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Manneck D, Manz G, Braun HS, Rosendahl J, Stumpff F. The TRPA1 Agonist Cinnamaldehyde Induces the Secretion of HCO 3- by the Porcine Colon. Int J Mol Sci 2021; 22:ijms22105198. [PMID: 34068986 PMCID: PMC8156935 DOI: 10.3390/ijms22105198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 02/07/2023] Open
Abstract
A therapeutic potential of the TRPA1 channel agonist cinnamaldehyde for use in inflammatory bowel disease is emerging, but the mechanisms are unclear. Semi-quantitative qPCR of various parts of the porcine gastrointestinal tract showed that mRNA for TRPA1 was highest in the colonic mucosa. In Ussing chambers, 1 mmol·L-1 cinnamaldehyde induced increases in short circuit current (ΔIsc) and conductance (ΔGt) across the colon that were higher than those across the jejunum or after 1 mmol·L-1 thymol. Lidocaine, amiloride or bumetanide did not change the response. The application of 1 mmol·L-1 quinidine or the bilateral replacement of 120 Na+, 120 Cl- or 25 HCO3- reduced ΔGt, while the removal of Ca2+ enhanced ΔGt with ΔIsc numerically higher. ΔIsc decreased after 0.5 NPPB, 0.01 indometacin and the bilateral replacement of 120 Na+ or 25 HCO3-. The removal of 120 Cl- had no effect. Cinnamaldehyde also activates TRPV3, but comparative measurements involving patch clamp experiments on overexpressing cells demonstrated that much higher concentrations are required. We suggest that cinnamaldehyde stimulates the secretion of HCO3- via apical CFTR and basolateral Na+-HCO3- cotransport, preventing acidosis and damage to the epithelium and the colonic microbiome. Signaling may involve the opening of TRPA1, depolarization of the epithelium and a rise in PGE2 following a lower uptake of prostaglandins via OATP2A1.
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Affiliation(s)
- David Manneck
- Department of Veterinary Medicine, Institute of Veterinary Physiology, Freie Universität Berlin, Oertzenweg 19b, 14163 Berlin, Germany; (D.M.); (G.M.)
| | - Gisela Manz
- Department of Veterinary Medicine, Institute of Veterinary Physiology, Freie Universität Berlin, Oertzenweg 19b, 14163 Berlin, Germany; (D.M.); (G.M.)
| | - Hannah-Sophie Braun
- PerformaNat GmbH, Hohentwielsteig 6, 14163 Berlin, Germany; (H.-S.B.); (J.R.)
| | - Julia Rosendahl
- PerformaNat GmbH, Hohentwielsteig 6, 14163 Berlin, Germany; (H.-S.B.); (J.R.)
| | - Friederike Stumpff
- Department of Veterinary Medicine, Institute of Veterinary Physiology, Freie Universität Berlin, Oertzenweg 19b, 14163 Berlin, Germany; (D.M.); (G.M.)
- Correspondence: ; Tel.: +49-30-838-62595
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Sallam MY, El-Gowilly SM, El-Mas MM. Androgenic modulation of arterial baroreceptor dysfunction and neuroinflammation in endotoxic male rats. Brain Res 2021; 1756:147330. [PMID: 33539800 DOI: 10.1016/j.brainres.2021.147330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 01/04/2021] [Accepted: 01/22/2021] [Indexed: 01/01/2023]
Abstract
Autonomic neuropathy contributes to cardiovascular derangements induced by endotoxemia. In this communication, we tested the hypothesis that androgenic hormones improve arterial baroreflex dysfunction and predisposing neuroinflammatory response caused by endotoxemia in male rats. Baroreflex curves relating changes in heart rate to increases or decreases in blood pressure evoked by phenylephrine (PE) and sodium nitroprusside (SNP), respectively, were constructed in conscious sham-operated, castrated, and testosterone-replaced castrated rats treated with or without lipopolysaccharide (LPS, 10 mg/kg i.v.). Slopes of baroreflex curves were taken as measures of baroreflex sensitivity (BRS). In sham rats, LPS significantly reduced reflex bradycardia (BRSPE) and tachycardia (BRSSNP) and increased immunohistochemical expression of nuclear factor kappa B (NFκB) in heart and brainstem neurons of nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (RVLM). The baroreflex depressant effect of LPS was maintained in castrated rats despite the remarkably attenuated inflammatory response. Testosterone replacement of castrated rats counteracted LPS-evoked BRSPE, but not BRSSNP, depression and increased cardiac, but not neuronal, NFκB expression. We also evaluated whether LPS responses could be affected following pharmacologic inhibition of androgenic biosynthetic pathways. Whereas none of LPS effects were altered in rats pretreated with formestane (aromatase inhibitor) or finasteride (5α-reductase inhibitor), the LPS-evoked BRSPE, but not BRSSNP, depression and cardiac and neuronal inflammation disappeared in rats pretreated with degarelix (gonadotropin-releasing hormone receptor blocker). Overall, despite the seemingly provocative role for the hypothalamic-pituitary-gonadal axis in the neuroinflammatory and baroreflex depressant effects of LPS, testosterone appears to distinctly modulate the two LPS effects.
