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Yashiro T, Ogata H, Zaidi SF, Lee J, Hayashi S, Yamamoto T, Kadowaki M. Pathophysiological Roles of Neuro-Immune Interactions between Enteric Neurons and Mucosal Mast Cells in the Gut of Food Allergy Mice. Cells 2021; 10:1586. [PMID: 34201851 PMCID: PMC8305700 DOI: 10.3390/cells10071586] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 12/20/2022] Open
Abstract
Recently, the involvement of the nervous system in the pathology of allergic diseases has attracted increasing interest. However, the precise pathophysiological role of enteric neurons in food allergies has not been elucidated. We report the presence of functional high-affinity IgE receptors (FcεRIs) in enteric neurons. FcεRI immunoreactivities were observed in approximately 70% of cholinergic myenteric neurons from choline acetyltransferase-eGFP mice. Furthermore, stimulation by IgE-antigen elevated intracellular Ca2+ concentration in isolated myenteric neurons from normal mice, suggesting that FcεRIs are capable of activating myenteric neurons. Additionally, the morphological investigation revealed that the majority of mucosal mast cells were in close proximity to enteric nerve fibers in the colonic mucosa of food allergy mice. Next, using a newly developed coculture system of isolated myenteric neurons and mucosal-type bone-marrow-derived mast cells (mBMMCs) with a calcium imaging system, we demonstrated that the stimulation of isolated myenteric neurons by veratridine caused the activation of mBMMCs, which was suppressed by the adenosine A3 receptor antagonist MRE 3008F20. Moreover, the expression of the adenosine A3 receptor gene was detected in mBMMCs. Therefore, in conclusion, it is suggested that, through interaction with mucosal mast cells, IgE-antigen-activated myenteric neurons play a pathological role in further exacerbating the pathology of food allergy.
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Affiliation(s)
- Tomoe Yashiro
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
| | - Hanako Ogata
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
| | - Syed Faisal Zaidi
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
- Department of Pharmacology, School of Medicine, Batterjee Medical College for Sciences and Technology, Jeddah 21442, Saudi Arabia
| | - Jaemin Lee
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
| | - Shusaku Hayashi
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
| | - Takeshi Yamamoto
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
| | - Makoto Kadowaki
- Division of Gastrointestinal Pathophysiology, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan; (T.Y.); (H.O.); (S.F.Z.); (J.L.); (S.H.); (T.Y.)
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Kutryb-Zajac B, Mierzejewska P, Slominska EM, Smolenski RT. Therapeutic Perspectives of Adenosine Deaminase Inhibition in Cardiovascular Diseases. Molecules 2020; 25:molecules25204652. [PMID: 33053898 PMCID: PMC7587364 DOI: 10.3390/molecules25204652] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023] Open
Abstract
Adenosine deaminase (ADA) is an enzyme of purine metabolism that irreversibly converts adenosine to inosine or 2'deoxyadenosine to 2'deoxyinosine. ADA is active both inside the cell and on the cell surface where it was found to interact with membrane proteins, such as CD26 and adenosine receptors, forming ecto-ADA (eADA). In addition to adenosine uptake, the activity of eADA is an essential mechanism that terminates adenosine signaling. This is particularly important in cardiovascular system, where adenosine protects against endothelial dysfunction, vascular inflammation, or thrombosis. Besides enzymatic function, ADA protein mediates cell-to-cell interactions involved in lymphocyte co-stimulation or endothelial activation. Furthermore, alteration in ADA activity was demonstrated in many cardiovascular pathologies such as atherosclerosis, myocardial ischemia-reperfusion injury, hypertension, thrombosis, or diabetes. Modulation of ADA activity could be an important therapeutic target. This work provides a systematic review of ADA activity and anchoring inhibitors as well as summarizes the perspectives of their therapeutic use in cardiovascular pathologies associated with increased activity of ADA.
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Affiliation(s)
- Barbara Kutryb-Zajac
- Correspondence: (B.K.-Z); (R.T.S.); Tel.: +48-58-349-14-64 (B.K.-Z.); +48-58-349-14-60 (R.T.S.)
| | | | | | - Ryszard T. Smolenski
- Correspondence: (B.K.-Z); (R.T.S.); Tel.: +48-58-349-14-64 (B.K.-Z.); +48-58-349-14-60 (R.T.S.)
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de Oliveira M, Mathias LS, de Sibio MT, Noronha-Matos JB, Costa MA, Nogueira CR, Correia-de-Sá P. Pitfalls and challenges of the purinergic signaling cascade in obesity. Biochem Pharmacol 2020; 182:114214. [PMID: 32905795 DOI: 10.1016/j.bcp.2020.114214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 12/15/2022]
Abstract
Obesity is a worldwide health problem which have reached pandemic proportions, now also including low and middle-income countries. Excessive or abnormal fat deposition in the abdomen especially in the visceral compartment is tightly associated with a high metabolic risk for arterial hypertension, type II diabetes, cardiovascular diseases, musculoskeletal disorders (especially articular degeneration) and some cancers. Contrariwise, accumulation of fat in the subcutaneous compartment has been associated with a neutral metabolic impact, favoring a lower risk of insulin resistance. Obesity results more often from an avoidable imbalance between food consumption and energy expenditure. There are several recommended strategies for dealing with obesity, including pharmacological therapies, but their success remains incomplete and may not compensate the associated adverse effects. Purinergic signaling operated by ATP and its metabolite, adenosine, has attracted increasing attention in obesity. The extracellular levels of purines often reflect the energy status of a given cell population. Adenine nucleotides and nucleosides fine tuning control adipogenesis and mature adipocytes function via the activation of P2 and P1 purinoceptors, respectively. These features make the purinergic signaling cascade a putative target for therapeutic intervention in obesity and related metabolic syndromes. There are, however, gaps in our knowledge regarding the role of purines in adipocyte precursors differentiation and mature adipocytes functions, as well as their impact among distinct adipose tissue deposits (e.g. white vs. brown, visceral vs. subcutaneous), which warrants further investigations before translation to clinical trials can be made.
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Affiliation(s)
- Miriane de Oliveira
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - Lucas Solla Mathias
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - Maria Teresa de Sibio
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - José Bernardo Noronha-Matos
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - Maria Adelina Costa
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Departamento de Química, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP)
| | - Célia Regina Nogueira
- São Paulo State University (UNESP), Botucatu Medical School, District of Rubião Jr, s/n, 18618-000, Botucatu, São Paulo, Brazil
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP); Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP).
