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Bacle A, Kadri L, Khoury S, Ferru-Clément R, Faivre JF, Cognard C, Bescond J, Krzesiak A, Contzler H, Delpech N, Colas J, Vandebrouck C, Sébille S, Ferreira T. A comprehensive study of phospholipid fatty acid rearrangements in metabolic syndrome: correlations with organ dysfunction. Dis Model Mech 2020; 13:dmm043927. [PMID: 32303571 PMCID: PMC7328154 DOI: 10.1242/dmm.043927] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/07/2020] [Indexed: 12/17/2022] Open
Abstract
The balance within phospholipids (PLs) between saturated fatty acids and monounsaturated or polyunsaturated fatty acids is known to regulate the biophysical properties of cellular membranes. As a consequence, in many cell types, perturbing this balance alters crucial cellular processes, such as vesicular budding and the trafficking/function of membrane-anchored proteins. The worldwide spread of the Western diet, which is highly enriched in saturated fats, has been clearly correlated with the emergence of a complex syndrome known as metabolic syndrome (MetS). MetS is defined as a cluster of risk factors for cardiovascular diseases, type 2 diabetes and hepatic steatosis; however, no clear correlations have been established between diet-induced fatty acid redistribution within cellular PLs and the severity/chronology of the symptoms associated with MetS or the function of the targeted organs. To address this issue, in this study we analyzed PL remodeling in rats exposed to a high-fat/high-fructose diet (HFHF) over a 15-week period. PL remodeling was analyzed in several organs, including known MetS targets. We show that fatty acids from the diet can redistribute within PLs in a very selective manner, with phosphatidylcholine being the preferred sink for this redistribution. Moreover, in the HFHF rat model, most organs are protected from this redistribution, at least during the early onset of MetS, at the expense of the liver and skeletal muscles. Interestingly, such a redistribution correlates with clear-cut alterations in the function of these organs.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Amélie Bacle
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Linette Kadri
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Spiro Khoury
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Romain Ferru-Clément
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Jean-François Faivre
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Christian Cognard
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Jocelyn Bescond
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Amandine Krzesiak
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Hugo Contzler
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Nathalie Delpech
- Laboratoire "Mobilité Vieillissement et Exercice (MOVE; EA 6314)", Université de Poitiers, 8, Allée Jean Monnet, 86073 Poitiers, France
| | - Jenny Colas
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Clarisse Vandebrouck
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Stéphane Sébille
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
- Laboratoire "Signalisation et Transports Ioniques Membranaires (STIM; EA 7349)", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
| | - Thierry Ferreira
- Laboratoire "Lipotoxicity and Channelopathies (LitCh) - ConicMeds", Université de Poitiers, 1, rue Georges Bonnet, 86073 Poitiers, France
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Norez C, Jayle C, Becq F, Vandebrouck C. Bronchorelaxation of the human bronchi by CFTR activators. Pulm Pharmacol Ther 2013; 27:38-43. [PMID: 23827485 DOI: 10.1016/j.pupt.2013.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 06/18/2013] [Accepted: 06/21/2013] [Indexed: 11/19/2022]
Abstract
The airway functions are profoundly affected in many diseases including asthma, COPD and cystic fibrosis (CF). CF the most common lethal autosomal recessive genetic disease is caused by mutations of the CFTR (Cystic Fibrosis transmembrane Conductance Regulator) gene, which normally encodes a multifunctional and integral membrane cAMP regulated and ATP gated Cl(-) channel expressed in airway epithelial cells. Using human lung tissues obtained from patients undergoing surgery for lung cancer, we demonstrated that CFTR participates in bronchorelaxation. Using human bronchial smooth muscle cells (HBSMC), we applied iodide influx assay to analyze the CFTR-dependent ionic transport and immunofluorescence technique to localize CFTR proteins. Moreover, the relaxation was studied in isolated human bronchial segments after pre-contraction with carbachol to determine the implication of CFTR in bronchodilation. We found in HBSMC that the pharmacology and regulation of CFTR is similar to that of its epithelial counterpart both for activation (using forskolin/genistein or a benzo[c]quinolizinium derivative) and for inhibition (CFTR(inh)-172 and GPinh5a). With human bronchial rings, we observed that whatever the compound used including salbutamol, the activation of muscular CFTR leads to a bronchodilation after constriction with carbachol. Altogether, these observations revealed that CFTR in the human airways is expressed in bronchial smooth muscle cells and can be pharmacologically manipulated leading to the hypothesis that this ionic channel could contribute to bronchodilation in human.
