Calcium accumulating ability of mitochondria from bovine coronary artery. Comparison with aortic mitochondria.
The calcium accumulating ability of mitochondria isolated both from bovine coronary artery and aorta was investigated. Coronary artery and aorta were pretreated with 0.1% collagenase. Cytochrome c oxidase activities of mitochondria isolated from coronary artery and aorta showed 25-fold and 19-fold increases, respectively, as compared with those of each homogenate, whereas NADPH-cytochrome c reductase, potassium-phosphatase and Na+-K+ ATPase activities increased less than 2-fold. This suggests that the isolation procedure is capable of obtaining a subcellular fraction highly enriched with mitochondria. Mitochondrial calcium uptake activity of the coronary artery was approximately 250 nmoles Ca2+/mg protein/10 min, and was markedly depressed with metabolic inhibitors such as NaN3, ruthenium red and 2,4-dinitrophenol. Calcium uptake activity of bovine aortic mitochondria showed similar activity and a similar trend in sensitivity to metabolic inhibitors. By contrast, the onset of the calcium binding reaction of the aortic mitochondria was slower and the azide-sensitivity of the mitochondria to magnesium ATPase activity was lower than those for coronary artery mitochondria. The present study has provided a method for isolation of mitochondria with a high capacity of calcium uptake activity, which may prove meaningful for future physiological and pharmacological evaluation of mitochondrial calcium accumulation in vascular smooth muscle.
Takeo
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S
Sakanashi
M
M
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000648:ultrastructure*; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D003331:Coronary Vessels / Q000648:ultrastructure*; D003470:Culture Media; D003576:Electron Transport Complex IV / Q000378:metabolism; D066298:In Vitro Techniques; D003012:Microbial Collagenase / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
D003470:Culture Media; D003576:Electron Transport Complex IV; D000469:Alkaline Phosphatase; D003012:Microbial Collagenase; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium