Comparative In Vitro Study of Various α2-Adrenoreceptor Agonist Drugs for Ticagrelor Reversal

Ticagrelor, an antiplatelet adenosine diphosphate (ADP)-P2Y12 receptor antagonist, increases the risk of bleeding. Its management is challenging because platelet transfusion is ineffective and no specific antidote is currently available. Epinephrine, a vasopressor catecholamine prescribed during shock, restores platelet functions inhibited by ticagrelor through stimulation of α2A-adrenoreceptors. It subsequently inhibits cyclic adenosine monophosphate (cAMP) pathway and PI3K signaling. However, since epinephrine may expose a patient to deleterious hemodynamic effects, we hypothesized that other α2-adrenoreceptor agonist drugs used in clinical practice with fewer side effects could reverse the antiplatelet effects of ticagrelor. We compared in vitro the efficacy of clonidine, dexmedetomidine, brimonidine, and norepinephrine with epinephrine to restore ADP- and PAR-1-AP-induced washed platelet aggregation inhibited by ticagrelor, as well as resulting platelet cAMP levels. In ticagrelor-free samples, none of the α2-adrenoreceptor agonists induced aggregation by itself but all of them potentiated ADP-induced aggregation. Compared with epinephrine, norepinephrine, and brimonidine partially restored ADP- and fully restored PAR-1-AP-induced aggregation inhibited by ticagrelor while clonidine and dexmedetomidine were ineffective. Indeed, this lack of effect resulted from a lower decrease in cAMP concentration elicited by these partial α2-adrenoreceptor agonists, clonidine, and dexmedetomidine, compared with full α2-agonists. Our results support the development of specific full and systemic α2-adrenoreceptor agonists for ticagrelor reversal.

Download Full-text

Differential requirements for platelet aggregation and inhibition of adenylate cyclase by epinephrine. Studies of a familial platelet alpha 2-adrenergic receptor defect

Blood ◽

10.1182/blood.v71.2.494.494 ◽

1988 ◽

Vol 71 (2) ◽

pp. 494-501 ◽

Cited By ~ 42

Author(s):

AK Rao ◽

J Willis ◽

MA Kowalska ◽

YT Wachtfogel ◽

RW Colman

Keyword(s):

Platelet Aggregation ◽

Adenylate Cyclase ◽

Adrenergic Receptors ◽

Adrenergic Receptor ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Adenosine Diphosphate ◽

Normal Subjects ◽

Camp Levels ◽

Epinephrine Concentration

Abstract We describe a family whose members have impaired platelet aggregation and secretion responses to epinephrine with normal responses to adenosine diphosphate and collagen. Platelet alpha 2-adrenergic receptors (measured using 3H methyl-yohimbine) were diminished in the propositus (78 sites per platelet), his two sisters (70 and 27 sites per platelet), and parents (37 and 63 sites per platelet), but not in two maternal aunts (12 normal subjects, 214 +/- 18 sites per platelet; mean +/- SE). However, the inhibition of cyclic adenosine monophosphate (cAMP) levels by epinephrine in platelets exposed to 400 nmol/L PGI2 was similar in the patients and five normal subjects (epinephrine concentration for 50% inhibition, 0.04 +/- 0.01 mumol/L v 0.03 +/- 0.01 mumol/L; P greater than .05). In normal platelets, the concentration of yohimbine (0.18 mumol/L) required for half maximal inhibition of aggregation induced by 2 mumol/L epinephrine was lower than that for inhibition of its effect on adenylate cyclase (1.6 mumol/L). In quin2 loaded platelets, thrombin (0.1 U/mL) stimulated rise in cytoplasmic Ca2+ concentration, [Ca2+]i, was normal in the two patients studied. The PGI2 analog ZK 36,374 completely inhibited thrombin-induced rise in [Ca2+]i; the reversal of this inhibition by epinephrine was normal in the two patients. Thus, despite the impaired aggregation response to epinephrine, platelets from these patients have normal ability to inhibit PGI2-stimulated cAMP levels. These patients with an inherited receptor defect provide evidence that fewer platelet alpha 2-adrenergic receptors are required for epinephrine-induced inhibition of adenylate cyclase than for aggregation.

