1
|
Alveal M, Méndez A, García A, Henríquez M. Purinergic regulation of pulmonary vascular tone. Purinergic Signal 2024; 20:595-606. [PMID: 38713328 PMCID: PMC11554604 DOI: 10.1007/s11302-024-10010-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 04/16/2024] [Indexed: 05/08/2024] Open
Abstract
Purinergic signaling is a crucial determinant in the regulation of pulmonary vascular physiology and presents a promising avenue for addressing lung diseases. This intricate signaling system encompasses two primary receptor classes: P1 and P2 receptors. P1 receptors selectively bind adenosine, while P2 receptors exhibit an affinity for ATP, ADP, UTP, and UDP. Functionally, P1 receptors are associated with vasodilation, while P2 receptors mediate vasoconstriction, particularly in basally relaxed vessels, through modulation of intracellular Ca2+ levels. The P2X subtype receptors facilitate extracellular Ca2+ influx, while the P2Y subtype receptors are linked to endoplasmic reticulum Ca2+ release. Notably, the primary receptor responsible for ATP-induced vasoconstriction is P2X1, with α,β-meATP and UDP being identified as potent vasoconstrictor agonists. Interestingly, ATP has been shown to induce endothelium-dependent vasodilation in pre-constricted vessels, associated with nitric oxide (NO) release. In the context of P1 receptors, adenosine stimulation of pulmonary vessels has been unequivocally demonstrated to induce vasodilation, with a clear dependency on the A2B receptor, as evidenced in studies involving guinea pigs and rats. Importantly, evidence strongly suggests that this vasodilation occurs independently of endothelium-mediated mechanisms. Furthermore, studies have revealed variations in the expression of purinergic receptors across different vessel sizes, with reports indicating notably higher expression of P2Y1, P2Y2, and P2Y4 receptors in small pulmonary arteries. While the existing evidence in this area is still emerging, it underscores the urgent need for a comprehensive examination of the specific characteristics of purinergic signaling in the regulation of pulmonary vascular tone, particularly focusing on the disparities observed across different intrapulmonary vessel sizes. Consequently, this review aims to meticulously explore the current evidence regarding the role of purinergic signaling in pulmonary vascular tone regulation, with a specific emphasis on the variations observed in intrapulmonary vessel sizes. This endeavor is critical, as purinergic signaling holds substantial promise in the modulation of vascular tone and in the proactive prevention and treatment of pulmonary vascular diseases.
Collapse
Affiliation(s)
- Marco Alveal
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile
| | - Andrea Méndez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile
- Escuela de Kinesiología, Facultad de Salud y Ciencias Sociales, Campus Providencia, Sede Santiago, Universidad de Las Américas, Santiago, Chile
| | - Aline García
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile
- Escuela de Graduados, Facultad de Ciencias Veterinarias,, Universidad Austral de Chile, Valdivia, Chile
| | - Mauricio Henríquez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile.
| |
Collapse
|
2
|
Characterisation of P2Y receptor subtypes mediating vasodilation and vasoconstriction of rat pulmonary artery using selective antagonists. Purinergic Signal 2022; 18:515-528. [PMID: 36018534 PMCID: PMC9832182 DOI: 10.1007/s11302-022-09895-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/12/2022] [Indexed: 01/14/2023] Open
Abstract
Pulmonary vascular tone is modulated by nucleotides, but which P2 receptors mediate these actions is largely unclear. The aim of this study, therefore, was to use subtype-selective antagonists to determine the roles of individual P2Y receptor subtypes in nucleotide-evoked pulmonary vasodilation and vasoconstriction. Isometric tension was recorded from rat intrapulmonary artery rings (i.d. 200-500 µm) mounted on a wire myograph. Nucleotides evoked concentration- and endothelium-dependent vasodilation of precontracted tissues, but the concentration-response curves were shallow and did not reach a plateau. The selective P2Y2 antagonist, AR-C118925XX, inhibited uridine 5'-triphosphate (UTP)- but not adenosine 5'-triphosphate (ATP)-evoked relaxation, whereas the P2Y6 receptor antagonist, MRS2578, had no effect on UTP but inhibited relaxation elicited by uridine 5'-diphosphate (UDP). ATP-evoked relaxations were unaffected by the P2Y1 receptor antagonist, MRS2179, which substantially inhibited responses to adenosine 5'-diphosphate (ADP), and by the P2Y12/13 receptor antagonist, cangrelor, which potentiated responses to ADP. Both agonists were unaffected by CGS1593, an adenosine receptor antagonist. Finally, AR-C118925XX had no effect on vasoconstriction elicited by UTP or ATP at resting tone, although P2Y2 receptor mRNA was extracted from endothelium-denuded tissues using reverse transcription polymerase chain reaction with specific oligonucleotide primers. In conclusion, UTP elicits pulmonary vasodilation via P2Y2 receptors, whereas UDP acts at P2Y6 and ADP at P2Y1 receptors, respectively. How ATP induces vasodilation is unclear, but it does not involve P2Y1, P2Y2, P2Y12, P2Y13, or adenosine receptors. UTP- and ATP-evoked vasoconstriction was not mediated by P2Y2 receptors. Thus, this study advances our understanding of how nucleotides modulate pulmonary vascular tone.
Collapse
|
3
|
Matsumoto T, Takayanagi K, Katome T, Kojima M, Taguchi K, Kobayashi T. Extracellular Uridine Nucleotides-Induced Contractions Were Increased in Femoral Arteries of Spontaneously Hypertensive Rats. Pharmacology 2021; 106:435-445. [PMID: 34139711 DOI: 10.1159/000516893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/27/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Femoral arterial dysfunction including abnormal vascular responsiveness to endogenous ligands was often seen in arterial hypertension. Extracellular nucleotides including uridine 5'-diphosphate (UDP) and uridine 5'-triphosphate (UTP) play important roles for homeostasis in the vascular system including controlling the vascular tone. However, responsiveness to UDP and UTP in femoral arteries under arterial hypertension remains unclear. The aim of this study was to investigate if hypertension has an effect of vasoconstrictive responsiveness to UDP and UTP in femoral arteries of spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats (WKYs) after 7 and 12 months old. METHODS Organ baths were conducted to determine vascular reactivity in isolated femoral arterial rings. RESULTS In femoral arteries obtained from 12-month-old rats, augmented contractile responses to UDP and UTP were seen in femoral arteries of SHR than in those of WKY under situations not only intact but also nitric oxide synthase inhibition, whereas no difference of extracellular potassium-induced vasocontraction was seen in both SHR and WKY groups. Similar contraction trends occurred in femoral arteries obtained from 7-month-old rats. Moreover, contractions induced by UDP and UTP were increased in endothelium-denuded arteries. Cyclooxygenase inhibition decreased the contractions induced by these nucleotides and abolished the differences in responses between the SHR and WKY groups. CONCLUSIONS This study demonstrates the importance of regulation of extracellular uridine nucleotides-induced contractions in hypertension-associated peripheral arterial diseases.
