Isoform-specific regulation of the sodium pump by alpha- and beta-adrenergic agonists in the guinea-pig ventricle.
Isoform-specific regulation of the sodium pump by alpha- and beta-adrenergic agonists in the guinea-pig ventricle.
复制标题
豚鼠心室中α-和β-肾上腺素能激动剂对钠泵的亚型特异性调节。
DOI：
10.1111/j.1469-7793.1999.0377v.x
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Baldo,GJ
中科院分区：
文献类型：
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作者：
Gao,J;Wymore,R;Wymore,RT;Wang,Y;McKinnon,D;Dixon,JE;Mathias,RT;Cohen,IS;Baldo,GJ
在RNA酶保护试验中使用豚鼠心室以确定存在哪种Na+-K+泵的α亚型，并且在全细胞膜片钳研究中使用心室肌细胞以研究α和β肾上腺素能激动剂对Na+-K+泵电流的作用。RNA酶保护试验表明，豚鼠心室肌中存在Na ~+-K ~+-ATP酶α亚基的两种亚型。α1-亚型的mRNA占总泵信息的82%，其余为α2-亚型。我们先前已经证明β-肾上腺素能激动剂通过蛋白激酶A（PKA）依赖性途径影响Na+-K+泵电流（Ip）。我们现在表明，这些β效应是针对α1亚型的Na+-K+泵。我们以前也表明，α-肾上腺素能激动剂通过蛋白激酶C（PKC）依赖性途径增加IP。我们现在表明，这些α-亚型的影响是针对α2亚型的Na+-K+泵。这些结果表明，肾上腺素能激活对心脏Na+-K+泵活性的影响可能具有区域特异性，这取决于Na+-K+泵的α-亚型表达。
Guinea-pig ventricle was used in the RNase protection assays to determine which α-isoforms of the Na+-K+ pumps are present, and ventricular myocytes were used in whole cell patch clamp studies to investigate the actions of α- and β-adrenergic agonists on Na+-K+ pump current. RNase protection assays showed that two isoforms of the α-subunit of the Na+-K+-ATPase are present in guinea-pig ventricle. The mRNA for the α1-isoform comprises 82 % of the total pump message, the rest being the α2-isoform. We have previously shown that β-adrenergic agonists affect Na+-K+ pump current (Ip) through a protein kinase A (PKA)-dependent pathway. We now show that these β-effects are targeted to the α1-isoform of the Na+-K+ pumps. We have also previously shown that α-adrenergic agonists increase Ip through a protein kinase C (PKC)-dependent pathway. We now show that these α-isoform effects are targeted to the α2-isoform of the Na+-K+ pumps. These results suggest the effects of adrenergic activation on Na+-K+ pump activity in the heart can be regionally specific, depending on which α-isoform of the Na+-K+ pump is expressed.