Download Full-text

Genetic Polymorphisms of the ß2-Adrenergic Receptor Relate to Guanosine Protein-coupled Stimulator Receptor Dysfunction in Fibromyalgia Syndrome

The Journal of Rheumatology ◽

10.3899/jrheum.101104 ◽

2011 ◽

Vol 38 (6) ◽

pp. 1095-1103 ◽

Cited By ~ 17

Author(s):

YANGMING XIAO ◽

WEIJING HE ◽

I. JON RUSSELL

Keyword(s):

Adrenergic Receptor ◽

Fibromyalgia Syndrome ◽

Mononuclear Cells ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Intracellular Camp ◽

Peripheral Blood Mononuclear ◽

Genotype Frequencies ◽

Camp Levels

Objective.To determine the genotype frequencies of ß2-adrenergic receptor (ß2AR) gene polymorphisms (Gly16Arg, Glu27Gln) in patients with fibromyalgia syndrome (FM) by comparison with unrelated healthy controls. We sought any clinical association with these polymorphisms and determined whether the polymorphisms would associate with a biologic guanosine protein-coupled stimulator receptor (Gs) dysfunction in FM.Methods.Study subjects included 97 clinically characterized patients with FM and 59 controls. The ß2AR polymorphisms at codons 16 and 27 were determined using polymerase chain reaction-restriction fragment length polymorphism. The Gs functions of peripheral blood mononuclear cells (PBMC) were tested using isoproterenol (ISO) as the adrenergic Gs ligand and measuring intracellular cyclic adenosine monophosphate (cAMP) levels.Results.The frequency of the ß2AR gene polymorphism Gly16Arg in FM (43.5%) was significantly lower than in controls (63.2%), suggesting that this genotype might have some effect on the risk of developing FM. The only clinical association in FM was with sleep dysfunction. Patients with FM who carried the ß2AR polymorphism Arg16Arg also exhibited significantly lower PBMC basal cAMP levels (p < 0.05) and lower ISO-stimulated cAMP levels (p < 0.05) than FM carrying Gly16Gly or Gly16Arg.Conclusion.This confirms a relationship between ß2AR polymorphism and FM. It is the first study to demonstrate ß2AR polymorphism-related differences in intracellular cAMP responses of FM PBMC after ß2AR stimulationin vitro. These findings may explain some of the differences in responsiveness of FM subgroups to the adrenergic agonist medications currently approved for FM treatment.

Download Full-text

285 REGULATION OF OOCYTE MEIOTIC RESUMPTION USING cAMP MODULATORS IN BOVINE IN VITRO MATURATION

Reproduction Fertility and Development ◽

10.1071/rdv27n1ab285 ◽

2015 ◽

Vol 27 (1) ◽

pp. 231 ◽

Cited By ~ 1

Author(s):

S. E. Farmer ◽

J. A. Sarmiento-Guzmán ◽

C. L. Bailey ◽

K. R. Bondioli

Keyword(s):

In Vitro Maturation ◽

Transvaginal Ultrasound ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Cumulus Cells ◽

