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In vitro and in silico studies of 8(17),12E,14-labdatrien-18-oic acid in airways smooth muscle relaxation: new molecular insights about its mechanism of action. Naunyn Schmiedebergs Arch Pharmacol 2020; 394:885-902. [PMID: 33205250 DOI: 10.1007/s00210-020-02010-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/26/2020] [Indexed: 10/23/2022]
Abstract
In the field of experimental pharmacology, researchers continuously investigate new relaxant agents of the airway smooth muscle cells (ASMCs), since the pathophysiology of respiratory illnesses, such as asthma, involves hyperresponsiveness and changes in ASMC homeostasis. In this scenario, labdane-type diterpenes, like forskolin (FSK), are a class of compounds known for their relaxing action on smooth muscle cells (SMCs), being this phenomenon related to the direct activation of AC-cAMP-PKA pathway. Considering the continuous effort of our group to study the mechanism of action and prospecting for compounds isolated from natural sources, in this paper, we presented how the diterpene 8(17),12E,14-labdatrien-18-oic acid (LBD) promotes relaxant effect on ASMC, performing in vitro experiments using isolated guinea pig trachea and in silico molecular docking/dynamics simulations. In vitro experiments showed that in the presence of aminophylline, FSK and LBD had their relaxant effect potentiated (EC50 from 1.4 ± 0.2 × 10-5 M to 1.5 ± 0.3 × 10-6 M for LBD and from 2.0 ± 0.2 × 10-7 M to 6.4 ± 0.4 × 10-8 M for FSK) while in the presence of Rp-cAMPS this effect was attenuated (EC50 from 1.4 ± 0.2 × 10-5 M to 3 × 10-4 M for LBD and from 2.0 ± 0.2 × 10-7 to 3.1 ± 1.0 × 10-6 M for FSK). Additionally, in silico simulations evidenced that the lipophilic character of LBD is probably responsible for its stability on AC binding site. LBD presented two preferential orientations, where the double bonds of the isoprene moiety as well as the unique polar group (carboxylic acid) in this compound form important anchoring points. In this sense, we consider that the LBD can interact stabilizing the catalytic dimmer of AC as the FSK, although less efficiently.
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Fodor GH, Bayat S, Babik B, Habre W, Peták F. Reversing Cholinergic Bronchoconstriction by Common Inotropic Agents: A Randomized Experimental Trial on Isolated Perfused Rat Lungs. Anesth Analg 2019; 129:745-752. [PMID: 31425216 DOI: 10.1213/ane.0000000000003502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The ability of inotropic agents to alter airway reactivity and lung tissue mechanics has not been compared in a well-controlled experimental model. Therefore, we compared the potential to alter lung tissue viscoelasticity and bronchodilator effects of commonly used inotropic agents in an isolated perfused rat lung model. METHODS After achieving steady state lung perfusion, sustained bronchoconstriction was induced by acetylcholine (ACh). Isolated rat lungs were then randomly allocated to 6 groups treated with either saline vehicle (n = 8) or incremental concentrations of inotropes (adrenaline, n = 8; dopamine, n = 7; dobutamine, n = 7; milrinone, n = 8; or levosimendan, n = 6) added to the whole-blood perfusate. Airway resistance (Raw), lung tissue damping (G), and elastance were measured under baseline conditions, during steady-state ACh-induced constriction and for each inotrope dose. RESULTS No change in Raw was observed after addition of the saline vehicle. Raw was significantly lower after addition of dopamine (maximum difference [95% CI] of 29 [12-46]% relative to the saline control, P = .004), levosimendan (58 [39-77]%, P < .001), and adrenaline (37 [21-53]%, P < .001), whereas no significant differences were observed at any dose of milrinone (5 [-12 to 22]%) and dobutamine (4 [-13 to 21]%). Lung tissue damping (G) was lower in animals receiving the highest doses of adrenaline (difference: 22 [7-37]%, P = .015), dobutamine (20 [5-35]%, P = .024), milrinone (20 [6-34]%, P = .026), and levosimendan (36 [19-53]%, P < .001) than in controls. CONCLUSIONS Although dobutamine and milrinone did not reduce cholinergic bronchoconstriction, they reversed the ACh-induced elevations in lung tissue resistance. In contrast, adrenaline, dopamine, and levosimendan exhibited both potent bronchodilatory action against ACh and diminished lung tissue damping. Further work is needed to determine whether these effects are clinically relevant in humans.
