Search results for "Thromboxane"
showing 10 items of 64 documents
Different role of endothelin ETA and ETB receptors and endothelial modulators in diabetes-induced hyperreactivity of the rabbit carotid artery to end…
2004
The influence of diabetes on regulatory mechanisms and specific receptors implicated in the contractile response of isolated rabbit carotid arteries to endothelin-1 was examined. Endothelin-1 induced a concentration-dependent contraction that was greater in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal or N(G)-nitro-L-arginine enhanced contractions in response to endothelin-1 only in control arteries, without modifying the endothelin-1 response in diabetic arteries. Indomethacin, furegrelate (thromboxane A(2) inhibitor), or cyclo-(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123; endothelin ET(A) receptor antagonist) inhibited the contractions in response to en…
Estradiol selectively stimulates endothelial prostacyclin production through estrogen receptor-α
2010
Estradiol (E2) acts on the endothelium to promote vasodilatation through the release of several compounds, including prostanoids, which are products of arachidonic acid metabolism. Among these, prostacyclin (PGI2) and thromboxane A2 (TXA2) exert opposite effects on vascular tone. The role of different estrogen receptors (ERs) in the PGI2/TXA2 balance, however, has not been fully elucidated. Our study sought to uncover whether E2 enhances basal production of PGI2 or TXA2 in cultured human umbilical vein endothelial cells (HUVECs), to analyze the enzymatic mechanisms involved, and to evaluate the different roles of both types of ERs (ERα and ERβ). HUVECs were exposed to E2, selective ERα (1,3…
Mechanisms underlying the diabetes-induced hyporeactivity of the rabbit carotid artery to atrial natriuretic peptide
2010
Abstract Atrial natriuretic peptide (ANP) plays an important role in the pathophysiology of the vascular complications in diabetes. The working hypothesis was that diabetes might modify the vascular actions of ANP in isolated rabbit carotid arteries and the mechanisms involved in these actions. ANP (10 −12 –10 −7 M) induced a relaxation of precontracted carotid arteries, which was lower in diabetic than in control rabbits. In arteries from both groups of animals, endothelium removal increased the ANP-induced relaxation. Isatin inhibited the relaxation to ANP both in arteries with and without endothelium. Carotid arteries from diabetic rabbits showed a decreased natriuretic peptide receptor…
Effects of zinc acexamate on blood flow and prostanoid levels in the gastric mucosa of the rat
1989
The effects of the new antiulcer compound zinc acexamate on blood flow and prostanoid levels in the gastric mucosa have been studied. Zinc acexamate (30 and 300 mg/kg) dose-dependently prevents the reduction induced by the perfusion of noradrenaline (3.5 micrograms/kg.min, 30 min) in gastric mucosal blood flow, as measured by 3H-aniline clearance. Zinc acexamate pretreatment also increases the levels of prostaglandin E2 in the gastric mucosa of the rat, both under control conditions and after infusion with noradrenaline. The levels of thromboxane A2 and prostacyclin were not modified by zinc acexamate. These results confirm the importance of microcirculation in pathogenesis and the idea tha…
Endothelin-1-induced potentiation of adrenergic responses in the rabbit pulmonary artery: role of thromboxane A(2).
2001
Abstract To examine whether low concentrations of endothelin-1 potentiate the vasocontrictor response to adrenergic stimulation, we recorded the isometric response of rings of rabbit pulmonary artery to electrical stimulation and noradrenaline. Endothelin-1 (10 −10 M) potentiated the contractions induced by electrical stimulation and noradrenaline. The endothelin ET B receptor antagonist (2,6-dimethylpiperidinecarbonyl-γ-methyl-Leu- N in -[Methoxycarbonyl]- d -Trp- d -Nle) (BQ-788, 10 −6 M), but not the endothelin ET A receptor antagonist cyclo( d -Asp-Pro- d -Val-Leu- d -TRP) (BQ-123, 10 −6 M), inhibited the potentiating effects of endothelin-1. Pretreatment with the cyclooxygenase inhibit…
Improvement of the circulatory function partially accounts for the neuroprotective action of the phytoestrogen genistein in experimental ischemic str…
2012
Abstract We tested the hypothesis that the phytoestrogen genistein protects the brain against ischemic stroke by improving the circulatory function in terms of reduced production of thromboxane A2 and leukocyte–platelet aggregates, and of preserved vascular reactivity. Ischemia-reperfusion (90 min-3 days, intraluminal filament) was induced in male Wistar rats, and functional score and cerebral infarct volume were the end points examined. Genistein (10 mg/kg/day) or vehicle (β-cyclodextrin) was administered at 30 min after ischemia or sham-operation. Production of thromboxane A2 and leukocyte–platelet aggregates, as well as reactivity of carotid artery to U-46619 (thromboxane A2 analogue) an…
Diabetes impairs the atrial natriuretic peptide relaxant action mediated by potassium channels and prostacyclin in the rabbit renal artery.
2012
Diabetes is associated with increased prevalence of hypertension, cardiovascular and renal disease. Atrial natriuretic peptide (ANP) plays an important role in cardiovascular pathophysiology and is claimed to have cardioprotective and renoprotective effect in diabetic patients. The working hypothesis was that alloxan-induced diabetes might modify the vascular effects of ANP in isolated rabbit renal arteries and the mechanisms involved in such actions. Plasma ANP levels were higher in diabetic rabbits than in control rabbits. ANP (10(-12)-10(-7)M) induced a relaxation of precontracted renal arteries, which was lower in diabetic than in control rabbits. In arteries from both groups of animals…
High-speed rotational angioplasty-induced echo contrast in vivo and in vitro optical analysis
1992
High-speed rotational angioplasty is being evaluated as an alternative interventional device for the endovascular treatment of chronic coronary occlusions. It has been postulated that this type of angioplasty device may produce particulate debris or cavitations that induce myocardial ischemia. To determine the clinical presence of myocardial ischemia during rotational angioplasty, echocardiographic monitoring for wall motion abnormalities was performed in 9 patients undergoing rotational atheroablation using the Auth Rotablator for 10-sec intervals at 150,000 and 170,000 rpm. No wall motion abnormalities were detected in 5 patients evaluated with transesophageal echocardiography or in 4 pat…
Eight-week consumption of milk enriched with omega 3 fatty acids raises their blood concentrations yet does not affect lipids and cardiovascular dise…
2014
Adequate concentrations of omega 3 fatty acids (FA) may be maintained by consuming foods naturally rich in or functional foods enriched with those essential FA. We assessed the effects of an 8-week consumption of milk enriched with 400. mg of omega 3 FA on blood lipid levels and selected cardiovascular risk factors in adult healthy volunteers. Participants (n= 157) were randomized to consume - for eight weeks - either 500. mL/day of 1% fat milk providing 150. mg of eicosapentaenoic (EPA), 150. mg of docosahexaenoic (DHA), and 100. mg of α-linolenic (ALA) acids or 500. mL/day of non-enriched 1% fat milk. At week 8, we observed significant increments of blood EPA and DHA in the intervention g…