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Zeng R, Liu B, Guo T, Guo J, Yu G, Xu Y, Lin R, Tan X, Xie K, Zhou Y. Prostaglandin F 2α evokes vasoconstrictor and vasodepressor activities that are both independent of the F prostanoid receptor. FASEB J 2022; 36:e22293. [PMID: 35349198 DOI: 10.1096/fj.202101908r] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/09/2022] [Accepted: 03/20/2022] [Indexed: 02/05/2023]
Abstract
The F prostanoid receptor (FP), which accounts for the therapeutic effect of PGF2α in uterine atony that leads to postpartum hemorrhage and maternal morbidity, could possibly mediate vasoconstrictor effect in small or resistance arteries to elevate blood pressure that limits the clinical use of the agent in patients with cardiovascular disorders. This study aimed to test the above hypothesis with genetically altered mice. Ex vivo and in vivo experiments were performed on control wild-type (WT) mice and mice with deficiencies in FP (FP-/- ) or thromboxane (Tx)-prostanoid receptor (the original receptor of TxA2 ; TP-/- ), and/or those with an additional deficiency in E prostanoid receptor-3 (one of the vasoconstrictor receptors of PGE2 ; EP3-/- ). Here, we show that PGF2α indeed evoked vasoconstrictor responses in the above-mentioned tissues of WT mice, which were however unaltered by FP-/- . Interestingly, such contractile responses were reversed into dilations by TP-/- /EP3-/- . A similar pattern of results was observed with the pressor effect of PGF2α under in vivo conditions. However, TP-/- alone (which could largely remove the contractile responses) did not result in relaxation to PGF2α . Also, either the ex vivo vasodilator effect or the in vivo depressor response of PGF2α obtained after the removal of TP and EP3-mediated actions was unaltered by FP-/- . Therefore, both the ex vivo vasoconstrictor action in small or resistance arteries and the systemic pressor effect of PGF2α can reflect vasoconstrictor activities derived from the non-FP receptors TP and EP3 outweighing a concurrently activated dilator effect, which is again independent of FP.
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Affiliation(s)
- Ruhui Zeng
- Department of Gynaecology and Obstetrics, First Affiliated Hospital, Shantou University Medical College, Shantou, China
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
| | - Bin Liu
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, China
| | - Tingting Guo
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
| | - Jinwei Guo
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, China
| | - Gang Yu
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
| | - Yineng Xu
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
| | - Rui Lin
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
| | - Xiangzhai Tan
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
| | - Kaiqi Xie
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, China
| | - Yingbi Zhou
- Cardiovascular Research Center, Shantou University Medical College, Shantou, China
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Shen L, Patel JA, Norel X, Moledina S, Whittle BJ, von Kessler K, Sista P, Clapp LH. Pharmacology of the single isomer, esuberaprost (beraprost-314d) on pulmonary vascular tone, IP receptors and human smooth muscle proliferation in pulmonary hypertension. Biochem Pharmacol 2019; 166:242-252. [DOI: 10.1016/j.bcp.2019.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/29/2019] [Indexed: 12/20/2022]
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Abstract
Vascular myography is an in vitro technique used to examine functional responses of isolated blood vessels. This classical pharmacological technique has been in use for over a century. The assay technique studies changes in isometric tone of large and small vessels, arteries and veins, and tissues from genetic or disease models. This chapter describes the apparatus required, tissue collection methods, and the mounting of the tissues in the chambers of both large organ baths and the small vessel myograph. Considerations of the experimental conditions and design are discussed as well as the analysis of the collected data.
