Akabas M, Dodd J, al-Awqati Q
Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
J Membr Biol. 1990 Mar;114(1):71-8. doi: 10.1007/BF01869386.
The gustatory sensory system provides animals with a rapid chemical analysis of a potential food substance providing information necessary to facilitate ingestion or rejection of the food. The process of gustatory transduction is initiated in the taste cells in the lingual epithelium. However, due to the small size, scarcity of the cells and their location, embedded in a keratinized squamous epithelium, it has been difficult to study the primary events in the transduction process. Recently, we have developed a preparation of dissociated rat taste cells that permits studies of the taste transduction process in single isolated cells. We have now investigated the electrophysiological properties of the rat taste cells using the patch-clamp technique. We have identified two populations of cells within the taste bud: one expressing a voltage-dependent potassium current and the second containing both voltage-dependent sodium and potassium currents. The potassium current in both cell groups is blocked by external TEA, Ba2+, and quinine. Two types of K+ channels have been identified: a 90-pS delayed rectifier K+ channel and a "maxi" calcium-activated K+ channel. The sodium current is blocked by TTX, but not by amiloride.
味觉感觉系统为动物提供对潜在食物物质的快速化学分析，提供促进食物摄取或拒绝所必需的信息。味觉转导过程始于舌上皮中的味觉细胞。然而，由于这些细胞体积小、数量稀少且位于角化鳞状上皮中，研究转导过程中的主要事件一直很困难。最近，我们开发了一种解离大鼠味觉细胞的制备方法，可用于研究单个分离细胞中的味觉转导过程。我们现在使用膜片钳技术研究了大鼠味觉细胞的电生理特性。我们在味蕾中鉴定出两种细胞群：一种表达电压依赖性钾电流，另一种同时含有电压依赖性钠电流和钾电流。两个细胞群中的钾电流均被细胞外的四乙铵（TEA）、钡离子（Ba2+）和奎宁阻断。已鉴定出两种类型的钾通道：一种90皮秒延迟整流钾通道和一种“大电导”钙激活钾通道。钠电流被河豚毒素（TTX）阻断，但不被氨氯吡脒阻断。
