On the properties of calcium-induced permeability transition in neonatal heart mitochondria

    loading  Checking for direct PDF access through Ovid

Abstract

Permeability transition was examined in heart mitochondria isolated from neonate rats. We found that these mitochondria were more susceptible to Ca2+-induced membrane leakiness than mitochondria from adult rats. In K+ containing medium, at 25 °C, mitochondria were unable to accumulate Ca2+. Conversely, in Na+ containing medium, mitochondria accumulated effectively Ca2+. At 15 °C mitochondria accumulated Ca2+ regardless of the presence of K+. Kinetics of Ca2+ accumulation showed a similar Vmax as that of adult mitochondria. Lipid milieu of inner membrane contained more unsaturated fatty acids than adult mitochondria. Aconitase inhibition and high thiobarbituric acid-reactive substances (TBARS) indicate that oxidative stress caused mitochondrial damage. In addition, proteomics analysis showed that there is a considerable diminution of succinate dehydrogenase C and subunit 4 of cytochrome oxidase in neonate mitochondria. Our proposal is that dysfunction of the respiratory chain makes neonate mitochondria more susceptible to damage by oxidative stress.

Related Topics

    loading  Loading Related Articles