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Benyahia C, Ozen G, Orie N, Ledwozyw A, Louedec L, Li F, Senbel AM, Silverstein A, Danel C, Longrois D, Clapp LH, Norel X, Topal G. Ex vivo relaxations of pulmonary arteries induced by prostacyclin mimetics are highly dependent of the precontractile agents. Prostaglandins Other Lipid Mediat 2015; 121:46-52. [PMID: 26362969 DOI: 10.1016/j.prostaglandins.2015.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 08/18/2015] [Accepted: 09/04/2015] [Indexed: 01/08/2023]
Abstract
Prostacyclin (PGI2) mimetics (iloprost, treprostinil) are potent vasodilators (primarily via IP-receptor activation) and major therapeutic interventions for pulmonary hypertension (PH). Increased plasma levels of endothelin (ET-1), thromboxane (TxA2) and catecholamines have been demonstrated from patients with PH. In this study, we aimed to compare relaxant effects of iloprost and treprostinil on human (HPA) and rat pulmonary arteries precontracted with either ET-1, thromboxane (U46619) or an α-adrenergic receptor agonist (Norepinephrine, NE or phenylephrine, PE). Treprostinil and iloprost induced vasorelaxation of HPA precontracted with NE, ET-1 or U46619. We obtained greater relaxation response and sensitivity to treprostinil when ET-1 or U46619 were used to induce the precontraction in comparison to NE. In contrast, iloprost showed less relaxation response and sensitivity in HPA precontracted with U46619 versus NE. In the rat, treprostinil and iloprost induced vasorelaxation of pulmonary arteries precontracted with PE and U46619 but minimally with ET-1. However, in rat pulmonary arteries, PE-induced precontractions were comparatively low amplitude. Our study showed that the ex vivo relaxation or sensitivity of pulmonary arteries induced by PGI2 mimetics is highly dependent on both the pre-contraction agent and the species. To best extrapolate to effects on human tissue, our results suggest that U46619 is the appropriate contractile agent for assessing the relaxant effect of PGI2 mimetics in rat pulmonary arteries. Finally we suggest that in PH patients with high plasma concentration of TxA2, treprostinil (not iloprost) would be a preferential treatment. On the other hand, if the ET-1 plasmatic level is high, either treprostinil or iloprost will be effective.
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Affiliation(s)
- Chabha Benyahia
- INSERM U1148, CHU X. Bichat, 46 rue H. Huchard, F-75018 Paris, France; Paris Nord University, Sorbonne Paris Cité, UMR-S1148, Paris F-75018, France
| | - Gulsev Ozen
- INSERM U1148, CHU X. Bichat, 46 rue H. Huchard, F-75018 Paris, France; Istanbul University, Faculty of Pharmacy, Department of Pharmacology, Beyazit, 34116 Istanbul, Turkey
| | | | - Agatha Ledwozyw
- Department of Medicine, University College London, London WC1E 6JF, UK
| | - Liliane Louedec
- INSERM U1148, CHU X. Bichat, 46 rue H. Huchard, F-75018 Paris, France
| | - Fangfang Li
- INSERM U1148, CHU X. Bichat, 46 rue H. Huchard, F-75018 Paris, France; Paris Descartes University, Sorbonne Paris Cité, UMR-S1148, Paris F-75018, France
| | - Amira M Senbel
- Alexandria University, Faculty of Pharmacy, Department of Pharmacology and Toxicology, Alexandria, Egypt
| | | | - Claire Danel
- CHU X. Bichat, Assistance Publique-Hôpitaux de Paris, Paris Diderot University, Sorbonne Paris Cité, UMR-1148, Paris F-75018, France
| | - Dan Longrois
- INSERM U1148, CHU X. Bichat, 46 rue H. Huchard, F-75018 Paris, France; Paris Nord University, Sorbonne Paris Cité, UMR-S1148, Paris F-75018, France; CHU X. Bichat, Assistance Publique-Hôpitaux de Paris, Paris Diderot University, Sorbonne Paris Cité, UMR-1148, Paris F-75018, France
| | - Lucie H Clapp
- Department of Medicine, University College London, London WC1E 6JF, UK
| | - Xavier Norel
- INSERM U1148, CHU X. Bichat, 46 rue H. Huchard, F-75018 Paris, France; Paris Nord University, Sorbonne Paris Cité, UMR-S1148, Paris F-75018, France.
| | - Gökçe Topal
- Istanbul University, Faculty of Pharmacy, Department of Pharmacology, Beyazit, 34116 Istanbul, Turkey
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Clapp LH, Gurung R. The mechanistic basis of prostacyclin and its stable analogues in pulmonary arterial hypertension: Role of membrane versus nuclear receptors. Prostaglandins Other Lipid Mediat 2015; 120:56-71. [PMID: 25917921 DOI: 10.1016/j.prostaglandins.2015.04.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 04/13/2015] [Indexed: 12/22/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a progressive disease of distal pulmonary arteries in which patients suffer from elevated pulmonary arterial pressure, extensive vascular remodelling and right ventricular failure. To date prostacyclin (PGI2) therapy remains the most efficacious treatment for PAH and is the only approved monotherapy to have a positive impact on long-term survival. A key thing to note is that improvement exceeds that predicted from vasodilator testing strongly suggesting that additional mechanisms contribute to the therapeutic benefit of prostacyclins in PAH. Given these agents have potent antiproliferative, anti-inflammatory and endothelial regenerating properties suggests therapeutic benefit might result from a slowing, stabilization or even some reversal of vascular remodelling in vivo. This review discusses evidence that the pharmacology of each prostacyclin (IP) receptor agonist so far developed is distinct, with non-IP receptor targets clearly contributing to the therapeutic and side effect profile of PGI2 (EP3), iloprost (EP1), treprostinil (EP2, DP1) along with a family of nuclear receptors known as peroxisome proliferator-activated receptors (PPARs), to which PGI2 and some analogues directly bind. These targets are functionally expressed to varying degrees in arteries, veins, platelets, fibroblasts and inflammatory cells and are likely to be involved in the biological actions of prostacylins. Recently, a highly selective IP agonist, selexipag has been developed for PAH. This agent should prove useful in distinguishing IP from other prostanoid receptors or PPAR binding effects in human tissue. It remains to be determined whether selectivity for the IP receptor gives rise to a superior or inferior clinical benefit in PAH.
