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Effects of sub-chronic, in vivo administration of sigma-1 receptor ligands on platelet and aortic arachidonate cascade in streptozotocin-induced diabetic rats. PLoS One 2022; 17:e0265854. [DOI: 10.1371/journal.pone.0265854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 09/28/2022] [Indexed: 11/18/2022] Open
Abstract
Background
Diabetes mellitus is a chronic metabolic disorder which induces endothelial dysfunction and platelet activation. Eicosanoids produced from arachidonic acid regulate cellular and vascular functions. Sigma-1 receptors (S1R) are expressed in platelets and endothelial cells and S1R expression is protective in diabetes.
Objectives
Our aim was to examine the influence of sub-chronic, in vivo administered S1R ligands PRE-084, (S)-L1 (a new compound) and NE-100 on the ex vivo arachidonic acid metabolism of platelets and aorta in streptozotocin-induced diabetic rats.
Methods
The serum level of the S1R ligands was detected by LC-MS/MS before the ex vivo analysis. Sigma-1 receptor and cyclooxygenase gene expression in platelets were determined by RT-qPCR. The eicosanoid synthesis was examined with a radiolabelled arachidonic acid substrate and ELISA.
Results
One month after the onset of STZ-induced diabetes, in vehicle-treated, diabetic rat platelet TxB2 and aortic 6-k-PGF1α production dropped. Sub-chronic in vivo treatment of STZ-induced diabetes in rats for one week with PRE-084 enhanced vasoconstrictor and platelet aggregator and reduced vasodilator and anti-aggregator cyclooxygenase product formation. (S)-L1 reduced the synthesis of vasodilator and anti-aggregator cyclooxygenase metabolites and promoted the recovery of physiological platelet function in diabetic rats. The S1R antagonist NE-100 produced no significant changes in platelet arachidonic acid metabolism. (S)-L1 decreased the synthesis of vasoconstrictor and platelet aggregator cyclooxygenase metabolites, whereas NE-100 increased the quantity of aortic vasodilator and anti-aggregator cyclooxygenase products and promoted the recovery of diabetic endothelial dysfunction in the aorta. The novel S1R ligand, (S)-L1 had similar effects on eicosanoid synthesis in platelets as the agonist PRE-084 and in aortas as the antagonist NE-100.
Conclusions
S1R ligands regulate cellular functions and local blood circulation by influencing arachidonic acid metabolism. In diabetes mellitus, the cell-specific effects of S1R ligands have a compensatory role and aid in restoring physiological balance between the platelet and vessel.
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Váczi S, Barna L, Laczi K, Tömösi F, Rákhely G, Penke B, Fülöp L, Bogár F, Janáky T, Deli MA, Mezei Z. Effects of sub-chronic, in vivo administration of sigma non-opioid intracellular receptor 1 ligands on platelet and aortic arachidonate cascade in rats. Eur J Pharmacol 2022; 925:174983. [PMID: 35487254 DOI: 10.1016/j.ejphar.2022.174983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 12/25/2022]
Abstract
Platelets regulate cell-cell interactions and local circulation through eicosanoids from arachidonic acid. Sigma non-opioid intracellular receptor 1 (sigma-1 receptor) expressed in platelets and endothelial cells can regulate intracellular signalization. Our aim was to examine the influence of sub-chronic, in vivo-administered sigma-1 receptor ligands 2-morpholin-4-ylethyl 1-phenylcyclohexane-1-carboxylate (PRE-084); N-benzyl-2-[(1S)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-1-yl]ethan-1-amine; dihydrochloride, a new compound ((S)-L1); and N-[2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethyl]-N-propylpropan-1-amine (NE-100) on the ex vivo arachidonic acid metabolism of the platelets and aorta of male rats. The serum level of sigma-1 receptor ligands was determined by liquid chromatography-mass spectrometry. Sigma-1 receptor and cyclooxygenase gene expression in the platelets were determined by a reverse transcription-coupled quantitative polymerase chain reaction. The eicosanoid synthesis was examined using a radiolabeled arachidonic acid substrate and enzyme-linked immunosorbent assay. We confirmed the absorption of sigma-1 receptor ligands and confirmed that the ligands were not present during the ex vivo studies, so their acute effect could be excluded. We detected no changes in either sigma-1 receptor or cyclooxygenase mRNA levels in the platelets. Nevertheless, (S)-L1 and NE-100 increased the quantity of cyclooxygenases there. Both platelet and aortic eicosanoid synthesis was modified by the ligands, although in different ways. The effect of the new sigma-1 receptor ligand, (S)-L1, was similar to that of PRE-084 in most of the parameters studied but was found to be more potent. Our results suggest that sigma-1 receptor ligands may act at multiple points in arachidonic acid metabolism and play an important role in the control of the microcirculation by modulating the eicosanoid synthesis of the platelets and vessels.