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Cheng X, Cheng G, Xing X, Yin C, Cheng Y, Zhou X, Jiang S, Tao F, Deng H, Li Z. Controlled release of adenosine from core-shell nanofibers to promote bone regeneration through STAT3 signaling pathway. J Control Release 2020; 319:234-245. [DOI: 10.1016/j.jconrel.2019.12.048] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/16/2019] [Accepted: 12/28/2019] [Indexed: 12/13/2022]
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Bagheri S, Saboury AA, Haertlé T. Adenosine deaminase inhibition. Int J Biol Macromol 2019; 141:1246-1257. [PMID: 31520704 DOI: 10.1016/j.ijbiomac.2019.09.078] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/18/2022]
Abstract
Adenosine deaminase is a critical enzyme in purine metabolism that regulates intra and extracellular adenosine concentrations by converting it to inosine. Adenosine is an important purine that regulates numerous physiological functions by interacting with its receptors. Adenosine and consequently adenosine deaminase can have pro or anti-inflammatory effects on tissues depending on how much time has passed from the start of the injury. In addition, an increase in adenosine deaminase activity has been reported for various diseases and the significant effect of deaminase inhibition on the clinical course of different diseases has been reported. However, the use of inhibitors is limited to only a few medical indications. Data on the increase of adenosine deaminase activity in different diseases and the impact of its inhibition in various cases have been collected and are discussed in this review. Overall, the evidence shows that many studies have been done to introduce inhibitors, however, in vivo studies have been much less than in vitro, and often have not been expanded for clinical use.
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Affiliation(s)
- S Bagheri
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - A A Saboury
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
| | - T Haertlé
- Institut National de la Recherche Agronomique, Nantes, France
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The ecto-enzymes CD73 and adenosine deaminase modulate 5'-AMP-derived adenosine in myofibroblasts of the rat small intestine. Purinergic Signal 2018; 14:409-421. [PMID: 30269308 DOI: 10.1007/s11302-018-9623-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 08/21/2018] [Indexed: 12/12/2022] Open
Abstract
Adenosine is a versatile signaling molecule recognized to physiologically influence gut motor functions. Both the duration and magnitude of adenosine signaling in enteric neuromuscular function depend on its availability, which is regulated by the ecto-enzymes ecto-5'-nucleotidase (CD73), alkaline phosphatase (AP), and ecto-adenosine deaminase (ADA) and by dipyridamole-sensitive equilibrative transporters (ENTs). Our purpose was to assess the involvement of CD73, APs, ecto-ADA in the formation of AMP-derived adenosine in primary cultures of ileal myofibroblasts (IMFs). IMFs were isolated from rat ileum longitudinal muscle segments by means of primary explant technique and identified by immunofluorescence staining for vimentin and α-smooth muscle actin. IMFs confluent monolayers were exposed to exogenous 5'-AMP in the presence or absence of CD73, APs, ecto-ADA, or ENTs inhibitors. The formation of adenosine and its metabolites in the IMFs medium was monitored by high-performance liquid chromatography. The distribution of CD73 and ADA in IMFs was detected by confocal immunocytochemistry and qRT-PCR. Exogenous 5'-AMP was rapidly cleared being almost undetectable after 60-min incubation, while adenosine levels significantly increased. Treatment of IMFs with CD73 inhibitors markedly reduced 5'-AMP clearance whereas ADA blockade or inhibition of both ADA and ENTs prevented adenosine catabolism. By contrast, inhibition of APs did not affect 5'-AMP metabolism. Immunofluorescence staining and qRT-PCR analysis confirmed the expression of CD73 and ADA in IMFs. Overall, our data show that in IMFs an extracellular AMP-adenosine pathway is functionally active and among the different enzymatic pathways regulating extracellular adenosine levels, CD73 and ecto-ADA represent the critical catabolic pathway.
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7
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Vieira C, Ferreirinha F, Magalhães-Cardoso MT, Silva I, Marques P, Correia-de-Sá P. Post-inflammatory Ileitis Induces Non-neuronal Purinergic Signaling Adjustments of Cholinergic Neurotransmission in the Myenteric Plexus. Front Pharmacol 2017; 8:811. [PMID: 29167643 PMCID: PMC5682326 DOI: 10.3389/fphar.2017.00811] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/26/2017] [Indexed: 12/11/2022] Open
Abstract
Uncoupling between ATP overflow and extracellular adenosine formation changes purinergic signaling in post-inflammatory ileitis. Adenosine neuromodulation deficits were ascribed to feed-forward inhibition of ecto-5′-nucleotidase/CD73 by high extracellular adenine nucleotides in the inflamed ileum. Here, we hypothesized that inflammation-induced changes in cellular density may also account to unbalance the release of purines and their influence on [3H]acetylcholine release from longitudinal muscle-myenteric plexus preparations of the ileum of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-treated rats. The population of S100β-positive glial cells increase, whereas Ano-1-positive interstitial cells of Cajal (ICCs) diminished, in the ileum 7-days after the inflammatory insult. In the absence of changes in the density of VAChT-positive cholinergic nerves detected by immunofluorescence confocal microscopy, the inflamed myenteric plexus released smaller amounts of [3H]acetylcholine which also became less sensitive to neuronal blockade by tetrodotoxin (1 μM). Instead, [3H]acetylcholine release was attenuated by sodium fluoroacetate (5 mM), carbenoxolone (10 μM) and A438079 (3 μM), which prevent activation of glial cells, pannexin-1 hemichannels and P2X7 receptors, respectively. Sodium fluoroacetate also decreased ATP overflow without significantly affecting the extracellular adenosine levels, thus indicating that surplus ATP release parallels reactive gliosis in post-inflammatory ileitis. Conversely, loss of ICCs may explain the lower amounts of adenosine detected in TNBS-treated preparations, since blockade of Cav3 (T-type) channels existing in ICCs with mibefradil (3 μM) or inhibition of the equilibrative nucleoside transporter 1 with dipyridamole (0.5 μM), both decreased extracellular adenosine. Data indicate that post-inflammatory ileitis operates a shift on purinergic neuromodulation reflecting the upregulation of ATP-releasing enteric glial cells and the depletion of ICCs accounting for decreased adenosine overflow via equilibrative nucleoside transporters.
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Affiliation(s)
- Cátia Vieira
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Fátima Ferreirinha
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Maria T Magalhães-Cardoso
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Isabel Silva
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Patrícia Marques
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
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Silva I, Costa AF, Moreira S, Ferreirinha F, Magalhães-Cardoso MT, Calejo I, Silva-Ramos M, Correia-de-Sá P. Inhibition of cholinergic neurotransmission by β 3-adrenoceptors depends on adenosine release and A 1-receptor activation in human and rat urinary bladders. Am J Physiol Renal Physiol 2017; 313:F388-F403. [PMID: 28446460 DOI: 10.1152/ajprenal.00392.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 12/12/2022] Open
Abstract
The direct detrusor relaxant effect of β3-adrenoceptor agonists as a primary mechanism to improve overactive bladder symptoms has been questioned. Among other targets, activation of β3-adrenoceptors downmodulate nerve-evoked acetylcholine (ACh) release, but there is insufficient evidence for the presence of these receptors on bladder cholinergic nerve terminals. Our hypothesis is that adenosine formed from the catabolism of cyclic AMP in the detrusor may act as a retrograde messenger via prejunctional A1 receptors to explain inhibition of cholinergic activity by β3-adrenoceptors. Isoprenaline (1 µM) decreased [3H]ACh release from stimulated (10 Hz, 200 pulses) human (-47 ± 5%) and rat (-38 ± 1%) detrusor strips. Mirabegron (0.1 µM, -53 ± 8%) and CL316,243 (1 µM, -37 ± 7%) mimicked isoprenaline (1 µM) inhibition, and their effects were prevented by blocking β3-adrenoceptors with L748,337 (30 nM) and SR59230A (100 nM), respectively, in human and rat detrusor. Mirabegron and isoprenaline increased extracellular adenosine in the detrusor. Blockage of A1 receptors with 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 100 nM) or the equilibrative nucleoside transporters (ENT) with dipyridamole (0.5 µM) prevented mirabegron and isoprenaline inhibitory effects. Dipyridamole prevented isoprenaline-induced adenosine outflow from the rat detrusor, and this effect was mimicked by the ENT1 inhibitor, S-(4-nitrobenzyl)-6-thioinosine (NBTI, 30 µM). Cystometry recordings in anesthetized rats demonstrated that SR59230A, DPCPX, dipyridamole, and NBTI reversed the decrease in the voiding frequency caused by isoprenaline (0.1-1,000 nM). Data suggest that inhibition of cholinergic neurotransmission by β3-adrenoceptors results from adenosine release via equilibrative nucleoside transporters and prejunctional A1-receptor stimulation in human and rat urinary bladder.
