科研之友
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摘要
Monosialotetrahexosylganglioside (GM1) is a glycosphingolipid present in most cell membranes that displays antioxidant and neuroprotective properties. It has been recently described that GM1 induces pial vessel vasodilation and increases NO (x) content in cerebral cortex, which are fully prevented by the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME). However, it is not known whether GM1 relaxes larger vessels, as well as the mechanisms by which GM1 causes vasorelaxation. In this study, we demonstrate that GM1 (10, 30, 100, 300 A mu M, 1 and 3 mM) induces vascular relaxation determined by isometric tension studies in rat mesenteric artery rings contracted with 1 A mu M phenylephrine. The vasorelaxation induced by GM1 was abolished by endothelium removal, by incubation with l-NAME (1 A mu M), and partially inhibited by the blockade of potassium channels by 1 mM tetraethylammonium, 10 A mu M glibenclamide, by the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (10 A mu M), and by 50 nM charybdotoxin, a blocker of large and intermediate conductance calcium-activated potassium channels. Moreover, GM1-induced relaxation was not affected by apamin (50 nM), a small conductance calcium-activated potassium channel blocker. The results indicate that direct and indirect nitric oxide pathways play a pivotal role in vasorelaxation induced by GM1, which is mediated mainly by potassium channels activation. We suggest that vasodilation may underlie some of the biological effects of exogenous GM1 ganglioside.
- 出版日期2009-12
