Mechanisms underlying obesity-related vascular dysfunction are unclear. This study examined the effect of diet-induced obesity on expression and function of large conductance Ca(2+)-activated potassium channel (BK(Ca)) in rat pressurized small resistance vessels with myogenic tone. Male Sprague-Dawley rats fed a cafeteria-style high fat diet (HFD; ∼30% energy from fat) for 16-20 wk were ∼30% he...

Cerebral blood vessels are critical in maintaining the health of the brain, but their function can be disrupted by traumatic brain injury (TBI). Even in cases without hemorrhage, vessels are deformed with the surrounding brain tissue. This subfailure deformation could result in altered mechanical behavior. This study investigates the effect of overstretch on the passive behavior of isolated mid...

Howitt L, Sandow SL, Grayson TH, Ellis ZE, Morris MJ, Murphy TV. Differential effects of diet-induced obesity on BKCa 1-subunit expression and function in rat skeletal muscle arterioles and small cerebral arteries. Am J Physiol Heart Circ Physiol 301: H29–H40, 2011. First published May 2, 2011; doi:10.1152/ajpheart.00134.2011.— Mechanisms underlying obesity-related vascular dysfunction are uncl...

We tested the hypothesis that lymphatics would exhibit myogenic constrictions and dilations to intraluminal pressure changes. Collecting lymphatic vessels were isolated from rat mesentery, cannulated, and pressurized for in vitro study. The lymphatic diameter responses to controlled intraluminal pressure steps of different magnitudes were tested in the absence and presence of the inflammatory m...

Vasodilatory responses to exogenous nitric oxide (NO) are diminished following exposure to chronic hypoxia (CH) in isolated, perfused rat lungs. We hypothesized that both endothelium-derived reactive oxygen species (ROS) and endothelin-1 (ET-1) mediate this attenuated NO-dependent pulmonary vasodilation following CH. To test this hypothesis, we examined vasodilatory and vascular smooth muscle (...

Increased intraluminal pressure can reduce endothelial function in resistance arterioles; however, the mechanism of this impairment is unknown. The purpose of this study was to determine the effect of local renin-angiotensin system inhibition on the pressure-induced blunting of endothelium-dependent vasodilation in human adipose arterioles. Arterioles (100-200 μm) were dissected from fresh adip...

Multi Jet Fusion™ (MJF) is a new proprietary form of Additive Manufacturing (AM) from Hewlett Packard (HP) developed to manufacture structures with design and functional complexity while simultaneously providing dramatic increase in the production rate relative other forms polymer-based AM. The increased now enabling more efficient mid-volume products, coupled additional benefits geometric free...

Whereas the actual identity of endothelium-derived hyperpolarizing factor (EDHF) is still not certain, it involves a process requiring the endothelium and eliciting hyperpolarization and relaxation of smooth muscle. It is neither nitric oxide (NO) nor prostacyclin, and its presence has been demonstrated in a variety of vessels. Recent studies in peripheral vessels report that EDHF-mediated dila...

The reactivity of porcine intramyocardial resistance arteries (223 +/- 7 micron i.d., n = 30) was investigated with a pressurized in vitro preparation. Diameter changes in response to acetylcholine and to adrenergic drugs and dynamic changes in transmural pressure changes were investigated. Acetylcholine produced concentration-dependent constrictions, causing maximal reductions of 71 +/- 3% in ...