TRANSMITTER RELEASE IN A MODEL OF HYPERACTIVITY

申请人最近确认了突变的小鼠科博拉是一种 一种新的运动量超过的多动动物模型 对照组小鼠3倍。她已经证明了多动症 由Cooboma小鼠表达的是Snap缺失的结果 吉恩。该基因编码SNAP-25，是一种神经元特异性蛋白，在 在递质中起主要作用的突触前神经末梢 放手。Snap-25是机械的一个组件，对于 在突触前膜上对接和握持突触小泡 准备迎接钙离子引发的递质胞吐作用。因此，尽管如此， 发射器释放中的缺陷可能是由于SNAP- 25的表达导致多动症的表达。事实上，在那里 似乎是多动症的多巴胺能成分，就像 申请人还发现了严重的行为异常作为回应 多巴胺仿生学。据推测，水泡的异常 功能导致胞浆多巴胺浓度升高 最终导致不受调控的非胞吐多巴胺释放 表现为多动症。这项建议侧重于钙离子介导的 短暂性脑缺血再灌注损伤小鼠的递质释放和多巴胺功能 隔离引起多动的突触事件。具体的 目的是：1)定义囊泡神经递质的异常 放手。个人释放事件将被记录并由药物诱导 评估版本中的更改。2)评估以下方面的贡献 儿茶酚胺能神经传递对运动生成的影响 假瘤小鼠的多动症。这一贡献将受到考验 通过转基因救援实验取代SNAP-25 儿茶酚胺能细胞。3)鉴定体内神经化学缺陷 假瘤小鼠潜在的多动症。这些实验将 将体外鉴定的细胞缺陷与功能性 活体分析。4)确定涉及到的细胞机制 使用经典行为药理学的多动症。吸毒 已知影响突触前多巴胺终末，包括存储， 合成和释放，我们将建立多巴胺之间的直接联系 通过这一活体实验检测终末期功能障碍和多动症。这个 小鼠突变缺陷症代表了一种前所未有的模型 研究单个已知基因对复合体的贡献 人类的多因素表型，包括以下疾病 注意缺陷多动障碍和多发性抽动症。

The applicant has recently identified the mouse mutant coloboma as a novel animal model of hyperactivity with locomotor activity exceeding 3 times control mice. She has demonstrated that the hyperactivity expressed by coloboma mice is the result of a deletion of the Snap gene. This gene encodes SNAP-25, a neuron-specific protein found in presynaptic nerve terminals that plays a major role in transmitter release. SNAP-25 is a component of the machinery essential for docking and holding synaptic vesicles at the presynaptic membrane in readiness for Ca2+ triggered transmitter exocytosis. Thus, it is though likely that defects in transmitter release cause by a reduction in SNAP- 25 expression results in the expression of hyperactivity. In fact, there appears to be a dopaminergic component to the hyperactivity as the applicant has also identified gross behavioral abnormalities in response to dopamimetics. It is hypothesized that abnormalities in vesicular function result in an increased concentration of cytosolic dopamine leading the unregulated nonexocytotic dopamine release ultimately expressed as hyperactivity. This proposal focuses on Ca2+ mediated transmitter release and dopaminergin function in coloboma mice to isolate the synaptic events giving rise to hyperactivity. The specific aims are: 1) To define abnormalities in vesicular neurotransmitter release. Individual release events will be recorded and drug-induced alterations in release assessed. 2) To assess the contribution of catecholaminergic neurotransmission to the generation of locomotor hyperactivity in coloboma mice. This contribution will be tested through a transgenic rescue experiment by replacing SNAP-25 in only catecholaminergic cells. 3) To identify neurochemical defects in vivo underlying hyperactivity in coloboma mice. These experiments will integrate the cellular defects identified in vitro with a functional analysis in vivo. 4) To determine the cellular mechanisms involved in hyperactivity using classical behavior pharmacology. Using drugs known to affect presynaptic dopamine terminals, including storage, synthesis and release, we will establish a direct link between dopamine terminal dysfunction and hyperactivity via this in vivo assay. The mouse mutant coloboma represents an unprecedented model in which to study the contributions of a single known gene to a complex multifactorial phenotype in humans which includes disorders such as attention deficit hyperactivity disorder and Tourette syndrome.