TETRAHYDROBIOPTERIN BIOSYSTHESIS BY DOPAMINE NEURONS

四氢生物蝶呤是酪氨酸和色氨酸的必需辅助因子 羟化酶，一元胺合成中的限速酶 神经递质多巴胺去甲肾上腺素和血清素。 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酶 精氨酸。人类遗传性细胞类型特异性缺陷 单胺神经传递的存在是遗传的直接结果 四氢生物蝶呤合成的缺陷。是否缺乏神经元 一氧化氮的产生可能是由于类似的遗传缺陷， 被确定。此更新申请概述了一系列广泛的 在完整动物和组织培养中进行的实验， 旨在进一步了解四氢生物蝶呤的作用 在控制一元胺和一氧化氮的合成方面。具体目标1 表征四氢生物蝶呤生物合成酶的基因表达 在使用原位杂交鉴定的单胺神经元内， 免疫放射自显影技术。预计这些研究将 产生关于这些酶分布的重要新信息 在单胺神经元群体之间。具体目标2调查 单胺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定量， 在用本发明的化合物激发后，代表性的单胺细胞群 单胺消耗药利血平含单胺神经元 维持在组织培养将用于研究第二个 信使系统参与的长期和短期的调节 四氢生物蝶呤合成特异性目标3表征基因 四氢生物蝶呤生物合成酶在硝酸盐中的表达 原位杂交和免疫放射自显影 技术，并应产生重要的新信息的分布 这些酶在一氧化氮神经元群体中的作用， 一氧化氮合酶的不同同种型。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的四氢生物蝶呤合成， 将解决四氢生物蝶呤调节 神经元一氧化氮的产生。 全面了解控制 四氢生物蝶呤的生物合成在特定人群中 单胺和一氧化氮神经元应该有助于促进对 假设与这些神经递质有关的临床疾病。

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.