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El-Lakany MA, Fouda MA, El-Gowelli HM, El-Mas MM. Ovariectomy provokes inflammatory and cardiovascular effects of endotoxemia in rats: Dissimilar benefits of hormonal supplements. Toxicol Appl Pharmacol 2020; 393:114928. [PMID: 32092384 DOI: 10.1016/j.taap.2020.114928] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 01/31/2020] [Accepted: 02/20/2020] [Indexed: 12/18/2022]
Abstract
The female gender is protected against immunological complications of endotoxemia. Here we investigated whether gonadal hormone depletion by ovariectomy (OVX) uncovers inflammatory and cardiovascular effects of endotoxemia and whether these effects are reversed by hormone replacement therapies. Changes in inflammatory cytokines, blood pressure (BP), left ventricular (LV) function, and cardiac autonomic activity caused by lipopolysaccharide (LPS) in conscious female rats with different hormonal states were determined. In contrast to no effects in sham-operated females, treatment of OVX rats with LPS (i) decreased BP, (ii) increased spectral low-frequency/high-frequency ratio of HRV, denoting enhanced cardiac sympathetic dominance, (iii) attenuated reflex tachycardic responses to sodium nitroprusside, and (iv) increased systolic contractility (dP/dtmax). The developed hypotension was (i) fully eliminated in estrogen (E2)-pretreated OVX rats, (ii) partially counteracted after selective activation of estrogen receptor-α (PPT) or β (DPN). All estrogenic compounds abrogated LPS enhancement of cardiac sympathetic drive. However, PPT was more successful than E2 or DPN in compromising LPS depression in baroreflex activity and elevation in dP/dtmax. Molecular studies showed that PPT was most effective in attenuating the upregulated myocardial expressions of NF-κB and iNOS in endotoxic OVX rats. Myocardial expression of the defensive HSP70 was comparably increased by all estrogenic products. Except for improved cardiac spectral activity, none of these functional or molecular entities was affected by medroxyprogesterone acetate (MPA). Overall, our data suggest diverse therapeutic advantages for gonadal hormones in the worsened endotoxic complications in rats with surgical menopause, with probably more favorable role for ERα agonism within this context.
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Affiliation(s)
- Mohammed A El-Lakany
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Mohamed A Fouda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Hanan M El-Gowelli
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Mahmoud M El-Mas
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.
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Castardo-de-Paula JC, de Campos BH, de Jager L, Amorim EDT, Zanluqui NG, de Farias CC, Higachi L, Pinge-Filho P, Barbosa DS, Martins-Pinge MC. Effects of Inducible Nitric Oxide Synthase Inhibition on Cardiovascular Risk of Adult Endotoxemic Female Rats: Role of Estrogen. Front Physiol 2018; 9:1020. [PMID: 30108513 PMCID: PMC6079304 DOI: 10.3389/fphys.2018.01020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/10/2018] [Indexed: 01/23/2023] Open
Abstract
Aim: Autonomic modulation responds to ovarian hormones and estrogen increases nitric oxide bioavailability. Also, females have minor susceptibility to sepsis and a higher survival rate. However, few studies have evaluated the role of estrogen in cardiovascular, autonomic, and oxidative parameters during initial endotoxemia and under inducible nitric oxide synthase (iNOS) inhibition in female rats. Methods: Female wistar rats were subjected to ovariectomy and divided into three groups: OVX (ovariectomized), OVX+E (OVX plus daily estradiol) and SHAM (false surgery). After 8 weeks, mean arterial pressure (MAP) and heart rate (HR) were recorded in non-anesthetized catheterized rats, before and after intravenous LPS injection, preceded by S-methylisothiourea sulfate (SMT) injection, or sterile saline. Cardiovascular recordings underwent spectral analysis for evaluation of autonomic modulation. Two hours after LPS, plasma was collected to assess total radical-trapping antioxidant (TRAP), nitrite levels (NO2), lipoperoxidation (LOOH), and paraoxonase 1 (PON1) activity. Results: Two hours after LPS, females treated with SMT presented a decrease of MAP, when compared to saline-LPS groups. At this same time, all SMT+LPS groups presented an increase of sympathetic and a decrease of parasympathetic modulation of HR. Two hours after saline+LPS, OVX presented decreased total radical-trapping antioxidant (TRAP) compared to SHAM. When treated with SMT+LPS, OVX did not altered TRAP, while estradiol reduced LOOH levels. Conclusion: iNOS would be responsible for sympathetic inhibition and consumption of antioxidant reserves of females during endotoxemia, since iNOS is inhibited, treatment with estradiol could be protective in inflammatory challenges.
