Regulating transient and sustained changes of cytosolic Ca2+ in rat pancreatic acini.
Regulating transient and sustained changes of cytosolic Ca2+ in rat pancreatic acini.
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DOI：
10.1152/ajpcell.1990.258.1.c54
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
T. Hurley;R. Brinck
中科院分区：
文献类型：
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作者：
T. Hurley;R. Brinck
在大鼠胰腺腺泡中加载Fura-2，研究了卡巴胆碱暴露期间胞浆Ca 2+浓度（Cai 2+）变化的调节。当细胞外Ca 2+浓度（Cao 2+）为2.5 mM时，静息Cai 2+为185 +/- 48（SD）nM（n = 23），其上升至696 +/- 222 nM，然后福尔斯在2分钟内下降至401 +/- 106 nM的稳定平台。当Cao 2+小于10 nM时，卡巴胆碱使Cai 2+立即增加3倍，Cai 2+在2-3分钟内消散，Cai 2+稳定地福尔斯降至刺激前水平以下。阿托品阻止对卡巴胆碱的所有反应，当在对卡巴胆碱的反应期间加入阿托品时，Cai 2+在几秒钟内下降到静息值。在卡巴胆碱暴露期间Cai 2+的长期升高需要Ca 2+内流，但Ca 2+内流不受Cai 2+本身增加的调节，也不通过电压门控L型通道进入Ca 2+。毒蕈碱受体操作的Ca 2+进入机制对Ca 2+敏感，因为Ca 2+的持续升高在2.5 mM Ca 2+时最大，但在较低的外部Ca 2+浓度下不太明显。
The regulation of changes in cytosolic Ca2+ concentration (Cai2+) during exposure to carbachol was studied in rat pancreatic acini loaded with fura-2. With an extracellular Ca2+ concentration (Cao2+) of 2.5 mM, resting Cai2+ is 185 +/- 48 (SD) nM (n = 23), which rises to 696 +/- 222 nM, then falls over 2 min to a stable plateau of 401 +/- 106 nM. With Cao2+ less than 10 nM, carbachol produces an immediate threefold increase in Cai2+ that dissipates over 2-3 min, and Cai2+ steadily falls below prestimulation levels. Atropine prevents all responses to carbachol, and when it is added during a response to carbachol, Cai2+ drops to resting values within seconds. Ca2+ influx is required for the prolonged elevation of Cai2+ during carbachol exposure, but Ca2+ entry is not regulated by an increase in Cai2+ itself nor does Ca2+ enter via voltage-gated L-type channels. The muscarinic receptor-operated Ca2+ entry mechanism is sensitive to Cao2+, since sustained elevations in Cai2+ are maximal at 2.5 mM Cao2+ but are much less pronounced at lower external Ca2+ concentrations.