Acute memory phase of sevoflurane preconditioning is associated with sustained translocation of protein kinase C-alpha and epsilon, but not delta, in isolated guinea pig hearts.
OBJECTIVE
Anaesthetic preconditioning (APC) exerts cardioprotective effects by reducing infarct size and improving recovery of contractile function after ischaemia-reperfusion. The interval between brief exposure to volatile anaesthetic and sustained ischaemia, the acute memory phase, is dependent on intracellular signalling mediating this cardioprotection. Intramyocyte translocation of protein kinase C (PKC) is known to be a key mediator in APC. We examined the relationship between the time frame of the acute memory phase of sevoflurane preconditioning and intramyocyte translocation of PKC-alpha, delta and epsilon to the particulate fraction.


METHODS
Isolated perfused guinea pig hearts were subjected to 30 min ischaemia and 120 min reperfusion. APC was elicited with one minimum alveolar concentration sevoflurane for 10 min. Washout times of 10, 30, 60 and 90 min were studied. Contractile recovery was assessed by monitoring left ventricular developed pressures. Infarct size was determined by triphenyltetrazolium chloride staining. Translocation of PKC was examined by western blot analysis.


RESULTS
After ischaemia-reperfusion, left ventricular developed pressure recovered to a greater degree with APC compared with control for washout times of 10 and 30 min, but not 60 and 90 min. Similarly, infarct size was reduced for washout times of 10 and 30 min, but not 60 and 90 min. Sustained translocation of PKC-alpha and epsilon, but not delta, was associated with the time frame of the acute memory phase.


CONCLUSIONS
The acute memory phase of sevoflurane preconditioning is limited to less than 60 min. Sustained translocation of PKC-alpha and epsilon, but not delta, correlates with this acute memory phase of sevoflurane preconditioning.
Okusa
Chika
C
Department of Anaesthesiology, Osaka Dental University, Osaka, Japan.
Miyamae
Masami
M
Sugioka
Shingo
S
Kaneda
Kazuhiro
K
Inamura
Yoshitaka
Y
Onishi
Anna
A
Domae
Naochika
N
Kotani
Junichiro
J
Figueredo
Vincent M
VM
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D051571:Protein Kinase C-alpha / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000378:metabolism; D051744:Protein Kinase C-epsilon / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D000077149:Sevoflurane; D013997:Time Factors
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon