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Hydrogen peroxide inhibits Ca2+ efflux through plasma membrane Ca2+-ATPase in mouse parotid acinar cells
Intracellular Ca 2+ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study,...
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| Published in: | The Korean journal of physiology & pharmacology 2018, 22(2), , pp.215-223 |
|---|---|
| Main Authors: | , , , , , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Intracellular Ca
2+
mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide (H
2
O
2
) on cytosolic Ca
2+
accumulation in mouse parotid acinar cells. Intracellular Ca
2+
levels were slowly elevated when 1 mM H
2
O
2
was perfused in the presence of normal extracellular Ca
2+
. In a Ca
2+
-free medium, 1 mM H
2
O
2
still enhanced the intracellular Ca
2+
level. Ca
2+
entry tested using manganese quenching technique was not affected by perfusion of 1 mM H
2
O
2
. On the other hand, 10 mM H
2
O
2
induced more rapid Ca
2+
accumulation and facilitated Ca
2+
entry from extracellular fluid. Ca
2+
refill into intracellular Ca
2+
store and inositol 1,4,5-trisphosphate (1 µM)-induced Ca
2+
release from Ca
2+
store was not affected by 1 mM H
2
O
2
in permeabilized cells. Ca
2+
efflux through plasma membrane Ca
2+
-ATPase (PMCA) was markedly blocked by 1 mM H
2
O
2
in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected H
2
O
2
-induced Ca
2+
accumulation through PMCA inactivation. From the above results, we suggest that excessive production of H
2
O
2
under pathological conditions may lead to cytosolic Ca
2+
accumulation and that the primary mechanism of H
2
O
2
-induced Ca
2+
accumulation is likely to inhibit Ca
2+
efflux through PMCA rather than mobilize Ca
2+
ions from extracellular medium or intracellular stores in mouse parotid acinar cells. |
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| ISSN: | 1226-4512 2093-3827 |
| DOI: | 10.4196/kjpp.2018.22.2.215 |