Cerebral arteries can generate 5- and 15-hydroxyeicosatetraenoic acid from arachidonic acid

1990 ◽  
Vol 68 (7) ◽  
pp. 807-813 ◽  
Author(s):  
Richard Schulz ◽  
Sonia Jancar ◽  
David A. Cook
Keyword(s):  
Arachidonic Acid ◽  
Cerebral Artery ◽  
High Performance ◽  
Contractile Activity ◽  
Cerebral Arteries ◽  
Hydroxyeicosatetraenoic Acid ◽  
Lipoxygenase Pathway ◽  
Product Profile ◽  
Dose Dependent Increase ◽  
Dose Dependent

Products of the lipoxygenase pathway have been implicated in the development of the cerebrovascular spasm that arises after subarachnoid hemorrhage. In particular the hydroperoxyeicosatetranenoic acids (HPETEs), which are unstable and break down rapidly to the corresponding 5-hydroxy acids (HETEs), are vasoconstrictor agents that mimic some aspects of cerebrovascular spasm. It is not, however, well established whether segments of cerebral artery can manufacture these products. We have studied the lipoxygenase product profile of cerebral arteries stimulated with arachidonic acid. Rings of bovine cerebral arteries were incubated in Krebs solution containing arachidonic acid. The lipoxygenase products were studied using high performance liquid chromatography. The largest peaks had the retention times of 5- and 15-HETEs, and the identity of these peaks was confirmed using specific radioimmunoassays. Stimulation with arachidonic acid resulted in a time- and dose-dependent increase in the formation of both HETEs, with 15-HETE being most abundant. The release of both HETEs was markedly reduced in the presence of AA-861, an inhibitor of lipoxygenase, but not with the cyclooxygenase inhibitor indomethacin. These data are thus consistent with our previous suggestion that the contractile activity of arachidonic acid in cerebral arteries arises, at least in part, from HPETE formation and with a possible role for these compounds in cerebral vasospasm.Key words: arachidonic acid, cerebral artery, hydroxyeicosatetraenoic acid, lipoxygenase.

scholarly journals Metabolism of arachidonic acid in nervous system of marine mollusk Aplysia californica

1991 ◽  
Vol 260 (5) ◽  
pp. R844-R848 ◽  
Author(s):  
D. Piomelli
Keyword(s):  
Arachidonic Acid ◽  
Intracellular Signaling ◽  
High Performance ◽  
Aplysia Californica ◽  
Gas Chromatography Mass Spectrometry ◽  
Neural Cells ◽  
Lipoxygenase Pathway ◽  
Marine Mollusk ◽  
Fmrf Amide ◽  
12 Lipoxygenase

Studies of the marine mollusk Aplysia californica indicate that products of the 12-lipoxygenase pathway may be involved in neuronal intracellular signaling. The nervous tissue of Aplysia has a 12-lipoxygenase activity that converts both exogenous and endogenous arachidonic acid to an array of products, which include 12-hydroperoxyeicosatetraenoic acid (12-HPETE) and its metabolites hepoxilin A3, hepoxilin B3, 12-ketoeicosatetraenoic acid, and 12-oxododecatrienoic acid. These eicosanoids were identified using a combination of high-performance liquid chromatography, ultraviolet spectrometry and gas chromatography-mass spectrometry. Generation of 12-lipoxygenase products was stimulated by application of the neurotransmitters, histamine and FMRF-amide, or by stimulation of identified neural cells. In electrophysiological studies of identified L14 and sensory neurons it was found that 12-HPETE and its metabolic products exert physiological actions that resemble those of histamine and FMRF-amide. These results suggest that products of 12-HPETE metabolism may act as second messengers in Aplysia neurons.