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Affiliation(s)
- Caroline Norez
- Institut de Physiologie et Biologie Cellulaires CNRS FRE3511, Université de Poitiers, Poitiers, France
| | - Christophe Jayle
- Service de chirurgie cardiothoracique, CHU La Milétrie, Poitiers, France
| | - Frédéric Becq
- Institut de Physiologie et Biologie Cellulaires CNRS FRE3511, Université de Poitiers, Poitiers, France
| | - Clarisse Vandebrouck
- Institut de Physiologie et Biologie Cellulaires CNRS FRE3511, Université de Poitiers, Poitiers, France.
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Vanhoutte PM. Airway epithelium-derived relaxing factor: myth, reality, or naivety? Am J Physiol Cell Physiol 2013; 304:C813-20. [PMID: 23325407 DOI: 10.1152/ajpcell.00013.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The presence of a healthy epithelium can moderate the contraction of the underlying airway smooth muscle. This is, in part, because epithelial cells generate inhibitory messages, whether diffusible substances, electrophysiological signals, or both. The epithelium-dependent inhibitory effect can be tonic (basal), synergistic, or evoked. Rather than a unique epithelium-derived relaxing factor (EpDRF), several known endogenous bronchoactive mediators, including nitric oxide and prostaglandin E2, contribute. The early concept that EpDRF diffuses all the way through the subepithelial layers to directly relax the airway smooth muscle appears unlikely. It is more plausible that the epithelial cells release true messenger molecules, which alter the production of endogenous substances (nitric oxide and/or metabolites of arachidonic acid) by the subepithelial layers. These substances then diffuse to the airway smooth muscle cells, conveying epithelium dependency.
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Affiliation(s)
- Paul M Vanhoutte
- Department of Pharmacology and Pharmacy, University of Hong Kong, Hong Kong, China.
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Qu F, Qin XQ, Cui YR, Xiang Y, Tan YR, Liu HJ, Peng LH, Zhou XY, Liu C, Zhu XL. Ozone stress down-regulates the expression of cystic fibrosis transmembrane conductance regulator in human bronchial epithelial cells. Chem Biol Interact 2009; 179:219-26. [DOI: 10.1016/j.cbi.2008.10.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 10/29/2008] [Accepted: 10/31/2008] [Indexed: 10/21/2022]
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Jing Y, Dowdy JA, Van Scott MR, Fedan JS. Simultaneous measurement of mechanical responses and transepithelial potential difference and resistance, in guinea-pig isolated, perfused trachea using a novel apparatus: Pharmacological characterization. Eur J Pharmacol 2008; 598:98-103. [DOI: 10.1016/j.ejphar.2008.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 08/28/2008] [Accepted: 09/09/2008] [Indexed: 11/28/2022]
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Ruan YC, Wang Z, Du JY, Zuo WL, Guo JH, Zhang J, Wu ZL, Wong HY, Chung YW, Chan HC, Zhou WL. Regulation of smooth muscle contractility by the epithelium in rat vas deferens: role of ATP-induced release of PGE2. J Physiol 2008; 586:4843-57. [PMID: 18755753 DOI: 10.1113/jphysiol.2008.154096] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Recent studies suggest that the epithelium might modulate the contractility of smooth muscle. However, the mechanisms underlying this regulation are unknown. The present study investigated the regulation of smooth muscle contraction by the epithelium in rat vas deferens and the possible factor(s) involved. Exogenously applied ATP inhibited electrical field stimulation (EFS)-evoked smooth muscle contraction in an epithelium-dependent manner. As the effects of ATP on smooth muscle contractility were abrogated