NPY AND ATP COTRANMISSION IN CHROMAFFIN CELLS

嗜铬细胞中的 NPY 和 ATP 协同传输

基本信息

批准号：
6637531
负责人：
TERRY D HEXUM
金额：
$ 22.37万
依托单位：
UNIVERSITY OF NEBRASKA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-03-07 至 2004-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6637531
关键词：
adenosine triphosphate animal tissue calcium flux calcium indicator catecholamines chromaffin cells high performance liquid chromatography immunoprecipitation inositol phosphates neural transmission neuropeptide Y neurotransmitter biosynthesis northern blottings tissue /cell culture tyrosine 3 monooxygenase western blottings

项目摘要

Neuropeptide Y (NPY) exerts a variety of effects including increased blood pressure and food intake and decreased anxiety. The increase in blood pressure occurs in conjunction with co- existing transmitters such as ATP and norepinephrine. The long- term objective of research in this laboratory is to reveal the mechanism(s) by which neuropeptides produce physiological changes. Bovine chromaffin cells provide a useful model with which to study neuropeptide action since these cells synthesize and secrete NPY in response to stimulation with nicotine. The goal of the current proposal is to gain insight into the physiological role of NPY as a co-transmitter with ATP. NPY binds to chromaffin cell receptors of the Y1 subtype and inhibits forskolin stimulated adenylate cyclase activity. Our preliminary data show that it does not alter chromaffin cell intracellular Ca2+ concentration ([Ca2+]i) or inositol phosphate formation unless ATP is added to culture media along with NPY. NPY can significantly enhance both the ATP stimulated increase in inositol phosphate formation and [Ca2+]i. The chromaffin cell response to this action is unknown but may include the regulation of neurotransmitter synthesis since increased inositol phosphate formation and [Ca2+]i could have been shown to result in increased tyrosine hydroxylase synthesis. In addition, an increase in [Ca2+]i could stimulate tyrosine hydroxylase activity acutely due to increased enzyme phosphorylation mediated by CaM kinase II. Our hypothesis is that NPY and ATP are co- transmitters in chormaffin cells that serve to increase [Ca2+]i by increasing inositol phosphate formation with the resultant effect of increased catecholamine biosynthesis. The specific aims are to characterize the enhancing effect of NPY on ATP- stimulated inositol phosphate formation, identify the ATP receptor subtype mediating the stimulation of InsP formation and increased [Ca2+]i, determine the specificity of the ATP potentiating effect of NPY and discover the response of the chromaffin cell to increased intracellular Ca2+. These studies will further our understanding of the physiological role of neuropeptides and their involvement in co-transmission. Information will be provided which may lead to improved therapy of diseases particularly involving aberrations in transmission by catecholamines e.g., epilepsy, anorexia, alcoholism, and hypertension.

神经肽 Y (NPY) 具有多种作用，包括增加血压和食物摄入量以及减少焦虑。血压升高与 ATP 和去甲肾上腺素等共存递质有关。该实验室研究的长期目标是揭示神经肽产生生理变化的机制。牛嗜铬细胞提供了一个有用的模型来研究神经肽的作用，因为这些细胞响应尼古丁的刺激而合成和分泌 NPY。当前提案的目标是深入了解 NPY 作为 ATP 共同递质的生理作用。 NPY 与 Y1 亚型的嗜铬细胞受体结合，并抑制毛喉素刺激的腺苷酸环化酶活性。我们的初步数据表明，除非将 ATP 与 NPY 一起添加到培养基中，否则它不会改变嗜铬细胞胞内 Ca2+ 浓度 ([Ca2+]i) 或磷酸肌醇的形成。 NPY 可以显着增强 ATP 刺激的磷酸肌醇形成和 [Ca2+]i 的增加。嗜铬细胞对此作用的反应尚不清楚，但可能包括神经递质合成的调节，因为磷酸肌醇形成的增加和[Ca2+]i可能已被证明会导致酪氨酸羟化酶合成的增加。此外，由于 CaM 激酶 II 介导的酶磷酸化增加，[Ca2+]i 的增加可以急剧刺激酪氨酸羟化酶活性。我们的假设是，NPY 和 ATP 是嗜铬细胞中的共同递质，通过增加磷酸肌醇的形成来增加 [Ca2+]i，从而增加儿茶酚胺生物合成。具体目的是表征 NPY 对 ATP 刺激的磷酸肌醇形成的增强作用，鉴定介导 InsP 形成刺激和 [Ca2+]i 增加的 ATP 受体亚型，确定 NPY ATP 增强作用的特异性，并发现嗜铬细胞对细胞内 Ca2+ 增加的反应。这些研究将进一步加深我们对神经肽的生理作用及其参与共同传播的理解。将提供可能导致改善疾病治疗的信息，特别是涉及儿茶酚胺传播异常的疾病，例如癫痫、厌食症、酗酒和高血压。