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信号的平衡对于动态平衡和 在缺氧时产生适当的反射。我们之前的研究建立了谷氨酸信号转导系统 孤束核(NTS)是颈动脉小体感觉整合的第一个中枢部位，在 慢性间歇性低氧。然而，GABA的具体贡献，它抵消了 谷氨酸信号，在被夸大的兴奋中是未知的。我们目前的目标是解决这一知识 GAP，并确定抑制性GABA信号对CIH后NTS过度兴奋的影响程度。 GABA信号受GABA释放、受体(GABARs)激活、氯(Cl-) 由氯-共转运体(NKCC1和KCC2)和星形细胞摄取GABA通过 运输商(GATS)。考虑到目前的文献和我们支持的初步数据，我们的主要观点 假说是，由于GABA信号的减弱，CIH使NTS的活性转移到过度兴奋的状态 GABA抑制和星形胶质细胞GAT活性升高。降低的GABA提示谷氨酸和GABA的平衡 信号，以及它们彼此之间的影响(即串扰)，朝着更大的激励最终增加 化学反射反应。目标1将确定脑出血患者GABA信号改变的程度以增加NTS 兴奋性。工作假设：减少GABA抑制增加NTS兴奋性和心肺功能 在CIH中的作用。脑出血患者由于谷氨酸上GABA释放减少或GABAR减少，GABA抑制作用减弱 神经元，改变Cl-转运和/或增强星形胶质细胞GAT。目标2将定义NTS GABA的大小 星形胶质细胞GABA转运体影响脑出血谷氨酸信号转导控制神经元和心肺功能 功能。工作假说：脑出血后GABA-Glu平衡向兴奋方向移动，部分原因是改变 GAT功能，最终增加NTS的兴奋性和心肺功能。在此应用程序中，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细胞操纵和分子生物学 最终破译生理功能。我们还将在转基因中使用AAV表达和Cre-技术 允许对从单个细胞到整个动物的GABA神经元进行特定记录和操作的大鼠。 每种技术都直接相互补充，实现了无与伦比的深度研究。加在一起，这些 技术允许对系统进行垂直研究和细致的细胞调查。在完成 建议的研究，我们期望确定NTS活性升高的意义和机制 在IH疾病中导致心肺异常的GABA信号减少。