by inhibitors of prostaglandin synthesis, but not by those of nitric oxide synthesis, prostaglandins might mediate the effects of ATP. Consistent with this idea, PGE(2) inhibited EFS-evoked smooth muscle contraction independent of the epithelium, while ATP and UTP induced the release of PGE(2) from cultured rat vas deferens epithelial cells, but not smooth muscle cells. The ATP-induced PGE(2) release from vas deferens epithelial cells was abolished by U73122, an inhibitor of phospholipase C (PLC) and BAPTA AM, a Ca(2+) chelator. ATP also transiently increased [Ca(2+)](i) in vas deferens epithelial cells. This effect of ATP on [Ca(2+)](i) was independent of extracellular Ca(2+), but abolished by the P2 receptor antagonist RB2 and U73122. In membrane potential measurements using a voltage-sensitive dye, PGE(2), but not ATP, hyperpolarized vas deferens smooth muscle cells and this effect of PGE(2) was blocked by MDL12330A, an adenylate cyclase inhibitor, and the chromanol 293B, a blocker of cAMP-dependent K(+) channels. Taken together, our results suggest that ATP inhibition of vas deferens smooth muscle contraction is epithelium dependent. The data also suggest that ATP activates P2Y receptor-coupled Ca(2+) mobilization leading to the release of PGE(2) from epithelial cells, which in turn activates cAMP-dependent K(+) channels in smooth muscle cells leading to the hyperpolarization of membrane voltage and the inhibition of vas deferens contraction. Thus, the present findings suggest a novel regulatory mechanism by which the epithelium regulates the contractility of smooth muscle.
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Affiliation(s)
- Ye Chun Ruan
- School of Life Science, Sun Yat-sen University, Guangzhou 510275, China
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Michoud MC, Robert R, Hassan M, Moynihan B, Haston C, Govindaraju V, Ferraro P, Hanrahan JW, Martin JG. Role of the cystic fibrosis transmembrane conductance channel in human airway smooth muscle. Am J Respir Cell Mol Biol 2008; 40:217-22. [PMID: 18757309 DOI: 10.1165/rcmb.2006-0444oc] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Patients with cystic fibrosis (CF) suffer from asthma-like symptoms and gastrointestinal cramps, attributed to a mutation in the CF transmembrane conductance regulator (CFTR) gene present in a variety of cells. Pulmonary manifestations of the disease include the production of thickened mucus and symptoms of asthma, such as cough and wheezing. A possible alteration in airway smooth muscle (ASM) cell function of patients with CF has not been investigated. The aim of this study was to determine whether the (CFTR) channel is present and affects function of human ASM cells. Cell cultures were obtained from the main or lobar bronchi of patients with and without CF, and the presence of the CFTR channel detected by immunofluorescence. Cytosolic Ca(2+) was measured using Fura-2 and dual-wavelength microfluorimetry. The results show that CFTR is expressed in airway bronchial tissue and in cultured ASM cells. Peak Ca(2+) release in response to histamine was significantly decreased in CF cells compared with non-CF ASM cells (357 +/- 53 nM versus 558 +/- 20 nM; P < 0.001). The CFTR pharmacological blockers, glibenclamide and N-phenyl anthranilic acid, significantly reduced histamine-induced Ca(2+) release in non-CF cells, and similar results were obtained when CFTR expression was varied using antisense oligonucleotides. In conclusion, these data show that the CFTR channel is present in ASM cells, and that it modulates the release of Ca(2+) in response to contractile agents. In patients with CF, a dysfunctional CFTR channel could contribute to the asthma diathesis and gastrointestinal problems experienced by these patients.
