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Fatoki T, Awofisayo O, Faleye B. Cipargamin could inhibit human adenosine receptor A3 with higher binding affinity than Plasmodium falciparum P-type ATPase 4: An In silico study. ACTA FACULTATIS MEDICAE NAISSENSIS 2022. [DOI: 10.5937/afmnai39-31499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Aim: This study aimed to predict the molecular targets of cipargamin in humans and estimate the structural dynamics and binding affinity of their interactions compared to that of Plasmodium falciparum P-type ATPase 4 (PfATP4). Methods: In silico methods were used in this study which include target prediction, structure modeling and dynamics, and molecular docking. Results: The results showed that cipargamin had 100% probability of binding to the human adenosine A3 receptor (ADORA3) and about 15% for other human targets which include tyrosine-protein kinase JAK2, adenosine A2a receptor, phosphodiesterase 5A and cathepsin K. The results of molecular docking showed that binding energy of cipargamin to PfATP4 and hADORA3 were-12.40 kcal/mol-1 and-13.40 kcal/mol-1 respectively. The docking was validated by the binding of enprofylline and fostamatinib to PfATP4 and hADORA3. Overall, the binding of cipargamin was closely similar to that of fostamatinib. This study shows the potential of cipargamin to modulate the activities of PfATP4 of the parasite (P. falciparum) as well as ADORA3 of the host (Homo sapiens). Conclusion: All the previous studies of cirpagamin have not implicated its action on hADORA3, thus this study provides an insight into a possible role of hADORA3 in the mechanism of malarial infection.
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Mangoni AA, Tommasi S, Zinellu A, Sotgia S, Bassu S, Piga M, Erre GL, Carru C. Methotrexate and Vasculoprotection: Mechanistic Insights and Potential Therapeutic Applications in Old Age. Curr Pharm Des 2019; 25:4175-4184. [DOI: 10.2174/1381612825666191112091700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 11/07/2019] [Indexed: 02/06/2023]
Abstract
Increasing age is a strong, independent risk factor for atherosclerosis and cardiovascular disease. Key
abnormalities driving cardiovascular risk in old age include endothelial dysfunction, increased arterial stiffness,
blood pressure, and the pro-atherosclerotic effects of chronic, low-grade, inflammation. The identification of
novel therapies that comprehensively target these alterations might lead to a major breakthrough in cardiovascular
risk management in the older population. Systematic reviews and meta-analyses of observational studies have
shown that methotrexate, a first-line synthetic disease-modifying anti-rheumatic drug, significantly reduces
cardiovascular morbidity and mortality in patients with rheumatoid arthritis, a human model of systemic
inflammation, premature atherosclerosis, and vascular aging. We reviewed in vitro and in vivo studies
investigating the effects of methotrexate on endothelial function, arterial stiffness, and blood pressure, and the
potential mechanisms of action involved. The available evidence suggests that methotrexate might have beneficial
effects on vascular homeostasis and blood pressure control by targeting specific inflammatory pathways,
adenosine metabolism, and 5' adenosine monophosphate-activated protein kinase. Such effects might be
biologically and clinically relevant not only in patients with rheumatoid arthritis but also in older adults with high
cardiovascular risk. Therefore, methotrexate has the potential to be repurposed for cardiovascular risk
management in old age because of its putative pharmacological effects on inflammation, vascular homeostasis,
and blood pressure. However, further study and confirmation of these effects are essential in order to adequately
design intervention studies of methotrexate in the older population.
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Affiliation(s)
- Arduino A. Mangoni
- Discipline of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, Australia
| | - Sara Tommasi
- Discipline of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, Australia
| | - Angelo Zinellu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Salvatore Sotgia
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Stefania Bassu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Matteo Piga
- Rheumatology Unit, University Clinic and AOU of Cagliari, Cagliari, Italy
| | - Gian L. Erre
- Rheumatology Unit, Department of Clinical and Experimental Medicine, University Hospital (AOUSS) and University of Sassari, Sassari, Italy
| | - Ciriaco Carru
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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Mangoni AA, Tommasi S, Zinellu A, Sotgia S, Carru C, Piga M, Erre GL. Repurposing existing drugs for cardiovascular risk management: a focus on methotrexate. Drugs Context 2018; 7:212557. [PMID: 30459819 PMCID: PMC6239018 DOI: 10.7573/dic.212557] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 12/12/2022] Open
Abstract
About 20% of patients with a history of atherosclerotic cardiovascular disease will experience further cardiovascular events despite maximal pharmacological treatment with cardioprotective drugs. This highlights the presence of residual cardiovascular risk in a significant proportion of patients and the need for novel, more effective therapies. These therapies should ideally target different pathophysiological pathways involved in the onset and the progression of atherosclerosis, particularly the inflammatory and immune pathways. Methotrexate is a first-line disease-modifying antirheumatic drug that is widely used for the management of autoimmune and chronic inflammatory disorders. There is some in vitro and in vivo evidence that methotrexate might exert a unique combination of anti-inflammatory, blood pressure lowering, and vasculoprotective effects. Pending the results of large prospective studies investigating surrogate end-points as well as morbidity and mortality, repurposing methotrexate for cardiovascular risk management might represent a cost-effective strategy with immediate public health benefits. This review discusses the current challenges in the management of cardiovascular disease; the available evidence on the effects of methotrexate on inflammation, blood pressure, and surrogate markers of arterial function; suggestions for future research directions; and practical considerations with the use of methotrexate in this context.
