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To test the hypothesis that vasodilation occurs because of the release of a vasoactive substance after a brief muscle contraction and to determine whether acetylcholine spillover from the motor nerve is involved in contraction-induced hyperemia, tetanic muscle contractions were produced by sciatic nerve stimulation in anesthetized dogs (n = 16),(More)
We have previously shown that hydrogen sulfide (H₂S) reduces myogenic tone and causes relaxation of phenylephrine (PE)-constricted mesenteric arteries. This effect of H₂S to cause vasodilation and vascular smooth muscle cell (VSMC) hyperpolarization was mediated by large-conductance Ca(2+)-activated potassium channels (BKCa). Ca(2+) sparks are ryanodine(More)
Chronic hypoxia is associated with both blunted agonist-induced and myogenic vascular reactivity and is possibly due to an enhanced production of heme oxygenase (HO)-derived carbon monoxide (CO). However, the mechanism of endogenous CO-meditated vasodilation remains unclear. Isolated pressurized mesenteric arterioles from chronically hypoxic rats were(More)
Obesity, insulin resistance, dyslipidemia, and hypertension are components of the pathophysiological state known as metabolic syndrome. Adrenergic vasoconstriction is mediated through increases in cytosolic Ca2+ and the myofilaments' sensitivity to Ca2+. In many pathophysiological states, there is an enhanced role for Rho kinase (ROK)-mediated increases in(More)
Walker. Pressure-induced smooth muscle cell depolarization in pulmonary arteries from control and chronically hypoxic rats does not cause myogenic vasoconstriction. obstructive pulmonary diseases, as well as prolonged residence at high altitude, can result in generalized airway hypoxia, eliciting an increase in pulmonary vascular resistance. We hypothesized(More)
Carbon monoxide (CO) has been proposed to attenuate the vasoconstrictor response to local hypoxia that contributes to pulmonary hypertension. However, the segmental response to CO, as well as its mechanism of action in the pulmonary circulation, has not been fully defined. To investigate the hemodynamic response to exogenous CO, lungs from male(More)
These experiments tested the hypothesis that elevating muscle blood flow before exercise would wash out vasoactive substances produced by muscle contraction and reduce the magnitude of exercise hyperemia and/or delay the response. In chronically instrumented dogs (n = 7), hindlimb blood flow was measured with chronically implanted flow probes during mild(More)
Chronic hypoxia (CH) results in reduced sensitivity to vasoconstrictors in conscious rats that persists upon restoration of normoxia. We hypothesized that this effect is due to endothelium-dependent hyperpolarization of vascular smooth muscle (VSM) cells after CH. VSM cell resting membrane potential was determined for superior mesenteric artery strips(More)
Atrophic signaling elements of the ubiquitin–proteasome system (UPS) are involved in skeletal muscle wasting as well as pressure overload models of heart failure. In our prior experiments, we demonstrated a transcriptional downregulation of atrophy-inducing vascular E3 ubiquitin ligases in a toxic model of pulmonary hypertension where pulmonary artery and(More)
Software testing provides a means to minimize errors, cut maintenance and decrease overall software costs. Different software development and testing methodologies, tools, and techniques have emerged to enhance software quality. At each and every phase of software development life cycle testing is performed with different tools and techniques. One of the(More)