Guffey Samuel C, Fliegel Larry, Goss Greg G
Department of Biological Sciences, Z512 Biological Sciences Bldg, University of Alberta, Edmonton, AB T6G 2E9, Canada; Bamfield Marine Sciences Centre, 100 Pachena Road, Bamfield, BC V0R 1B0, Canada.
Department of Biochemistry, 347 Medical Sciences Bldg, University of Alberta, Edmonton, AB T6G 2H7, Canada.
Comp Biochem Physiol B Biochem Mol Biol. 2015 Oct;188:46-53. doi: 10.1016/j.cbpb.2015.06.003. Epub 2015 Jun 23.
Na(+)/H(+) Exchanger (NHE) proteins mediate cellular and systemic homeostasis of sodium and acid and may be the major sodium uptake method for fishes. We cloned and sequenced NHE2 and NHE3 from the gill of the North Pacific Spiny Dogfish shark Squalus suckleyi and expressed them in functional form in NHE-deficient (AP-1) cell lines. Estimated IC50 for inhibition of NHE activity by amiloride and EIPA were 55 μmol l(-1) and 4.8 μmol l(-1), respectively, for NHE2 and 9 μmol l(-1) and 24 μmol l(-1), respectively, for NHE3. Phenamil at 100 μmol l(-1) caused less than 16% inhibition of activity for each isoform. Although the IC50 are similar for the two isoforms, dfNHE2 is less sensitive than human NHE2 to inhibition by amiloride and EIPA, while dfNHE3 is more sensitive than human NHE3. These IC50 estimates should be considered when selecting inhibitor doses for fishes and for reinterpretation of previous studies that use these pharmacological agents.
钠/氢交换体（NHE）蛋白介导细胞和全身的钠及酸稳态，可能是鱼类主要的钠摄取方式。我们从北太平洋棘鲨（Squalus suckleyi）的鳃中克隆并测序了NHE2和NHE3，并在缺乏NHE的（AP-1）细胞系中以功能形式表达它们。氨氯吡咪和EIPA抑制NHE活性的估计IC50，对于NHE2分别为55 μmol l(-1)和4.8 μmol l(-1)，对于NHE3分别为9 μmol l(-1)和24 μmol l(-1)。100 μmol l(-1)的非那明对每种异构体活性的抑制小于16%。虽然两种异构体的IC50相似，但dfNHE2比人NHE2对氨氯吡咪和EIPA的抑制更不敏感，而dfNHE3比人NHE3更敏感。在为鱼类选择抑制剂剂量以及重新解释以前使用这些药物的研究时，应考虑这些IC50估计值。
