Evidence of protein kinase C translocation by ischemic preconditioning in global ischemia model.
We tested recent evidence that ischemic preconditioning (PC) involves in translocation of protein kinase C (PKC) from the cytosol to myocyte membrane. Isolated Langendorff-perfused rabbit hearts (n=96) were subjected to 60 or 45 min of ischemia (I) and 120 min of reperfusion (R) with or without PC (4 cycles of 5 min I and 5 min R; or single dose of 5 min I and 10 min R), respectively. Left ventricular function and infarct size (IS) were measured; myocardial cytosolic and membrane PKC activity were determined by 32P-gamma-ATP incorporation into PKC-specific peptide. PC enhanced improvement of functional recovery and reduced IS (26.9+/-1.4% versus 15.3+/-1.9%, p<0.01, in 60 min of I; 18.3+/-2.6% versus 8.6+/-2.5%, p<0.05, in 45 min of I); cytosolic PKC activity decreased 74% of total activity (p<0.05) both in 60 and 45 min of I; membrane PKC activity increased (1.7-fold of baseline, p<0.01, in 60 min of I; 1.8-fold, p<0.01, in 45 min of I; 1.5-fold, p<0.05, in 60 of min I and 120 min of R). From these results, it is concluded that translocation of PKC from the cytosol to myocyte membranes is an important mechanism responsible for PC effect.
Kim
H
H
Department of Histology, College of Medicine, Chung-Ang University, Seoul, Korea.
Kim
D J
DJ
Chung
H S
HS
Shim
S J
SJ
Yoo
U H
UH
Rah
B J
BJ
Kim
H D
HD
D000818:Animals; D001692:Biological Transport; D004195:Disease Models, Animal; D019157:Ischemic Preconditioning, Myocardial; D009206:Myocardium / Q000201:enzymology*; D011493:Protein Kinase C / Q000378:metabolism*; D011817:Rabbits
D011493:Protein Kinase C