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Affiliation(s)
- Gergely H Fodor
- From the Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Sam Bayat
- From the Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Barna Babik
- Department of Anesthesiology and Intensive Care, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva and Pediatric Anesthesia Unit, Geneva Children's Hospital, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
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Menezes PMN, Brito MC, de Paiva GO, Dos Santos CO, de Oliveira LM, de Araújo Ribeiro LA, de Lima JT, Lucchese AM, Silva FS. Relaxant effect of Lippia origanoides essential oil in guinea-pig trachea smooth muscle involves potassium channels and soluble guanylyl cyclase. JOURNAL OF ETHNOPHARMACOLOGY 2018; 220:16-25. [PMID: 29609011 DOI: 10.1016/j.jep.2018.03.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 03/17/2018] [Accepted: 03/29/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Lippia origanoides H.B.K. is an aromatic species used in folk medicine to treat respiratory diseases, including asthma. AIM OF THE STUDY The aim of this work was to evaluate the relaxing potential and mechanism of action of the L. origanoides (LOO) essential oil in isolated guinea-pig trachea. MATERIALS AND METHODS Leaves from L. origanoides were collected at experimental fields under organic cultivation, at the Forest Garden of Universidade Estadual de Feira de Santana. Essential oil was extracted by hydrodistillation, analyzed by GC/FID and GC/MS and the volatile constituents were identified. Spasmolytic activity and relaxant mechanism of LOO were assayed in isolated guinea-pig trachea contracted with histamine, carbachol or hyperpolarizing KCl. RESULTS Chemical analysis revealed the presence of carvacrol (53.89%) as major constituent. LOO relaxed isolated guinea-pig trachea pre-contracted with KCl 60 mM [EC50 = 30.02 μg/mL], histamine 1 µM [EC50 = 9.28 μg/mL] or carbachol 1 µM [EC50 = 51.80 μg/mL]. The pre-incubation of glibenclamide, CsCl, propranolol, indomethacin, hexamethonium, aminophylline or L-NAME in histamine-induced contractions did not alter significantly the relaxant effect of LOO. However, the presence of 4-aminopyridine, tetraethylammonium or methylene blue reduced LOO effect, while the presence of dexamethasone or atropine potentialized the LOO relaxant effect. LOO pre-incubation inhibited carbachol-evoked contractions, with this effect potentialized in the presence of sodium nitroprusside and blocked in the presence of ODQ. CONCLUSIONS The relaxant mechanism of LOO on the tracheal smooth muscle possibly involves stimulating of soluble guanylyl cyclase with consequent activation of the voltage-gated and Ca2+-activated K+ channels.
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Affiliation(s)
| | - Mariana Coelho Brito
- Colegiado de Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil.
| | | | | | - Lenaldo Muniz de Oliveira
- Horto Florestal, Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana (UEFS), Brazil.
| | - Luciano Augusto de Araújo Ribeiro
- Pós-graduação em Recursos Naturais do Semiárido, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil; Colegiado de Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil.
| | - Julianeli Tolentino de Lima
- Pós-graduação em Recursos Naturais do Semiárido, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil; Colegiado de Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil.
| | - Angélica Maria Lucchese
- Laboratório de Química de Produtos Naturais e Bioativos, Departamento de Ciências Exatas, Universidade Estadual de Feira de Santana (UEFS), Brazil.
| | - Fabrício Souza Silva
- Pós-graduação em Recursos Naturais do Semiárido, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil; Colegiado de Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), Brazil.