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Affiliation(s)
- Marwa Y Sallam
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University Alexandria, Egypt
| | - Sahar M El-Gowilly
- 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; Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, Kuwait.
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Kim M, Lee SW, Kim J, Shin Y, Chang F, Kim JM, Cong X, Yu GY, Park K. LPS-induced epithelial barrier disruption via hyperactivation of CACC and ENaC. Am J Physiol Cell Physiol 2021; 320:C448-C461. [PMID: 33471620 DOI: 10.1152/ajpcell.00295.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Gram-negative bacterial lipopolysaccharide (LPS) increases the susceptibility of cells to pathogenic diseases, including inflammatory diseases and septic syndrome. In our experiments, we examined whether LPS induces epithelial barrier disruption in secretory epithelia and further investigated its underlying mechanism. The activities of Ca2+-activated Cl- channels (CACC) and epithelial Na+ channels (ENaC) were monitored with a short-circuit current using an Ussing chamber. Epithelial membrane integrity was estimated via transepithelial electrical resistance and paracellular permeability assays. We found that the apical application of LPS evoked short-circuit current (Isc) through the activation of CACC and ENaC. Although LPS disrupted epithelial barrier integrity, this was restored with the inhibition of CACC and ENaC, indicating the role of CACC and ENaC in the regulation of paracellular pathways. We confirmed that LPS, CACC, or ENaC activation evoked apical membrane depolarization. The exposure to a high-K+ buffer increased paracellular permeability. LPS induced the rapid redistribution of zonula occludens-1 (ZO-1) and reduced the expression levels of ZO-1 in tight junctions through apical membrane depolarization and tyrosine phosphorylation. However, the LPS-induced epithelial barrier disruption and degradation of ZO-1 were largely recovered by blocking CACC and ENaC. Furthermore, although LPS-impaired epithelial barrier became vulnerable to secondary bacterial infections, this vulnerability was prevented by inhibiting CACC and ENaC. We concluded that LPS induces the disruption of epithelial barrier integrity through the activation of CACC and ENaC, resulting in apical membrane depolarization and the subsequent tyrosine phosphorylation of ZO-1.
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Affiliation(s)
- Minkyoung Kim
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
| | - Sang-Woo Lee
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
| | - Junchul Kim
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
| | - Yonghwan Shin
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
| | - Fengjiao Chang
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
| | - Jin Man Kim
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
| | - Xin Cong
- Department of Physiology and Pathophysiology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Guang-Yan Yu
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Kyungpyo Park
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul, South Korea
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Sallam MY, El-Gowilly SM, Fouda MA, Abd-Alhaseeb MM, El-Mas MM. Brainstem cholinergic pathways diminish cardiovascular and neuroinflammatory actions of endotoxemia in rats: Role of NFκB/α7/α4β2AChRs signaling. Neuropharmacology 2019; 157:107683. [DOI: 10.1016/j.neuropharm.2019.107683] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/16/2019] [Accepted: 06/23/2019] [Indexed: 12/20/2022]
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Mota CMD, Borges GS, Amorim MR, Carolino ROG, Batalhão ME, Anselmo-Franci JA, Carnio EC, Branco LGS. Central serotonin prevents hypotension and hypothermia and reduces plasma and spleen cytokine levels during systemic inflammation. Brain Behav Immun 2019; 80:255-265. [PMID: 30885841 DOI: 10.1016/j.bbi.2019.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 02/06/2023] Open
Abstract
