Cytochrome P-450-dependent vasodilation of rat kidney by arachidonic acid

1991 ◽  
Vol 261 (3) ◽  
pp. H714-H719 ◽  
Author(s):  
A. O. Oyekan ◽  
J. C. McGiff ◽  
J. Quilley
Keyword(s):  
Arachidonic Acid ◽  
Cobalt Chloride ◽  
Stannous Chloride ◽  
Rat Kidney ◽  
Vasodilator Effect ◽  
Vasodilator Response ◽  
Cytochrome P 450 ◽  
Experimental Preparation ◽  
In Vivo Induction

Our previous studies indicated a role for cytochrome P-450-dependent enzymes in generating the mediators of the vasodilator effect of arachidonic acid (AA) in the preconstricted indomethacin-treated perfused kidney of the rat. We report that in vivo induction of cytochrome P-450 enzymes with 3-methylcholanthrene-beta-naphthoflavone or dexamethasone enhanced the renal vasodilator effect of AA in this experimental preparation. Conversely, depletion of cytochrome P-450 enzymes with stannous chloride or cobalt chloride diminished the vasodilator response to AA. Injection of AA resulted in the release of relaxant material into the renal effluent detected by superfusion of rabbit aortic rings. Inhibition of cytochrome P-450 with 7-ethoxyresorufin reduced the release of vasorelaxant material. Metabolism of labeled AA by the kidney revealed four peaks of radioactivity that were recovered from the renal effluent. The heights of these peaks were reduced by 7-ethoxyresorufin. These results provide further evidence for cytochrome P-450-dependent metabolism of AA to one or more vasodilator products by the rat kidney.

Dilation of cerebral arterioles by cytochrome P-450 metabolites of arachidonic acid

1990 ◽  
Vol 259 (4) ◽  
pp. H1171-H1177 ◽  
Author(s):  
E. F. Ellis ◽  
R. J. Police ◽  
L. Yancey ◽  
J. S. McKinney ◽  
S. C. Amruthesh
Keyword(s):  
Arachidonic Acid ◽  
Oxygen Radicals ◽  
Cyclooxygenase Inhibitors ◽  
Epoxyeicosatrienoic Acid ◽  
Cranial Window ◽  
Window Technique ◽  
Cerebral Arterioles ◽  
Pg E2 ◽  
Cytochrome P 450

We have recently shown that brain tissue can synthesize cytochrome P-450 monooxygenase metabolites of arachidonic acid (AA), including 5,6-epoxyeicosatrienoic acid (5,6-EET), and 14,15-EET. The purpose of this investigation was to determine the vasoactivity of EETs and AA on the cerebral microcirculation. Pial arteriolar diameter was measured in rabbits and cats using in vivo microscopy and the closed cranial window technique. Prostaglandin (PG) E2 and 6-keto-PGF1 alpha formed by the brain cortex during application of these fatty acids was measured in cerebrospinal fluid by use of radioimmunoassay. A transient dose-dependent dilation was produced by 5,6-EET (1-15 micrograms/ml), with the maximum being 23% of control in both species. Other EETs had little or no activity, and AA-induced dilation was greater in rabbits than in cats. Indomethacin or superoxide dismutase plus catalase prevented dilation by 5,6-EET and AA, indicating that both produce dilation via cyclooxygenase-dependent oxygen radicals. PGE2 and 6-keto-PGF1 alpha levels were increased by AA but not by EETs, implying that EETs do not directly activate AA metabolism. Since 5,6-EET, but not other EETs, is known to be a substrate for cyclooxygenase, our data are consistent with brain cyclooxygenase metabolism of 5,6-EET with concomitant generation of dilator oxygen radicals. An implication of these results is that many previous studies of the cerebral circulation which based conclusions on results with cyclooxygenase inhibitors may need to be additionally interpreted.

scholarly journals Arachidonic acid inhibits basolateral K channels in the cortical collecting duct via cytochrome P-450 epoxygenase-dependent metabolic pathways

2008 ◽  
Vol 294 (6) ◽  
pp. F1441-F1447 ◽  
Author(s):  
ZhiJian Wang ◽  
Yuan Wei ◽  
John R. Falck ◽  
Krishnam Raju Atcha ◽  
Wen-Hui Wang
Keyword(s):  
Arachidonic Acid ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Inhibitory Effect ◽  
K Channel ◽  
Dependent Manner ◽  
Cortical Collecting Duct ◽  
Patch Clamp Technique ◽  
K Channels ◽  
Cytochrome P 450

