| Co-Investigator(Kenkyū-buntansha) |
KINUGAWA Koh-ichiro Univ.of Tokyo, Faculty of Medicine, Medical Fellow, 医学部(病), 医員
YAO Atsushi Univ.of Tokyo, Faculty of Medicine, Medical Fellow, 医学部(病), 医員
AOYAGI Teruhiko Univ.of Tokyo, Faculty of Medicine, Assistant Pro, 医学部(病), 助手
MOMOMURA Shin-ichi Univ.of Tokyo, Faculty of Medicine, Assistant Pro, 医学部(病), 助手 (10190985)
SERIZAWA Takashi Univ.of Tokyo, Faculty of Medicine, Lecturer Assistant Pro, 医学部(病), 講師 (90143429)
河本 修身 東京大学, 医学部(病), 医員
大谷 余志 東京大学, 医学部(病), 助手 (90203827)
|
|---|
| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1992: ¥1,400,000 (Direct Cost: ¥1,400,000)
|
|---|
| Research Abstract |
Recent studies have revealed that in many types of cells including cardiac myocytes immediate-early genes (IEG) and/or protein kinase cascade play important roles in recovering or adapting to various stresses or growth stimuli. In order to investigate how cardiac myocytes recover from a brief period of ischemia, we used a metabolic inhibition (MI) model, one of in vitro ischemia models, of chick embryo (10-day-old) ventricular myocytes to examine the induction of c-jun mRNA and the activity of mitogen-activated protein (MAP) kinase. We studied the levels of c-jun mRNA (RNA blot analysis), MAP kinase activity (in-gel kinase assay) and [Ca^<2+>] i (measured with indo-1) during MI using 1 mM sodium cyanide and 20 mM 2-deoxy-d-glucose and also during the recovery from MI.The relative abundance of c-jun mRNA (determined by laser densitometry) remained unchanged during MI of 30 min, but increased significantly during the recovery phase at 30,60,90,120 min (3.0,4.7,2.4,1.9-fold induction as c
… More
ompared with the pre-MI controls, respectively). When the cells were pretreated with 100 mM of H7, one of the potent protein kinase C inhibitors, the induction of mRNA encoding c-jun at 60 min. during the recovery phase was markedly suppressed (95% reduction of the levelos of c-jun mRNA at 60 min during the recovery without H-7). Pretreatment of the cardiac myocytes with 2 mM EGTA completely inhibited the increase in [Ca^<2+>] i during MI and [Ca^<2+>] i was kept at very lower level (184<plus-minus>26 nM at 30 min. during MI,n=3). This EGTA-pretreatment reduced the levels of c-jun mRNA by 42% (p<0.01, n=3) at 60 min. during recovery from MI of 30 min. as compared with those without EGTA.MAP kinase activity was also unchanged during MI,but significantly increased at 5,10,15 min during the recovery phase (3.0,4.1,3.4-fold increase as compared with the pre-MI controls, respecitively). Thus, these data suggest that IEG c-jun as well as MAP kinase may play significant roles in recovery of cardiac myocytes from a brief period of ischemia. This augmentation of c-jun expression may need the activation of protein kinase C,and to some extent, intracellular Ca^<2+>. Less
|