An exceptionally high mortality rate is observed in sepsis and septic shock. Systemic administration of lipopolysaccharide (LPS) has been used as an experimental model for sepsis resulting in an exacerbated immune response, brain neurochemistry adjustments, hypotension, and hypothermia followed by fever. Central serotonergic pathways not only modulate systemic inflammation (SI) but also are affected by SI, including in the anteroventral region of the hypothalamus (AVPO), which is the hierarchically most important region for body temperature (Tb) control. In this study, we sought to determine if central serotonin (5-HT) plays a role in SI induced by intravenous administration of LPS (1.5 mg/kg) in male Wistar rats (280-350 g) by assessing 5-HT levels in the AVPO, mean arterial pressure, heart rate, and Tb up to 300 min after LPS administration, as well as assessing plasma and spleen cytokine levels, nitric oxide (NO) plasma levels, and prostaglandin (PG) E2 levels in the AVPO at 75 min and 300 min after LPS administration. We observed reduced AVPO 5-HT levels, hypotension, tachycardia, hypothermia followed by fever, as well as observing increased plasma NO, plasma and spleen cytokines and AVPO PGE2 levels in SI. Intracerebroventricular (icv) administration of 5-HT 30 min before LPS administration prevented hypotension and hypothermia, which were accompanied by reduced plasma NO, as well as plasma TNF-α, IL-1β, IL-6, and IL-10 and spleen TNF-α and IL-10 levels. We suggest that SI reduced 5-HT levels in the AVPO favor an increased pro-inflammatory status both centrally and peripherally that converge to hypotension and hypothermia. Moreover, our results are consistent with the notion that exogenous 5-HT given icv prevents hypotension and hypothermia probably activating the splenic anti-inflammatory pathway.
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Affiliation(s)
- Clarissa M D Mota
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Gabriela S Borges
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Mateus R Amorim
- Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ruither O G Carolino
- Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Marcelo E Batalhão
- Nursing School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Janete A Anselmo-Franci
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Evelin C Carnio
- Nursing School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luiz G S Branco
- Department of Physiology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil; Department of Morphology, Physiology and Basic Pathology, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
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Steiner AA, Flatow EA, Brito CF, Fonseca MT, Komegae EN. Respiratory gas exchange as a new aid to monitor acidosis in endotoxemic rats: relationship to metabolic fuel substrates and thermometabolic responses. Physiol Rep 2017; 5:5/1/e13100. [PMID: 28082427 PMCID: PMC5256159 DOI: 10.14814/phy2.13100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/01/2016] [Accepted: 12/03/2016] [Indexed: 11/26/2022] Open
Abstract
This study introduces the respiratory exchange ratio (RER; the ratio of whole‐body CO2 production to O2 consumption) as an aid to monitor metabolic acidosis during the early phase of endotoxic shock in unanesthetized, freely moving rats. Two serotypes of lipopolysaccharide (lipopolysaccharide [LPS] O55:B5 and O127:B8) were tested at shock‐inducing doses (0.5–2 mg/kg). Phasic rises in RER were observed consistently across LPS serotypes and doses. The RER rise often exceeded the ceiling of the quotient for oxidative metabolism, and was mirrored by depletion of arterial bicarbonate and decreases in pH. It occurred independently of ventilatory adjustments. These data indicate that the rise in RER results from a nonmetabolic CO2 load produced via an acid‐induced equilibrium shift in the bicarbonate buffer. Having validated this new experimental aid, we asked whether acidosis was interconnected with the metabolic and thermal responses that accompany endotoxic shock in unanesthetized rats. Contrary to this hypothesis, however, acidosis persisted regardless of whether the ambient temperature favored or prevented downregulation of mitochondrial oxidation and regulated hypothermia. We then asked whether the substrate that fuels aerobic metabolism could be a relevant factor in LPS‐induced acidosis. Food deprivation was employed to divert metabolism away from glucose oxidation and toward fatty acid oxidation. Interestingly, this intervention attenuated the RER response to LPS by 58%, without suppressing other key aspects of systemic inflammation. We conclude that acid production in unanesthetized rats with endotoxic shock results from a phasic activation of glycolysis, which occurs independently of physiological changes in mitochondrial oxidation and body temperature.
