GROWTH FACTORS INFLUENCE STROKE RECOVERY

最近的数据表明，局灶性脑缺血会导致神经元死亡， 至少在一定程度上，是通过引发“致命的连锁反应”， 包括兴奋性氨基酸(EaAs)的释放，从而导致大量 CA2进入细胞，并由此激活细胞内 蛋白水解酶和核酸酶与有毒自由基和硝酸根的产生 氧化物(NO)。碱性成纤维细胞生长因子是一种神经营养因子 促进神经元在体外存活的多肽，并保护 培养的神经元可以抵抗一些侮辱和毒素，包括 缺氧，低血糖，内源性氨基酸，钙离子载体，自由基和一氧化氮。在……里面 初步研究发现，外源性给予bFGF可减少 大鼠局灶性脑缺血模型的脑梗塞体积 新生大鼠在体。在建议的研究中，我们会进一步探讨 碱性成纤维细胞生长因子对局灶性脑缺血的神经保护作用及其机制 这些研究包括：(1)进一步研究剂量、时机和路线 碱性成纤维细胞生长因子在成熟和新生大鼠脑缺血模型中的应用 大鼠，以及比较碱性成纤维细胞生长因子与其他特征的 生长因子，(2)外源生物分布研究-- 碱性成纤维细胞生长因子及其受体的密度和定位 缺血后，(3)候选“神经保护”调节机制的研究 外源性碱性成纤维细胞生长因子对基因表达的影响； 脑血管系统。预计这些研究将带来新的 局灶性脑损伤后神经元存活的分子机制 缺血症。 P50NS108280032 这项提议利用分子遗传学方法来产生和 缺乏神经元型一氧化氮合酶的动物模型的特征 (Nos)基因。一氧化氮(NO)是一种由神经元产生的气体， 体内的内皮细胞、神经胶质细胞和其他细胞。它有 不同寻常的特性使它非常适合作为空间信使在 细胞与细胞的相互作用。作为一种气体，它可以自由扩散 膜。它与血红素结合并被血红素灭活，限制了它的一半- 生命只有几秒钟。在神经系统中，一氧化氮被牵连到 在生理和毒性反应中建立突触可塑性 兴奋性神经递质，并可能在缺血性损伤中发挥作用 死于脑血管疾病。在血管系统中，一氧化氮负责 内皮衍生的松弛因子(EDRF)活性，并可能是 参与静息血管张力以及对血管的反应 脑血管系统和血管内皮损伤中的介质和内皮损伤 在外周血管系统中。 我们建议建立和鉴定神经元型一氧化氮合酶的小鼠 基因被选择性地打乱或“敲除”，这里指的是 作为KN小鼠(基因敲除，神经元型一氧化氮合酶)。我们实验室正在进行的工作是 致力于小鼠的平行发育，其中血管一氧化氮合酶 基因被敲除，KV小鼠(敲除，血管一氧化氮合酶)。我们建议 描述KN和KV小鼠的表型 神经解剖学和脑循环。我们希望了解一下 允许KN和KV小鼠发育和存活的代偿机制 在缺乏内源性神经元和血管一氧化氮合酶基因的情况下。这 Project还将维持KN和KV小鼠的繁殖群体，以 为项目#1B提供足够数量的MICE。人们希望， 这些实验将有助于我们对分子的理解 脑血管张力在健康和疾病中的作用机制。

Recent data indicate that focal cerebral ischemia causes neural death, at least in part, through initiation of a "lethal cascade," which includes release of excitatory amino acids (EAAs) with consequent massive Ca2+ entry into cells, and resulting activation of intracellular proteases and nucleases, and generation of toxic free radicals and nitric oxide (NO). Basic fibroblast growth factor (bFGF) is a neuronotrophic polypeptide that promotes neuronal survival in vitro, and protects cultured neurons against a number of insults and toxins, including anoxia, hypoglycemia, EAAs, Ca2+ ionophore, free radicals, and NO. In preliminary studies, we found that exogenously-administered bFGF reduced infarct volume in models of focal cerebral ischemia in mature and neonatal rats in vivo. In the proposed studies, we will further explore the phenomenon and mechanism of bFGF neuroprotection in focal ischemia. These studies include: (1) further study of the dose, timing, and route of administration of bFGF in models of ischemia in mature and neonatal rats, as well as comparison of the effects of bFGF to other characterized growth factors, (2) studies of the biodistribution of exogenously- administered bFGF, and the density and localization of bFGF receptors after ischemia, (3) studies of regulation of candidate "neuroprotective" genes by exogenous bFGF, and (4) studies of the effects of bFGF on the cerebral vasculature. It is expected that these studies will shed new light on molecular mechanisms supporting neuronal survival after focal ischemia. P50NS108280032 This proposal utilizes a molecular genetics approach to generate and characterize animal models that lack the neuronal nitric oxide synthase (NOS) gene. Nitric oxide (NO) is a gas that is made by neurons, endothelial cells, glial cells, and other cells in the body. It has unusual properties that make it well suited to be a spatial messenger in cell-cell interactions. As a gas, it is freely diffusible across membranes. It binds to and is inactivated by heme, limiting its half- life to seconds. In the nervous system, NO has been implicated in establishing synaptic plasticity, in the physiologic and toxic response to excitatory neurotransmitters, and may play a role in ischemic damage from cerebrovascular disease. In the vasculature, NO is responsible for endothelial-derived relaxing factor (EDRF) activity, and is likely to be involved in resting blood vessel tone, as well as responses to vascular mediators and endothelial injury, in the cerebrovasculature as well as in the peripheral vasculature. We propose to develop and characterize mice in which the neuronal NOS gene has been selectively disrupted or "knocked-out," herein referred to as KN mice (knock-out, neuronal NOS). Ongoing work in our laboratory is devoted to the parallel development of mice in which the vascular NOS gene is knocked-out, KV mice (knock-out, vascular NOS). We propose to characterize the phenotype of the KN and KV mice, in terms of neuroanatomy and cerebral circulation. We hope to learn about the compensatory mechanisms that allow KN and KV mice to develop and survive in the absence of the endogenous neuronal and vascular NOS genes. This project will also maintain breeding colonies of KN and KV mice, in order to provide sufficient numbers of mice for project #1B. It is hoped that these experiments will contribute to our understanding of the molecular mechanisms involved in cerebrovascular tone in health and disease.