title: Eserine-induced hypertone of guinea pig distal colon in vivo: a new pharmacological procedure for testing smooth muscle relaxants.
abstract: A new in vivo procedure suitable for testing the smooth muscle relaxant properties of a test substance is described. Topical eserine produced a long-lasting steady increase in tone of guinea pig distal colon and enhanced the atropine-sensitive phasic activity. Intravenously administered atropine, pirenzepine, and dicyclomine (which possess competitive antimuscarinic properties) produced a dose-related inhibition of eserine-induced muscle tone and suppressed phasic contractions. On the other hand, verapamil and octylonium bromide (which produce smooth muscle relaxation by interfering with Ca++ availability for contraction) did not suppress phasic contraction although they were fully effective in inhibiting eserine-induced tone. The eserine-induced contraction of guinea pig distal colon appears to be a suitable, quick, and inexpensive test for evaluating the effects of potential smooth muscle relaxants against background hypermotility produced by amplifying the neurogenic drive to the target organ.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001570:Benzodiazepinones / Q000494:pharmacology; D003106:Colon / Q000187:drug effects; D004025:Dicyclomine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D008297:Male; D008722:Methods; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010276:Parasympatholytics / Q000494:pharmacology*; D010830:Physostigmine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D010890:Pirenzepine; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D001570:Benzodiazepinones; D010276:Parasympatholytics; D000644:Quaternary Ammonium Compounds; C013934:octylonium; D010890:Pirenzepine; D004025:Dicyclomine; D001285:Atropine; D010830:Physostigmine; D014700:Verapamil