Muscarinic and purinergic Ca2+ mobilizations in the neural retina of early embryonic chick
Muscarinic and purinergic Ca2+ mobilizations in the neural retina of early embryonic chick
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DOI：
10.1016/s0736-5748(96)00074-3
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发表时间：
1996-10-01
影响因子：
1.8
通讯作者：
Yamashita, M
中科院分区：
文献类型：
--
作者：
Sakaki, Y;Fukuda, Y;Yamashita, M
乙酰胆碱和三磷酸腺苷(ATP)通过M受体和P-2U嘌呤受体从胚胎早期鸡神经视网膜的细胞内钙库释放钙离子，从而提高细胞内钙离子浓度。用Fura-2荧光检测技术研究了毒鼠碱和嘌呤能钙离子反应的信号转导机制。抑制磷脂酰肌醇代谢的Li+(1 MM)可促进Ca~(2+)升高至M受体激动剂氨基甲胆碱(CCH，30 mU/M)和ATP(200 mU/L)。三磷酸肌醇(IP3)敏感的钙库钙通道的钙-ATPase抑制剂塔普西林(250 NM)可阻断钙升至CCH(100 MU M)和ATP(500 MU M)。磷脂酶Cβ的抑制剂U-73122(2mU M)可抑制Ca~(2+)向ATP的升高(500mM)，但其类似物U-73343(2mM)对此无抑制作用。与之相反，U-73122和U-73343均能抑制Ca~(2+)升高至CCH(100mM)。百日咳毒素(250 ng/ml)可部分抑制三磷酸腺苷诱导的细胞内钙升高，但对CCH诱导的细胞内钙升高无抑制作用。毒碱能和嘌呤能钙离子动员之间存在串扰，但它们不是闭塞的。这项研究表明，毒鼠碱和嘌呤能钙离子的动员利用了IP3敏感的钙库，但毒碱和嘌呤能钙离子反应之间涉及不同的信号转导途径。版权所有(C)1996 ISDN
Acetylcholine and adenosine triphosphate (ATP) raise intracellular Ca2+ concentration via muscarinic receptors and P-2U purinoceptors by releasing Ca2+ from intracellular Ca2+ stores in the neural retina of early embryonic chick. The signal transduction mechanisms for the muscarinic and purinergic Ca2+ responses were studied with fura-2 fluorescence measurements. Li+ (1 mM), which inhibits phosphatidylinositol metabolism, enhanced both the Ca2+ rises to carbamylcholine (CCh, 30 mu M), a muscarinic agonist, and ATP (200 mu M). Thapsigargin (250 nM), an inhibitor of Ca2+-ATPase of inositol trisphosphate (IP3)-sensitive Ca2+ stores, abolished both the Ca2+ rises to CCh (100 mu M) and ATP (500 mu M). U-73122 (2 mu M), an inhibitor of phospholipase C beta, suppressed the Ca2+ rise to ATP (500 mu M), but its analog U-73343 (2 mu M) did not suppress it. In contrast, both U-73122 and U-73343 suppressed the Ca2+ rise to CCh (100 mu M). Pertussis toxin (250 ng/ml) suppressed the ATP-induced Ca2+ rise at least partly, whereas no inhibition was observed on the CCh-induced Ca2+ rise. Cross-talk occurred between the muscarinic and purinergic Ca2+ mobilizations but they were not occlusive. This study suggests that the muscarinic and purinergic Ca2+ mobilizations utilize IP3-sensitive Ca2+ stores, but different signal transduction pathways are involved in between the muscarinic and purinergic Ca2+ responses. Copyright (C) 1996 ISDN