We used the patch-clamp technique to study the effect of arachidonic acid (AA) on basolateral 18-pS K channels in the principal cell of the cortical collecting duct (CCD) of the rat kidney. Application of AA inhibited the 18-pS K channels in a dose-dependent manner and 10 μM AA caused a maximal inhibition. The effect of AA on the 18-pS K channel was specific because application of 11,14,17-eicosatrienoic acid had no effect on channel activity. Also, the inhibitory effect of AA on the 18-pS K channels was abolished by blocking cytochrome P-450 (CYP) epoxygenase with N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide (MS-PPOH) but was not affected by inhibiting CYP ω-hydroxylase or cyclooxygenase. The notion that the inhibitory effect of AA was mediated by CYP epoxygenase-dependent metabolites was further supported by the observation that application of 100 nM 11,12-epoxyeicosatrienoic acid (EET) mimicked the effect of AA and inhibited the basolateral 18-pS K channels. In contrast, addition of either 5,6-, 8,9-, or 14,15-EET failed to inhibit the 18-pS K channels. Moreover, application of 11,12-EET was still able to inhibit the 18-pS K channels in the presence of MS-PPOH. This suggests that 11,12-EET is a mediator for the AA-induced inhibition of the 18-pS K channels. We conclude that AA inhibits basolateral 18-pS K channels by a CYP epoxygenase-dependent pathway and that 11,12-EET is a mediator for the effect of AA on basolateral K channels in the CCD.

scholarly journals Contribution of cytochrome P-450 4A1 and 4A2 to vascular 20-hydroxyeicosatetraenoic acid synthesis in rat kidneys

1999 ◽  
Vol 276 (2) ◽  
pp. F246-F253 ◽  
Author(s):  
Mong-Heng Wang ◽  
Hui Guan ◽  
Xuandai Nguyen ◽  
Barbara A. Zand ◽  
Alberto Nasjletti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Rat Kidney ◽  
Acid Synthesis ◽  
Biologically Active ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Antisense Odns ◽  
Cytochrome P 450

20-Hydroxyeicosatetraenoic acids (20-HETE), a biologically active cytochrome P-450 (CYP) metabolite of arachidonic acid in the rat kidney, can be catalyzed by CYP4A isoforms including CYP4A1, CYP4A2, and CYP4A3. To determine the contribution of CYP4A isoforms to renal 20-HETE synthesis, specific antisense oligonucleotides (ODNs) were developed, and their specificity was examined in vitro in Sf9 cells expressing CYP4A isoforms and in vivo in Sprague-Dawley rats. Administration of CYP4A2 antisense ODNs (167 nmol ⋅ kg body wt−1 ⋅ day−1iv for 5 days) decreased vascular 20-HETE synthesis by 48% with no effect on tubular synthesis, whereas administration of CYP4A1 antisense ODNs inhibited vascular and tubular 20-HETE synthesis by 52 and 40%, respectively. RT-PCR of microdissected renal microvessel RNA indicated the presence of CYP4A1, CYP4A2, and CYP4A3 mRNAs, and a CYP4A1-immunoreactive protein was detected by Western analysis of microvessel homogenates. Blood pressure measurements revealed a reduction of 17 ± 6 and 16 ± 4 mmHg in groups receiving CYP4A1 and CYP4A2 antisense ODNs, respectively. These studies implicate CYP4A1 as a major 20-HETE synthesizing activity in the rat kidney and further document the feasibility of using antisense ODNs to specifically inhibit 20-HETE synthesis and thereby investigate its role in the regulation of renal function and blood pressure.

scholarly journals Induction of renal arachidonate cytochrome P-450 epoxygenase after uninephrectomy: counterregulation of hyperfiltration.

1993 ◽  
Vol 3 (8) ◽  
pp. 1496-1500
Author(s):  
K Takahashi ◽  
R C Harris ◽  
J H Capdevila ◽  
A Karara ◽  
K Makita ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Enzymatic Activity ◽  
Renal Mass ◽  
Rat Kidney ◽  
Unilateral Nephrectomy ◽  
Arachidonate Metabolism ◽  
Baseline Values ◽  
Cytochrome P 450 ◽  
Stimulation Of

After unilateral nephrectomy (UNx) in the rat, cytochrome P-450 (cP-450)-linked arachidonate enzymatic activity was markedly and specifically induced in microsomal fractions from the remaining kidney. The enzymatic activity reached 200% at 1 wk and 285% at 2 wk post-UNx as compared with non-UNx controls. Mean baseline values for GFR and RPF rate in the remaining kidney 2 wk after UNx were 1.56 +/- 0.10 and 6.47 +/- 0.35 mL/min, respectively. In these rats, the administration of ketoconazole, a cP-450 inhibitor, led to 75% inhibition of renal cP-450 arachidonate metabolism and was associated with acute augmentations in both GFR and RPF to 1.82 +/- 0.18 (P < 0.05 versus baseline) and 7.54 +/- 0.37 mL/min (P < 0.05 versus baseline), respectively. Because vasoconstrictor arachidonate epoxygenase products are endogenously generated in the rat kidney, these findings suggest that the stimulation of renal cP-450-mediated oxygenation of arachidonic acid may subserve an important counterregulatory function in mitigating the renal hyperperfusion and hyperfiltration that follow reductions in renal mass.