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Affiliation(s)
| | - Blenda H de Campos
- Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
| | - Lorena de Jager
- Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
| | - Eric D T Amorim
- Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
| | - Nágela G Zanluqui
- Department of Pathological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
| | - Carine C de Farias
- Department of Pathology, Clinical and Toxicological Analysis, Center of Health Sciences, University Hospital, State University of Londrina, Londrina, Brazil
| | - Luciana Higachi
- Department of Pathology, Clinical and Toxicological Analysis, Center of Health Sciences, University Hospital, State University of Londrina, Londrina, Brazil
| | - Phileno Pinge-Filho
- Department of Pathological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
| | - Décio S Barbosa
- Department of Pathology, Clinical and Toxicological Analysis, Center of Health Sciences, University Hospital, State University of Londrina, Londrina, Brazil
| | - Marli C Martins-Pinge
- Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
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Qadri F, Rimmele F, Mallis L, Häuser W, Dendorfer A, Jöhren O, Dominiak P, Leeb-Lundberg LF, Bader M. Acute hypothalamo-pituitary-adrenal axis response to LPS-induced endotoxemia: expression pattern of kinin type B1 and B2 receptors. Biol Chem 2016; 397:97-109. [DOI: 10.1515/hsz-2015-0206] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 10/07/2015] [Indexed: 11/15/2022]
Abstract
Abstract
Bradykinin (BK) and des-Arg9-BK are pro-inflammatory mediators acting via B2 (B2R) and B1 (B1R) receptors, respectively. We investigated the role of B2R and B1R in lipopolysaccharide (LPS)-induced hypothalamo-pituitary-adrenal (HPA) axis activation in SD rats. LPS given intraperitoneally (ip) up-regulated B1R mRNA in the hypothalamus, both B1R and B2R were up-regulated in pituitary and adrenal glands. Receptor localization was performed using immunofluorescence staining. B1R was localized in the endothelial cells, nucleus supraopticus (SON), adenohypophysis and adrenal cortex. B2R was localized nucleus paraventricularis (PVN) and SON, pituitary and adrenal medulla. Blockade of B1R prior to LPS further increased ACTH release and blockade of B1R 1 h after LPS decreased its release. In addition, we evaluated if blockade of central kinin receptors influence the LPS-induced stimulation of hypothalamic neurons. Blockade of both B1R and B2R reduced the LPS-induced c-Fos immunoreactivity in the hypothalamus. Our data demonstrate that a single injection of LPS induced a differential expression pattern of kinin B1R and B2R in the HPA axis. The tissue specific cellular localization of these receptors indicates that they may play a crucial role in the maintenance of body homeostasis during endotoxemia.