Inhibition Of Platelet Aggregation, Malonyldialdehyde And Thromboxane Formation By Hydroperoxides Of Arachidonic Acid

1981 ◽  
Author(s):  
D Aharonv ◽  
J B Smith ◽  
M J Silver
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Lipoxygenase Pathway ◽  
Dose Dependent Fashion ◽  
Induced Aggregation ◽  
Layer Chromatography ◽  
Dose Dependent ◽  
Thromboxane Formation

The arachidonate hydroperoxides 12-HPETE and 15-HPETE were biosynthesized from arachidonic acid using partially purified human platelet lipoxygenase or soybean lipoxidase respectively, and isolated by thin layer chromatography. Both compounds inhibited the arachidonic acid- induced aggregation of washed human platelets, suspended in calcium-free Krebs Henseleit solution, in a dose dependent fashion at concentrations between 1 and 50 uM. No inhibition was seen with up to 100 uM of these hydroperoxides when platelet -rich plasma was used. 12-HPETE (in micromolar concentrations) inhibited the formation of both thromboxane B2 (radioimmunoassay) and malonyldialdehyde (spectrophotometrie assay) when washed platelets were incubated with arachidonic acid. The 12-hydroxide, 12-HETE also inhibited platelet aggregation and thromboxane formation, but was less potent than 12-HPETE. We suggest that arachidonate hydroperoxide generated in platelets via the lipoxygenase pathway modulates platelet aggregation induced by arachidonic acid by inhibiting thromboxane formation.

Effect of protein kinase C activating agents on respiratory glycoconjugate release from feline airways

1991 ◽  
Vol 261 (6) ◽  
pp. L415-L423 ◽  
Author(s):  
R. D. Rieves ◽  
J. D. Lundgren ◽  
C. Logun ◽  
T. Wu ◽  
J. H. Shelhamer
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Acid Metabolism ◽  
Culture Media ◽  
Experimental Period ◽  
Arachidonic Acid Metabolism ◽  
Lipoxygenase Pathway ◽  
Kinase C ◽  
Dose Dependent

Abnormal regulation of airway glycoprotein secretion may underlie many respiratory diseases. Experimental activation of the protein kinase C (PKC) family of cytosolic enzymes has been shown to induce a secretory response in many tissues. To estimate the effect of PKC activation on airway secretion, alteration in the amount of radiolabeled respiratory glycoconjugate (RGC) released into culture media was determined following feline airway explant exposure to PKC activating agents. Exposure to two known activators of PKC, phorbol 12-myristate 13-acetate (PMA) and mezerein (MEZ), resulted in profound increases in respiratory glycoconjugate release over a seven day experimental period. The response evolved over several hours and was dose dependent. Maximal RGC release, 90% above control, occurred 2 days after exposure to either PMA or MEZ. Pharmacological inhibition of the PKC effect using two PKC inhibitors, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine and sphingosine, resulted in dose-dependent antagonism of the maximal PMA (10(-7) M)-stimulated RGC release, suggesting altered PKC activity was responsible for augmenting RGC release. Since altered arachidonic acid metabolism has been implicated in mediating some PKC effects, eicosanoids were assayed in airway explant supernatants following PMA exposure. Enhanced release of both cyclooxygenase and lipoxygenase pathway products was detected by radioimmunoassay. Cotreatment of explants with PMA and an inhibitor of oxidative arachidonic acid metabolism, nordihydroguaiaretic acid, blocked RGC release. These data demonstrate prolonged augmentation of respiratory glycoconjugate release from airway explants following exposure to PKC-activating agents.

Regulation of synthesis of prostacyclin and HETEs in human endothelial cells

1989 ◽  
Vol 256 (6) ◽  
pp. C1168-C1175 ◽  
Author(s):  
B. O. Ibe ◽  
J. R. Falck ◽  
A. R. Johnson ◽  
W. B. Campbell
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Caffeic Acid ◽  
Inhibitory Concentration ◽  
Nordihydroguaiaretic Acid ◽  
Hydroxyeicosatetraenoic Acid ◽  
Human Endothelial Cells ◽  
Lipoxygenase Pathway ◽  
Cells In Culture ◽  
Regulation Of Synthesis

