prostaglandin-d2 and sulprostone

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 cyclooxygenase-prostanoid pathway regulates myometrial contractility through activation of prostanoid receptors on uterine smooth muscles. However, the possible expression of prostanoid receptors on autonomic nerves cannot be excluded completely. The aim of the present study was to clarify the presence of neural prostanoid receptors on adrenergic nerves in the porcine uterine longitudinal muscle. In [(3)H]-noradrenaline-loaded longitudinal muscle strips of porcine uterus, electrical field stimulation (EFS) evoked [(3)H]-noradrenaline release in a stimulation frequency-dependent manner. The EFS-evoked release was completely abolished in Ca(2+)-free (EGTA, 1mM) incubation medium and by tetrodotoxin or omega-conotoxin GVIA, suggesting that [(3)H]-noradrenaline was released from neural components. The EFS-evoked [(3)H]-noradrenaline release was significantly enhanced by treatment with indomethacin. In the presence of indomethacin, PGE(2) and PGF(2alpha), but not PGD(2), inhibited the EFS-evoked [(3)H]-noradrenaline release. Of synthetic prostanoid receptor agonists examined, both U46619 (TP) and sulprostone (EP(1)/EP(3)) decreased the EFS-evoked [(3)H]-noradrenaline release in a concentration-dependent manner, while fluprostenol (FP), BW245C (DP) and butaprost (EP(2)) were almost ineffective. SQ29548 (TP receptor antagonist) blocked the effect of U46619, but SC19220 (EP(1) receptor antagonist) did not change the inhibition by sulprostone or PGE(2). Double immunofluorescence staining using protein gene product 9.5, tyrosine hydroxylase, EP(3) receptor and TP receptor antibodies suggested the localization of EP(3) or TP receptors on adrenergic nerves in the porcine uterus. These results indicated that neural EP(3) and TP receptors are present on adrenergic nerves of the porcine uterine longitudinal muscle. Endogenous prostanoid produced by cyclooxygenase can regulate noradrenaline release in an inhibitory manner through activation of these neural prostanoid receptors.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Alprostadil; Animals; Dinoprost; Dinoprostone; Electric Stimulation; Female; In Vitro Techniques; Microscopy, Confocal; Microscopy, Fluorescence; Myometrium; Neurons; Norepinephrine; Prostaglandin D2; Prostaglandins; Prostaglandins F, Synthetic; Receptors, Androgen; Receptors, Prostaglandin; Swine

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

The role of prostaglandins in mechanical scratching-induced cutaneous barrier disruption in mice was investigated. Skin prostaglandins contents were measured after cutaneous barrier function was disrupted by scratching using a stainless-steal wire brush (mechanical scratching), then effects of prostanoids on recovery of cutaneous barrier functions were examined. This mechanical scratching increased transepidermal water loss and skin prostaglandins (prostaglandin D2, prostaglandin E2, 6-keto-prostaglandin F1alpha and prostaglandin F2alpha) contents, count-dependently. Topical application of indomethacin immediately after cutaneous barrier disruption delayed the recovery period of cutaneous barrier disruption. We examined effects of several prostanoids (prostaglandin D2, prostaglandin E2, prostaglandin F2alpha, prostaglandin I2 and U46619) on delay of the recovery process of mechanical scratching-induced cutaneous barrier disruption with treatment of indomethacin. Topically applied prostaglandin D2 and prostaglandin E2 accelerated the recovery of cutaneous barrier disruption and topical application of prostaglandin J2, limaprost, sulprostone and ONO-4819, but not 13,14-dihydro-15-keto-prostaglandin D2, 15-deoxy-Delta(12,14)-prostaglandin J2, 17-phenyl-trinor-prostaglandin E2 or butaprost had effects on recovery of the cutaneous barrier. These results suggest that prostaglandin D2 and prostaglandin E2 accelerate the recovery process of cutaneous barrier disruption caused by mechanical scratching, via specific prostanoid DP1, EP3 and EP4 receptors.

Topics: 6-Ketoprostaglandin F1 alpha; Alprostadil; Animals; Anti-Inflammatory Agents, Non-Steroidal; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; Heptanoates; Indomethacin; Male; Mice; Mice, Inbred BALB C; Prostaglandin D2; Pruritus; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP4 Subtype; Skin; Stress, Mechanical; Time Factors; Water Loss, Insensible

