Irina V. Kovyazina, Kamilla A. Mukhutdinova, Alexey M. Petrov
{"title":"小鼠神经肌肉连接处24-羟基胆固醇介导的神经递质释放调节的频率依赖机制：活性氧的作用。","authors":"Irina V. Kovyazina, Kamilla A. Mukhutdinova, Alexey M. Petrov","doi":"10.1007/s11064-025-04563-z","DOIUrl":null,"url":null,"abstract":"<div><p>Neuron-specific enzyme CYP46A1 converts cholesterol to 24-hydroxycholesterol (24-HC), which crosses the brain blood barrier, entering the systemic circulation. Production of 24-HC depends on synaptic and metabolic activity and changes significantly during aging and neurodegenerative diseases. Previously, it was shown that prolonged application of 24-HC (0.4 µM) suppressed recruitment of synaptic vesicles to exocytosis during 20 Hz nerve stimulation acting <i>via</i> elevation of NO synthesis at the mouse neuromuscular junctions (NMJs). Here, using microelectrode recording of postsynaptic responses and fluorescent trackers for endo-exocytosis, NO and reactive oxygen species (ROS) production, the effect of 24-HC on neuromuscular transmission at 10 Hz and 70 Hz nerve firing was studied. At 10 Hz stimulation, 24-HC decreased neurotransmitter release and synaptic vesicle involvement in exocytosis. This was associated with elevation of NO synthesis without marked changes in ROS generation. However, at 70 Hz activity, 24-HC increased the recruitment of synaptic vesicles in exocytosis in combination with attenuation of NO synthesis and enhancement of ROS production. 24-HC-mediated increase in ROS production was suppressed by NADPH-oxidase inhibitor VAS2870, and antioxidant N-acetylcysteine completely prevented 24-HC-dependent potentiation of neurotransmission and suppression of NO synthesis during 70 Hz activity. Similarly, protein kinase C inhibitor chelerythrine blocked 24-HC-mediated enhancement of exocytosis and attenuation of NO generation at 70 Hz stimulation. Thus, 24-HC suppresses neurotransmission at moderate-frequency activity, probably <i>via</i> elevation of NO synthesis, but it potentiates neurotransmitter release and synaptic vesicle recruitment into exocytosis during high-frequency nerve firing via an NADPH oxidase/ROS/protein kinase C pathway.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":719,"journal":{"name":"Neurochemical Research","volume":"50 5","pages":""},"PeriodicalIF":3.8000,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Frequency-Dependent Mechanism of 24-Hydroxycholesterol-Mediated Modulation of Neurotransmitter Release at the Mouse Neuromuscular Junction: The Role of Reactive Oxygen Species\",\"authors\":\"Irina V. Kovyazina, Kamilla A. Mukhutdinova, Alexey M. Petrov\",\"doi\":\"10.1007/s11064-025-04563-z\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Neuron-specific enzyme CYP46A1 converts cholesterol to 24-hydroxycholesterol (24-HC), which crosses the brain blood barrier, entering the systemic circulation. Production of 24-HC depends on synaptic and metabolic activity and changes significantly during aging and neurodegenerative diseases. Previously, it was shown that prolonged application of 24-HC (0.4 µM) suppressed recruitment of synaptic vesicles to exocytosis during 20 Hz nerve stimulation acting <i>via</i> elevation of NO synthesis at the mouse neuromuscular junctions (NMJs). Here, using microelectrode recording of postsynaptic responses and fluorescent trackers for endo-exocytosis, NO and reactive oxygen species (ROS) production, the effect of 24-HC on neuromuscular transmission at 10 Hz and 70 Hz nerve firing was studied. At 10 Hz stimulation, 24-HC decreased neurotransmitter release and synaptic vesicle involvement in exocytosis. This was associated with elevation of NO synthesis without marked changes in ROS generation. However, at 70 Hz activity, 24-HC increased the recruitment of synaptic vesicles in exocytosis in combination with attenuation of NO synthesis and enhancement of ROS production. 24-HC-mediated increase in ROS production was suppressed by NADPH-oxidase inhibitor VAS2870, and antioxidant N-acetylcysteine completely prevented 24-HC-dependent potentiation of neurotransmission and suppression of NO synthesis during 70 Hz activity. Similarly, protein kinase C inhibitor chelerythrine blocked 24-HC-mediated enhancement of exocytosis and attenuation of NO generation at 70 Hz stimulation. Thus, 24-HC suppresses neurotransmission at moderate-frequency activity, probably <i>via</i> elevation of NO synthesis, but it potentiates neurotransmitter release and synaptic vesicle recruitment into exocytosis during high-frequency nerve firing via an NADPH oxidase/ROS/protein kinase C pathway.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>\",\"PeriodicalId\":719,\"journal\":{\"name\":\"Neurochemical Research\",\"volume\":\"50 5\",\"pages\":\"\"},\"PeriodicalIF\":3.8000,\"publicationDate\":\"2025-09-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Neurochemical Research\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s11064-025-04563-z\",\"RegionNum\":3,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"BIOCHEMISTRY & MOLECULAR BIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Neurochemical Research","FirstCategoryId":"3","ListUrlMain":"https://link.springer.com/article/10.1007/s11064-025-04563-z","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
Frequency-Dependent Mechanism of 24-Hydroxycholesterol-Mediated Modulation of Neurotransmitter Release at the Mouse Neuromuscular Junction: The Role of Reactive Oxygen Species
Neuron-specific enzyme CYP46A1 converts cholesterol to 24-hydroxycholesterol (24-HC), which crosses the brain blood barrier, entering the systemic circulation. Production of 24-HC depends on synaptic and metabolic activity and changes significantly during aging and neurodegenerative diseases. Previously, it was shown that prolonged application of 24-HC (0.4 µM) suppressed recruitment of synaptic vesicles to exocytosis during 20 Hz nerve stimulation acting via elevation of NO synthesis at the mouse neuromuscular junctions (NMJs). Here, using microelectrode recording of postsynaptic responses and fluorescent trackers for endo-exocytosis, NO and reactive oxygen species (ROS) production, the effect of 24-HC on neuromuscular transmission at 10 Hz and 70 Hz nerve firing was studied. At 10 Hz stimulation, 24-HC decreased neurotransmitter release and synaptic vesicle involvement in exocytosis. This was associated with elevation of NO synthesis without marked changes in ROS generation. However, at 70 Hz activity, 24-HC increased the recruitment of synaptic vesicles in exocytosis in combination with attenuation of NO synthesis and enhancement of ROS production. 24-HC-mediated increase in ROS production was suppressed by NADPH-oxidase inhibitor VAS2870, and antioxidant N-acetylcysteine completely prevented 24-HC-dependent potentiation of neurotransmission and suppression of NO synthesis during 70 Hz activity. Similarly, protein kinase C inhibitor chelerythrine blocked 24-HC-mediated enhancement of exocytosis and attenuation of NO generation at 70 Hz stimulation. Thus, 24-HC suppresses neurotransmission at moderate-frequency activity, probably via elevation of NO synthesis, but it potentiates neurotransmitter release and synaptic vesicle recruitment into exocytosis during high-frequency nerve firing via an NADPH oxidase/ROS/protein kinase C pathway.
期刊介绍：
Neurochemical Research is devoted to the rapid publication of studies that use neurochemical methodology in research on nervous system structure and function. The journal publishes original reports of experimental and clinical research results, perceptive reviews of significant problem areas in the neurosciences, brief comments of a methodological or interpretive nature, and research summaries conducted by leading scientists whose works are not readily available in English.
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