title: Clostridium perfringens alpha-toxin-induced hemolysis of horse erythrocytes is dependent on Ca2+ uptake.
abstract: Clostridium perfringens alpha-toxin is able to lyse various erythrocytes. Exposure of horse erythrocytes to alpha-toxin simultaneously induced hot-cold hemolysis and stimulated production of diacylglycerol and phosphorylcholine. When A23187-treated erythrocytes were treated with the toxin, these events were dependent on the concentration of extracellular Ca2+ . Incubation with the toxin of BAPTA-AM-treated horse erythrocytes caused no hemolysis or production of phosphorylcholine, but that of the BAPTA-treated erythrocytes did. When Quin 2-AM-treated erythrocytes were incubated with the toxin in the presence of 45Ca2+, the cells accumulated 45Ca2+ in a dose- and a time-dependent manner. These results suggest that the toxin-induced hemolysis and hydrolysis of phosphatidylcholine are closely related to the presence of Ca2+ in the cells. Flunarizine, a T-type Ca2+ channel blocker, and tetrandrine, an L- and T-type Ca2+ channel blocker, inhibited the toxin-induced hemolysis and Ca2+ uptake. However, L-type Ca2+ channel blockers, nifedipine, verpamil and diltiazem, an N-type blocker, omega-conotoxin SVIB, P-type blockers, omega-agatoxin TK and omega-agatoxin IVA, and a Q-type blocker, omega-conotoxin MVII C, had no such inhibitory effect. The observation suggests that Ca2+ taken up through T-type Ca2+ channels activated by the toxin plays an important role in hemolysis induced by the toxin.
authors.affiliation: Department of Microbiology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
authors.forename: Sadayuki
authors.initials: S
authors.lastname: Ochi
authors.forename: Masataka
authors.initials: M
authors.lastname: Oda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nagahama
authors.forename: Jun
authors.initials: J
authors.lastname: Sakurai
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D001692:Biological Transport; D002118:Calcium / Q000097:blood*; D002135:Calcium-Binding Proteins / Q000633:toxicity*; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects*; D006461:Hemolysis / Q000187:drug effects* / Q000502:physiology; D006736:Horses; D007700:Kinetics; D010738:Type C Phospholipases / Q000633:toxicity*
chemical_list: D001427:Bacterial Toxins; D002135:Calcium-Binding Proteins; D002614:Chelating Agents; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D010738:Type C Phospholipases; C040649:alpha toxin, Clostridium perfringens; D002118:Calcium