iloprost and fluprostenol

Prostanoid-modulatory approaches in heart failure patients have displayed effects which may seem to be mutually incompatible. Both treatment with prostanoids and inhibition of prostanoid synthesis have resulted in increased mortality in heart failure patients. Currently, it is unknown if prostanoids mediate contractile effects in failing human heart and if this can explain some of the clinical effects seen after prostanoid modulatory treatments. Therefore, the objectives of this study were to determine if prostanoids could elicit direct inotropic responses in human ventricle, and if so to determine if they are modified in failing ventricle. Contractile force was measured in left ventricular strips from non-failing or failing human and rat hearts. The ratio of phosphorylated to non-phosphorylated myosin light chain 2 (MLC-2) was measured by Western blotting in myocardial strips, and the levels of prostanoid FP receptor mRNA and protein were measured in rat by real-time RT-PCR and receptor binding assays. In non-failing human hearts, prostanoids evoked a positive inotropic effect and an increase of MLC-2 phosphorylation which was absent in failing human hearts. In failing rat heart, the prostanoid FP receptor-mediated inotropic response and prostanoid FP receptor-density was reduced by ~40-50% compared to non-failing rat heart. Prostanoids mediate a sustained positive inotropic response in non-failing heart, which appears to be down regulated in failing heart. The pathophysiological significance of changes in prostanoid-mediated inotropic support in the failing heart remains to be determined.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alprostadil; Animals; Cardiac Myosins; Child; Disease Models, Animal; Female; Heart Failure; Heart Ventricles; Humans; Iloprost; Male; Middle Aged; Myocardial Contraction; Myosin Light Chains; Prostaglandins F, Synthetic; Rats; Receptors, Prostaglandin; Ventricular Function

Although prostanoids are known to be involved in regulation of the spontaneous beating rate of cultured neonatal rat cardiomyocytes, the various subtypes of prostanoid receptors have not been investigated in detail. In our experiments, prostaglandin (PG)F(2α) and prostanoid FP receptor agonists (fluprostenol, latanoprost and cloprostenol) produced a decrease in the beating rate. Two prostanoid IP receptor agonists (iloprost and beraprost) induced first a marked drop in the beating rate and then definitive abrogation of beating. In contrast, the prostanoid DP receptor agonists (PGD(2) and BW245C) and TP receptor agonists (U-46619) produced increases in the beating rate. Sulprostone (a prostanoid EP(1) and EP(3) receptor agonist) induced marked increases in the beating rate, which were suppressed by SC-19220 (a selective prostanoid EP(1) antagonist). Butaprost (a selective prostanoid EP(2) receptor agonist), misoprostol (a prostanoid EP(2) and EP(3) receptor agonist), 11-deoxy-PGE(1) (a prostanoid EP(2), EP(3) and EP(4) receptor agonist) did not alter the beating rate. Our results strongly suggest that prostanoid EP(1) receptors are involved in positive regulation of the beating rate. Prostanoid EP(1) receptor expression was confirmed by western blotting with a selective antibody. Hence, neonatal rat cardiomyocytes express both prostanoid IP and FP receptors (which negatively regulate the spontaneous beating rate) and prostanoid TP, DP(1) and EP(1) receptors (which positively regulate the spontaneous beating rate).

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Animals, Newborn; Blotting, Western; Cells, Cultured; Cloprostenol; Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; Dinoprostone; Dose-Response Relationship, Drug; Epoprostenol; Hydantoins; Iloprost; Latanoprost; Myocytes, Cardiac; Prostaglandin D2; Prostaglandins F, Synthetic; Rats; Rats, Sprague-Dawley; Receptors, Prostaglandin; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Thromboxane