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Wicher SA, Lawson KL, Jacoby DB, Fryer AD, Drake MG. Ozone-induced eosinophil recruitment to airways is altered by antigen sensitization and tumor necrosis factor- α blockade. Physiol Rep 2017; 5:e13538. [PMID: 29242307 PMCID: PMC5742702 DOI: 10.14814/phy2.13538] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/23/2017] [Accepted: 10/23/2017] [Indexed: 01/21/2023] Open
Abstract
Ozone is an atmospheric pollutant that causes lung inflammation and airway hyperresponsiveness. Ozone's effects occur in two distinct phases that are mediated by different populations of eosinophils. In the acute phase 1 day after exposure, mature airway-resident eosinophils alter parasympathetic nerve function that results in airway hyperresponsiveness. At this time point, the severity of hyperresponsiveness correlates with the number of eosinophils in close proximity to airway nerves, but not with eosinophils in bronchoalveolar lavage. Three days later, newly divided eosinophils are recruited to airways by a tumor necrosis factor-α-dependent mechanism. These new eosinophils paradoxically attenuate ozone-induced airway hyperresponsiveness. Ozone's effects on airway tissue eosinophils and nerve-associated eosinophils 3 days after exposure are unknown. Thus, we tested ozone's effects on eosinophils in airway subepithelium and around airway nerves 1 and 3 days after ozone in nonsensitized and ovalbumin-sensitized guinea pigs with or without the tumor necrosis factor-α antagonist, etanercept, and compared changes in eosinophils with ozone-induced airway hyperresponsiveness. More eosinophils were present in small, noncartilaginous airways and along small airway nerves compared to large cartilaginous airways in all treatment groups. The number of airway and nerve-associated eosinophils were unaffected 1 day after ozone exposure, whereas significantly fewer airway eosinophils were present 3 days later. Airway and nerve-associated eosinophils were also decreased in small airways 3 days after ozone in sensitized animals. These changes were blocked by etanercept. Airway eosinophils, but not nerve-associated or bronchoalveolar lavage eosinophils correlated with airway hyperresponsiveness 3 days after ozone. Our findings indicate ozone causes persistent alterations in airway eosinophils and reinforce the importance of characterizing eosinophils' effects within distinct airway compartments.
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Affiliation(s)
- Sarah A Wicher
- Department of Physiology and Pharmacology, Oregon Health & Sciences University, Portland, Oregon
| | - Katy L Lawson
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - David B Jacoby
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Allison D Fryer
- Department of Physiology and Pharmacology, Oregon Health & Sciences University, Portland, Oregon
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Matthew G Drake
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Oregon Health & Science University, Portland, Oregon
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Dealing with Ophthalmic Chemosurgery Complications. Anesthesiology 2017; 127:586-587. [PMID: 28816788 DOI: 10.1097/aln.0000000000001762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Segura-Cabrera A, García-Pérez C, Ciprés-Flores F, Cuevas-Hernández R, Trujillo-Ferrara J, Correa-Basurto J, Soriano-Ursúa M. Molecular dynamics simulations to explore the active/inactive conformers of guinea pig β2adrenoceptor for the selective design of agonists or antagonists. MOLECULAR SIMULATION 2014. [DOI: 10.1080/08927022.2013.857771] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Luo YL, Guo HM, Zhang YL, Chen PX, Zhu YX, Huang JH, Zhou WL. Cellular mechanism underlying formaldehyde-stimulated Cl- secretion in rat airway epithelium. PLoS One 2013; 8:e54494. [PMID: 23372735 PMCID: PMC3553115 DOI: 10.1371/journal.pone.0054494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 12/12/2012] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Recent studies suggest that formaldehyde (FA) could be synthesized endogeneously and transient receptor potential (TRP) channel might be the sensor of FA. However, the physiological significance is still unclear. METHODOLOGY/PRINCIPAL FINDINGS The present study investigated the FA induced epithelial Cl(-) secretion by activation of TRPV-1 channel located in the nerve ending fiber. Exogenously applied FA induced an increase of I(SC) in intact rat trachea tissue but not in the primary cultured epithelial cells. Western blot and immunofluorescence analysis identified TRPV-1 expression in rat tracheal nerve ending. Capsazepine (CAZ), a TRPV-1 specific antagonist significantly blocked the I(SC) induced by FA. The TRPV-1 agonist capsaicin (Cap) induced an increase of I(SC), which was similar to the I(SC) induced by FA. L-703606, an NK-1 specific inhibitor and propranolol, an adrenalin β receptor inhibitor significantly abolished the I(SC) induced by FA or Cap. In the ion substitute analysis, FA could not induce I(SC) in the absence of extracelluar Cl(-). The I(SC) induced by FA could be blocked by the non-specific Cl(-) channel inhibitor DPC and the CFTR specific inhibitor CFTR(i-172), but not by the Ca(2+)-activated Cl(-) channel inhibitor DIDS. Furthermore, both forskolin, an agonist of adenylate cyclase (AC) and MDL-12330A, an antagonist of AC could block FA-induced I(SC). CONCLUSION Our results suggest that FA-induced epithelial I(SC) response is mediated by nerve, involving the activation of TRPV-1 and release of adrenalin as well as substance P.
