Connexin 43 and ischemic preconditioning.
Connexin 43 (Cx43) is the essential protein to form hemichannels and gap junctions in the myocardium. The phosphorylation status of Cx43 which is regulated by a variety of protein kinases and phosphatases determines hemichannel and/or gap junction conductance and permeability. Gap junctions are involved in cell-cell coupling while hemichannels contribute to cardiomyocyte volume regulation. Cx43-formed channels are involved in ischemia/reperfusion injury, since blockade of a large portion of Cx43-formed channels attenuates ischemic hypercontracture, infarct development and post myocardial infarction remodeling. Ischemic preconditioning's protection also depends on functional Cx43-formed channels, since uncoupling of channels or genetic Cx43 deficiency abolishes infarct size reduction by ischemic preconditioning. The exact underlying mechanism(s) how Cx43 mediates protection remain to be established.
Schulz
Rainer
R
Institut für Pathophysiologie, Zentrum für Innere Medizin, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany. rainer_schulz@uni-essen.de
Heusch
Gerd
G
D000818:Animals; D002448:Cell Adhesion; D002463:Cell Membrane Permeability; D018031:Connexin 43 / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D019157:Ischemic Preconditioning, Myocardial; D015428:Myocardial Reperfusion Injury / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*
D018031:Connexin 43; D007473:Ion Channels