Collapse
Affiliation(s)
- Takayuki Matsumoto
- Institute of Medicinal Chemistry, Department of Physiology and Morphology, Hoshi University, Tokyo, Japan
| | - Keisuke Takayanagi
- Institute of Medicinal Chemistry, Department of Physiology and Morphology, Hoshi University, Tokyo, Japan
| | - Tomoki Katome
- Institute of Medicinal Chemistry, Department of Physiology and Morphology, Hoshi University, Tokyo, Japan
| | - Mihoka Kojima
- Institute of Medicinal Chemistry, Department of Physiology and Morphology, Hoshi University, Tokyo, Japan
| | - Kumiko Taguchi
- Institute of Medicinal Chemistry, Department of Physiology and Morphology, Hoshi University, Tokyo, Japan
| | - Tsuneo Kobayashi
- Institute of Medicinal Chemistry, Department of Physiology and Morphology, Hoshi University, Tokyo, Japan
| |
Collapse
|
4
|
Matsumoto T, Takayanagi K, Kojima M, Taguchi K, Kobayashi T. Differential Contractile Reactivity to Nucleotides in Femoral Arteries of OLETF and LETO Rats. Biol Pharm Bull 2020; 43:1987-1992. [PMID: 33268721 DOI: 10.1248/bpb.b20-00653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Extracellular nucleotides play an important role in the regulation of vascular function, and an abnormal vascular function is an important participant in the development and progression of diabetic vascular complications. The purpose of this study was to determine whether contractile responses induced by extracellular nucleotides and a dinucleotide, uridine adenosine tetraphosphate (Up4A), in femoral arteries would be altered at the chronic stage of type 2 diabetes. We determined the changes in contractile reactivity induced by ATP, uridine triphosphate (UTP), uridine diphosphate (UDP), and Up4A in the femoral arteries of Otsuka Long-Evans Tokushima Fatty (OLETF) rats (aged male type 2 diabetic rats) and, Long-Evans Tokushima Otsuka (LETO) rats (controls for OLETF rats). ATP-induced contractions were greater in OLETF rats than in LETO rats. UTP-induced contractions were lower in OLETF rats than in LETO rats. UDP- and Up4A-induced contractions were similar between OLETF and LETO rats. The femoral artery contractile changes induced by the extracellular nucleotides and dinucleotide were similar when nitric oxide synthase was inhibited. These results suggest that the extent of femoral artery contractile reactivity to nucleotides/dinucleotides differs during long-term duration of type 2 diabetes.
Collapse
Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University
| | - Keisuke Takayanagi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University
| | - Mihoka Kojima
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University
| | - Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University
| |
Collapse
|
5
|
Amplification of the COX/TXS/TP receptor pathway enhances uridine diphosphate-induced contraction by advanced glycation end products in rat carotid arteries. Pflugers Arch 2019; 471:1505-1517. [PMID: 31736003 DOI: 10.1007/s00424-019-02330-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 12/18/2022]
Abstract
Advanced glycation end products (AGEs) play a pivotal role in vascular functions under various pathophysiological conditions. Although uridine diphosphate (UDP) is an important extracellular nucleotide, the relationship between AGEs and UDP regarding their effect on vascular functions remains unclear. Therefore, we investigated the effects of AGE-bovine serum albumin (AGE-BSA) on UDP-mediated responses in rat thoracic aorta and carotid arteries. In rat thoracic aorta, UDP-induced relaxation was observed and this relaxation was similar between control (1.0 v/v% PBS) and AGE-BSA-treated (0.1 mg/mL for 60 min) groups. In contrast, contraction but not relaxation was obtained following UDP application to carotid arteries with and without endothelia; contraction was greater in the AGE-BSA-treated group than in the control group. The difference in UDP-induced contraction between the two groups was not abolished by the use of a nitric oxide synthase (NOS) inhibitor, whereas it was abolished by the use of cyclooxygenase (COX), thromboxane synthase (TXS), and thromboxane-prostanoid (TP) receptor antagonist. Further, the difference in UDP-induced contraction was not abolished by the use of a cPLA2 inhibitor, whereas it was abolished by the use of an iPLA2 inhibitor. UDP increased TXA2 release in both groups, and its level was similar in both groups. Moreover, the release of PGE2, PGF2α, and PGI2 was similar among the groups. Under NOS inhibition, TP receptor agonist-induced contraction increased in the AGE-BSA-treated group (vs. control group). In conclusion, the increase in UDP-induced carotid arterial contraction by AGE-BSA can be attributed to an increase in the COX/TXS/TP receptor pathway, particularly, TP receptor signaling.
Collapse
|
6
|
Kylhammar D, Rådegran G. The principal pathways involved in the in vivo modulation of hypoxic pulmonary vasoconstriction, pulmonary arterial remodelling and pulmonary hypertension. Acta Physiol (Oxf) 2017; 219:728-756. [PMID: 27381367 DOI: 10.1111/apha.12749] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 06/10/2016] [Accepted: 07/04/2016] [Indexed: 12/13/2022]
Abstract
Hypoxic pulmonary vasoconstriction (HPV) serves to optimize ventilation-perfusion matching in focal hypoxia and thereby enhances pulmonary gas exchange. During global hypoxia, however, HPV induces general pulmonary vasoconstriction, which may lead to pulmonary hypertension (PH), impaired exercise capacity, right-heart failure and pulmonary oedema at high altitude. In chronic hypoxia, generalized HPV together with hypoxic pulmonary arterial remodelling, contribute to the development of PH. The present article reviews the principal pathways in the in vivo modulation of HPV, hypoxic pulmonary arterial remodelling and PH with primary focus on the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways. In summary, endothelin-1 and thromboxane A2 may enhance, whereas nitric oxide and prostacyclin may moderate, HPV as well as hypoxic pulmonary arterial remodelling and PH. The production of prostacyclin seems to be coupled primarily to cyclooxygenase-1 in acute hypoxia, but to cyclooxygenase-2 in chronic hypoxia. The potential role of adenine nucleotides in modulating HPV is unclear, but warrants further study. Additional modulators of the pulmonary vascular responses to hypoxia may include angiotensin II, histamine, serotonin/5-hydroxytryptamine, leukotrienes and epoxyeicosatrienoic acids. Drugs targeting these pathways may reduce acute and/or chronic hypoxic PH. Endothelin receptor antagonists and phosphodiesterase-5 inhibitors may additionally improve exercise capacity in hypoxia. Importantly, the modulation of the pulmonary vascular responses to hypoxia varies between species and individuals, with hypoxic duration and age. The review also define how drugs targeting the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways may improve pulmonary haemodynamics, but also impair pulmonary gas exchange by interference with HPV in chronic lung diseases.
Collapse
Affiliation(s)
- D. Kylhammar
- Department of Clinical Sciences Lund, Cardiology; Faculty of Medicine; Lund University; Lund Sweden
- The Section for Heart Failure and Valvular Disease; VO Heart and Lung Medicine; Skåne University Hospital; Lund Sweden
| | - G. Rådegran
- Department of Clinical Sciences Lund, Cardiology; Faculty of Medicine; Lund University; Lund Sweden
- The Section for Heart Failure and Valvular Disease; VO Heart and Lung Medicine; Skåne University Hospital; Lund Sweden
| |
Collapse
|
7
|
Dai ZK, Kao CL, Hsieh SL, Chen IJ, Wu BN. Restoration of uridine 5'-triphosphate-suppressed delayed rectifying K + currents by an NO activator KMUP-1 involves RhoA/Rho kinase signaling in pulmonary artery smooth muscle cells. Kaohsiung J Med Sci 2016; 32:607-613. [PMID: 27914611 DOI: 10.1016/j.kjms.2016.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/19/2016] [Accepted: 09/29/2016] [Indexed: 12/01/2022] Open
Abstract
We have demonstrated that KMUP-1 (7-[2-[4-(2-chlorobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine) blunts monocrotaline-induced pulmonary arterial hypertension by altering Ca2+ sensitivity, K+-channel function, endothelial nitric oxide synthase activity, and RhoA/Rho kinase (ROCK) expression. This study further investigated whether KMUP-1 impedes uridine 5'-triphosphate (UTP)-inhibited delayed rectifying K+ (KDR) current in rat pulmonary arteries involved the RhoA/ROCK signaling. Pulmonary artery smooth muscle cells (PASMCs) were enzymatically dissociated from rat pulmonary arteries. KMUP-1 (30μM) attenuated UTP (30μM)-mediated membrane depolarization and abolished UTP-enhanced cytosolic Ca2+ concentration. Whole-cell patch-clamp electrophysiology was used to monitor KDR currents. A voltage-dependent KDR current was isolated and shown to consist of a 4-aminopyridine (5mM)-sensitive component and an insensitive component. The 4-aminopyridine sensitive KDR current was suppressed by UTP (30μM). The ROCK inhibitor Y27632 (30μM) abolished the ability of UTP to inhibit the KDR current. Like Y27632, KMUP-1 (30μM) similarly abolished UTP-inhibited KDR currents. Superfused protein kinase A and protein kinase G inhibitors (KT5720, 300nM and KT5823, 300nM) did not affect UTP-inhibited KDR currents, but the currents were restored by adding KMUP-1 (30μM) to the superfusate. KMUP-1 reversal of KDR current inhibition by UTP predominantly involves the ROCK inhibition. The results indicate that the RhoA/ROCK signaling pathway plays a key role in eliciting PASMCs depolarization caused by UTP, which would result in pulmonary artery constriction. KMUP-1 blocks UTP-mediated PASMCs depolarization, suggesting that it would prevent abnormal pulmonary vasoconstriction.