Human umbilical endothelial cells in culture synthesize prostacyclin (PGI2), 15-hydroxyeicosatetraenoic acid (15-HETE), and 12-hydroxyeicosatetraenoic acid (12-HETE). The synthesis of these eicosanoids was measured by specific radioimmunoassays after stimulation by arachidonic acid, A23187, bradykinin, melittin, or histamine. Under all conditions, the synthesis of PGI2 paralleled and exceeded the synthesis of 15-HETE and 12-HETE. Indomethacin inhibited arachidonic acid-stimulated PGI2 and 15-HETE synthesis but enhanced 12-HETE synthesis. Meclofenamate gave similar qualitative results. Drugs that act as inhibitors of lipoxygenase in some tissues, such as nordihydroguaiaretic acid (NDGA), caffeic acid, esculin, diethylcarbamazine, quercetin, and 5,8,11,14-eicosatetrayenoic acid (ETYA) were nonspecific in their inhibition of PGI2, 12-HETE, and 15-HETE synthesis. For example, NDGA inhibited arachidonic acid-stimulated release with a 50% inhibitory concentration (IC50) of 0.39 microM for PGI2, 0.25 microM for 15-HETE, and 0.10 microM for 12-HETE. These results show that endothelial cells metabolize both endogenous and exogenous arachidonic acid to PGI2, 15-HETE, and 12-HETE. These data also suggest, based on results with inhibitors, that PGI2 and 15-HETE are products of cyclooxygenase, whereas 12-HETE is produced via a different enzymatic pathway, most likely a lipoxygenase pathway.

Effect of pentobarbital on the reactivity of isolated human cerebral arteries

1981 ◽  
Vol 54 (4) ◽  
pp. 521-524 ◽  
Author(s):  
Jesús Marín ◽  
Ramiro D. Lobato ◽  
Mercedes L. Rico ◽  
Mercedes Salaices ◽  
Julio Benitez
Keyword(s):  
Contractile Activity ◽  
Cerebral Arteries ◽  
Cerebrovascular Reactivity ◽  
Mechanical Activity ◽  
Dependent Manner ◽  
Content Type ◽  
Basal Tone ◽  
Dose Dependent ◽  
Arterial Tone ◽  
Fine Print

✓ The authors have analyzed the effect of pentobarbital (10−5M to 10−3M) on the contractile activity of isolated human cerebral arteries. Pentobarbital was found to inhibit both the spontaneous mechanical activity and the basal tone of these vessels. Relaxation induced by this drug was dose-dependent, and was more marked when the arterial tone was previously increased with noradrenalin, potassium chloride, or 5-hydroxytryptamine. In addition, pentobarbital inhibits, in a dose-dependent manner, the contractions elicited by these vasoconstrictor agents. The present findings indicate that barbiturates decrease cerebrovascular reactivity, and disagree with the hypothesis that these drugs reduce raised intracranial pressure by means of exerting a direct constrictive effect on the cerebral arteries.

Angiotensin-induced relaxation in isolated dog renal and cerebral arteries

1981 ◽  
Vol 240 (2) ◽  
pp. H247-H254 ◽  
Author(s):  
N. Toda ◽  
M. Miyazaki
Keyword(s):  
Arachidonic Acid ◽  
Angiotensin Ii ◽  
Cerebral Arteries ◽  
Dependent Manner ◽  
Rat Stomach ◽  
Middle Cerebral Arteries ◽  
Dose Dependent ◽  
Relaxing Effect ◽  
Indomethacin Treatment ◽  
Stimulation Of

Helically cut strips of dog renal and cerebral (basilar and middle cerebral) arteries contracted with prostaglandin (PG) F2 alpha relaxed in response to angiotensin II (AII; 10(-9) to 10(-7) M) in a dose-dependent manner. In renal arterial strips, the relaxation was preceded by a transient contraction. Both the relaxation and the contraction induced by AII were suppressed by [Sar1,Ala8]AII or [Sar1,Ile8]AII. Treatment with propranolol, atropine, hexamethonium, cocaine, aminophylline, cimetidine, or ouabain failed to alter the relaxing effect of AII. The peptide-induced relaxation was reversed to a contraction by aspirin or indomethacin. Treatment with tranylcypromine or 15-hydroperoxy arachidonic acid suppressed the relaxation induced by AII in renal and cerebral arteries but did not alter relaxations induced by PGI2 or K+ (5 mM). In experiments with superfused dog renal and coronary arteries and rat stomach strips, the renal arteries in response to AII released a prostaglandin like substance; the release was suppressed by [Sar1,Ala8]AII or indomethacin. It appears that the relaxation of isolated dog renal and cerebral arteries induced by AII is mediated by the release of PGI2, which is associated with stimulation of AII receptors.

