Protein kinase C translocation and Src protein tyrosine kinase activation mediate isoflurane-induced preconditioning in vivo: potential downstream targets of mitochondrial adenosine triphosphate-sensitive potassium channels and reactive oxygen species.
BACKGROUND
The authors tested the hypotheses that protein kinase C (PKC)-specific isoform translocation and Src protein tyrosine kinase (PTK) activation play important roles in isoflurane-induced preconditioning in vivo.


METHODS
Rats (n = 125) instrumented for measurement of hemodynamics underwent 30 min of coronary artery occlusion followed by 2 h of reperfusion and received 0.9% saline (control); PKC inhibitors chelerythrine (5 mg/kg), rottlerin (0.3 mg/kg), or PKC-epsilonV1-2 peptide (1 mg/kg); PTK inhibitors lavendustin A (1 mg/kg) or 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1; 1 mg/kg); mitochondrial adenosine triphosphate-sensitive potassium channel antagonist 5-hydroxydecanote (10 mg/kg); or reactive oxygen species scavenger N-acetylcysteine (150 mg/kg) in the absence and presence of a 30-min exposure to isoflurane (1.0 minimum alveolar concentration) in separate groups. Isoflurane was discontinued 15 min before coronary occlusion (memory period). Infarct size was determined using triphenyltetrazolium staining. Immunohistochemistry and confocal microscopic imaging were performed to examine PKC translocation in separate groups of rats.


RESULTS
Isoflurane significantly (P < 0.05) reduced infarct size (40 +/- 3% [n = 13]) as compared with control experiments (58 +/- 2% [n = 12]). Chelerythrine, rottlerin, PKC-epsilonV1-2 peptide, lavendustin A, PP1, 5-hydroxydecanote, and N-acetylcysteine abolished the anti-ischemic actions of isoflurane (58 +/- 2% [n = 8], 50 +/- 3% [n = 9], 53 +/- 2% [n = 9], 59 +/- 3% [n = 6], 57 +/- 3% [n = 7], 60 +/- 3% [n = 7], and 53 +/- 3% [n = 6], respectively). Isoflurane stimulated translocation of the delta and epsilon isoforms of PKC to sarcolemmal and mitochondrial membranes, respectively.


CONCLUSIONS
Protein kinase C-delta, PKC-epsilon, and Src PTK mediate isoflurane-induced preconditioning in the intact rat heart. Opening of mitochondrial adenosine triphosphate-sensitive potassium channels and generation of reactive oxygen species are upstream events of PKC activation in this signal transduction process.
Ludwig
Lynda M
LM
Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226, USA.
Weihrauch
Dorothee
D
Kersten
Judy R
JR
Pagel
Paul S
PS
Warltier
David C
DC
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D007527:Isoenzymes / Q000378:metabolism; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D009203:Myocardial Infarction / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D015221:Potassium Channels; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
D018685:Anesthetics, Inhalation; D007527:Isoenzymes; D008565:Membrane Proteins; D015221:Potassium Channels; D017382:Reactive Oxygen Species; C117780:mitochondrial K(ATP) channel; D007530:Isoflurane; D019061:src-Family Kinases; D011493:Protein Kinase C