Endothelium-derived hyperpolarizing factor in coronary microcirculation: responses to arachidonic acid

2001 ◽  
Vol 281 (4) ◽  
pp. H1553-H1560 ◽  
Author(s):  
Christine L. Oltman ◽  
Neal L. Kane ◽  
Jonathon L. Fudge ◽  
Neal L. Weintraub ◽  
Kevin C. Dellsperger
Keyword(s):  
Arachidonic Acid ◽  
Beating Heart ◽  
Coronary Microcirculation ◽  
Cyclooxygenase Inhibitors ◽  
Resistance Vessels ◽  
Heart Preparation ◽  
Oxide Synthase ◽  
Cytochrome P 450

In coronary resistance vessels, endothelium-derived hyperpolarizing factor (EDHF) plays an important role in endothelium-dependent vasodilation. EDHF has been proposed to be formed through cytochrome P-450 monooxygenase metabolism of arachidonic acid (AA). Our hypothesis was that AA-induced coronary microvascular dilation is mediated in part through a cytochrome P-450 pathway. The canine coronary microcirculation was studied in vivo (beating heart preparation) and in vitro (isolated microvessels). Nitric oxide synthase (NOS) ( N ω-nitro-l-arginine, 100 μM) and cyclooxygenase (indomethacin, 10 μM) or cytochrome P-450 (clotrimazole, 2 μM) inhibition did not alter AA-induced dilation. However, when a Ca2+-activated K+ channel channel or cytochrome P-450 antagonist was used in combination with NOS and cyclooxygenase inhibitors, AA-induced dilation was attenuated. We also show a negative feedback by NO on NOS-cyclooxygenase-resistant AA-induced dilation. We conclude that AA-induced dilation is attenuated by cytochrome P-450 inhibitors, but only when combined with inhibitors of cyclooxygenase and NOS. Therefore, redundant pathways appear to mediate the AA response in the canine coronary microcirculation.

Cytochrome P-450 pathway in acetylcholine-induced canine coronary microvascular vasodilation in vivo

1998 ◽  
Vol 274 (1) ◽  
pp. H283-H289 ◽  
Author(s):  
Mark D. Widmann ◽  
Neal L. Weintraub ◽  
Jonathan L. Fudge ◽  
Leonard A. Brooks ◽  
Kevin C. Dellsperger
Keyword(s):  
Nitric Oxide ◽  
Arachidonic Acid ◽  
Sodium Nitroprusside ◽  
No Synthase ◽  
Coronary Microcirculation ◽  
Coronary Resistance ◽  
Resistance Vessels ◽  
Cytochrome P 450

In the canine coronary microcirculation, acetylcholine (ACh)-induced vasodilation of large (≥100 μm) epicardial arterioles (LgA), but not small (<100 μm) epicardial arterioles (SmA), is blocked by nitric oxide (NO) synthase inhibitors in vivo. We hypothesized that the ACh-induced vasodilation of SmA is mediated by a cytochrome P-450 metabolite of arachidonic acid (AA). Epicardial coronary microvascular diameters in dogs were measured at baseline and after treatment with topically applied ACh (1, 10, and 100 μM), AA (1, 5, and 10 μM), or sodium nitroprusside (SNP; 10–100 μM). Coronary microvascular diameters were compared among control dogs ( group OO); dogs pretreated with N ω-nitro-l-arginine (l-NNA; 70 μM topically) ( group NO); dogs pretreated withl-NNA plus clotrimazole (Clo; 1.6 μM topically) or 17-octadecynoic acid (ODYA; 2 μM topically), cytochrome P-450 monooxygenase inhibitors ( groups NC and NY, respectively); dogs pretreated with Clo alone ( group OC); and dogs pretreated with l-NNA plus Clo with AA as the agonist ( group AA). ACh-induced vasodilation of LgA was abolished byl-NNA alone, whereas in SmA,l-NNA was without effect. Clo alone did not inhibit ACh-induced dilation in either SmA or LgA. However, the combinations ofl-NNA plus either Clo or ODYA abolished ACh- and AA-induced dilation of SmA (100 μM ACh: NC, 3 ± 5%; NY, 8 ± 2%; 10 μM AA: 6 ± 3%) but did not affect responses to SNP. These results suggest that the ACh-induced vasodilation of SmA is mediated in part by cytochrome P-450 metabolites of AA and provide the first evidence that the cytochrome P-450 pathway contributes to the regulation of coronary resistance vessels in vivo.

