title: The effects of time and indomethacin on contractile responses of the guinea-pig gall bladder in vitro.
abstract: 1. The effects of time and of indomethacin on contractile responses of the guinea-pig gall bladder were studied in vitro. 2. The tissues contracted to field stimulation at 5 Hz (in the absence and presence of atropine 10(-6) M). (-)-noradrenaline (10(-5) M), acetylcholine (10(-5) M), and adenosine 5'-triphosphate (ATP, 10(-4) M); the magnitude of the contractile responses increased with time. 3. (-)-Isoprenaline 10(-5) M either relaxed (17 of 23 preparations tested) or had no effect on gall bladder strips. 4. The responses of strips of guinea-pig gall bladder to field stimulation at 5 Hz (in the absence or presence of atropine 10(-6) M), (-)-noradrenaline (10(-5) M), and acetylcholine (10(-5) M) obtained 4 h 45 min after setting up the tissue were reduced following incubation with indomethacin (7.9 x 10(-6) M for 1 h). The responses to (-)-isoprenaline (10(-5) M) and to ATP (10(-4) M) were abolished by incubation with indomethacin. 5. These results suggest that, in the guinea-pig gall bladder in vitro, the magnitude of the contractile responses to field stimulation at 5 Hz, (-)-noradrenaline (10(-5) M), and acetylcholine (10(-5) M) and the ability of the tissue to respond to (-)-isoprenaline (10(-5) M) and ATP (10(-4) M), may be dependent on the synthesis of a prostaglandin-like substance.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D005260:Female; D005704:Gallbladder / Q000187:drug effects*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D013997:Time Factors
chemical_list: D001285:Atropine; D000255:Adenosine Triphosphate; D000109:Acetylcholine; D009638:Norepinephrine; D007213:Indomethacin