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Affiliation(s)
- Sándor Váczi
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary; Doctoral School of Theoretical Medicine, University of Szeged, H-6725, Szeged, Hungary.
| | - Lilla Barna
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), H-6725, Szeged, Hungary; Doctoral School of Biology, University of Szeged, H-6725, Szeged, Hungary.
| | - Krisztián Laczi
- Department of Biotechnology, University of Szeged, H-6725, Szeged, Hungary.
| | - Ferenc Tömösi
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary.
| | - Gábor Rákhely
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), H-6725, Szeged, Hungary; Department of Biotechnology, University of Szeged, H-6725, Szeged, Hungary.
| | - Botond Penke
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary.
| | - Lívia Fülöp
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary.
| | - Ferenc Bogár
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary; MTA-SZTE Biomimetic Systems Research Group, Eötvös Loránd Research Network (ELKH), H-6725, Szeged, Hungary.
| | - Tamás Janáky
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary.
| | - Mária A Deli
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), H-6725, Szeged, Hungary.
| | - Zsófia Mezei
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary; Department of Physiology, Albert Szent-Györgyi Medical School, University of Szeged, H-6725, Szeged, Hungary.
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Tuomisto K, Palmu J, Long T, Watrous JD, Mercader K, Lagerborg KA, Andres A, Salmi M, Jalkanen S, Vasan RS, Inouye M, Havulinna AS, Tuomilehto J, Jousilahti P, Niiranen TJ, Cheng S, Jain M, Salomaa V. A plasma metabolite score of three eicosanoids predicts incident type 2 diabetes: a prospective study in three independent cohorts. BMJ Open Diabetes Res Care 2022; 10:10/2/e002519. [PMID: 35361620 PMCID: PMC8971778 DOI: 10.1136/bmjdrc-2021-002519] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 01/18/2022] [Indexed: 01/02/2023] Open
Abstract
INTRODUCTION Peptide markers of inflammation have been associated with the development of type 2 diabetes. The role of upstream, lipid-derived mediators of inflammation such as eicosanoids, remains less clear. The aim of this study was to examine whether eicosanoids are associated with incident type 2 diabetes. RESEARCH DESIGN & METHODS In the FINRISK (Finnish Cardiovascular Risk Study) 2002 study, a population-based sample of Finnish men and women aged 25-74 years, we used directed, non-targeted liquid chromatography-mass spectrometry to identify 545 eicosanoids and related oxylipins in the participants' plasma samples (n=8292). We used multivariable-adjusted Cox regression to examine associations between eicosanoids and incident type 2 diabetes. The significant independent findings were replicated in the Framingham Heart Study (FHS, n=2886) and DIetary, Lifestyle and Genetic determinants of Obesity and Metabolic syndrome (DILGOM) 2007 (n=3905). Together, these three cohorts had 1070 cases of incident type 2 diabetes. RESULTS In the FINRISK 2002 cohort, 76 eicosanoids were associated individually with incident type 2 diabetes. We identified three eicosanoids independently associated with incident type 2 diabetes using stepwise Cox regression with forward selection and a Bonferroni-corrected inclusion threshold. A three-eicosanoid risk score produced an HR of 1.56 (95% CI 1.41 to 1.72) per 1 SD increment for risk of incident diabetes. The HR for comparing the top quartile with the lowest was 2.80 (95% CI 2.53 to 3.07). In the replication analyses, the three-eicosanoid risk score was significant in FHS (HR 1.24 (95% CI 1.10 to 1.39, p<0.001)) and directionally consistent in DILGOM (HR 1.12 (95% CI 0.99 to 1.27, p=0.07)). Meta-analysis of the three cohorts yielded a pooled HR of 1.31 (95% CI 1.05 to 1.56). CONCLUSIONS Plasma eicosanoid profiles predict incident type 2 diabetes and the clearest signals replicate in three independent cohorts. Our findings give new information on the biology underlying type 2 diabetes and suggest opportunities for early identification of people at risk.
