Fig. 5. Infarct size was determined using 1% triphenyltetrazolium chloride staining, as described in the Materials and Methods section. Areas infarcted  in vivo by coronary artery ligation were excluded from infarct size determination (  A ). The scarred chronic infarct (  white ) resulting from coronary ligation was clearly distinguished from fresh infarcts (  salmon pink ). Release of lactate dehydrogenase (LDH) during reperfusion (  B ) served as an independent method to estimate infarct size (see Materials and Methods). Transverse sections of representative experiments (  C ). DMSO = dimethyl sulfoxide (< 0.1%; used to dissolve LY294002); ISCH = unprotected remodeled hearts exposed to ischemia–reperfusion alone; LY = LY294002 (15 μm); PostC = anesthetic postconditioning. Data are given as mean ± SD (n = 5 in each group). *  P < 0.05  versus ISCH.