Effects of Kv7 channels on vasomotor function of human placental chorionic arteries

WEI Xiaohong; FU Xiaodong

doi:10.3969/j.issn.1002-266X.2017.16.008

Abstract：Objective To study the effects of Kv7 channels on the vasomotor function of human placental chorionic arteries (CPAs).Methods The vascular rings of CPAs with integrated or denuded endothelium were added with the cumulative concentrations of KCNQ channel blockers (XE991 and Linopirdine) or DMSO and we calculated the vasoconstriction.The endothelium-denuded vascular rings of CPAs were added with the cumulative concentrations of U46619 with or without the incubation of XE991, and we calculated the vasoconstriction.The endothelium-denuded vascular rings of CPAs were first treated with U46619 (10-7mol/L), and then were added with the cumulative concentrations of Kv7 channels openers [Acrylamide (S)-1, Retigabine, BMS-204352 and ML277] or DMSO, and we and we calculated the vasoconstriction.The endothelium-denuded vascular rings of CPAs were pretreated with nifedipine, levcromakalim and calcium-free liquid and then were added with XE991(10-5 mol/L) or Linopirdine (10-5 mol/L), at last, we calculated the vasoconstriction before and after treatment.Results The vasoconstrictions of vascular rings of CPAs with integrated or denuded endothelium increased with the increased concentrations of XE991 and Linopirdine (10-8-10-4 mol/L), and the highest vasoconstrictions apperated at 5×10-5 and 10-4 mol/L, which were higher than those treated with the same concentrations of DMSO (all P<0.01).No significant difference was found in the vasoconstriction of vascular rings treated with the same concentration of XE991or Linopirdine between the vascular rings of CPAs with integrated endothelium and vascular rings of CPAs with denuded endothelium (all P>0.05).With the increased concentrations of U46619, the vasoconstriction of endothelium-denuded vascular rings of CPAs with or without the incubation of XE991 increased gradually, and the increase was more significant after the incubation (all P<0.01).Acrylamide (S)-1, Retigabine, and BMS-204352 (10-4 mol/L) relaxed more the U46619-induced contraction of vascular rings of CPAs as compared with that of DMSO (all P<0.01), but ML277 had no effect on U46619-induced relaxation (all P>0.05).The vasoconstriction was lower after treatment of nifedipine, levcromakalim and calcium-free liquid as compared with that before treatment in the XE991 and Linopirdine groups (all P<0.01).Conclusion Kv7 channels (KCNQ) is involved in regulating CPAs tension by mediating the resting cell membrane K+ conductance and static rate of membrane potential changes, and has nothing to do with endothelial integrity.Blocking KCNQ channels can cause the depolarization of vascular smooth muscle cells, activate the L-type calcium channel, and cause calcium ion flow and vasoconstriction.