The pharmacological properties of [(3)H]-prostaglandin E(2) ([(3)H]-PGE(2)) binding to washed homogenates of hamster uterus were determined. Scatchard analysis of competition data yielded dissociation constants (K(d)s) of 30.9 +/- 5.6 nM (n = 3) and apparent receptor density (B(max)) of 25.25 +/- 1.89 pmol g(-1) wet weight tissue (74 +/- 8% specific binding). Competition studies yielded the following affinity parameters (K(i)) for various prostanoids: GR63799X = 13 4 nM; PGE(2) = 17 +/- 3 nM; sulprostone = 64 +/- 5 nM; enprostil = 67 +/- 3 nM; misoprostol = 124 +/- 15 nM; cloprostenol = 187 +/- 33 nM; carba-prostacyclin = 260 +/- 167 nM; iloprost = 555 +/- 162 nM; PGF(2 alpha) = 767 +/- 73 nM; PGD(2) > 3560 nM; fluprostenol = 11 790 +/- 2776 nM; RS93520 = 21 558 +/- 14 228 nM. These data closely matched the pharmacological profile of previously described EP(3) receptors such as in bovine corpus luteum (BCLM) and the cloned mammalian EP(3) receptors. The high correlation between the current hamster uterus pharmacology data vs the EP(3) receptor binding in BCLM (r = 0.94; P < 0.0001), vs cloned human EP(3) receptor (r = 0.94, P < 0.0001), vs the cloned mouse EP(3) receptor binding (r = 0.78; P < 0.002), vs cloned rat EP(3) receptor (r = 0.9, P < 0.0004), and vs EP(3) receptor-mediated functional responses (r = 0.72, P < 0.02) substantiated the conclusion that the hamster uterus contains EP(3) receptor binding sites.

Topics: Animals; Binding Sites; Biphenyl Compounds; Bridged Bicyclo Compounds, Heterocyclic; Cattle; Cloprostenol; Cricetinae; Dinoprost; Dinoprostone; Enprostil; Epoprostenol; Fatty Acids, Unsaturated; Female; Hydantoins; Hydrazines; Iloprost; Latanoprost; Misoprostol; Prostaglandins; Prostaglandins E, Synthetic; Prostaglandins F, Synthetic; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP3 Subtype; Tritium; Uterus

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

The role of prostaglandins (PGs) in embryo hatching remains controversial. In addition, there is no direct evidence that mouse embryos synthesize PGs.. The effects of endogenous PG on mouse embryo hatching were evaluated by blocking endogenous PG synthesis with indomethacin. Specific cyclooxygenase (COX) inhibitors were used to identify the role of COX-1- and COX-2-derived PGs. An eicosanoid profile was generated by incubating blastocysts with [3H]arachidonic acid and analysing the metabolites by high performance liquid chromatography. The expression and the localization of COX-1, COX-2 and prostacyclin synthase (PGIS) were examined by western blot analysis and immunohistochemistry.. The hatching of embryos cultured in 30 microl of protein-free medium was blocked by indomethacin (P = 0.007) or a selective COX-2 inhibitor (P = 0.004). Adding back iloprost, a prostacyclin analogue, abolished the effects of the COX-2 inhibitor. Prostacyclin was the most abundant PG produced by mouse blastocysts, which expressed COX-1, COX-2 and PGIS. COX-1, COX-2 and PGIS were expressed in 4-cell stage embryos and beyond; they were present in the inner cell mass and the trophectoderm of the blastocysts.. Mouse embryos express COX-1, COX-2 and PGIS which catalyse the formation of PGI2; COX-2-derived PGI2 plays a critical role in embryo hatching.

Topics: Animals; Arachidonic Acid; Blastocyst; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Cytochrome P-450 Enzyme System; Dinoprostone; Embryo Culture Techniques; Embryo, Mammalian; Epoprostenol; Female; Iloprost; Indomethacin; Intramolecular Oxidoreductases; Male; Membrane Proteins; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Pregnancy; Prostaglandin-Endoperoxide Synthases; Prostaglandins F, Synthetic; Pyrazoles