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Affiliation(s)
- Lucie H Clapp
- Department of Medicine, UCL, Rayne Building, London WC1E 6JF, UK.
| | - Rijan Gurung
- Department of Medicine, UCL, Rayne Building, London WC1E 6JF, UK
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Pantazaka E, Taylor EJA, Bernard WG, Taylor CW. Ca(2+) signals evoked by histamine H1 receptors are attenuated by activation of prostaglandin EP2 and EP4 receptors in human aortic smooth muscle cells. Br J Pharmacol 2014; 169:1624-34. [PMID: 23638853 PMCID: PMC3724117 DOI: 10.1111/bph.12239] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/19/2013] [Accepted: 04/25/2013] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Histamine and prostaglandin E2 (PGE2 ), directly and via their effects on other cells, regulate the behaviour of vascular smooth muscle (VSM), but their effects on human VSM are incompletely resolved. EXPERIMENTAL APPROACH The effects of PGE2 on histamine-evoked changes in intracellular free Ca(2+) concentration ([Ca(2+) ]i ) and adenylyl cyclase activity were measured in populations of cultured human aortic smooth muscle cells (ASMCs). Selective ligands of histamine and EP receptors were used to identify the receptors that mediate the responses. KEY RESULTS Histamine, via H1 receptors, stimulates an increase in [Ca(2+) ]i that is entirely mediated by activation of inositol 1,4,5-trisphosphate receptors. Selective stimulation of EP2 or EP4 receptors attenuates histamine-evoked Ca(2+) signals, but the effects of PGE2 on both Ca(2+) signals and AC activity are largely mediated by EP2 receptors. CONCLUSIONS AND IMPLICATIONS Two important inflammatory mediators, histamine via H1 receptors and PGE2 acting largely via EP2 receptors, exert opposing effects on [Ca(2+) ]i in human ASMCs.
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Säfholm J, Dahlén SE, Delin I, Maxey K, Stark K, Cardell LO, Adner M. PGE2 maintains the tone of the guinea pig trachea through a balance between activation of contractile EP1 receptors and relaxant EP2 receptors. Br J Pharmacol 2013; 168:794-806. [PMID: 22934927 DOI: 10.1111/j.1476-5381.2012.02189.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 07/23/2012] [Accepted: 08/20/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The guinea pig trachea (GPT) is commonly used in airway pharmacology. The aim of this study was to define the expression and function of EP receptors for PGE(2) in GPT as there has been ambiguity concerning their role. EXPERIMENTAL APPROACH Expression of mRNA for EP receptors and key enzymes in the PGE(2) pathway were assessed by real-time PCR using species-specific primers. Functional studies of GPT were performed in tissue organ baths. KEY RESULTS Expression of mRNA for the four EP receptors was found in airway smooth muscle. PGE(2) displayed a bell-shaped concentration-response curve, where the initial contraction was inhibited by the EP(1) receptor antagonist ONO-8130 and the subsequent relaxation by the EP(2) receptor antagonist PF-04418948. Neither EP(3) (ONO-AE5-599) nor EP(4) (ONO-AE3-208) selective receptor antagonists affected the response to PGE(2). Expression of COX-2 was greater than COX-1 in GPT, and the spontaneous tone was most effectively abolished by selective COX-2 inhibitors. Furthermore, ONO-8130 and a specific PGE(2) antibody eliminated the spontaneous tone, whereas the EP(2) antagonist PF-04418948 increased it. Antagonists of other prostanoid receptors had no effect on basal tension. The relaxant EP(2) response to PGE(2) was maintained after long-term culture, whereas the contractile EP(1) response showed homologous desensitization to PGE(2), which was prevented by COX-inhibitors. CONCLUSIONS AND IMPLICATIONS Endogenous PGE(2), synthesized predominantly by COX-2, maintains the spontaneous tone of GPT by a balance between contractile EP(1) receptors and relaxant EP(2) receptors. The model may be used to study interactions between EP receptors.
