Civan M M, Degani H, Margalit Y, Shporer M
Am J Physiol. 1983 Sep;245(3):C213-9. doi: 10.1152/ajpcell.1983.245.3.C213.
The shift reagent dysprosium tripolyphosphate [Dy(PPPi)7-2] has been applied to the nuclear magnetic resonance (NMR) study of 23Na in frog skin. The anion complex produces slight increases in the transcellular short-circuit current and conductance of the tissue. However, the electrophysiological responsiveness of the tissue to vasopressin, amiloride, and transient removal of extracellular potassium appear unimpaired. A large signal of [31P]phosphocreatine was also observed, further documenting that relatively little damage was produced by the reagent. Three signals of 23Na were observed, reflecting the sodium pools in an external standard solution, the extracellular space, and a medium relatively inaccessible to Dy(PPPi)7-2. The size of the reagent-insensitive signal could be increased by ouabain, a selective inhibitor of sodium extrusion, and could be decreased by amiloride, a selective inhibitor of sodium entry. The results indicate that the anion complex-insensitive signal reflects, at least in part, intracellular sodium and suggest that 23Na may become a useful complementary tool for monitoring the intracellular sodium content of transporting epithelia.
位移试剂三聚磷酸镝[Dy(PPPi)7-2]已应用于蛙皮中23Na的核磁共振（NMR）研究。该阴离子络合物使组织的跨细胞短路电流和电导略有增加。然而，组织对血管加压素、氨氯吡脒以及细胞外钾离子短暂去除的电生理反应性似乎未受损害。还观察到了[31P]磷酸肌酸的一个大信号，进一步证明该试剂造成的损伤相对较小。观察到了23Na的三个信号，分别反映了外标溶液、细胞外空间以及Dy(PPPi)7-2相对难以进入的介质中的钠池。钠泵选择性抑制剂哇巴因可增加对该试剂不敏感信号的大小，而钠内流选择性抑制剂氨氯吡脒可减小其大小。结果表明，对阴离子络合物不敏感的信号至少部分反映了细胞内钠，提示23Na可能成为监测转运上皮细胞内钠含量的一种有用的补充工具。
