Gruwel M L, Culić O, Muhs A, Williams J P, Schrader J
National Research Council, Institute for Biodiagnostics, Winnipeg, Manitoba, Canada.
Biochem Biophys Res Commun. 1998 Jan 6;242(1):93-7. doi: 10.1006/bbrc.1997.7908.
Using an in vitro cell system and Cs+ NMR techniques we were able to show that porcine aortic endothelial cells (PAEC) reduce their Na(+)-K(+)-ATPase activity upon an increase in intracellular cAMP. Reduction in the pump rate was due to phosphorylation of the alpha-subunit of the ATPase as shown by immunoprecipitation. Apart from a pump inhibiton using 8-Br-cAMP and IBMX, we were also able to show that changes in the Na(+)-K(+)-ATPase activity could be mediated by the adenosine-A2 and prostaglandin receptor agonists 5'-N-Ethylcarboxamidoadenosine and Iloprost, respectively. Parallel to a decrease in pump activity we also observed a decrease in intracellular Cs+, indicating opening of K+ channels.
利用体外细胞系统和铯离子核磁共振技术，我们能够证明，猪主动脉内皮细胞（PAEC）在细胞内环磷酸腺苷（cAMP）增加时会降低其钠钾ATP酶活性。如免疫沉淀所示，泵速率的降低是由于ATP酶α亚基的磷酸化。除了使用8-溴环磷酸腺苷（8-Br-cAMP）和异丁基甲基黄嘌呤（IBMX）抑制泵功能外，我们还能够证明，钠钾ATP酶活性的变化可能分别由腺苷A2和前列腺素受体激动剂5'-N-乙基羧酰胺腺苷和伊洛前列素介导。与泵活性降低同时，我们还观察到细胞内铯离子减少，表明钾离子通道开放。