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Goldsmith M, Avni D, Ernst O, Glucksam Y, Levy-Rimler G, Meijler MM, Zor T. Synergistic IL-10 induction by LPS and the ceramide-1-phosphate analog PCERA-1 is mediated by the cAMP and p38 MAP kinase pathways. Mol Immunol 2009; 46:1979-87. [PMID: 19362373 DOI: 10.1016/j.molimm.2009.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 03/08/2009] [Accepted: 03/14/2009] [Indexed: 01/13/2023]
Abstract
Expression of the anti-inflammatory cytokine IL-10 can be induced either by TLR agonists such as lipopolysaccharide (LPS), or by various endogenous stimuli, in particular those acting via a cAMP-dependent signaling pathway. We have previously reported that the synthetic phospho-ceramide analogue-1 (PCERA-1) increases cAMP level and subsequently down-regulates production of TNFalpha and up-regulates production of IL-10 in LPS-stimulated macrophages. The objective of this study was to determine the mechanism of activity of PCERA-1 and the role of cAMP in LPS-induced IL-10 production. We show here that PCERA-1 induces IL-10 production in synergism with various TLR agonists in mouse RAW264.7 macrophages. Cooperativity is evident both at the mRNA and protein levels. IL-10 production by LPS and PCERA-1 is mediated by the cAMP pathway and by the p38 MAP kinase. Phosphorylation of p38 is cooperatively accomplished by LPS and PCERA-1 or other cAMP inducers. Furthermore, the activity of PCERA-1 can be partially mimicked by a cell-permeable analog of cAMP, and blocked by the protein kinase A (PKA) inhibitor H89. Finally, in the absence of PCERA-1, the residual IL-10 induction by LPS depends on the basal cAMP level as it can be largely elevated by the phosphodiesterase (PDE)-4 inhibitor rolipram. Our results thus indicate that IL-10 induction by LPS critically depends on basal cAMP level, and that a co-stimulus by a TLR agonist and a cAMP-elevating agent results in synergistic PKA-dependent and p38-dependent IL-10 production.
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Affiliation(s)
- Meir Goldsmith
- Department of Biochemistry, Life Sciences Institute, Tel-Aviv University, Tel-Aviv 69978, Israel
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Lin WC, Tsai PS, Huang CJ. Catecholamines' enhancement of inducible nitric oxide synthase-induced nitric oxide biosynthesis involves CAT-1 and CAT-2A. Anesth Analg 2005; 101:226-32, table of contents. [PMID: 15976236 DOI: 10.1213/01.ane.0000153860.71992.29] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Catecholamines enhance inducible nitric oxide synthase (iNOS) expression that results in nitric oxide (NO) overproduction in lipopolysaccharide (LPS)-stimulated macrophages. L-arginine transport mediated by cationic amino acid transporters (including CAT-1, CAT-2, CAT-2A, and CAT-2B) is crucial in regulating iNOS activity. We sought to assess the effects of catecholamines on L-arginine transport and CAT isozyme expression in stimulated macrophages. Confluent RAW264.7 cells were cultured with LPS with or without catecholamines (epinephrine or norepinephrine, 5 x 10(-6) M) for 18 h. NO production, L-arginine transport, and enzyme expression were determined. Our data revealed that LPS co-induced iNOS, CAT-2, and CAT-2B expression, whereas CAT-1 and CAT-2A expression remained unaffected. Significant increases in NO production and L-arginine transport (approximately eight-fold and three-fold increases, respectively) were found in activated macrophages. Catecholamines significantly enhanced NO production and L-arginine transport (approximately 30% and 20% increases, respectively) in activated macrophages. Catecholamines also enhanced the expression of iNOS, CAT-1, and CAT-2A but not CAT-2 or CAT-2B in LPS-stimulated macrophages. Furthermore, the enhancement effects of catecholamines were inhibited by either dexamethasone or propranolol. We provide the first evidence to indicate that L-arginine transport in activated macrophages could be enhanced by catecholamines. Furthermore, this catecholamine-enhanced L-arginine transport might involve CAT-1 and CAT-2A but not CAT-2 or CAT-2B.
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Affiliation(s)
- Wen-Chou Lin
- Department of Urology, Mackay Memorial Hospital, 92 s. 2 Chung San N. Rd., Taipei 104, Taiwan, Republic of China
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Bouallegue A, Yamaguchi N. Nitric oxide inhibits the bradykinin B2 receptor-mediated adrenomedullary catecholamine release but has no effect on adrenal blood flow response in vivo. J Pharmacol Sci 2005; 98:151-60. [PMID: 15942127 DOI: 10.1254/jphs.fpj04048x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The role of nitric oxide (NO) in bradykinin (BK)-induced adrenal catecholamine secretion still remains obscure. The present study was to investigate whether an inhibition of NO synthase with N(omega)-nitro-L-arginine methyl ester (L-NAME) would modulate BK-induced adrenal catecholamine secretion (ACS) and adrenal vasodilating response (AVR) in anesthetized dogs. Plasma catecholamine concentrations were determined with an HPLC coupled with an electrochemical detector. All drugs were locally administered to the left adrenal gland via intra-arterial infusion. BK dose-dependently increased both ACS and AVR. Hoe-140, a selective B(2) antagonist, significantly blocked the BK-induced increases in both ACS and AVR. In the presence of L-NAME, the BK-induced ACS was significantly enhanced, while the simultaneous AVR remained unaffected. These results suggest that the both BK-induced ACS and AVR are primarily mediated by B(2) receptors in the canine adrenal gland. Our results also suggest that the enhanced ACS in response to BK in the presence of L-NAME may have resulted from a specific inhibition of NO formation in the adrenal gland. It is concluded that the BK-induced NO may play an inhibitory role in the B(2)-receptor-mediated mechanisms regulating ACS, while it may not be implicated in the B(2)-receptor-mediated AVR under in vivo conditions.
