scholarly journals Role of endogenous CYP450 metabolites of arachidonic acid in maintaining the glomerular protein permeability barrier

2007 ◽  
Vol 293 (2) ◽  
pp. F501-F505 ◽  
Author(s):  
Jan Michael Williams ◽  
Mukut Sharma ◽  
Siddam Anjaiahh ◽  
John R. Falck ◽  
Richard J. Roman
Keyword(s):  
Arachidonic Acid ◽  
Essential Role ◽  
Dienoic Acid ◽  
Permeability Barrier ◽  
Selective Inhibitors ◽  
Glomerular Permeability ◽  
Isolated Glomeruli ◽  
Cytochrome P 450 ◽  
Protein Permeability

This study examined the metabolism of arachidonic acid (AA) by cytochrome P-450 enzymes in isolated glomeruli and the effects of selective inhibitors of the synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatetraenoic acids (EETs) on glomerular permeability to albumin ( Palb). Glomeruli avidly produced 20-HETE, EETs, dihydroxyeicosatetraenoic acids (diHETEs), and HETEs when incubated with exogenous AA. N-hydroxy- N′-(4-butyl-2-methylphenyl)formamidine (HET0016; 10 μM) selectively inhibited the formation of 20-HETE by 95% and increased Palb from 0.00 ± 0.08 to 0.73 ± 0.10 ( n = 43 glomeruli, 4 rats). Addition of a 20-HETE mimetic, 20-hydroxyeicosa-5( Z),14( Z)-dienoic acid (20-5,14-HEDE; 1 μM) opposed the effects of HET0016 (10 μM) to increase Palb (0.21 ± 0.10, n = 36 glomeruli, 4 rats). Preincubation of glomeruli with exogenous AA to increase basal production of 20-HETE had a similar effect. We also examined the effect of an epoxygenase inhibitor, N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MSPPOH; 5 μM), on Palb. MSPPOH (5 μM) significantly increased Palb but had no effect on the synthesis of EETs in glomeruli incubated with AA. However, MSPPOH (5 μM) selectively reduced epoxygenase activity by 50% in glomeruli incubated without added AA. Pretreatment with 8,9-EET (100 nM) attenuated the effects of MSPPOH (5 μM) on Palb. These results indicate that glomeruli produce 20-HETE, EETs, diHETEs, and HETEs and that endogenously formed 20-HETE and EETs play an essential role in the maintenance of the glomerular permeability barrier to albumin.

scholarly journals 20-HETE modulates myogenic response of skeletal muscle resistance arteries from hypertensive Dahl-SS rats

2001 ◽  
Vol 280 (3) ◽  
pp. H1066-H1074 ◽  
Author(s):  
Jefferson C. Frisbee ◽  
Richard J. Roman ◽  
U. Murali Krishna ◽  
John R. Falck ◽  
Julian H. Lombard
Keyword(s):  
Skeletal Muscle ◽  
Arachidonic Acid ◽  
Dienoic Acid ◽  
Vessel Diameter ◽  
Transmural Pressure ◽  
Myogenic Response ◽  
Hydroxyeicosatetraenoic Acid ◽  
Resistance Arteries ◽  
Cytochrome P 450

The present study determined the role of 20-hydroxyeicosatetraenoic acid [20-HETE; produced by ω-hydroxylation of arachidonic acid via cytochrome P-450 (CP450) 4A enzymes] in regulating myogenic activation of skeletal muscle resistance arteries from normotensive (NT) and hypertensive (HT) Dahl salt-sensitive (SS) rats. Gracilis arteries (GA) were isolated from each rat and viewed via television microscopy, and changes in vessel diameter with altered transmural pressure were measured with a video micrometer. Under control conditions, GA from both groups exhibited strong, endothelium-independent myogenic activation. Treatment of GA with 17-octadecynoic acid (17-ODYA; inhibitor of CP450 4A enzymes) did not alter myogenic activation in NT rats, but impaired this response in HT animals. Treatment of GA from HT rats with dibromo-dodecynyl-methylsulfimide (DDMS; inhibitor of 20-HETE production) impaired myogenic activation, as did application of 20-hydroxyeicosa-6( Z),15( Z)-dienoic acid, an antagonist for 20-HETE receptors. Application of iberiotoxin, a Ca2+-activated potassium (KCa) channel inhibitor, restored myogenic activation from HT rats treated with DDMS. These results suggest that myogenic activation of skeletal muscle resistance arteries from NT Dahl-SS rats does not depend on CP450, whereas myogenic activation of these vessels in HT Dahl-SS rats is partly a function of 20-HETE production, inhibiting KCachannels through a receptor-mediated process.

