Measurements of 1,2-diacylglycerol and ceramide in hearts subjected to ischemic preconditioning.
An accumulation of recent evidence suggests that the mechanism in ischemic preconditioning (IPC) may involve the activation of protein kinase C (PKC) regulatory pathway. In this study, we examined whether the content of 1,2-diacylglycerol (1,2-DAG) and ceramide, which are intracellular second messengers regulating PKC activity, change during IPC in isolated perfused rat hearts, and whether the observed change in 1,2-DAG is accompanied with alteration in its fatty acid composition. Hearts subjected to IPC, consisting of 5-min transient global ischemia followed by 5-min reperfusion, presented a significant functional recovery during subsequent 40-min reperfusion following 40-min global ischemia compared with non-preconditioned hearts. An increase in 1,2-DAG content was observed in hearts subjected to 5-min transient ischemia compared with non-ischemic control hearts, however this was not seen in hearts harvested after 5-min reperfusion following 5-min ischemia. While fatty acid composition in 1,2-DAG was virtually unchanged in hearts subjected to 5-min ischemia, saturated 1,2-DAG decreased and monounsaturated/polyunsaturated 1,2-DAG increased in hearts reperfused for 5-min following 5-min ischemia compared with the non-ischemic control hearts. Ceramide mass did not change significantly, suggesting that the contribution of ceramide may be small in IPC. These data are in concert with the hypothesis that 1,2-DAG is a second messenger in IPC and the changes in fatty acid composition of 1,2-DAG may add new insight concerning signal transduction pathway in IPC.
Murase
K
K
Internal Medicine II, Nagoya University School of Medicine, Japan. mura2@tsuru.med.nagoya-u.ac.jp
Okumura
K
K
Hayashi
K
K
Matsui
H
H
Toki
Y
Y
Ito
T
T
Hayakawa
T
T
D000818:Animals; D002518:Ceramides / Q000032:analysis*; D004075:Diglycerides / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis; D006321:Heart / Q000503:physiopathology; D019194:Ischemic Preconditioning; D008297:Male; D009206:Myocardium / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar
C011439:1,2-diacylglycerol; D002518:Ceramides; D004075:Diglycerides; D005227:Fatty Acids