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Affiliation(s)
- Ali Bouallegue
- The Autonomic Nervous System Research Group, Faculty of Pharmacy, University of Montreal, Quebec, Canada
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Hsu DZ, Liu MY. Involvement of nitric oxide in gastric protection of epinephrine in endotoxin intoxication in rats. Toxicology 2004; 204:203-8. [PMID: 15388246 DOI: 10.1016/j.tox.2004.06.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 03/21/2004] [Accepted: 06/23/2004] [Indexed: 11/19/2022]
Abstract
Reduction in blood pressure may cause gastric mucosal hypoxia and injury during endotoxin intoxication. Epinephrine is found to increase gastric mucosal perfusion while managing hypotension. Nitric oxide plays an important role in regulating gastric mucosal perfusion and maintaining gastric integrity. The aim of this study was to investigate the involvement of nitric oxide in the gastric protection of epinephrine by determining gastric mucosal lipid peroxidation, ulceration, and hemorrhage levels in endotoxin intoxication in rats. Epinephrine significantly increased gastric mucosal nitrite levels, decreased gastric mucosal lipid peroxidation levels, and ameliorated gastric ulceration and hemorrhage in endotoxin-treated rats. Furthermore, nitric oxide synthase inhibitors potently reversed the effects of epinephrine on gastric mucosa in endotoxin-treated rats. It was suggested that nitric oxide might be involved in the protective effect of epinephrine on gastric mucosal injury in endotoxin intoxication in rats.
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Affiliation(s)
- Dur-Zong Hsu
- Department of Environmental and Occupational Health, and Institute of Basic Medical Sciences, National Cheng Kung University Medical College, 138 Sheng-Li Road, Tainan 704, Taiwan
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Pickkers P, Jansen Van Rosendaal AJ, Van Der Hoeven JG, Smits P. ACTIVATION OF THE ATP-DEPENDENT POTASSIUM CHANNEL ATTENUATES NOREPINEPHRINE-INDUCED VASOCONSTRICTION IN THE HUMAN FOREARM. Shock 2004; 22:320-5. [PMID: 15377886 DOI: 10.1097/01.shk.0000142250.85264.10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sepsis-induced vasodilation is characterized by an attenuated sensitivity to vasoconstrictor substances such as norepinephrine, possibly mediated by activation of vascular potassium channels. We determined whether vasodilation associated with potassium channel activation resulted in an attenuated vasoconstrictive response to norepinephrine in humans and whether the vasodilation associated with potassium channel activation could be inhibited by pharmacological potassium channel blockers. In 30 volunteers, the brachial artery was cannulated for infusion of drugs. Forearm blood flow (FBF) was measured in both arms using strain-gauge venous occlusion plethysmography. Forearm vascular resistance (FVR, mean arterial pressure/FBF) was calculated. The effects of vasodilation induced by sodium nitroprusside (SNP, nitric oxide donor) or diazoxide (activator of the ATP-dependent potassium channel) on norepinephrine-mediated vasoconstriction were examined. Also, the effects of potassium channel blockers on vasodilation associated with potassium channel activation were determined. Intraarterial SNP infusion (2 microg/min/dL) increased forearm blood flow by 235%, from (mean +/- SEM) 2.8 +/- 0.7 to 9.4 +/- 1.5 mL/min/dL (P < 0.0001). Subsequent norepinephrine infusion (10, 30, 100, 300, 1000 ng/min/dL) increased FVR dose-dependently from 13 +/- 4 AU to 249 +/- 45 AU at the highest norepinephrine infusion. Intraarterial diazoxide