1. Since the role of prostanoid receptors in intestinal peristalsis is largely unknown, the peristaltic motor effects of some prostaglandin (DP, EP, IP), thromboxane (TP) and leukotriene (LT) receptor agonists and antagonists were investigated. 2. Propulsive peristalsis in fluid-perfused segments from the guinea-pig small intestine was triggered by a rise of the intraluminal pressure and recorded via the intraluminal pressure changes associated with the peristaltic waves. Alterations of distension sensitivity were deduced from alterations of the peristaltic pressure threshold and modifications of peristaltic performance were reflected by modifications of the amplitude, maximal acceleration and residual baseline pressure of the peristaltic waves. 3. Four categories of peristaltic motor effects became apparent: a decrease in distension sensitivity and peristaltic performance as induced by the EP1/EP3 receptor agonist sulprostone and the TP receptor agonist U-46619 (1-1000 nM); a decrease in distension sensitivity without a major change in peristaltic performance as induced by PGD(2) (3-300 nM) and LTD(4) (10-100 nM); a decrease in peristaltic performance without a major change in distension sensitivity as induced by PGE(1), PGE(2) (1-1000 nM) and the EP1/IP receptor agonist iloprost (1-100 nM); and a decrease in peristaltic performance associated with an increase in distension sensitivity as induced by the EP2 receptor agonist butaprost (1-1000 nM). The DP receptor agonist BW-245 C (1-1000 nM) was without effect. 4. The peristaltic motor action of sulprostone remained unchanged by the EP1 receptor antagonist SC-51089 (1 micro M) and the DP/EP1/EP2 receptor antagonist AH-6809 (30 micro M), whereas that of U-46619 and LTD(4) was prevented by the TP receptor antagonist SQ-29548 (10 micro M) and the cysteinyl-leukotriene(1) (cysLT(1)) receptor antagonist tomelukast (10 micro M), respectively. 5. These observations and their pharmacological analysis indicate that activation of EP2, EP3, IP, TP and cysLT(1) receptors, but not DP receptors, modulate intestinal peristalsis in a receptor-selective manner, whereas activation of EP1 seems to be without influence on propulsive peristalsis. In a wider perspective it appears as if the effect of prostanoid receptor agonists to induce diarrhoea is due to their prosecretory but not peristaltic motor action.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Alprostadil; Animals; Bridged Bicyclo Compounds, Heterocyclic; Dinoprostone; Dose-Response Relationship, Drug; Fatty Acids, Unsaturated; Female; Guinea Pigs; Hydantoins; Hydrazines; Iloprost; In Vitro Techniques; Intestine, Small; Leukotriene Antagonists; Leukotriene D4; Male; Oxazepines; Peristalsis; Prostaglandin D2; Prostaglandins A; Receptors, Leukotriene; Receptors, Prostaglandin; Xanthenes; Xanthones; Yohimbine

Prostaglandins (PGs) have been implicated in the regulation of vasopressin (VP) and oxytocin (OT) release in response to various stimuli. To examine the site and mechanism of actions of PGs, we studied effects of PGE2 and PG-receptor agonists on supraoptic nucleus (SON) neurones of rat hypothalamic slice preparations using extracellular recording and whole-cell patch-clamp techniques. PGE2 modulated the electrical activity of more than 80% of the neurones studied. The effects of PGE2 on both phasic and non-phasic neurones were mostly excitatory, and dose-dependent. The effects of PGE2 were mimicked by PGF2alpha or the FP agonist, fluprostenol, whereas PGD2 or the selective EP, IP or TP agonist was less effective or had no effect. The effects of PGE2 were unaffected by the EP1 antagonist, SC-51322, but reduced to 80% of control by the EP1/FP/TP antagonist, ONO-NT-012, which reduced the effects of fluprostenol to 32% of control. Moreover, some neurones responsive to PGE2 did not respond to fluprostenol. Patch-clamp analysis in SON slice preparations revealed that PGE2 at 10(-6) M depolarized the membrane potential by 3.9+/-0.3 mV from the resting membrane potential of -58.4+/-2.2 mV in the current-clamp mode. In the voltage-clamp mode, PGE2 induced inward currents at a holding potential of -70 or -80 mV, while it did not affect spontaneous excitatory postsynaptic currents. PGE2 induced currents also in dissociated SON neurones and the reversal potential of the currents was -35.5+/-0.9 mV, which was similar to that of currents induced by fluprostenol. These results suggest that SON neurones possess at least two types of PG receptors, FP receptors and EP receptors of a subclass different from EP1, EP2, or EP3, and that activation of these receptors leads to the opening of nonselective cation channels, membrane depolarization and increase of the action potential discharge.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Bridged Bicyclo Compounds; Dinoprost; Dinoprostone; Dose-Response Relationship, Drug; Excitatory Postsynaptic Potentials; In Vitro Techniques; Male; Neurons; Oxazepines; Patch-Clamp Techniques; Prostaglandin D2; Prostaglandins, Synthetic; Rats; Rats, Wistar; Receptors, Prostaglandin; Styrenes; Supraoptic Nucleus

