Relaxation induced by serotonin and sumatriptan in isolated guinea pig gallbladder strips.
The effects of 5-hydroxytryptamine (5-HT) and sumatriptan were investigated on isolated guinea pig gallbladder strips. While 0.1 microM-50 mM of 5-HT exhibited contractile and/or relaxant effects in quiescent preparations, the same concentrations of sumatriptan did not. On the other hand, carbachol-precontracted tissues were relaxed by the same amounts of 5-HT and sumatriptan in a concentration-dependent manner. The relaxant responses to 5-HT were not antagonized or changed by tetrodotoxin, indomethacin, capsaicin, NG-nitro-L-arginine (L-NOARG), GR55562 [(+/-)-propranolol, 3-[3-(N,N-dimethylamino)propyl 1-4-hydroxy-N-[4-(pyridin-4-yl)phenyl]benzamide , S(-)-propranolol, methysergide, ketanserin. tropisetron, GR 113808 ([1-[2-(methylsulphonylamino)ethyl -4-piperidinyl]methyl-1-methyl-1H-indole-3-carboxylate maleate salt). pargyline, and fluvoxamine. The relaxant responses to sumatriptan were antagonized by GR55562 but not by S(-)-propranolol. These results suggest that 5-HT and sumatriptan cause relaxation in carbachol-precontracted isolated guinea pig gallbladder strips by yet undefined mechanisms.
Emre-Aydíngöz
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Hacettepe University, Faculty of Medicine, Department of Pharmacology, Sihhiye, Ankara, Turkey.
Erdem
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Tuncer
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D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005704:Gallbladder / Q000187:drug effects* / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D011433:Propranolol / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D018170:Sumatriptan / Q000494:pharmacology*
D000319:Adrenergic beta-Antagonists; D001549:Benzamides; D016166:Free Radical Scavengers; D011725:Pyridines; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C103477:3-(3-(dimethylamino)propyl)-4-hydroxy-N-(4-(4-pyridinyl)phenyl)benzamide; D012701:Serotonin; D018170:Sumatriptan; D011433:Propranolol