In another study, although transgenic mice models overexpressing NHE1 had no significant effect on cardiac function, intracellular pH, intracellular Na+, and ischemia-reperfusion injury, NHE1 inhibition with cariporide prior to the development of ischemia prevented the accumulation of Na+ and Ca2+ and decreased ischemia-reperfusion injury, showing that baseline NHE1 activity was not the rate-limiting step [89]. This evidence concerns the gene SLC9A1 and ischemia.