TETRAHYDROBIOPTERIN BIOSYSTHESIS BY DOPAMINE NEURONS

四氢生物蝶呤是酪氨酸和色氨酸的重要辅因子 羟基酶--单胺合成中的限速酶 神经递质多巴胺、去甲肾上腺素和5-羟色胺。 四氢生物蝶呤也是一氧化氮家族所必需的 合成气态神经递质一氧化氮的合成酶 来自精氨酸。人类遗传性细胞类型特异性缺陷 单胺类神经传递的存在是遗传的直接结果 四氢生物蝶呤合成中的缺陷。神经元的缺陷是否 一氧化氮的产生可以由类似的遗传缺陷引起 要下定决心。此续订申请概述了一系列广泛的 在完整的动物和组织培养中进行的实验 旨在加深我们对四氢生物蝶呤作用的理解 控制单胺和一氧化氮的合成。具体目标1 四氢生物蝶呤生物合成酶的基因表达特征 用原位杂交法和 免疫放射自显影技术。预计这些研究将 产生关于这些酶的分布的重要新信息 在单胺类神经元的种群中。特定目标2调查 单胺类神经元内四氢生物蝶呤合成的调节。 基因表达的变化将在神经元中进行量化 具有代表性的单胺类细胞群在与 单胺消耗药物利血平。含单胺神经元 保持在组织培养中将被用来研究第二 参与长期和短期调节的信使系统 四氢生物蝶呤合成。特异靶3基因特征 四氢生物蝶呤生物合成酶在一氧化氮中的表达 氧化神经元的原位杂交和免疫放射自显影 技术，并应产生有关分发的重要新信息 这些酶在含有以下物质的一氧化氮神经元群体中 不同类型的一氧化氮合酶。具体目标4研究 四氢生物蝶呤合成的短期和长期调节 组织中维持的不同数量的一氧化氮神经元 文化。这些研究将有助于确定细胞机制 调节一氧化氮神经元内四氢生物蝶呤的合成 将解决四氢生物蝶呤潜在的调节能力 神经元型一氧化氮的产生。对控制的总体理解 四氢生物蝶呤在特定种群中的生物合成 单胺和一氧化氮神经元应该有助于促进对 临床疾病被认为与这些神经递质有关。

Tetrahydrobiopterin is the essential cofactor for tyrosine and tryptophan hydroxylase, the rate-limiting enzymes in the synthesis of the monoamine neurotransmitters dopamine, norepinephrine and serotonin. Tetrahydrobiopterin is also required by the family of nitric oxide synthases for the synthesis of the gaseous neurotransmitter nitric oxide from arginine. Inherited cell-type specific deficiencies in human monoamine neurotransmission exist that are the direct result of genetic defects in tetrahydrobiopterin synthesis. whether deficiencies in neuronal nitric oxide production can result from similar genetic defects remains to be determined. This renewal application outlines a broad series of experiments performed in the intact animal and in tissue culture that are designed to further our understanding of the role of tetrahydrobiopterin in the control of monoamine and nitric oxide synthesis. Specific Aim 1 characterizes gene expression for tetrahydrobiopterin biosynthetic enzymes within identified monoamine neurons using in situ hybridization and immunoautoradiographic techniques. It is expected that these studies will generate important new information on the distribution of these enzymes across populations of monoamine neurons. Specific Aim 2 investigates the regulation of tetrahydrobiopterin synthesis within monoamine neurons. Changes in gene expression will be quantitated in neurons from representative monoamine cell groups following a challenge with the monoamine-depleting drug reserpine. Monoamine-containing neurons maintained in tissue culture will be used to investigate the second messenger systems involved in the long and short-term regulation of tetrahydrobiopterin synthesis. Specific Aim 3 characterizes gene expression for tetrahydrobiopterin biosynthetic enzymes within nitric oxide neurons using in situ hybridization and immunoautoradiographic techniques and should yield important new information on the distribution of these enzymes across populations of nitric oxide neurons that contain different isotypes of nitric oxide synthase. Specific Aim 4 studies the short and long term regulation of tetrahydrobiopterin synthesis within two different populations of nitric oxide neurons maintained in tissue culture. These studies will help to define the cellular mechanisms that regulate tetrahydrobiopterin synthesis within nitric oxide neurons and will address the potential ability of tetrahydrobiopterin to modulate neuronal nitric oxide production. An overall understanding of the control of tetrahydrobiopterin biosynthesis within specific populations of monoamine and nitric oxide neurons should help facilitate research on clinical disorders hypothesized to involve these neurotransmitters.