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Affiliation(s)
- Arduino A Mangoni
- Discipline of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, Australia
| | - Sara Tommasi
- Discipline of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, Australia
| | - Angelo Zinellu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Salvatore Sotgia
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Ciriaco Carru
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Quality Control Unit, University Hospital (AOUSS), Sassari, Italy
| | - Matteo Piga
- Rheumatology Unit, University Clinic and AOU of Cagliari, Italy
| | - Gian Luca Erre
- Rheumatology Unit, Department of Clinical and Experimental Medicine, University Hospital (AOUSS) and University of Sassari, Sassari, Italy
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Protective Effects of Methotrexate against Proatherosclerotic Cytokines: A Review of the Evidence. Mediators Inflamm 2017; 2017:9632846. [PMID: 29430085 PMCID: PMC5753000 DOI: 10.1155/2017/9632846] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/02/2017] [Accepted: 11/26/2017] [Indexed: 12/16/2022] Open
Abstract
There is good epidemiological evidence that patients with autoimmune rheumatic disease states, particularly rheumatoid arthritis, have an increased risk of cardiovascular morbidity and mortality when compared to the general population. The presence of a chronic systemic proinflammatory state in this patient group disrupts the structural and functional integrity of the endothelium and the arterial wall, favouring the onset and progression of atherosclerosis. A significant role in the detrimental effects of inflammation on endothelial function and vascular homeostasis is played by specific proatherosclerotic cytokines such as tumour necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6). Recent systematic reviews and meta-analyses have shown that treatment with methotrexate, a first-line disease-modifying antirheumatic drug (DMARD), is associated with a significant reduction in atherosclerosis-mediated cardiovascular events, such as myocardial infarction and stroke, and mortality, when compared to other DMARDs. This suggests that methotrexate might exert specific protective effects against vascular inflammation and atherosclerosis in the context of autoimmune rheumatic disease. This review discusses the available evidence regarding the potential antiatherosclerotic effects of methotrexate through the inhibition of TNF-α, IL-1, and IL-6 and provides suggestions for future experimental and human studies addressing this issue.
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Teng B, Tilley SL, Ledent C, Mustafa SJ. In vivo assessment of coronary flow and cardiac function after bolus adenosine injection in adenosine receptor knockout mice. Physiol Rep 2016; 4:4/11/e12818. [PMID: 27302991 PMCID: PMC4908494 DOI: 10.14814/phy2.12818] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/30/2016] [Indexed: 12/20/2022] Open
Abstract
Bolus injections of adenosine and the A2A adenosine receptor (AR) selective agonist (regadenoson) are used clinically as a substitute for a stress test in people who cannot exercise. Using isolated tissue preparations, our lab has shown that coronary flow and cardiac effects of adenosine are mostly regulated by the AR subtypes A1, A2A, and A2B In this study, we used ultrasound imaging to measure the in vivo effects of adenosine on coronary blood flow (left coronary artery) and cardiac function in anesthetized wild-type, A1 knockout (KO), A2AKO, A2BKO, A3KO, A1, and A3 double KO (A1/3 DKO) and A2A and A2B double KO (A2A/2B DKO) mice in real time. Echocardiographic and Doppler studies were performed using a Visualsonic Vevo 2100 ultrasound system. Coronary blood flow (CBF) baseline data were obtained when animals were anesthetized with 1% isoflourane. Diameter (D) and velocity time integral (VTI) were measured on the left coronary arteries (CBF = ((π/4) × D(2) × VTI × HR)/1000). CBF changes were the highest within 2 min of injection (about 10 mg/kg). Heart rate, cardiac output, and stroke volume were measured by tracing the left ventricle long axis. Our data support a role for the A2 AR in CBF and further support our conclusions of previous studies from isolated tissues. Adenosine-mediated decreases in cardiac output and stroke volume may be A2B and/or A3 AR-mediated; however, the A1 and A2 ARs also play roles in overall cardiac function. These data further provide a powerful translational tool in studying the cardiovascular effects of adenosine in disease states.
