Martentoxin, a large-conductance Ca2＋-activated K＋ channel inhibitor, attenuated TNF-α-induced nitric oxide release by human umbilical vein endothelial cells

摘要

Martentoxin,a 4,046 Da polypeptide toxin purified from the venom of the scorpion Buthus martensii Karsch,has been demonstrated to block large-conductance Ca2+-activated K+(BKCa)channels;however,its biological roles are still largely unknown.In the present study,we investigated the pharmacological effects of martentoxin on regulating the production of nitric oxide induced by TNF-αin human umbilical vein endothelial cells(HUVECs).We found that,1,10 and 100μmol/L martentoxin decreased nitric oxide production by HUVECs exposed to 10 ng/mL TNF for 6,12 and 24 hours.We further demonstrated that martentoxin inhibited the activity of iNOS and retarded the down-regulation of eNOS mRNA induced by TNF-α.Therefore,martentoxin could be a potential therapeutic agent for vascular diseases.