Search results for "Prostanoid"
showing 7 items of 17 documents
Diabetes-induced changes in endothelial mechanisms implicated in rabbit carotid arterial response to 5-hydroxytryptamine
2000
Abstract The influence of diabetes on endothelial mechanisms implicated in the response of isolated rabbit carotid arteries to 5-hydroxytryptamine (5- HT ) was studied. 5-HT induced a concentration–dependent contraction that was potentiated in arteries from diabetic rabbits with respect to that in arteries from control rabbits. Endothelium removal potentiated 5-HT contractions in arteries from both control and diabetic rabbits but increased the maximum effect only in arteries from diabetic rabbits. Incubation of arterial segments with N G -nitro- l -arginine ( l- NA) enhanced the contractile response to 5-HT. This l -NA enhancement was greater in arteries from diabetic rabbits than in arter…
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…
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…
Experimental diabetes induces hyperreactivity of rabbit renal artery to 5-hydroxytryptamine.
2002
Abstract The influence of diabetes on the response of isolated rabbit renal arteries to 5-hydroxytryptamine (5-HT) was examined. 5-HT induced a concentration-related contraction that was higher in arteries from diabetic rabbits than in arteries from control rabbits. Endothelium removal did not significantly modify 5-HT contractions in arteries from control rabbits but enhanced the response to 5-HT in arteries from diabetic rabbits. Incubation with N G -nitro- l -arginine ( l -NA) enhanced contractions to 5-HT in arteries from control and diabetic rabbits. In arteries with endothelium, this l -NA enhancement was lower in diabetic rabbits than in control rabbits. In arteries without endotheli…
Prostanoid receptors of the EP3 subtype mediate inhibition of evoked [3 H]acetylcholine release from isolated human bronchi
1998
1 The release of neuronal [3H]acetylcholine (ACh) from isolated human bronchi after labelling with [3H]choline was measured to investigate the effects of prostanoids. 2 A first period of electrical field stimulation (S1) caused a [3H]ACh release of 320±70 and 200±40 Becquerel (Bq) g−1 in epithelium-denuded and epithelium-containing bronchi respectively (P>0.05). Subsequent periods of electrical stimulation (Sn, n=2, 3, and 4) released less [3H]ACh, i.e. decreasing Sn/S1 values were obtained (0.76±0.09, 0.68±0.07 and 0.40±0.04, respectively). 3 Cumulative concentrations (1–1000 nM) of EP-receptor agonists like prostaglandin E2, nocloprost, and sulprostone (EP1 and EP3 selective) inhibited ev…
Effects of the prostanoid EP3 -receptor agonists M&B 28767 and GR 63799X on infarct size caused by regional myocardial ischaemia in the anaesthet…
1999
1. This study investigates the effects of two agonists of the prostanoid EP3-receptor (MB PEEP: 1-2 mmHg) and subjected to occlusion of the left anterior descending coronary artery (LAD, for 7.5, 15, 25, 35, 45 or 60 min) followed by reperfusion (2 h). Infarct size was determined by staining of viable myocardium with a tetrazolium stain (NBT), histological evaluation by light and electron microscopy and determination of the plasma levels of cardiac troponin T. 3. MB saline-control, n=8) to 39+/-6 and 38+/-4% of the area at risk, without causing a significant fall in blood pressure. Pretreatment of rats with 5-hydroxydecanoate (5-HD), an inhibitor of ATP-sensitive potassium channels, attenua…
Prostanoid release of cultured liver sinusoidal endothelial cells in response to endotoxin and tumor necrosis factor
1990
Abstract Vascular endothelial cells release prostanoids, especially prostacyclin, when properly stimulated. In addition to short acting stimuli like thrombin and histamine an increased prostanoid release occurs in the presence of endotoxin, interleukin 1 or tumor necrosis factor (TNF). The response of sinusoidal endothelial liver cells to such stimuli — probably important in hepatic inflammatory disease — is unknown. Sinusoidal endothelial liver cells from the guinea pig were isolated by centrifugal elutriation and investigated as confluent monolayers. Their prostanoid release in response to endotoxin and human recombinant TNF was determined by radioimmunoassays and compared to that obtaine…