Ca2+ responses to ATP via purinoceptors in the early embryonic chick retina
Ca2+ responses to ATP via purinoceptors in the early embryonic chick retina
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DOI：
10.1113/jphysiol.1996.sp021428
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发表时间：
1996-06-15
影响因子：
5.5
通讯作者：
Yamashita, M
中科院分区：
文献类型：
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作者：
Sugioka, M;Fukuda, Y;Yamashita, M
1.用Fura-2荧光法研究了三磷酸腺苷对早期胚胎雏鸡视网膜细胞内钙离子浓度([Ca~(2+)]_i)的影响。在胚胎第3天(E3)从鸡胚胎中分离出整个神经视网膜，测量其荧光强度。加入ATP(大于或等于30 mU M；EC(50)，128 mU M)可使细胞内的钙释放增加，这是因为即使在无钙的条件下，细胞内的钙也会对ATP产生反应。Ca~(2+)对ATP的反应是由P-2U嘌呤受体介导的。P-2U嘌呤受体激动剂尿苷三磷酸(UTP)引起的钙升高(大于或等于3mU M；EC(50)，24 mU M)比ATP、P-2X嘌呤受体激动剂α，β-亚甲基ATP和β-亚甲基ATP，或P-2Y嘌呤受体激动剂2-甲硫基ATP(各500mM)不引起钙反应。苏拉明(100 MU M)和活性蓝2(50 MM)几乎完全阻断了钙离子对500 mU M ATP和200 mU M UTP的响应。从E3到E13，研究了Ca~(2+)对ATP反应的发育规律。Ca~(2+)对ATP的响应在E3时最大，到E8时急剧下降，到E11~13.5时进一步下降。这些结果表明，ATP通过P-2U嘌呤受体动员Ca~(2+)是早期胚胎视网膜细胞的特征。
1. The action of adenosine triphosphate on cytoplasmic Ca2+ concentration ([Ca2+](i)) was studied in the retinal cell of early embryonic chicks with fura-2 fluorescence measurements. The fluorescence was measured from the whole neural retina dissected from chick embryos at embryonic day three (E3).2. Bath application of ATP (greater than or equal to 30 mu M; EC(50), 128 mu M) raised [Ca2+](i) by the release of Ca2+ from intracellular Ca2+ stores, since the Ca2+ response to ATP occurred even in a Ca2+-free medium.3. The Ca2+ response to ATP was mediated by P-2U purinoceptors. An agonist for P-2U purinoceptors, uridine triphosphate (UTP), evoked Ca2+ rises more potently (greater than or equal to 3 mu M; EC(50), 24 mu M) than ATP, agonists for P-2X purinoceptors, alpha,beta-methylene ATP and beta,gamma-methylene ATP, or an agonist for P-2Y purinoceptors, 2-methylthio ATP (500 mu M each), caused no Ca2+ response. Suramin (100 mu M) and Reactive Blue 2 (50 mu M) almost completely blocked the Ca2+ responses to 500 mu M ATP and 200 mu M UTP.4. The developmental profile of the Ca2+ response to ATP was studied from E3 to E13. The Ca2+ response to ATP was largest at E3, drastically declined towards E8 and decreased further until E11-13.5. These results suggest that the Ca2+ mobilization by ATP via P-2U purinoceptors is characteristic of early embryonic retinal cells.