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Affiliation(s)
- Yu-Li Luo
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Hong-Mei Guo
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yi-Lin Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Peng-Xiao Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yun-Xin Zhu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jie-Hong Huang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen-Liang Zhou
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Arai M, Sato T, Takeuchi S, Goto S, Togari A. Dose effects of butoxamine, a selective β2-adrenoceptor antagonist, on bone metabolism in spontaneously hypertensive rat. Eur J Pharmacol 2013; 701:7-13. [PMID: 23321373 DOI: 10.1016/j.ejphar.2012.12.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 12/18/2012] [Accepted: 12/19/2012] [Indexed: 12/17/2022]
Abstract
Recent studies have shown that osteoblasts and osteoclasts express β2-adrenoceptor, and increased sympathetic nervous activity causes bone loss via an increase in osteoclastic bone resorption and a decrease in osteoblastic bone formation. We previously demonstrated that non-selective β-adrenoceptor antagonist propranolol at low doses (0.1 and 1mg/kg), but not at a higher dose (10mg/kg), prevented a decrease in bone mass and an increase in bone fragility in spontaneously hypertensive rat (SHR), an animal model of osteoporosis with hyperactivity of the sympathetic nervous system, without affecting blood pressure. In the present study, the dose effects of butoxamine, a selective β2-adrenoceptor antagonist, on bone metabolism were examined in SHR by analysis of microcomputed tomography, bone histomorphometry, biomechanical testing and plasma biochemistry. Treatment of SHR with butoxamine at 0.1, 1 and 10mg/kg (per os) for 12 weeks increased bone mass indices and biomechanical parameters of strength and toughness of the lumbar vertebrae, suggesting antiosteoporotic activity. Butoxamine dose-dependently decreased osteoclast number and surface per bone surface with decreases in plasma tartrate-resistant acid phosphatase-5b level, a biochemical index of osteoclastic activity. On the other hand, histomorphometry indices of bone formation and plasma osteocalcin concentration reflecting osteoblastic activity were increased in SHR treated with butoxamine at 0.1 and 1mg/kg, but not at 10mg/kg. These results suggest that β-adrenoceptor antagonists at a low dose may improve osteoporosis with hyperactivity of the sympathetic nervous system via β2-adrenoceptor blocking action, while they may have a somewhat inhibitory effect on osteoblastic activity at a high dose.
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Affiliation(s)
- Michitsugu Arai
- Department of Pharmacology, Aichi-Gakuin University, Nagoya, Japan
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Seidel P, Alkhouri H, Lalor DJ, Burgess JK, Armour CL, Hughes JM. Thiazolidinediones inhibit airway smooth muscle release of the chemokine CXCL10: in vitro comparison with current asthma therapies. Respir Res 2012; 13:90. [PMID: 23034049 PMCID: PMC3503570 DOI: 10.1186/1465-9921-13-90] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 09/27/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Activated mast cells are present within airway smooth muscle (ASM) bundles in eosinophilic asthma. ASM production of the chemokine CXCL10 plays a role in their recruitment. Thus the effects of glucocorticoids (fluticasone, budesonide), long-acting β2-agonists (salmeterol, formoterol) and thiazolidinediones (ciglitazone, rosiglitazone) on CXCL10 production by ASM cells (ASMC) from people with and without asthma were investigated in vitro. METHODS Confluent serum-deprived cells were treated with the agents before and during cytokine stimulation for 0-24 h. CXCL10 protein/mRNA, IκB-α levels and p65 activity were measured using ELISA, RT PCR, immunoblotting and p65 activity assays respectively. Data were analysed using ANOVA followed by Fisher's post-hoc test. RESULTS Fluticasone and/or salmeterol at 1 and 100 nM inhibited CXCL10 release induced by IL-1β and TNF-α, but not IFNγ or all three cytokines (cytomix). The latter was also not affected by budesonide and formoterol. In asthmatic ASMC low salmeterol, but not formoterol, concentrations increased cytomix-induced CXCL10 release and at 0.01 nM enhanced NF-κB activity. Salmeterol 0.1 nM together with fluticasone 0.1 and 10 nM still increased CXCL10 release. The thiazolidinediones ciglitazone and rosiglitazone (at 25 and 100 μM) inhibited cytomix-induced CXCL10 release but these inhibitory effects were not prevented by the PPAR-g antagonist GW9662. Ciglitazone did not affect early NF-κB activity and CXCL10 mRNA production. CONCLUSIONS Thus the thiazolidinediones inhibited asthmatic ASMC CXCL10 release under conditions when common asthma therapies were ineffective or enhanced it. They may provide an alternative strategy to reduce mast cell-ASM interactions and restore normal airway physiology in asthma.