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Affiliation(s)
- Karolina Tuomisto
- Department of Public Health, University of Helsinki, Helsinki, Finland
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Joonatan Palmu
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
- Department of Internal Medicine, University of Turku, Turku, Finland
| | - Tao Long
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Jeramie D Watrous
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Kysha Mercader
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Kim A Lagerborg
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Allen Andres
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Marko Salmi
- MediCity, InFLAMES Flagship, and Institute of Biomedicine, University of Turku, Turku, Finland
| | - Sirpa Jalkanen
- MediCity, InFLAMES Flagship, and Institute of Biomedicine, University of Turku, Turku, Finland
| | - Ramachandran S Vasan
- Boston University's and National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, Massachusetts, USA
- Sections of Preventive Medicine and Epidemiology, and Cardiovascular Medicine, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Michael Inouye
- Cambridge Baker Systems Genomics Initiative, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- Cambridge Baker Systems Genomics Initiative, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Aki S Havulinna
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
- University of Helsinki Institute for Molecular Medicine Finland, Helsinki, Finland
| | - Jaakko Tuomilehto
- Department of Public Health, University of Helsinki, Helsinki, Finland
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Pekka Jousilahti
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Teemu J Niiranen
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
- Department of Internal Medicine, University of Turku, Turku, Finland
| | - Susan Cheng
- Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Mohit Jain
- Departments of Medicine and Pharmacology, University of California San Diego, La Jolla, California, USA
| | - Veikko Salomaa
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
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Váczi S, Barna L, Harazin A, Mészáros M, Porkoláb G, Zvara Á, Ónody R, Földesi I, Veszelka S, Penke B, Fülöp L, Deli MA, Mezei Z. S1R agonist modulates rat platelet eicosanoid synthesis and aggregation. Platelets 2021; 33:709-718. [PMID: 34697991 DOI: 10.1080/09537104.2021.1981843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Sigma-1 receptor (S1R) is detected in different cell types and can regulate intracellular signaling pathways. S1R plays a role in the pathomechanism of diseases and the regulation of neurotransmitters. Fluvoxamine can bind to S1R and reduce the serotonin uptake of neurons and platelets. We therefore hypothesized that platelets express S1R, which can modify platelet function. The expression of the SIGMAR1 gene in rat platelets was examined with a reverse transcription polymerase chain reaction and a quantitative polymerase chain reaction. The receptor was also visualized by immunostaining and confocal laser scanning microscopy. The effect of S1R agonist PRE-084 on the eicosanoid synthesis of isolated rat platelets and ADP- and AA-induced platelet aggregation was examined. S1R was detected in rat platelets both at gene and protein levels. Pretreatment with PRE-084 of resting platelets induced elevation of eicosanoid synthesis. The rate of elevation in thromboxane B2 and prostaglandin D2 synthesis was similar, but the production of prostaglandin E2 was higher. The concentration-response curve showed a sigmoidal form. The most effective concentration of the agonist was 2 µM. PRE-084 increased the quantity of cyclooxygenase-1 as detected by ELISA. PRE-084 also elevated the ADP- and AA-induced platelet aggregation. S1R of platelets might regulate physiological or pathological functions.
