Submitted on December 8, 2005
Accepted on January 24, 2006
Sex-differences in myocardial infarct size are abolished by sarcolemmal KATP channel blockade in rat
Micah S Johnson1, Russell L Moore1*, and David A Brown1
1 Integrative Physiology, University of Colorado at Boulder, Boulder, CO, USA
* To whom correspondence should be addressed. E-mail: russell.moore{at}colorado.edu.
This study was conducted to examine the relationship between myocardial ATP-sensitive potassium (KATP) channels and sex-differences in myocardial infarct size following in vitro ischemia/reperfusion (I/R). Hearts from adult male and female Sprague-Dawley rats were excised and exposed to a 1h/2h I/R protocol on a modified Langendorff apparatus. Hearts from female rats showed significantly smaller infarct sizes than hearts from males (23 ± 4 versus 40 ± 5 % of the zone at risk, respectively; P < 0.05). Administration of HMR 1098, a sarcolemmal KATP channel blocker, abolished the sex difference in infarct size (42 ± 4 versus 45 ± 5 % of the zone at risk in hearts from female and male rats, respectively, P = NS). Further experiments showed that blocking the KATP channels in ischemia, and not reperfusion, was sufficient to increase infarct size in female rats. These data demonstrate that sarcolemmal KATP channels are centrally involved in mechanisms that underlie sex-differences in the susceptibility of the intact heart to I/R injury.
