Mechanisms underlying the vasorelaxation of human internal mammary artery induced by (-)-epicatechin

摘要: Abstract Evidences have suggested that flavanol compound (-)-epicatechin is associated with reduced risk of cardiovascular diseases. One the mechanisms its cardioprotective effect vasodilation. However, exact by which causes vasodilation are not yet clearly defined. The aims present study were to investigate relaxant on isolated human internal mammary artery (HIMA) and determine underlying vasorelaxation. Our results showed induced a concentration-dependent relaxation HIMA rings pre-contracted phenylephrine. Among K + channel blockers, 4-aminopyridine (4-AP) margatoxin, blockers voltage-gated (K V ) channels, glibenclamide, selective ATP-sensitive ATP channels blocker, partly inhibited (-)-epicatechin-induced HIMA, while iberiotoxin, most blocker large conductance Ca 2+ -activated (BK ), almost completely relaxation. In 80 mM , partial whereas in -free medium, relaxed phenylephrine caffeine. Finally, thapsigargin, sarcoplasmic reticulum -ATPase inhibitor, slightly antagonized These suggest induces strong endothelium-independent whilst 4-AP- margatoxin-sensitive as well BK located vascular smooth muscle, mediate this addition, it seems could inhibit influx extracellular interfere intracellular release re-uptake reticulum.