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Affiliation(s)
- Sándor Váczi
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.,Doctoral School of Theoretical Medicine, University of Szeged, Szeged, Hungary.,Gedeon Richter Talentum Foundation Scholarship, Budapest, Hungary
| | - L Barna
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - A Harazin
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - M Mészáros
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - G Porkoláb
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Á Zvara
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - R Ónody
- Department of Laboratory Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - I Földesi
- Department of Laboratory Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - S Veszelka
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - B Penke
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - L Fülöp
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - M A Deli
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Z Mezei
- Department of Pathophysiology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.,Department of Physiology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
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5
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Margolin A, Avants SK, Setaro JF, Rinder HM, Grupp L. Cocaine, HIV, and their cardiovascular effects: is there a role for ACE-inhibitor therapy? Drug Alcohol Depend 2000; 61:35-45. [PMID: 11064182 DOI: 10.1016/s0376-8716(00)00124-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cocaine abuse and HIV disease each have potentially adverse effects upon the heart and cardiovascular system which may be exacerbated when these risk factors are combined. The development of a safe and effective agent to treat both cocaine addiction and its cardiovascular sequelae, that is well-tolerated by HIV patients, would thus be of considerable clinical utility. In this article we discuss the rationale for the investigation of angiotensin converting enzyme (ACE) inhibitors, commonly used to treat hypertension, for treatment in cocaine-abusing populations, based on their potential to reduce cocaine use by modulating levels of dopamine and corticotropin releasing factor in the brain, and on their ability to reverse cardiovascular and platelet abnormalities. We present preliminary findings from echocardiographic and platelet activation studies in 16 HIV-positive, cocaine abusing patients, as well as tolerability and efficacy studies of the ACE-inhibitor, fosinopril, for the treatment of cocaine abuse in both HIV-positive (n=6) and HIV-negative (n=5) methadone-maintained cocaine abusers. Findings suggest that HIV-positive cocaine-abusing patients possess abnormalities of diastolic heart function and platelet activation that are potentially reversible with ACE-inhibitor therapy. Findings also suggest that fosinopril is well-tolerated regardless of HIV serostatus, does not appear to cause hypotension, and may possess effectiveness for reducing cocaine use. We conclude that ACE-inhibitor therapy may offer a new pharmacologic approach to the treatment of cocaine abuse and its complications, and that controlled research of this class of agents may be promising.
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Affiliation(s)
- A Margolin
- Department of Psychiatry, Substance Abuse Center, Yale University School of Medicine, 34 Park St., New Haven, CT, 06519, USA.
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6
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Szupera Z, Mezei Z, Kis B, Gecse A, Vécsei L, Telegdy G. The effects of valproate on the arachidonic acid metabolism of rat brain microvessels and of platelets. Eur J Pharmacol 2000; 387:205-10. [PMID: 10650161 DOI: 10.1016/s0014-2999(99)00764-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Long-term administration of the antiepileptic drug valproate can induce hematologic, hepatic and endocrine abnormalities and morphologic alterations in the brain capillaries and glial cells. Valproate elicits bone marrow suppression, reducing the number of red blood cells and platelets, and causes platelet functional abnormalities. Various data suggest that more than one mechanism of valproate-associated toxicity may exist, but the pathomechanism of cell function alterations elicited by valproate has not yet been elucidated. The reported ex vivo experiments were designed to investigate the effects of valproate on the arachidonic acid cascade of rat brain capillaries and platelets. Valproate was administered (300 mg/kg body weight/day) in the drinking water to male Wistar rats for 2 weeks. Isolated platelets and brain microvessels were labelled with [14C]arachidonic acid and the released [14C]eicosanoids were separated by overpressure thin-layer chromatography and determined quantitatively by liquid scintillation counting. Valproate treatment reduced the synthesis of cyclooxygenase and lipoxygenase products in rat platelets. In brain microvessels valproate stimulated the synthesis of lipoxygenase metabolites and attenuated the cyclooxygenase pathway. Modifications of the arachidonate cascade in platelets and brain microvessels may contribute to the cell function alterations caused by valproate.
