title: Studies on the toxic effects of streptolysin 'O': effect on the contractility of isolated and intact mammalian and amphibian heart.
abstract: The effect of streptolysin O (a streptococcal exotoxin) on the myocardial contractility of isolated and intact mammalian and amphibian heart has been investigated. Streptolysin O caused marked reduction or complete cessation of myocardial contractility of mammalian and amphibian heart both in vivo and in vitro. The effect of submaximal doses of streptolysin O on isolated atria was reversible after repeated washings and the myocardial depressant effect of streptolysin O on isolated atria was reversible after repeated washings and the myocardial depressant effect of streptolysin O was not antagonised by atropine. These observations would suggest that streptolysin O is cardiotoxic and may be involved in the causation of myocardial failure associated with acute rheumatic fever in man.
mesh_terms: D000818:Animals; D016275:Atrial Function; D001285:Atropine / Q000494:pharmacology; D002415:Cats; D003864:Depression, Chemical; D004285:Dogs; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D011817:Rabbits; D051381:Rats; D013301:Streptolysins / Q000494:pharmacology*; D016276:Ventricular Function
chemical_list: D013301:Streptolysins; D001285:Atropine