Current Experiment ◽

Negative Effect ◽

Low Efficiency ◽

Camp Levels

In vitro maturation (IVM) is a reproductive technique critical to in vitro embryo production (IVP). Currently, IVP has low efficiency due to an inadequate IVM system where premature meiotic resumption results in low oocyte viability. Meiotic arrest is regulated primarily by 3′,5′-cyclic adenosine monophosphate (cAMP). Some successful methods of improving IVM have utilised cAMP modulators to maintain high intraoocyte cAMP, delaying the onset of nuclear maturation and allowing cytoplasmic maturation to occur. The current experiment is a follow-up to previous work in which an extended 2-step maturation system was examined. In the previous experiments, we found that meiotic resumption was significantly delayed, but the overall maturation rates of extended IVM were about half those of standard IVM, suggesting that the effects of the modulators on the oocytes were not completely reversible. The current experiment compares cAMP concentrations of oocytes in this extended IVM to standard IVM to determine whether high cAMP is the cause of the low maturation rate. Bovine oocytes (n = 686) were obtained from mixed-breed cattle by transvaginal ultrasound-guided aspiration. Oocytes from each cow were divided into 2 groups: standard IVM and extended IVM. Standard IVM consists of a 23-h maturation composed of TCM-199 supplemented with 10% fetal bovine serum, sodium pyruvate, pen/strep, glutamine, and FSH, and cultured at 39°C in 5% CO2. Extended IVM consists of 2 steps: a pre-IVM phase composed of HEPES-TALP supplemented with 100 µM forskolin (FSK) and 500 µM 3-isobutyl-1-methylxanthine (IBMX) for 2 h at 39°C, followed by an extended IVM phase composed of standard IVM media supplemented with 20 µM cilostamide for 31 h (39°C, 5% CO2). Additionally, oocytes in the extended IVM treatment group where held in HEPES-TALP media with FSK and IBMX during the 2-h oocyte collection period in order to prevent any decrease in cAMP before the oocytes could be placed in the extended IVM media. Oocytes in standard IVM were sampled at 0, 8, and 23 h of maturation, while oocytes in extended IVM were sampled at 0, 8, 18, and 33 h of maturation. Cumulus cells were removed from all oocytes by vortexing in hyaluronidase solution. Oocytes were stored in groups of 10 at –80°C. A cAMP enzyme immunoassay (GE Healthcare) was performed to determine cAMP concentrations throughout standard and extended IVM. Assay results were analysed using an ANOVA followed by a Tukey's pairwise test (Sigma Stat 3.5) to detect significant differences (P < 0.05). Results indicated significantly higher cAMP levels in extended IVM oocytes during the first 3 h after collection using FSK and IBMX in the holding media (0.505 v. 1.006 fmol/oocyte, P = 0.035) but cAMP levels were not maintained in the cilostamide-only extended IVM medium. This suggests that high cAMP levels were not the cause of low maturation rates in extended IVM, since cAMP concentrations did decrease after 3 h. Possible negative effect of cilostamide on these oocytes may be suggested and need to be analysed.

Download Full-text

Rocuronium Has a Suppressive Effect on Platelet Function via the P2Y12 Receptor Pathway In Vitro That Is Not Reversed by Sugammadex

International Journal of Molecular Sciences ◽

10.3390/ijms21176399 ◽

2020 ◽

Vol 21 (17) ◽

pp. 6399

Author(s):

Yutaka Murata ◽

Shuji Kawamoto ◽

Kazuhiko Fukuda

Keyword(s):

Platelet Aggregation ◽

Muscle Relaxation ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Suppressive Effect ◽

P2y12 Receptor ◽

Receptor Signaling Pathway ◽

Morpholine Ring ◽

Platelet Functions

Rocuronium is an aminosteroid nondepolarizing neuromuscular blocker that is widely used for anesthesia and intensive care. In this study, we investigated the effect of rocuronium on human platelet functions in vitro. The effects of rocuronium on platelet aggregation, P-selectin expression, and cyclic adenosine monophosphate (cAMP) levels in platelets were measured using an aggregometer, an enzyme immunoassay, and flow cytometry, respectively. Rocuronium inhibited ADP-induced platelet aggregation, P-selectin expression and suppression of cAMP production. These effects were not antagonized by equimolar sugammadex, a synthetic γ-cyclodextrin derivative that antagonizes rocuronium-induced muscle relaxation by encapsulating the rocuronium molecule. Morpholine, which constitutes a part of the rocuronium molecule but is not encapsulated by sugammadex, inhibited ADP-induced platelet aggregation. Vecuronium, which has a molecular structure similar to that of rocuronium but does not possess a morpholine ring, had no significant effect on ADP-induced platelet aggregation. These results indicate that rocuronium has a suppressive effect on platelet functions in vitro that is not reversed by sugammadex and suggest that this effect is mediated by blockade of the P2Y12 receptor signaling pathway via the morpholine ring of rocuronium.