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Affiliation(s)
- Isabel Silva
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
| | - Ana Filipa Costa
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
| | - Sílvia Moreira
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
| | - Fátima Ferreirinha
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
| | - Maria Teresa Magalhães-Cardoso
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
| | - Isabel Calejo
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
| | - Miguel Silva-Ramos
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal.,Serviço de Urologia, Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Universidade do Porto, Porto, Portugal; .,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal; and
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Silva-Ramos M, Silva I, Faria M, Magalhães-Cardoso MT, Correia J, Ferreirinha F, Correia-de-Sá P. Impairment of ATP hydrolysis decreases adenosine A1 receptor tonus favoring cholinergic nerve hyperactivity in the obstructed human urinary bladder. Purinergic Signal 2015; 11:595-606. [PMID: 26521170 DOI: 10.1007/s11302-015-9478-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022] Open
Abstract
This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [(3)H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n = 31) and control organ donors (n = 23). The neurogenic release of ATP and [(3)H]ACh was higher (P < 0.05) in detrusor strips from BPH patients. The extracellular hydrolysis of ATP and, subsequent, adenosine formation was slower (t (1/2) 73 vs. 36 min, P < 0.05) in BPH detrusor strips. The A(1) receptor-mediated inhibition of evoked [(3)H]ACh release by adenosine (100 μM), NECA (1 μM), and R-PIA (0.3 μM) was enhanced in BPH bladders. Relaxation of detrusor contractions induced by acetylcholine required 30-fold higher concentrations of adenosine. Despite VAChT-positive cholinergic nerves exhibiting higher A(1) immunoreactivity in BPH bladders, the endogenous adenosine tonus revealed by adenosine deaminase is missing. Restoration of A1 inhibition was achieved by favoring (1) ATP hydrolysis with apyrase (2 U mL(-1)) or (2) extracellular adenosine accumulation with dipyridamole or EHNA, as these drugs inhibit adenosine uptake and deamination, respectively. In conclusion, reduced ATP hydrolysis leads to deficient adenosine formation and A(1) receptor-mediated inhibition of cholinergic nerve activity in the obstructed human bladder. Thus, we propose that pharmacological manipulation of endogenous adenosine levels and/or A(1) receptor activation might be useful to control bladder overactivity in BPH patients.
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Affiliation(s)
- M Silva-Ramos
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.,Serviço de Urologia, Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - I Silva
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - M Faria
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - M T Magalhães-Cardoso
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - J Correia
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - F Ferreirinha
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - P Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal. .,Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, R. Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.
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Cardoso AM, Schetinger MRC, Correia-de-Sá P, Sévigny J. Impact of ectonucleotidases in autonomic nervous functions. Auton Neurosci 2015; 191:25-38. [PMID: 26008223 DOI: 10.1016/j.autneu.2015.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 01/05/2023]
Abstract
Adenine and uracil nucleotides play key functions in the autonomic nervous system (ANS). For instance, ATP acts as a neurotransmitter, co-transmitter and neuromodulator in the ANS. The purinergic system encompasses (1) receptors that respond to extracellular purines, which are designated as P1 and P2 purinoceptors, (2) purine release and uptake, and (3) a cascade of enzymes that regulate the concentration of purines near the cell surface. Ectonucleotidases and adenosine deaminase (ADA) are enzymes responsible for the hydrolysis of ATP (and other nucleotides such as ADP, UTP, UDP, AMP) and adenosine, respectively. Accordingly, these enzymes are expected to play an important role in the control of neuro-effector transmission in tissues innervated by both the sympathetic and parasympathetic divisions of the ANS. Indeed, ectonucleotidases have the ability to either terminate P2 receptor responses initiated by nucleoside triphosphates (ATP and UTP), and/or to favor the activation of ADP (e.g. P2Y1,12,13) and UDP (e.g. P2Y6) and/or adenosine (P1) specific receptors. In addition, ectonucleotidases can also importantly protect some P2 receptors from desensitization (e.g. P2X1, P2Y1). In this review, we present the (putative) roles of ectonucleotidases and ADA in the ANS with a focus on their regulatory activity at neuro-effector junctions in the following tissues: heart, vas deferens, urinary bladder, salivary glands, blood vessels and the intestine. We also present their implication in nociceptive transmission.
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Affiliation(s)
- Andréia Machado Cardoso
- Post-Graduation Program in Toxicological Biochemistry, Department of Biochemistry and Molecular Biology of the Center of Natural and Exact Sciences of the Federal University of Santa Maria, Santa Maria Rio Grande do Sul, Brazil; Département de Microbiologie-Infectiologie et d'Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec G1V 0A6, Canada; Centre de Recherche du CHU de Québec - Université Laval, Québec G1V 4G2, Canada.
| | - Maria Rosa Chitolina Schetinger
- Post-Graduation Program in Toxicological Biochemistry, Department of Biochemistry and Molecular Biology of the Center of Natural and Exact Sciences of the Federal University of Santa Maria, Santa Maria Rio Grande do Sul, Brazil
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, MedInUP, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto (UP), 4050-313 Porto, Portugal
| | - Jean Sévigny
- Département de Microbiologie-Infectiologie et d'Immunologie, Faculté de Médecine, Université Laval, Québec City, Québec G1V 0A6, Canada; Centre de Recherche du CHU de Québec - Université Laval, Québec G1V 4G2, Canada.
