| 11841804 |
Camello-Almaraz C, Salido GM, Pariente JA, Camello PJ: Role of mitochondria in Ca (2+) oscillations and shape of Ca (2+) signals in pancreatic acinar cells. Biochem Pharmacol. 2002 Jan 15;63(2):283-92.
We studied the role of mitochondria in Ca (2+) signals in fura-2 loaded exocrine pancreatic acinar cells. Mitochondrial depolarization in response to carbonylcyanide-p-tryfluoromethoxyphenyl hydrazone or rotenone (assessed by confocal microscopy using rhodamine-123) induced a partial but statistically significant reduction in the decay of Ca (2+) signals under different experimental conditions. Spreading of Ca (2+) waves evoked by the pancreatic secretagogue cholecystokinin cholecystokinin octapeptide was accelerated by mitochondrial inhibitors, whereas the cytosolic Ca (2+) concentration ([Ca (2+)](i)) oscillations in response to physiological levels of this hormone were suppressed by rotenone and carbonylcyanide-p-tryfluoromethoxyphenyl hydrazone. Oligomycin, an inhibitor of mitochondrial ATP synthase, did no affect either propagation of calcium waves nor [Ca (2+)](i) oscillations. Individual mitochondria of rhod-2 loaded acinar cells showed heterogeneous matrix Ca (2+) concentration increases in response to oscillatory and maximal levels of cholecystokinin octapeptide. On the other hand, using Ba (2+) for unequivocal study of capacitative calcium entry we found that mitochondrial inhibitors did not affect this process. Our results show that although the role of mitochondria as a Ca (2+) clearing system in exocrine cells is quantitatively secondary, they play an essential role in the spatial propagation of Ca (2+) waves and in the development of [Ca (2+)](i) oscillations. |
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