Collapse
Affiliation(s)
- Zen-Kong Dai
- Department of Pediatrics, Division of Pediatric Pulmonology and Cardiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chang-Ling Kao
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Su-Ling Hsieh
- Department of Pharmacy, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Ing-Jun Chen
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Bin-Nan Wu
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan.
| |
Collapse
|
8
|
Dominguez Rieg JA, Burt JM, Ruth P, Rieg T. P2Y₂ receptor activation decreases blood pressure via intermediate conductance potassium channels and connexin 37. Acta Physiol (Oxf) 2015; 213:628-41. [PMID: 25545736 PMCID: PMC4442688 DOI: 10.1111/apha.12446] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/14/2014] [Accepted: 12/17/2014] [Indexed: 02/06/2023]
Abstract
AIMS Nucleotides are important paracrine regulators of vascular tone. We previously demonstrated that activation of P2Y₂ receptors causes an acute, NO-independent decrease in blood pressure, indicating this signalling pathway requires an endothelial-derived hyperpolarization (EDH) response. To define the mechanisms by which activation of P2Y₂ receptors initiates EDH and vasodilation, we studied intermediate-conductance (KCa3.1, expressed in endothelial cells) and big-conductance potassium channels (KCa1.1, expressed in smooth muscle cells) as well as components of the myoendothelial gap junction, connexins 37 and 40 (Cx37, Cx40), all hypothesized to be part of the EDH response. METHODS We compared the effects of a P2Y₂/₄ receptor agonist in wild-type (WT) mice and in mice lacking KCa3.1, KCa1.1, Cx37 or Cx40 under anaesthesia, while monitoring intra-arterial blood pressure and heart rate. RESULTS Acute activation of P2Y₂/₄ receptors (0.01-3 mg kg(-1) body weight i.v.) caused a biphasic blood pressure response characterized by a dose-dependent and rapid decrease in blood pressure in WT (maximal response % of baseline at 3 mg kg(-1) : -38 ± 1%) followed by a consecutive increase in blood pressure (+44 ± 11%). The maximal responses in KCa3.1(-/-) and Cx37(-/-) were impaired (-13 ± 5, +17 ± 7 and -27 ± 1, +13 ± 3% respectively), whereas the maximal blood pressure decrease in response to acetylcholine at 3 μg kg(-1) was not significantly different (WT: -53 ± 3%; KCa3.1(-/-) : -52 ± 3; Cx37(-/-) : -53 ± 3%). KCa1.1(-/-) and Cx40(-/-) showed an identical biphasic response to P2Y2/4 receptor activation compared to WT. CONCLUSIONS The data suggest that the P2Y2/4 receptor activation elicits blood pressure responses via distinct mechanisms involving KCa3.1 and Cx37.
Collapse
MESH Headings
- Animals
- Blood Pressure/drug effects
- Connexins/deficiency
- Connexins/genetics
- Connexins/metabolism
- Dose-Response Relationship, Drug
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Heart Rate/drug effects
- Inosine/analogs & derivatives
- Inosine/pharmacology
- Intermediate-Conductance Calcium-Activated Potassium Channels/deficiency
- Intermediate-Conductance Calcium-Activated Potassium Channels/genetics
- Intermediate-Conductance Calcium-Activated Potassium Channels/metabolism
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism
- Male
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Nitric Oxide Synthase Type III/genetics
- Nitric Oxide Synthase Type III/metabolism
- Purinergic P2Y Receptor Agonists
- Receptors, Purinergic P2Y2/drug effects
- Receptors, Purinergic P2Y2/metabolism
- Signal Transduction/drug effects
- Uridine Triphosphate/analogs & derivatives
- Uridine Triphosphate/pharmacology
- Vasodilation/drug effects
- Gap Junction alpha-4 Protein
Collapse
Affiliation(s)
- J. A. Dominguez Rieg
- Department of Basic Sciences, Bastyr University California, San Diego, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
| | - J. M. Burt
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - P. Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Tübingen, Germany
| | - T. Rieg
- VA San Diego Healthcare System, San Diego, CA, USA
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|
9
|
Burnstock G, Ralevic V. Purinergic signaling and blood vessels in health and disease. Pharmacol Rev 2013; 66:102-92. [PMID: 24335194 DOI: 10.1124/pr.113.008029] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK; and Department of Pharmacology, The University of Melbourne, Australia.
| | | |
Collapse
|
10
|
Mitchell C, Syed NIH, Tengah A, Gurney AM, Kennedy C. Identification of Contractile P2Y1, P2Y6, and P2Y12Receptors in Rat Intrapulmonary Artery Using Selective Ligands. J Pharmacol Exp Ther 2012; 343:755-62. [DOI: 10.1124/jpet.112.198051] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
|
11
|
Burnstock G, Brouns I, Adriaensen D, Timmermans JP. Purinergic signaling in the airways. Pharmacol Rev 2012; 64:834-68. [PMID: 22885703 DOI: 10.1124/pr.111.005389] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Evidence for a significant role and impact of purinergic signaling in normal and diseased airways is now beyond dispute. The present review intends to provide the current state of knowledge of the involvement of purinergic pathways in the upper and lower airways and lungs, thereby differentiating the involvement of different tissues, such as the epithelial lining, immune cells, airway smooth muscle, vasculature, peripheral and central innervation, and neuroendocrine system. In addition to the vast number of well illustrated functions for purinergic signaling in the healthy respiratory tract, increasing data pointing to enhanced levels of ATP and/or adenosine in airway secretions of patients with airway damage and respiratory diseases corroborates the emerging view that purines act as clinically important mediators resulting in either proinflammatory or protective responses. Purinergic signaling has been implicated in lung injury and in the pathogenesis of a wide range of respiratory disorders and diseases, including asthma, chronic obstructive pulmonary disease, inflammation, cystic fibrosis, lung cancer, and pulmonary hypertension. These ostensibly enigmatic actions are based on widely different mechanisms, which are influenced by the cellular microenvironment, but especially the subtypes of purine receptors involved and the activity of distinct members of the ectonucleotidase family, the latter being potential protein targets for therapeutic implementation.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Royal Free Campus, London, UK.