Role of PGI2 and epoxyeicosatrienoic acids in relaxation of bovine coronary arteries to arachidonic acid

1993 ◽  
Vol 264 (2) ◽  
pp. H327-H335 ◽  
Author(s):  
M. Rosolowsky ◽  
W. B. Campbell
Keyword(s):  
Arachidonic Acid ◽  
Coronary Arteries ◽  
Vascular Tone ◽  
Epoxyeicosatrienoic Acids ◽  
Lipoxygenase Inhibitor ◽  
Physiological Processes ◽  
Coronary Vascular Tone ◽  
Cytochrome P 450 ◽  
Endothelium Dependent Relaxation

Metabolites of arachidonic acid regulate several physiological processes, including vascular tone. The purpose of this study was to determine which metabolites of arachidonic acid are produced by bovine coronary arteries and which may regulate coronary vascular tone. Arachidonic acid induced a concentration-related, endothelium-dependent relaxation [one-half maximum effective concentration (EC50) of 2 x 10(-7) M and a maximal relaxation of 91 +/- 2% at 10(-5) M] of bovine coronary arteries that were contracted with U-46619, a thromboxane mimetic. The concentration of 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), a metabolite of prostaglandin I2 (PGI2), increased from 82 +/- 6 to 328 +/- 24 pg/ml with arachidonic acid (10(-5) M). Treatment with the cyclooxygenase inhibitor indomethacin attenuated arachidonic acid-induced relaxations by approximately 50% and blocked the synthesis of 6-keto-PGF1 alpha. PGI2 caused a concentration-related relaxation (EC50 of 10(-8) M and a maximal relaxation of 125 +/- 11% at 10(-7) M). BW755C, a cyclooxygenase and lipoxygenase inhibitor, inhibited arachidonic acid-induced relaxation to the same extent as indomethacin. When vessels were treated with both indomethacin and BW755C, the inhibition of relaxation was the same as either inhibitor alone. SKF 525a, a cytochrome P-450 inhibitor, reduced arachidonic acid-induced relaxation by approximately 50%. When SKF 525a was given in combination with indomethacin, the relaxation by arachidonic acid was almost completely inhibited. SKF 525a inhibited the synthesis of epoxyeicosatrienoic acids (EETs).(ABSTRACT TRUNCATED AT 250 WORDS)

Fluorescent HPLC assay for 20-HETE and other P-450 metabolites of arachidonic acid

2000 ◽  
Vol 279 (2) ◽  
pp. H863-H871 ◽  
Author(s):  
Kristopher G. Maier ◽  
Lisa Henderson ◽  
Jayashree Narayanan ◽  
Magdalena Alonso-Galicia ◽  
John R. Falck ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Interstitial Fluid ◽  
Internal Standard ◽  
Dienoic Acid ◽  
Renal Tissue ◽  
Gas Chromatography Mass Spectrometry ◽  
Epoxyeicosatrienoic Acids ◽  
Hplc Assay ◽  
Standard Curve ◽  
Cytochrome P 450

This study describes a fluorescent HPLC assay for measuring 20-hydroxyeicosatetraenoic acid (20-HETE) and other cytochrome P-450 metabolites of arachidonic acid in urine, tissue, and interstitial fluid. An internal standard, 20-hydroxyeicosa-6( Z),15( Z)-dienoic acid, was added to samples, and the lipids were extracted and labeled with 2-(2,3-naphthalimino)ethyl trifluoromethanesulfonate. P-450 metabolites were separated on a C18 reverse-phase HPLC column. Coelution and gas chromatography-mass spectrometry studies confirmed the identity of the 20-HETE peak. The 20-HETE peak can be separated from those for dihydroxyeicosatrienoic acids, other HETEs, and epoxyeicosatrienoic acids. Known amounts of 20-HETE were used to generate a standard curve (range 1–10 ng, r 2 = 0.98). Recovery of 20-HETE from urine averaged 95%, and the intra-assay variation was <5%. Levels of 20-HETE were measured in 100 μl of urine and renal interstitial fluid or 0.1 mg of renal tissue. The assay was evaluated by studying the effects of 1-aminobenzotriazole (ABT) on the excretion of 20-HETE in rats. ABT reduced excretion of 20-HETE by >65% and inhibited the formation of 20-HETE by renal microsomes. The availability of this assay should facilitate work in this field.

scholarly journals Arachidonic acid activates phospholipase D in human neutrophils; essential role of endogenous leukotriene B4and inhibition by adenosine A2Areceptor engagement

2003 ◽  
Vol 73 (4) ◽  
pp. 530-539 ◽  
Author(s):  
Sonya Grenier ◽  
Nicolas Flamand ◽  
Julie Pelletier ◽  
Paul H. Naccache ◽  
Pierre Borgeat ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase D ◽  
Essential Role ◽  
Human Neutrophils

Respiratory epithelium modulates the responses of canine bronchi to cooling

1993 ◽  
Vol 74 (5) ◽  
pp. 2421-2425 ◽  
Author(s):  
Y. Gao ◽  
P. M. Vanhoutte
Keyword(s):  
Arachidonic Acid ◽  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Isometric Force ◽  
Nordihydroguaiaretic Acid ◽  
Respiratory Epithelium ◽  
Resting Tension ◽  
Cytochrome P 450 ◽  
Evoked Contractions