Download Full-text

Differential requirements for platelet aggregation and inhibition of adenylate cyclase by epinephrine. Studies of a familial platelet alpha 2-adrenergic receptor defect

Blood ◽

10.1182/blood.v71.2.494.bloodjournal712494 ◽

1988 ◽

Vol 71 (2) ◽

pp. 494-501

Author(s):

AK Rao ◽

J Willis ◽

MA Kowalska ◽

YT Wachtfogel ◽

RW Colman

Keyword(s):

Platelet Aggregation ◽

Adenylate Cyclase ◽

Adrenergic Receptors ◽

Adrenergic Receptor ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Adenosine Diphosphate ◽

Normal Subjects ◽

Camp Levels ◽

Epinephrine Concentration

We describe a family whose members have impaired platelet aggregation and secretion responses to epinephrine with normal responses to adenosine diphosphate and collagen. Platelet alpha 2-adrenergic receptors (measured using 3H methyl-yohimbine) were diminished in the propositus (78 sites per platelet), his two sisters (70 and 27 sites per platelet), and parents (37 and 63 sites per platelet), but not in two maternal aunts (12 normal subjects, 214 +/- 18 sites per platelet; mean +/- SE). However, the inhibition of cyclic adenosine monophosphate (cAMP) levels by epinephrine in platelets exposed to 400 nmol/L PGI2 was similar in the patients and five normal subjects (epinephrine concentration for 50% inhibition, 0.04 +/- 0.01 mumol/L v 0.03 +/- 0.01 mumol/L; P greater than .05). In normal platelets, the concentration of yohimbine (0.18 mumol/L) required for half maximal inhibition of aggregation induced by 2 mumol/L epinephrine was lower than that for inhibition of its effect on adenylate cyclase (1.6 mumol/L). In quin2 loaded platelets, thrombin (0.1 U/mL) stimulated rise in cytoplasmic Ca2+ concentration, [Ca2+]i, was normal in the two patients studied. The PGI2 analog ZK 36,374 completely inhibited thrombin-induced rise in [Ca2+]i; the reversal of this inhibition by epinephrine was normal in the two patients. Thus, despite the impaired aggregation response to epinephrine, platelets from these patients have normal ability to inhibit PGI2-stimulated cAMP levels. These patients with an inherited receptor defect provide evidence that fewer platelet alpha 2-adrenergic receptors are required for epinephrine-induced inhibition of adenylate cyclase than for aggregation.

Download Full-text

Effects of Bupranolol, a New β-Blocker, on Platelet Functions of Rabbit and Human in Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648052 ◽

1976 ◽

Vol 36 (02) ◽

pp. 376-387 ◽

Cited By ~ 3

Author(s):

Teruhiko Umetsu ◽

Kazuko Sanai ◽

Tadakatsu Kato

Keyword(s):

Platelet Aggregation ◽

Platelet Adhesion ◽

Human Platelets ◽

Rabbit Platelet ◽

Rabbit Platelets ◽

Β Blocker ◽

Platelet Aggregates ◽

Induced Aggregation ◽

Platelet Functions

SummaryThe effects of bupranolol, a new β-blocker, on platelet functions were investigated in vitro in rabbits and humans as compared with propranolol, a well-known β-blocker. At first, the effect of adrenaline on ADP-induced rabbit platelet aggregation was studied because adrenaline alone induces little or no aggregation of rabbit platelets. Enhancement of ADP-induced rabbit platelet aggregation by adrenaline was confirmed, as previously reported by Sinakos and Caen (1967). In addition the degree of the enhancement was proved to be markedly affected by the concentration of ADP and to increase with decreasing concentration of ADP, although the maximum aggregation (percent) was decreased.Bupranolol and propranolol inhibited the (adrenaline-ADP-)induced aggregation of rabbit platelets, bupranolol being approximately 2.4–3.2 times as effective as propranolol. Bupranolol stimulated the disaggregation of platelet aggregates induced by a combination of adrenaline and ADP, but propranolol did not. Platelet adhesion in rabbit was also inhibited by the β-blockers and bupranolol was more active than propranolol. With human platelets, aggregation induced by adrenaline was inhibited by bupranolol about 2.8–3.3 times as effectively as propranolol.From these findings. We would suggest that bupranolol might be useful for prevention or treatment of thrombosis.

