| Author/Editor | Lenasi, Helena; Kohlstedt, Karin; Fichtlscherer, Brigit; Muelsch, Alexander; Busse, Rudi; Fleming, Ingrid | |
| Title | Amlodipine activates the endothelial nitric oxide synthase by altering phosphorylation on Ser(1177) and Thr(495) | |
| Type | članek | |
| Source | Cardiovasc Res | |
| Vol. and No. | Letnik 59, št. 4 | |
| Publication year | 2003 | |
| Volume | str. 844-53 | |
| Language | eng | |
| Abstract | Objective: The Ca(2+) antagonist amlodipine increases the generation of nitric oxide (NO) from native and cultured endothelial cells. The aim of this investigation was to determine whether or not the activation of the endothelial NO synthase (eNOS) by this Ca(2+) antagonist is related to alterations in eNOS phosphorylation. Methods and results: In isolated, pre-contracted, endothelium-intact porcine coronary arteries, amlodipine elicited an NO-mediated relaxation and a leftward shift in the concentration-relaxation curve to bradykinin. Moreover, the Ca(2+) antagonist increased the generation of NO from native endothelial cells, as detected by electron spin resonance spectroscopy and stimulated an 8-fold increase in cyclic GMP levels in cultured endothelial cells. In unstimulated endothelial cells, eNOS was not phosphorylated on Ser(1177) but was phosphorylated on Thr(495). Amlodipine elicited the phosphorylation of Ser(1177) and attenuated Thr(495) phosphorylation, with a time course similar to that of eNOS activation. The amlodipine-induced relaxation of porcine coronary arteries was attenuated by the B(2) kinin receptor antagonist, icatibant, but this antagonist did not affect amlodipine-induced changes in eNOS phosphorylation in cultured endothelial cells. Moreover, amlodipine elicited the NO-mediated relaxation of rat aortic rings which do not express the B(2) receptor. Amlodipine time-dependently attenuated the phosphorylation of protein kinase C (PKC) in endothelial cells, with a time course similar to the changes in eNOS phosphorylation, and prevented the phorbol-12-myristate-13-acetate-induced activation of PKC. The PKC inhibitor, Ro 31-8220, also elicited the phosphorylation of Ser(1177) and the dephosphorylation of Thr(495) in cultured cells and induced a leftward shift in the concentration-relaxation curve to bradykinin in rings of porcine coronary artery. (Abstract truncated at 2000 characters) | |
| Descriptors | ENDOTHELIUM, VASCULAR CORONARY VESSELS AMIODARONE NITRIC-OXIDE SYNTHASE BRADYKININ 5'-GUANYLIC ACID CELLS, CULTURED SIGNAL TRANSDUCTION SWINE ELECTRON SPIN RESONANCE SPECTROSCOPY ANALYSIS OF VARIANCE |