| | | | | | | |
Collapse
|
12
|
Mitchell C, Syed NIH, Gurney AM, Kennedy C. A Ca²⁺-dependent chloride current and Ca²⁺ influx via Ca(v)1.2 ion channels play major roles in P2Y receptor-mediated pulmonary vasoconstriction. Br J Pharmacol 2012; 166:1503-12. [PMID: 22320222 PMCID: PMC3417463 DOI: 10.1111/j.1476-5381.2012.01892.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 12/19/2011] [Accepted: 01/31/2012] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND AND PURPOSE ATP, UTP and UDP act at smooth muscle P2X and P2Y receptors to constrict rat intrapulmonary arteries, but the underlying signalling pathways are poorly understood. Here, we determined the roles of the Ca²⁺ -dependent chloride ion current (I(Cl,Ca)), Ca(v)1.2 ion channels and Ca²⁺ influx. EXPERIMENTAL APPROACH Isometric tension was recorded from endothelium-denuded rat intrapulmonary artery rings (i.d. 200-500 µm) mounted on a wire myograph. KEY RESULTS The I(Cl,Ca) blockers, niflumic acid and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid and the Ca(v)1.2 channel blocker, nifedipine, reduced peak amplitude of contractions evoked by UTP and UDP by ∼45-50% and in a non-additive manner. Ca²⁺-free buffer inhibited responses by ∼70%. Niflumic acid and nifedipine similarly depressed contractions to ATP, but Ca²⁺-free buffer almost abolished the response. After peaking, contractions to UTP and UDP decayed slowly by 50-70% to a sustained plateau, which was rapidly inhibited by niflumic acid and nifedipine. Contractions to ATP, however, reversed rapidly and fully. Tannic acid contracted tissues per se and potentiated nucleotide-evoked contractions. CONCLUSIONS AND IMPLICATIONS I (Cl,Ca) and Ca²⁺ influx via Ca(v)1.2 ion channels contribute substantially and equally to contractions of rat intrapulmonary arteries evoked by UTP and UDP, via P2Y receptors. ATP also activates these mechanisms via P2Y receptors, but the greater dependence on extracellular Ca²⁺ most likely reflects additional influx through the P2X1 receptor pore. The lack of a sustained response to ATP is probably due to it acting at P2 receptor subtypes that desensitize rapidly. Thus multiple signalling mechanisms contribute to pulmonary artery vasoconstriction mediated by P2 receptors.
Collapse
Affiliation(s)
- Callum Mitchell
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | | | | | | |
Collapse
|
13
|
Rieg T, Gerasimova M, Boyer JL, Insel PA, Vallon V. P2Y₂ receptor activation decreases blood pressure and increases renal Na⁺ excretion. Am J Physiol Regul Integr Comp Physiol 2011; 301:R510-8. [PMID: 21613580 DOI: 10.1152/ajpregu.00148.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ATP and UTP are endogenous agonists of P2Y(2/4) receptors. To define the in vivo effects of P2Y(2) receptor activation on blood pressure and urinary excretion, we compared the response to INS45973, a P2Y(2/4) receptor agonist and UTP analog, in wild-type (WT) and P2Y(2) receptor knockout (P2Y(2)-/-) mice. INS45973 was administered intravenously as a bolus injection or continuous infusion to determine effects on blood pressure and renal function, respectively. Within seconds, bolus application of INS45973 (0.1 to 3 mg/kg body wt) dose-dependently decreased blood pressure in WT (maximum response -35 ± 2 mmHg) and to a similar extent in endothelial nitric oxide synthase knockout mice. By contrast, blood pressure increased in P2Y(2)-/- (maximum response +18 ± 1 mmHg) but returned to basal levels within 60 s. Continuous infusion of INS45973 (25 to 750 μg·min(-1)·kg(-1) body wt) dose-dependently increased urinary excretion of Na(+) in WT (maximum response +46 ± 15%) but reduced Na(+) excretion in P2Y(2)-/- (maximum responses of -45 ± 15%) mice. In renal clearance experiments, INS45973 did not affect glomerular filtration rate but lowered blood pressure and increased fractional excretion of fluid, Na(+), and K(+) in WT relative to P2Y(2)-/- mice. The blood pressure responses to INS45973 are consistent with P2Y(2) receptor-mediated NO-independent vasodilation and implicate responses to endothelium-derived hyperpolarizing factor, and P2Y(2) receptor-independent vasoconstriction, probably via activation of P2Y(4) receptors on smooth muscle. Systemic activation of P2Y(2) receptors thus lowers blood pressure and inhibits renal Na(+) reabsorption, effects suggesting the potential utility of P2Y(2) agonism in the treatment of hypertension.
Collapse
Affiliation(s)
- Timo Rieg
- Department of Medicine, University of California San Diego, La Jolla, California 92161, USA.
| | | | | | | | | |
Collapse
|
14
|
Characterisation of P2X receptors expressed in rat pulmonary arteries. Eur J Pharmacol 2010; 649:342-8. [DOI: 10.1016/j.ejphar.2010.09.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 08/27/2010] [Accepted: 09/07/2010] [Indexed: 12/31/2022]
|
15
|
Bradley E, Kadima S, Drumm B, Hollywood MA, Thornbury KD, McHale NG, Sergeant GP. Novel excitatory effects of adenosine triphosphate on contractile and pacemaker activity in rabbit urethral smooth muscle. J Urol 2010; 183:801-11. [PMID: 20022059 DOI: 10.1016/j.juro.2009.09.075] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE Adenosine triphosphate is thought to be an important neurotransmitter in urethral smooth muscle but its physiological role is still unclear. We characterized the effects of adenosine triphosphate on contractile and pacemaker activity in rabbit urethral smooth muscle. MATERIALS AND METHODS Tension recordings were made from strips of rabbit proximal urethral smooth muscle. Membrane currents from freshly isolated smooth muscle cells and interstitial cells of Cajal were recorded using the patch clamp technique. Intracellular Ca(2+) was measured using confocal microscopy. RESULTS Exogenous application of adenosine triphosphate (10 microM) evoked robust contractions that were inhibited by the type 2 purinergic receptor blocker suramin (100 microM) and the selective type 2 purinergic Y1 receptor antagonist MRS2500 (Tocris Bioscience, Ellisville, Missouri) (100 nM). Application of the type 2 purinergic Y receptor agonist 2-MeSADP (1 microM) mimicked the effects of adenosine triphosphate. When smooth muscle cells were studied under voltage clamp at -60 mV, adenosine triphosphate evoked a large single inward current (greater than 1.2 nA) but 2-MeSADP produced a small current (about 16 pA). In contrast, when interstitial cells of Cajal were held at -60 mV, they showed spontaneous transient inward currents that were increased in frequency by adenosine triphosphate and 2-MeSADP. These excitatory effects were inhibited by suramin and MRS2500. Interstitial cells of Cajal showed spontaneous Ca(2+) waves that were increased in frequency by adenosine triphosphate and 2-MeSADP. These effects were also inhibited by suramin and MRS2500. CONCLUSIONS Contractile effects of adenosine triphosphate in urethral smooth muscle are mediated by the activation of type 2 purinergic Y receptors on interstitial cells of Cajal.