Download Full-text

Anti-Allergic and Anti-Inflammatory Effects of Undecane on Mast Cells and Keratinocytes

Molecules ◽

10.3390/molecules25071554 ◽

2020 ◽

Vol 25 (7) ◽

pp. 1554

Author(s):

Dabin Choi ◽

Wesuk Kang ◽

Taesun Park

Keyword(s):

Mast Cells ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Allergic Diseases ◽

Intracellular Camp ◽

Tnf Α ◽

Anti Inflammatory ◽

Skin Conditions ◽

Factor Α ◽

Camp Levels

The critical roles of keratinocytes and resident mast cells in skin allergy and inflammation have been highlighted in many studies. Cyclic adenosine monophosphate (cAMP), the intracellular second messenger, has also recently emerged as a target molecule in the immune reaction underlying inflammatory skin conditions. Here, we investigated whether undecane, a naturally occurring plant compound, has anti-allergic and anti-inflammatory activities on sensitized rat basophilic leukemia (RBL-2H3) mast cells and HaCaT keratinocytes and we further explored the potential involvement of the cAMP as a molecular target for undecane. We confirmed that undecane increased intracellular cAMP levels in mast cells and keratinocytes. In sensitized mast cells, undecane inhibited degranulation and the secretion of histamine and tumor necrosis factor α (TNF-α). In addition, in sensitized keratinocytes, undecane reversed the increased levels of p38 phosphorylation, nuclear factor kappaB (NF-κB) transcriptional activity and target cytokine/chemokine genes, including thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC) and interleukin-8 (IL-8). These results suggest that undecane may be useful for the prevention or treatment of skin inflammatory disorders, such as atopic dermatitis, and other allergic diseases.

Download Full-text

Dobutamine Antagonizes Epinephrine's Biochemical and Cardiotonic Effects

Anesthesiology ◽

10.1097/00000542-199807000-00010 ◽

1998 ◽

Vol 89 (1) ◽

pp. 49-57 ◽

Cited By ~ 29

Author(s):

Richard C. Prielipp ◽

Drew A. MacGregor ◽

Roger L. Royster ◽

Neal D. Kon ◽

Michael H. Hines ◽

...

Keyword(s):

Artery Bypass ◽

Phase 1 ◽

Human Lymphocytes ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Camp Production ◽

Isobolographic Analysis ◽

Camp Generation ◽

Vitro Model

Background Patients may receive more than one positive inotropic drug to improve myocardial function and cardiac output, with the assumption that the effects of two drugs are additive. The authors hypothesized that combinations of dobutamine and epinephrine would produce additive biochemical and hemodynamic effects. Methods The study was performed in two parts. Phase 1 used human lymphocytes in an in vitro model of cyclic adenosine monophosphate (cAMP) generation in response to dobutamine (10(-8) to 10(-4) M) or epinephrine (10(-9) M to 10(-5) M), and dobutamine and epinephrine together. Phase 2 was a clinical study in patients after aortocoronary artery bypass in which isobolographic analysis compared the cardiotonic effects of dobutamine (1.25, 2.5, or 5 microg x kg(-1) x min(-1)) or epinephrine (10, 20, or 40 ng x kg(-l) x min(-1)), alone or in combination. Results In phase 1, dobutamine increased cAMP production 41%, whereas epinephrine increased cAMP concentration approximately 200%. However, when epinephrine (10(-6) M) and dobutamine were combined, dobutamine reduced cAMP production at concentrations between 10(-6) to 10(-4) M (P = 0.001). In patients, 1.25 to 5 microg x kg(-1) x min(-1) dobutamine increased the cardiac index (CI) 15-28%. Epinephrine also increased the CI with each increase in dose. However, combining epinephrine with the two larger doses of dobutamine (2.5 and 5microg x kg(-1) x mi(-1)) did not increase the CI beyond that achieved with epinephrine and the lowest dose of dobutamine (1.25 microg x kg(-1) x min(-1)). In addition, the isobolographic analysis for equieffective concentrations of dobutamine and epinephrine suggests subadditive effects. Conclusions Dobutamine inhibits epinephrine-induced production of cAMP in human lymphocytes and appears to be subadditive by clinical and isobolographic analyses of the cardiotonic effects. These findings suggest that combinations of dobutamine and epinephrine may be less than additive.

