Cytoskeletal assembly induced by receptor-dependent or independent activation of bovine platelets was investigated. When platelets were preactivated with receptor-dependent stimulus, ADP or thrombin, cytoskeletal assembly was not induced repeatedly by the same agonist. However, in the case of receptor-independent stimulus, cryo-activation, the assembly was induced not only by receptor-dependent but also by independent stimulus. The desensitization, therefore, lies in the transmission of stimuli from receptors to cytoskeletal proteins.