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11
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Mutafova-Yambolieva VN, Durnin L. The purinergic neurotransmitter revisited: a single substance or multiple players? Pharmacol Ther 2014; 144:162-91. [PMID: 24887688 PMCID: PMC4185222 DOI: 10.1016/j.pharmthera.2014.05.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 12/20/2022]
Abstract
The past half century has witnessed tremendous advances in our understanding of extracellular purinergic signaling pathways. Purinergic neurotransmission, in particular, has emerged as a key contributor in the efficient control mechanisms in the nervous system. The identity of the purine neurotransmitter, however, remains controversial. Identifying it is difficult because purines are present in all cell types, have a large variety of cell sources, and are released via numerous pathways. Moreover, studies on purinergic neurotransmission have relied heavily on indirect measurements of integrated postjunctional responses that do not provide direct information for neurotransmitter identity. This paper discusses experimental support for adenosine 5'-triphosphate (ATP) as a neurotransmitter and recent evidence for possible contribution of other purines, in addition to or instead of ATP, in chemical neurotransmission in the peripheral, enteric and central nervous systems. Sites of release and action of purines in model systems such as vas deferens, blood vessels, urinary bladder and chromaffin cells are discussed. This is preceded by a brief discussion of studies demonstrating storage of purines in synaptic vesicles. We examine recent evidence for cell type targets (e.g., smooth muscle cells, interstitial cells, neurons and glia) for purine neurotransmitters in different systems. This is followed by brief discussion of mechanisms of terminating the action of purine neurotransmitters, including extracellular nucleotide hydrolysis and possible salvage and reuptake in the cell. The significance of direct neurotransmitter release measurements is highlighted. Possibilities for involvement of multiple purines (e.g., ATP, ADP, NAD(+), ADP-ribose, adenosine, and diadenosine polyphosphates) in neurotransmission are considered throughout.
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Affiliation(s)
| | - Leonie Durnin
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, United States
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12
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Serpa A, Sebastião AM, Cascalheira JF. Modulation of cGMP accumulation by adenosine A1 receptors at the hippocampus: influence of cGMP levels and gender. Eur J Pharmacol 2014; 744:83-90. [PMID: 25300679 DOI: 10.1016/j.ejphar.2014.09.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/31/2022]
Abstract
Adenosine A1 receptor is highly expressed in hippocampus where it inhibits neurotransmitter release and has neuroprotective activity. Similar actions are obtained by increasing cGMP concentration, but a clear link between adenosine A1 receptor and cGMP levels remains to be established. The present work aims to investigate if cGMP formation is modulated by adenosine A1 receptors at the hippocampus and if this effect is gender dependent. cGMP accumulation, induced by phosphodiesterases inhibitors Zaprinast (100 μM) and Bay 60-7550 (10 μM), and cAMP accumulation, induced by Forskolin (20 μM) and Rolipram (50 μM), were quantified in rat hippocampal slices using specific enzymatic immunoassays. N6-cyclopentyladenosine (CPA, 100 nM) alone failed to modify basal cGMP accumulation. However, the presence of adenosine deaminase (ADA, 2 U/ml) unmasked a CPA (0.03-300 nM) stimulatory effect on basal cGMP accumulation (EC50: 4.2±1.4 nM; Emax: 17±0.9%). ADA influence on CPA activity was specific for cGMP, since inhibition of cAMP accumulation by CPA was not affected by the presence of ADA, though ADA inhibited cAMP accumulation in the absence of CPA. Increasing cGMP accumulation, by about four-fold, with sodium nitroprusside (SNP, 100 μM) abolished the CPA (100 nM) effect on cGMP accumulation in males but did not modify the effect of CPA in female rats. This effect was reversed by 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX, 100 nM), indicating an adenosine A1 receptor mediated effect on cGMP accumulation. In conclusion, adenosine A1 receptors increase intracellular cGMP formation at hippocampus both in males and females under basal conditions, but only in females when cGMP levels are increased by SNP.
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Affiliation(s)
- André Serpa
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal
| | - Ana M Sebastião
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, University of Lisbon, Lisboa, Portugal; Unit of Neurosciences, Institute of Molecular Medicine, University of Lisbon, Lisboa, Portugal
| | - José F Cascalheira
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal; Department of Chemistry, University of Beira Interior, Covilhã, Portugal.
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Feed-forward inhibition of CD73 and upregulation of adenosine deaminase contribute to the loss of adenosine neuromodulation in postinflammatory ileitis. Mediators Inflamm 2014; 2014:254640. [PMID: 25210228 PMCID: PMC4152956 DOI: 10.1155/2014/254640] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 01/31/2023] Open
Abstract
Purinergic signalling is remarkably plastic during gastrointestinal inflammation. Thus, selective drugs targeting the “purinome” may be helpful for inflammatory gastrointestinal diseases. The myenteric neuromuscular transmission of healthy individuals is fine-tuned and controlled by adenosine acting on A2A excitatory receptors. Here, we investigated the neuromodulatory role of adenosine in TNBS-inflamed longitudinal muscle-myenteric plexus of the rat ileum. Seven-day postinflammation ileitis lacks adenosine neuromodulation, which may contribute to acceleration of gastrointestinal transit. The loss of adenosine neuromodulation results from deficient accumulation of the nucleoside at the myenteric synapse despite the fact that the increases in ATP release were observed. Disparity between ATP outflow and adenosine deficit in postinflammatory ileitis is ascribed to feed-forward inhibition of ecto-5′-nucleotidase/CD73 by high extracellular ATP and/or ADP. Redistribution of NTPDase2, but not of NTPDase3, from ganglion cell bodies to myenteric nerve terminals leads to preferential ADP accumulation from released ATP, thus contributing to the prolonged inhibition of muscle-bound ecto-5′-nucleotidase/CD73 and to the delay of adenosine formation at the inflamed neuromuscular synapse. On the other hand, depression of endogenous adenosine accumulation may also occur due to enhancement of adenosine deaminase activity. Both membrane-bound and soluble forms of ecto-5′-nucleotidase/CD73 and adenosine deaminase were detected in the inflamed myenteric plexus. These findings provide novel therapeutic targets for inflammatory gut motility disorders.
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14
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Burnstock G. Purinergic signalling in the gastrointestinal tract and related organs in health and disease. Purinergic Signal 2014; 10:3-50. [PMID: 24307520 PMCID: PMC3944042 DOI: 10.1007/s11302-013-9397-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/04/2023] Open
Abstract
Purinergic signalling plays major roles in the physiology and pathophysiology of digestive organs. Adenosine 5'-triphosphate (ATP), together with nitric oxide and vasoactive intestinal peptide, is a cotransmitter in non-adrenergic, non-cholinergic inhibitory neuromuscular transmission. P2X and P2Y receptors are widely expressed in myenteric and submucous enteric plexuses and participate in sympathetic transmission and neuromodulation involved in enteric reflex activities, as well as influencing gastric and intestinal epithelial secretion and vascular activities. Involvement of purinergic signalling has been identified in a variety of diseases, including inflammatory bowel disease, ischaemia, diabetes and cancer. Purinergic mechanosensory transduction forms the basis of enteric nociception, where ATP released from mucosal epithelial cells by distension activates nociceptive subepithelial primary afferent sensory fibres expressing P2X3 receptors to send messages to the pain centres in the central nervous system via interneurons in the spinal cord. Purinergic signalling is also involved in salivary gland and bile duct secretion.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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15
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Zoppellaro C, Bin A, Brun P, Banzato S, Macchi V, Castagliuolo I, Giron MC. Adenosine-mediated enteric neuromuscular function is affected during herpes simplex virus type 1 infection of rat enteric nervous system. PLoS One 2013; 8:e72648. [PMID: 24015268 PMCID: PMC3754913 DOI: 10.1371/journal.pone.0072648] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 07/11/2013] [Indexed: 02/06/2023] Open
Abstract
Adenosine plays an important role in regulating intestinal motility and inflammatory processes. Previous studies in rodent models have demonstrated that adenosine metabolism and signalling are altered during chronic intestinal inflammatory diseases. However, the involvement of the adenosinergic system in the pathophysiology of gut dysmotility associated to a primary neurodysfunction is still unclear. Recently, we showed that the neurotropic Herpes simplex virus type-1 (HSV-1), orally inoculated to rodents, infects the rat enteric nervous system (ENS) and affects gut motor function without signs of systemic infection. In this study we examined whether changes in purinergic metabolism and signaling occur during permanent HSV-1 infection of rat ENS. Using isolated organ bath assays, we found that contraction mediated by adenosine engagement of A1 or A2A receptors was impaired at 1 and 6 weeks post-viral administration. Immunofluorescence studies revealed that viral infection of ENS led to a marked redistribution of adenosine receptors: A1 and A2B receptors were confined to the muscle layers whereas A2A and A3 receptors were expressed mainly in the myenteric plexus. Viral-induced ENS neurodysfunction influenced adenosine metabolism by increasing adenosine deaminase and CD73 levels in longitudinal muscle-myenteric plexus with no sign of frank inflammation. This study provides the first evidence for involvement of the adenosinergic system during HSV-1 infection of the ENS. As such, this may represent a valid therapeutic target for modulating gut contractility associated to a primary neurodysfunction.
