Fig. 1.
Experimental timeline. After placement of the brachial artery catheter and general setup, subjects performed 15 min of rhythmic handgrip exercise (RHG) at 10% maximal voluntary contraction (MVC). Noted as trial 1, exercise was performed for 5 min with saline infusion to achieve “steady-state” hemodynamics. Ascorbic acid was administered concurrently throughout the next 10 min of exercise. The dose of ascorbic acid was then reduced to 40% of the original dose and infused for the remainder of the experiment. After 20 min of rest, trial 2 was performed, which consisted of another 15-min bout of exercise. After 5 min, either NG-monomethyl-l-arginine (l-NMMA) or ketorolac (Ket) was infused for 5 min. The other drug was infused for the last 5 min of exercise. Both l-NMMA and Ket were reduced to maintenance doses after trial 2. Subjects again rested for 20 min before trial 3, which consisted of 5 min of exercise. See text for further details.