Key result
Administration of the sarcolemmal K(ATP) channel blocker HMR-1098 abolished baseline sex differences in myocardial infarct size between female and male rat hearts (42% vs 45%, P=not significant).
Why the study?
Does sarcolemmal K(ATP) channel blockade abolish sex differences in myocardial infarct size after ischemia-reperfusion injury in rat hearts?
Does sarcolemmal K(ATP) channel blockade abolish sex differences in myocardial infarct size after ischemia-reperfusion injury in rat hearts?
Sarcolemmal K(ATP) channels are centrally involved in the mechanisms underlying sex differences in susceptibility to myocardial ischemia-reperfusion injury.
Sarcolemmal KATP blockade abolishes sex differences in rat infarct size; leaves open translation to human ischemia-reperfusion injury.
This study was conducted to examine the relationship between myocardial ATP-sensitive potassium (K(ATP)) channels and sex differences in myocardial infarct size after in vitro ischemia-reperfusion (I/R). Hearts from adult male and female Sprague-Dawley rats were excised and exposed to an I/R protocol (1 h of ischemia, followed by 2 h of reperfusion) on a modified Langendorff apparatus. Hearts from female rats showed significantly smaller infarct sizes than hearts from males (23 +/- 4 vs. 40 +/- 5% of the zone at risk, respectively; P < 0.05). Administration of HMR-1098, a sarcolemmal K(ATP) channel blocker, abolished the sex difference in infarct size (42 +/- 4 vs. 45 +/- 5% of the zone at risk in hearts from female and male rats, respectively; P = not significant). Further experiments showed that blocking the K(ATP) channels in ischemia, and not reperfusion, was sufficient to increase infarct size in female rats. These data demonstrate that sarcolemmal K(ATP) channels are centrally involved in mechanisms that underlie sex differences in the susceptibility of the intact heart to I/R injury.
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Johnson et al. (2006) studied Myocardial ischemia-reperfusion injury. HMR-1098 (sarcolemmal K(ATP) channel blocker) vs. Baseline (no HMR-1098) / Male rats was evaluated on Myocardial infarct size (% of the zone at risk) in female vs male rats (p=not significant). Administration of the sarcolemmal K(ATP) channel blocker HMR-1098 abolished baseline sex differences in myocardial infarct size between female and male rat hearts (42% vs 45%, P=not significant).
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