Platelet Permeabilization

Methods of platelet permeabilization have been used for more than 20 yr as a means to study the role of various intracellular molecules in platelet function (1 –3 ). Initially, permeabilization of platelets was used largely to introduce cations, nucleotides, and other small molecules into platelets. Since platelets are anucleate, it is more difficult to express proteins in these cells. Thus, permeabilization represents the most convenient method by which to introduce recombinant proteins into platelets. Inhibitory antibodies and peptides have also been dialyzed into permeabilized platelets in order to assess the role of specific proteins in platelet physiology. Several methods of permeabilizing platelet membranes have been described. The decision of which method to use will depend on the application for which the permeabilization procedure is being performed. This chapter will describe the use of bacterial toxins as permeabilizing agents. Detailed descriptions of alternative methods for platelet permeabilization (e.g., by electroporation or by detergents such as saponin and digitonin) have been described elsewhere (4 ).