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Affiliation(s)
- J Säfholm
- Unit for Experimental Asthma and Allergy Research, Centre for Allergy Research, The Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Distinct roles of central and peripheral prostaglandin E2 and EP subtypes in blood pressure regulation. Am J Hypertens 2012; 25:1042-9. [PMID: 22695507 DOI: 10.1038/ajh.2012.67] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Prostaglandin E(2) (PGE(2)) is a major prostanoid with a wide variety of biological activities. PGE(2) can influence blood pressure (BP) both positively and negatively. In particular, centrally administered PGE(2) induces hypertension whereas systemic administration of PGE(2) produces a hypotensive effect. These physiologically opposing effects are generated by the existence of multiple EP receptors, namely EP(1-4), which are G protein-coupled receptors with distinct signaling properties. This review highlights the distinct roles of PGE(2) in BP regulation and the involvement of specific EP receptor subtypes.
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Philipose S, Konya V, Lazarevic M, Pasterk LM, Marsche G, Frank S, Peskar BA, Heinemann A, Schuligoi R. Laropiprant attenuates EP3 and TP prostanoid receptor-mediated thrombus formation. PLoS One 2012; 7:e40222. [PMID: 22870195 PMCID: PMC3411562 DOI: 10.1371/journal.pone.0040222] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 06/02/2012] [Indexed: 11/24/2022] Open
Abstract
The use of the lipid lowering agent niacin is hampered by a frequent flush response which is largely mediated by prostaglandin (PG) D2. Therefore, concomitant administration of the D-type prostanoid (DP) receptor antagonist laropiprant has been proposed to be a useful approach in preventing niacin-induced flush. However, antagonizing PGD2, which is a potent inhibitor of platelet aggregation, might pose the risk of atherothrombotic events in cardiovascular disease. In fact, we found that in vitro treatment of platelets with laropiprant prevented the inhibitory effects of PGD2 on platelet function, i.e. platelet aggregation, Ca2+ flux, P-selectin expression, activation of glycoprotein IIb/IIIa and thrombus formation. In contrast, laropiprant did not prevent the inhibitory effects of acetylsalicylic acid or niacin on thrombus formation. At higher concentrations, laropiprant by itself attenuated platelet activation induced by thromboxane (TP) and E-type prostanoid (EP)-3 receptor stimulation, as demonstrated in assays of platelet aggregation, Ca2+ flux, P-selectin expression, and activation of glycoprotein IIb/IIIa. Inhibition of platelet function exerted by EP4 or I-type prostanoid (IP) receptors was not affected by laropiprant. These in vitro data suggest that niacin/laropiprant for the treatment of dyslipidemias might have a beneficial profile with respect to platelet function and thrombotic events in vascular disease.
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Affiliation(s)
- Sonia Philipose
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Viktoria Konya
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Mirjana Lazarevic
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Lisa M. Pasterk
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Gunther Marsche
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Sasa Frank
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Bernhard A. Peskar
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Akos Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
- * E-mail:
| | - Rufina Schuligoi
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
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Ishida K, Matsumoto T, Taguchi K, Kamata K, Kobayashi T. Protein kinase C delta contributes to increase in EP3 agonist-induced contraction in mesenteric arteries from type 2 diabetic Goto-Kakizaki rats. Pflugers Arch 2012; 463:593-602. [PMID: 22371141 DOI: 10.1007/s00424-012-1088-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 02/02/2012] [Accepted: 02/16/2012] [Indexed: 01/26/2023]
Abstract
Prostaglandin E(2) (PGE(2)), an important and ubiquitously present vasoactive eicosanoid, may either constrict or dilate systemic vascular beds. However, little is known about the vascular contractile responsiveness to and signaling pathways for PGE(2) at the chronic stage of type 2 diabetes. We hypothesized that PGE(2)-induced arterial contraction is augmented in type 2 diabetic Goto-Kakizaki (GK) rats via the protein kinase Cδ (PKCδ) pathway. Here, we investigated the vasoconstrictor effects of PGE(2) and of sulprostone (EP1-/EP3-receptor agonist) in rings cut from superior mesenteric arteries isolated from GK rats (37-44 weeks old). In arteries from GK rats (vs. those from age-matched Wistar rats), examined in the presence of a nitric oxide synthase inhibitor: 1) the PGE(2)- and sulprostone-induced vasocontractions (which were not blocked by the selective EP1 receptor antagonist sc19220) were enhanced, and these enhancements were suppressed by rottlerin (selective PKCδ inhibitor) but not by Gö6976 (selective PKCα/β inhibitor); 2) the sulprostone-stimulated phosphorylation of PKCδ (at Thr(505)), which yields an active form, was increased and 3) sulprostone-stimulated caldesmon phosphorylations, which are related to isometric force generation in smooth muscle, were increased. The protein expression of EP3 receptor in superior mesenteric arteries was similar between the two groups of rats. Our data suggest that the diabetes-related enhancement of EP3 receptor-mediated vasocontraction results from activation of the PKCδ pathway. Alterations in EP3 receptor-mediated vasocontraction may be important factors in the pathophysiological influences over arterial tone that are present in diabetic states.