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Affiliation(s)
- Chiara Zoppellaro
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Anna Bin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Paola Brun
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Serena Banzato
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Veronica Macchi
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | | | - Maria Cecilia Giron
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
- * E-mail:
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16
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Vieira C, Ferreirinha F, Silva I, Duarte-Araújo M, Correia-de-Sá P. Localization and function of adenosine receptor subtypes at the longitudinal muscle--myenteric plexus of the rat ileum. Neurochem Int 2011; 59:1043-55. [PMID: 21924311 DOI: 10.1016/j.neuint.2011.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 08/11/2011] [Accepted: 08/22/2011] [Indexed: 10/17/2022]
Abstract
Adenosine plays a dual role on acetylcholine (ACh) release from myenteric motoneurons via the activation of high-affinity inhibitory A₁ and facilitatory A(2A) receptors. The therapeutic potential of adenosine-related compounds for controlling intestinal motility and inflammation, prompted us to investigate further the role of low-affinity adenosine receptors, A(2B) and A₃, on electrically-evoked (5 Hz, 200 pulses) [³H]ACh release from myenteric neurons. Immunolocalization studies showed that A(2B) receptors exhibit a pattern of distribution similar to the glial cell marker, GFAP. Regarding A₁ and A₃ receptors, they are mainly distributed to cell bodies of ganglionic myenteric neurons, whereas A(2A) receptors are localized predominantly on cholinergic nerve terminals. Using selective antagonists (DPCPX, ZM241385 and MRS1191), data indicate that modulation of evoked [³H]ACh release is balanced through tonic activation of inhibitory (A₁) and facilitatory (A(2A) and A₃) receptors by endogenous adenosine. The selective A(2B) receptor antagonist, PSB603, alone was devoid of effect and failed to modify the inhibitory effect of NECA. The A₃ receptor agonist, 2-Cl-IB MECA (1-10 nM), concentration-dependently increased the release of [³H]ACh. The effect of 2-Cl-IB MECA was attenuated by MRS1191 and by ZM241385, which selectively block respectively A₃ and A(2A) receptors. In contrast to 2-Cl-IB MECA, activation of A(2A) receptors with CGS21680C attenuated nicotinic facilitation of ACh release induced by focal depolarization of myenteric nerve terminals in the presence of tetrodotoxin. Tandem localization of excitatory A₃ and A(2A) receptors along myenteric neurons explains why stimulation of A₃ receptors (with 2-Cl-IB MECA) on nerve cell bodies acts cooperatively with prejunctional facilitatory A(2A) receptors to up-regulate acetylcholine release. The results presented herein consolidate and expand the current understanding of adenosine receptor distribution and function in the myenteric plexus of the rat ileum, and should be taken into consideration for data interpretation regarding the pathophysiological implications of adenosine on intestinal motility disorders.
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Affiliation(s)
- Cátia Vieira
- Laboratório de Farmacologia e Neurobiologia/UMIB, Instituto de Ciências Biomédicas Abel Salazar-Universidade do Porto-ICBAS-UP, Portugal
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17
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Costa MA, Barbosa A, Neto E, Sá-e-Sousa A, Freitas R, Neves JM, Magalhães-Cardoso T, Ferreirinha F, Correia-de-Sá P. On the role of subtype selective adenosine receptor agonists during proliferation and osteogenic differentiation of human primary bone marrow stromal cells. J Cell Physiol 2011; 226:1353-66. [PMID: 20945394 DOI: 10.1002/jcp.22458] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purines are important modulators of bone cell biology. ATP is metabolized into adenosine by human primary osteoblast cells (HPOC); due to very low activity of adenosine deaminase, the nucleoside is the end product of the ecto-nucleotidase cascade. We, therefore, investigated the expression and function of adenosine receptor subtypes (A(1) , A(2A) , A(2B) , and A(3) ) during proliferation and osteogenic differentiation of HPOC. Adenosine A(1) (CPA), A(2A) (CGS21680C), A(2B) (NECA), and A(3) (2-Cl-IB-MECA) receptor agonists concentration-dependently increased HPOC proliferation. Agonist-induced HPOC proliferation was prevented by their selective antagonists, DPCPX, SCH442416, PSB603, and MRS1191. CPA and NECA facilitated osteogenic differentiation measured by increases in alkaline phosphatase (ALP) activity. This contrasts with the effect of CGS21680C which delayed HPOC differentiation; 2-Cl-IB-MECA was devoid of effect. Blockade of the A(2B) receptor with PSB603 prevented osteogenic differentiation by NECA. In the presence of the A(1) antagonist, DPCPX, CPA reduced ALP activity at 21 and 28 days in culture. At the same time points, blockade of A(2A) receptors with SCH442416 transformed the inhibitory effect of CGS21680C into facilitation. Inhibition of adenosine uptake with dipyridamole caused a net increase in osteogenic differentiation. The presence of all subtypes of adenosine receptors on HPOC was confirmed by immunocytochemistry. Data show that adenosine is an important regulator of osteogenic cell differentiation through the activation of subtype-specific receptors. The most abundant A(2B) receptor seems to have a consistent role in cell differentiation, which may be balanced through the relative strengths of A(1) or A(2A) receptors determining whether osteoblasts are driven into proliferation or differentiation.
