Interaction of nitric oxide and muscle contraction in adenosine-induced muscle vasodilation in humans

摘要: Adenosine (ADO) is one of several endogenous substances known to mediate muscle vasodilation during exercise. The purpose this study was examine (1) the role nitric oxide (NO) in ADO-mediated vasodilation; (2) magnitude blood flow (MBF) responses ADO infusion exercise; and (3) influence regulating heterogeneous MBF distribution. In healthy, young participants (N=14), local measured using near-infared spectroscopy indocyanine green (ICG) dye at two locations on vastus lateralis (VL). Cardiac output quantified a dye-dilution technique with ICG dye. Participants were tested rest 1-leg knee extension exercise (25W) under different conditions: control, (150mg·kg body mass -1 ·min ) ADO+NO blockade (L-NMMA; 1mg·kg ). At exercise, we found that mean VLBF increased from control decreased significantly ADO+L-NMMA infusion; exercising BF values always higher than rest. Additionally, infusion, peak increase oxy-hemoglobin concentration (O 2 Hb) reached within minutes initiating however differed between regions, indirectly indicating ADO-induced metabolic heterogeneity. O Hb subsequently over time, reaching stable level 5 min. Also, observed when elevated through usual exercise-mediated vasodilator signals are not down-regulated contraction demonstrating lack autoregulation. We conclude NO does playa mediating there autoregulatory feedback infused