title: Effect of cisapride on the isolated guinea pig gall bladder and common bile duct.
abstract: 1. In this study, the effect of cisapride on the isolated guinea pig gall bladder (GB) and common bile duct (CBD) motility was investigated. 2. Cisapride, up to a certain concentration, produced an increase in tone of the GB (EC50 1.35 x 10(-8) M) and the CBD (EC50 2.75 x 10(-9) M), whereas, at concentrations higher than 3 x 10(-5) M for the GB and 5 x 10(-6) M for the CBD, it produced a transient increase in tone followed by a sustained decrease in tone or in the contraction amplitude or in both. 3. The cisapride-induced increase in tone was antagonized by atropine on both the GB and the CBD. 4. Cisapride up to 2 x 10(-5) M for the GB and 3 x 10(-6) M for the CBD did not modify, whereas, at concentrations higher than 2.8 x 10(-5) M for the GB and 4 x 10(-6) M for the CBD, it antagonized, noncompetitively, the concentration-response curve to exogenously applied acetylcholine. The IC50 values for cisapride on the EC50 of acetylcholine on the GB and the CBD were 9.4 x 10(-5) M and 8.2 x 10(-6) M, respectively. 5. In conclusion, on the guinea pig GB and CBD, low concentrations of cisapride produce a stimulating effect, probably of cholinergic origin, whereas higher concentrations produce a transient stimulating effect, probably of cholinergic origin, followed by a sustained relaxing effect, which may involve both cholinergic and noncholinergic pathways.
authors.affiliation: Department of Pharmacology, Faculty of Veterinary Medicine, Aristotelian University, Thessaloniki, Greece.
authors.forename: M
authors.initials: M
authors.lastname: Koutsoviti-Papadopoulou
authors.forename: G
authors.initials: G
authors.lastname: Kounenis
authors.forename: G
authors.initials: G
authors.lastname: Batzias
authors.forename: V
authors.initials: V
authors.lastname: Elezoglou
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D017776:Autonomic Pathways / Q000187:drug effects; D020117:Cisapride; D003135:Common Bile Duct / Q000187:drug effects*; D005260:Female; D005704:Gallbladder / Q000187:drug effects*; D005765:Gastrointestinal Agents / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects*; D010275:Parasympathetic Nervous System / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology*
chemical_list: D005765:Gastrointestinal Agents; D010276:Parasympatholytics; D010880:Piperidines; D001285:Atropine; D000109:Acetylcholine; D020117:Cisapride