Sodium-potassium pump and sodium-calcium exchange in adult and neonatal canine cardiac sarcolemma.
Sodium-potassium pump and sodium-calcium exchange in adult and neonatal canine cardiac sarcolemma.
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成人和新生儿犬心脏肌膜中的钠钾泵和钠钙交换。
DOI：
10.1152/ajpheart.1993.264.2.h320
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Michael,LH
中科院分区：
文献类型：
--
作者：
Hanson,GL;Schilling,WP;Michael,LH
本研究的目的是确定Na（+）-K+泵和Na（+）-Ca 2+交换器这两个被认为在心脏兴奋-收缩偶联中重要的系统在出生后发育期间是否发生变化。在成年和新生犬心肌细胞膜制备物中，发现成年犬的Na（+）-K（+）-腺苷三磷酸酶（ATP酶）活性和特异性[3 H]哇巴因结合高于新生犬，尽管Na（+）-K（+）-ATP酶周转数没有显著差异。此外，哇巴因协会和解离速率常数，在各种条件下检查，是相同的新生儿和成人的准备。这些结果表明，每毫克肌膜蛋白的泵单位的数量在出生后的发展变化。相反，Na（+）依赖性-45 Ca 2+内流的初始速率（Na（+）-Ca 2+交换活性的指标）在两个年龄组中没有显著差异。此外，交换器对囊外Ca 2+和K+的敏感性是相同的。总之，在出生后发育过程中，肌膜Na（+）-K（+）-ATP酶和[3 H]哇巴因结合从新生儿到成人增加，而Na（+）-Ca 2+交换活性保持不变。这可能导致新生儿Na（+）-Ca 2+交换系统中Ca 2+通量比成人更重要。
The purpose of this study was to determine whether the Na(+)-K+ pump and the Na(+)-Ca2+ exchanger, two systems thought to be important in excitation-contraction coupling in the heart, change during postnatal development. In adult and neonatal canine cardiac sarcolemmal preparations, Na(+)-K(+)-adenosine-triphosphatase (ATPase) activity and specific [3H]ouabain binding were found to be higher in the adult compared with the neonate, although Na(+)-K(+)-ATPase turnover numbers were not significantly different. Furthermore, ouabain association and dissociation rate constants, examined under a variety of conditions, were the same for both the neonate and adult preparations. These results suggest that the number of pump units per milligram sarcolemmal protein changes during postnatal development. In contrast, the initial rate of Na(+)-dependent-45Ca2+ influx, an index of Na(+)-Ca2+ exchange activity, was not significantly different in the two age groups. Additionally, the sensitivity of the exchanger to extravesicular Ca2+ and K+ was the same. In summary, during postnatal development sarcolemmal Na(+)-K(+)-ATPase and [3H]ouabain binding increase from neonate to adult, whereas Na(+)-Ca2+ exchange activity remains the same. This may result in a greater importance of Ca2+ flux through the Na(+)-Ca2+ exchange system in the neonate compared with the adult.