Neurotransmitter metabolism in intermittent hypoxia

描述（由申请人提供）： 该提案的总体目标是广泛定义翻译后 与酶活性变化相关的机制调节了 慢性间歇性缺氧（CIH）导致神经递质的生物合成。 与CIH相关的机制有助于各种生理和 病理生理条件，如睡眠呼吸暂停，并导致发展 高血压神经递质，如儿茶酚胺，γ-氨基丁酸 酸性和酰胺化神经肽参与心肺功能的调节 应答该提案检验了以下总体假设： 间歇性低氧改变化学传入神经递质水平 通过影响与合成相关的酶的活性， 神经递质通过翻译后修饰。假设将 通过关注酪氨酸羟化酶（TH）、谷氨酸脱羧酶 (GAD)和肽酰甘氨酸α-酰胺化单加氧酶（PAM）， 酶的生物合成中的儿茶酚胺，GABA和酰胺化 神经肽类。具体目标1中的实验将比较 结果：①大鼠脑内儿茶酚胺（去甲肾上腺素、多巴胺和5-羟色胺）含量的变化， 羟色胺）和TH活性。此外，它将测试 假设CIH诱导TH磷酸化，从而改变酶 活动TH酶学性质的潜在改变将是 考察在具体目标2下提议的研究侧重于以下机制： CIH改变GAD的活性。具体而言， 建议的研究是确定辅因子亲和力的变化， 磷酸化和去磷酸化反应。在具体目标3中， CIH对含Cu 2+的金属中心的氧化还原化学的影响， PAM翻译后内切蛋白水解修饰将 研究了实验将在暴露于交替的 缺氧和常氧循环的规定时间和大鼠暴露于 类似持续时间的室内空气将用作对照。组织相关 化学传入通路如脑干和颈动脉体将被 研究了预计， 这个项目可以提供重要的新信息，并扩大我们的 了解间歇性缺氧对与以下相关的酶的影响： 化学传入通路中的神经递质代谢。的信息 将有可能发现新的治疗靶点 用于干预与复发性间歇性 缺氧

DESCRIPTION (provided by applicant): The overall objective of the proposal is to broadly define post-translational mechanisms associated with changes in the activity of enzymes regulate the biosynthesis of neurotransmitters by chronic intermittent hypoxia (CIH). Mechanisms associated with CIH contribute to various physiological and pathophysiological conditions such as sleep apnea and leads to the development of hypertension. Neurotransmitters such as catecholamines, gamma-aminobutyric acid and amidated neuropeptides involve in the modulation of cardio-respiratory responses. The proposal tests the overall hypothesis that intermittent hypoxia alters neurotransmitter levels in the chemoafferent pathway by affecting the activity of enzymes associated with the synthesis of neurotransmitters via post-translational modifications. The hypothesis will be tested by focusing on tyrosine hydroxylase (TH), glutamate decarboxylase (GAD) and peptidylglycine alpha-amidating monooxygenase (PAM) the rate-limiting enzymes in the biosynthesis of catecholamines, GABA and amidated neuropeptides respectively. The experiments in specific aim 1 will compare the changes in the content of catecholamines (norepinephrine, dopamine and 5- hydroxytryptamine) and the activity of TH by CIH. Further, it will test the hypothesis that CIH induces phosphorylation of TH, thereby altering the enzyme activity. Potential alteration in enzymological properties of TH will be examined. Studies proposed under specific aim 2 focus on the mechanisms by which the activity of GAD is altered by CIH. Specifically, the aims of the proposed studies are to define changes in cofactor affinity and phosphorylation and dephosphorylation reactions of GAD. In specific aim 3, the effects of CIH on the redox chemistry of metal centers containing Cu2+ and the post-translational endoproteolytic modification of PAM will be investigated. Experiments will be performed in rats exposed to alternating cycles of hypoxia and normoxia for defined periods of time and rats exposed to similar duration of room air will serve as control. Tissues associated with the chemoafferent pathway such as brainstem, and carotid body will be investigated. It is anticipated that the results from studies proposed in this project may provide important new information and broaden our understanding of the effects of episodic hypoxia on enzymes associated with neurotransmitter metabolism in the chemoafferent pathway. The information from these studies will have the potential to identify new therapeutic targets for the intervention of sleep disorders associated with recurrent intermittent hypoxia.