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Affiliation(s)
- Z Szupera
- Department of Neurology, Albert Szent-Györgyi Medical University, P.O. Box 397, H-6701, Szeged, Hungary.
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Kis B, Mezei Z, Dancsó G, Pataricza J, Gecse A, Papp JG, Telegdy G. Effects of pituitary adenylate cyclase-activating polypeptide on the cyclooxygenase pathway of rat platelets and on platelet aggregation. Prostaglandins Other Lipid Mediat 1999; 58:103-12. [PMID: 10560613 DOI: 10.1016/s0090-6980(99)00039-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Several data suggest that pituitary adenylate cyclase-activating polypeptide (PACAP) is involved in the regulation of local circulation. One possible role of PACAP in the regulation of circulation is that, it may modify the cyclooxygenase pathway of the arachidonate cascade in platelets. Our study was designed to study the effect of PACAP on the cyclooxygenase pathway of rat platelets and on platelet aggregation. PACAP (10(-7) and 10(-6) M) significantly inhibited the cyclooxygenase pathway of platelets, mostly the thromboxane synthesis. Pretreatment with a PACAP receptor antagonist, PACAP(6-38), or with an inhibitor of protein kinase A, H-89, shows that the effects of PACAP on the cyclooxygenase pathway were diminished. In the aggregation studies, PACAP inhibited both the arachidonic acid-induced and the thrombin-induced platelet aggregation. It can be concluded that PACAP inhibits the cyclooxygenase pathway of rat platelets via a specific PACAP receptor-activated, cAMP-dependent pathway, and these effects of PACAP are involved in the inhibition of platelet aggregation.
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Affiliation(s)
- B Kis
- Department of Pathophysiology, Albert Szent-Györgyi Medical University, Szeged, Hungary
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8
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Kis B, Gáspár T, Mezei Z, Gecse A, Telegdy G. Pituitary adenylate cyclase-activating polypeptide inhibits the cyclooxygenase pathway of rat cerebral microvessels. ACTA PHYSIOLOGICA SCANDINAVICA 1999; 167:43-7. [PMID: 10519976 DOI: 10.1046/j.1365-201x.1999.00594.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The presence of nerve endings containing pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) around cerebral microvessels suggests that these peptides have regulatory roles in the cerebral microcirculation. Prostanoids synthesized by the cerebrovascular endothelium have a determining role in the regulation of the brain circulation. In the present study, the effects of PACAP and VIP on the cyclooxygenase pathway of cerebral microvessels were investigated. The isolated microvessels were incubated with 1-14C-arachidonic acid and different concentrations of the peptides. The prostanoids formed were separated by means of overpressure thin-layer chromatography, and were quantitatively determined by liquid scintillation. Higher concentrations (10-7 and 10-6 mol L-1) of PACAP significantly inhibited the activity of the cyclooxygenase pathway, whereas VIP had no significant effect on it. As regards the cyclooxygenase metabolites, the syntheses of thromboxane A2 and prostaglandin D2 were inhibited significantly. PACAP and VIP are known to increase the intracellular cAMP level in the cerebral microvessels and in the present experiments the protein kinase A inhibitor H-89 attenuated the effect of PACAP on prostanoid synthesis. It is concluded that the cyclooxygenase pathway of rat cerebral microvessels is more sensitive to PACAP than to VIP. The inhibitory effect of PACAP on prostanoid synthesis is mediated via a cAMP-dependent pathway. By inhibiting the formation of vasoactive prostanoids, PACAP can decrease the vasoreactivity of the microvessels.
