Propofol-induced activation of protein kinase C isoforms in adult rat ventricular myocytes.
BACKGROUND
Myocardial protection by anesthetics is known to involve activation of protein kinase C (PKC). The authors' objective was to identify the PKC isoforms activated by propofol in rat ventricular myocytes. They also assessed the intracellular location of individual PKC isoforms before and after treatment with propofol.


METHODS
Freshly isolated ventricular myocytes were obtained from adult rat hearts. Immunoblot analysis of cardiomyocyte subcellular fractions was used to assess translocation of individual PKC isoforms before and after exposure to propofol. An enzyme-linked immunosorbent assay kit was used for measuring PKC activity. Immunocytochemistry and confocal microscopy were used to visualize the intracellular location of the individual PKC isoforms.


RESULTS
Under baseline conditions, PKC-alpha, PKC-delta, and PKC-zeta were associated with both the cytosolic and membrane fractions, whereas PKC-epsilon was exclusively located in the cytosolic fraction. Propofol (10 microM) caused translocation of PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta from cytosolic to membrane fraction and increased total PKC activity (211 +/- 17% of baseline; P = 0.003) in a dose-dependent manner. Immunocytochemical localization of the individual PKC isoforms demonstrated that propofol caused translocation of PKC-alpha to the intercalated discs and z-lines; PKC-delta to the perinuclear region; PKC-epsilon to sites associated with the z-lines, intercalated discs, and the sarcolemma; and PKC-zeta to the nucleus.


CONCLUSIONS
These results demonstrate that propofol causes an increase in PKC activity in rat ventricular myocytes. Propofol stimulates translocation of PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta to distinct intracellular sites in cardiomyocytes. This may be a fundamentally important cellular mechanism of anesthesia-induced myocardial protection in the setting of ischemia-reperfusion injury.
Wickley
Peter J
PJ
Kent State University, Kent, Ohio, USA.
Ding
Xueqin
X
Murray
Paul A
PA
Damron
Derek S
DS
D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002846:Chromatography, Affinity; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015151:Immunoblotting; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism; D018613:Microscopy, Confocal; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D015742:Propofol / Q000494:pharmacology*; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology
D018686:Anesthetics, Intravenous; D007527:Isoenzymes; D011493:Protein Kinase C; D015742:Propofol