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Affiliation(s)
- Alexandre A Steiner
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Elizabeth A Flatow
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Camila F Brito
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Monique T Fonseca
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Evilin N Komegae
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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7
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Millington WR, Yilmaz MS, Feleder C. The initial fall in arterial pressure evoked by endotoxin is mediated by the ventrolateral periaqueductal gray. Clin Exp Pharmacol Physiol 2017; 43:612-5. [PMID: 27009880 DOI: 10.1111/1440-1681.12573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/04/2016] [Accepted: 03/21/2016] [Indexed: 11/29/2022]
Abstract
This study tested the hypothesis that the initial fall in arterial pressure evoked by lipopolysaccharide (LPS) is mediated by the ventrolateral column of the midbrain periaqueductal gray region (vlPAG). To test this hypothesis, the local anaesthetic lidocaine (2%; 0.1 μL, 0.2 μL or 1.0 μL), the delta opioid receptor antagonist naltrindole (2 nmol) or saline was microinjected into the vlPAG of isoflurane-anaesthetized rats bilaterally and LPS (1 mg/kg) or saline was administered intravenously 2 min later. Both lidocaine and naltrindole inhibited LPS-evoked hypotension significantly but did not affect arterial pressure in saline-treated control animals. Neither lidocaine nor naltrindole altered heart rate significantly in either LPS-treated or control animals. Microinjection of lidocaine or naltrindole into the dorsolateral PAG was ineffective. These data indicate that the vlPAG plays an important role in the initiation of endotoxic hypotension and further show that delta opioid receptors in the vlPAG participate in the response.
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Affiliation(s)
- William R Millington
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | - M Sertac Yilmaz
- Department of Medical Pharmacology, Faculty of Medicine, Uludag University, Bursa, Turkey
| | - Carlos Feleder
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
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8
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Abstract
BACKGROUND How vagotomy affects host responses to gut ischemia-reperfusion (I/R) is unclear. MATERIALS AND METHODS Experiment 1: male Institute of Cancer Research mice (n = 22) were assigned to the I/R or the vago-I/R group. The I/R mice underwent 45-min superior mesenteric artery (SMA) occlusion. The vago-I/R mice received vagotomy before SMA occlusion. Survival was observed for 48 h.Experiment 2: mice (n = 55) were divided into four groups (Sham, vago, I/R, vago-I/R). Sham and vago groups did not undergo gut I/R. Mice were killed at 3 or 6 h after reperfusion, and cytokine levels in the plasma, jejunum, and ileum were evaluated. In addition, gut histology at 6 h was examined.Experiment 3: mice (n = 24) were divided into four groups as in Experiment 2. The small intestine was harvested at 3 h after reperfusion and the tissue was cultured ex vivo for 3 h. Cytokine levels of the culture supernatant were then measured. RESULTS Experiment 1: survival was significantly worse with vago-I/R than I/R.Experiment 2: along with severe gut injury, vago-I/R increased IL-6 and monocyte chemoattractant protein-1 (MCP-1) in plasma, IFN-γ in the jejunum and MCP-1 in the ileum, as compared with I/R. Significant positive correlations were noted between plasma and intestinal levels of pro-inflammatory cytokines (IL-6, MCP-1, and TNF-α).Experiment 3: MCP-1 in the jejunal culture medium was higher in the vago-I/R than in the I/R group. CONCLUSIONS Vagotomy worsens survival after gut I/R, together with increases in pro-inflammatory cytokines in both plasma and the gut in association with severe intestinal tissue damage.
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Göktalay G, Millington WR. Hypovolemic hemorrhage induces Fos expression in the rat hypothalamus: Evidence for involvement of the lateral hypothalamus in the decompensatory phase of hemorrhage. Neuroscience 2016; 322:464-78. [PMID: 26947128 DOI: 10.1016/j.neuroscience.2016.02.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 02/10/2016] [Accepted: 02/27/2016] [Indexed: 01/02/2023]
Abstract
This study tested the hypothesis that the hypothalamus participates in the decompensatory phase of hemorrhage by measuring Fos immunoreactivity and by inhibiting neuronal activity in selected hypothalamic nuclei with lidocaine or cobalt chloride. Previously, we reported that inactivation of the arcuate nucleus inhibited, but did not fully prevent, the fall in arterial pressure evoked by hypotensive hemorrhage. Here, we report that hemorrhage (2.2 ml/100g body weight over 20 min) induced Fos expression in a high percentage of cells in the paraventricular, supraoptic and arcuate nuclei of the hypothalamus as shown previously. Lower densities of Fos immunoreactive cells were also found in the medial preoptic area (mPOA), anterior hypothalamus, lateral hypothalamus (LH), dorsomedial hypothalamus, ventromedial hypothalamus (VMH) and posterior hypothalamus. Bilateral injection of lidocaine (2%; 0.1 μl or 0.3 μl) or cobalt chloride (5mM; 0.3 μl) into the tuberal portion of the LH immediately before hemorrhage was initiated reduced the magnitude of hemorrhagic hypotension and bradycardia significantly. Lidocaine injection into the VMH also attenuated the fall in arterial pressure and heart rate evoked by hemorrhage although inactivation of the mPOA or rostral LH was ineffective. These findings indicate that hemorrhage activates neurons throughout much of the hypothalamus and that a relatively broad area of the hypothalamus, extending from the arcuate nucleus laterally through the caudal VMH and tuberal LH, plays an important role in the decompensatory phase of hemorrhage.