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Affiliation(s)
- B Kis
- Department of Pathophysiology, Albert Szent-Györgyi Medical University, Szeged, Hungary
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9
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Kis B, Szupera Z, Mezei Z, Gecse A, Telegdy G, Vécsei L. Valproate treatment and platelet function: the role of arachidonate metabolites. Epilepsia 1999; 40:307-10. [PMID: 10080510 DOI: 10.1111/j.1528-1157.1999.tb00709.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Valproate (VPA) is an extensively used drug in the therapy of epilepsies. One of the most frequently reported side effects of VPA is hemorrhagic diathesis. Some authors emphasized the decreased platelet count as the basis of VPA-induced hemorrhagic diathesis, but some reports suggested that a significant proportion of patients with normal platelet count may still have an altered platelet function. The mechanism of the VPA-induced platelet dysfunction has not yet been elucidated. A determining element of platelet functions is the arachidonate cascade. Present ex vivo experiments were designed to determine whether a relation exists between the incidence of hemostasis caused by VPA and the effect of this drug on the arachidonate cascade of platelets. METHODS Platelets were isolated from patients receiving long-term VPA treatment (serum level, 36.04+/-16.12 microg/ml; n = 10) or carbamazepine (CBZ) treatment (serum level, 5.24+/-2.67 microg/ml; n = 10) and were labeled with [14C]arachidonic acid. (CBZ-treated patients were chosen as a control group, because CBZ causes blood dyscrasias similar to those elicited by VPA, but there has been no report that CBZ induces a platelet dysfunction.) The 14C-eicosanoids were separated by means of overpressure thin-layer chromatography and determined quantitatively by liquid scintillation. RESULTS Even when the mean plasma concentration of the drug was low, VPA treatment reduced the activity of the arachidonate cascade in platelets. VPA effectively inhibited the cyclooxygenase pathway and the synthesis of the strong platelet aggregator thromboxane A2. CONCLUSIONS Inhibition of the platelet arachidonate cascade may contribute to the platelet-function alterations caused by VPA.
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Affiliation(s)
- B Kis
- Department of Pathophysiology, Albert Szent-Györgyi Medical University, Szeged, Hungary
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10
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Kis B, Szabó CA, Pataricza J, Krizbai IA, Mezei Z, Gecse A, Telegdy G, Papp JG, Deli MA. Vasoactive substances produced by cultured rat brain endothelial cells. Eur J Pharmacol 1999; 368:35-42. [PMID: 10096767 DOI: 10.1016/s0014-2999(99)00024-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The vasoactive substances synthesized by primary cultures of rat brain endothelial cells were investigated and compared to those from two, immortalized cell lines, RBE4 and GP8. The vasoactivity of endothelium-derived substances was measured on isolated canine coronary artery. Vascular tone was significantly decreased by both primary and GP8, but not by RBE4 cells. Indomethacin pretreatment of primary and GP8 cells turned vasorelaxation into contraction while N(omega)-nitro-L-arginine pretreatment decreased the vasorelaxation induced by primary, but not by GP8 cells. Eicosanoid production was determined after incubation with [14C]arachidonic acid. The predominant vasoactive eicosanoid was prostaglandin E2 in both primary and GP8 cells. RBE4 cells synthetized mainly prostaglandin E2 and thromboxane B2 and significantly less prostaglandin E2 than did either primary or GP8 cells. The capacity of cerebral endothelium to regulate vascular tone by production of dilator and constrictor substances can be preserved under certain circumstances in immortalized cell lines.
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MESH Headings
- Animals
- Arachidonic Acid/biosynthesis
- Arachidonic Acid/pharmacology
- Brain/cytology
- Brain/drug effects
- Brain/metabolism
- Cell Line
- Cells, Cultured
- Coronary Vessels/drug effects
- Coronary Vessels/physiology
- Culture Media, Conditioned/chemistry
- Culture Media, Conditioned/pharmacology
- Cyclooxygenase Inhibitors/pharmacology
- Dinoprost/pharmacology
- Dogs
- Eicosanoids/biosynthesis
- Eicosanoids/pharmacology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Enzyme Inhibitors/pharmacology
- Female
- In Vitro Techniques
- Indomethacin/pharmacology
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Nitroarginine/pharmacology
- Rats
- Vasoconstriction/drug effects
- Vasoconstrictor Agents/metabolism
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- B Kis
- Department of Pathophysiology, Albert Szent-Györgyi Medical University, Szeged, Hungary.