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Affiliation(s)
- Marie-Claire Michoud
- Meakins Christie Laboratories, Department of Medicine, McGill University, 3626 St. Urbain, Montreal, PQ, H2X 2P2 Canada
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Vandebrouck C, Melin P, Norez C, Robert R, Guibert C, Mettey Y, Becq F. Evidence that CFTR is expressed in rat tracheal smooth muscle cells and contributes to bronchodilation. Respir Res 2006; 7:113. [PMID: 16938132 PMCID: PMC1560124 DOI: 10.1186/1465-9921-7-113] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Accepted: 08/28/2006] [Indexed: 11/29/2022] Open
Abstract
Background The airway functions are profoundly affected in many diseases including asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). CF the most common lethal autosomal recessive genetic disease is caused by mutations of the CFTR gene, which normally encodes a multifunctional and integral membrane protein, the CF transmembrane conductance regulator (CFTR) expressed in airway epithelial cells. Methods To demonstrate that CFTR is also expressed in tracheal smooth muscle cells (TSMC), we used iodide efflux assay to analyse the chloride transports in organ culture of rat TSMC, immunofluorescence study to localize CFTR proteins and isometric contraction measurement on isolated tracheal rings to observe the implication of CFTR in the bronchodilation. Results We characterized three different pathways stimulated by the cAMP agonist forskolin and the isoflavone agent genistein, by the calcium ionophore A23187 and by hypo-osmotic challenge. The pharmacology of the cAMP-dependent iodide efflux was investigated in detail. We demonstrated in rat TSMC that it is remarkably similar to that of the epithelial CFTR, both for activation (using three benzo [c]quinolizinium derivatives) and for inhibition (glibenclamide, DPC and CFTRinh-172). Using rat tracheal rings, we observed that the activation of CFTR by benzoquinolizinium derivatives in TSMC leads to CFTRinh-172-sensitive bronchodilation after constriction with carbachol. An immunolocalisation study confirmed expression of CFTR in tracheal myocytes. Conclusion Altogether, these observations revealed that CFTR in the airways of rat is expressed not only in the epithelial cells but also in tracheal smooth muscle cells leading to the hypothesis that this ionic channel could contribute to bronchodilation.
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Affiliation(s)
- Clarisse Vandebrouck
- Institut de Physiologie et Biologie Cellulaires CNRS UMR 6187, Université de Poitiers, 40 Avenue du Recteur Pineau 86022 Poitiers, Cedex, France
| | - Patricia Melin
- Institut de Physiologie et Biologie Cellulaires CNRS UMR 6187, Université de Poitiers, 40 Avenue du Recteur Pineau 86022 Poitiers, Cedex, France
| | - Caroline Norez
- Institut de Physiologie et Biologie Cellulaires CNRS UMR 6187, Université de Poitiers, 40 Avenue du Recteur Pineau 86022 Poitiers, Cedex, France
| | - Renaud Robert
- Institut de Physiologie et Biologie Cellulaires CNRS UMR 6187, Université de Poitiers, 40 Avenue du Recteur Pineau 86022 Poitiers, Cedex, France
| | - Christelle Guibert
- Laboratoire de Physiologie Cellulaire Respiratoire INSERM 0356 Université Victor Segalen Bordeaux2, 146, rue Léo Saignat, 33076 Bordeaux, Cedex, France
| | - Yvette Mettey
- Institut de Physiologie et Biologie Cellulaires CNRS UMR 6187, Université de Poitiers, 40 Avenue du Recteur Pineau 86022 Poitiers, Cedex, France
| | - Frédéric Becq
- Institut de Physiologie et Biologie Cellulaires CNRS UMR 6187, Université de Poitiers, 40 Avenue du Recteur Pineau 86022 Poitiers, Cedex, France
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Ong HL, Barritt GJ. Transient receptor potential and other ion channels as pharmaceutical targets in airway smooth muscle cells. Respirology 2005; 9:448-57. [PMID: 15612955 DOI: 10.1111/j.1440-1843.2004.00651.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Regardless of the triggering stimulus in asthma, contraction of the airway smooth muscle (ASM) is considered to be an important pathway leading to the manifestation of asthmatic symptoms. Therefore, the various ion channels that modulate ASM contraction and relaxation are particularly attractive targets for therapy. Although voltage-operated Ca2+ channels (VOCC) are the most extensively characterised Ca(2+)-permeable channels in ASM cells and are obvious pharmacological targets, blockers of VOCC have not been successful in alleviating ASM contraction in asthma. Similarly, although the Cl- and K+ channels also modulate ASM contraction and relaxation by regulating plasma membrane potential, pharmacological interventions directed against these channels have failed to abrogate ASM contraction in asthma. A large body of evidence suggests that store-operated Ca2+ channels (SOCC) and Ca(2+)-permeable second messenger-activated non-selective cation channels (NSCC) predominantly mediate ASM contraction. However, development of pharmacological interventions involving these channels has been hampered by the paucity of information regarding their molecular identity. Members of the mammalian transient receptor potential (TRP) protein family, which form voltage-independent channels with variable Ca2+ selectivity that are activated by store depletion and/or by intracellular messengers, are potential molecular candidates for SOCC and NSCC in ASM cells. While the function of TRP channels in ASM cells remains to be elucidated and there are, at present, essentially no good TRP channel antagonists, this group of proteins is a potentially valuable pharmaceutical target for the treatment of asthma.
