title: Antagonism of some contractile responses to prostaglandins by cyproheptadine.
abstract: In the present study antagonism of the contractile responses to PGE1 and PGF2 alpha, by cyproheptadine on isolated rat stomach strip, rabbit uterus, guinea-pig ileum and rabbit jejunum is documented. Cyproheptadine blocks the responses to PGE1, PGF2 alpha, acetylcholine, 5-hydroxytryptamine in extremely small concentrations varying from 10 ng to 1 microgram/ml. The blockade is persistant, provided the exposure is prolonged. However, it does not antagonise the responses of adrenaline on guinea-pig seminal vesicle. Polyphloretine phosphate was used in the concentration of 2.5 to 100 micrograms/ml on the rat stomach strip, rabbit jejunum and rabbit uterus; it failed to produce any blockade of contractile responses to prostaglandins. It is concluded that cyproheptadine nonspecifically antagonised the responses to acetylcholine, 5-hydroxytryptamine, PGE1 and PGF2 alpha in extremely small concentrations.
mesh_terms: D000779:Anesthetics, Local; D000818:Animals; D001001:Anura; D003533:Cyproheptadine / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007583:Jejunum / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D011121:Polyphloretin Phosphate / Q000494:pharmacology; D011448:Prostaglandin Antagonists; D051381:Rats; D012669:Seminal Vesicles / Q000187:drug effects; D013270:Stomach / Q000187:drug effects; D014590:Uterine Contraction / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D011448:Prostaglandin Antagonists; D003533:Cyproheptadine; D011121:Polyphloretin Phosphate