The role of Na+/H+ exchange in ischemia-reperfusion.
In ischemia the cytosol of cardiomyocytes acidifies; this is reversed upon reperfusion. One of the major pH(i)-regulating transport systems involved is the Na+/H+ exchanger. Inhibitors of the Na+/H+ exchanger have been found to more effectively protect ischemic-reperfused myocardium when administered before and during ischemia than during reperfusion alone. It has been hypothesized that the protection provided by pre-ischemic administration is due to a reduction in Na+ and secondary Ca2+ influx. Under reperfusion conditions Na+/H/ exchange inhibition also seems protective since it prolongs intracellular acidosis which can prevent hypercontracture. In detail, however, the mechanisms by which Na+/H+ exchange inhibition provides protection in ischemic-reperfused myocardium are still not fully identified.
Piper
H M
HM
Physiologisches Institut, Justus-Liebig-Universität, Giessen, FRG.
Balser
C
C
Ladilov
Y V
YV
Schäfer
M
M
Siegmund
B
B
Ruiz-Meana
M
M
Garcia-Dorado
D
D
D000138:Acidosis / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007424:Intracellular Fluid / Q000378:metabolism; D017202:Myocardial Ischemia / Q000503:physiopathology* / Q000517:prevention & control; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology* / Q000517:prevention & control; D015427:Reperfusion Injury / Q000503:physiopathology* / Q000517:prevention & control; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000502:physiology*
D017923:Sodium-Hydrogen Exchangers; D012964:Sodium; D002118:Calcium