Collapse
Affiliation(s)
- Eamonn Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | | | | | | | | | | | | |
Collapse
|
16
|
Lau DHW, Metcalfe MJ, Mumtaz FH, Mikhailidis DP, Thompson CS. Purinergic modulation of human corpus cavernosum relaxation. ACTA ACUST UNITED AC 2009; 32:149-55. [DOI: 10.1111/j.1365-2605.2007.00828.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
17
|
Luminal ATP-induced contraction of rabbit pulmonary arteries and role of purinoceptors in the regulation of pulmonary arterial pressure. Pflugers Arch 2008; 457:281-91. [PMID: 18542991 DOI: 10.1007/s00424-008-0536-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/27/2008] [Accepted: 05/16/2008] [Indexed: 10/22/2022]
Abstract
The effects of luminal ATP between rabbit pulmonary (PAs) and coronary arteries (CAs) were compared to understand the role of purinoceptors in the regulation of pulmonary arterial pressure (PAP) under hypoxia. Diameters of vessels were video analyzed under luminal perfusion. ATP-induced membrane currents and intracellular Ca(2+) signals ([Ca(2+)](i)) were compared in pulmonary (PASMCs) and coronary myocytes (CASMCs) using patch clamp and spectrofluorimetry. PAP was measured in perfused lungs under ventilation. Luminal ATP induced constriction of rabbit PAs in the presence of endothelium. In contrast, CAs showed dilating responses to luminal ATP even in the absence of endothelium. In PASMCs, both P2X-mediated inward current and P2Y-mediated store Ca(2+) release were consistently observed. In contrast, CASMCs showed neither P2X nor P2Y responses. In the perfused lungs, hypoxia-induced PAP increase was decreased by suramin, a purinergic antagonist. A luminal application of alpha,beta-meATP largely increased PAP, whereas UTP decreased PAP. The combined application of P2X- and P2Y-selective agonists (alpha,beta-meATP and UTP) increased PAP. However, the perfusion of ATP alone decreased PAP, and the ATP-induced PAP decrease was affected neither by adenosine receptor antagonist nor by nitric oxide synthase inhibitor. In summary, although the luminal ATP constricts isolated PAs and suramin attenuated the HPV of perfused lungs, the bimodal responses of PAP to purinergic agonists indicate that the luminal ATP regulates pulmonary circulation via complex signaling interactions in situ.
Collapse
|
18
|
Bar I, Guns PJ, Metallo J, Cammarata D, Wilkin F, Boeynams JM, Bult H, Robaye B. Knockout mice reveal a role for P2Y6 receptor in macrophages, endothelial cells, and vascular smooth muscle cells. Mol Pharmacol 2008; 74:777-84. [PMID: 18523137 DOI: 10.1124/mol.108.046904] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
P2Y receptors are G-protein-coupled receptors activated by extracellular nucleotides. The P2Y(6) receptor is selectively activated by UDP, and its transcript has been detected in numerous organs, including the spleen, thymus, intestine, blood leukocytes, and aorta. To investigate the biological functions of this receptor, we generated P2Y(6)-null mice by gene targeting. The P2Y(6) knockout (KO) mice are viable and are not distinguishable from the wild-type (WT) mice in terms of growth or fertility. In thioglycollate-elicited macrophages, the production of inositol phosphate in response to UDP stimulation was lost, indicating that P2Y(6) is the unique UDP-responsive receptor expressed by mouse macrophages. Furthermore, the amount of interleukin-6 and macrophage-inflammatory protein-2, but not tumor necrosis factor-alpha, released in response to lipopolysaccharide stimulation was significantly enhanced in the presence of UDP, and this effect was lost in the P2Y(6) KO macrophages. The endothelium-dependent relaxation of the aorta by UDP was abolished in KO P2Y(6) mice. The contractile effect of UDP on the aorta, observed when endothelial nitric-oxide synthase is blocked, was also abolished in P2Y(6)-null mice. In conclusion, we generated P2Y(6)-deficient mice and have shown that these mice have a defective response to UDP in macrophages, endothelial cells, and vascular smooth muscle cells. These observations might be relevant to several physiopathological conditions such as atherosclerosis or hypertension.
Collapse
Affiliation(s)
- Isabelle Bar
- Institute of Interdisciplinary Research, Institute of Biology and Molecular Medicine, Universite' Libre de Bruxelles, Gosselies, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Gui Y, Walsh MP, Jankowski V, Jankowski J, Zheng XL. Up4A stimulates endothelium-independent contraction of isolated rat pulmonary artery. Am J Physiol Lung Cell Mol Physiol 2008; 294:L733-8. [PMID: 18192588 DOI: 10.1152/ajplung.00403.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Extracellular nucleotides, such as ATP, UDP, and UTP, regulate pulmonary vascular tone through P2X and P2Y receptors. Recently, uridine adenosine tetraphosphate (Up(4)A) was reported as a novel endothelium-derived vasoconstrictive factor. Up(4)A contains both purine and pyrimidine moieties, which potentially activate P2X and P2Y receptors. The present study examined the effect of Up(4)A on contractility of isolated rat pulmonary artery. Up(4)A at 1-100 microM stimulated contraction in a concentration-dependent manner. Up(4)A was equipotent as UTP and UDP in the endothelium-denuded artery while much more effective than UTP and UDP in endothelium-intact preparations. The vasoconstrictor effect of Up(4)A was inhibited by suramin but not IP(5)I or desensitization of P2X receptors with alpha,beta-methylene-ATP (alpha,beta-Me-ATP). Up(4)A-induced contraction was also inhibited by pretreatment with thapsigargin, nitrendipine, or EGTA but unaffected by H1152. Furthermore, unlike ATP and UTP, Up(4)A did not induce relaxation of endothelium-intact preparations precontracted with phenylephrine. These results suggest that Up(4)A is a potent vasoconstrictor, but not a vasodilator, of the rat pulmonary artery. Up(4)A likely acts through a suramin-sensitive P2Y receptor. The contractile effect of Up(4)A involves the entry of extracellular Ca(2+) and release of Ca(2+) from intracellular stores but not Ca(2+) sensitization via the RhoA/Rho kinase pathway. Up(4)A, therefore, potentially plays an important role in the regulation of pulmonary vascular tone.
Collapse
Affiliation(s)
- Yu Gui
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | | | | | | | | |
Collapse
|
20
|
Rayment SJ, Latif ML, Ralevic V, Alexander SPH. Evidence for the expression of multiple uracil nucleotide-stimulated P2 receptors coupled to smooth muscle contraction in porcine isolated arteries. Br J Pharmacol 2007; 150:604-12. [PMID: 17262017 PMCID: PMC2189772 DOI: 10.1038/sj.bjp.0707120] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE The uracil nucleotides UDP and UTP have been reported to activate P2Y2, P2Y4 and P2Y6 receptors to cause vasoconstriction. We have performed a comparative analysis of these receptors in endothelium-denuded smooth muscle from porcine isolated coronary and ear arteries, using pharmacological and molecular tools. EXPERIMENTAL APPROACH Tissue segments were used to construct non-cumulative concentration response curves for UTP and UDP, in the absence and presence of the P2 receptor antagonists PPADS or suramin. RT-PCR and immunoblot analyses were employed to define gene expression and immunoreactivity for P2Y2, P2Y4 and P2Y6 receptors. KEY RESULTS In the coronary artery, UTP-evoked contractile responses were reduced in the presence of suramin, but not PPADS, while the smaller responses to UDP were unaffected by either antagonist. In the ear artery, contractile responses to UDP were much smaller than those to UTP; responses to UTP were inhibited by both PPADS and suramin. RT-PCR suggested predominant expression of P2Y2 receptors in the coronary artery, while P2Y4 and P2Y6 receptor gene expression appeared equivalent in both tissues. Immunoblot analyses provided evidence for P2Y6 receptors in both tissues, with equivocal evidence of P2Y2 and P2Y4 receptor immunoreactivities. CONCLUSIONS AND IMPLICATIONS We conclude that UTP-evoked contraction of porcine coronary artery smooth muscle appears to be predominantly P2Y2-mediated, while the ear artery appears to express a uracil nucleotide-sensitive P2 receptor(s) which fails to fit readily into the current classification.