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Affiliation(s)
- Bunyen Teng
- Department of Physiology & Pharmacology, West Virginia University, Morgantown, West Virginia
| | - Stephen L Tilley
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | | | - S Jamal Mustafa
- Department of Physiology & Pharmacology, West Virginia University, Morgantown, West Virginia
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Ciruela F, Fernández-Dueñas V, Jacobson KA. Lighting up G protein-coupled purinergic receptors with engineered fluorescent ligands. Neuropharmacology 2015; 98:58-67. [PMID: 25890205 DOI: 10.1016/j.neuropharm.2015.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 03/23/2015] [Accepted: 04/01/2015] [Indexed: 12/31/2022]
Abstract
The use of G protein-coupled receptors fluorescent ligands is undergoing continuous expansion. In line with this, fluorescent agonists and antagonists of high affinity for G protein-coupled adenosine and P2Y receptors have been shown to be useful pharmacological probe compounds. Fluorescent ligands for A1R, A2AR, and A3R (adenosine receptors) and P2Y2R, P2Y4R, P2Y6R, and P2Y14R (nucleotide receptors) have been reported. Such ligands have been successfully applied to drug discovery and to GPCR characterization by flow cytometry, fluorescence correlation spectroscopy, fluorescence microscopy, fluorescence polarization, fluorescence resonance energy transfer and scanning confocal microscopy. Here we summarize recently reported and readily available representative fluorescent ligands of purinergic receptors. In addition, we pay special attention on the use of this family of fluorescent ligands revealing two main aspects of purinergic receptor biology, namely ligand binding and receptor oligomerization. This article is part of the Special Issue entitled 'Fluorescent Tools in Neuropharmacology'.
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Affiliation(s)
- Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Department of Physiology, Faculty of Sciences, University of Ghent, 9000 Gent, Belgium.
| | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Spain
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 20892 Bethesda, USA.
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Hide and seek: a comparative autoradiographic in vitro investigation of the adenosine A3 receptor. Eur J Nucl Med Mol Imaging 2015; 42:928-39. [PMID: 25739834 PMCID: PMC4382535 DOI: 10.1007/s00259-014-2985-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/29/2014] [Indexed: 11/15/2022]
Abstract
Purpose Since the adenosine A3 receptor (A3R) is considered to be of high clinical importance in the diagnosis and treatment of ischaemic conditions (heart and brain), glaucoma, asthma, arthritis, cancer and inflammation, a suitable and selective A3R PET tracer such as [18F]FE@SUPPY would be of high clinical value for clinicians as well as patients. A3R was discovered in the late 1990s, but there is still little known regarding its distribution in the CNS and periphery. Hence, in autoradiographic experiments the distribution of A3R in human brain and rat tissues was investigated and the specific binding of the A3R antagonist FE@SUPPY and MRS1523 compared. Immunohistochemical staining (IHC) experiments were also performed to validate the autoradiographic findings. Methods For autoradiographic competition experiments human post-mortem brain and rat tissues were incubated with [125I]AB-MECA and highly selective compounds to block the other adenosine receptor subtypes. Additionally, IHC was performed with an A3 antibody. Results Specific A3R binding of MRS1523 and FE@SUPPY was found in all rat peripheral tissues examined with the highest amounts in the spleen (44.0 % and 46.4 %), lung (44.5 % and 45.0 %), heart (39.9 % and 42.9 %) and testes (27.4 % and 29.5 %, respectively). Low amounts of A3R were found in rat brain tissues (5.9 % and 5.6 %, respectively) and human brain tissues (thalamus 8.0 % and 9.1 %, putamen 7.8 % and 8.2 %, cerebellum 6.0 % and 7.8 %, hippocampus 5.7 % and 5.6 %, caudate nucleus 4.9 % and 6.4 %, cortex 4.9 % and 6.3 %, respectively). The outcome of the A3 antibody staining experiments complemented the results of the autoradiographic experiments. Conclusion The presence of A3R protein was verified in central and peripheral tissues by autoradiography and IHC. The specificity and selectivity of FE@SUPPY was confirmed by direct comparison with MRS1523, providing further evidence that [18F]FE@SUPPY may be a suitable A3 PET tracer for use in humans.
