Role of membrane potential in endothelium-dependent relaxation of isolated mouse main pulmonary artery

Article Article scientifique Article Role of membrane potential in endothelium-dependent relaxation of isolated mouse main pulmonary artery eng 2006 author Tolsa Jean-Françoise author Marino Mathieu 591138 author Peyter Anne-Christine author Beny Jean-Louis 26368 501-507 10.1097/01.fjc.0000211742.86078.8b 0160-2446 The physiology of smooth muscle and endothelial cells of a particular vascular bed and from different species differs from each other. Acetylcholine causes an endothelium-dependent relaxation of preconstricted pulmonary arteries from the rat. This relaxation is mediated by nitric oxide (NO) plus a yet-unidentified endothelium-derived hyperpolarizing factor, which relaxes the smooth muscles by hyperpolarizing factor, which relaxes the smooth muscles by hyperpolarizing them. Our aim is to test whether these observations could be generalized to the smooth muscle cells from the mouse pulmonary artery. Smooth muscle or endothelial cell membrane potential of strips of murine pulmonary artery were measured simultaneously with the force developed by the strip. Acetylcholine hyperpolarized the endothelial cells. However, acetylcholine did not induce an endothelium-dependent hyperpolarization of the smooth muscle, while it relaxed the strip in an endothelium-dependent manner. This relaxation was abolished by an inhibitor of NO synthesis, nitro-<sub>L</sub>-arginine. Moreover, nitroglycerin relaxed the strips without changing the membrane potential of the smooth muscle cells. Injection of Lucifer yellow into the endothelial cells and the smooth muscle cells did not show heterocellular dye coupling. Furthermore, electron microscopy did not show gap junction plate at the myoendothelial junctions. We conclude that in the mouse main pulmonary artery, NO alone is responsible for the acetylcholine-induced endothelium-dependent vasodilatation, whereas the phenomenon called endothelium-derived hyperpolizing factor is not present. Therefore, caution should be taken when comparing different animal models to study pulmonary circulation and its reactivity. Acetylcholine EDHF Membrane potential Mouse NO Pulmonary artery Dewey 590 44 Département de génétique et évolution 162 false Journal of cardiovascular pharmacology 47 4 048d1116-e772-41ce-b8a8-ff333c741b47 Article (Published version) Restricted TOLSA_JCP_5072006.pdf 252481 application/pdf restrictedAccess Faculté des sciences / Section de biologie / Département de génétique et évolution

Title	Published in	Access level	OA Policy	Year	Views	Downloads

Role of membrane potential in endothelium-dependent relaxation of isolated mouse main pulmonary artery	Journal of cardiovascular pharmacology			2006	182	0

Archive ouverte UNIGE

Marino, Mathieu