Developmental changes in alpha 1-adrenergic receptors, IP3 responses, and NE-induced contraction in cerebral arteries

1996 ◽  
Vol 271 (6) ◽  
pp. H2313-H2319 ◽  
Author(s):  
L. D. Longo ◽  
N. Ueno ◽  
Y. Zhao ◽  
W. J. Pearce ◽  
L. Zhang
Keyword(s):  
Cerebral Artery ◽  
Adrenergic Receptors ◽  
Cerebral Arteries ◽  
Developmental Changes ◽  
Developmental Age ◽  
Age Dependent ◽  
Density Values ◽  
The Common ◽  
Pharmacomechanical Coupling ◽  
Dose Dependent

Cerebral arteries show significant developmental and artery-specific changes in noradrenergic-mediated contraction. To test the hypothesis that these changes result from differences in the density of alpha 1-adrenergic receptors (alpha 1-ARs) and/or norepinephrine (NE)-induced inositol 1,4,5-trisphosphate [Ins(1,4,5)P3,IP3] synthesis, we quantified these variables and the NE-induced contraction in the common carotid artery (Com) and main branch cerebral arteries (MBC) from term fetal (approximately 140 gestational day) and newborn (2- to 5-day) sheep and compared them with adult values. In fetal and newborn Com, maximal contractions to NE (percent K+ maximum response) were 132 +/- 14 and 118 +/- 9%, respectively (adult = 92 +/- 7%). For fetal and newborn middle cerebral artery, these values were 34 +/- 10 and 43 +/- 7%, respectively (adult = 24 +/- 7%). alpha 1-AR density values in Com of fetal and newborn sheep were 113 +/- 18 and 106 +/- 4 fmol/mg protein, respectively (adult = 54 +/- 3 fmol/mg protein). For the MBC, density values were 47 +/- 2 and 24 +/- 3 fmol/mg protein, respectively (adult = 23 +/- 3 fmol/protein). In term fetal and newborn MBC, NE produced dose-dependent increases in Ins(1,4,5)P3, the maximal increases above basal values being 245 +/- 40 and 189 +/- 16%, respectively (adult = 254 +/- 35%). Neither fetus nor newborn Com showed significant Ins(1,4,5)P3 responses to NE. We concluded that in fetal and newborn Com and MBC, alpha 1-AR density and NE-induced Ins(1,4,5)P3 response varied as a function of developmental age and specific vessel. However, these variations did not correlate with NE-induced maximum contraction. Thus we reject the hypothesis that age-dependent and vessel-specific differences of cerebral artery adrenergic-mediated contraction are a function of alpha 1-AR density or Ins(1,4,5)P3 response. Rather, the differences would appear to result from other factors such as non-Ins(1,4,5)P3-mediated calcium activation and/or sensitivity to Ins(1,4,5)P3. The studies also suggest considerable potential for maturational modulation of pharmacomechanical coupling and homeostatic regulation of cerebrovascular tone.

Serotonin inhibits the peptide FMRFamide response through a cyclic AMP-independent pathway in Aplysia

1991 ◽  
Vol 66 (6) ◽  
pp. 1847-1857
Author(s):  
R. Y. Shi ◽  
F. Belardetti
Keyword(s):  
Arachidonic Acid ◽  
Outward Current ◽  
Inhibitory Effect ◽  
Resting Potential ◽  
Slow Inward Current ◽  
K Channel ◽  
Current Response ◽  
Lipoxygenase Pathway ◽  
Inward Current ◽  
Dose Dependent

