GABA signaling in the nTS and cardiorespiratory responses to hypoxia

nTS 中的 GABA 信号传导和缺氧心肺反应

• 批准号: 10558915
• 负责人: David Douglas Kline
• 金额: $ 70.34万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-10 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10558915
• 关键词: Address; Animal Model; Animals; Astrocytes; Attenuated; Brain; Brain Stem; Breathing; Cardiovascular system; Carotid Body; Cell Nucleus; Cells; Chlorides; Chronic; Complement; Data; Dependovirus; Disease; Electrophysiology (science); Epilepsy; Equilibrium; Exhibits; Exposure to; Familial Dysautonomia; Foundations; Glutamate Transporter; Glutamates; Goals; Homeostasis; Hypertension; Hypoxia; Investigation; Knowledge; Literature; Mediating; Modeling; Molecular Biology; Morbidity - disease rate; Neurons; Nucleus solitarius; Obstructive Sleep Apnea; Pathway interactions; Patients; Peripheral; Physiological; Process; Rat Transgene; Rattus; Receptor Activation; Reflex action; Research; Rett Syndrome; Sensory; Signal Transduction; Site; Synapses; System; Techniques; Technology; designer receptors exclusively activated by designer drugs; falls; gamma-Aminobutyric Acid; glutamatergic signaling; live cell imaging; mortality; normoxia; novel therapeutic intervention; rational design; receptor; respiratory; response; reuptake; sensory integration; symporter; uptake

Maintaining the balance of excitatory glutamate and inhibitory GABA signaling is critical for homeostasis and generating proper reflexes in response to hypoxia. Our previous studies established glutamate signaling in the nucleus tractus solitarii (nTS), the first central site for carotid body sensory integration, is exaggerated after chronic intermittent hypoxia (CIH). However, the specific contribution of GABA, which counter-balances glutamate signaling, in the exaggerated excitation is unknown. Our current goal is to address this knowledge gap and determine the extent that inhibitory GABA signaling contributes to overexcitation of the nTS after CIH. GABA signaling is controlled or modulated by GABA release, receptor (GABARs) activation, the chloride (Cl-) equilibrium potential that is set by Cl- co-transporters (NKCC1 and KCC2), and astrocytic GABA uptake via transporters (GATs). Given the present literature and our supporting preliminary data, our overarching hypothesis is that CIH shifts nTS activity to an overexcited state due to attenuated GABA signaling via reduced GABA inhibition and increased astrocyte GAT activity. Reduced GABA tips the balance of Glu and GABA signaling, and their influence on each other (i.e., cross-talk), towards greater excitation to ultimately increase chemoreflex responses. Aim 1 will determine the extent GABA signaling is altered in CIH to increase nTS excitability. Working hypothesis: Reduced GABA inhibition increases nTS excitability and cardiorespiratory function in CIH. GABA inhibition is attenuated in CIH due to reduced GABA release or GABARs on Glu neurons, altered Cl- transport and/or augmented astrocyte GAT. Aim 2 will define the magnitude nTS GABA and astrocyte GABA transporters influence Glu signaling in CIH to control neuronal and cardiorespiratory function. Working hypothesis: GABA-Glu balance is shifted towards excitation after CIH, in part due to altered GAT function, to ultimately to increase nTS excitability and cardiorespiratory function. In this application, we will utilize a multi-faceted, synergistic and integrative approach. We will use a range of techniques including single cell electrophysiology, live-cell imaging, DREADD cellular manipulation and molecular biology to ultimately decipher physiological function. We will also use AAV expression and Cre-technology in transgenic rats that allows specific recording and manipulation in GABA neurons from the single cell to whole animal. Each technique directly complements the other, allowing an unparalleled depth of study. Together, these techniques allow the vertical study of the system and meticulous cellular investigation. Upon completion of the proposed research, we expect to identify the significance and mechanisms of elevated nTS activity due to reduced GABA signaling that result in cardiorespiratory abnormalities in IH diseases.

维持兴奋性谷氨酸和抑制性 GABA 信号的平衡对于体内稳态和 产生适当的反应以应对缺氧。我们之前的研究证实了谷氨酸信号传导 孤束核（nTS）是颈动脉体感觉统合的第一个中心部位，在 慢性间歇性缺氧（CIH）。然而，GABA 的具体贡献抵消了 谷氨酸信号传导，在夸大的兴奋中是未知的。我们当前的目标是解决这些知识 间隙并确定抑制性 GABA 信号传导导致 CI​​H 后 nTS 过度兴奋的程度。 GABA 信号传导受 GABA 释放、受体 (GABAR) 激活、氯 (Cl-) 控制或调节 由 Cl- 协同转运蛋白（NKCC1 和 KCC2）设定的平衡电位，以及星形胶质细胞 GABA 的摄取 运输者（GAT）。鉴于目前的文献和我们支持的初步数据，我们的总体 假设 CIH 通过减少 GABA 信号传导而将 nTS 活性转变为过度兴奋状态 GABA 抑制并增加星形胶质细胞 GAT 活性。减少 GABA 平衡 Glu 和 GABA 信号传导及其相互影响（即串扰），以产生更大的兴奋，最终增加 化学反射反应。目标 1 将确定 CIH 中 GABA 信号传导的改变程度以增加 nTS 兴奋性。工作假设：GABA 抑制减少会增加 nTS 兴奋性和心肺功能 在 CIH 中发挥作用。由于 GABA 释放或 Glu 上的 GABAR 减少，GABA 抑制在 CIH 中减弱 神经元、Cl-转运改变和/或星形胶质细胞 GAT 增强。目标 2 将定义 nTS GABA 的震级 星形胶质细胞 GABA 转运蛋白影响 CIH 中的 Glu 信号传导以控制神经元和心肺功能 功能。工作假设：CIH 后 GABA-Glu 平衡向兴奋方向转变，部分原因是由于变化 GAT功能，最终提高nTS兴奋性和心肺功能。在这个应用程序中，我们 将采用多方面、协同和综合的方法。我们将使用一系列技术，包括 单细胞电生理学、活细胞成像、DREADD 细胞操作和分子生物学 最终破译生理功能。我们还将使用AAV表达和Cre-技术进行转基因 允许对从单细胞到整个动物的 GABA 神经元进行特定记录和操作的大鼠。 每种技术都直接补充另一种技术，从而实现无与伦比的研究深度。在一起，这些 技术允许对系统进行垂直研究和细致的细胞研究。完成后 拟议的研究，我们希望确定 nTS 活性升高的意义和机制 GABA 信号传导减少，导致 IH 疾病中的心肺异常。