Mitochondria and calcium ion transport

The uptake and release of calcium by heart mitochondria

“…The rapid uptake of Ca2+ by mitochondria has attracted much attention, partly because there are so many related effects, which include stimulated respiration, shifts of internal and external pH, shifts of redox state (Chance, 1965;Lehninger, 1970), delocalization of respiratory components (Vinogradov et al, 1972;Azzi et al, 1975) and anion uptakes (Harris & Berent, 1969;Brand et al, 1976). The practical question of physiological interest has been whether, and if so how, mitochondrial Ca2+ uptake supplements the activity of the sarcoplasmic reticulum in muscle, especially in the heart.…”

Microanalysis of Mitochondrial Granules. Microanalysis of Mitochondrial Granules in Bone Cells Incident to Experimental Tooth Movement

“…But, it seems that the size (200-500 A in diameter) of mitochondrial granules (28) in osteoblasts, osteocytes, and osteoclasts (Figs. 2-9) is no different from the size of mitochondrial granules seen in frozen sections (15).…”

“…However, Gay and Schraer (5), Termine (29) and Landis et al (12,13) suggest that an appraisal of ultrastructural features in bone cells and tissues will be very difficult, because potential artifacts may be introduced into the cellular components and the mineral phase of bone as a result of contact with aqueous solvents during its preparation for electron microscopy (13,14,15,20). But, it seems that the size (200-500 A in diameter) of mitochondrial granules (28) in osteoblasts, osteocytes, and osteoclasts (Figs.…”

“…Lehninger (15) says "although this working hypothesis has obvious points of weakness, particularly with regard to the mechanism by which the micro-packets leave the mitochondria, it does account in a chemically satisfactory way for the fact that potential for calcification was a broadly distributed property of cells and that calcium phosphate granules appear in the mitochondria during active calcification or decalcification". It is quite natural that mitochondrial granules should be seen in osteoblasts and in young osteocytes which were given a stimulus (the teeth were moved experimentally) and that Ca-K, P-K, and Os-M should be detected in the granules.…”

Reverse mode Na+/Ca2+ exchange-induced cell dehydration as a primary mechanism for cell pathology

“…It is known that Na + /K + pump, with the function of controlling intracellular ionic homeostasis, works in electrogenic regime, generates the metabolic component of membrane potential [2][3][4] and has a crucial role in cell volume regulation [5,6]. The activation of Na + /K + pump leads to generation of water efflux from the cells by a) push out of 3Na + and uptake of 2K + and b) release of H 2 O in cytoplasm (42 H 2 O for one molecule glucose oxidation) as a result of activation of intracellular oxidative phosphorylation [7]. Such a Na + /K + pump-induced water efflux has a great physiological meaning as it balances the osmotic water uptake [5] by cell and inactivates Na + and Ca 2+ inward currents through the membrane [8,9].…”