Na(+)-K+(NH4+)-2Cl- cotransport in medullary thick ascending limb: control by PKA, PKC, and 20-HETE

1996 ◽  
Vol 271 (2) ◽  
pp. C455-C463 ◽  
Author(s):  
H. Amlal ◽  
C. Legoff ◽  
C. Vernimmen ◽  
M. Paillard ◽  
M. Bichara
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase ◽  
Rat Kidney ◽  
Thick Ascending Limb ◽  
Dependent Protein Kinase ◽  
Cyclic Monophosphate ◽  
Medullary Thick Ascending Limb ◽  
Kinase C ◽  
Dependent Protein ◽  
Cytochrome P 450

Cell pH was monitored in suspensions of medullary thick ascending limbs (MTALs) of rat kidney to determine possible effects of various transduction pathways on apical Na(+)-K+ (NH4+)-2Cl- cotransport, the activity of which was measured as the bumetanide-sensitive component of cell acidification caused by abrupt exposure to 4 mM NH4Cl. 8-Bromoadenosine 3',5'-cyclic monophosphate stimulated cotransport activity through activation of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA), since the cAMP effect was abolished by N-[2-(p- bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89); stimulation by cAMP (P < 0.02) was observed even when other Na+, Cl-, and K+ carriers were blocked by ouabain, diphenylamine-2-carboxylate, and barium, which indicates that cotransport was directly affected by PKA. Phorbol 12,13-dibutyrate also stimulated cotransport activity (P < 0.03), which was abolished by protein kinase C (PKC) blockade by staurosporine. In contrast, cotransport activity was reduced (P < 0.001) by arachidonic acid or 20-hydroxyeicosatetraenoic acid (20-HETE), as well as by an ionomycin-induced rise in cytosolic Ca2+ ([Ca2+]i). Inhibition by arachidonic acid or ionomycin was abolished by econazole and SKF-525A that inhibit cytochrome P-450-dependent monoxygenase, which produces 20-HETE from arachidonic acid in the MTAL, and the ionomycin effect was prevented when phospholipase A2 (PLA2) was blocked by 4-bromophenacyl bromide or oleyloxyethyl phosphorylcholine. The results demonstrate that MTAL apical Na(+)-K+(NH4+)-2Cl- cotransport is stimulated by PKA and PKC and inhibited by 20-HETE that may be produced after a rise in [Ca2+]i through PLA2 activation.

scholarly journals Molecular cloning, expression, and enzymatic characterization of the rat kidney cytochrome P-450 arachidonic acid epoxygenase

1993 ◽  
Vol 268 (18) ◽  
pp. 13565-13570
Author(s):  
A. Karara ◽  
K. Makita ◽  
H.R. Jacobson ◽  
J.R. Falck ◽  
F.P. Guengerich ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Molecular Cloning ◽  
Rat Kidney ◽  
Enzymatic Characterization ◽  
Cytochrome P 450

The Fine Structure of Rat Renal Microbodies and Cytoplasmic Bodies Following Perfusion Fixation

1973 ◽  
Vol 31 ◽  
pp. 620-621
Author(s):  
J. M. Barrett ◽  
P. M. Heidger
Keyword(s):  
Fine Structure ◽  
Proximal Tubule ◽  
Rat Kidney ◽  
Renal Proximal Tubule ◽  
Convincing Evidence ◽  
Cytoplasmic Bodies ◽  
Rat Renal Proximal Tubule ◽  
Renal Proximal Tubule Cells ◽  
Perfusion Fixation

Microbodies have received extensive morphological and cytochemical investigation since they were first described by Rhodin in 1954. To our knowledge, however, all investigations of microbodies and cytoplasmic bodies of rat renal proximal tubule cells have employed immersion fixation. Tisher, et al. have shown convincing evidence of fine structural alteration of microbodies in rhesus monkey kidney following immersion fixation; these alterations were not encountered when in vivo intravascular perfusion was employed. In view of these studies, and the fact that techniques for perfusion fixation have been established specifically for the rat kidney by Maunsbach, it seemed desirable to employ perfusion fixation to study the fine structure and distribution of microbodies and cytoplasmic bodies within the rat renal proximal tubule.

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