cicaprost and sulprostone

Prostacyclin analogues have the potential to be effective agents in a new generation of drug-eluting stents by virtue of prostanoid IP receptor mediated anti-proliferative effects on smooth muscle cells. However, prostanoid IP receptor mediated vessel relaxation is reduced at elevated analogue concentrations. The mechanisms underlying this loss of activity are unclear, and its influence on the anti-proliferative potential of these compounds remains to be determined. A classical organ bath approach was used to examine the functional response of the rabbit iliac artery to the prostacyclin analogues, AFP-07 and cicaprost. Selective receptor antagonists for prostanoid IP (RO-1138452), EP(1) (SC-51322) and EP(3) (L-798106) receptors were used to characterise the receptors involved. The effects of these agents on proliferation ([(3)H]-thymidine incorporation) of rabbit iliac artery smooth muscle cells stimulated by foetal calf serum were then studied. AFP-07 gave a bell-shaped log concentration-response curve consisting of prostanoid IP receptor mediated relaxation followed by reversal at higher concentrations. SC-51322 and L-798106 potentiated this relaxation, although only L-798106 completely removed the contractile element. The prostanoid EP(3) receptor agonist, sulprostone, produced constriction, which was attenuated by L-798106. RO-1138452 blocked the inhibitory action of AFP-07 and cicaprost on proliferation, implicating an involvement of prostanoid IP receptors. L-798106 had no effect on the anti-proliferative effect of cicaprost, but reduced the effect of AFP-07. Non-selective activation of prostanoid EP(3) receptors (and possibly prostanoid EP(1) receptors) compromises the relaxant activity of prostacyclin analogues, although it does not reduce the anti-proliferative capacity of these compounds in the model studied.

Topics: Animals; Blood Vessels; Coronary Restenosis; Dinoprostone; Dose-Response Relationship, Drug; Drug-Eluting Stents; Epoprostenol; Iliac Artery; Male; Muscle Contraction; Prostaglandins; Rabbits; Receptors, Epoprostenol

The hyperalgesic response to prostaglandin E2 (PGE2) is thought to be mediated by activation of the cAMP/protein kinase A pathway in primary sensory neurones. The aim of this study was to investigate the relative contribution of different PGE2 (EP) receptor subtypes to the overall activity of adenylyl cyclase in adult rat isolated dorsal root ganglion (DRG) cells, in vitro. PGE2 and the prostanoid EP4 receptor agonist ONO-AE1-329 increased [3H]cAMP production with EC50 values of 500 nM and 70 nM, respectively, and showed similar efficacies. No combination of prostanoid EP1, EP2, EP3 or EP4 receptor selective agonists produced synergistic increases in [3H]cAMP. The prostacyclin mimetic cicaprost increased [3H]cAMP production with an EC50 value of 42 nM and produced a significantly greater maximal response compared with PGE2. No evidence for prostanoid EP3 receptor-dependent inhibition of adenylyl cyclase activity could be obtained to account for the relatively weak effect of PGE2 compared with prostacyclin receptor agonists. Interestingly, sulprostone (prostanoid EP3/EP1 receptor agonist) caused a Rho-kinase-dependent retraction of neurites, suggesting an alternative role for prostanoid EP3 receptors in DRG cells. In conclusion, PGE2 mediated increases in adenylyl cyclase activity in primary sensory neurones is likely to be mediated by activation of prostanoid EP4 receptors, and is not under inhibitory control by prostanoid EP3 receptors.

Topics: Adenylyl Cyclases; Alprostadil; Amides; Animals; Cell Line; Cells, Cultured; Cyclic AMP; Dinoprostone; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Epoprostenol; Ganglia, Spinal; Humans; Intracellular Signaling Peptides and Proteins; Male; Methyl Ethers; Neurites; Prostaglandin D2; Protein Serine-Threonine Kinases; Pyridines; Rats; Rats, Sprague-Dawley; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP2 Subtype; Receptors, Prostaglandin E, EP3 Subtype; Receptors, Prostaglandin E, EP4 Subtype; rho-Associated Kinases; Time Factors; Tritium