1. The S-K+ conductance was isolated by voltage-clamping near the resting potential pleural mechanosensory neurons of Aplysia in culture. This background conductance is modulated in opposite directions by two distinct, transmitter-controlled second-messenger cascades: it is enhanced by the peptide FMRFamide through the 12-lipoxygenase pathway of arachidonic acid, and it is decreased by serotonin (5-HT) through adenosine 3',5'-cyclic monophosphate (cAMP)-dependent phosphorylation. 2. The dose-dependent activating effect of FMRFamide (0.01-500 microM) on the S-K+ conductance was measured in the presence and the absence either of 1-100 microM 8-bromo-cAMP (8b-cAMP, a membrane-permeable and hydrolysis-resistant analogue of cAMP), or of 0.01-0.1 microM 5-HT. 3. When 8b-cAMP was applied, it produced a slow inward current response due to closure of the S-K+ conductance. This response was antagonized by FMRFamide in a dose-dependent mode. Application of 100 microM FMRFamide, in the presence of 1-10 microM 8b-cAMP, produced an outward current response larger than the control FMRFa response and equal to the sum of the responses to FMRFamide alone and to 8b-cAMP alone. Similarly, at 500 microM, FMRFamide completely antagonized the closing action of maximal 8b-cAMP levels (100 microM). This observation confirms previous work that indicated that FMRFamide can reopen S-K+ channels closed by FMRFamide. 4. In contrast, in the presence of moderate concentrations of 5-HT (0.01 microM), which produce a slow inward current due to the closing of the S-K+ conductance, FMRFamide elicited a response that only partially antagonized this 5-HT action. Under maximal 5-HT concentrations (0.1 microM), the 5-HT response was not antagonized by any FMRFamide concentration: instead, the FMRFamide response was smaller than the control response without 5-HT. This experiment suggests that 5-HT, with an action independent from cAMP, inhibits the effect of FMRFamide on the S-K+ channel. 5. The dose-dependent inhibitory effect of 5-HT (0.001-10 microM) on the S-K+ conductance was measured in the presence and the absence either of FMRFamide (1-50 microM), which stimulates the release and metabolism of arachidonic acid in Aplysia sensory neurons or of arachidonic acid (25 microM). 6. Under these conditions, supramaximal concentrations of 5-HT could not completely suppress the slow outward current evoked by FMRFamide or by arachidonic acid, indicating that a component of the arachidonic-mediated response to FMRFamide is resistant to actions that maximally increase the S-K+ channel phosphorylation.(ABSTRACT TRUNCATED AT 400 WORDS)

Endothelial Cells Produce a Lipoxygenase Derived Chemo-Repellent which Influences Platelet/Endothelial Cell Interactions – Effect of Aspirin and Salicylate

1985 ◽  
Vol 53 (03) ◽  
pp. 306-311 ◽  
Author(s):  
M R Buchanan ◽  
R W Butt ◽  
Z Magas ◽  
J Van Ryn ◽  
J Hirsh ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Endothelial Cell ◽  
High Performance ◽  
Platelet Adhesion ◽  
Cell Interactions ◽  
Lipoxygenase Pathway ◽  
Associated Production ◽  
Pathway Inhibition ◽  
Layer Chromatography

SummaryWe performed experiments to determine whether endothelial cells synthesize phospholipid metabolites via the lipoxygenase pathway and whether these metabolites influence platelet/vessel wall interactions. Monolayers of cultured human endothelial cells were incubated with 14C-arachidonic acid and their cyclo-oxygenase and lipoxygenase metabolites were extracted and identified by radioimmunoassay, thin layer chromatography and high performance liquid chromatography. We found that in addition to the membrane-associated production of PGI2, endothelial cells synthesized a cytosol-associated metabolite, LOX, which was presumably derived through the lipoxygenase pathway. Inhibition of LOX was associated with an increase in PGI2 production and inhibition of PGI2 with an increase in LOX production. Under either condition, platelet adhesion to cultured endothelial cells was significantly decreased. In contrast, when both PGI2 and LOX production were inhibited, platelet adhesion to endothelial cells was enhanced. Furthermore, when LOX was bound to a thrombogenic surface, platelet adhesion was significantly decreased whereas when arachidonic acid or 12-HETE was bound to the surface, platelet adhesion was increased. We conclude that endothelial cells produce not only a cyclo-oxygenase metabolite, but also a lipoxygenase metabolite, both of which influence platelet/endothelial cell interactions.

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