[Cellular recovery after ischemia: physiopathologic aspects].

Myocytes that have survived a period of transient ischemia may present prolonged alterations of cellular function, detectable during several days. The early period of postischemic reperfusion is characterized by restoration of ion homeostasis mediated by rapid resumption of function of ion pumps (Na+/K(+)-ATPase, Ca(2+)-ATPase) and transsarcolemmal ion exchange mechanisms (H+/Na+, Na+/Ca2+ exchangers). There is experimental evidence that cellular injury may be enhanced during the initial seconds or minutes of reperfusion, depending on the conditions of reperfusion. During the late phase of reperfusion mRNA expression of a number of key proteins of myocyte function is altered. The pattern of gene expression during reperfusion exhibits features of cellular adaptation and/or dedifferentiation in addition to cell repair.