Preconditioning (PC) is one of the most effective strategies to reduce the severity of cell damage, in particular of nervous tissue cells. Although PC mechanisms are studied insufficiently, it is clear that proteases are involved in them, but their role has yet been not studied in detail. In this work, some mechanisms of a potential recruiting of proteases in PC are considered. Our attention is mainly focused on the protease families of caspases and cathepsins and on protease receptors. We present evidence that just these proteins are involved in the PC of brain cells. A hypothesis is proposed that secreted cathepsin B is involved in the realization of PC through activation of PAR2 receptor.