On the properties of calcium-induced permeability transition in neonatal heart mitochondria |
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Authors: | Pavón Natalia Gallardo Juan Carlos Hernández-Esquivel Luz María El-Hafidi Mohammed Buelna-Chontal Mabel Zazueta Cecilia Rodríguez-Enríquez Sara Chávez Edmundo |
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Institution: | Departamento de Bioquímica, Instituto Nacional de Cardiología, Ignacio Chávez, Juan Badiano # 1, Tlalpam, Mexico, DF, 014080, Mexico. |
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Abstract: | Permeability transition was examined in heart mitochondria isolated from neonate rats. We found that these mitochondria were more susceptible to Ca(2+)-induced membrane leakiness than mitochondria from adult rats. In K(+) containing medium, at 25?°C, mitochondria were unable to accumulate Ca(2+). Conversely, in Na(+) containing medium, mitochondria accumulated effectively Ca(2+). At 15?°C mitochondria accumulated Ca(2+) regardless of the presence of K(+). Kinetics of Ca(2+) 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. |
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