infusion (1 mg/min/dL) increased FBF by 209% from 2.2 +/- 0.3 to 6.8 +/- 1.0 mL/min/dL (P < 0.001). Subsequent norepinephrine infusion increased FVR from 18 +/- 5 to 51 +/- 6 AU at the highest norepinephrine infusion rate (n = 10), significantly different from the norepinephrine-induced effects during SNP coinfusion (P < 0.001). Diazoxide-induced fall in FVR in the infused forearm was inhibited by potassium channel blockers tetraethyl ammonium (1 mg/min/dL, n = 10, P = 0.004) and quinine (50 microg/min/dL, n = 10, P = 0.016). Vasodilation induced by vascular potassium channel activation is associated with an impressive reduction in the vasoconstrictor response to norepinephrine in humans. In accordance with animal experiments, this indicates that potassium channel activation could account for the diminished norepinephrine sensitivity in septic patients. Vasodilation associated with potassium channel activation can be inhibited by pharmacological potassium channel blockade. The possible role of potassium channel blockers during sepsis-induced potassium channel activation and vasodilation in humans needs further elucidation.
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Affiliation(s)
- Peter Pickkers
- Department of Intensive Care Medicine,University Medical Centre St. Radboud, Nijmegen, The Netherlands.
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N/A. N/A. Shijie Huaren Xiaohua Zazhi 2004; 12:1506-1507. [DOI: 10.11569/wcjd.v12.i6.1506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Mitaka C, Hirata Y, Yokoyama K, Wakimoto H, Hirokawa M, Nosaka T, Imai T. Relationships of circulating nitrite/nitrate levels to severity and multiple organ dysfunction syndrome in systemic inflammatory response syndrome. Shock 2003; 19:305-9. [PMID: 12688539 DOI: 10.1097/00024382-200304000-00002] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Excessive nitric oxide (NO) production has been implicated to be responsible for the development of septic shock. To determine whether plasma nitrite/nitrate (NOx) levels are related to the severity of systemic inflammatory response syndrome (SIRS) and the degree of multiple organ dysfunction, we studied plasma NOx levels in 70 patients with SIRS consisting of noninfectious SIRS (n = 32), sepsis (n = 23), and septic shock (n = 15). Infection is a microbial phenomenon characterized by an inflammatory response to the presence of microorganism. Positive culture for microorganism is regarded as infectious SIRS (sepsis and septic shock) and negative culture is regarded as noninfectious SIRS. Plasma samples collected from each patient within 24 h from admission to the intensive care unit were subjected for measurement of NOx levels, the stable end products of NO, by the high performance liquid chromatography-Greiss system. Mean plasma NOx levels in patients with SIRS were 52.8 +/- 44 microM/L, ranging from 8.1 to 186.2 microM/L. Plasma NOx levels were positively correlated with Acute Physiology, Age, and Chronic Health Evaluation (APACHE) III score (r = 0.414, P < 0.01) and sequential organ failure assessment (SOFA) score (r = 0.433, P < 0.01). Plasma NOx levels in patients with sepsis (51.0 +/- 38.5 microM/L) and septic shock (94.5 +/- 53.7 microM/L) were significantly (P < 0.01) higher than those in patients with noninfectious SIRS (25.8 +/- 16.9 microM/L) and healthy subjects (29.6 +/- 8.9 microM/L). Our study shows that plasma NOx levels are increased in patients with infectious, but not noninfectious SIRS, which increase as the severity of SIRS and the development of multiple organ dysfunction syndrome, suggesting its possible pathogenic role in SIRS.
