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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)
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)
Male rats demonstrate persistent endothelium-dependent attenuation of vasoconstrictor reactivity following chronic hypoxia (CH). Since estrogen may interfere with hypoxia-induced gene expression, we hypothesized that gender differences exist in this response to CH. However, in conscious, instrumented rats, we found that CH resulted in a similar persistent(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)
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)
Attenuation of sympathetic vasoconstriction (sympatholysis) in working muscles during dynamic exercise is controversial. A potential mechanism is a reduction in alpha-adrenergic-receptor responsiveness. The purpose of this study was to examine alpha(1)- and alpha(2)-adrenergic-receptor-mediated vasoconstriction in resting and exercising skeletal muscle(More)
Human immunodeficiency virus (HIV)-associated pulmonary arterial hypertension (PAH) is a serious noninfectious disease involving an aberrant increase in pressure in the blood vessels of the lung, which leads to right ventricular (RV) heart failure and can eventually result in death. A lack of viable animal models of HIV-PAH has limited the identification of(More)
Chronic hypoxia (CH) is associated with both blunted agonist-induced and myogenic vascular reactivity, possibly due to an enhanced production of heme oxygenase (HO)-derived carbon monoxide (CO). However, the cellular location of the HO responsible for these effects has not been clearly established. Therefore, we examined the response to administration of(More)
Chronic hypoxia (CH)-induced pulmonary hypertension may influence basal endothelial cell (EC) intracellular Ca(2+) concentration ([Ca(2+)](i)). We hypothesized that CH decreases EC [Ca(2+)](i) associated with membrane depolarization and reduced Ca(2+) entry. To test this hypothesis, we assessed 1) basal endothelial Ca(2+) in pressurized pulmonary arteries(More)
The purpose of this study was to test the hypothesis that exercise training improves microvascular function in obese Zucker rats, a model of obesity and type II diabetes. Animals were divided into four age-matched groups: lean sedentary (LS), lean exercise (LE), obese sedentary (OS), and obese exercise (OE). The exercise groups were treadmill-exercised from(More)