The structure-activity relations and signal transduction pathways for the anabolic effects of prostaglandins were examined in cultured fetal rat calvariae. In the presence of cortisol prostaglandins of the E and F series (10(-9) to 10(-5) M) produced a dose-related increase in [3H]thymidine incorporation up to 4-fold at 24 h. Prostaglandin E2 (PGE2) was also effective in the absence of cortisol. Butaprost (10(-6) M), a selective EP-2 receptor agonist, produced partial stimulation. Prostaglandin D2, prostacyclin, sulprostone, an EP-1 and EP-3 receptor agonist, and fluprostenol, an FP receptor agonist, were ineffective. Forskolin (10(-4) M) increased [3H]thymidine incorporation 3-fold, while phorbol myristate acetate (PMA) (10(-6) M) produced a 1.8-fold increase. Isobutylmethylxanthine (IBMX) increased [3H]thymidine incorporation in control cultures, in the absence of cortisol, and increased the response to PGE2 in control and cortisol-treated cultures. [3H]proline incorporation into collagen and noncollagen protein was measured in the continuous presence of prostaglandins and cortisol for 72-96 h (continuous model) or when prostaglandins and cortisol were applied for 24 h, followed by culture for 48 h in control medium (on/off model). The effects on collagen were greater than on noncollagen proteins, so that the percent of collagen synthesis increased. The effects of prostaglandins and forskolin paralleled their mitogenic effects. PMA increased only noncollagen protein. Indomethacin did not diminish the anabolic response, while aphidicolin produced only partial inhibition. We conclude that the anabolic effects of prostaglandins on replication and differentiation of osteoblasts are likely to be mediated by an EP-2 receptor that stimulates adenylate cyclase.

Topics: 1-Methyl-3-isobutylxanthine; Abortifacient Agents, Nonsteroidal; Alprostadil; Animals; Cell Differentiation; Collagen; Dinoprostone; Dose-Response Relationship, Drug; Drug Synergism; Epoprostenol; Hydrocortisone; Isotope Labeling; Organ Culture Techniques; Osteoblasts; Oxytocics; Phosphodiesterase Inhibitors; Prostaglandin D2; Prostaglandins E, Synthetic; Prostaglandins F, Synthetic; Rats; Signal Transduction; Thymidine; Tritium

1. In segments of the rat vena cava preincubated with [3H]-noradrenaline and superfused with physiological salt solution (containing desipramine and corticosterone), we studied the effects of prostaglandins of the D, E and F series, of a prostacyclin analogue and a thromboxane-mimetic and of subtype-selective prostaglandin E-receptor (EP-receptor) ligands on the electrically (0.66 Hz)-evoked tritium overflow. 2. The electrically-evoked tritium overflow was inhibited by prostaglandin E2 (maximum inhibition by about 80%; pIC40 7.49). The effect of prostaglandin E2 was not affected by rauwolscine, which, by itself, increased the evoked overflow; the alpha 2-adrenoceptor antagonist was added to the superfusion medium in all subsequent experiments. Indomethacin failed to affect either the evoked tritium overflow or its inhibition by prostaglandin E2. 3. The inhibitory effect of prostaglandin E2 on the electrically-evoked tritium overflow was not altered by the EP1-receptor antagonist. AH 6809 (6-isopropoxy-9-oxoxanthene-2-carboxylic acid) at a concentration at least 30 fold higher than its pA2 value at EP1-receptors. The following compounds mimicked the effect of prostaglandin E2 showing the following rank order of potencies: misoprostol (EP2-/EP3-receptor agonist) congruent to sulprostone (EP1-/EP3-receptor agonist) congruent to prostaglandin E1 = prostaglandin E2 >> iloprost (EP1-/IP-receptor agonist) = prostaglandin F2 alpha. The evoked overflow was not affected by high concentrations of prostaglandin D2 or the thromboxane-mimetic U46619 (9,11-dideoxy-11 alpha, 9 alpha-epoxy-methano-prostaglandin F2 alpha). 4. The present results suggest that the postganglionic sympathetic nerve fibres innervating the rat vena cava are endowed with presynaptic EP3-receptors.They are not tonically activated by endogenously formed products of cyclo-oxygenase and do not interact with the presynaptic M2-adrenoceptors.

Topics: Alprostadil; Animals; Dinoprost; Dinoprostone; Electric Stimulation; Indomethacin; Misoprostol; Norepinephrine; Prostaglandin Antagonists; Prostaglandin D2; Prostaglandins; Rats; Receptors, Prostaglandin; Receptors, Prostaglandin E; Vena Cava, Inferior; Xanthenes; Xanthones; Yohimbine