VOLTAGE-DEPENDENT ION CHANNELS IN GUSTATION

描述（由申请人提供）：味觉感知是由味蕾细胞表面上的sapid分子与蛋白质的相互作用引发的。这些味觉信号随后被转换，在味蕾中处理，编码并通过颅神经传输到大脑。我们研究计划的长期目标是从分子水平上鉴定和功能表征参与味蕾味觉信号转导和编码以及中枢神经系统解码的关键蛋白质，并最终重建味觉和感知的分子事件。我们已经使用分子克隆和功能分析，以确定和表征一些味觉转导组件，包括G蛋白偶联味觉受体T1 R3，G蛋白亚基和瞬时受体电位离子通道TRPM 5。为了了解TRPM 5下游的分子事件，并揭示负责酸味和咸味的离子通道，我们已经确定了味蕾细胞中六个电压依赖性钙通道的表达。本发明的具体目的是：1）鉴定和共定位味蕾细胞中具有已知味觉信号分子的电压依赖性钙通道亚基; 2）异源表达和功能表征从味蕾分离的这些电压依赖性钙通道的新同种型; 3）确定这些电压的可能作用-通过监测这些通道的药理学和遗传学扰动对细胞内钙升高的影响，浓度和突触活动的味蕾细胞中响应于味觉刺激; 4）最后，通过味觉神经记录和突变动物的动物行为测试来确定这些电压依赖性钙通道在味觉感觉中的可能作用。这些研究的结果将产生新的见解的酸，盐，苦，甜和鲜味的味道转导，突触传递和外周编码的分子机制在味觉的最终器官。从这一奋进中获得的知识将进一步加深我们对味觉障碍如味觉缺失、味觉障碍、味觉减退和味觉丧失的分子基础的理解，并可能导致有效的治疗。

DESCRIPTION (provided by applicant): Taste perception is initiated by the interaction of sapid molecules with proteins on the surface of taste bud cells. These gustatory signals are subsequently transduced, processed in taste buds, coded and transmitted by cranial nerves to the brain. The long-term objective of our research program is to molecularly identify and functionally characterize key proteins that are involved in taste signal transduction and coding in taste buds, and decoding in the central nervous system, and eventually to reconstruct the molecular events of taste sensation and perception. We have used molecular cloning and functional analyses to identify and characterize a number of taste transduction components, including a G-protein coupled taste receptor T1R3, G protein subunits and a transient receptor potential ion channel TRPM5. In order to understand the molecular events downstream of TRPM5 and to reveal ion channels that are responsible for sour and salty tastes, we have determined the expression of six voltage-dependent calcium channels in taste bud cells. The specific aims of this proposal are: 1) to identify and colocalize voltage-dependent calcium channel subunits with known taste signaling molecules in taste bud cells; 2) to heterologously express and functionally characterize novel isoforms of these voltage-dependent calcium channels isolated from taste buds; 3) to determine possible roles of these voltage-dependent calcium channels in taste bud synaptic transmission by monitoring the effect of pharmacological and genetic perturbation of these channels on the elevation of intracellular calcium concentrations and synaptic activity in taste bud cells in response to taste stimuli; 4) finally, to determine possible roles of these voltage-dependent calcium channels in taste sensation by gustatory nerve recording and animal behavioral tests with mutant animals. The results of these studies will yield new insights into the molecular mechanisms underling sour, salt, bitter, sweet and umami taste transduction, synaptic transmission and peripheral coding in the end organs of taste. The knowledge gained from this endeavor will further our understanding of the molecular bases of taste disorders such as malgeusia, dysgeusia, hypogeusia and ageusia and may lead to effective treatment.