The aim of this study is to investigate the effect of isosorbide-5-mononitrate (ISMN) on the electric field stimulation induced sympathetic purinergic vasoconstriction of the rabbit saphenous arterial rings. Isometric vasoconstrictive responses to electric field stimulation and to exogenous noradrenaline and adenosine triphosphate were recorded. We found that the vasoconstrictive responses to electric field stimulation (15 V, 1 ms pulse duration, 2 - 16 Hz) were frequency-dependant in the rabbit saphenous arterial rings, and abolished by tetrodotoxin (0.1 micromol x L(-1)). The alpha1-adrenoceptor antagonist prazosin (1 micromol x L(-1)) did not affect the vascular responses to the electric field stimulation (2 -8 Hz). After a combination treatment with both alpha,beta-meATP (3 micromol x L(-1), desensitizing P2X1 receptors) and prazosin (1 micromol x L(-1)), the vasoconstrictive responses to electric field stimulation were abolished. When the arterial preparation was treated with ISMN (one preparation was exposed to only one concentration of ISMN), ISMN at 0.1 mmol x L(-1) significantly inhibited the vasoconstriction induced by electric stimulation at 8 Hz, 0.3 and 1.0 mmol x L(-1) significantly inhibited the vasoconstrictive responses to electric stimulation at 2 - 16 Hz. The highest concentration of ISMN (1.0 mmol x L(-1)) reduced the vasoconstrictive responses by 46% (2 Hz), 47% (4 Hz), 34% (8 Hz) and 22% (16 Hz), separately. ISMN (0.3 and 1.0 mmol x L(-1)) did not affect the vascular responses to exogenous noradrenaline (0.01-100 micromol x L(-1)) and adenosine triphosphate (1 mmol x L(-1)). It is reasonable to suggest that ISMN inhibits the purinergic vasoconstriction induced by sympathetic nerve stimulation via a prejunctional mechanism.
Adenosine Triphosphate ; analogs & derivatives ; pharmacology ; Adrenergic alpha-Antagonists ; pharmacology ; Animals ; Arteries ; drug effects ; Delayed-Action Preparations ; Electric Stimulation ; Isosorbide Dinitrate ; administration & dosage ; analogs & derivatives ; pharmacology ; Male ; Norepinephrine ; pharmacology ; Prazosin ; pharmacology ; Purinergic P2 Receptor Agonists ; Rabbits ; Receptors, Purinergic P2X ; Vasoconstriction ; drug effects

BACKGROUNDThe mechanism of the neural injury caused by chronic intermittent hypoxia (CIH) that characterizes obstructive sleep apnea syndrome (OSAS) is not clearly known. The purpose of this study was to investigate whether P2X7 receptor (P2X7R) is responsible for the CIH-induced neural injury and the possible pathway it involves.

METHODSEight-week-old male C57BL/6 mice were used. For each exposure time point, eight mice divided in room air (RA) and IH group were assigned to the study of P2X7R expression. Whereas in the 21 days-Brilliant Blue G (BBG, a selective P2X7R antagonist) study, 48 mice were randomly divided into CIH group, BBG-treated CIH group, RA group and BBG-treated RA group. The hippocampus P2X7R expression was determined by Western blotting and real-time polymerase chain reaction (PCR). The spatial learning was analyzed by Morris water maze. The nuclear factor kappa B (NFκB) and NADPH oxidase 2 (NOX2) expressions were analyzed by Western blotting. The expressions of tumor necrosis factor α, interleukin 1β (IL-β), IL-18, and IL-6 were measured by real-time PCR. The malondialdehyde and superoxide dismutase levels were detected by colorimetric method. Cell damage was evaluated by Hematoxylin and Eosin staining and Terminal Transferase dUTP Nick-end Labeling method.

RESULTSThe P2X7R mRNA was elevated and sustained after 3-day IH exposure and the P2X7R protein was elevated and sustained after 7-day IH exposure. In the BBG study, the CIH mice showed severer neuronal cell damage and poorer performance in the behavior test. The increased NFκB and NOX2 expressions along with the inflammation injury and oxidative stress were also observed in the CIH group. BBG alleviated CIH-induced neural injury and consequent functional deficits.

CONCLUSIONSThe P2X7R antagonism attenuates the CIH-induced neuroinflammation, oxidative stress, and spatial deficits, demonstrating that the P2X7R is an important therapeutic target in the cognition deficits accompanied OSAS.