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Affiliation(s)
- Petra Seidel
- Respiratory Research Group, Faculty of Pharmacy, The University of Sydney, A15, Science Rd, Sydney, NSW 2006, Australia
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Hothersall JD, Black J, Caddick S, Vinter JG, Tinker A, Baker JR. The design, synthesis and pharmacological characterization of novel β₂-adrenoceptor antagonists. Br J Pharmacol 2012; 164:317-31. [PMID: 21323900 DOI: 10.1111/j.1476-5381.2011.01269.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Selective and potent antagonists for the β(2) -adrenoceptor are potentially interesting as experimental and clinical tools, and we sought to identify novel ligands with this pharmacology. EXPERIMENTAL APPROACH A range of pharmacological assays was used to assess potency, affinity, selectivity (β(2) -adrenoceptor vs. β(1) -adrenoceptor) and efficacy. KEY RESULTS Ten novel compounds were identified but none had as high affinity as the prototypical β(2) -adrenoceptor blocker ICI-118,551, although one of the novel compounds was more selective for β(2) -adrenoceptors. Most of the ligands were inverse agonists for β(2) -adrenoceptor-cAMP signalling, although one (5217377) was a partial agonist and another a neutral antagonist (7929193). None of the ligands were efficacious with regard to β(2) -adrenoceptor-β-arrestin signalling. The (2S,3S) enantiomers were identified as the most active, although unusually the racemates were the most selective for the β(2) -adrenoceptors. This was taken as evidence for some unusual enantiospecific behaviour. CONCLUSIONS AND IMPLICATIONS In terms of improving on the pharmacology of the ligand ICI-118,551, one of the compounds was more selective (racemic JB-175), while one was a neutral antagonist (7929193), although none had as high an affinity. The results substantiate the notion that β-blockers do more than simply inhibit receptor activation, and differences between the ligands could provide useful tools to investigate receptor biology.
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Aworet-Samseny RRR, Souza A, Kpahé F, Konaté K, Datté JY. Dichrostachys cinerea (L.) Wight et Arn (Mimosaceae) hydro-alcoholic extract action on the contractility of tracheal smooth muscle isolated from guinea-pig. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 11:23. [PMID: 21414220 PMCID: PMC3068131 DOI: 10.1186/1472-6882-11-23] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 03/17/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Dichrostachys cinerea (L.) Wight et Arn. (Mimosaceae) is largely used in ethno-medically across Africa, and mainly employed for the treatment of asthma in Ivory Coast and Gabon. The paper analyses the relaxation induced by the methanolic extract of D. cinerea (Edici) in the guinea-pig trachea preparations (GPTPs). PURPOSE This study aimed to bring out the scientific basis to the use of this plant leading to the validation of this phytomedicine. METHOD The aorta obtained from guinea-pigs was immediately placed in a Mac Ewen solution. Experiments were performed in preparations suspended between two L-shaped stainless steel hooks in a 10 ml organ bath containing Mac Ewen solution. The isometric contractile force of the aorta strips of guinea-pig were recorded by using a strain gauge. The different drugs were directly administered into the organ bath and the magnitude of GPTPs was evaluated. RESULTS Phytochemical analysis of the methanolic extract of Dichrostachys cinerea (Edici) using chemical methods revealed the presence of flavenoids, tannins, sterols, triterpenes and polyphenols. Pharmacological studies performed in GPTPs show that of Dichrostachys cinerea (0.1 mg/ml - 2 mg/ml) evoked a broncho-constriction in GPTPs. Whereas, at concentration up to 2 mg/ml, Edici induced a significant dose-dependent relaxation in the GPTPs. KCl-, ACh- or histamine-evoked contractions of isolated trachea was significantly inhibited by increasing concentrations of Edici (3.5-10 mg/ml). Edici (10 mg/ml) as well as promethazine (0.25 mg/ml) significantly inhibited contractions induced by increasing concentrations of histamine (1×10-7-1×10-4mg/ml). In the presence of atropine at a concentration of 10-6mg/ml, contractile response curve (CRC) evoked by ACh (1×10-5-1×10-2 mg/ml) was significantly abolished in concentration-dependent manner. Edici did not significantly reduced ACh evoked contraction (10-5-10-2mg/ml). CONCLUSION These observations suggest that Edici could act through two mechanisms: firstly by activation of β-adrenergic or histaminergic receptors; and secondly muscarinic receptors may not be greatly involved, that justifying the use of the extract in traditional Medicine in Africa.
