Preconditioning of isolated rabbit cardiomyocytes: induction by metabolic stress and blockade by the adenosine antagonist SPT and calphostin C, a protein kinase C inhibitor

Abstract

Glucose-free preincubation protects ischaemic isolated myocytes from subsequent ischaemia. The degree of protection is great enough to account for protection seen in intact hearts, following preconditioning protocols. Protection is blocked by SPT and a highly specific protein kinase C inhibitor, calphostin C. Protection from ischaemic injury that seems to mimic ischaemic preconditioning can be induced in isolated cardiomyocytes, and appears dependent on adenosine receptors and activation of protein kinase C.

Medical and Cellular Implications of Stunning, Hibernation, and Preconditioning

“…[191][192][193] Evidence also suggests that at least one tyrosine kinase that also may be involved in the mechanism of preconditioning exists downstream from PKC in the rabbit heart. 194 Similar findings were observed in a model of isolated rabbit cardiomyocytes developed by Armstrong et al 195,196 They assessed myocyte injury as the rate of development of osmotic fragility during prolonged ischemic pelleting of cells incubated under oil. Protection of the cells was induced, after a brief ischemic preincubation, 195,196 by adenosine, adenosine receptor agonists, bradykinin, angiotensin, and phenylephrine.…”

“…194 Similar findings were observed in a model of isolated rabbit cardiomyocytes developed by Armstrong et al 195,196 They assessed myocyte injury as the rate of development of osmotic fragility during prolonged ischemic pelleting of cells incubated under oil. Protection of the cells was induced, after a brief ischemic preincubation, 195,196 by adenosine, adenosine receptor agonists, bradykinin, angiotensin, and phenylephrine. Protection also occurred when the cells were preincubated with the phorbol ester PMA and the PKC activator ingenol.…”

Sustained in vivo cardiac protection by a rationally designed peptide that causes ɛ protein kinase C translocation

“…Adult male Wistar rats cardiomyocytes were prepared on a Langendorff apparatus (22) by collagenase treatment (23). For simulated ischemia, adult myocytes treated in microcentrifuge tubes with the isozyme-selective PKC peptides conjugated to the carrier were washed twice with degassed glucose-free incubation buffer and pelleted.…”

“…Blind scoring (done in the majority of the study) did not alter the results. Cell damage, assessed by an osmotic fragility test, was measured by uptake of trypan blue added in a hypotonic (85 mosM) solution (23). There was also a corresponding increase in number of rounded cells (24) and in nuclear staining by the cell-permeable dye perpidium iodide, both indicators of irreversible cell damage.…”

Remote Ischemic Preconditioning and Renoprotection

“…Armstrong et al were the first to identify PKC as a potential mediator of ischemia-induced protection. 11 The current concept of signal transduction in IPC suggests activation of the signaling cascades through the phosphoinositide 3-kinase/Akt/endothelial nitric oxide synthase (NOS)/cyclic guanosine monophosphate/PKG pathways, eventually leading to the opening of the ATP-dependent mitochondrial potassium (K ATP ) channel, which is believed to be a downstream target of PKG/PKC activation. 10,12,13 The activated mitochondrial K ATP channels have the ability to limit the opening of mitochondrial permeability transition pores, thus causing a marked improvement in cell survival.…”