Search results for "Lipases"
showing 10 items of 112 documents
Downregulation of nNOS and synthesis of PGs associated with endotoxin-induced delay in gastric emptying
2002
A single intraperitoneal injection of endotoxin (40 μg/kg) significantly delayed gastric emptying of a solid nutrient meal. Blockade of nitric oxide synthase (NOS) with 30 mg/kg ip N G-nitro-l-arginine methyl ester or 20 mg/kg ip 7-nitroindazole [neuronal NOS (nNOS) inhibitor] significantly delayed gastric emptying in control animals but failed to modify gastric emptying in endotoxin-treated rats. Administration of 2.5, 5, and 10 mg/kg ip N 6-iminoethyl-l-lysine [inducible NOS (iNOS) inhibitor] had no effect in either experimental group. Indomethacin (5 mg/kg sc), NS-398 (cyclooxygenase-2 inhibitor; 10 mg/kg ip), and dexamethasone (10 mg/kg sc) but not quinacrine (20 mg/kg ip) significantl…
Activation of P2Y receptors by ATP and by its analogue, ADPbetaS, triggers two calcium signal pathways in the longitudinal muscle of mouse distal col…
2008
Our previous research showed that ATP and adenosine 5'-O-2-thiodiphosphate (ADPbetaS) induce contractile effects in the longitudinal muscle of mouse distal colon via activation of P2Y receptors which are not P2Y(1) or P2Y(12) subtypes. This study investigated the nature of the P2Y receptor subtype(s) and the mechanisms leading to the intracellular calcium concentration increase necessary to trigger muscular contraction. Motor responses of mouse colonic longitudinal muscle to P2Y receptor agonists were examined in vitro as changes in isometric tension. ATP or ADPbetaS induced muscular contraction, which was not affected by P2Y(11) or P2Y(13) selective antagonists. Calcium-free solution or th…
Inhibition of phospholipase A2 activities and some inflammatory responses by the marine product ircinin
1996
The marine product ircinin has been tested for its effects on secretory and cytosolic phospholipase A2 (PLA2) activities in vitro as well as for inhibition of cellular functions in human neutrophils and inflammatory responses in mice. Ircinin inhibited Naja naja venom, human synovial recombinant, bee venom and zymosan-injected rat air pouch PLA2 with IC50 values in the microM range, similar to those of the known inhibitor scalaradial. On the other hand, ircinin was less active on cytosolic PLA2 from human monocytes and decreased potently the release of LTB4 in human neutrophils. This marine product affected weakly human neutrophil functions like superoxide generation and degranulation. In t…
A mouse model of in vivo chemical inhibition of retinal calcium-independent phospholipase A2 (iPLA2).
2013
International audience; Numerous studies have reported the implication of calcium-independent phospholipase A2 (iPLA2) in various biological mechanisms. Most of these works have used in vitro models and only a few have been carried out in vivo on iPLA2(-/-) mice. The functions of iPLA2 have been investigated in vivo in the heart, brain, pancreatic islets, and liver, but not in the retina despite its very high content in phospholipids. Phospholipids in the retina are known to be involved in several various key mechanisms such as visual transduction, inflammation or apoptosis. In order to investigate the implication of iPLA2 in these processes, this work was aimed to build an in vivo model of…
Adolescent binge‐ethanol accelerates cognitive impairment and β‐amyloid production and dysregulates endocannabinoid signaling in the hippocampus of A…
2019
Previous research in rodents suggests that the long‐term neurobehavioral disturbances induced by chronic ethanol (EtOH) exposure could be due to endocannabinoid system (ECS) alterations. Moreover, ECS failure has been proposed to mediate the cognitive impairment and β‐amyloid production in Alzheimer disease (AD). Thus, in the present study, we evaluated the effects of adolescent EtOH binge drinking on the cognitive disturbances, hippocampal β‐amyloid levels, and in the ECS expression on a transgenic mouse model (APP/PSEN, AZ) of AD. We exposed AZ and wild‐type mice to a binge‐drinking treatment during adolescence. At 6 and 12 months of age, we evaluated hippocampal‐dependent learning and me…
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…
Involvement of secretory phospholipase A2 activity in the zymosan rat air pouch model of inflammation.
1996
1. In the zymosan rat air pouch model of inflammation we have assessed the time dependence of phospholipase A2 (PLA2) accumulation in the inflammatory exudates as well as cell migration, myeloperoxidase activity, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. 2. A significant increase in PLA2 activity was detected in 1,200 g supernatants of exudates 8 h after injection of zymosan into rat air pouch. This event coincided with peaks in cell accumulation (mainly neutrophils) and myeloperoxidase activity in exudates and was preceded by a rise in eicosanoid levels. 3. This enzyme (without further purification) behaved as a secretory type II PLA2 with an optimum pH at 7-8 units, lack o…
Comparative changes between pancreas and pancreatic juice digestive enzyme contents during nutritional rehabilitation following severe protein malnut…
1993
The relationship between digestive enzyme activities in the pancreas and pancreatic juice was studied in post-weaning rats fed on a low-protein diet (30 g cereal protein/kg) for 1 month and a refeeding balanced diet (235 g mixed protein/kg) for the following 3 months. A control group was fed on the balanced diet for 4 months. At the end of malnutrition and at various times of refeeding, activities of amylase (EC3.2.1.1), trypsin(EC3.4.21.4), chymotrypsin (EC3.4.21.1), lipase (EC3.1.1.3), phospholipase A2 (EC3.1.1.4) and cholesterolesterase (EC3.1.1.13) in pancreas and pancreatic juice were measured. Recovery of body and pancreas weights was obtained after 3 months of refeeding. Pancreas off…
Bradykinin Contracts Rat Urinary Bladder Largely Independently of Phospholipase C
2014
Several receptor systems in the bladder causing detrusor smooth muscle contraction stimulate phospholipase C (PLC). PLC inhibition abolishes bladder contraction via P2Y6 but not that via M3 muscarinic receptors, indicating a receptor-dependent role of PLC. Therefore, we explored the role of PLC in rat bladder contraction by bradykinin. The PLC inhibitor U 73,122 [1-(6-[([17β]-3-methoxyestra-1,3,5[10]-trien-17-yl)-amino]hexyl)-1H-pyrrole-2,5-dione] did not affect the bradykinin response to a significantly greater degree than its inactive analog U 73,343 [10 μM each; 1-(6-[-([17β]-3-methoxyestra-1,3,5[10]-trien-17-yl)-amino]hexyl)-2,5-pyrrolidinedione], whereas the phospholipase D inhibitor b…
Release of choline from rat brain under hypoxia: contribution from phospholipase A2 but not from phospholipase D
1993
Moderate hypoxia induced in rats by inhalation of 10% oxygen led to an increase of the concentration of free choline in the brain and caused a large net-release of choline from the brain into the venous blood as determined by the measurement of the arterio-venous difference. In hippocampal slices from rat brain, hypoxia increased the release of choline into the superfusion medium. The activity of phospholipase D, as measured by the formation of phosphatidylpropanol in the presence of propanol, was not stimulated under these conditions. However, the mobilization of choline was completely depressed by lowering extracellular calcium and by 0.1 mM mepacrine. We conclude that hypoxia leads to a …