sulprostone and Disease-Models--Animal

The aim of our study was (1) the pharmacological characterization of EP(3) receptors in human pulmonary arteries and (2) the examination of the potential involvement of these receptors in the regulation of neurogenic tachycardia in pithed rats. L-826266 served as the EP(3) receptor antagonist.. Experiments were performed on isolated human pulmonary arteries and pithed rats.. The prostanoid EP(1)/EP(3) receptor agonist sulprostone (1 nM - 100 μM) concentration-dependently contracted isolated human pulmonary arteries (pEC50, 6.88 ± 0.10). The EP(1) receptor antagonist SC 19920 (100 μM) did not affect the vasoconstriction induced by sulprostone, the TP receptor antagonist sulotroban (10 μM) only slightly attenuated the effects elicited by sulprostone >>3 μM, whereas L-826266 (10 μM) shifted its concentration-response curve to the right (apparent pA(2) value 6.18; incubation time 0.5 h). In rings exposed to L-826266 (0.1, 1 or 10 μM) for 3 h, a concentration-dependent inhibitory effect against the sulprostone-induced vasoconstriction was obtained, yielding a Schild plot-based pA(2) value of 7.39. In pithed rats, sulprostone (10 - 1,000 nmol/kg), but not the IP/EP(1) receptor agonist iloprost (1-100 nmol/kg), inhibited the electrically evoked increase in heart rate (HR) dose-dependently, maximally by at least 80%. L-826266 (3 μmol/kg) did not affect basal HR and diastolic blood pressure, but reduced the inhibitory effect of sulprostone 1,000 nmol/kg by about 20%.. EP(3) receptors (1) located postsynaptically strongly contract human pulmonary arteries and (2) located presynaptically on sympathetic nerve fibers supplying the heart of pithed rats strongly inhibit the neurogenic tachycardia.

Topics: Acrylamides; Aged; Animals; Decerebrate State; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Heart; Heart Rate; Humans; Iloprost; Male; Middle Aged; Naphthalenes; Pulmonary Artery; Rats; Rats, Wistar; Receptors, Prostaglandin E, EP3 Subtype; Signal Transduction; Sulfonamides; Sympathetic Nervous System; Tachycardia; Vasoconstriction

Prostaglandin (PG) E(2) is thought to exert protective effects in the lungs. Accordingly, aerosolized PGE(2) prevents the experimentally induced airway response to allergen challenge in asthmatics. In vitro evidence indicating that functional PGE(2) receptors (EP) are expressed on human mast cells and that PGE(2) can alter cytokine production suggests that these phenomena may be involved in its beneficial effect in asthma. However, in vivo evidence is scarce.. We assessed the effects of exogenous PGE(2) and of the EP1/EP3 agonist sulprostone on the murine airway response to house dust mite (HDM) allergens, a model that accurately reproduces the spontaneous exposure of allergic asthma patients to aeroallergens. We also analyzed the in vivo impact of PGE(2) on production in the murine airway of mast cell protease (mMCP)-1, a specific marker of lung mast cell activity, and on local production of cytokines.. Exogenous PGE(2), but not sulprostone, reduced eosinophilic infiltration in HDM-sensitized mice by half and led to a strong reduction in airway Th(2) cytokine expression. These anti- inflammatory effects were accompanied in vivo by a substantial reduction in HDM-induced upregulation of airway mMCP-1. Neither PGE(2) nor sulprostone had any effect on airway hyperresponsiveness to methacholine.. Our results indicate that the anti-inflammatory effect of PGE(2) can be reproduced in vivo in HDM-sensitized mice and suggest that this protective effect is dependent in vivo on inhibition of the allergen-triggered proinflammatory activity of bronchial mast cells. Finally, the effect of PGE(2) is linked to reduced upregulation of airway Th(2) cytokines.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Asthma; Chemokine CCL2; Cytokines; Dinoprostone; Disease Models, Animal; Eosinophils; Female; Infusions, Subcutaneous; Lung; Mast Cells; Methacholine Chloride; Mice; Mice, Inbred BALB C; Pulmonary Eosinophilia; Pyroglyphidae; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP3 Subtype; Th2 Cells

The most common preclinical models of neuropathic pain involve surgical ligation of sensory nerves, which is especially difficult in mice. Transient models of chemically sensitized allodynia are potentially useful for rapidly characterizing the analgesic profile of compounds and conducting mechanistic studies.. Increasing doses of NMDA, sulprostone (an EP1/EP3 prostaglandin receptor agonist) or phenylephrine (an alpha (1) adrenoceptor agonist) were injected intrathecally (i.t.) or i.p., and animals were subsequently assessed for allodynia. The effects of receptor antagonists and analgesic compounds on allodynia were also assessed.. A comparison of total body doses that cause allodynia following spinal or systemic administration indicated that NMDA induces allodynia in the spinal cord while sulprostone and phenylephrine act through a peripheral mechanism. Inhibition of the allodynia with receptor antagonists indicated that each agent induces allodynia by a distinct mechanism. The three models were benchmarked using compounds known to be active in neuropathic pain patients and nerve injury animal models, including gabapentin, amitriptyline and clonidine.. These transient allodynia models are a useful addition to the toolbox of preclinical pain models. They are simple, rapid and reproducible, and will be especially useful for characterizing the pain phenotype of knockout mice.

