Mitochondrial big conductance KCa channel and cardioprotection in infant rabbit heart

作者：Shi Yang^*; Jiang Ming Tao; Su Jidong; Hutchins William; Konorev Eugene; Baker John E

来源：Journal of Cardiovascular Pharmacology, 2007, 50(5): 497-502.

DOI：10.1097/fjc.0b013e318137991d

• hypoxia
• mitoBKCa channels
• cardioprotection
• NS1619
• Paxilline
• ischemia-reperfusion

Chronic hypoxia increases resistance to myocardial ischemia in infants. Activation of the mitochondrial big conductance Ca2+-sensitive K channel (mitoBKCa) has been shown to be protective in adult hearts; however, its role in infant hearts is unknown. Hearts from normoxic or hypoxic infant rabbits were perfused with a mitoKCa opener, NS1619, or blocker Paxilline before ischemia and reperfusion. Hypoxic hearts were more resistant to ischemia than normoxic hearts as manifested by a reduction in infarct size (9 +/- 5% versus 14 +/- 5%) and an increase in recovery of left ventricular developed pressure (LVDP) (69 +/- 7% versus 51 +/- 2%). NS1619 decreased infarct size in normoxic hearts from 14 +/- 5% to 10 +/- 5% and increased recovery of LVDP from 51 +/- 2% to 65 +/- 4%, but it had no effect on hypoxic hearts. Paxilline did not affect normoxic or hypoxic hearts. Activation of mitoBKCa protects normoxic infant rabbit hearts; however, cardioprotection by chronic hypoxia in infant rabbits does not appear involve mitoBKCa.

• 出版日期2007-11