Arguments in favor of protein kinase C playing an important role in ischemic preconditioning

In light of the above we believe that the PKC hypothesis is alive and well. Why then do PKC inhibitors fail to block protection in pig and perhaps dog heart? Those observations argue against PKC playing a universal role in all models of preconditioning. The receptor pathway for preconditioning in the rabbit heart has been found to be highly redundant with no less than 4 substances including adenosine (12), bradykinin (8), opioids (15), and free radicals (5) contributing in parallel to the protection. Preconditioning appears to be very important to the heart. It is not inconceivable, then, that alternative pathways have also developed around PKC in some species to further insure that the ischemic heart would become preconditioned. Whatever the case, it should be remembered that the available human data still support the PKC hypothesis in that rather important species.