cell membrane. These ions may use specific channels in the membrane in a way similar to the use of ionic channels in to stimulate excitable membranes of nerve and muscle. Understanding taste transduction, by which a particular stimulus specifically excites a sensory cell, is a major goal of chemosensory systems research. This project will approach taste transduction by linking experiments on the physiology of tongue epithelial tissue with neurophysiology of taste receptors. In vitro tongue tissue will be tested to precisely measure ionic flows, and a mathematical model of ionic transport processes across the epithelium will be refined and expanded by comparisons to data from experiments. These data will be compared to known data on excitation of taste nerves from neurophysiology experiments. Experiments and modelling should resolve which aspects of taste transduction can be explained by properties of the tongue epithelium. The model incorporates organization of all the component membranes, and the topology of the epithelium in which the taste buds are imbedded; the model can be extended to include different cell types and different ions. This study involves a novel quantitative approach to taste mechanisms, with a powerful merging of mathematics, chemistry, and biology; it may be useful in analyses of tastant interactions by the food industry, and will have high impact in chemosensory science and neurophysiology as well.