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Affiliation(s)
- Raissa RR Aworet-Samseny
- Institut de Pharmacopée et de Médecine Traditionnelle, Centre National de la Recherche Scientifique et Technologique (Cenarest) BP: 1156 Route de Sibang 3 Libreville Gabon
| | - Alain Souza
- Institut de Pharmacopée et de Médecine Traditionnelle, Centre National de la Recherche Scientifique et Technologique (Cenarest) BP: 1156 Route de Sibang 3 Libreville Gabon
| | - Fidele Kpahé
- Laboratoire de Nutrition et de Pharmacologie, UFR BioSciences, Université de Cocody, Abidjan 22 BP: 582 Abidjan -Côte d'Ivoire
| | - Kiessoun Konaté
- Laboratoire de Biochimie et de chimie Appliquées, UFR Science de la Vie et de la Terre, Université de Ouagadougou, 09 BP 848 Ouagadougou 09 Burkina Faso
| | - Jacques Y Datté
- Laboratoire de Nutrition et de Pharmacologie, UFR BioSciences, Université de Cocody, Abidjan 22 BP: 582 Abidjan -Côte d'Ivoire
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Soriano-Ursúa MA, Trujillo-Ferrara JG, Correa-Basurto J. Homology modeling and flex-ligand docking studies on the guinea pig beta(2) adrenoceptor: structural and experimental similarities/ differences with the human beta(2). J Mol Model 2009; 15:1203-11. [PMID: 19263094 DOI: 10.1007/s00894-009-0480-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 01/24/2009] [Indexed: 02/07/2023]
Abstract
The trachea of a guinea pig is widely used in drug development assays focused on the treatment of pulmonary diseases. Some of these drugs relax the airways by binding to the guinea pig beta(2)-adrenoceptor (Gbeta(2)AR). In this work, the amino acid sequence of the Gbeta(2)AR was searched to carry out homology modeling, using the Swiss-Model server, with the human beta(2)AR as the parent template. The Gbeta(2)AR 3-D structure was structurally and energetically optimized in vacuo using NAMD 2.6 program. The refined 3-D model obtained was used for further study. Molecular docking simulations were performed by testing a set of well-known beta(2)AR ligands using the AutoDock 3.0.5 program. The results show that the homology model of Gbeta(2)AR has a 3-D structure very similar to the crystal structure of recently studied human beta(2)AR. This was also corroborated by identity (94.23%), Ramachandran map, and docking results. The theoretical simulation showed that the ligands bind at sites that are similar to those reported for the human beta(2)AR. The R-enantiomer ligands showed correlation with in vitro data. We have obtained a Gbeta(2)AR 3-D model which can be used to carry out computational screening as a complementary tool during the drug design and experimental tests under guinea pig models.
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Abstract
The guinea pig has been the most commonly used small animal species in preclinical studies related to asthma and COPD. The primary advantages of the guinea pig are the similar potencies and efficacies of agonists and antagonists in human and guinea pig airways and the many similarities in physiological processes, especially airway autonomic control and the response to allergen. The primary disadvantages to using guinea pigs are the lack of transgenic methods, limited numbers of guinea pig strains for comparative studies and a prominent axon reflex that is unlikely to be present in human airways. These attributes and various models developed in guinea pigs are discussed.
