AMP-activated　protein　kinase　(AMPK)　protects　various　tissues　and　cells　from　ischemic　insults　and　is　activated　by　many　stimuli　including　mechanical　stretch.　Therefore,　this　study　investigated　if　the　activation　of　AMPK　is　involved　in　stretch-induced　cardioprotection　(SIC).　Intraventricular　balloon　and　aorto-caval　shunt　(ACS)　were　used　to　stretch　rat　hearts　ex　vivo　and　in　vivo,　respectively.　Stretch　preconditioning　reduced　myocardial　infarct　induced　by　ischemia-reperfusion　(I/R)　and　improved　post-ischemic　functional　recovery.　Phosphorylation　of　AMPK　and　its　downstream　substrate,　acetyl-CoA　carboxylase　(ACC)　were　increased　by　mechanical　stretch　and　ACC　phosphorylation　was　completely　blocked　by　the　AMPK　inhibitor,　Compound　C.　AMPK　activator　(AICAR)　mimicked　SIC.　Gadolinium,　a　blocker　of　stretch-activated　ion　channels　(SACs),　inhibited　the　stretch-induced　phosphorylation　of　AMPK　and　ACC,　whereas　diltiazem,　a　specific　L-type　calcium　channel　blocker,　did　not　affect　AMPK　activation.　Furthermore,　SIC　was　abrogated　by　Compound　C　and　gadolinium.　The　in　vivo　stretch　induced　by　ACS　increased　AMPK　activation　and　reduced　myocardial　infarct.　These　findings　indicate　that　stretch　preconditioning　can　induce　the　cardioprotection　against　I/R　injury,　and　activation　of　AMPK　plays　an　important　role　in　SIC,　which　might　be　mediated　by　SACs.