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Ciruela F, Jacobson KA, Fernández-Dueñas V. Portraying G protein-coupled receptors with fluorescent ligands. ACS Chem Biol 2014; 9:1918-28. [PMID: 25010291 PMCID: PMC4168789 DOI: 10.1021/cb5004042] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
![]()
The
thermodynamics of ligand–receptor interactions at the
surface of living cells represents a fundamental aspect of G protein-coupled
receptor (GPCR) biology; thus, its detailed elucidation constitutes
a challenge for modern pharmacology. Interestingly, fluorescent ligands
have been developed for a variety of GPCRs in order to monitor ligand–receptor
binding in living cells. Accordingly, new methodological strategies
derived from noninvasive fluorescence-based approaches, especially
fluorescence resonance energy transfer (FRET), have been successfully
developed to characterize ligand–receptor interactions. Importantly,
these technologies are supplanting more hazardous and expensive radioactive
binding assays. In addition, FRET-based tools have also become extremely
powerful approaches for visualizing receptor–receptor interactions
(i.e., GPCR oligomerization) in living cells. Thus, by means of the
synthesis of compatible fluorescent ligands these novel techniques
can be implemented to demonstrate the existence of GPCR oligomerization
not only in heterologous systems but also in native tissues. Finally,
there is no doubt that these methodologies would also be relevant
in drug discovery in order to develop new high-throughput screening
approaches or to identify new therapeutic targets. Overall, herein,
we provide a thorough assessment of all technical and biological aspects,
including strengths and weaknesses, of these fluorescence-based methodologies
when applied to the study of GPCR biology at the plasma membrane of
living cells.
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Affiliation(s)
- Francisco Ciruela
- Unitat
de Farmacologia, Departament Patologia i Terapèutica Experimental,
Facultat de Medicina, IDIBELL, Universitat de Barcelona, L’Hospitalet
de Llobregat, 08907 Barcelona, Spain
| | - Kenneth A. Jacobson
- Molecular
Recognition Section, Laboratory of Bioorganic Chemistry, National
Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Víctor Fernández-Dueñas
- Unitat
de Farmacologia, Departament Patologia i Terapèutica Experimental,
Facultat de Medicina, IDIBELL, Universitat de Barcelona, L’Hospitalet
de Llobregat, 08907 Barcelona, Spain
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El-Mas MM, El-Gowilly SM, Fouda MA, Saad EI. Role of adenosine A2A receptor signaling in the nicotine-evoked attenuation of reflex cardiac sympathetic control. Toxicol Appl Pharmacol 2011; 254:229-37. [PMID: 21550361 DOI: 10.1016/j.taap.2011.04.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 04/18/2011] [Accepted: 04/21/2011] [Indexed: 12/27/2022]
Abstract
Baroreflex dysfunction contributes to increased cardiovascular risk in cigarette smokers. Given the importance of adenosinergic pathways in baroreflex control, the hypothesis was tested that defective central adenosinergic modulation of cardiac autonomic activity mediates the nicotine-baroreflex interaction. Baroreflex curves relating changes in heart rate (HR) to increases or decreases in blood pressure (BP) evoked by i.v. doses (1-16μg/kg) of phenylephrine (PE) and sodium nitroprusside (SNP), respectively, were constructed in conscious rats; slopes of the curves were taken as measures of baroreflex sensitivity (BRS). Nicotine (25 and 100μg/kg i.v.) dose-dependently reduced BRS(SNP) in contrast to no effect on BRS(PE). BRS(SNP) was also attenuated after intracisternal (i.c.) administration of nicotine. Similar reductions in BRS(SNP) were observed in rats pretreated with atropine or propranolol. The combined treatment with nicotine and atropine produced additive inhibitory effects on BRS, an effect that was not demonstrated upon concurrent exposure to nicotine and propranolol. BRS(SNP) was reduced in preparations treated with i.c. 8-phenyltheophylline (8-PT, nonselective adenosine receptor antagonist), 8-(3-Chlorostyryl) caffeine (CSC, A(2A) antagonist), or VUF5574 (A(3) antagonist). In contrast, BRS(SNP) was preserved after blockade of A(1) (DPCPX) or A(2B) (alloxazine) receptors or inhibition of adenosine uptake by dipyridamole. CSC or 8-PT abrogated the BRS(SNP) depressant effect of nicotine whereas other adenosinergic antagonists were without effect. Together, nicotine preferentially impairs reflex tachycardia via disruption of adenosine A(2A) receptor-mediated facilitation of reflex cardiac sympathoexcitation. Clinically, the attenuation by nicotine of compensatory sympathoexcitation may be detrimental in conditions such as hypothalamic defense response, posture changes, and ventricular rhythms.
