Role of sarcoplasmic reticulum in the contractile dysfunction during myocardial ischaemia and reperfusion.

In the myocardium, the sarcoplasmic reticulum (SR) plays an essential role in the regulation of cytosolic free Ca2+ ion concentration and, hence, in the contraction-relaxation cycle. The aim of this review is to summarize the role of the SR, particularly the main SR Ca2+ transport proteins, Ca2+-ATPase pump and Ca2+ release channel (ryanodine receptor), in contractile impairment during ischaemia and reperfusion. As suggested by most studies, SR dysfunction may contribute to contractile failure during ischaemia. However, SR function is largely restored during reperfusion and minor changes are unlikely to explain the severe postischaemic contractile dysfunction.