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Affiliation(s)
- Chieko Mitaka
- Department of Critical Care Medicine, Tokyo Medical and Dental University Graduate School, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
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Ralevic V, Farmer MR, Gardiner SM. Vasoconstrictor responsiveness of tail arteries from endotoxaemic rats. Eur J Pharmacol 2003; 460:145-53. [PMID: 12559375 DOI: 10.1016/s0014-2999(02)02917-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Continuous infusion of lipopolysaccharide in conscious rats mimics some aspects of cardiovascular dysfunction in septic shock. In the present study, contractile responsiveness of tail arteries taken from rats infused with lipopolysaccharide was investigated. Contractile responses to alpha,beta-methylene ATP and potassium chloride, but not to methoxamine, were greater after 24 h lipopolysaccharide infusion than in 2-h saline, 24-h saline and 2-h lipopolysaccharide groups. N(G)-nitro-L-arginine methyl ester augmented contractions to alpha,beta-methylene ATP and methoxamine in the 2-h saline, 24-h saline and 2-h lipopolysaccharide groups, but had no significant effect in the 24-h lipopolysaccharide group. Endothelium-independent vasorelaxant responses to sodium nitroprusside were greater in the 24-h lipopolysaccharide group compared to the other three groups. Relaxations to acetylcholine were not significantly different. In vitro incubation in medium containing lipopolysaccharide for 24 h had no significant effect on contractile responses of tail arteries compared to controls incubated in medium alone. These data indicate a possible impaired nitric oxide and/or endothelial function in tail arteries isolated from rats 24 h after lipopolysaccharide infusion. As hypercontractility was not evoked following in vitro incubation with lipopolysaccharide, the involvement of in vivo neurohumoral factors/mechanisms in the pathology of these changes is implicated.
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Affiliation(s)
- Vera Ralevic
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Clifton Boulevard, Nottingham NG7 2UH, United Kingdom.
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Beach PK, Spain DA, Kawabe T, Harris PD, Garrison RN. Sepsis increases NOS-2 activity and decreases non-NOS-mediated acetylcholine-induced dilation in rat aorta. J Surg Res 2001; 96:17-22. [PMID: 11180991 DOI: 10.1006/jsre.2000.6056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Acetylcholine (Ach) is frequently used to assess endothelium-dependent vasodilation during sepsis. However, the effects of sepsis on constitutive nitric oxide synthase activity (NOS-1 and -3) and other non-NOS effects of Ach are unclear. METHODS Sepsis was induced in rats by inoculation of an implanted sponge with Escherichia coli and Bacteroides fragilis (10(9) CFU each). Thoracic aortic rings (2 mm) were harvested at 24 h from septic (N = 9) and control (N = 9) rats and were suspended in physiological salt solution (PSS), PSS + l-N(6)-(1-iminoethyl)lysine (l-NIL: NOS-2 inhibitor, 10 microM), or PSS + l-N(G)-monomethylarginine (l-NMMA: NOS-1, -2, and -3 inhibitor, 60 microM). Rings were set at 1-g preload and precontracted with phenlyephrine (10(-8) M). Relaxation dose-response curves were generated with six doses of Ach (3 x 10(-8) to 10(-5) M). RESULTS Sepsis increased the maximal relaxation to Ach under basal conditions. NOS 2 inhibition with l-NIL decreased Ach-induced relaxation in controls (66% vs 84%, P < 0.05, two-way ANOVA) and more so in septic rats (44% vs 93%, P < 0.05). Total NOS inhibition with l-NMMA decreased Ach-induced relaxation to 45% (P < 0.05) in controls and to 30% (P < 0.05) in septic animals. CONCLUSIONS Inhibition of NOS-1, -2, and -3 failed to abolish Ach-induced relaxation, suggesting the presence of other Ach-induced vasodilator mechanisms. NOS-2 inhibition reduced Ach-induced relaxation by 20-25% in the normal thoracic aorta, but by 50% in septic animals. The remaining Ach-induced non-NOS vasodilation (after inhibition of NOS-1 + NOS-2 + NOS-3) was reduced from 45% in normals to 30% in septic animals. Vascular dysregulation in sepsis is a complex event involving increased NOS-2, decreased NOS-1 + NOS-3, and decreased Ach-induced non-NOS vasodilator mechanisms.
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Affiliation(s)
- P K Beach
- Department of Surgery, University of Louisville, Louisville, Kentucky 40292, USA
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