Topics: Adrenergic alpha-Antagonists; Amines; Amitriptyline; Analgesics; Animals; Clonidine; Cyclohexanecarboxylic Acids; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Excitatory Amino Acid Antagonists; Gabapentin; gamma-Aminobutyric Acid; Hyperalgesia; Injections, Intraperitoneal; Injections, Spinal; Male; Memantine; Mice; Mice, Inbred C57BL; Morphine; N-Methylaspartate; Pain; Peripheral Nervous System; Phenylephrine; Piperazines; Prostaglandin Antagonists; Rats; Rats, Sprague-Dawley; Receptors, Adrenergic, alpha-1; Receptors, N-Methyl-D-Aspartate; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Reproducibility of Results; Spinal Cord; Spinal Nerves; Time Factors

The present study examined the hypothesis that prostaglandin E2 (PGE2) through activation of prostaglandin E (EP) receptor contributes to endothelium-dependent contractions.. Western blotting revealed that the protein expression of EP1 receptor was significantly down-regulated in the aorta of the spontaneously hypertensive rat (SHR), but there was no significant difference in the expression of EP2, EP4, and total EP3 receptors between preparations of Wistar Kyoto rats (WKY) and SHR. Isometric tension studies showed that low concentrations of PGE2 caused endothelium-dependent relaxations in WKY but not in aortas of the SHR. High concentrations of PGE2 evoked contractions predominately through the activation of thromboxane-prostanoid (TP) receptors in the WKY, but involves the dual activation EP and TP receptors in the SHR. SQ29,548, BAYu3405 and Terutroban (TP receptor antagonists), and AH6809 (non-selective EP receptor antagonist) abolished, while SC19220 (preferential EP1 receptor antagonist) did not inhibit endothelium-dependent contractions. Both SC19220 and AH6809 significantly inhibited contractions to U46619 (TP receptor agonist).. The present study demonstrates that the contraction caused by PGE2 in the SHR aorta is dependent on the activation of EP1 and TP receptors, but that endothelium-dependent contractions do not require the former. Thus, PGE2 is unlikely to be an endothelium-derived contracting factor in this artery. The ability of AH6809 to inhibit endothelium-dependent contractions can be attributed to its partial antagonism at TP receptors. Nevertheless, the impairment of PGE2-mediated relaxation may contribute to endothelial dysfunction in the aorta of the SHR.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Aorta, Thoracic; Blotting, Western; Bridged Bicyclo Compounds, Heterocyclic; Carbazoles; Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium, Vascular; Fatty Acids, Unsaturated; Hydrazines; Hypertension; Immunohistochemistry; Naphthalenes; Phenylephrine; Potassium Chloride; Propionates; Prostaglandin Antagonists; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Thromboxane; Sulfonamides; Vasoconstriction; Vasoconstrictor Agents; Vasodilation; Xanthones

Recent studies suggest that the inducible isoform of cyclooxygenase, COX-2, promotes motor neuron loss in rodent models of ALS. We investigated the effects of PGE2, a principal downstream prostaglandin product of COX-2 activity, on motor neuron survival in an organotypic culture model of ALS. We find that PGE2 paradoxically protects motor neurons at physiological concentrations in this model. PGE2 exerts its downstream effects by signaling through a class of four distinct G-protein-coupled E-prostanoid receptors (EP1-EP4) that have divergent effects on cAMP. EP2 and EP3 are dominantly expressed in ventral spinal cord in neurons and astrocytes, and activation of these receptor subtypes individually or in combination also rescued motor neurons. The EP2 receptor is positively coupled to cAMP, and its neuroprotection was mimicked by application of forskolin and blocked by inhibition of PKA, suggesting that its protective effect is mediated by downstream effects of cAMP. Conversely, the EP3 receptor is negatively coupled to cAMP, and its neuroprotective effect was blocked by pertussis toxin, suggesting that its protective effect is dependent on Gi-coupled heterotrimeric signaling. Taken together, these data demonstrate an unexpected neuroprotective effect mediated by PGE2, in which activation of its EP2 and EP3 receptors protected motor neurons from chronic glutamate toxicity.

Topics: Alprostadil; Amyotrophic Lateral Sclerosis; Animals; Animals, Newborn; Astrocytes; Cell Count; Cyclic AMP; Dinoprostone; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Enzyme Inhibitors; Immunohistochemistry; Motor Neurons; Neurofilament Proteins; Organ Culture Techniques; Pertussis Toxin; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, Prostaglandin E; Spinal Cord; Statistics, Nonparametric