Collapse
MESH Headings
- Animals
- Blotting, Western
- Coronary Vessels/metabolism
- Dose-Response Relationship, Drug
- Ear/blood supply
- Gene Expression
- In Vitro Techniques
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Purinergic P2 Receptor Agonists
- Pyridoxal Phosphate/analogs & derivatives
- Pyridoxal Phosphate/pharmacology
- RNA, Messenger/analysis
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y2
- Reverse Transcriptase Polymerase Chain Reaction
- Suramin/pharmacology
- Swine
- Uracil Nucleotides/metabolism
- Uracil Nucleotides/pharmacology
- Uridine Diphosphate/metabolism
- Uridine Triphosphate/metabolism
- Vasoconstriction/drug effects
Collapse
Affiliation(s)
- S J Rayment
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre Nottingham, UK
| | - M L Latif
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre Nottingham, UK
| | - V Ralevic
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre Nottingham, UK
| | - S P H Alexander
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre Nottingham, UK
- Author for correspondence:
| |
Collapse
|
21
|
Guns PJDF, Korda A, Crauwels HM, Van Assche T, Robaye B, Boeynaems JM, Bult H. Pharmacological characterization of nucleotide P2Y receptors on endothelial cells of the mouse aorta. Br J Pharmacol 2005; 146:288-95. [PMID: 15997227 PMCID: PMC1576272 DOI: 10.1038/sj.bjp.0706326] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Nucleotides regulate various effects including vascular tone. This study was aimed to characterize P2Y receptors on endothelial cells of the aorta of C57BL6 mice. Five adjacent segments (width 2 mm) of the thoracic aorta were mounted in organ baths to measure isometric force development. Nucleotides evoked complete (adenosine 5' triphosphate (ATP), uridine 5' triphosphate (UTP), uridine 5' diphosphate (UDP); >90%) or partial (adenosine 5' diphosphate (ADP)) relaxation of phenylephrine precontracted thoracic aortic rings of C57BL6 mice. Relaxation was abolished by removal of the endothelium and was strongly suppressed (>90%) by inhibitors of nitric oxide synthesis. The rank order of potency was: UDP approximately UTP approximately ADP>adenosine 5'-[gamma-thio] triphosphate (ATPgammaS)>ATP, with respective pD2 values of 6.31, 6.24, 6.22, 5.82 and 5.40. These results are compatible with the presence of P2Y1 (ADP>ATP), P2Y2 or P2Y4 (ATP and UTP) and P2Y6 (UDP) receptors. P2Y4 receptors were not involved, since P2Y4-deficient mice displayed unaltered responses to ATP and UTP. The purinergic receptor antagonist suramin exerted surmountable antagonism for all agonists. Its apparent pKb for ATP (4.53+/-0.07) was compatible with literature, but the pKb for UTP (5.19+/-0.03) was significantly higher. This discrepancy suggests that UTP activates supplementary non-P2Y2 receptor subtype(s). Further, pyridoxal-phosphate-6-azophenyl-2'-4'-disulphonic acid (PPADS) showed surmountable (UTP, UDP), nonsurmountable (ADP) or no antagonism (ATP). Finally, 2'-deoxy-N6-methyladenosine3',5'-bisphosphate (MRS2179) inhibited ADP-evoked relaxation only. Taken together, these results point to the presence of functional P2Y1 (ADP), P2Y2 (ATP, UTP) and P2Y6 (UDP) receptors on murine aorta endothelial cells. The identity of the receptor(s) mediating the action of UTP is not fully clear and other P2Y subtypes might be involved in UTP-evoked vasodilatation.
Collapse
MESH Headings
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Binding, Competitive/drug effects
- Dose-Response Relationship, Drug
- Endothelial Cells/drug effects
- In Vitro Techniques
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Nucleotides/pharmacology
- Purinergic P2 Receptor Agonists
- Purinergic P2 Receptor Antagonists
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/physiology
- Vasodilator Agents/pharmacology
Collapse
|
22
|
Tanneur V, Duranton C, Brand VB, Sandu CD, Akkaya C, Kasinathan RS, Gachet C, Sluyter R, Barden JA, Wiley JS, Lang F, Huber SM. Purinoceptors are involved in the induction of an osmolyte permeability in malaria-infected and oxidized human erythrocytes. FASEB J 2005; 20:133-5. [PMID: 16267125 DOI: 10.1096/fj.04-3371fje] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In human erythrocytes, infection by the malaria parasite Plasmodium falciparum or oxidative stress induces a new organic osmolyte and anion permeability. To examine a role for autocrine purinoceptor signaling during this induction process, erythrocytic purinoceptor expression, and ATP release were determined. Furthermore, using pharmacological and genetic approaches the dependence on purinoceptor signaling of osmolyte permeability and Plasmodium development, both in vitro and in vivo, were assessed. Extracellular ATP did not induce an osmolyte permeability in non-infected or non-oxidized erythrocytes. ATP and other purinoceptor agonists increased the induction of osmolyte permeability during infection or oxidation as measured by isosmotic hemolysis and patch-clamp recording. Purinoceptor antagonists and apyrase decreased the induced permeability. The observed pharmacology suggested the involvement of P2Y purinoceptors. Accordingly, human erythrocytes expressed P2Y1 protein. Moreover, P2Y1-deficient mouse erythrocytes exhibited a delayed appearance of the osmolyte permeability during P. berghei infection- or oxidation compared with wild-type erythrocytes. Furthermore, the nonspecific purinoceptor antagonist suramin decreased in vitro growth and DNA/RNA amplification of P. falciparum in human erythrocytes and decreased in vivo growth of P. berghei. P. berghei developed slower in P2Y1-deficient mice in vivo compared with wild-type animals. In conclusion, induction of the osmolyte permeability in Plasmodium-infected erythrocytes involves autocrine purinoceptor signaling.
Collapse
Affiliation(s)
- Valérie Tanneur
- Department of Physiology I, University of Tübingen, Tübingen, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Chootip K, Gurney AM, Kennedy C. Multiple P2Y receptors couple to calcium-dependent, chloride channels in smooth muscle cells of the rat pulmonary artery. Respir Res 2005; 6:124. [PMID: 16250909 PMCID: PMC1282591 DOI: 10.1186/1465-9921-6-124] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 10/26/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Uridine 5'-triphosphate (UTP) and uridine 5'-diphosphate (UDP) act via P2Y receptors to evoke contraction of rat pulmonary arteries, whilst adenosine 5'-triphosphate (ATP) acts via P2X and P2Y receptors. Pharmacological characterisation of these receptors in intact arteries is complicated by release and extracellular metabolism of nucleotides, so the aim of this study was to characterise the P2Y receptors under conditions that minimise these problems. METHODS The perforated-patch clamp technique was used to record the Ca2+-dependent, Cl- current (I(Cl,Ca)) activated by P2Y receptor agonists in acutely dissociated smooth muscle cells of rat small (SPA) and large (LPA) intrapulmonary arteries, held at -50 mV. Contractions to ATP were measured in isolated muscle rings. Data were compared by Student's t test or one way ANOVA. RESULTS ATP, UTP and UDP (10(-4) M) evoked oscillating, inward currents (peak = 13-727 pA) in 71-93% of cells. The first current was usually the largest and in the SPA the response to ATP was significantly greater than those to UTP or UDP (P < 0.05). Subsequent currents tended to decrease in amplitude, with a variable time-course, to a level that was significantly smaller for ATP (P < 0.05), UTP (P < 0.001) and UDP (P < 0.05) in the SPA. The frequency of oscillations was similar for each agonist (mean approximately to 6-11.min(-1)) and changed little during agonist application. The non-selective P2 receptor antagonist suramin (10(-4) M) abolished currents evoked by ATP in SPA (n = 4) and LPA (n = 4), but pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) (10(-4) M), also a non-selective P2 antagonist, had no effect (n = 4, 5 respectively). Currents elicited by UTP (n = 37) or UDP (n = 14) were unaffected by either antagonist. Contractions of SPA evoked by ATP were partially inhibited by PPADS (n = 4) and abolished by suramin (n = 5). Both antagonists abolished the contractions in LPA. CONCLUSION At least two P2Y subtypes couple to ICl,Ca in smooth muscle cells of rat SPA and LPA, with no apparent regional variation in their distribution. The suramin-sensitive, PPADS-resistant site activated by ATP most resembles the P2Y11 receptor. However, the suramin- and PPADS-insensitive receptor activated by UTP and UDP does not correspond to any of the known P2Y subtypes. These receptors likely play a significant role in nucleotide-induced vasoconstriction.