We have investigated the actions of various prostanoid receptor agonists on an isolated preparation of the ferret cervical vagus using a grease-gap extracellular recording technique. The potency ranking for depolarization was BW245C (5-(6-carboxyhexyl)-1-(3-cyclohexyl-3-hydroxypropyl) hydantoin; DP-selective, EC50=0.14 microM)>prostaglandin E2 (nonselective EP agonist)>U-46619 (11alpha, 9alpha-epoxymethano-15S-hydroxyprosta-5Z,13E-dienoic acid; TP agonist)>prostaglandin F2alpha (FP receptor agonist). Sulprostone (EP1/EP3-selective), fluprostenol (FP-selective) and cicaprost and iloprost (both IP-selective) had minimal effects. It is likely that DP, EP2/EP4 and TP receptors are present on the vagal fibres of the ferret.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Biguanides; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; Electrophysiology; Epoprostenol; Ferrets; Hydantoins; Iloprost; In Vitro Techniques; Male; Prostaglandins; Prostaglandins F, Synthetic; Serotonin; Vagus Nerve

1. A variety of prostanoids were examined for their ability to alter the periarterial nerve stimulation-induced release of noradrenaline (NA) and neuropeptide Y immunoreactive compounds (NPY-ir) from the perfused mesenteric arterial bed of the rat. 2. Periarterial nerve stimulation (16 Hz) increased the overflow of NA, NPY-ir and perfusion pressure. 3. The prostacyclin (PGI2) analogues, carbaPGI2 and cicaprost both produced a concentration-dependent attenuation of the nerve stimulation-induced increase in NA, NPY-ir overflow and perfusion pressure. 4. The prostaglandin (PG) analogue PGE2 attenuated the evoked increase in NPY-ir overflow as well as a modest decrease in NA. 5. PGE1, sulprostone and iloprost attenuated the nerve stimulation-induced increase in NA overflow but not NPY-ir. 6. Neither PGF2alpha nor the thromboxane A2 analogue U46619 altered the evoked increase in NA or NPY-ir overflow. 7. The results support the view that sympathetic co-transmitter release can be differentially modulated by paracrine/autocrine mediators at sympathetic neuroeffector junctions.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Alprostadil; Animals; Dinoprost; Dinoprostone; Electric Stimulation; Epoprostenol; Iloprost; Male; Mesenteric Arteries; Neuropeptide Y; Norepinephrine; Perfusion; Prostaglandins; Radioimmunoassay; Rats; Rats, Sprague-Dawley

1. Primary cultures of adult rat dorsal root ganglia (DRG) were prepared to examine the properties of prostacyclin (IP) receptors and prostaglandin E(2) (EP) receptors in sensory neurones. 2. IP receptor agonists, cicaprost and iloprost, stimulated adenylyl cyclase activity with EC(50) values of 22 and 28 nM, respectively. Prostaglandin E(1) (PGE(1)) and prostaglandin E(2) (PGE(2)) were 7 fold less potent than cicaprost and iloprost, with PGE(2) displaying a lower maximal response. 3. Adenylyl cyclase activation by iloprost, PGE(1) and PGE(2), but not by forskolin, was highly dependent on DRG cell density. Although the potency of iloprost and PGE(2) for stimulating adenylyl cyclase was unchanged, their maximal responses were significantly increased at low cell density. 4. Both IP and EP(2/4) receptors could be down-regulated by agonist pretreatment, however the presence of cyclo-oxygenase (COX) inhibitors did not prevent this apparent down-regulation of IP and EP(2/4) receptors at high DRG cell densities. 5. Stimulation of adenylyl cyclase by the neuropeptide calcitonin gene-related peptide was also decreased at high DRG cell density, whereas the responses to beta-adrenoceptor agonists were increased at high DRG cell density. 6. Addition of nerve growth factor (NGF), or the addition of anti-neurotrophin antibodies during the 5-day culture of DRG cells, had no effect on IP receptor-mediated responses. 7. These results indicate that G(s)-coupled receptors involved in nociception are regulated in a variable manner in adult rat sensory neurones, and that this cell density-dependent regulation may be agonist-independent for IP and EP(2/4) receptors.

