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BACKGROUND Sympathetic nervous system activity increases with exercise in normal subjects. Heightened peripheral sympathetic nervous activity and the resultant increased neurovascular levels of norepinephrine (NE) evoke vasoconstriction and serve to maintain blood pressure and perfusion to vital organs. Previous work demonstrated that the interstitial ATP(More)
Supplementary oxygen is commonly administered in current medical practice. Recently it has been suggested that hyperoxia causes acute oxidative stress and produces prompt and substantial changes in coronary resistance in patients with ischemic heart disease. In this report, we examined whether the effects of hyperoxia on coronary blood velocity (CBV) would(More)
Reactive oxygen species (ROS), produced acutely during skeletal muscle contraction, are known to stimulate group IV muscle afferents and accentuate the exercise pressor reflex (EPR) in rodents. The effect of ROS on the EPR in humans is unknown. We conducted a series of studies using ischemic fatiguing rhythmic handgrip to acutely increase ROS within(More)
BACKGROUND During exercise, the sympathetic nervous system is activated and blood pressure and heart rate increase. In heart failure (HF), the muscle metaboreceptor contribution to sympathetic outflow is attenuated and the mechanoreceptor contribution is accentuated. Previous studies suggest that (1) capsaicin stimulates muscle metabosensitive vanilloid(More)
We examined whether ATP stimulation of P2X purinoceptors would raise blood pressure in decerebrate cats. Femoral arterial injection of the P2X receptor agonist alpha,beta-methylene ATP into the blood supply of the triceps surae muscle induced a dose-dependent increase in arterial blood pressure. The maximal increase in mean arterial pressure (MAP) evoked by(More)
Obstructive apnea and voluntary breath holding are associated with transient increases in muscle sympathetic nerve activity (MSNA) and arterial pressure. The contribution of changes in blood flow relative to the contribution of changes in vascular resistance to the apnea-induced transient rise in arterial pressure is unclear. We measured heart rate, mean(More)
Previous studies have suggested that activation of ATP-sensitive P2X receptors in skeletal muscle play a role in mediating the exercise pressor reflex (Li J and Sinoway LI. Am J Physiol Heart Circ Physiol 283: H2636-H2643, 2002). To determine the role ATP plays in this reflex, it is necessary to examine whether muscle interstitial ATP (ATPi) concentrations(More)
  • D A Sterns, S M Ettinger, +4 authors L I Sinoway
  • 1991
BACKGROUND Resting sympathetic nervous system activity is increased in heart failure. Whether sympathetic nervous system responses during exercise are increased is controversial. Furthermore, the role of muscle metaboreceptors and central command in regulating sympathetic outflow has been largely unexplored. METHODS AND RESULTS Muscle sympathetic nerve(More)
Supplemental O2 reduces cardiac output and raises systemic vascular resistance in congestive heart failure. In this study, 100% O2 was given to normal subjects and peak forearm flow was measured. In experiment 1, 100% O2 reduced blood flow and increased resistance after 10 min of forearm ischemia (flow 56.7 +/- 7.9 vs. 47.8 +/- 6.7 ml.min-1.100 ml-1; P <(More)
Pathological formation of reactive oxygen species within the coronary circulation has been hypothesized to mediate some clinical manifestations of ischemic heart disease (IHD) by interfering with physiological regulation of coronary tone. To determine the degree to which coronary tone responds to acute changes in ambient levels of oxidants and antioxidants(More)