Collapse
Affiliation(s)
- Krongkarn Chootip
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 ONR, UK
- Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Alison M Gurney
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 ONR, UK
| | - Charles Kennedy
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 ONR, UK
| |
Collapse
|
24
|
Duval M, Beaudoin AR, Bkaily G, Gendron FP, D' Orléans-Juste P. Characterization of the NTPDase activities in the mesentery pre- and post-capillary circuits of the guinea pig. Can J Physiol Pharmacol 2003; 81:212-9. [PMID: 12733820 DOI: 10.1139/y03-043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NTPDase is one of the principal enzymes involved in the sequential hydrolysis of ATP. In the present study, the presence and functionality of NTPDase in the mesenteric vein and artery were examined. Adenosine triphosphate (ATP) (0.01-1000 pmol) induces a dose-dependent vasodilation in the isolated arterial and venous mesenteric vasculatures of the guinea pig. Adenosine diphosphate (ADP) (0.01-1000 pmol) but not adenosine monophosphate (AMP) (0.01-1000 pmol) induces a similar response in the mesenteric vascular circuit. L-NAME, a nitric oxide synthase inhibitor (200 microM, 30 min), significantly reduces the arterial dilatory effect of ATP and abolishes the responses to ADP and AMP. Complete removal of the endothelium with 3-[(3-cholamidopropyl) dimethylammonio]-1-propansulfonate (CHAPS) (20 mM, 2 x 45 s) abolishes ATP-induced responses. Infusion of ATP in the vascular circuit generated detectable amounts of ADP and AMP, as measured by HPLC. CHAPS treatment significantly reduced the level of ATP and the production of AMP in the arterial mesenteric circuit. In contrast to the arterial mesenteric vasculature, endothelium removal in the venous circuit triggered a marked potentiation of ADP release and, interestingly, a marked reduction in the release of AMP. Moreover, a specific inhibitor of NTP diphosphohydrolase, 1-hydroxynaphthlene-3,6-disulfonic acid BGO 136 (10 mM for 20 min), significatively reduced AMP production in both vascular preparations. These results confirm that the endothelium contributes to the vasoactive properties of ATP, ADP, and AMP. Our data also demonstrated a significant role of endothelium in NTPDase activity on ADP and AMP production prior to exogenous administration of ATP. The activity of this particular enzyme appears to be different from the reaction products viewpoint (i.e., the production of ADP) in the pre- and post-mesenteric circuits, suggesting two different isoforms with different substrate specificities.
Collapse
Affiliation(s)
- M Duval
- Department of Pharmacology, Institute of Pharmacology of Sherbrooke, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | | | | | | | | |
Collapse
|
25
|
Price GD, Robertson SJ, Edwards FA. Long-term potentiation of glutamatergic synaptic transmission induced by activation of presynaptic P2Y receptors in the rat medial habenula nucleus. Eur J Neurosci 2003; 17:844-50. [PMID: 12603274 DOI: 10.1046/j.1460-9568.2003.02501.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A novel form of long-term potentiation of glutamatergic synaptic transmission is described in the rat medial habenula nucleus. It occurs when uridine 5'-triphosphate is bath applied at low micromolar concentrations and is prevented by Reactive Blue 2, suggesting that it is mediated by P2Y4 receptors. Uridine 5'-diphosphate can also cause such a Reactive Blue 2-sensitive potentiation, but at higher concentrations (200 microm), suggesting that this might also be an effect on the relatively uridine 5'-diphosphate-insensitive P2Y4 receptor. The potentiation is due to an increase in presynaptic release probability. It requires neither depolarization nor calcium influx postsynaptically and is thus probably non-Hebbian. When potentiation due to low concentrations of uridine 5'-triphosphate is inhibited in the presence of Reactive Blue 2, uridine 5'-triphosphate causes instead a significant inhibition of glutamate release. We suggest that this inhibition may be mediated by a Reactive Blue 2-insensitive P2Y2-like receptor. At higher concentrations of uridine 5'-triphosphate (200 micro m), the inhibitory effect dominates such that even in the absence of Reactive Blue 2 no potentiation is seen.
Collapse
Affiliation(s)
- Gareth D Price
- Department of Physiology, University College London, Gower St, London WC1E 6BT, UK
| | | | | |
Collapse
|
26
|
Chootip K, Ness KF, Wang Y, Gurney AM, Kennedy C. Regional variation in P2 receptor expression in the rat pulmonary arterial circulation. Br J Pharmacol 2002; 137:637-46. [PMID: 12381677 PMCID: PMC1573537 DOI: 10.1038/sj.bjp.0704915] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Accepted: 08/06/2002] [Indexed: 11/09/2022] Open
Abstract
The P2 receptors that mediate contraction of the rat isolated small (SPA, 200-500 micro m i.d.) and large (LPA, 1-1.5 mM i.d.) intrapulmonary arteries were characterized. 2 In endothelium-denuded vessels the contractile order of potency was alpha,beta-methyleneATP (alpha,beta-meATP)>>UDP=UTP=ATP=2-methylthioATP>ADP in the SPA and alpha,beta-meATP=UTP>or=UDP>2-methylthioATP, ATP>>ADP in the LPA. alpha,beta-meATP, 2-methylthioATP and ATP had significantly greater effects in the SPA than the LPA (P<0.001), but there was no difference in the potency of UTP or UDP between the vessels. 3 In the SPA, P2X1 receptor desensitisation by alpha,beta-meATP (100 microM) inhibited contractions to alpha,beta-meATP (10 nM-300 microM), but not those to UTP or UDP (100 nM-300 microM). In the LPA, prolonged exposure to alpha,beta-meATP (100 microM) did not desensitize P2X receptors. 4 Pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS), suramin and reactive blue 2 (RB2) (30-300 microM) inhibited contractions evoked by alpha,beta-meATP. UTP and UDP were potentiated by PPADS, unaffected by RB2 and inhibited, but not abolished by suramin. 1 and 3 mM suramin produced no further inhibition, indicating suramin-resistant components in the responses to UTP and UDP. 5 Thus, both P2X and P2Y receptors mediate contraction of rat large and small intrapulmonary arteries. P2Y agonist potency and sensitivity to antagonists were similar in small and large vessels, but P2X agonists were more potent in small arteries. This indicates differential expression of P2X, but not P2Y receptors along the pulmonary arterial tree.