Download Full-text

The nucleoporin RanBP2 tethers the cAMP effector Epac1 and inhibits its catalytic activity

The Journal of Cell Biology ◽

10.1083/jcb.201011126 ◽

2011 ◽

Vol 193 (6) ◽

pp. 1009-1020 ◽

Cited By ~ 33

Author(s):

Martijn Gloerich ◽

Marjolein J. Vliem ◽

Esther Prummel ◽

Lars A.T. Meijer ◽

Marije G.A. Rensen ◽

...

Keyword(s):

Catalytic Activity ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Negative Regulator ◽

Camp Signaling ◽

Nuclear Pore ◽

Nucleotide Exchange ◽

Nucleotide Exchange Factor ◽

Wide Range

Cyclic adenosine monophosphate (cAMP) is a second messenger that relays a wide range of hormone responses. In this paper, we demonstrate that the nuclear pore component RanBP2 acts as a negative regulator of cAMP signaling through Epac1, a cAMP-regulated guanine nucleotide exchange factor for Rap. We show that Epac1 directly interacts with the zinc fingers (ZNFs) of RanBP2, tethering Epac1 to the nuclear pore complex (NPC). RanBP2 inhibits the catalytic activity of Epac1 in vitro by binding to its catalytic CDC25 homology domain. Accordingly, cellular depletion of RanBP2 releases Epac1 from the NPC and enhances cAMP-induced Rap activation and cell adhesion. Epac1 also is released upon phosphorylation of the ZNFs of RanBP2, demonstrating that the interaction can be regulated by posttranslational modification. These results reveal a novel mechanism of Epac1 regulation and elucidate an unexpected link between the NPC and cAMP signaling.

Download Full-text

Isolated flagellar apparatus of Chlamydomonas: characterization of forward swimming and alteration of waveform and reversal of motion by calcium ions in vitro

Journal of Cell Science ◽

10.1242/jcs.33.1.235 ◽

1978 ◽

Vol 33 (1) ◽

pp. 235-253 ◽

Cited By ~ 1

Author(s):

J.S. Hyams ◽

G.G. Borisy

Keyword(s):

Calcium Ions ◽

Beat Frequency ◽

Flagellar Apparatus ◽

Adenosine Monophosphate ◽

Adenosine Diphosphate ◽

Living Cells ◽

Exogenous Calcium ◽

Ph Range ◽

Relationship Of

The control of flagellar activity in the biflagellate green alga, Chlamydomonas reinhardtii was investigated by the in vitro reactivation of the isolated flagellar apparatus (the 2 flagella attached to their respective basal bodies plus accessory structures). The waveform and beat frequency of the isolated apparatus in the presence of 1 mM adenosine triphophate (ATP) were comparable to those recorded for living cells. Equimolar concentrations of adenosine diphosphate (ADP) could be substituted for ATP with little change in beat frequency and no apparent change in waveform, suggesting that the latter is converted to ATP by axonemal adenylate kinase. No reactivation occurred in adenosine monophosphate (AMP). But frequencies in cytidine, guanosine and uridine triphosphates (CTP, GTP and UTP) were approximately 10% that obtained in ATP. Reactivation was optimal over a broad pH range between pH 6.4 and pH 8.9 in both APT and ADP. Isolated flagellar apparatus could be induced to change from forward to reverse motion in vitro by manipulation of exogenous calcium ions. The 2 types of motion were directly comparable to recorded responses of living cells. Forward swimming occurred at levels of calcium below 10(−6)M, the isolated apparatus changing to backward motion above this level. Motility was inhibited at concentrations above 10(−3)M. The threshold for reversal of motion by calcium was lowered to 10(−7)M when the flagellar membranes were solubilized with detergent, indicating that the flagellar membranes are involved in the regulaion of the level of calcium within the axoneme. The reversal of motion by calcium was itself freely reversible. The relationship of these observations to the known tactic responses of Chlamydomonas is discussed.

Download Full-text