title: Iloprost: intracellular Ca(2+)-dependent contractile effect on isolated smooth muscle cells from guinea-pig ileum.
abstract: Prostaglandin E2 (PGE2) and iloprost induced a concentration-dependent contraction of smooth muscle cells isolated from the circular layer of guinea-pig ileum. PGE2- and iloprost-induced contractions were inhibited by the selective EP1-receptor antagonist, SC19220 (1-acetyl-2-(8-chloro-10, 11-dihydrodibenz (b,f) (1,4) oxazepine-10-carbonyl)-hydrazine), indicating the involvement of the EP1 subtype of the PGE2 receptor. When cells were incubated for 10 min in the presence of strontium (4 mM L-1), an inhibitor of the release of Ca2+ from intracellular store, the contractile effect of PGE2 and iloprost was inhibited. In contrast, incubation of cells in Ca/2+)-free medium, Ca(2+)-free medium plus EGTA, or in the presence of nifedipine, an organic Ca(2+)-channel blocker, did not alter the PGE2- and iloprost-induced contraction. These observations suggest that the myogenic effect of PGE2 and iloprost on intestinal smooth muscle is dependent on the release of intracellular calcium.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D012531:Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D019004:Galanin / Q000378:metabolism; D006168:Guinea Pigs; D007082:Ileum / Q000166:cytology / Q000187:drug effects; D016285:Iloprost / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects*; D009479:Neuropeptides / Q000378:metabolism; D011982:Receptors, Prostaglandin / Q000037:antagonists & inhibitors; D012844:Sincalide / Q000494:pharmacology; D013324:Strontium / Q000494:pharmacology
chemical_list: D009479:Neuropeptides; D011982:Receptors, Prostaglandin; D012531:Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; D019004:Galanin; D016285:Iloprost; D015232:Dinoprostone; D012844:Sincalide; D002118:Calcium; D013324:Strontium