title: Pharmacological characterization of pre- and postsynaptic prostanoid receptors in pig gastric fundus.
abstract: This study characterized the subtype of prostanoid receptors on the cholinergic neurones and smooth muscle cells in circularly oriented muscle strips of the pig gastric fundus. Tissues were electrically stimulated (40 V, 4 Hz, 0.25 ms, 2 min) to induce tritium outflow after incubation with [3H]-choline. Indomethacin increased the electrically induced tritium outflow, suggesting an inhibitory effect of endogenous prostanoids. In the presence of indomethacin, PGE2 > PGF2alpha >PGI2 inhibited tritium release while the TP-receptor agonist U-46619 and PGD2 had no effect. The EP2-receptor agonist butaprost had no effect while the EP1- and EP3-receptor agonist sulprostone mimicked the effect of PGE2. The effect of sulprostone was not affected by AH 6809, that antagonizes EP1- and EP2-receptors, suggesting the presence of presynaptic EP3-receptors on the cholinergic nerve endings. All prostanoid receptor agonists, except butaprost, contracted the tissues concentration-dependently; the rank order of potency (U-46619 > sulprostone > PGE2 > PGF2alpha > PGD2 = PGI2) suggests the presence of TP- and EP1- and EP3-receptors on the circular smooth muscle cells.
authors.affiliation: Ghent University, Heymans Institute of Pharmacology, Faculty of Medicine and Health Sciences, De Pintelaan 185, B-9000 Ghent, Belgium.
authors.forename: Ole
authors.initials: O
authors.lastname: De Backer
authors.forename: Pascal G
authors.initials: PG
authors.lastname: Leclere
authors.forename: Romain A
authors.initials: RA
authors.lastname: Lefebvre
mesh_terms: D000818:Animals; D002794:Choline / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015237:Dinoprost / Q000494:pharmacology; D015232:Dinoprostone / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004558:Electric Stimulation; D011464:Epoprostenol / Q000494:pharmacology; D005748:Gastric Fundus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008600:Menstruation-Inducing Agents / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D011189:Potassium Chloride / Q000378:metabolism; D011453:Prostaglandins / Q000378:metabolism; D018078:Receptors, Prostaglandin E / Q000378:metabolism*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D013552:Swine; D014316:Tritium / Q000378:metabolism
chemical_list: D016861:Cyclooxygenase Inhibitors; D008600:Menstruation-Inducing Agents; D011453:Prostaglandins; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D014316:Tritium; C016767:sulprostone; D011189:Potassium Chloride; D015237:Dinoprost; D011464:Epoprostenol; D015232:Dinoprostone; D002794:Choline; D007213:Indomethacin