Stauderman K A, Murawsky M M
Marion Merrell Dow Research Institute, Cincinnati, Ohio 45215.
J Biol Chem. 1991 Oct 15;266(29):19150-3.
The role of a Ca(2+)-induced Ca2+ release (CICR) mechanism in the generation of agonist-induced increases of intracellular free Ca2+ concentration ([Ca2+]i) was studied in bovine adrenal chromaffin cells. In single cells, repetitive stimulations with caffeine at 200-s intervals evoked reproducible spikes of [Ca2+]i. Ryanodine, an agent that interacts with the CICR channel of muscle, inhibited the caffeine-induced spikes of [Ca2+]i in a "use-dependent" way. High affinity binding sites for [3H]ryanodine (Kd 3.3 nM, Bmax 26 fmol/mg protein) were also detected in membranes from chromaffin cells, supporting the presence of a caffeine- and ryanodine-sensitive CICR channel. Pretreatment of single cells with caffeine + ryanodine to reduce the size of the caffeine-sensitive Ca2+ compartment inhibited a subsequent spike of [Ca2+]i evoked by histamine, a D-myo-inositol 1,4,5-trisphosphate-forming agonist. This demonstrates that a significant portion of the Ca2+ released by histamine comes from a caffeine- and ryanodine-sensitive pool. Ryanodine inhibited by 50% the size of [Ca2+]i spikes evoked by repetitive stimulation with histamine and did so in a use-dependent manner. These data suggest that, in addition to D-myoinositol 1,4,5-trisphosphate, activation of a caffeine- and ryanodine-sensitive CICR channel participates in the generation of histamine-induced release of intracellular Ca2+.
在牛肾上腺嗜铬细胞中研究了钙诱导钙释放（CICR）机制在激动剂诱导的细胞内游离钙浓度（[Ca2+]i）升高过程中的作用。在单细胞中，以200秒的间隔用咖啡因进行重复刺激可诱发[Ca2+]i的可重复峰值。ryanodine是一种与肌肉的CICR通道相互作用的药物，它以“使用依赖性”方式抑制咖啡因诱导的[Ca2+]i峰值。在嗜铬细胞膜中也检测到了[3H]ryanodine的高亲和力结合位点（Kd 3.3 nM，Bmax 26 fmol/mg蛋白），这支持了存在对咖啡因和ryanodine敏感的CICR通道。用咖啡因+ryanodine预处理单细胞以减小对咖啡因敏感的钙池大小，可抑制随后由组胺（一种形成D-肌醇1,4,5-三磷酸的激动剂）诱发的[Ca2+]i峰值。这表明组胺释放的大部分Ca2+来自对咖啡因和ryanodine敏感的池。Ryanodine使组胺重复刺激诱发的[Ca2+]i峰值大小降低50%，且以使用依赖性方式进行。这些数据表明，除了D-肌醇1,4,5-三磷酸外，对咖啡因和ryanodine敏感的CICR通道的激活也参与了组胺诱导的细胞内Ca2+释放的产生。
