Maternal high-sucrose diets altered vascular large-conductance Ca2+-activated K+ channels via reactive oxygen species in offspring rats†
Overnutrition during pregnancy could increase risks of cardiovascular diseases in late life. This study investigated whether and how reactive oxygen species (ROS) may influence functions of large-conductance Ca2+-activated K+ channels (BKCa) in the offspring exposed to prenatal high sucrose (HS). We found that prenatal HS diets significantly increased phenylephrine (PE)-induced vessel contractions in mesenteric arteries of the adult offspring. Pretreatment with iberiotoxin (BKCa blocker, IBTX) significantly increased PE-mediated vascular contractions in the control, not in the HS group. Electrophysiological studies demonstrated that BKCa current density and single-channel current were reduced in the vascular smooth muscle cells (VSMCs) of the HS offspring. The expression of BKCa alpha, beta1 subunits in mesenteric arteries was decreased in the HS offspring, indicating that both activity and number of BKCa channels in HS offspring were reduced. Superoxide production and NADPH oxidase (NOX)4 of the HS offspring were elevated. Following inhibiting NOX by apocynin, vasoconstriction in the HS offspring was weakened and the reduced currents in the VSMCs were improved with altered protein kinase B (AKT) pathway. The results suggested that NOX4-derived ROS might inhibit the offspring vascular BKCa channel activity via AKT pathway.