CATECHOLAMINERGIC NEURON PLASTICITY IN AGED BRAIN

的形态和功能可塑性的能力 老年大鼠脑内的儿茶酚胺(CA)能神经元将用 作为一个模型系统，一个接触和调节靶点的氨基能区 视上核(SON)中的分泌神经元投射到 神经垂体和分泌加压素(VP)。这些传入神经 含有去甲肾上腺素(NE)的轴突将被神经外科手术切断， 要么在儿子的终结点附近，要么在他们的牢房附近 起源于腹侧中脑。病变部位和靶点 核团SON将被检查新纤维的生长和CA的神经再支配， 将通过显微荧光定量技术对其进行评估 内源性CA组织荧光和Son CA水平的生化测定 采用高效液相色谱分离。定性评估将 包括顺行道追踪。靶点的功能恢复 神经元将通过免疫细胞化学染色的神经物理素和 VP、血浆VP放射免疫测定法和水平衡监测 (饮酒量、尿量和渗透压)。可能做出的贡献 SON血管周围交感神经支配对神经再支配的影响 模式将通过联合颈上神经节切除术和 每一项神经外科病变，并同步进行评估 血管系统和末端荧光的可视化，以及 生化和微量荧光分光光度法定量测定靶标中的CA。 初步研究表明，相当大的形态能力 再生保留在年老的大脑中；拟议的项目将 提供相关的解剖和功能评估。

The capacity for morphological and functional plasticity of catecholaminergic (CA) neurons in aged rat brain will be evaluated, using as a model system an aminergic tract which contacts and regulates target secretory neurons in the supraoptic nucleus (SON) which project to the neurohypophysis and secrete vasopressin (VP). These afferent norepinephrine (NE) containing axons will be neurosurgically severed, either near their point of termination at the SON, or near their cells of origin in the ventral mesencephalon. The lesion sites and the target nucleus, SON, will be examined for new fiber growth and CA reinnervation, which will be evaluated by microspectrofluorometric quantitation of endogenous CA histofluorescence, and biochemical measure of SON CA levels by high performance liquid chromatography. Qualitative assessment will include anterograde tract tracing. Functional restoration in the target neurons will be assessed by immunocytochemical staining of neurophysin and VP, radioimmunoassay of plasma VP, and monitoring of water balance (drinking, and urine volume and osmolality). The possible contribution of peripheral sympathetic innervation of SON vasculature to the reinnervation pattern will be tested by combining superior cervical ganglionectomy with each of the neurosurgical lesions, and evaluation by simultaneous visualization of vasculature and terminal fluorescence, as well as biochemical and microspectrofluorometric quantitation of CA in the target. Preliminary studies indicate that a considerable capacity for morphological regeneration is retained in the aged brain; the proposed project will provide a correlative anatomical and functional assessment.