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Affiliation(s)
- Mahmoud M El-Mas
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.
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Nassar N, Abdel-Rahman AA. Brainstem adenosine A1 receptor signaling masks phosphorylated extracellular signal-regulated kinase 1/2-dependent hypotensive action of clonidine in conscious normotensive rats. J Pharmacol Exp Ther 2008; 328:83-9. [PMID: 18849358 DOI: 10.1124/jpet.108.143883] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Central adenosine A(1) and A(2A) receptors mediate pressor and depressor responses, respectively. The adenosine subtype A(2A) receptor (A(2A)R)-evoked enhancement of phosphorylated extracellular signal-regulated kinase (pERK) 1/2 production in the rostral ventrolateral medulla (RVLM), a major neuroanatomical target for clonidine, contributes to clonidine-evoked hypotension, which is evident in conscious aortic barodenervated (ABD) but not in conscious sham-operated (SO) normotensive rats. We conducted pharmacological and cellular studies to test the hypothesis that the adenosine A(2A)R-mediated (pERK1/2-dependent) hypotensive action of clonidine is not expressed in SO rats because it is counterbalanced by fully functional central adenosine subtype A(1) receptor (A(1)R) signaling. We first demonstrated an inverse relationship between A(1)R expression in RVLM and clonidine-evoked hypotension in ABD and SO rats. The functional (pharmacological) relevance of the reduced expression of RVLM A(1)R in ABD rats was verified by the smaller dose-dependent pressor responses elicited by the selective A(1)R agonist N(6)-cyclopentyladenosine in ABD versus SO rats. It is important that after selective blockade of central A(1)R with 8-cyclopentyl-1,3-dipropylxanthine in conscious SO rats, clonidine lowered blood pressure and significantly increased neuronal pERK1/2 in the RVLM. In contrast, central A(1)R blockade had no influence on the hypotensive response or the increase in RVLM pERK1/2 elicited by clonidine in ABD rats. These findings support the hypothesis that central adenosine A(1)R signaling opposes the adenosine A(2A)R-mediated (pERK1/2-dependent) hypotensive response and yield insight into a cellular mechanism that explains the absence of clonidine-evoked hypotension in conscious normotensive rats.
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Affiliation(s)
- Noha Nassar
- Department of Pharmacology and Toxicology, School of Medicine, East Carolina University, Greenville, NC 27858, USA
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Maione S, de Novellis V, Cappellacci L, Palazzo E, Vita D, Luongo L, Stella L, Franchetti P, Marabese I, Rossi F, Grifantini M. The antinociceptive effect of 2-chloro-2'-C-methyl-N6-cyclopentyladenosine (2'-Me-CCPA), a highly selective adenosine A1 receptor agonist, in the rat. Pain 2007; 131:281-292. [PMID: 17317007 DOI: 10.1016/j.pain.2007.01.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 01/03/2007] [Accepted: 01/10/2007] [Indexed: 11/26/2022]
Abstract
This study was undertaken in order to investigate the effect of 2-chloro-2'-C-methyl-N(6)-cyclopentyladenosine (2'-Me-CCPA), a potent and highly selective adenosine A(1) receptor agonist, on nociceptive responses and on the ongoing or tail flick-related changes of rostral ventromedial medulla (RVM) ON- and OFF-cell activities. Systemic administrations of 2'-Me-CCPA (2.5-5 mg/kg, i.p.) reduced the nociceptive response in the plantar and formalin tests, in a way prevented by DPCPX (3 mg/kg, i.p.), a selective A(1) receptor antagonist. Similarly, intra-periaqueductal grey (PAG) 2'-Me-CCPA (0.5-1-2 nmol/rat) reduced pain behaviour in the plantar and formalin tests, in a way inhibited by DPCPX (0.5 nmol/rat). Moreover, when administered systemically (2.5-5 mg/kg, i.p.) or intra-PAG (0.5-1 nmol/rat) 2'-Me-CCPA increased the tail flick latencies, delayed the tail flick-related onset of the ON-cell burst and decreased the duration of the OFF-cell pause in a dose dependent manner. Furthermore, it decreased RVM ON-cell and increased OFF-cell ongoing activities. The in vivo electrophysiological effects were all prevented by DPCPX (0.5 nmol/rat). This study confirms the role of adenosine A(1) receptors in modulating pain and suggests a critical involvement of these receptors within PAG-RVM descending pathway for the processing of pain.
