Stimulating action of catecholamines on isolated preparations of the rat colon and human and rabbit taeniae coli.
1. Adrenaline and noradrenaline induced dose related relaxations of the superfused rat colon. The relaxations were progressively transformed into contractions when beta-adrenoceptors were blocked with increasing doses of oxprenolol.2. Since phentolamine or phenoxybenzamine inhibited the contractions induced by adrenaline or noradrenaline in the presence of oxprenolol, it is assumed that the contractions are caused by stimulation of excitatory alpha-adrenoceptors.3. Human and rabbit taeniae coli showed responses that were qualitatively similar to those observed with the rat colon.
D000605:Amino Alcohols / Q000494:pharmacology; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology*; D003106:Colon / Q000187:drug effects*; D004837:Epinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011437:Propylamines / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011984:Sensory Receptor Cells / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects; D013565:Sympatholytics / Q000494:pharmacology
D000605:Amino Alcohols; D002395:Catecholamines; D011437:Propylamines; D013565:Sympatholytics; D009638:Norepinephrine; D004837:Epinephrine; D010646:Phentolamine