Snake venom cardiotoxin can rapidly induce actin polymerization in intact platelets.

The action of Taiwan cobra (Naja naja atra) venom cardiotoxin on rabbit platelets at 37 degrees C was characterized by observing cytoskeletal alterations and cell lysis. At a concentration of 21.4 microM the toxin produced no cell lysis within 30 s, and less than 5% of the total lactate dehydrogenase activity of intact cells was detected in the suspending medium after the interaction had proceeded for 3 min. The extent of cell lysis was proportional to toxin concentration and interaction time. Before cell lysis, the toxin caused rapid incorporation of actin monomers into cross-linked actin filaments. The actin incorporation could be inhibited by either the presence of cytochalasin B or increased CaCl2 concentration in the suspending medium. However, addition of indomethacin did not influence the toxin-induced cytoskeletal change.