Contribution of sodium channel and sodium/hydrogen exchanger to sodium accumulation in the ischemic myocardium

Contribution of sodium channels and sodium/hydrogen exchangers (NHEs) to so dium accumulation during ischemia in the ischemic/reperfused heart was exam ined. Ischemia increased the myocardial sodium. Reperfusion elicited a furt her increase in the myocardial sodium, which was associated with little rec overy of the left ventricular developed pressure (LVDP) of the perfused hea rt. Treatment with tetrodotoxin or dimethylamirolide (DMA) dose-dependently attenuated the ischemia- and reperfusion-induced increase in myocardial so dium and enhanced the post-ischemic recovery of the LVDP. There was an inve rse relationship between the increase in myocardial sodium during ischemia and the post-ischemic recovery of the LVDP. The myocardial sodium accumulat ion during ischemia is mainly attributed to sodium influx through sodium ch annels and NHEs. (C) 2000 Elsevier Science Inc. All rights reserved.