8-BrcAMP does not affect Na-K-2Cl cotransport in winter flounder intestine.
8-BrcAMP does not affect Na-K-2Cl cotransport in winter flounder intestine.
复制标题
8-BrcAMP 不影响冬鲽鱼肠道中的 Na-K-2Cl 共转运。
DOI：
10.1152/ajpcell.1988.255.2.c246
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Nash,NT
中科院分区：
文献类型：
--
作者：
Rao,MC;Nash,NT
比目鱼肠上皮细胞具有腔Na-K-2Cl共转运和钾分泌机制，占短路电流（Isc）通过组织。这种上皮也具有高度的阳离子选择性。布美他尼或8-溴鸟苷3 '，5'-环一磷酸（8-BrcGMP）完全抑制Isc、Na-K-2Cl共转运和K分泌，而8-溴腺苷3 '，5'-环一磷酸（8-BrcAMP）抑制K分泌，部分抑制Isc，并大大增加Cl渗透性。虽然已经研究了腺苷3 '，5'-环磷酸（cAMP）对其他Na-K-2Cl共转运系统的直接影响，但8-BrcAMP对比目鱼肠Na-K-2Cl共转运的影响尚未直接测量。在这项研究中，8-BrcAMP和布美他尼，无论是单独或组合，对流入（初始摄取率）的Cl，Rb和Na跨腔表面的比目鱼肠的影响进行了检查。布美他尼显著抑制Na（50%）、Cl和Rb内流（各70%）。与此相反，8-BrcAMP显着增加氯离子内流在布美他尼的存在或不存在，从而不影响布美他尼敏感的氯离子内流。核苷酸既不改变布美他尼敏感的Rb内流，也不改变在短路条件下测量的净透皮Na吸收，但导致Isc降低51-60%。布美他尼敏感性钠内流的测量显示出较大的实验变异性，但8-BrcAMP的影响无统计学意义。前列腺素E1（PGE 1，10 μ M）和毛喉素（10 μ M），但不是心房利钠因子（1 μ M）增加比目鱼肠[cAMP]分别为200和237%，并像8-BrcAMP，增加组织电导。（250字处删节）
The flounder intestinal epithelium possesses luminal Na-K-2Cl cotransport and K secretory mechanisms that account for the short-circuit current (Isc) across the tissue. This epithelium is also highly cation selective. Bumetanide or 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP) completely inhibit Isc, Na-K-2Cl cotransport, and K secretion, whereas 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) inhibits K secretion, partially inhibits Isc, and greatly increases Cl permeability. Although the direct effects of adenosine 3',5'-cyclic monophosphate (cAMP) on other Na-K-2Cl cotransport systems have been examined, the effects of 8-BrcAMP on flounder intestinal Na-K-2Cl cotransport have not been directly measured. In this study, the effects of 8-BrcAMP and bumetanide, either alone or in combination, on the influx (initial rates of uptake) of Cl, Rb, and Na across the luminal surface of the flounder intestine were examined. Bumetanide significantly inhibited Na (50%), Cl, and Rb influx (70% each). In contrast, 8-BrcAMP significantly increased Cl influx in the presence or absence of bumetanide and thereby did not effect the bumetanide-sensitive Cl influx. The nucleotide neither altered bumetanide-sensitive Rb influx nor net transpithelial Na absorption measured under short-circuit conditions but caused a 51-60% decrease in Isc. Measurements of bumetanide-sensitive Na influx exhibited large experimental variability but showed no statistically significant effects of 8-BrcAMP. Prostaglandin E1 (PGE1, 10 microM) and forskolin (10 microM) but not atrial natriuretic factor (1 microM) increased flounder intestinal [cAMP] 200 and 237%, respectively, and, like 8-BrcAMP, increased tissue conductance.(ABSTRACT TRUNCATED AT 250 WORDS)