Neurotransmission in tastebuds

味蕾的神经传递

• 批准号: 9397936
• 负责人: Sue C. Kinnamon
• 金额: $ 44.38万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9397936
• 关键词: Acids; Action Potentials; Address; Affect; Altered Taste; Behavior; Behavioral Paradigm; Brain Stem; Calcium; Cell Nucleus; Cells; Chemicals; Citric Acid; Data; Detection; Development; Dose; Eating; Enterobacteria phage P1 Cre recombinase; Event; Fiber; Gene Targeting; Glossopharyngeal nerve structure; Image; Knock-out; Lead; Light; LoxP-flanked allele; Molecular; Morphology; Mus; NTPDase2; Nerve; Nerve Fibers; Nervous system structure; Neurons; Neurotransmitters; Norepinephrine; Nucleus solitarius; Nutritional; Obesity; Oral; Oral cavity; P2X-receptor; Pattern; Pharmacologic Substance; Pharmacology; Physiological; Play; Poison; Purinoceptor; Receptor Cell; Role; Salts; Serotonin; Serotonin Receptors 5-HT-3; Signal Transduction; Sodium Chloride; Stimulus; Structure of geniculate ganglion; Supporting Cell; Synapses; System; Taste Buds; Taste Perception; Taste aversion; Testing; Tongue; Type II Epithelial Receptor Cell; Type III Epithelial Receptor Cell; Vesicle; afferent nerve; awake; cell type; chorda tympani; ectoATPase; gamma-Aminobutyric Acid; ganglion cell; immunoreactivity; in vivo; mouse model; neurotransmission; neurotransmitter release; optogenetics; patch clamp; presynaptic; receptor; relating to nervous system; response; taste stimuli; taste system; transmission process; uptake

PROJECT SUMMARY Type III “presynaptic” taste cells respond to sour and some salty stimuli with action potentials and release neurotransmitter at conventional synapses with afferent nerve fibers. The identity of the transmitters involved, however, is still unclear. We have shown previously that all taste stimuli (including sour and salty) require ATP signaling to neural P2X receptors for transmission to afferent fibers. Nonetheless, ATP release from Type III cells has not been detected. Conversely, Type III cells do release serotonin (5-HT) which activates 5-HT3 receptors on afferent nerve fibers but neither knockout nor pharmacological inhibition of 5-HT3 completely eliminates responses to acids or salts, suggesting other neurotransmitters are involved. One problem in studying transmission from Type III cells is that the conventional stimuli used to activate these cells -- acids, salts, and KCl -- all have non-specific effects on other cell types in the taste bud. To circumvent this problem, we employ an optogenetic strategy permitting direct stimulation of Type III cells with light rather than chemicals. We developed a mouse that expresses Cre recombinase selectively in type III taste cells relying on Pkd2l1 as a Cre driver. When these Pkd2l1-Cre mice are crossed with “floxed” channelrhodopsin (ChR2) mice ChR2 is faithfully expressed in taste cells immunoreactive for PKD2L1 with no off-target expression in other taste cell types. Flashing 470 nm light onto the tongue elicits responses in the chorda tympani and glossopharyngeal nerves that are robust and repeatable, resembling responses to sour and salty stimuli. In this proposal we will utilize these Pkd2l1-ChR2 mice plus other gene-targeted mice to investigate the neurotransmitters that are used by these cells to communicate with the nervous system, and the perceptual qualities evoked by selective stimulation of PKD2l1 Type III cells. Aim 1 will investigate the role of ATP and other neurotransmitters (i.e., 5-HT, GABA, and NE) in activating geniculate ganglion neurons that selectively innervate Type III cells. Calcium imaging of isolated geniculate ganglion cells will identify transmitters that activate these neurons, and chorda tympani and glossopharyngeal nerve responses to light in the Pkd2l1- ChR2 mice will allow us to test the role of their cognate receptors in vivo. Aim 2 will address the perceptual quality elicited by stimulation of Pkd2l1-ChR2 cells, using behavioral paradigms, and cFos activation will be used to address the central representation of PKD2L1-expressing Type III cells. In Aim 3 we will test the hypothesis that PKD2L1-Type III cells participate in an intragemmal (intra taste bud) circuit, resulting in modulation of other taste qualities, particularly those transduced by Type II cells. Results from these studies will provide important new information about transduction, afferent neurotransmission, and intragemmal signaling in Type III taste cells.

项目摘要 III型“突触前”味道细胞对酸和一些具有动作电位的咸刺激反应并释放 传统突触的神经递质具有传入神经纤维。涉及的发射机的身份， 但是，仍然不清楚。我们之前已经证明，所有味道刺激（包括酸和咸）都需要ATP 向神经P2X受体发出信号，以传播传入纤维。尽管如此，ATP从III型释放 细胞尚未检测到。相反，III型细胞确实释放了激活5-HT3的5-羟色胺（5-HT） 传入神经纤维的受体，但既不完全敲除也不完全抑制5-HT3 消除对酸或盐的反应，表明涉及其他神经递质。一个问题 研究从III型细胞传播的是，用于激活这些细胞的常规刺激 - 酸， 盐和KCL - 所有这些都对味蕾中的其他细胞类型都有非特异性作用。要解决这个问题， 我们采用光遗传策略，允许直接刺激III型细胞，而不是 化学物质。我们开发了一种在III型味道细胞中选择性地表达CRE重组酶的小鼠 PKD2L1作为CRE驱动程序。当这些PKD2L1-CRE小鼠与“ Floxed”通道Ropopsin（CHR2）小鼠交叉时 CHR2在PKD2L1的免疫反应性中忠实地表达，而在其他方面没有脱靶表达 味道细胞类型。闪烁470 nm的光在舌头上引起舌头的反应 全咽神经坚固且可重复，类似于对酸和咸刺激的反应。 该建议我们将利用这些PKD2L1-CHR2小鼠以及其他靶向基因的小鼠进行研究 这些细胞用来与神经系统通信的神经递质和感知 选择性刺激PKD2L1 III型细胞引起的质量。 AIM 1将调查ATP和 其他神经递质（即5-HT，GABA和NE）在激活Genatigation神经元中，有选择地 支配III型细胞。孤立的遗传神经节细胞的钙成像将确定发射机 激活这些神经元，chorda tympani和脑咽咽神经对pKD2L1-的神经反应 CHR2小鼠将使我们能够在体内测试其同源受体的作用。 AIM 2将解决感知 使用行为范式刺激PKD2L1-CHR2细胞引起的质量，CFOS激活将为 用于解决表达PKD2L1型III细胞的中心表示。在AIM 3中，我们将测试 假设PKD2L1型III细胞参与了符号内（味蕾内）电路，从而导致 调节其他口味质量，尤其是由II型细胞翻译的味道。这些研究的结果 将提供有关翻译，传入神经传递和内膜内的重要新信息 III型味道细胞中的信号传导。