Sublethal simulated ischemia promotes delayed resistance against ischemia via ATP-sensitive (K+) channels in murine myocytes: role of PKC and iNOS.
In this study, we examined whether sublethal simulated ischemia (SSI) induces delayed cellular protection in mouse cardiac myocytes, and whether the delayed cellular protection depends on the activation of protein kinase C-epsilon (PKC-epsilon), inducible nitric oxide synthase (iNOS), and ATP-sensitive K(+) (K(ATP)) channels against subsequent sustained simulated ischemia (SI). The following groups of mouse cardiac myocytes were studied: (a) SI: incubation with SI buffer for 1 h; (b) SSI: incubation with SSI buffer for 30 min; (c) SSI + PKC inhibitor, chelerythrine chloride (CCl): SSI and 1 micro M CCl; (d) SSI + iNOS inhibitor, S-methylthiourea (SMT): SSI and 100 nM SMT; (e) SSI + K(ATP) channel blocker, glibenclamide (Glb): SSI and 50 micro M Glb; (f) SSI + mitochondrial K(ATP) channel blocker, 5-hydroxydecanoate (5-HD): SSI and 50 micro M 5-HD. The release of lactate dehydrogenase into the medium and the amount remaining in the cells was measured, and A(1) adenosine receptor, PKC-epsilon, and iNOS were detected through western blot analysis. The delayed cellular protection acquired due to SSI showed a decreased release of lactate dehydrogenase (%) from 46.51 +/- 1.60 to 37.00 +/- 1.34 (p < 0.001) and was blocked by CCl (47.08 +/- 0.95), SMT (48.08 +/- 1.18), Glb (45.88 +/- 1.31), and 5-HD (47.20 +/- 1.56). Simultaneously, SSI-induced up-regulation of A(1) adenosine receptor, PKC-epsilon, iNOS, and opening of both membrane and mitochondrial K(ATP) channels also was observed compared with controls.
Nayeem
Mohammed A
MA
DIR ETP LPC MEM, National Institute of Environment and Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA. nayeem@niehs.nih.gov
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D002478:Cells, Cultured; D003652:Decanoic Acids / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006880:Hydroxy Acids / Q000494:pharmacology; D019194:Ischemic Preconditioning; D007550:Isothiuronium / Q000031:analogs & derivatives* / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D017202:Myocardial Ischemia / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D043682:Receptor, Adenosine A1 / Q000378:metabolism
D000889:Anti-Arrhythmia Agents; D003652:Decanoic Acids; D004791:Enzyme Inhibitors; D006880:Hydroxy Acids; D024661:Potassium Channels, Inwardly Rectifying; D043682:Receptor, Adenosine A1; D007550:Isothiuronium; C052853:5-hydroxydecanoic acid; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C497256:Prkce protein, mouse; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; C027744:S-methylisothiopseudouronium; D005905:Glyburide