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Affiliation(s)
- G Göktalay
- Department of Medical Pharmacology, Uludag University, Faculty of Medicine, Bursa, Turkey
| | - W R Millington
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States.
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10
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TRPA1 channels mediate acute neurogenic inflammation and pain produced by bacterial endotoxins. Nat Commun 2015; 5:3125. [PMID: 24445575 PMCID: PMC3905718 DOI: 10.1038/ncomms4125] [Citation(s) in RCA: 315] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/16/2013] [Indexed: 02/07/2023] Open
Abstract
Gram-negative bacterial infections are accompanied by inflammation and somatic or visceral pain. These symptoms are generally attributed to sensitization of nociceptors by inflammatory mediators released by immune cells. Nociceptor sensitization during inflammation occurs through activation of the Toll-like receptor 4 (TLR4) signalling pathway by lipopolysaccharide (LPS), a toxic by-product of bacterial lysis. Here we show that LPS exerts fast, membrane delimited, excitatory actions via TRPA1, a transient receptor potential cation channel that is critical for transducing environmental irritant stimuli into nociceptor activity. Moreover, we find that pain and acute vascular reactions, including neurogenic inflammation (CGRP release) caused by LPS are primarily dependent on TRPA1 channel activation in nociceptive sensory neurons, and develop independently of TLR4 activation. The identification of TRPA1 as a molecular determinant of direct LPS effects on nociceptors offers new insights into the pathogenesis of pain and neurovascular responses during bacterial infections and opens novel avenues for their treatment. Gram-negative bacterial infections can often cause inflammation and pain. Meseguer et al. show that the inflammation and pain result from the direct activation of nociceptor TRPA1 channels by lipopolysaccharide, a major component of the outer membrane of Gram-negative bacteria.
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11
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The intracerebroventricular injection of rimonabant inhibits systemic lipopolysaccharide-induced lung inflammation. J Neuroimmunol 2015; 286:16-24. [PMID: 26298320 DOI: 10.1016/j.jneuroim.2015.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 06/22/2015] [Accepted: 07/01/2015] [Indexed: 01/23/2023]
Abstract
We investigated the role of intracerebroventricular (ICV) injection of rimonabant (500ng), a CB1 antagonist, on lipopolysaccharide ((LPS) 5mg/kg)-induced pulmonary inflammation in rats in an isolated perfused lung model. There were decreases in pulmonary capillary pressure (Ppc) and increases in the ((Wet-Dry)/Dry lung weight)/(Ppc) ratio in the ICV-vehicle/LPS group at 4h. There were decreases in TLR4 pathway markers, such as interleukin receptor-associated kinase-1, IκBα, Raf1 and phospho-SFK (Tyr416) at 30min and at 4h increases in IL-6, vascular cell adhesion molecule-1 and myeloperoxidase in lung homogenate. Intracerebroventricular rimonabant attenuated these LPS-induced responses, indicating that ICV rimonabant modulates LPS-initiated pulmonary inflammation.
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12
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Feleder C, Sertac Yilmaz M, Peng J, Göktalay G, Millington WR. The OVLT initiates the fall in arterial pressure evoked by high dose lipopolysaccharide: evidence that dichotomous, dose-related mechanisms mediate endotoxic hypotension. J Neuroimmunol 2015. [PMID: 26198924 DOI: 10.1016/j.jneuroim.2015.05.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study tested the hypothesis that lipopolysaccharide (LPS) lowers arterial pressure through two different mechanisms depending on the dose. Previously, we found that a low hypotensive dose of LPS (1mg/kg) lowers arterial pressure by activating vagus nerve afferents. Here we report that hypotension evoked by high dose LPS (15mg/kg) can be prevented by injecting lidocaine into the OVLT but not by vagotomy or inactivation of the NTS. The hypotension produced by both LPS doses was correlated with elevated extracellular norepinephrine concentrations in the POA and prevented by blocking alpha-adrenergic receptors. Thus, initiation of endotoxic hypotension is dose-related, mechanistically.