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Gecse A, Kis B, Mezei Z, Telegdy G. Effects of inflammatory neuropeptides on the arachidonate cascade of platelets. Int Arch Allergy Immunol 1999; 118:166-70. [PMID: 10224368 DOI: 10.1159/000024057] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND During neurogenic inflammation, neuro-peptides (substance P, SP, calcitonin gene-related peptide, CGRP, and neurokinin A) are released from nerve endings, and these peptides initiate inflammatory reactions in the microcirculation. Platelets are one of the most important elements of the microcirculation. METHODS Our in vitro experiments were carried out to determine the effects of inflammatory neuropeptides (SP, and CGRP) on the arachidonate cascade of isolated rat platelets. Cells were labeled with 1-14C-arachidonic acid, then the eicosanoids were separated with overpressure thin-layer chromatography or high-performance liquid chromatography and were quantitatively determined with a liquid scintillation analyzer. RESULTS SP (10(-9) and 10(-8) mol/l) significantly increased the activity of the arachidonate cascade. The lipoxygenase pathway was significantly stimulated by SP (10(-11), 10(-9) and 10(-8) mol/l), while the cyclooxygenase system was inhibited by 10(-12) mol/l, and stimulated by 10(-9) mol/l SP. The dose-response curve of TxA2 to SP exhibited a similar pattern to that detected for the cyclooxygenase pathway. Among the vasodilator cyclooxygenase metabolites, only the synthesis of PGE2 was significantly elevated by SP (10(-9) mol/l ). CGRP either in low (10(-12)-10(-11) mol/l) or in high concentrations (10(-6) mol/l) activated the cyclooxygenase pathway, while it had no effect on the lipoxygenase pathway. CGRP (8-37), a specific CGRP1 receptor antagonist, inhibited the effects of CGRP. CONCLUSIONS Our data suggest that the arachidonate metabolites of platelets may play a role in the process of neurogenic inflammation.
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Affiliation(s)
- A Gecse
- Department of Pathophysiology, Albert Szent-Györgyi Medical University, Szeged, Hungary.
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Hill DJ, Griffiths DH, Rowley AF. Trout thrombocytes contain 12- but not 5-lipoxygenase activity. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1437:63-70. [PMID: 9931438 DOI: 10.1016/s1388-1981(98)00007-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fish thrombocytes are thought to be the evolutionary forerunners of mammalian platelets. Thrombocyte preparations made by conventional methods, such as density gradient centrifugation, contain other cell types such as neutrophilic granulocytes and lymphocytes that could interfere with subsequent experiments. In this study, rainbow trout thrombocytes were separated by density gradient centrifugation and further purified by magnetic cell sorting (MACS) using the thrombocyte specific monoclonal antibody, 30D8. Thrombocyte purity was assessed by reactivity to 30D8 using flow cytometry and immunocytochemistry. Following purification by density gradient centrifugation, thrombocytes were 66.9+/-9.2% (mean value+/-S.E.M., n=3) pure. Further purification by MACS significantly increased thrombocyte purity to 97.3+/-0.6%, whereas only 1.4% of the MACS -ve fraction were identified as these cells. Incubation of thrombocytes isolated by density gradient alone with calcium ionophore, A23187, generated a range of eicosanoids derived from arachidonic or eicosapentaenoic acids, namely, leukotriene (LT)B4, LTB5, lipoxin (LX)A4, LXA5, 12-hydroxyeicosatetraenoic acid (12-HETE) and 12-hydroxyeicosapentaenoic acid (12-HEPE). A similar eicosanoid generation profile was observed for cells in the MACS -ve fraction; however, MACS +ve cells (thrombocytes) generated no 4 or 5 series LT or LX but did generate significant amounts of the 12-lipoxygenase (LO) products, 12-HETE and 12-HEPE. These results indicate that trout thrombocytes contain no demonstrable 5-LO activity and like their mammalian counterparts possess 12-LO activity.
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Affiliation(s)
- D J Hill
- School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, UK
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