Issue Archive

Inhibitors of Na~(+)/ H~(+)and Na ~(+)/ Ca~(2+)exchange depress intracellular calcium elevation induced by ischemia/reperf union in rat cardiacmyocytes

DONG Jian Wen

aboratory of Hypoxic Cardiovascular Physiology，Shanghai Institutes for Biological Science ，Chinese Academy of Science，Shanghai

Abstract

An increase in cytosolic free calcium has been shown to occur during ischemia in perfused hearts and plays a pivotal role in ischemia/ reperfusion injury.The objective‘this study was to investigate the contributions‘Na`/H `exchange and M~(+)/cat+exchange to changes in intracellular calcium([Ca~(2+)];) during simulated ischemia and reperfusion in quiescent isolated rat cardiac myocytes.[Ca 2+]; was measured by laser confocal microscope using the fluorescent indicator Huo 3 and expressed as the corrected intensity‘Huo 3 fluorescence.[ca~(2+)]1 increased to 140. 3士13.0%(P(0.05preischemic control 100%)after 5 min simulated isthe mia，and remained at high level of 142.8士15.5%(P(0. 05) after the following 15 min reperfusion.The increase in[ca~(2+)]1 during simulated ischemia and reperfusion was suppressed by 100 umol/ L amiloride(inhibitor of M~(+)/H` exchanger)，5 mmol/ L NiCl2(inhibitor of Na~(+)/cat+exchanger) and calcium-free solution;[cat+]1 was 101.4士16. 3%，110.4士11.1%and 107.1士10.8%，respectively，after 5 min simulated ischemia，and 97.8士14.3%，106.2士14.5%and 106.6士15.7%，respectively，after 15 minre on .Compared with control cells，the amplitude of spontaneous calcium oscillation was lessened in cells treated with(rfree perfusion and MCl2 during reperfusion .In addition，no calcium oscillation was observed in cells pretreated with .These results suggest that MH+exchange and Na ca~(2+)exchange are activated during simulated ischemia in isolated quiescent cardiac myocytes，leading to the elevation of[Ca~(2+)]; induced by simulated ischemia and reperfusion.

Key words: cardiac myocytes;ischemia/ reperfusion;Calcium;Na+/H+exchanger;sodium- calcium exchanger

Received: 　　Accepted:

Corresponding author: 　　E-mail:

Citing This Article：

DONG Jian Wen. Inhibitors of Na~(+)/ H~(+)and Na ~(+)/ Ca~(2+)exchange depress intracellular calcium elevation induced by ischemia/reperf union in rat cardiacmyocytes . Acta Physiol Sin 2003; 55 (3): (in Chinese with English abstract).