Topics: Adenylyl Cyclases; Aging; Alprostadil; Animals; Antineoplastic Agents; Cell Count; Cells, Cultured; Colforsin; Cyclic AMP; Cyclooxygenase Inhibitors; Dinoprostone; Down-Regulation; Enzyme Activation; Epoprostenol; Ganglia, Spinal; Iloprost; Male; Neurons, Afferent; Rats; Rats, Sprague-Dawley; Receptors, Epoprostenol; Receptors, Prostaglandin

The effects of various prostanoids on the growth, melanogenesis and dendrification of cultured iridal melanocytes were studied. Iridal melanocytes were isolated and cultured with medium supplemented with cAMP elevating agents and basic fibroblast growth factor (bFGF) (complete medium). The iridal melanocytes were plated into multiple well plates and cultured with complete medium or various deleted media with or without various prostanoids at different concentrations. After 6 days, the numbers of cells and dendrites were counted and melanin content was measured and compared with controls. Prostaglandin E(2), an EP(2)receptor agonist (AH 13205) and AGN 192093 (thromboxane mimetic) stimulated growth, melanogenesis and dendrification of cultured iridal melanocytes in cAMP-deleted medium. A mixed EP(1)and EP(3)receptor agonist (sulprostone), a EP(4)receptor agonist (ONO-AE1-329), IP receptor agonists (cicaprost or iloprost) and a TP receptor agonist (U-46619) showed no effect. Prostaglandin D(2)showed stimulating effects. However, these stimulating effects could not be blocked by the addition of a DP receptor antagonist (BW A868C). Furthermore, a DP receptor agonist (BW 245C) showed no effects, indicating that the effect of prostaglandin D(2)may involve receptors other than the DP receptor subtype. The present study indicates that: (1) among various EP receptor agonists, only an EP(2)receptor agonist has stimulating effects on iridal melanocytes; (2) DP, IP and TP receptor agonists do not have stimulating effects; and (3) the mechanisms of action of prostaglandin D(2)and AGN 192093 need further study.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Adult; Cell Count; Cells, Cultured; Cyclic AMP; Dinoprostone; Epoprostenol; Fibroblast Growth Factor 2; Humans; Hydantoins; Iris; Melanins; Melanocytes; Prostaglandin Antagonists; Prostanoic Acids; Receptors, Prostaglandin

1. Our study shows that the prostacyclin analogues AFP-07 and cicaprost are moderately potent agonists for prostanoid EP(4) receptors, in addition to being highly potent IP(1) receptor agonists. Both activities were demonstrated on piglet and rabbit saphenous veins, which are established EP(4) preparations. 2. On piglet saphenous vein, PGE(2) was 6.1, 24, 96, 138, 168 and 285 times respectively more potent than AFP-07, cicaprost, PGI(2), iloprost, carbacyclin and TEI-9063 in causing relaxation. Another prostacyclin analogue taprostene did not induce maximum relaxation (21 - 74%), and did not oppose the action of PGE(2). The EP(4) receptor antagonist AH 23848 (30 microM) blocked relaxant responses to PGE(2) (dose ratio=8.6+/-1.3, s.e.mean) to a greater extent than cicaprost (4.9+/-0.7) and AFP-07 (3.8+/-0.8), had variable effects on TEI-9063-induced relaxation (3.7+/-1.5), and had no effect on taprostene responses (<2.0). 3. On rabbit saphenous vein, AH 23848 blocked the relaxant actions of PGE(2), AFP-07, cicaprost, iloprost and carbacyclin to similar extents. 4. AFP-07, cicaprost and TEI-9063 showed high IP(1) relaxant potency on piglet carotid artery, rabbit mesenteric artery and guinea-pig aorta, with AFP-07 confirmed as the most potent IP(1) agonist reported to date. AH 23848 did not block cicaprost-induced relaxation of piglet carotid artery. EP(3) contractile systems in these preparations can confound IP(1) agonist potency estimations. 5. Caution is urged when using AFP-07 and cicaprost to characterize IP(1) receptors in the presence of EP(4) receptors. Taprostene may be a lead to a highly selective IP(1) receptor agonist.

Topics: Alprostadil; Animals; Biphenyl Compounds; Blood Vessels; Carotid Arteries; Dinoprostone; Dose-Response Relationship, Drug; Endothelium, Vascular; Epoprostenol; Guinea Pigs; In Vitro Techniques; Male; Mesenteric Arteries; Mice; Rabbits; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP4 Subtype; Saphenous Vein; Swine; Vasoconstriction; Vasodilation