1. To characterize the prostanoid receptors (TP, FP, EP(1) and/or EP(3)) involved in the vasoconstriction of human pulmonary veins, isolated venous preparations were challenged with different prostanoid-receptor agonists in the absence or presence of selective antagonists. 2. The stable thromboxane A(2) mimetic, U46619, was a potent constrictor agonist on human pulmonary veins (pEC(50)=8.60+/-0.11 and E(max)=4.61+/-0.46 g; n=15). The affinity values for two selective TP-antagonists (BAY u3405 and GR32191B) versus U46619 were BAY u3405: pA(2)=8.94+/-0.23 (n=3) and GR32191B: apparent pK(B)=8.25+/-0.34 (n=3), respectively. These results are consistent with the involvement of TP-receptor in the U46619 induced contractions. 3. The two EP(1)-/EP(3)- agonists (17-phenyl-PGE(2) and sulprostone) induced contraction of human pumonary veins (pEC(50)=8.56+/-0.18; E(max)=0.56+/-0.24 g; n=5 and pEC(50)=7.65+/-0.13; E(max)=1.10+/-0.12 g; n=14, respectively). The potency ranking for these agonists: 17-phenyl-PGE(2) > sulprostone suggests the involvement of an EP(1)-receptor rather than EP(3). In addition, the contractions induced by sulprostone, 17-phenyl-PGE(2) and the IP-/EP(1)- agonist (iloprost) were blocked by the DP-/EP(1)-/EP(2)-receptor antagonist (AH6809) as well as by the EP(1) antagonist (SC19220). 4. PGF(2alpha) induced small contractions which were blocked by AH6809 while fluprostenol was ineffective. These results indicate that FP-receptors are not implicated in the contraction of human pulmonary veins. 5. These data suggest that the contractions induced by prostanoids involved TP- and EP(1)-receptors in human pulmonary venous smooth muscle.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Biphenyl Compounds; Carbazoles; Culture Techniques; Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; Dinoprostone; Dose-Response Relationship, Drug; Endothelium, Vascular; Female; Heptanoic Acids; Humans; Iloprost; Male; Middle Aged; Muscle Contraction; Muscle, Smooth, Vascular; Prostaglandin Antagonists; Prostaglandins F, Synthetic; Pulmonary Veins; Receptors, Prostaglandin; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP3 Subtype; Receptors, Thromboxane; Sulfonamides; Vasoconstriction; Xanthenes; Xanthones

The agonist activities of a range of prostaglandin analogues on smooth muscle preparations sensitive to prostaglandin E2 (PGE2) have been investigated. When necessary thromboxane-like activity was eliminated using the thromboxane receptor antagonists EP 045 and EP 092. On the bullock iris sphincter, rat stomach fundus and guinea-pig trachea, (+/-) omega-tetranor-16-p-chlorophenoxy PGE2 (ICI 80205) and 16,16-dimethyl PGE2 were more active contractile agents than PGE2, whereas for relaxant activity on the cat trachea, guinea-pig trachea and dog hind limb arterial vessels in vivo the order of potency was reversed. 11-Deoxy PGE1 exhibited greater relaxant than contractile activity when compared to PGE2. Iloprost and 6a-carba-delta 6,6aPGI1 (potent mimetics of PGI2) showed high contractile activity on the PGE-sensitive preparations. PGI2 was less active and another potent PGI2 mimetic, ZK 96480, showed only very weak activity. When tested, the dibenzoxazepines SC 19220 and SC 25191 blocked the contractile actions of iloprost and 6a-carba-delta 6,6aPGI1 and those of PGE2 and 16,16-dimethyl PGE2 to similar extents. Each of the PGI2 analogues showed weak activity on the relaxant systems. On the proximal portion of the ascending colon of the rat, PGI2, iloprost, 6a-carba-delta 6,6aPGI1 and ZK 96480 always inhibited spontaneous activity at nanomolar concentrations. PGE2 and PGE1 showed weak contractile activity. The distal portion of the ascending colon was more responsive to the contractile action of PGE analogues: both iloprost and 6a-carba-delta 6,6aPGI1 showed evidence of contractile activity, whereas PGI2 and ZK 96480 always inhibited spontaneous activity. Evidence was obtained that the rat stomach fundus also contains a PGF receptor; (+/-) omega-tetranor-16-m-trifluoromethylphenoxy PGF2 alpha (ICI 81008) acted as a specific agonist. PGF2 alpha and its omega-tetranor-16-p-fluorophenoxy analogue produced a higher maximum response that ICI 81008 probably due to their additional agonist action at the PGE receptor. The data support the hypothesis that there are two subtypes of the PGE receptor. ZK 96480 has minimal activity on both receptor subtypes and appears to be a highly specific PGI2 mimetic.

Topics: Animals; Cats; Colon; Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; Dogs; Dose-Response Relationship, Drug; Epoprostenol; Female; Gastric Fundus; Guinea Pigs; Hindlimb; Iloprost; In Vitro Techniques; Iris; Male; Muscle Contraction; Muscle, Smooth; Prostaglandins E; Prostaglandins F; Prostaglandins F, Synthetic; Prostaglandins, Synthetic; Rats; Receptors, Cell Surface; Receptors, Prostaglandin; Trachea