頁籤選單縮合
題名 | A Further Investigation of ATP-Induced Calcium Mobilization in MDCK Cells |
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作者姓名(外文) | Jan,Chung-ren; Wu,Sheng-nan; Tseng,Ching-jiunn; | 書刊名 | 中國生理學雜誌 |
卷期 | 42:1 1999.03[民88.03] |
頁次 | 頁33-39 |
分類號 | 397 |
關鍵詞 | ATP; MDCK cells; P2 receptors; Fura-2; Calcium signaling; |
語文 | 英文(English) |
英文摘要 | We have previously reported that La�� inhibited the ATP-induced rise in intracellular Ca�� levels ([Ca�ヅ��) measured by fura-2 fluorimetry in Madin Darby canine kidney (MDCK) cells. Here we further investigated the ATP- induced Ca�� signal. ATP caused a rise in [Ca�� ]�寮ose-dependently between 1 μM-1 mM. The rises induced by 10 μM-1 mM ATP were inhibited by Ca�� removal. The pleateau phase of the ATP response was primarily maintained by Ca�� influx because it was reduced or eliminated by Ca�� removal. ATP failed to elevate [Ca�� ]�� after the endoplasmic reticulum Ca�� store had been depleted by 2,5-di-tert-butylhydroquinone or cyclopiazonic acid, suggesting that the ATP-induced Ca�� influx was capacitative Ca�� entry. Capacitative Ca�� entry was directly measured by addition of 5 mM CaCl�� to cells pretreated with ATP (0.1mM) in Ca�� -free medium. This capaci-tative Ca�� entry was inhibited by econazole (25 μM) or SKF96365 (50 μM). The ATP response was significantly enhanced by extracellular alkalization to pH 8 or pretreatment with gly-phe- β -naphthylamide. Pretreatment with carbonylcyanide m- chlorophenylhydrazone (CCCP) or extracellular Na�� removal had no enhancement, implicating that efflux via plasmalemmal Ca�� pumps (but not Na�� /Ca�� exchange) and buffering by lysosomes (but not mitochondria) might be involved in the decay of the ATP response. |
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