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Affiliation(s)
- M Adelina Costa
- Laboratório de Farmacologia e Neurobiologia, UMIB, Instituto de Ciências Biomédicas Abel Salazar - Universidade do Porto (ICBAS-UP), Portugal
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Lavoie EG, Gulbransen BD, Martín-Satué M, Aliagas E, Sharkey KA, Sévigny J. Ectonucleotidases in the digestive system: focus on NTPDase3 localization. Am J Physiol Gastrointest Liver Physiol 2011; 300:G608-20. [PMID: 21233276 DOI: 10.1152/ajpgi.00207.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Extracellular nucleotides and adenosine are biologically active molecules that bind members of the P2 and P1 receptor families, respectively. In the digestive system, these receptors modulate various functions, including salivary, gastric, and intestinal epithelial secretion and enteric neurotransmission. The availability of P1 and P2 ligands is modulated by ectonucleotidases, enzymes that hydrolyze extracellular nucleotides into nucleosides. Nucleoside triphosphate diphosphohydrolases (NTPDases) and ecto-5'-nucleotidase are the dominant ectonucleotidases at physiological pH. While there is some information about the localization of ecto-5'-nucleotidase and NTPDase1 and -2, the distribution of NTPDase3 in the digestive system is unknown. We examined the localization of these ectonucleotidases, with a focus on NTPDase3, in the gastrointestinal tract and salivary glands. NTPDase1, -2, and -3 are responsible for ecto-ATPase activity in these tissues. Semiquantitative RT-PCR, immunohistochemistry, and in situ enzyme activity revealed the presence of NTPDase3 in some epithelial cells in serous acini of salivary glands and mucous acini and duct cells of sublingual salivary glands, in cells from the stratified esophageal and forestomach epithelia, and in some enteroendocrine cells of the gastric antrum. Interestingly, NTPDase2 and ecto-5'-nucleotidase are coexpressed with NTPDase3 in salivary gland cells and stratified epithelia. In the colon, neurons express NTPDase3 and glial cells express NTPDase2. Ca(2+) imaging experiments demonstrate that NTPDases regulate P2 receptor ligand availability in the enteric nervous system. In summary, the specific localization of NTPDase3 in the digestive system suggests functional roles of the enzyme, in association with NTPDase2 and ecto-5'-nucleotidase, in epithelial functions such as secretion and in enteric neurotransmission.
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Affiliation(s)
- Elise G Lavoie
- Centre de Recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec, QC, Canada
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19
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Antonioli L, Fornai M, Colucci R, Ghisu N, Tuccori M, Awwad O, Bin A, Zoppellaro C, Castagliuolo I, Gaion RM, Giron MC, Blandizzi C. Control of enteric neuromuscular functions by purinergic A(3) receptors in normal rat distal colon and experimental bowel inflammation. Br J Pharmacol 2010; 161:856-71. [PMID: 20860664 DOI: 10.1111/j.1476-5381.2010.00917.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Adenosine A(3) receptors mediate beneficial effects in experimental colitis, but their involvement in enteric neuromuscular functions during bowel inflammation is undetermined. This study investigated the regulatory role of A(3) receptors on colonic motility in the presence of experimental colitis. EXPERIMENTAL APPROACH Colitis was induced in rats by 2,4-dinitrobenzenesulfonic acid. A(3) receptors and adenosine deaminase (ADA, adenosine catabolic enzyme) mRNA were examined by RT-PCR. Tissue distribution of A(3) receptors was detected by confocal immunofluorescence. The effects of 2,3-ethyl-4,5-dipropyl-6-phenylpyridine-3-thiocarboxylate-5-carboxylate (MRS1523) (MRS, A(3) receptor antagonist), 2-chloro-N(6) -(3-iodobenzyl)-adenosine-5'-N-methyluronamide (2Cl-IB-MECA) (CIB, A(3) receptor agonist), dipyridamole (DIP, adenosine transport inhibitor) and ADA were assayed on contractile responses evoked by electrical stimulation (ES) or carbachol in colonic longitudinal muscle preparations (LMP). KEY RESULTS RT-PCR showed A(3) receptors and ADA mRNA in normal colon and their increased level in inflamed tissues. Immunofluorescence showed a predominant distribution of A(3) receptors in normal myenteric ganglia and an increased density during colitis. MRS enhanced ES-induced cholinergic contractions in normal LMP, but was less effective in inflamed tissues. After pretreatment with dipyridamole plus ADA, to reduce extracellular adenosine, CIB decreased cholinergic motor responses of normal LMP to ES, with enhanced efficacy in inflamed LMP. A(3) receptor ligands did not affect carbachol-induced contractions in LMP from normal or inflamed colon. CONCLUSIONS AND IMPLICATIONS Normally, adenosine modulated colonic cholinergic motility via activation of A(3) receptors in the myenteric plexus. A(3) receptor-mediated tonic inhibitory control by adenosine was impaired in inflamed bowel, despite increased density of functioning and pharmacologically recruitable A(3) receptors.
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Affiliation(s)
- L Antonioli
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa, Pisa, Italy
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20
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Zhang Y, Wang Y, Sun W, Jia L, Ma S, Gao Y. Strategy for studying the liver secretome on the organ level. J Proteome Res 2010; 9:1894-901. [PMID: 20148517 DOI: 10.1021/pr901057k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Secretome study presents new possibilities for understanding liver secretory function in a comprehensive and exploratory way. Perfusates from isolated perfused rat liver are good targets for liver secretome study on the organ level. There are two major concerns in this type of study, cytosolic and blood contaminations in the perfusates. Therefore, the perfusion conditions were carefully controlled and alanine aminotransferase levels in the perfusates were monitored as indicators of liver integrity and cytosolic contamination. The protein pattern of perfusate was significantly different from cell lysate, which showed low cytosolic contamination. The amount of immunoglobulins in the perfusates identified by both Western blot and MS/MS indicated low serum contamination. In total, 357 secretory protein candidates were identified by the Enrichment Index method or N-terminal signal peptide prediction. Secretory proteins annotated by Swiss-Prot were 5-fold enriched in the perfusates and around 10-fold enriched in the portion identified by the Enrichment Index method. Some cytokines, secretory proteins from liver interstitial cells, and components of the liver microenvironment were found in the perfusates, highlighting the advantages of studying the liver secretome on the organ level. The strategy can be used in physiology research and biomarker discovery for diseases in the liver as well as other organs.
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Affiliation(s)
- Yang Zhang
- National Key Laboratory of Medical Molecular Biology, Department of Physiology and Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences/School of Basic Medicine, Peking Union Medical College, Beijing, China
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21
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Nilsson KF, Grishina VA, Glaumann C, Gustafsson LE. Estimation of endogenous adenosine activity at adenosine receptors in guinea-pig ileum using a new pharmacological method. Acta Physiol (Oxf) 2010; 199:231-41. [PMID: 20121712 DOI: 10.1111/j.1748-1716.2010.02090.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Adenosine modulates neurotransmission and in the intestine adenosine is continuously released both from nerves and from smooth muscle. The main effect is modulation of contractile activity by inhibition of neurotransmitter release and by direct smooth muscle relaxation. Estimation of adenosine concentration at the receptors is difficult due to metabolic inactivation. We hypothesized that endogenous adenosine concentrations can be calculated by using adenosine receptor antagonist and agonist and dose ratio (DR) equations. METHODS Plexus-containing guinea-pig ileum longitudinal smooth muscle preparations were made to contract intermittently by electrical field stimulation in organ baths. Schild plot regressions were constructed with 2-chloroadenosine (agonist) and 8-(p-sulfophenyl)theophylline (8-PST; antagonist). In separate experiments the reversing or enhancing effect of 8-PST and the inhibiting effect of 2-chloroadenosine (CADO) were analysed in the absence or presence of an adenosine uptake inhibitor (dilazep), and nucleoside overflow was measured by HPLC. RESULTS Using the obtained DR, baseline adenosine concentration was calculated to 28 nm expressed as CADO activity, which increased dose dependently after addition of 10(-6) m dilazep to 150 nm (P < 0.05). HPLC measurements yielded a lower fractional increment (80%) in adenosine during dilazep, than found in the pharmacological determination (440%). CONCLUSION Endogenous adenosine is an important modulator of intestinal neuro-effector activity, operating in the linear part of the dose-response curve. Other adenosine-like agonists might contribute to neuromodulation and the derived formulas can be used to calculate endogenous agonist activity, which is markedly affected by nucleoside uptake inhibition. The method described should be suitable for other endogenous signalling molecules in many biological systems.
