ASCORBATE INHIBITS THE ENDOTHELIUM-DEPENDENT HYPERPOLARIZATION MEDIATED RELAXATION IN RESISTANCE ARTERIES
BOGDAN HUZUM, DRAGOMIR NICOLAE ŞERBAN *, IONUŢ TUDORANCEA, RADU ILIESCU, ANCA GALACTION, IONELA LĂCRĂMIOARA ŞERBAN
“Grigore T. Popa University” of Medicine and Pharmacy Iaşi, 16 Universităţii Street, 700115 Iași, România
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The main path of endothelium-dependent relaxation (EDR) in resistance arteries is independent of nitric oxide synthase and cyclooxygenase and is mediated by endothelium-dependent hyperpolarisation (EDH). We tested the effect of ascorbate upon this path in isolated small mesenteric arteries from the rat. EDR was induced by carbachol 10-5 M, in rings contracted by phenylephrine 10-5 M or by prostaglandin F2α 10-5 M, in the presence of L-N()-Nitro arginine methyl ester (l-NAME) 10-4 M and indomethacin 10-5 M. EDR proved to be reduced by ascorbate concentrations ranging between 10-5 M - 10-3 M (n = 6; p < 0.01). We discuss this new effect in the context of the relations between ascorbate and endothelial function/dysfunction