title: Lethal effects and cardiovascular effects of purified alpha- and theta-toxins from Clostridium perfringens.
abstract: Shock, a common and frequently fatal manifestation of gas gangrene caused by Clostridium perfringens, is probably mediated by extracellular toxins. Previous studies implicating alpha-toxin as the major lethal factor were frequently done with preparations contaminated with a second lethal factor, theta-toxin. We purified alpha- and theta-toxins from C. perfringens and demonstrated that both were lethal to mice. We investigated the effects of these purified toxins on cardiovascular function in intact rabbits; both toxins caused profound hypotension and bradycardia within 40 min. Reduced cardiac output preceded the development of hypotension and bradycardia. Purified alpha-toxin produced a dose-dependent reduction in myocardial function in isolated rabbit atrial preparations. Purified theta-toxin did not directly inhibit myocardial function. Shock induced by alpha-toxin may be partly mediated by direct depression of myocardial function. theta-Toxin reduced cardiac output in intact animals but had no direct effects on isolated heart preparations at concentrations that induced shock in intact animals. These data suggest that theta-toxin-induced shock could be mediated by an endogenous myocardial depressant factor.
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D001794:Blood Pressure / Q000187:drug effects; D002135:Calcium-Binding Proteins; D002302:Cardiac Output / Q000187:drug effects; D003016:Clostridium perfringens; D005260:Female; D005738:Gas Gangrene / Q000150:complications*; D006321:Heart / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006460:Hemolysin Proteins / Q000633:toxicity; D008297:Male; D051379:Mice; D011817:Rabbits; D012772:Shock, Septic / Q000209:etiology*; D010738:Type C Phospholipases
chemical_list: D001427:Bacterial Toxins; D002135:Calcium-Binding Proteins; D006460:Hemolysin Proteins; C020452:Clostridium perfringens theta-toxin; D010738:Type C Phospholipases; C040649:alpha toxin, Clostridium perfringens