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Affiliation(s)
- Keiko Ishida
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
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Jones RL, Woodward DF, Wang JW, Clark RL. Roles of affinity and lipophilicity in the slow kinetics of prostanoid receptor antagonists on isolated smooth muscle preparations. Br J Pharmacol 2011; 162:863-79. [PMID: 20973775 PMCID: PMC3042197 DOI: 10.1111/j.1476-5381.2010.01087.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/24/2010] [Accepted: 10/04/2010] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE The highly lipophilic acyl-sulphonamides L-798106 and L-826266 showed surprisingly slow antagonism of the prostanoid EP₃ receptor system in guinea-pig aorta. Roles of affinity and lipophilicity in the onset kinetics of these and other prostanoid ligands were investigated. EXPERIMENTAL APPROACH Antagonist selectivity was assessed using a panel of human recombinant prostanoid receptor-fluorimetric imaging plate reader assays. Potencies/affinities and onset half-times of agonists and antagonists were obtained on guinea-pig-isolated aorta and vas deferens. n-Octanol-water partition coefficients were predicted. KEY RESULTS L-798106, L-826266 and the less lipophilic congener (DG)-3ap appear to behave as selective, competitive-reversible EP₃ antagonists. For ligands of low to moderate lipophilicity, potency increments for EP₃ and TP (thromboxane-like) agonism on guinea-pig aorta (above pEC₅₀ of 8.0) were associated with progressively longer onset half-times; similar trends were found for TP and histamine H₁ antagonism above a pA₂ limit of 8.0. In contrast, L-798106 (EP₃), L-826266 (EP₃, TP) and the lipophilic H₁ antagonists astemizole and terfenadine exhibited very slow onset rates despite their moderate affinities; (DG)-3ap (EP₃) had a faster onset. Agonism and antagonism on the vas deferens EP₃ system were overall much faster, although trends were similar. CONCLUSIONS AND IMPLICATIONS High affinity and high liphophilicity may contribute to the slow onsets of prostanoid ligands in some isolated smooth muscle preparations. Both relationships are explicable by tissue disposition under the limited diffusion model. EP₃ antagonists used as research tools should have moderate lipophilicity. The influence of lipophilicity on the potential clinical use of EP₃ antagonists is discussed.
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MESH Headings
- Acrylamides/chemistry
- Acrylamides/metabolism
- Acrylamides/pharmacology
- Animals
- Aorta, Thoracic/metabolism
- Guinea Pigs
- HEK293 Cells
- Humans
- Hydrophobic and Hydrophilic Interactions
- In Vitro Techniques
- Isoenzymes/antagonists & inhibitors
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Kinetics
- Ligands
- Male
- Models, Biological
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle, Smooth/drug effects
- Muscle, Smooth/metabolism
- Naphthalenes/chemistry
- Naphthalenes/metabolism
- Naphthalenes/pharmacology
- Neuromuscular Agents/chemistry
- Neuromuscular Agents/metabolism
- Neuromuscular Agents/pharmacology
- Receptors, Eicosanoid/agonists
- Receptors, Eicosanoid/antagonists & inhibitors
- Receptors, Eicosanoid/genetics
- Receptors, Eicosanoid/metabolism
- Receptors, Prostaglandin E, EP3 Subtype/agonists
- Receptors, Prostaglandin E, EP3 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP3 Subtype/genetics
- Receptors, Prostaglandin E, EP3 Subtype/metabolism
- Recombinant Proteins/agonists
- Recombinant Proteins/antagonists & inhibitors
- Recombinant Proteins/metabolism
- Sulfonamides/metabolism
- Sulfonamides/pharmacology
- Vas Deferens/metabolism
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Affiliation(s)
- R L Jones
- Cardiovascular Research Group, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
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