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Affiliation(s)
- Carlos Feleder
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, United States
| | - M Sertac Yilmaz
- Department of Medical Pharmacology, Uludag University, Faculty of Medicine, Bursa 16059, Turkey
| | - Jianya Peng
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, United States
| | - Gökhan Göktalay
- Department of Medical Pharmacology, Uludag University, Faculty of Medicine, Bursa 16059, Turkey
| | - William R Millington
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, United States.
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Daulatzai MA. Chronic functional bowel syndrome enhances gut-brain axis dysfunction, neuroinflammation, cognitive impairment, and vulnerability to dementia. Neurochem Res 2014; 39:624-44. [PMID: 24590859 DOI: 10.1007/s11064-014-1266-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/10/2014] [Accepted: 02/25/2014] [Indexed: 12/15/2022]
Abstract
The irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder world wide that lasts for decades. The human gut harbors a diverse population of microbial organisms which is symbiotic and important for well being. However, studies on conventional, germ-free, and obese animals have shown that alteration in normal commensal gut microbiota and an increase in pathogenic microbiota-termed "dysbiosis", impact gut function, homeostasis, and health. Diarrhea, constipation, visceral hypersensitivity, and abdominal pain arise in IBS from the gut-induced dysfunctional metabolic, immune, and neuro-immune communication. Dysbiosis in IBS is associated with gut inflammation. Gut-related inflammation is pivotal in promoting endotoxemia, systemic inflammation, and neuroinflammation. A significant proportion of IBS patients chronically consume alcohol, non-steroidal anti-inflammatories, and fatty diet; they may also suffer from co-morbid respiratory, neuromuscular, psychological, sleep, and neurological disorders. The above pathophysiological substrate is underpinned by dysbiosis, and dysfunctional bidirectional "Gut-Brain Axis" pathways. Pathogenic gut microbiota-related systemic inflammation (due to increased lipopolysaccharide and pro-inflammatory cytokines, and barrier dysfunction), may trigger neuroinflammation enhancing dysfunctional brain regions including hippocampus and cerebellum. These as well as dysfunctional vago-vagal gut-brain axis may promote cognitive impairment. Indeed, inflammation is characteristic of a broad spectrum of neurodegenerative diseases that manifest demntia. It is argued that an awareness of pathophysiological impact of IBS and implementation of appropriate therapeutic measures may prevent cognitive impairment and minimize vulnerability to dementia.
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Affiliation(s)
- Mak Adam Daulatzai
- Sleep Disorders Group, EEE Department, Melbourne School of Engineering, The University of Melbourne, Grattan Street, 3rd Floor, Room No. 344, Parkville, VIC, 3010, Australia,
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Zhang F, Wang D, Li X, Li Z, Chao J, Qin X. Metabolomic study of the fever model induced by baker's yeast and the antipyretic effects of aspirin in rats using nuclear magnetic resonance and gas chromatography-mass spectrometry. J Pharm Biomed Anal 2013; 81-82:168-77. [PMID: 23670098 DOI: 10.1016/j.jpba.2013.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/01/2013] [Accepted: 04/06/2013] [Indexed: 11/28/2022]
Abstract
A metabolomic investigation of baker's yeast-induced fever in rats was carried out. Plasma derived from Sprague-Dawley rats treated by subcutaneous administration of 20% (w/v) baker's yeast was analyzed using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). Statistical data analysis using t-test and orthogonal partial least-squares discriminant analysis revealed many significant changes in the metabolic data in the plasma of the fever group. Clear separation was achieved between the fever and control groups. Seventeen marked metabolites were found in the fever group. The metabolites, which include amino acids, carbohydrate, organic acids, and fatty acids, mostly contributed to the discrimination of plasma samples from the control and fever groups. These results suggested that fever may involve in the perturbation of amino acid metabolism coupled with energy metabolism, lipid metabolism, and glycometabolism. After determining the antipyretic effects of aspirin on the fever group, four metabolites in the fever rat plasma were found to be signally regulated and recognized as potential biomarkers, including 3-hydroxybutyric acid, gamma-aminobutyric acid, glucose, and linoleic acid. The metabolic relationships that possibly exist between these potential biomarkers were speculated, and the mechanism of baker's yeast-induced fever was illustrated based on the metabolic relationships. This study found that metabolomic approaches such as GC-MS and NMR could be used as potential powerful tools to investigate the biochemical changes and mechanisms in certain pathological states at the metabolism level.
