Endothelial nitric oxide synthase (eNOS) uncoupling is a mechanism that leads to endothelial dysfunction. Previously, we reported shear stress-induced release of in vessels aged rats was significantly reduced and accompanied by increased production superoxide (18, 27). In the present study, investigated influence aging on eNOS uncoupling. Mesenteric arteries were isolated from young (3 mo) (24 C57 BL/6J mice. The expression protein vs. mice not different. However, had remarkable increases...

We have studied the effect of changes in shear stress on diameter isolated arterioles rat cremaster muscle. The steady-state active at a constant perfusion pressure (60 mm Hg) was 80 +/- 1.2 microns. vessels' passive (Ca(2+)-free solution) 156 1.8 Changes were induced either by an increase flow (velocity) or viscosity solution. At pressure, stepwise (0-80 microliters/min 10-microliters/min steps) elicited, with delay approximately 20 seconds, gradual up to 46%. 20-microliters/min rate,...

Abstract Endothelium-dependent responses are depressed in coronary and peripheral blood vessels after the onset of pacing-induced heart failure dogs various etiologies humans. The present study was designed to examine whether these were due decreases expression endothelial cell NO synthase (ecNOS) cyclooxygenase-1 (COX-1). After 1 month left ventricular pacing, 8 mongrel monitored for as defined by clinical signs end diastolic pressures >25 mm Hg. Total RNA protein isolated from cells...

Abstract We aimed to test the hypothesis that as a consequence of short-term daily exercise, flow (shear stress)–dependent dilation and its mediation by endothelium are altered in skeletal muscle arterioles. After initial familiarization with protocol, rats ran on treadmill once day (with gradually increasing intensity up 40 minutes 28 m/min) for ≈3 weeks (EX group); control group remained sedentary (SED group). The active (internal) diameters isolated gracilis arterioles SED EX at 80 mm Hg...

We have studied the mechanisms responsible for mediation of flow (shear stress)-induced dilation isolated arterioles rat gracilis muscle. Active diameter at a constant perfusion pressure (PP, 80 mmHg) was approximately 92 microns, while their passive (Ca(2+)-free solution) 165 microns. At PP stepwise increase in solution (PS, 0-60 microliters/min 10-microliters/min steps) elicited gradual up to 140 Flow-induced dilations were eliminated by removal endothelium (by air). Dilations...

We aimed to test the hypothesis that as a consequence of short-term daily bouts exercise control arteriolar smooth muscle by endothelium is altered. Rats ran on treadmill once day, 5 days/wk, for 2–4 wk (with gradually increasing intensity, up 26 min at 22 m/min 1% grade beginning 3rd and 38 28 2% 4th wk) while group remained sedentary (SED). Cannulated pressurized arterioles rat gracilis developed spontaneous myogenic tone, which was slightly enhanced in exercised (EX) compared with SED...

Nitric oxide and prostaglandins were shown to contribute the endothelial mediation of flow-induced dilation skeletal muscle arterioles rats. Thus, we hypothesized that its are altered in gracilis mice deficient gene for nitric synthase (eNOS-KO) compared with control wild-type (WT) mice. Gracilis ( approximately 80 micrometer) male isolated, then cannulated pressurized a vessel chamber. The increases diameter elicited by perfusate flow from 0 10 microq/min similar eNOS-KO (n=28) WT (n=22) 20...

We hypothesized that aging is characterized by a reduced release of nitric oxide (NO) in response to shear stress resistance vessels. Mesenteric arterioles and arteries young (6 mo) aged (24 male Fischer 344 rats were isolated cannulated. Shear (15 dyn/cm(2))-induced dilation was significantly (1, 5, 10, 15 increases perfusate nitrite smaller at all levels vessels rats. Inhibition NO synthesis abolished stress-induced nitrite. Furthermore, nitrate higher total (nitrite plus nitrate) lower...

The aims of the present study were to determine response rat cremaster muscle first-order arterioles hypoxia and role endothelium-derived prostaglandins in response. Isolated cannulated, pressurized 65 mm Hg, studied a no-flow condition bath containing Krebs' bicarbonate solution, pH 7.4, equilibrated with 21% O2-5% CO2-74% N2 (PO2, 150 Hg) or 95% N2-5% CO2 15 Hg [hypoxia]). Responses vasoactive substances before after removal endothelium blockade prostaglandin synthesis by administration...

The mechanisms that account for acetylcholine (ACh)-induced responses of skeletal muscle arterioles mice lacking endothelial nitric oxide (NO) synthase (eNOS-KO) were investigated. Isolated, cannulated, and pressurized gracilis from male eNOS-KO (74.1 ± 2.3 μm) wild-type (WT, 87.2 2.1 developed spontaneous tone accounting 63 61% their passive diameter (116.8 3.4 vs. 143.2 2.8 μm, respectively) dilated dose-dependently to ACh (10 − 9 -10 7 M). These dilations significantly smaller in vessels...