Animals ; Disease Models, Animal ; Hypoxia ; Male ; Metabolic Networks and Pathways ; Mice ; Mice, Inbred C57BL ; Purinergic P2 Receptor Antagonists ; pharmacology ; Receptors, Purinergic P2X7 ; analysis ; physiology ; Rosaniline Dyes ; pharmacology ; Sleep Apnea, Obstructive ; metabolism

Previously we demonstrated that ATP released from LPS-activated microglia induced IL-10 expression in a process involving P2 receptors, in an autocrine fashion. Therefore, in the present study we sought to determine which subtype of P2 receptor was responsible for the modulation of IL-10 expression in ATP-stimulated microglia. We found that the patterns of IL-10 production were dose-dependent (1, 10, 100, 1,000 micrometer) and bell-shaped. The concentrations of ATP, ATP-gammaS, ADP, and ADP-beta S that showed maximal IL-10 release were 100, 10, 100, and 100 micrometer respectively. The rank order of agonist potency for IL-10 production was 2'-3'-O-(4-benzoyl)-benzoyl ATP (BzATP) = dATP > 2-methylthio-ADP (2-meSADP). On the other hand, 2-methylthio-ATP (2-meSATP), alpha,beta-methylene ATP (alpha,beta-meATP), UTP, and UDP did not induce the release of IL-10 from microglia. Further, we obtained evidence of crosstalk between P2 receptors, in a situation where intracellular Ca2+ release and/or cAMP-activated PKA were the main contributors to extracellular ATP-(or ADP)-mediated IL-10 expression, and IL-10 production was down- regulated by either MRS2179 (a P2Y1 antagonist) or 5'-AMPS (a P2Y11 antagonist), indicating that both the P2Y1 and P2Y11 receptors are major receptors involved in IL-10 expression. In addition, we found that inhibition of IL-10 production by high concentrations of ATP-gammaS (100 micrometer) was restored by TNP-ATP (an antagonist of the P2X1, P2X3, and P2X4 receptors), and that IL-10 production by 2-meSADP was restored by 2meSAMP (a P2Y12 receptor antagonist) or pertusis toxin (PTX; a Gi protein inhibitor), indicating that the P2X1, P2X3, P2X4 receptor group, or the P2Y12 receptor, negatively modulate the P2Y11 receptor or the P2Y1 receptor, respectively.
Adenosine Diphosphate/analogs & derivatives/pharmacology ; Adenosine Triphosphate/analogs & derivatives/*pharmacology ; Adenylate Cyclase/antagonists & inhibitors ; Animals ; Calcium/metabolism ; Chelating Agents/pharmacology ; Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors ; Enzyme Inhibitors/pharmacology ; Extracellular Space/drug effects/*metabolism ; Gene Expression Regulation/drug effects ; Interleukin-10/*biosynthesis ; Microglia/*drug effects/enzymology/*metabolism ; RNA, Messenger/genetics/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor Cross-Talk/*drug effects ; Receptors, Purinergic P2/agonists/antagonists & inhibitors/genetics/*metabolism ; Thionucleotides/pharmacology

OBJECTIVETo investigate P2Y purinergic receptor activated PI-3K/Akt signaling pathway in the regulation of growth and invasion of prostate cancer in vitro.

METHODSWestern blot was used to detect phosphorylation of Akt (a downstream target molecule of PI-3K) by P2Y receptor agonist in 1E8 cells (a highly metastatic subclone derived from PC-3 prostatic cancer cell line). Cell counts, flow cytometry, Matrigel invasion assay, wound healing assay and gelatin zymography were used to detect changes of biological behaviors of 1E8 cells after P2Y receptor activation.

RESULTSAMP-PNP, one non-hydrolysis ATP analogue and P2Y receptor agonist, induced significant phosphorylation of Akt in a time- and dose-dependent manner in IE8 cells. LY294002, a specific inhibitor of PI-3K, effectively blocked Akt phosphorylation induced by AMP-PNP. Continuous exposure to AMP-PNP induced significant growth inhibition of 1E8 cells (inhibition rate at 50.2% at the 8th day), and this inhibition was mainly due to an arrest at S phase of the cell cycle (the S phase fraction of AMP-PNP treated cells was 22.3% higher than that of the control). Application of LY294002 did not reverse the growth inhibition effect of AMP-PNP. Matrigel invasion assay showed that AMP-PNP stimulation increased invasive ability of 1E8 cells, and this effect was effectively blocked by LY294002. No significant changes in the activation of MMP-2 and MMP-9 were detected by gelatin zymography, although wound healing assay showed 21.2% increase in cell migration after AMP-PNP treatment.

CONCLUSIONSPI-3K/Akt signaling pathway participates in P2Y receptor-stimulated prostate cancer invasion by enhancing cell motility, rather than up-regulating MMP-2 and MMP-9 activities. PI-3K signaling pathway plays an important role in prostate cancer proliferation, but is not involved in P2Y receptor mediated growth inhibition.