1. The influence of endogenously produced prostanoids on active transepithelial Ca2+ transport and cAMP formation was investigated in immunodissected rabbit kidney connecting and cortical collecting tubule cells grown to confluency on permeable supports. 2. The cyclo-oxygenase inhibitor indomethacin dose-dependently (IC50 = 18 nM) reduced the net apical-to-basolateral Ca2+ transport by 57%. Inhibition was reversed in medium obtained from monolayers incubated in the absence of indomethacin. 3. HPLC analysis following incubation with 14C-labelled arachidonic acid revealed the presence of a wide variety of radiolabelled prostanoids in both the apical and basolateral media. These findings are compatible with the endogenous production and subsequent release of stimulatory prostanoids. 4. The inhibitory action of indomethacin was reversed by the addition of the prostanoids PGE1, PGE2 and PGA2, but not PGD2, PGF2 alpha, the stable PGI2 analogue cicaprost or the thromboxane A2 mimetic U-46619. PGE2 stimulated transepithelial Ca2+ transport dose dependently (EC50 = 3 nM), irrespective of the compartment of which it was added. The stimulatory effect of PGE2 was paralleled by increased cAMP formation, suggesting the apical and basolateral presence of stimulatory prostanoid receptors EP2 and/or EP4. 5. Sulprostone, an analogue selective for EP1 and EP3 receptors, inhibited transepithelial Ca2+ transport in indomethacin-treated monolayers only when applied basolaterally, suggesting the exclusive presence of inhibitory EP receptors on the basolateral membrane. 6. The percentage by which parathyroid hormone and arginine vasopressin increased both transepithelial Ca2+ transport and cAMP formation was dramatically increased in indomethacin-inhibited cells as compared with control cells, demonstrating that indomethacin unmasks the actions of these hormones to their full extent.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Arachidonic Acid; Arginine Vasopressin; Biological Transport; Calcium; Cells, Cultured; Chromatography, High Pressure Liquid; Cyclic AMP; Cyclooxygenase Inhibitors; Dinoprostone; Eicosanoids; Epoprostenol; Indomethacin; Kidney Tubules; Models, Biological; Parathyroid Hormone; Prostaglandin Endoperoxides, Synthetic; Prostaglandins; Rabbits; Receptors, Prostaglandin; Thromboxane A2; Virulence Factors, Bordetella

[3H]PGE2 and [3H]PGF2 alpha were shown to bind with similar binding capacity and dissociation constants to bovine aorta endothelial cells. The similarity in the binding parameters suggests that both agonists may bind to the same binding site. Displacement of [3H]PGE2 performed with PGE2, PGF2 alpha or U-46619, a thromboxane agonist, shows that all three prostanoids displaced the bound [3H]PGE2 with comparable potency (IC50 = 10(-7) M). These results indicated that the three different prostanoids, which serve as specific agonists to different prostanoid receptors, also compete for the same binding site in bovine endothelial cells with similar affinity. Comparison of the displacement of [3H]PGE2 or [3H]PGF2 alpha by a number of prostaglandin agonists and antagonists further supports the notion that the natural prostanoids bind with similar affinities to the same binding site. Thus, sulprostone, an EP1/EP3 agonist, displaced bound [3H]PGE2 and [3H]PGF2 alpha with IC50 of about 10(-7) M. On the other hand, thromboxane antagonists (BAY u-3405 and GR-32191B), EP1 specific antagonist (SC-19220) EP1/DP antagonist (AH-6809) and iloprost, a stable prostacyclin agonist, failed to displace bound [3H]PGE2 or [3H]PGF2 alpha at a concentration range of 10(-9)-10(-6) M. Gradual increase of sodium fluoride (NaF), a general activator of G binding proteins, or incubation of permeabilized cells with GTP gamma S resulted in a decrease in [3H]PGE2 binding, suggesting that the binding site represents a low-affinity common prostanoid receptor which, similar to other prostanoid receptors, is probably coupled with G binding proteins.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Aorta; Binding Sites; Biphenyl Compounds; Carbazoles; Cattle; Cells, Cultured; Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; Dinoprostone; Endothelium, Vascular; Epoprostenol; Heptanoic Acids; Iloprost; Prostaglandin Endoperoxides, Synthetic; Prostaglandins; Sulfonamides; Thromboxane A2; Thromboxanes; Xanthenes; Xanthones