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Affiliation(s)
- S Maione
- Department of Experimental Medicine, Second University of Naples, 80138 Naples, Italy Department of Chemical Sciences, University of Camerino, 62032 Camerino, Italy
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12
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Peng SC, Ho CM, Ho ST, Tsai SK, Su CK. The role of intraspinal adenosine A1 receptors in sympathetic regulation. Eur J Pharmacol 2004; 492:49-55. [PMID: 15145705 DOI: 10.1016/j.ejphar.2004.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2003] [Revised: 03/24/2004] [Accepted: 04/01/2004] [Indexed: 11/28/2022]
Abstract
Using a splanchnic nerve-spinal cord preparation in vitro, we have previously demonstrated that tonic sympathetic activity is generated from the thoracic spinal cord. Here, we sought to determine if adenosine receptors play a role in modulating this spinally generated sympathetic activity. Various adenosine analogs were applied. N6-Cyclopentyladenosine (CPA, adenosine A1 receptor agonist) and 5'-N-ethylcarboxamidoadenosine (NECA, adenosine A1/A2 receptor agonist) reduced, while N6-[2-(4-aminophenyl)ethyl]adenosine (APNEA, non-selective adenosine A3 receptor agonist) did not alter sympathetic activity. The inhibitory effect of CPA or NECA on sympathetic activity was reversed by 8-cyclopentyltheophylline (CPT, adenosine A1 receptor antagonist) or abolished by CPT pretreatment. In the presence of 3,7-dimethyl-1-propargylxanthine (DMPX, adenosine A2 receptor antagonist), sympathetic activity was still reduced by CPA or NECA. Sympathetic activities were not changed by applications of the more selective adenosine A2 or A3 receptor agonists or antagonists, including 4-[2-[[6-amino-9-(N-ethyl-beta-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid (CGS21680), 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM241385), 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Chloro-IB-MECA), and 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS1191). These findings exclude a possible involvement of A2 or A3 receptors in sympathetic regulation at the spinal levels. Interestingly, CPT alone did not affect sympathetic activity, suggesting that adenosine A1 receptors are endogenously quiescent under our experimental conditions. We conclude that intraspinal adenosine A1 receptors may down-regulate sympathetic outflow and serve as a part of the scheme for neuroprotection.
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Affiliation(s)
- Shu-Chun Peng
- Institute of Biomedical Sciences, Academia Sinica, Taiwan
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Kang MJ, Park MS, Shin IC, Koh HC. Modification of cardiovascular response of posterior hypothalamic adenosine A(2) receptor stimulation by adenylate cylase, guanylate cyclase and by K(ATP) channel blockade in anesthetized rats. Neurosci Lett 2003; 344:57-61. [PMID: 12781921 DOI: 10.1016/s0304-3940(03)00402-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cardiovascular inhibitory effects induced by posterior hypothalamic adenosine A(2) receptors and their modulation by nitric oxide were suggested by our previous report. In this experiment, we examined the modulation of cardiovascular effects of adenosine A(2) receptor stimulation by adenylate cyclase, guanylate cyclase and ATP-sensitive K(+) channel in the posterior hypothalamus. Posterior hypothalamic injection of drugs was performed in anesthetized, artificially ventilated male Sprague-Dawley rats. Injection of adenosine A(2) receptor agonist 5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA; 1, 2 and 5 nmol) produced a dose-dependent decrease of blood pressure and heart rate. Pretreatment with adenosine A(2) receptor antagonist 3,7-dimethyl-1-propargylxanthine (10 nmol) blocked the depressor and bradycardiac effects of CPCA (5 nmol). Pretreatments with adenylate cyclase inhibitor MDL-12330 (10 nmol) and guanylate cyclase inhibitor LY-83583 (5 nmol) attenuated the depressor and bradycardiac effects of CPCA (5 nmol). In addition, pretreatment with ATP-sensitive K(+) channel blocker glipizide (20 nmol) attenuated the depressor and bradycardiac responses of CPCA (5 nmol). These results suggest that posterior hypothalamic adenosine A(2) receptors play an inhibitory role in the central cardiovascular regulation and that both adenylate cyclase and guanylate cyclase mediate the depressor and bradycardiac actions of adenosine A(2) receptors. Also, ATP-sensitive K(+) channel mediates the posterior hypothalamic cardiovascular regulations of adenosine A(2) receptors.