The present study was designed to investigate the effect of cooling on the modulatory role of the respiratory epithelium on the underlying smooth muscle. Canine bronchial rings and segments (with or without epithelium) were suspended in organ chambers and perfused with modified Krebs-Ringer bicarbonate solution, respectively. Isometric force was recorded. Cooling did not affect the resting tension of the bronchi. During contractions to carbachol, cooling evoked contractions in bronchi with epithelium but relaxations in those without epithelium. In the presence of indomethacin, cooling induced contractions in both preparations with and without epithelium. The contractions in bronchi with epithelium were significantly larger than those in bronchi without epithelium. After treatment with indomethacin, exogenous arachidonic acid potentiated the cooling-induced contractions in preparations with epithelium but not in those without epithelium. This potentiation was not affected by nordihydroguaiaretic acid. SKF 525-A and metyrapone, inhibitors of cytochrome P-450 monooxygenases, converted the cooling-induced contractions of preparations with epithelium to relaxations and had no significant effects on the responses of preparations without epithelium. These observations suggest that cooling induces from the epithelium the release of a cytochrome P-450-derived eicosanoid that potentiates contractions of the underlying airway smooth muscle to carbachol.

Role of cytochrome P-450 in endogenous antipyresis

2000 ◽  
Vol 279 (2) ◽  
pp. R455-R460 ◽  
Author(s):  
Wieslaw Kozak ◽  
Matthew J. Kluger ◽  
Anna Kozak ◽  
Maciej Wachulec ◽  
Karol Dokladny
Keyword(s):  
Arachidonic Acid ◽  
Intraperitoneal Administration ◽  
Dependent Manner ◽  
Epoxyeicosatrienoic Acid ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Rats And Mice ◽  
Dose Dependent ◽  
Cytochrome P 450

In previous reports, we (15, 18) and others (29) demonstrated data showing that various inhibitors of cytochrome P-450/epoxygenase augment fever in rats and mice, indicating that the enzyme may be involved in endogenous antipyresis. The aim of this study was to further test the hypothesis that the P-450-dependent epoxygenase pathway of arachidonic acid is part of the homeostatic system to control the height of fever. Sprague-Dawley rats were implanted with biotelemeters to monitor body temperature. Fever was induced by intraperitoneal injection of lipopolysaccharide (LPS; 80 μg/kg). We demonstrate that intraperitoneal administration of P-450 inducers (bezafibrate and dehydroepiandrosterone, 10 and 100 mg/kg) before LPS reduced fever in rats in a dose-dependent manner. In complementary experiments, rats were implanted with brain cannulas in addition to the biotelemeters. Various isomers of epoxyeicosanoids were administered into the lateral ventricle at doses of 0.01 to 10 μg/rat to test their influence on LPS-induced fever in rats. Four of five isomers were antipyretic in a dose-dependent manner. The most potent antipyretic isomers were 11,12-epoxyeicosatrienoic acid (EET) followed by 14,15-EET, 8,9-EET, and 12(R) hydroxyeicosatetraenoic acid. These data support the hypothesis that the cytochrome P-450/epoxygenase pathway of arachidonate metabolism is part of the endogenous antipyretic system.

Role of cytochrome P-450 4A in oxygen sensing and NO production in rat cremaster resistance arteries

1999 ◽  
Vol 277 (4) ◽  
pp. H1546-H1552 ◽  
Author(s):  
Cornel J. M. Kerkhof ◽  
Erik N. T. P. Bakker ◽  
Pieter Sipkema
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Arachidonic Acid Metabolism ◽  
No Production ◽  
Cremaster Muscle ◽  
Resistance Arteries ◽  
Arterial Diameter ◽  
Spontaneous Tone ◽  
Cytochrome P 450

The role of arachidonic acid metabolism and nitric oxide (NO) in hypoxia-induced changes of vascular tone was investigated in first-order cannulated rat cremaster muscle resistance arteries. Spontaneous tone reduced arterial diameter from 179 ± 2 μm (fully dilated) to 98 ± 3 μm under normoxia ([Formula: see text] = 150 mmHg). Hypoxia ([Formula: see text] 5–10 mmHg) had no significant effect on arterial diameter under conditions of spontaneous tone. The effect of hypoxia was not changed after blockade of cyclooxygenase with indomethacin or after blockade of lipoxygenase with nordihydroguaiaretic acid. However, after partial blockade of cytochrome P-450 4A enzymes with 17-octadecynoic acid (17-ODYA), hypoxia increased the diameter by 65 ± 6 μm ( P < 0.05). This increase could be inhibited by N G-nitro-l-arginine (l-NNA) or 20-hydroxyeicosatetraenoic acid (20-HETE). 17-ODYA induced a concentration-dependent dilation under normoxia, which could be blocked by endothelium removal orl-NNA. 17-ODYA did not increase smooth muscle sensitivity to NO. We conclude that, under conditions of spontaneous tone and in the absence of luminal flow, hypoxia (5–10 mmHg) has no effect on the diameter of resistance arteries from the rat cremaster muscle. Inhibition of the cytochrome P-450 4A pathway of arachidonic acid metabolism under normoxia induces NO production by the endothelium. Hypoxia induces an NO-mediated dilation when cytochrome P-450 4A enzymes are partially inhibited.

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