Collapse
Affiliation(s)
- K Chootip
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR
| | - K F Ness
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR
| | - Y Wang
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR
| | - A M Gurney
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR
| | - C Kennedy
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR
| |
Collapse
|
27
|
Buvinic S, Briones R, Huidobro-Toro JP. P2Y(1) and P2Y(2) receptors are coupled to the NO/cGMP pathway to vasodilate the rat arterial mesenteric bed. Br J Pharmacol 2002; 136:847-56. [PMID: 12110609 PMCID: PMC1573418 DOI: 10.1038/sj.bjp.0704789] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
1. To assess the role of nucleotide receptors in endothelial-smooth muscle signalling, changes in perfusion pressure of the rat arterial mesenteric bed, the luminal output of nitric oxide (NO) and guanosine 3',5' cyclic monophosphate (cGMP) accumulation were measured after the perfusion of nucleotides. 2. The rank order of potency of ATP and analogues in causing relaxation of precontracted mesenteries was: 2-MeSADP=2-MeSATP>ADP>ATP=UDP=UTP>adenosine. The vasodilatation was coupled to a concentration-dependent rise in NO and cGMP production. MRS 2179 selectively blocked the 2-MeSATP-induced vasodilatation, the NO surge and the cGMP accumulation, but not the UTP or ATP vasorelaxation. 3. mRNA encoding for P2Y(1), P2Y(2) and P2Y(6) receptors, but not the P2Y(4) receptor, was detected in intact mesenteries by RT-PCR. After endothelium removal, only P2Y(6) mRNA was found. 4. Endothelium removal or blockade of NO synthase obliterated the nucleotides-induced dilatation, the NO rise and cGMP accumulation. Furthermore, 2-MeSATP, ATP, UTP and UDP contracted endothelium-denuded mesenteries, revealing additional muscular P2Y and P2X receptors. 5. Blockade of soluble guanylyl cyclase reduced the 2-MeSATP and UTP-induced vasodilatation and the accumulation of cGMP without interfering with NO production. 6. Blockade of phosphodiesterases with IBMX increased 15-20 fold the 2-MeSATP and UTP-induced rise in cGMP; sildenafil only doubled the cGMP accumulation. A linear correlation between the rise in NO and cGMP was found. 7. Endothelial P2Y(1) and P2Y(2) receptors coupled to the NO/cGMP cascade suggest that extracellular nucleotides are involved in endothelial-smooth muscle signalling. Additional muscular P2Y and P2X receptors highlight the physiology of nucleotides in vascular regulation.
Collapse
MESH Headings
- Adenosine Diphosphate/analogs & derivatives
- Adenosine Diphosphate/pharmacology
- Animals
- Cyclic GMP/biosynthesis
- Cyclic GMP/physiology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiology
- Guanylate Cyclase
- Humans
- Luminescent Measurements
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/physiology
- Muscle, Smooth, Vascular/physiology
- Nitric Oxide/biosynthesis
- Nitric Oxide/physiology
- Nitric Oxide Synthase/antagonists & inhibitors
- Nucleotides/pharmacology
- Nucleotides/physiology
- Purinergic P2 Receptor Agonists
- Purinergic P2 Receptor Antagonists
- RNA, Messenger/biosynthesis
- Radioimmunoassay
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Purinergic P2/biosynthesis
- Receptors, Purinergic P2/physiology
- Receptors, Purinergic P2Y1
- Receptors, Purinergic P2Y2
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Soluble Guanylyl Cyclase
- Vasodilation/drug effects
- Vasodilation/physiology
Collapse
Affiliation(s)
- Sonja Buvinic
- Centro de Regulación Celular y Patología, Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Unidad de Regulación Neurohumoral, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
| | - René Briones
- Centro de Regulación Celular y Patología, Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Unidad de Regulación Neurohumoral, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
| | - J Pablo Huidobro-Toro
- Centro de Regulación Celular y Patología, Instituto Milenio de Biología Fundamental y Aplicada, MIFAB, Departamento de Fisiología, Unidad de Regulación Neurohumoral, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago 1, Chile
- Author for correspondence:
| |
Collapse
|
28
|
Sak K, Webb TE. A retrospective of recombinant P2Y receptor subtypes and their pharmacology. Arch Biochem Biophys 2002; 397:131-6. [PMID: 11747319 DOI: 10.1006/abbi.2001.2616] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the first cloning of P2Y receptor sequences in 1993 it has become apparent that this family of G-protein-coupled receptors is omnipresent. At least 25 individual sequences entered in the GenBank sequence database encode P2Y receptors from a variety of species ranging from the little skate Raja erinacea to man. In man, six receptor subtypes have been cloned and found to be functionally active (P2Y(1), P2Y(2), P2Y(4), P2Y(6), P2Y(11), and P2Y(12)). In this article a review of the P2Y receptor subtypes is presented considering both their sequences and the pharmacological profiles of the encoded receptors expressed in heterologous expression systems.
Collapse
Affiliation(s)
- Katrin Sak
- Hematology-Oncology Clinic, Tartu University, Ulikooli 18, Tartu 50090, Estonia
| | | |
Collapse
|
29
|
Nörenberg W, von Kügelgen I, Meyer A, Illes P, Starke K. M-type K+ currents in rat cultured thoracolumbar sympathetic neurones and their role in uracil nucleotide-evoked noradrenaline release. Br J Pharmacol 2000; 129:709-23. [PMID: 10683196 PMCID: PMC1571887 DOI: 10.1038/sj.bjp.0703096] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/1999] [Revised: 10/25/1999] [Accepted: 11/12/1999] [Indexed: 11/08/2022] Open
Abstract
Cultured sympathetic neurones are depolarized and release noradrenaline in response to extracellular ATP, UDP and UTP. We examined the possibility that, in neurones cultured from rat thoracolumbar sympathetic ganglia, inhibition of the M-type potassium current might underlie the effects of UDP and UTP. Reverse transcriptase-polymerase chain reaction indicated that the cultured cells contained mRNA for P2Y(2)-, P2Y(4)- and P2Y(6)-receptors as well as for the KCNQ2- and KCNQ3-subunits which have been suggested to assemble into M-channels. In cultures of neurones taken from newborn as well as from 10 day-old rats, oxotremorine, the M-channel blocker Ba(2+) and UDP all released previously stored [(3)H]-noradrenaline. The neurones possessed M-currents, the kinetic properties of which were similar in neurones from newborn and 9 - 12 day-old rats. UDP, UTP and ATP had no effect on M-currents in neurones prepared from newborn rats. Oxotremorine and Ba(2+) substantially inhibited the current. ATP also had no effect on the M-current in neurones prepared from 9 - 12 day-old rats. Oxotremorine and Ba(2+) again caused marked inhibition. In contrast to cultures from newborn animals, UDP and UTP attenuated the M-current in neurones from 9 - 12 day-old rats; however, the maximal inhibition was less than 30%. The results indicate that inhibition of the M-current is not involved in uracil nucleotide-induced transmitter release from rat cultured sympathetic neurones during early development. M-current inhibition may contribute to release at later stages, but only to a minor extent. The mechanism leading to noradrenaline release by UDP and UTP remains unknown.
Collapse
MESH Headings
- Adenosine Triphosphate/pharmacology
- Animals
- Barium/pharmacology
- Cells, Cultured
- Female
- Ganglia, Sympathetic/drug effects
- Ganglia, Sympathetic/metabolism
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Muscarinic Agonists/pharmacology
- Neurons/drug effects
- Neurons/metabolism
- Norepinephrine/metabolism
- Oxotremorine/pharmacology
- Patch-Clamp Techniques
- Potassium Channel Blockers
- Potassium Channels/classification
- Potassium Channels/physiology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, Purinergic P2/biosynthesis
- Receptors, Purinergic P2/classification
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Tritium
- Uridine Diphosphate/pharmacology
- Uridine Triphosphate/pharmacology
Collapse
Affiliation(s)
- W Nörenberg
- Pharmakologisches Institut, Universitat Freiburg, Hermann-Herder-Strasse 5, D-79104 Freiburg, Germany
| | | | | | | | | |
Collapse
|