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Affiliation(s)
- Min Jeong Kang
- Department of Pharmacology, College of Medicine, Hanyang University, 17 Haengdang-Dong, Sungdong-Ku, Seoul 133-791, South Korea
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14
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Song MS, Shin KA, Kang JS, Lee CH, Shin IC, Lee SJ, Koh HC. The involvement of nitric oxide on the adenosine A(2) receptor-induced cardiovascular inhibitory responses in the posterior hypothalamus of rats. Neurosci Lett 2002; 326:41-5. [PMID: 12052534 DOI: 10.1016/s0304-3940(02)00290-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study was performed to investigate the putative relationship between nitric oxide (NO) and adenosine A(2) receptors on central cardiovascular regulation in the posterior hypothalamus of rats. Posterior hypothalamic injection of drugs was performed in anesthetized, artificially ventilated male Sprague-Dawley rats. Injection of adenosine A(2) receptor agonist 5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA; 1, 2 and 5 nmol) produced a dose-dependent decrease of blood pressure and heart rate. Pretreatment with adenosine A(2) receptor antagonist 3,7-dimethyl-1-propargylxanthine (10 nmol) blocked the depressor and bradycardiac effects of CPCA (5 nmol). Pretreatment with soluble guanylate cyclase inhibitor LY-83,583 (5 nmol) attenuated the depressor and bradycardiac effects of CPCA (5 nmol). In addition, pretreatment with NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (40 nmol) attenuated the depressor and bradycardiac responses of CPCA (5 nmol). These results suggest that adenosine A(2) receptor in the posterior hypothalamus plays an inhibitory role in central cardiovascular regulation and that NO participates in the inhibitory response induced by adenosine A(2) receptor stimulation in the posterior hypothalamus.
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Affiliation(s)
- Man Sung Song
- Department of Pharmacology, College of Medicine, Hanyang University, 17 Haengdang-Dong, Sungdong-Ku, Seoul 133-791, South Korea
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15
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Abstract
Snake envenomation employs three well integrated strategies: prey immobilization via hypotension, prey immobilization via paralysis, and prey digestion. Purines (adenosine, guanosine and inosine) evidently play a central role in the envenomation strategies of most advanced snakes. Purines constitute the perfect multifunctional toxins, participating simultaneously in all three envenomation strategies. Because they are endogenous regulatory compounds in all vertebrates, it is impossible for any prey organism to develop resistance to them. Purine generation from endogenous precursors in the prey explains the presence of many hitherto unexplained enzyme activities in snake venoms: 5'-nucleotidase, endonucleases (including ribonuclease), phosphodiesterase, ATPase, ADPase, phosphomonoesterase, and NADase. Phospholipases A(2), cytotoxins, myotoxins, and heparinase also participate in purine liberation, in addition to their better known functions. Adenosine contributes to prey immobilization by activation of neuronal adenosine A(1) receptors, suppressing acetylcholine release from motor neurons and excitatory neurotransmitters from central sites. It also exacerbates venom-induced hypotension by activating A(2) receptors in the vasculature. Adenosine and inosine both activate mast cell A(3) receptors, liberating vasoactive substances and increasing vascular permeability. Guanosine probably contributes to hypotension, by augmenting vascular endothelial cGMP levels via an unknown mechanism. Novel functions are suggested for toxins that act upon blood coagulation factors, including nitric oxide production, using the prey's carboxypeptidases. Leucine aminopeptidase may link venom hemorrhagic metalloproteases and endogenous chymotrypsin-like proteases with venom L-amino acid oxidase (LAO), accelerating the latter. The primary function of LAO is probably to promote prey hypotension by activating soluble guanylate cyclase in the presence of superoxide dismutase. LAO's apoptotic activity, too slow to be relevant to prey capture, is undoubtedly secondary and probably serves principally a digestive function. It is concluded that the principal function of L-type Ca(2+) channel antagonists and muscarinic toxins, in Dendroaspis venoms, and acetylcholinesterase in other elapid venoms, is to promote hypotension. Venom dipeptidyl peptidase IV-like enzymes probably also contribute to hypotension by destroying vasoconstrictive peptides such as Peptide YY, neuropeptide Y and substance P. Purines apparently bind to other toxins which then serve as molecular chaperones to deposit the bound purines at specific subsets of purine receptors. The assignment of pharmacological activities such as transient neurotransmitter suppression, histamine release and antinociception, to a variety of proteinaceous toxins, is probably erroneous. Such effects are probably due instead to purines bound to these toxins, and/or to free venom purines.
