Abstract：
OBJECTIVE: This study sought to elucidate the primary ATP-dependent mechanisms involved in clearing cytosolic Ca2+ in neurons and determine the predominant ATP-generating pathway-glycolysis or tricarboxylic acid cycle/oxidative phosphorylation (TCA/OxPhos)-associated with these mechanisms in hippocampal pyramidal neurons.
METHODS: Our investigation involved evaluating basal Ca2+ levels and analyzing the kinetic characteristics of evoked neuronal Ca2+ transients after selectively combined the inhibition/blockade of key ATP-dependent mechanisms with the suppression of either TCA/OxPhos or glycolytic ATP sources.
RESULTS: Our findings unveiled that the plasma membrane Ca2+ ATPase (PMCA) serves as the principal ATP-dependent mechanism for clearance cytosolic Ca2+ in hippocampal pyramidal neurons, both during rest and neuronal activity. Remarkably, during cellular activity, PMCA relies on ATP derived from glycolysis, challenging the traditional notion of neuronal reliance on TCA/OxPhos for ATP. Other mechanisms for Ca2+ clearance in pyramidal neurons, such as SERCA and NCX, appear to be dependent on TCA/OxPhos. Interestingly, at rest, the ATP required to fuel PMCA and SERCA, the two main mechanisms to keep resting Ca2+, seems to originate from a source other than glycolysis or the TCA/OxPhos.
CONCLUSIONS: These findings underscore the vital role of glycolysis in bolstering PMCA neuronal function to uphold Ca2+ homeostasis. Moreover, they elucidate the varying dependencies of cytoplasmic Ca2+ clearance mechanisms on distinct energy sources for their operation.
METHODS: Our investigation involved evaluating basal Ca2+ levels and analyzing the kinetic characteristics of evoked neuronal Ca2+ transients after selectively combined the inhibition/blockade of key ATP-dependent mechanisms with the suppression of either TCA/OxPhos or glycolytic ATP sources.
RESULTS: Our findings unveiled that the plasma membrane Ca2+ ATPase (PMCA) serves as the principal ATP-dependent mechanism for clearance cytosolic Ca2+ in hippocampal pyramidal neurons, both during rest and neuronal activity. Remarkably, during cellular activity, PMCA relies on ATP derived from glycolysis, challenging the traditional notion of neuronal reliance on TCA/OxPhos for ATP. Other mechanisms for Ca2+ clearance in pyramidal neurons, such as SERCA and NCX, appear to be dependent on TCA/OxPhos. Interestingly, at rest, the ATP required to fuel PMCA and SERCA, the two main mechanisms to keep resting Ca2+, seems to originate from a source other than glycolysis or the TCA/OxPhos.
CONCLUSIONS: These findings underscore the vital role of glycolysis in bolstering PMCA neuronal function to uphold Ca2+ homeostasis. Moreover, they elucidate the varying dependencies of cytoplasmic Ca2+ clearance mechanisms on distinct energy sources for their operation.
摘要：
目的：本研究旨在阐明参与清除神经元胞质Ca2+的主要ATP依赖性机制，并确定与海马锥体神经元这些机制相关的主要ATP生成途径-糖酵解或三羧酸循环/氧化磷酸化（TCA/OxPhos）。
方法：我们的研究涉及评估基础Ca2+水平，并分析选择性结合抑制/阻断关键ATP依赖性机制和抑制TCA/OxPhos或糖酵解ATP来源后诱发神经元Ca2+瞬变的动力学特征。
结果：我们的发现揭示了质膜Ca2ATPase（PMCA）是清除海马锥体神经元中胞质Ca2的主要ATP依赖性机制，在休息和神经元活动期间。值得注意的是,在细胞活动期间，PMCA依赖于糖酵解的ATP，挑战神经元依赖TCA/OxPhos获取ATP的传统观念。锥体神经元中Ca2+清除的其他机制，如SERCA和NCX，似乎依赖于TCA/OxPhos。有趣的是,在休息时,为PMCA和SERCA提供燃料所需的ATP，保持静息Ca2+的两种主要机制，似乎起源于糖酵解或TCA/OxPhos以外的来源。
结论：这些发现强调了糖酵解在支持PMCA神经元功能以维持Ca2+稳态方面的重要作用。此外，他们阐明了细胞质Ca2清除机制对不同能量来源的不同依赖性。
方法：我们的研究涉及评估基础Ca2+水平，并分析选择性结合抑制/阻断关键ATP依赖性机制和抑制TCA/OxPhos或糖酵解ATP来源后诱发神经元Ca2+瞬变的动力学特征。
结果：我们的发现揭示了质膜Ca2ATPase（PMCA）是清除海马锥体神经元中胞质Ca2的主要ATP依赖性机制，在休息和神经元活动期间。值得注意的是,在细胞活动期间，PMCA依赖于糖酵解的ATP，挑战神经元依赖TCA/OxPhos获取ATP的传统观念。锥体神经元中Ca2+清除的其他机制，如SERCA和NCX，似乎依赖于TCA/OxPhos。有趣的是,在休息时,为PMCA和SERCA提供燃料所需的ATP，保持静息Ca2+的两种主要机制，似乎起源于糖酵解或TCA/OxPhos以外的来源。
结论：这些发现强调了糖酵解在支持PMCA神经元功能以维持Ca2+稳态方面的重要作用。此外，他们阐明了细胞质Ca2清除机制对不同能量来源的不同依赖性。