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Affiliation(s)
- Fusheng Zhang
- Modern Research Center for Traditional Chinese Medicine of Shanxi University, No. 92, Wucheng Road, Taiyuan 030006, Shanxi, PR China
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Al-Saffar H, Lewis K, Liu E, Schober A, Corrigan JJ, Shibata K, Steiner AA. Lipopolysaccharide-induced hypothermia and hypotension are associated with inflammatory signaling that is triggered outside the brain. Brain Behav Immun 2013. [PMID: 23207106 DOI: 10.1016/j.bbi.2012.11.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Little is known about the neuroimmune mechanisms responsible for the switch from fever to hypothermia observed in severe forms of systemic inflammation. We evaluated whether bacterial lipopolysaccharide (LPS) acting directly on the brain could promote a fever-hypothermia switch as well as the hypotension that is often associated with hypothermia in models of systemic inflammation. At an ambient temperature of 22°C, freely moving rats received intracerebroventricular (i.c.v.) injections of LPS at doses ranging from 0.5 to 25μg. Despite the use of such high doses, the prevailing thermal response was fever. To investigate if a hypothermic response could be hidden within the prevailing febrile response, rats were pretreated with a cyclooxygenase-2 inhibitor (SC-236, 3.5mg/kg i.v.) known to block fever, but this strategy also failed to reveal any consistent hypothermic response following i.c.v. LPS. At the doses tested, i.c.v. LPS was similarly ineffective at inducing hypotension. Additional doses of LPS did not need to be tested because the 25-μg dose was already sufficient to induce both hypothermia and hypotension when administered peripherally (intra-arterially). An empirical 3D model of the interplay among body temperature, arterial pressure and heart rate following intra-arterial LPS reinforced the strong association of hypothermia with hypotension and, at the same time, exposed a bell-shaped relationship between heart rate and body temperature. In summary, the present study demonstrates that hypothermia and hypotension are triggered exclusively by LPS acting outside the brain and provides an integrated model of the thermal and cardiovascular responses to peripheral LPS.
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Affiliation(s)
- Hiba Al-Saffar
- Albany College of Pharmacy and Health Sciences, Albany, NY, USA
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Effects of lipopolysaccharide on the neuronal control of mesenteric vascular tone in rats: mechanisms involved. Shock 2012; 38:328-34. [PMID: 22744306 DOI: 10.1097/shk.0b013e31826240ba] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The aim of the present study was to investigate the effects of lipopolysaccharide (LPS) on the contractile response induced by electrical field stimulation (EFS) in rat mesenteric segments, as well as the mechanisms involved. Effects of LPS incubation for 2 or 5 h were studied in mesenteric segments from male Wistar rats. Vasomotor responses to EFS, nitric oxide (NO) donor DEA-NO, and noradrenaline (NA) were studied. Phosphorylated neuronal NO synthase protein expression was analyzed, and NO, superoxide anion (O2·), and peroxynitrite releases were also determined. Lipopolysaccharide increased EFS-induced vasoconstriction at 2 h. This increase was lower after 5-h preincubation. N-nitro-L-arginine methyl ester increased vasoconstrictor response only in control segments. Vasodilator response to DEA-NO was increased by LPS after 5-h preincubation and was decreased by O2· scavenger tempol. Basal NO release was increased by LPS. Electrical field stimulation-induced NO release was reduced by LPS compared with control conditions. Lipopolysaccharide exposure increased both O2· and peroxynitrite release. Vasoconstriction to exogenous NA was markedly increased by LPS compared with control conditions after 2-h incubation and remained unchanged after 5-h incubation. Short-term exposure of rat mesenteric arteries to LPS produced a time-dependent enhanced contractile response to EFS. The early phase (2 h) was associated to a reduction in NO from neuronal NO synthase and an enhanced response to NA. After 5 h of LPS exposure, this enhancement was reduced, because of restoration of the adrenergic component and maintenance of the nitrergic reduction.