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Affiliation(s)
- Brendan J Canning
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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Mazzanti G, Di Sotto A, Daniele C, Battinelli L, Brambilla G, Fiori M, Loizzo S, Loizzo A. A pharmacodynamic study on clenbuterol-induced toxicity: beta1- and beta2-adrenoceptors involvement in guinea-pig tachycardia in an in vitro model. Food Chem Toxicol 2007; 45:1694-9. [PMID: 17449161 DOI: 10.1016/j.fct.2007.03.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 02/21/2007] [Accepted: 03/05/2007] [Indexed: 11/27/2022]
Abstract
Beta(2)-receptor adrenergic agonists as clenbuterol and analogues are illegally used as growth promoters in cattle, in Europe, as well as in other countries. Following consumption of meat or liver, intoxication cases were described, and cardiovascular toxic effects (tachycardia, hypertension) were of clinical relevance. Therefore, we investigated whether heart rate increase induced by clenbuterol could depend upon stimulation of beta(1)- and/or beta(2)-adrenergic receptors, and in which ratio. We used in vitro guinea-pig atria, a model in which beta(1)-/beta(2)-receptors ratio is similar to that found in men. In our experiments both beta(1)- and beta(2)-receptors contributed to clenbuterol-induced heart rate increase, but with a different potency. The selective beta(2)-antagonist ICI-118,551 competitively antagonized responses to clenbuterol with high affinity (pA(2) 9.47+/-0.28, SchildSlope 0.98+/-0.20 not significantly different from unity, K(B) 0.34 nM). The selective beta(1)-antagonist atenolol antagonized clenbuterol with a relatively lower affinity (pA(2)=7.59+/-0.14), the SchildSlope=1.97+/-0.33 was significantly different from unity (P<0.05). Results show that clenbuterol stimulates guinea-pig heart rate by acting chiefly on beta(2)-adrenoceptor, although responses to clenbuterol apparently are mediated by an inter-play between both beta-adrenoceptors. Further experiments are necessary to understand which beta-adrenergic antagonists are of effectiveness to counteract cardiovascular effects in case of intoxication following clenbuterol, or other beta-adrenergic stimulants.
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Affiliation(s)
- Gabriela Mazzanti
- Department of Human Physiology and Pharmacology, University La Sapienza, P.le Aldo Moro, 5-00185 Rome, Italy
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Tanaka Y, Yamashita Y, Michikawa H, Horinouchi T, Koike K. Pharmacological characterization of the β-adrenoceptor that mediates the relaxant response to noradrenaline in guinea-pig tracheal smooth muscle. Naunyn Schmiedebergs Arch Pharmacol 2007; 375:51-64. [PMID: 17237919 DOI: 10.1007/s00210-006-0130-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 12/18/2006] [Indexed: 11/25/2022]
Abstract
Pharmacological characteristics of beta-adrenoceptors (beta-ARs) mediating noradrenaline-induced relaxation were investigated in guinea-pig tracheal smooth muscle. The inhibitory effects of several types of beta-AR antagonists on noradrenaline-induced relaxation against histamine contraction were scrutinized with Schild plot analysis. The concentration-response curve for noradrenaline obtained in the absence of phentolamine and uptake inhibitors was competitively antagonized by all of the beta-AR antagonists used in this study (propranolol, bupranolol, atenolol, butoxamine and ICI-118,551). However, their pA2 values were markedly less than the expected values for beta1-AR and beta2-AR. On the other hand, pA2 values of ICI-118,551 (6.85) determined in the presence of phentolamine suggested a contribution of a beta1 -AR rather than beta2 -AR. In the presence of phentolamine and uptake inhibitors (desipramine and deoxycorticosterone), the Schild plot for atenolol was a better fit, with two distinct straight lines. The pA2 values of atenolol provided by the regression were: approximately 7.0, which corresponds to the expected beta1-AR value, and approximately 6.5, which was 3 times less than the expected value for beta1 -AR, and thus the possible presence of two classes of beta1 -AR (beta1(Low) and beta1(High)) was suggested. This view was also supported by Schild plot analysis for propranolol, which fit two straight lines each with a slope of 1.0. The present findings indicate that beta1 -ARs contributing to noradrenaline-elicited relaxation in guinea-pig tracheal smooth muscle exhibit diverse pharmacological characteristics and may be subdivided into at least two classes with distinct affinities for atenolol. Under physiological conditions, beta1(Low) rather than beta1(High) seems to play a more significant role in noradrenaline-regulated airway smooth muscle tone.
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Affiliation(s)
- Yoshio Tanaka
- Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, 2-2-1 Miyama, Funabashi-City, Chiba, 274-8510, Japan.
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