"Mechanisms underlying nicotine induced neuronal toxicity in zebrafish"

描述(申请人提供)：胚胎暴露于尼古丁会在不同程度上对人类发育产生有害后果。这种暴露会导致与学习和记忆相关的认知能力和行为的长期变化。许多哺乳动物模型已经被用来理解尼古丁是如何发挥这种作用的，但这是困难的，因为大多数哺乳动物的行为及其背后的神经系统是复杂的。我们正在研究尼古丁暴露对模式脊椎动物斑马鱼的影响，目的是将尼古丁暴露造成的行为异常与脊髓神经元和相关脊髓肌肉系统的发育变化联系起来。斑马鱼胚胎对尼古丁暴露敏感(Svoboda et.Al，2002)。暴露在尼古丁中的胚胎在通常不游泳的时候会表现出游泳的行为。另一方面，将胚胎长期暴露在尼古丁中会导致瘫痪。这两种行为表型向我们指出了斑马鱼中可能因胚胎尼古丁暴露而改变的候选细胞类型。在这项提案中，将确定胚胎尼古丁暴露于脊髓神经元和相关肌肉系统的后果。据我们所知，这是首次尝试利用斑马鱼模型来了解胚胎尼古丁暴露的后果。其目的是：1)系统地鉴定和表征所有斑马鱼的nAChRs，2)在机制水平上确定尼古丁暴露对运动神经元和肌肉发育的影响，3)在机制水平上确定尼古丁暴露对胚胎感觉神经元发育的影响，4)确定由于短暂的胚胎尼古丁暴露而产生的表型是否持续到成年。这些目标中的每一个都涉及一个基本问题，即外源尼古丁如何在脊椎动物发育过程中潜在地发挥其作用。首先，他们描述了早期胚胎接触尼古丁导致的行为和神经解剖学表型。其次，它们提供了对这些表型如何产生的机械性洞察。这项工作是发育神经毒理学的基础研究。它的作用是建立一个基础，使斑马鱼可以在体内被用来解开发育过程中尼古丁暴露影响的机制。

DESCRIPTION (provided by applicant): Embryonic exposure to nicotine has deleterious consequences on human development at various levels. Such exposure can lead to long term changes in the cognitive abilities and behaviors related to learning and memory. Many mammalian models have been employed to understand how nicotine can exert such effects, but this is difficult because most mammalian behaviors and the nervous system underlying them are complex. We are studying the effects of nicotine exposure in a model vertebrate, the zebrafish, with the goal of linking behavioral abnormalities created by nicotine exposure to developmental alterations in spinal neurons and associated spinal musculature. Zebrafish embryos are sensitive to nicotine exposure (Svoboda et. al, 2002). Embryos acutely exposed to nicotine exhibit a swimming-like behavior at time when they typically do not swim. On the other hand, chronically exposing embryos to nicotine, results in paralysis. These two behavioral phenotypes point us toward candidate cell types that may be altered in zebrafish by embryonic nicotine exposure. In this proposal the consequences of embryonic nicotine exposure on spinal neurons and associated musculature will be determined. To our knowledge, this is the first attempt at utilizing the zebrafish model to understand the consequences of embryonic nicotine exposure. The aims are: 1) To systematically identify and characterize all of the zebrafish nAChRs, 2) to determine the consequences of nicotine exposure on motoneuron and muscle development at the mechanistic level, 3) to determine the consequences of nicotine exposure on embryonic sensory neuron development at the mechanistic level, 4) To determine if phenotypes that arise form transient embryonic nicotine exposure persist into adulthood. Each of these aims addresses a fundamental issue relating to how exogenous nicotine potentially exerts its effects during vertebrate development. First, they describe behavioral and neuroanatomical phenotypes that result from early embryonic exposure to nicotine. Secondly, they provide mechanistic insight into how those phenotypes could arise. The work is basic research in developmental neurotoxicology. It serves to establish a foundation whereby zebrafish can be utilized in vivo to unravel the mechanisms that underlie the effects of nicotine exposure during development.