Abstract —It is thought that elevated levels of reactive oxygen metabolites contribute to the dysfunction vascular endothelium in hypertension. We hypothesized high intravascular pressure itself elicits production superoxide, which then interferes with nitric oxide (NO)–mediated responses arterioles. Thus, isolated arterioles (≈80 μm diameter) from gracilis muscle normotensive Wistar rats were cannulated and exposed 140 mm Hg perfusion for 30 minutes (in absence perfusate flow). After...

Vasodilation to increases in flow was studied isolated gracilis muscle arterioles of female endothelial nitric oxide synthase (eNOS)-knockout (KO) and wild-type (WT) mice. Dilation (0–10 μl/min) similar the two groups, yet calculated wall shear stress significantly greater eNOS-KO than WT Indomethacin, which inhibited flow-induced dilation vessels mice by ∼40%, did not affect responses mice, whereas miconazole 6-(2-proparglyoxyphenyl)hexanoic acid (PPOH) abolished responses. Basal release...

Flow-induced dilation was examined in isolated coronary arteries of endothelial nitric oxide (NO) synthase knockout mice (eNOS-KO) and wild-type (WT) mice. The basal tone (percentage passive diameter) significantly greater eNOS-KO than WT mice; their flow-induced dilations, however, were similar. Endothelial removal eliminated the dilations vessels both strains In mice, N(omega)-nitro-L-arginine methyl ester (L-NAME) (10(-4) M) or indomethacin (10(-5) alone, inhibited by approximately 50%,...

We hypothesized that shear stress stimulates the release of epoxyeicosatrienoic acids (EETs) from arteriolar endothelium, which directly hyperpolarize smooth muscle. To test this hypothesis, a perfusion system, consisting two separate, serially connected chambers (A and B), was used. A donor vessel, isolated gracilis muscle female NO-deficient mice rats, cannulated in chamber A. In B, an endothelium-denuded detector vessel mesentery these animals cannulated. presence indomethacin, 5, 10, 20...

The characteristics of arteriolar myogenic responses female rats have not been investigated. Thus experiments were conducted on isolated gracilis muscle arterioles (approximately 55 microm diameter) four groups 12-wk-old rats: male rats, ovariectomized with no estrogen replacement (OV), and (OV + E2, 50 microg/kg s.c. injection 17beta-estradiol benzoate every 48 h). Diameter changes in response to increases perfusion pressure from 20 140 mmHg various concentrations substance P (SP, 10(-9)-5...

Responses to changes in intravascular pressure of isolated rat mesenteric arterioles were investigated under no-flow conditions. First-, second-, third-, and fourth-generation cannulated. Vascular diameters measured with an image-shearing device recorded. The (except for the first-generation vessels) developed spontaneous tone, corresponding step increases (from 20 160 mmHg, by 20-mmHg steps). For example, at 80 mmHg mean first-, vessels 286.9 +/- 5.0, 203.4 8.2, 92.5 4.6, 35.6 4.8 microns,...

Responses to changes in intravascular pressure of isolated rat gracilis muscle arterioles were investigated under no-flow conditions. First-, second-, and third- order cannulated. Vascular diameters measured with an image-shearing device then recorded. In response the step increases perfusion (from 20 160 mmHg, by 10- or 20-mmHg steps) constricted developed active tone. For example, at 100, 80, 50 mmHg steady-state 1st-, 2nd-, 3rd-order 76.9 +/- 1.6, 32.3 1.1 22.3 3.2 microns, respectively....

Abstract Obesity is a major risk factor for number of chronic diseases, including diabetes, cardiovascular and cancer. Expansion the adipose mass requires adipocyte precursor cells that originate from multipotent adipose-derived stromal (ASCs), which in turn also participate repair activities. ASC function might decline disease milieu, but it remains unclear whether varies during development obesity. We tested hypothesis microenvironmental inflammatory changes metabolic disorders obesity...

Previous studies show that agonist-induced, nitric oxide (NO)-mediated arteriolar dilations are greater in female than male rats. Thus we hypothesized flow-dependent dilation, which is part mediated by NO, also females males. Gracilis muscle arterioles from 12-wk-old and Wistar rats were isolated, cannulated, pressurized. At 80 mmHg of perfusion pressure, the active diameter passive (PD) 58.3 +/- 3.4 53.2 2.6 micrometer as well 103.6 4.0 115.3 4.8 micrometer, respectively. Dilations to step...

Background —Endothelial nitric oxide (NO)–mediated responses are impaired in arterioles of male spontaneously hypertensive rats (SHR), but they still present female SHR. We hypothesized that vitro incubation SHR with estrogen will restore NO-mediated by upregulation endothelial NO synthase. Methods and Results —Responses to increases perfusate flow (from 0 25 μL/min) the calcium ionophore A23187 (5×10 −8 10 −6 mol/L), norepinephrine (NE; −7 3×10 sodium nitroprusside (SNP; adenosine (ADO;...