The group of prostaglandin (PG) E2- and prostacyclin receptors consists of different subtypes, which exhibit different affinities for prostaglandins and synthetic analogues. PGE2 activities the E-type PG receptor subtypes EP1, EP2 and EP3, whereas the PGE2 analogue, sulprostone, binds only to the EP1 and EP3 receptor subtypes. The stable PGI2 analogues, iloprost and cicaprost, both activate the PGI2 receptor (IP) and iloprost, additionally, bind to the EP1 subtype. Using these subtype-selective PG receptor agonists, we studied the interaction of PG receptor subtypes with Gs and Gi-type heterotrimeric guanine nucleotide-binding proteins (G proteins) in membranes from the human erythroleukaemia cell line, HEL. Sulprostone stimulated high-affinity GTPase in HEL membranes in a pertussis toxin (PTX)-sensitive manner. In contrast, the stimulations induced by PGE2, iloprost and cicaprost were only partially inhibited by PTX. PGE2, sulprostone, iloprost and cicaprost stimulated cholera toxin-catalysed ADP-ribosylation as well as labelling with GTP azidoanilide of membrane proteins comigrating with immunologically identified Gi protein alpha subunits. Furthermore, PGE2, iloprost and cicaprost enhanced GTP azidoanilide-labelling of Gs protein alpha subunits, whereas sulprostone did not. We suggest that in HEL cells (1) EP1 and EP3 receptor subtypes activate G1 proteins, that (2) the EP2 receptor subtype activates Gs proteins and that (3) the IP receptor activates both Gi and Gs proteins.

Topics: Cell Membrane; Dinoprostone; Epoprostenol; GTP-Binding Proteins; Humans; Iloprost; Leukemia, Erythroblastic, Acute; Prostaglandins E; Receptors, Epoprostenol; Receptors, Prostaglandin; Receptors, Prostaglandin E; Signal Transduction; Tumor Cells, Cultured

The initial, fast phase of contraction of the guinea-pig vas deferens produced by electrical field stimulation (10 pulses) was dose-dependently and completely inhibited by prostaglandin (PG) E2, sulprostone and, at high concentrations, by cicaprost. Sulprostone was more potent than PGE2 indicating that the EP3 receptor was involved. Cicaprost (a PGI2 analogue) apparently had weak EP3 receptor against activity. At low concentrations, cicaprost potentiated the contractions of the vas deferens, presumably by acting on an IP receptor. Exogenous arachidonic acid also dose-dependently and completely inhibited contractions of the guinea-pig vas deferens. The action of arachidonic acid was delayed when compared to PGE2 and was inhibited by indomethacin, suggesting that the arachidonic acid was converted to PGE2 by the vas deferens. Indomethacin (1.4 to 6.0 microM) had no significant, potentiating effect on the contractions of the guinea-pig vas deferens which suggests that endogenous PGs do not normally inhibit this fast phase of contraction. In higher concentrations, the contractions were reduced by indomethacin. The fast phase of concentration of the guinea-pig vas deferens consisted of 3 components. PGE2, sulprostone and arachidonic acid inhibited all components. The order of inhibition of the components was component 2, then component 3, followed by component 1.

Topics: Animals; Arachidonic Acid; Dinoprostone; Electric Stimulation; Epoprostenol; Guinea Pigs; In Vitro Techniques; Indomethacin; Male; Muscle Contraction; Prostaglandins; Prostaglandins, Synthetic; Sympathetic Nervous System; Synaptic Transmission; Vas Deferens

We have investigated the ability of three synthetic prostanoids to directly influence uterine contractility by studying the effects in vitro. Strips of lower uterine segment smooth muscle were obtained from women undergoing elective cesarean section at term. The ability of these strips to develop tension in the presence of cumulative additions of prostanoids or oxytocin was assessed. Spontaneous contractions were inhibited by ZK 96.480, a stable synthetic analog of prostaglandin I2, with a 50th percentile effective concentration (EC50) of 8 nmol/L. Both sulprostone, an analog with selectivity for some of the actions of prostaglandin E2, and U-44069, a stable thromboxane A2 mimetic, caused excitation with EC50s of 20 and 16 nmol/L, respectively. The EC50 for oxytocin was 6 nmol/L. There were no significant differences in the maximal tensions developed in response to the excitatory prostanoids or oxytocin.

Topics: Dinoprostone; Dose-Response Relationship, Drug; Epoprostenol; Female; Humans; In Vitro Techniques; Myometrium; Oxytocin; Prostaglandin Endoperoxides, Synthetic; Prostaglandins E, Synthetic; Prostaglandins, Synthetic; Uterine Contraction