| Effect of Calcium on Spontaneous Quantal Transmitter Secretion from ACh-Loaded Myocytes |
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| 作者姓名： | 亓磊 李如心 何湘萍 谢佐平 |
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| 作者单位： | Laboratory of Neurobiology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China，Laboratory of Neurobiology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China，Laboratory of Neurobiology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China，Laboratory of Neurobiology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China |
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| 基金项目： | Supported by the National Natural Science Foundation of China (No. 30370468) |
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| 摘 要： | Introduction Transmitter secretion requires specialized secretory or- ganelles, the synaptic vesicles, for the packaging, stor- age, and exocytotic release of the transmitters1,2]. The neurotransmitter acetylcholine (ACh) is released at the neuromuscular…
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| 关 键 词： | 妊娠试验 有爪蟾蜍 肌细胞 乙酰胆碱 细胞外钙离子 |
| 收稿时间： | 2005-09-21 |
| 修稿时间： | 2005-09-212005-12-27 |
Effect of Calcium on Spontaneous Quantal Transmitter Secretion from ACh-Loaded Myocytes |
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| QI Lei,LI Ruxin,HE Xiangping,XIE Zuoping.Effect of Calcium on Spontaneous Quantal Transmitter Secretion from ACh-Loaded Myocytes[J].Tsinghua Science and Technology,2006,11(4):433-439. |
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| Authors: | QI Lei LI Ruxin HE Xiangping XIE Zuoping |
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| Institution: | Laboratory of Neurobiology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China;From the Division of Hematology and Oncology, Wayne State University School of Medicine, Detroit, Michigan;From the Institute for Animal Experimentation, Hokkaido University School of Medicine, Sapporo and the Department of Epizootiology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan;From the Department of Surgery, Division of Urology, Duke University Medical Center, Durham, North Carolina;Laboratory of Cell Biology, National Institute of Mental Health, Building 36, Room 3A17, Bethesda, MD 208920-4092, USA;Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China |
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| Abstract: | Spontaneous secretions occur in both neurons and non-neuronal cells, and calcium is important for these secretion processes. However, the detailed roles of calcium on the secretions have not yet been identified. In the present study, cultured Xenopus myocytes loaded with exogenous acetylcholine (ACh) into the cytoplasm in the absence of extracellular Ca2 undergo spontaneous quantal ACh secretion as detected by the appearance of pulsatile miniature endplate currents. Analysis of the frequencies, amplitudes, and time courses of these currents suggests that similar cellular mechanisms are involved in the secretions of ACh in normal medium and Ca2 -free solution. Various doses of ryanodine were used to regulate the intra- cellular Ca2 to different levels. The spontaneous ACh secretion from myocytes in Ca2 -free medium was decreased by reducing intracellular Ca2 levels and enhanced by increasing cytosolic Ca2 levels. These observations demonstrate that the spontaneous secretion from isolated myocytes and the effect of ryano- dine on ACh-loaded cells are both independent of extracellular Ca2 while Ca2 in the sarcoplasmic reticu- lum plays a crucial role in the secretions. |
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| Keywords: | spontaneous secretion Xenopus myocytes acetylcholine (ACh) extracellular Ca2 ryanodine intracellular Ca2 |
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