Thirty patients who had undergone coronary artery bypass grafting and who required vasodilator therapy for control of arterial hypertension were allocated to receive either low-dose or high-dose enoximone or placebo infusions. A closed-loop arterial pressure control system was used to assess cardiovascular stability and the amount of sodium nitro-prusside required to maintain control. There were no significant differences between the three groups in the time spent at 10, 20 and 30 mm Hg below the target pressure or at 10 and 20 mm Hg above the target pressure. However, the low-dose enoximone group spent a statistically greater amount of time at 30 mm Hg above the target pressure. There were no significant differences in the amount of sodium nitroprusside required to maintain control, in the duration of sodium nitroprusside infusion or in the heart rate. In conclusion, enoximone was not associated with a clinically significant effect on systolic pressure.
Our recent work showed that nitric oxide (NO)‐dependent sweating and cutaneous vasodilation are diminished in young males during intermittent exercise at high (700 W) relative to moderate (400 W) rates of metabolic heat production. We tested the hypothesis that this impairment results from increased oxidative stress during high intensity exercise. On separate days, nine young (24 ± 2 years) healthy males performed two 30 min bouts of semi‐recumbent cycling in the heat (35°C, 20% RH) at a rate of metabolic heat production of i) 500 W or ii) 700 W. The first and second exercise bouts were followed by 20 and 40 min of recovery, respectively. Forearm local sweat rate (LSR) and cutaneous vascular conductance (CVC) were measured at 4 skin sites that were continuously perfused via intradermal microdialysis with: 1) lactated Ringer's solution (Control), 2) 10 mM ascorbate (ASC, antioxidant), 3) 10 mM L‐NG‐Nitroarginine methyl ester (L‐NAME, non‐selective NO synthase inhibitor), or 4) 10 mM ASC + 10 mM L‐NAME. During moderate intensity exercise (i.e., 500 W), L‐NAME and ASC + L‐NAME reduced LSR and CVC compared to the Control site (all P < 0.05), while no effect of ASC was observed (all P > 0.05). Conversely, high intensity exercise performed at 700 W did not result in differences in LSR between treatment sites (P = 0.85). However, compared to Control, CVC was elevated at the ASC (all P < 0.05) while it was reduced at the L‐NAME (all P < 0.05) and ASC + L‐NAME (all P < 0.05) sites. Altogether these results suggest that oxidative stress impairs NO‐dependent cutaneous vasodilation but not LSR during intense exercise. Support: Natural Sciences and Engineering Research Council of Canada.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.