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Frequency-dependent Modulation of Synaptic Transmission and Plasticity by pH

pH 值对突触传递和可塑性的频率依赖性调节

基本信息

批准号：
9324374
负责人：
MARK Oliver BEVENSEE
金额：
$ 18.38万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-08-15 至 2019-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9324374
关键词：
Acidosis Acids Acute Address Antibodies Astrocytes Axon Bathing Bicarbonates Brain Brain region Buffers Cell physiology Cerebellum Complex Coupled Couples Data Developmental Disabilities Disease Dyes Electrophysiology (science)Epilepsy Exhibits Extracellular Space Frequencies Gene Family Genes Hippocampus (Brain)Human Hypoxia Ischemia Ischemic Brain Injury Knockout Mice Knowledge Learning Link Long-Term Potentiation Measurement Measures Memory Mental Retardation Microelectrodes Modeling Molecular Mutation N-Methylaspartate Neurologic Deficit Neurons Output Pharmacology Physiological Physiology Play Population Presynaptic Terminals Prevention Pyramidal Cells Regulation Role Seizures Slice Synapses Synaptic Cleft Synaptic Transmission Synaptic plasticity Testing Viral Whole-Cell Recordings alkalinity base extracellular fluorescence imaging inhibitor/antagonist mind control neuronal excitability postsynaptic presynaptic presynaptic neurons receptor response restoration synaptic function therapeutic target tool transmission process

项目摘要

The regulation of intracellular pH (pHi) and extracellular pH (pHo) of brain is critical for optimizing neuronal excitability. Na-Coupled Bicarbonate Transporters (NCBTs) —particularly the astrocytic electrogenic Na/bicarbonate cotransporter NBCe1 that couples changes in pH with neuronal activity— are key regulators of brain pH. Despite the clear importance of pH regulation and the abundance of NBCe1 in brain, the role of NBCe1 and associated pH changes in modulating synaptic transmission and synaptic plasticity has not be identified. The current objective is to use molecular and pharmacological tools with electrophysiological approaches in brain-slice studies to investigate the role of NBCe1 and associated pH changes in modulating hippocampal synaptic function. Aim 1 is to address the hypothesis that NBCe1 dampens basal, low-frequency synaptic transmission. A combination of extracellular and whole-cell recordings in CA1 of acute hippocampal slices from wild-type and NBCe1 knockout (KO) mice will be used to investigate the role of NBCe1 in regulating synaptic transmission and spiking in hippocampal CA1 in response to low-frequency (0.1 Hz) extracellular stimulation. The effects of NBCe1 inhibitors (S0859 and a function blocking L3 antibody), a function stimulating L4 antibody, and viral restoration of NBCe1 into astrocytes in NBCe1 KO mice will be determined. pH-sensitive microelectrodes and dyes will be used to examine associated changes in pHo, as well as the pH of astrocytes and presynaptic terminals to test the hypothesis that inhibiting NBCe1 stimulates basal synaptic transmission by enhancing the extracellular alkaline shift (established conventional model). Aim 2 is to address the hypothesis that NBCe1 enhances high-frequency synaptic transmission and long-term plasticity. The molecular and pharmacological tools and approaches described for Aim 1 will be used to examine excitatory synaptic responses, but in response to high-frequency (50 Hz) extracellular stimulation. pH measurements will be made in the extracellular space, astrocytes, and presynaptic nerve terminals to test the hypothesis that NBCe1 stimulation of high-frequency synaptic transmission and long-term potentiation (LTP) involves dampening of the activity-evoked presynaptic pHi decrease (new mechanism). Underlying mechanisms such as pre- vs postsynaptic responses and the role of specific receptors will be evaluated for both Aims. Results will reveal that NBCe1 is a physiologically important acid-base transporter that modulates synaptic transmission and LTP through changes in pH that are dependent on frequency stimulation. The results will contribute to our understanding of NBCe1 and associated pH changes in neuronal activity, seizures, ischemia, and hypoxia.

脑细胞内pH(Phi)和细胞外pH(Pho)的调节是优化神经元的关键兴奋性。钠偶联碳酸氢盐转运体(NCBT)--尤其是星形胶质细胞的生电作用钠/碳酸氢盐共转运体NBCe1将pH的变化与神经元活动结合在一起-是大脑的酸碱度。尽管pH调节和NBCe1在大脑中的丰富存在具有明显的重要性，但其作用 NBCe1及其相关pH变化在调节突触传递和突触可塑性中的作用尚未见报道确认身份。目前的目标是将分子和药理学工具用于电生理脑片研究中NBCe1及其相关的pH变化在调节中的作用海马区突触功能。目标1是解决NBCe1抑制基础、低频的假设突触传递。急性海马区CA1区细胞外和全细胞记录相结合野生型和NBCe1基因敲除(KO)小鼠的切片将被用来研究NBCe1在调节低频(0.1 Hz)细胞外刺激对海马CA1区突触传递和放电的影响刺激。NBCe1抑制剂(S0859和一种功能阻断L3抗体)的作用在NBCe1KO小鼠体内，检测NBCe1对星形胶质细胞的L4抗体的刺激作用和病毒修复作用。 PH值敏感的微电极和染料将被用来检测pho的相关变化，以及星形胶质细胞和突触前终末验证抑制NBCe1刺激基础突触的假说通过增强细胞外碱性转移进行传递(已建立常规模型)。目标2是解决 NBCe1增强高频突触传递和长期可塑性的假说。这个将使用为目标1描述的分子和药理学工具和方法来检查兴奋性突触反应，但对高频(50赫兹)细胞外刺激的反应。PH值测量将在细胞外空间、星形胶质细胞和突触前神经末梢中进行实验，以检验这一假设 NBCe1刺激高频突触传递和长时程增强涉及抑制活动诱发的突触前PHi下降(新机制)。潜在的机制，如将评估突触前和突触后的反应以及特定受体的作用以达到这两个目的。结果将揭示NBCe1是一种调节突触传递的重要生理酸碱转运体和LTP通过依赖于频率刺激的pH变化来实现。结果将有助于我们的了解NBCe1及其相关的pH变化在神经元活动、癫痫发作、缺血和缺氧中的作用。