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Affiliation(s)
- Steven D Aird
- Laboratório de Toxinas Naturais, Universidade Estadual do Ceará, Avenida Paranjana, 1700, Itaperí, 60740-000, Fortaleza, CE, Brazil.
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van Muijlwijk-Koezen JE, Timmerman H, Ijzerman AP. The adenosine A3 receptor and its ligands. PROGRESS IN MEDICINAL CHEMISTRY 2002; 38:61-113. [PMID: 11774799 DOI: 10.1016/s0079-6468(08)70092-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Affiliation(s)
- J E van Muijlwijk-Koezen
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Department of Pharmacochemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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17
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Lee TM, Su SF, Chou TF, Tsai CH. Effect of pravastatin on myocardial protection during coronary angioplasty and the role of adenosine. Am J Cardiol 2001; 88:1108-13. [PMID: 11703953 DOI: 10.1016/s0002-9149(01)02043-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pravastatin has been shown, in an experimental model of ischemia reperfusion, to increase adenosine levels, which exert a potent and protective effect on the heart. The purpose of this study was to investigate whether pravastatin can provide cardioprotection by increased production of adenosine in patients undergoing coronary angioplasty, a clinical model of ischemia reperfusion. Thirty-five hyperlipidemic patients who underwent elective angioplasty for a major epicardial coronary artery were randomly allocated to either 3-month pravastatin or placebo before catheterization. In the placebo group, the mean ST-segment shift during the second balloon inflation was similar that observed during the first inflation, whereas in the preconditioned patients, the shift was significantly less, which is consistent with ischemic preconditioning. In the pravastatin-treated patients, the changes of ST-segment shift were similar between the first and second balloon inflations. In contrast, the patients who received aminophylline developed higher ST-segment shifts during the first and second inflations than those in the pravastatin-treated group alone. Measurements of chest pain score and myocardial lactate extraction ratios during inflation mirrored those of the ST-segment shift. The present study demonstrates that administration of pravastatin results in a significant gain in tolerance to ischemia during angioplasty. The effect of pravastatin was abolished by aminophylline, suggesting that the cardioprotective effect of pravastatin may result from activation of adenosine receptors.
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Affiliation(s)
- T M Lee
- Department of Internal Medicine, Cardiology Section, Taiwan University College of Medicine, National Taiwan University Hospital, Taipei, Taiwan
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18
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Nieri P, Martinotti E, Calderone V, Breschi MC. Adenosine-mediated hypotension in in vivo guinea-pig: receptors involved and role of NO. Br J Pharmacol 2001; 134:745-52. [PMID: 11606314 PMCID: PMC1572997 DOI: 10.1038/sj.bjp.0704301] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Adenosine produced a biphasic lowering of the mean BP with a drastic bradycardic effect at the highest doses. The first phase hypotensive response was significantly reduced by the nitric oxide (NO) synthase inhibitor L-NAME. 2. The A(2a)/A(2b) agonist NECA produced hypotensive and bradycardic responses similar to those elicited by adenosine, which were not significantly modified by the A(2b) antagonist enprofylline. 3. The A(2a) agonist CGS 21680 did not significantly influence basal HR while induced a hypotensive response antagonized by the A(2a) selective antagonist ZM 241385, and reduced by both L-NAME and the guanylate cyclase inhibitor methylene blue. 4. The A(1) agonist R-PIA showed a dose-dependent decrease in BP with a drastic decrease in HR at the highest doses. The A(1) selective antagonist DPCPX significantly reduced the bradycardic activity and also the hypotensive responses obtained with the lowest doses while it increased those obtained with the highest ones. 5. The A(1)/A(3) agonist APNEA, in the presence of the xanthinic non-selective antagonist 8-pSPT, maintained a significant hypotensive, but not bradycardic, activity, not abolished by the histamine antagonist diphenhydramine. 6. The selective A(3) agonist IB-MECA revealed a weak hypotensive and bradycardic effect, but only at the highest doses. 7. In conclusion, in the systemic cardiovascular response to adenosine two major components may be relevant: an A(2a)- and NO-mediated hypotension, and a bradycardic effect with a consequent hypotension, via atypical A(1) receptors. Finally, an 8-pSPT-resistant hypotensive response not attributable to A(3) receptor-stimulation or to release of histamine by mastocytes or other immune cells was observed.
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Affiliation(s)
- P Nieri
- Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, Via Bonanno 6-56126, PISA, Italy.
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