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Affiliation(s)
- Hwei L Ong
- Department of Medical Biochemistry, School of Medicine, Flinders University, Adelaide, South Australia, Australia
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Chignard N, Mergey M, Veissière D, Poupon R, Capeau J, Parc R, Paul A, Housset C. Bile salts potentiate adenylyl cyclase activity and cAMP-regulated secretion in human gallbladder epithelium. Am J Physiol Gastrointest Liver Physiol 2003; 284:G205-12. [PMID: 12421748 DOI: 10.1152/ajpgi.00292.2002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fluid and ion secretion in the gallbladder is mainly triggered by the intracellular second messenger cAMP. We examined the action of bile salts on the cAMP-dependent pathway in the gallbladder epithelium. Primary cultures of human gallbladder epithelial cells were exposed to agonists of the cAMP pathway and/or to bile salts. Taurochenodeoxycholate and tauroursodeoxycholate increased forskolin-induced cAMP accumulation to a similar extent, without affecting cAMP basal levels. This potentiating effect was abrogated after PKC inhibition, whereas both taurochenodeoxycholate and tauroursodeoxycholate induced PKC-alpha and -delta translocation to cell membranes. Consistent with a PKC-mediated stimulation of cAMP production, the expression of six adenylyl cyclase isoforms, including PKC-regulated isoforms 5 and 7, was identified in human gallbladder epithelial cells. cAMP-dependent chloride secretion induced by isoproterenol, a beta-adrenergic agonist, was significantly increased by taurochenodeoxycholate and by tauroursodeoxycholate. In conclusion, endogenous and therapeutic bile salts via PKC regulation of adenylyl cyclase activity potentiate cAMP production in the human gallbladder epithelium. Through this action, bile salts may increase fluid secretion in the gallbladder after feeding.
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Affiliation(s)
- Nicolas Chignard
- Institut National de la Santé et de la Recherche Médicale, Hôpital Saint-Antoine, 75012 Paris, France
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Parai K, Tabrizchi R. A comparative study of the effects of Cl(-) channel blockers on mesenteric vascular conductance in anaesthetized rat. Eur J Pharmacol 2002; 448:59-66. [PMID: 12126972 DOI: 10.1016/s0014-2999(02)01895-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is evidence to suggest that niflumic acid is capable of selectively inhibiting Ca(2+)-dependent Cl(-) channels. Furthermore, it has been demonstrated that niflumic acid is capable of antagonizing contractile responses due to activation of alpha(1)-adrenoceptor in mesenteric vasculature. Here, we have examined the effects of three Cl(-) channel blockers, niflumic acid, indanyloxyacetic acid 94 (IAA-94) and diphenylamine-2-carboxylic acid (DPC) on cirazoline-mediated vasoconstriction in mesenteric blood vessel in vivo. Infusion of cirazoline produced a dose-dependent increase in blood pressure, decrease in superior mesenteric blood flow, mesenteric vascular conductance and heart rate. While niflumic acid and IAA-94 did not have any impact on cirazoline-induced changes in blood pressure, DPC accentuated the pressor effect of cirazoline. Neither agent affected cirazoline-mediated reflex reduction in the heart rate. Niflumic acid, IAA-94 and DPC attenuated alpha(1)-adrenoceptor mediated decrease in mesenteric blood flow and vascular conductance. Based on the profile of the actions of these compounds, it may be suggested that IAA-94 did not appear to act as selective inhibitor of Ca(2+)-activated Cl(-) channels when compared to niflumic acid in the mesenteric blood vessels. In addition, while DPC seems to be as effective as niflumic acid in its effects on mesenteric blood vessels, its actions may be attributed to other pharmacological effects.
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Affiliation(s)
- Kakoli Parai
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, Health Sciences Centre, St. John's NF, Canada A1B 3V6
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