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Dysfunctional nucleus tractus solitarius: its crucial role in promoting neuropathogenetic cascade of Alzheimer's dementia--a novel hypothesis. Neurochem Res 2012; 37:846-68. [PMID: 22219130 DOI: 10.1007/s11064-011-0680-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/16/2011] [Accepted: 12/15/2011] [Indexed: 12/22/2022]
Abstract
The pathophysiological mechanism(s) underlying Alzheimer's disease (AD) still remain unclear, and no disease-modifying or prophylactic therapies are currently available. Unraveling the fundamental neuropathogenesis of AD is an important challenge. Several studies on AD have suggested lesions in a number of CNS areas including the basal forebrain, hippocampus, entorhinal cortex, amygdale/insula, and the locus coeruleus. However, plausible unifying studies on the upstream factors that involve these heterogeneous regions and herald the onset of AD pathogenesis are not available. The current article presents a novel nucleus tractus solitarius (NTS) vector hypothesis that underpins several disparate biological mechanisms and neural circuits, and identifies relevant hallmarks of major presumptive causative factor(s) linked to the NTS, in older/aging individuals. Aging, obesity, infection, sleep apnea, smoking, neuropsychological states, and hypothermia-all activate inflammatory cytokines and oxidative stress. The synergistic impact of systemic proinflammatory mediators activates microglia and promotes neuroinflammation. Acutely, the innate immune response is protective defending against pathogens/toxins; however, when chronic, it causes neuroinflammation and neuronal dysfunction, particularly in brainstem and neocortex. The NTS in the brainstem is an essential multiple signaling hub, and an extremely important central integration site of baroreceptor, chemoreceptor, and a multitude of sensory afferents from gustatory, gastrointestinal, cardiac, pulmonary, and upper airway systems. Owing to persistent neuroinflammation, the dysfunctional NTS exerts deleterious impact on nucleus ambiguus, dorsal motor nucleus of vagus, hypoglossal, parabrachial, locus coeruleus and many key nuclei in the brainstem, and the hippocampus, entorhinal cortex, prefrontal cortex, amygdala, insula, and basal forebrain in the neocortex. The neuronal and synaptic dysfunction emanating from the inflamed NTS may affect its interconnected pathways impacting almost the entire CNS--which is already primed by neuroinflammation, thus promoting cognitive and neuropsychiatric symptoms. The upstream factors discussed here may underpin the neuropathopgenesis of AD. AD pathology is multifactorial; the current perspective underscores the value of attenuating disparate upstream factors--in conjunction with anticholinesterase, anti-inflammatory, immunosuppressive, and anti-oxidant pharmacotherapy. Amelioration of the NTS pathology may be of central importance in countering the neuropathological cascade of AD. The NTS, therefore, may be a potential target of novel therapeutic strategies.
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Romanovsky AA, Garami A. Prostaglandin riddles in energy metabolism: E is for excess, D is for depletion. Focus on "Food deprivation alters thermoregulatory responses to lipopolysaccharide by enhancing cryogenic inflammatory signaling via prostaglandin D2". Am J Physiol Regul Integr Comp Physiol 2010; 298:R1509-11. [PMID: 20410482 DOI: 10.1152/ajpregu.00253.2010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Central cannabinoid 1 receptor antagonist administration prevents endotoxic hypotension affecting norepinephrine release in the preoptic anterior hypothalamic area. Shock 2010; 32:614-20. [PMID: 19295473 DOI: 10.1097/shk.0b013e3181a4fd8f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
It is widely assumed that LPS lowers arterial pressure during sepsis by stimulating release of TNF-alpha and other vasoactive mediators from macrophages. However, recent data from this and other laboratories have shown that LPS hypotension can be prevented by inhibiting afferent impulse flow in the vagus nerve, by blocking neuronal activity in the nucleus of the solitary tract, or by blocking alpha-adrenergic receptors in the preoptic area/anterior hypothalamic area (POA). These findings suggest that the inflammatory signal is conveyed from the periphery to the brain via the vagus nerve, and that endotoxic shock is mediated through a central mechanism that requires activation of POA neurons. In the present study, we tested whether central cannabinoid 1 (CB1) receptors participate in the control of arterial pressure during endotoxemia based on evidence that hypothalamic neurons express CB1 receptors and synthesize the endogenous CB anandamide. We found that intracerebroventricular administration of rimonabant, a CB1 receptor antagonist, inhibited the fall in arterial pressure evoked by LPS significantly in both conscious and anesthetized rats. Rimonabant attenuated both the immediate fall in arterial pressure evoked by LPS and the second, delayed hypotensive phase that leads to tissue ischemia and death. Rimonabant also prevented the associated LPS-induced rise in extracellular fluid norepinephrine concentrations in the POA. Furthermore, rimonabant attenuated the associated increase in plasma TNF-alpha concentrations characteristic of the late phase of endotoxic hypotension. These data indicate that central CB1 receptors may play an important role in the initiation of endotoxic hypotension.
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