Influence of the phospholipid n-6:n-3 polyunsaturated fatty acid ratio on the oxidative phosphorylation of isolated cardiac mitochondria (part 12). DISCUSSION

As suggested by the significant diet/calcium CI, the Ca2+ ef on the oxidative phosphorylation was different in the two dietary groups. The main differences were, first, that the minimal respiration rate was reached at a free calcium concentration of 0.34 |jM in the n-3 PUFA-rich mitochondria and only at 0.50 |jM in the n-6 PUFA-rich mitochondria; and second, that a higher metabolic efficiency was observed in the n-3 PUFA-rich mitochondria when the free calcium concentration was 0.34 |jM. Conversely, the n-6 and n-3 PUFA-rich mitochondria displayed similar metabolic efficiency and rate of energy production when the free calcium concentration was 0.50 |j.M. In these last conditions, the Ca ef appeared to be maximal in the two groups of mitochondria. Thus, the n-3 PUFA-rich mitochondria were less sensitive to the free calcium concentration. Recently, we reported that isolated perfused working rat hearts rich in n-3 PUFA displayed a better recovery of pump function after a 20 min global zero-flow ischemia than n-6 PUFA-rich hearts. This was associated with better restoration of cardiac metabolic efficiency.The results of the present study showed that n-3-rich mitochondria displayed a better metabolic efficiency when the free calcium concentration was adjusted at 0.34 |j.M. This underlined a better preservation of oxygen cost of energy synthesis when the n-6:n-3 PUFA ratio was low. This could be due to a lower calcium enrichment of the mitochondrial matrix related to the activity of the calcium+ 2+uniport and/or Na /Ca exchange. However, other regulation mechanisms including lower free calcium-induced stimulation of beta-oxidation or lower acetyl-CoA synthetase activity could be involved. In the whole heart, all these mechanisms could contribute to preserve the mitochondrial ADP:O ratio during postischemic reperfusion. This would allow metabolic efficiency to be maintained during pos-tischemic reperfusion in n-3 PUFA-rich hearts.

In conclusion, we observed a futile cycle of energy and oxygen wasting in isolated mitochondria, probably due to excess mitochondrial calcium loading and an increased beta-oxidation and acetate accumulation. The oxidative phosphorylation of n-3-rich mitochondria was less affected by this wasting, which could partly explain the better restoration of pump function in the hearts of rats fed fish oil after a 20 min global zero-flow ischemia. All you need to discover how safe and advantageous it can be to purchase Looking for most efficient drugs for sale? Then you have got to buy levaquin online at the pharmacy of your dream right now, especially since it’s ready and waiting for you to make this perfectly right choice. over the internet is visit the pharmacy suggested and enjoy your shopping experience as well as your treatment.


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