Gustatory coding in brainstem nuclei using a novel c-Fos-tau-LacZ mouse model

项目摘要 肥胖是一个主要的健康问题，大约三分之二的美国人口被认为超重，三分之一的人被归类为肥胖。过度食用高热量食物会显着导致肥胖。因此，识别影响食物选择的因素对于开发有效的肥胖治疗方法非常重要。在这方面，味觉对食物偏好有直接影响。因此，参与大脑如何代表味觉的神经通路有助于我们理解肥胖的病因。最有效和广泛使用的方法来确定的神经基板，味觉的基础是可视化的空间模式的表达的活动依赖性标记，c-Fos的。 最近，开发了Fos-tau-LacZ转基因小鼠系，其中c-Fos基因的激活导致tau连接的β-半乳糖苷酶（β-gal）在激活细胞的细胞质中表达;从而能够检查c-Fos阳性细胞的形态。此外，在这些转基因小鼠中β-gal的持续时间比c-Fos蛋白本身长得多;在脑干中刺激后24小时可以看到β-gal，而c-Fos蛋白持续1-3小时，c-Fos mRNA在刺激后30分钟达到峰值。β-gal和mRNA持续时间之间的这种时间差异使得能够在同一动物内响应于时间上分开的两种刺激（例如β-gal表达和c-Fos mRNA表达）的c-Fos表达可视化。因此，我可以评估单个细胞是否对多种味觉刺激做出反应。 目前的提议将使用Fos-tau-LacZ转基因小鼠来量化脑干味觉核中细胞活化（例如β-gal表达和c-Fos mRNA）的形态和空间差异，以响应不同形式（甜、鲜味/咸味和苦味）和不同味觉享乐（食欲与厌恶）的刺激。此外，该提案还将评估通过删除T1 R3受体（检测这些品质的强制性亚基）而失去甜味和鲜味特异性感觉输入后这种中枢味觉表征的变化。从这个建议获得的数据将提供有价值的洞察力的空间和形态组织内的孤束核的味觉表征。

Project Summary Obesity is a major health issue with approximately two thirds of the U.S. population considered overweight and a third of those classified as obese. Overconsumption of high calorie foods contributes significantly to the development of obesity. Thus, identification of factors that influence food choice is important for the development of effective obesity treatments. In this regard, the sense of taste has a direct impact on food preference. Therefore, the neural pathways involved in how the brain represents taste can contribute to our understanding of the etiology of obesity. One of the most effective and widely-used methods to determine the neural substrate that underlies sensation of taste is visualization of the spatial patterns of expression of the activity-dependent marker, c-Fos. Recently, the Fos-tau-LacZ transgenic mouse line was developed in which activation of the c-Fos gene results in expression of tau-linked Beta-galactosidase (Beta-gal) in the cytoplasm of activated cells; thereby enabling the examination of the morphology of c-Fos positive cells. Furthermore, the perdurance of Beta-gal in these transgenic mice is much longer than c-Fos protein itself; Beta-gal can be seen up to 24 hours post stimulation in the brainstem, whereas c-Fos protein lasts 1-3 hours and c-Fos mRNA peaks 30 min. post stimulation. This difference in timing between Beta-gal and mRNA purdurance enables visualization of c-Fos expression in response to two stimuli, separated temporally, within the same animal (e.g. Beta-gal) expression and c-Fos mRNA expression). Accordingly, I can assess whether individual cells respond to multiple taste stimuli. The current proposal will use Fos-tau-LacZ transgenic mice to quantify morphological and spatial differences in cellular activation (e.g. Beta-gal expression and c-Fos mRNA) in brainstem taste nuclei in response to stimuli of different modalities (sweet, ¿umami¿/savory and bitter) and different taste hedonics (appetitive vs. aversive). Moreover, the proposal will also assess changes in this central taste representation following loss of sweet- and umami- specific sensory input via deletion of the T1R3 receptor- an obligatory subunit for the detection of these qualities. The data obtained from this proposal will provide valuable insight into the spatial and morphological organization of taste representation within the nucleus of the solitary tract.