Adenylyl Imidodiphosphate ; pharmacology ; Animals ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Chromones ; pharmacology ; Humans ; Male ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Mice ; Mice, Nude ; Morpholines ; pharmacology ; Neoplasm Invasiveness ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Phosphorylation ; Prostatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism ; Purinergic P2 Receptor Agonists ; S Phase ; drug effects ; Signal Transduction ; drug effects

No abstract available.
Korea* ; Myocardial Infarction* ; Purinergic P2Y Receptor Antagonists*

Purinergic P2Y Receptor Antagonists ; Consensus ; Cardiovascular System ; Cardiology ; Asia

BACKGROUND AND OBJECTIVES: Increased bleeding rates with standard dose prasugrel have led to increased questions about the effectiveness and safety of the lower maintenance dose. We compared platelet inhibitory efficacy between low dose prasugrel and standard dose clopidogrel in patients on maintenance dose dual antiplatelet therapy. SUBJECTS AND METHODS: Forty-three patients who underwent percutaneous coronary intervention were randomized to receive 75 mg clopidogrel (n=23) or 5 mg prasugrel (n=20). Another 20 patients were allocated to 10 mg prasugrel as a reference comparison group. All patients (weight, > or =60 kg; age, <75 years) had been receiving 100 mg aspirin and 75 mg clopidogrel daily. The platelet function test was performed at baseline and 30 days after randomization. The primary endpoint was P2Y12 reaction unit (PRU) at 30 days between 5 mg prasugrel and 75 mg clopidogrel. RESULTS: No differences in baseline PRU values were observed among the three groups. The prasugrel (5 mg) group had a significantly lower PRU value compared with that of 75 mg clopidogrel (174.6+/-60.2 vs. 223.4+/-72.9, p=0.022) group at 30 days, whereas the 10 mg prasugrel group showed a lower PRU value (71.9+/-34.4) compared with that of the 5 mg prasugrel (p<0.001). The rate of high on-treatment platelet reactivity (PRU >235) was significant lower in the 5 mg prasugrel group than that in the 75 mg clopidogrel group (15.0% vs. 56.5%, p=0.010). CONCLUSION: Prasugrel (5 mg) is more potent antiplatelet therapy than 75 mg clopidogrel in non-low body weight and non-elderly patients on a maintenance dose dual antiplatelet therapy.
Aspirin ; Body Weight ; Hemorrhage ; Humans ; Percutaneous Coronary Intervention* ; Platelet Function Tests ; Purinergic P2Y Receptor Antagonists ; Random Allocation ; Prasugrel Hydrochloride

BACKGROUND/AIMS: Platelet counts and characteristics can influence platelet reactivity during antiplatelet therapy. We compared the effects of both platelet count and indices on platelet reactivity between patients who were treated with either clopodogrel or ticagrelor. METHODS: Patients with coronary artery disease who underwent percutaneous coronary intervention were randomly assigned to either the clopidogrel (n = 63) or ticagrelor (n = 65) groups. Platelet count, platelet indices (including mean platelet volume, platelet distribution width, platelet large cell ratio, and immature platelet fraction), and platelet reactivity were measured before intervention, and 48 hours and 30 days post-intervention. High on-treatment platelet reactivity (HPR) was defined as ≥ 47 unit as assessed by multiple electrode platelet aggregometry. RESULTS: Baseline platelet reactivity was similar between the two groups; however, at 48 hours and 30 days, platelet reactivity was significantly lower in the ticagrelor group than in the clopidogrel group. Platelet count, mean platelet volume, platelet distribution width, platelet large cell ratio, and immature platelet fraction were significantly correlated with platelet reactivity in the clopidogrel group; however, these correlations were attenuated in the ticagrelor group. The use of clopodogrel (hazard ratio [HR] 4.1, 95% confidence interval [CI] 1.4–11.9; p = 0.010) and platelet count (HR 9.7, 95% CI 2.9–32.7; p = 0.001) were independent predictors for 30 day HPR. Platelet count was an independent predictor of HPR in the clopidogrel group but not in the ticagrelor group. CONCLUSIONS: Platelet count and indices are significantly correlated with platelet reactivity. However, antiplatelet treatment with ticagrelor could overcome these associations.
Blood Platelets* ; Coronary Artery Disease ; Electrodes ; Humans ; Mean Platelet Volume ; Percutaneous Coronary Intervention ; Platelet Count* ; Platelet Function Tests ; Purinergic P2Y Receptor Antagonists

To explore novel ADP receptor inhibitors with anti-thrombotic activity, eighteen compounds were synthesized and their structures were confirmed by 1H NMR and MS. The results showed that the activity of compound C1 was superior to ticlopidine in platelet aggregation inhibition tests in vivo and worthy for further investigation. Compounds A4, B2, C4 and C7 possessed moderate platelet aggregation inhibitory activities.
Animals ; Male ; Molecular Structure ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; chemical synthesis ; chemistry ; pharmacology ; Purinergic P2Y Receptor Antagonists ; chemical synthesis ; chemistry ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Thienopyridines ; chemical synthesis ; chemistry ; pharmacology

Acute Coronary Syndrome/drug therapy* ; Aged ; Clopidogrel/therapeutic use* ; Humans ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors/therapeutic use* ; Purinergic P2Y Receptor Antagonists/therapeutic use* ; Ticagrelor/therapeutic use* ; Treatment Outcome