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Affiliation(s)
- K F Nilsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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22
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Vieira C, Duarte-Araújo M, Adães S, Magalhães-Cardoso T, Correia-de-Sá P. Muscarinic M(3) facilitation of acetylcholine release from rat myenteric neurons depends on adenosine outflow leading to activation of excitatory A(2A) receptors. Neurogastroenterol Motil 2009; 21:1118-e95. [PMID: 19470085 DOI: 10.1111/j.1365-2982.2009.01326.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Acetylcholine (ACh) is a major excitatory neurotransmitter in the myenteric plexus, and it regulates its own release acting via muscarinic autoreceptors. Adenosine released from stimulated myenteric neurons modulates ACh release preferentially via facilitatory A(2A) receptors. In this study, we investigated how muscarinic and adenosine receptors interplay to regulate ACh from the longitudinal muscle-myenteric plexus of the rat ileum. Blockade of the muscarinic M(2) receptor with 11-[[2-1[(diethylamino) methyl-1-piperidinyl]- acetyl]]-5,11-dihydro-6H-pyrido [2,3-b][1,4] benzodiazepine-6-one (AF-DX 116), 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) and atropine facilitated [3H]ACh release evoked by short stimulation trains (5 Hz, 200 pulses). Prolonging stimulus train length (>750 pulses) shifted muscarinic autoinhibition towards facilitatory M(3) receptors activation, as predicted by blockade with J104129 (a selective M(3) antagonist), 4-DAMP and atropine, whereas the selective M(2) antagonist, AF-DX 116, was without of effect. Blockade of A(2A) receptors with ZM 241385, inhibition of adenosine transport with dipyridamole, and inhibition of ecto-5'-nucleotidase with concanavalin A, all attenuated release inhibition caused by 4-DAMP. J104129 and 4-DAMP, but not AF-DX 116, decreased ( approximately 60%) evoked adenosine outflow (5 Hz, 3000 pulses). Oxotremorine (300 micromol L(-1)) facilitated the release of [3H]ACh (34 +/- 4%, n = 5) and adenosine (57 +/- 3%, n = 6) from stimulated myenteric neurons. 4-DAMP, dipyridamole and concanavalin A prevented oxotremorine-induced facilitation. ZM 241385 blocked oxotremorine facilitation of [3H]ACh release, but kept adenosine outflow unchanged. Thus, ACh modulates its own release from myenteric neurons by activating inhibitory M(2) and facilitatory M(3) autoreceptors. While the M(2) inhibition is prevalent during brief stimulation periods, muscarinic M(3) facilitation is highlighted during sustained nerve activity as it depends on extracellular adenosine accumulation leading to activation of facilitatory A(2A) receptors.
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Affiliation(s)
- C Vieira
- Laboratório de Farmacologia e Neurobiologia/UMIB, Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
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Oliveira L, Timóteo MA, Correia-de-Sá P. Negative crosstalk between M1 and M2 muscarinic autoreceptors involves endogenous adenosine activating A1 receptors at the rat motor endplate. Neurosci Lett 2009; 459:127-31. [DOI: 10.1016/j.neulet.2009.05.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 05/01/2009] [Accepted: 05/04/2009] [Indexed: 11/29/2022]
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Fornai M, Antonioli L, Colucci R, Ghisu N, Buccianti P, Marioni A, Chiarugi M, Tuccori M, Blandizzi C, Del Tacca M. A1 and A2a receptors mediate inhibitory effects of adenosine on the motor activity of human colon. Neurogastroenterol Motil 2009; 21:451-66. [PMID: 19019012 DOI: 10.1111/j.1365-2982.2008.01213.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Experimental evidence in animal models suggests that adenosine is involved in the regulation of digestive functions. This study examines the influence of adenosine on the contractile activity of human colon. Reverse transcription-polymerase chain reaction revealed A(1) and A(2a) receptor expression in colonic neuromuscular layers. Circular muscle preparations were connected to isotonic transducers to determine the effects of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; A(1) receptor antagonist), ZM 241385 (A(2a) receptor antagonist), CCPA (A(1) receptor agonist) and 2-[(p-2-carboxyethyl)-phenethylamino]-5'-N-ethyl-carboxamide-adenosine (CGS 21680; A(2a) receptor agonist) on motor responses evoked by electrical stimulation or carbachol. Electrically evoked contractions were enhanced by DPCPX and ZM 241385, and reduced by CCPA and CGS 21680. Similar effects were observed when colonic preparations were incubated with guanethidine (noradrenergic blocker), L-732,138, GR-159897 and SB-218795 (NK receptor antagonists). However, in the presence of guanethidine, NK receptor antagonists and N(omega)-propyl-L-arginine (NPA; neuronal nitric oxide synthase inhibitor), the effects of DPCPX and CCPA were still evident, while those of ZM 241385 and CGS 21680 no longer occurred. Carbachol-induced contractions were unaffected by A(2a) receptor ligands, but they were enhanced or reduced by DPCPX and CCPA, respectively. When colonic preparations were incubated with guanethidine, NK antagonists and atropine, electrically induced relaxations were partly reduced by ZM 241385 or NPA, but unaffected by DPCPX. Dipyridamole or application of exogenous adenosine reduced electrically and carbachol-evoked contractions, whereas adenosine deaminase enhanced such motor responses. In conclusion, adenosine exerts an inhibitory control on human colonic motility. A(1) receptors mediate direct modulating actions on smooth muscle, whereas A(2a) receptors operate through inhibitory nitrergic nerve pathways.
