Regulation of endothelial Na(+)-K(+)-ATPase activity by cAMP.
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.
Gruwel
M L
ML
National Research Council, Institute for Biodiagnostics, Winnipeg, Manitoba, Canada. gruwel@zeno.ibd.nrc.ca
Culić
O
O
Muhs
A
A
Williams
J P
JP
Schrader
J
J
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology; D001692:Biological Transport / Q000187:drug effects; D002586:Cesium / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000201:enzymology*; D016285:Iloprost / Q000494:pharmacology; D019906:Nuclear Magnetic Resonance, Biomolecular; D011188:Potassium / Q000378:metabolism; D058906:Purinergic P1 Receptor Agonists; D011982:Receptors, Prostaglandin / Q000819:agonists; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects*; D013552:Swine
D058906:Purinergic P1 Receptor Agonists; D011982:Receptors, Prostaglandin; D002586:Cesium; D015124:8-Bromo Cyclic Adenosine Monophosphate; D019830:Adenosine-5'-(N-ethylcarboxamide); D000242:Cyclic AMP; D000254:Sodium-Potassium-Exchanging ATPase; D016285:Iloprost; D011188:Potassium; D015056:1-Methyl-3-isobutylxanthine