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Affiliation(s)
- M Fornai
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa, Pisa, Italy
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Duarte-Araújo M, Nascimento C, Timóteo MA, Magalhães-Cardoso MT, Correia-de-Sá P. Relative contribution of ecto-ATPase and ecto-ATPDase pathways to the biphasic effect of ATP on acetylcholine release from myenteric motoneurons. Br J Pharmacol 2009; 156:519-33. [PMID: 19154428 DOI: 10.1111/j.1476-5381.2008.00058.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The relative contribution of distinct ecto-nucleotidases to the modulation of purinergic signalling may depend on differential tissue distribution and substrate preference. EXPERIMENTAL APPROACH Extracellular ATP catabolism (assessed by high-performance liquid chromatography) and its influence on [(3)H]acetylcholine ([(3)H]ACh) release were investigated in the myenteric plexus of rat ileum in vitro. KEY RESULTS ATP was primarily metabolized via ecto-ATPDase (adenosine 5'-triphosphate diphosphohydrolase) into AMP, which was then dephosphorylated into adenosine by ecto-5'-nucleotidase. Alternative conversion of ATP into ADP by ecto-ATPase (adenosine 5'-triphosphatase) was more relevant at high ATP concentrations. ATP transiently increased basal [(3)H]ACh outflow in a 2',3'-O-(2,4,6-trinitrophenyl)adenosine-5'-triphosphate (TNP-ATP)-dependent, tetrodotoxin-independent manner. ATP and ATPgammaS (adenosine 5'-[gamma-thio]triphosphate), but not alpha,beta-methyleneATP, decreased [(3)H]ACh release induced by electrical stimulation. ADP and ADPbetaS (adenosine 5'[beta-thio]diphosphate) only decreased evoked [(3)H]ACh release. Inhibition by ADPbetaS was prevented by MRS 2179 (2'-deoxy-N(6)-methyl adenosine 3',5'-diphosphate diammonium salt, a selective P2Y(1) antagonist); blockade of ADP inhibition required co-application of MRS 2179 plus adenosine deaminase (which inactivates endogenous adenosine). Blockade of adenosine A(1) receptors with 1,3-dipropyl-8-cyclopentyl xanthine enhanced ADPbetaS inhibition, indicating that P2Y(1) stimulation is cut short by tonic adenosine A(1) receptor activation. MRS 2179 facilitated evoked [(3)H]ACh release, an effect reversed by the ecto-ATPase inhibitor, ARL67156, which delayed ATP conversion into ADP without affecting adenosine levels. CONCLUSIONS AND IMPLICATIONS ATP transiently facilitated [(3)H]ACh release from non-stimulated nerve terminals via prejunctional P2X (probably P2X(2)) receptors. Hydrolysis of ATP directly into AMP by ecto-ATPDase and subsequent formation of adenosine by ecto-5'-nucleotidase reduced [(3)H]ACh release via inhibitory adenosine A(1) receptors. Stimulation of inhibitory P2Y(1) receptors by ADP generated alternatively via ecto-ATPase might be relevant in restraining ACh exocytosis when ATP saturates ecto-ATPDase activity.
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Affiliation(s)
- M Duarte-Araújo
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal
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Ren J, Bertrand PP. Purinergic receptors and synaptic transmission in enteric neurons. Purinergic Signal 2008; 4:255-66. [PMID: 18368519 PMCID: PMC2486344 DOI: 10.1007/s11302-007-9088-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 11/06/2007] [Indexed: 12/16/2022] Open
Abstract
Purines such as ATP and adenosine participate in synaptic transmission in the enteric nervous system as neurotransmitters or neuromodulators. Purinergic receptors are localized on the cell bodies or nerve terminals of different functional classes of enteric neurons and, with other receptors, form unique receptor complements. Activation of purinergic receptors can regulate neuronal activity by depolarization, by regulating intracellular calcium, or by modulating second messenger pathways. Purinergic signaling between enteric neurons plays an important role in regulating specific enteric reflexes and overall gastrointestinal function. In the present article, we review evidence for purine receptors in the enteric nervous system, including P1 (adenosine) receptors and P2 (ATP) receptors. We will explore the role they play in mediating fast and slow synaptic transmission and in presynaptic inhibition of transmission. Finally, we will examine the molecular properties of the native receptors, their signaling mechanisms, and their role in gastrointestinal pathology.
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Affiliation(s)
- Jianhua Ren
- Neuroscience Program, Michigan State University, East Lansing, MI 48824 USA
| | - Paul P. Bertrand
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557 USA
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052 Australia
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Giron MC, Bin A, Brun P, Etteri S, Bolego C, Florio C, Gaion RM. Cyclic AMP in rat ileum: evidence for the presence of an extracellular cyclic AMP-adenosine pathway. Gastroenterology 2008; 134:1116-26. [PMID: 18316082 DOI: 10.1053/j.gastro.2008.01.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 01/04/2008] [Indexed: 01/30/2023]
Abstract
BACKGROUND & AIMS Extracellular adenosine plays a relevant role in regulating intestinal motility and preventing inflammatory processes. Adenosine 3',5'-cyclic monophosphate (cAMP) extruded from cells may be converted to adenosine monophosphate and then to adenosine by ecto-phosphodiesterase and CD73/ecto-5'nucleotidase, respectively, thus representing a source of adenosine. Our purpose was to assess the existence of a functional extracellular cAMP-adenosine pathway in intestinal tissue, obtaining evidence for CD73 expression and evaluating the effect of cAMP on ileum motility. METHODS The formation of cAMP metabolites in rat ileum strips incubated with exogenous cAMP or [(3)H]cAMP was monitored by high-performance liquid chromatography. CD73 was detected by immunoprecipitation and immunofluorescence. The functional activity of exogenous cAMP on ileum strips was recorded by measuring tension changes. RESULTS In ileum strips, the generation of cAMP-derived adenosine monophosphate, adenosine, and inosine was time and concentration dependent and was blocked by phosphodiesterase or CD73 inhibitors in a manner consistent with exogenous cAMP being processed through the extracellular cAMP-adenosine pathway. Accordingly, [(3)H]cAMP uptake in ileum strips was negligible. Immunofluorescence revealed CD73 surface expression on intestinal smooth muscle cells and intact smooth muscle. Exogenous cAMP concentration-dependently increased ileum muscle tension partially inhibited by adenosine inactivation or receptor blockade. Forskolin-stimulated endogenous cAMP induced concentration-dependent ileum relaxations. CONCLUSIONS A functioning extracellular cAMP-adenosine pathway featuring CD73 expression is present in rat ileum and affects intestinal motility. Extracellular cAMP may therefore act on intestinal muscle both directly by binding to specific smooth muscle cell membrane sites and indirectly through its degradation products.
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Affiliation(s)
- Maria Cecilia Giron
- Department of Pharmacology and Anesthesiology, University of Padova, Padova, Italy.
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Abstract
Adenine-based purines, such as adenosine and ATP, are ubiquitous molecules that, in addition to their roles in metabolism, act as modulators of neurotransmitter release through activation of presynaptic P1 purinoceptors or adenosine receptors (activated by adenosine) and P2 receptors (activated by nucleotides). Of the latter, the P2Y receptors are G protein-coupled, whereas the P2X receptors are ligand-gated ion channels and not covered in this review.
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MESH Headings
- Adenosine/pharmacology
- Adenosine/physiology
- Animals
- Humans
- Neurotransmitter Agents/metabolism
- Purines/metabolism
- Receptor, Adenosine A1/drug effects
- Receptor, Adenosine A1/metabolism
- Receptors, Adenosine A2/drug effects
- Receptors, Adenosine A2/metabolism
- Receptors, Presynaptic/drug effects
- Receptors, Presynaptic/physiology
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/physiology
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/physiology
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Affiliation(s)
- Jorge Gonçalves
- Department of Pharmacology, University of Porto, Porto, Portugal.
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Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
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