Effects of NH4Cl and dimethylamine on Cl- fluxes in resting and stimulated rat submandibular acinar cells
Transmembrane movements of K+ and Cl- in salivary acinar cells are important in the formation of saliva, and may be affected by changes in intracellular pH (pHi). Exposure to NH4Cl increases pHi transiently, but NH4+ may have effects independent of pHi. To investigate how Cl- transport may be altere...
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Published in | The American journal of physiology Vol. 263; no. 4 Pt 1; p. G558 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.10.1992
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Subjects | |
Online Access | Get more information |
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Summary: | Transmembrane movements of K+ and Cl- in salivary acinar cells are important in the formation of saliva, and may be affected by changes in intracellular pH (pHi). Exposure to NH4Cl increases pHi transiently, but NH4+ may have effects independent of pHi. To investigate how Cl- transport may be altered under these conditions, rat submandibular acini were exposed to NH4Cl, and transmembrane Cl- transport was studied with 36Cl-. NH4Cl increased intracellular Cl- in these cells. The initial phase of this increase was partially HCO(3-)-dependent and was inhibited by 1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), while the sustained phase was inhibited by 0.1 mM bumetanide. NH4Cl also inhibited acetylcholine-induced Cl- efflux from tracer preloaded cells. Changes in pH did not always correlate in time or extent with those of Cl- transport. We conclude that 1) exposure to NH4Cl increases Cl-uptake primarily by a bumetanide-sensitive transport system that did not reach steady state during the experiment, 2) exposure to NH4Cl also stimulates Cl- uptake by a DIDS-sensitive mechanism, and 3) only the latter is pHi sensitive. |
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ISSN: | 0002-9513 |
DOI: | 10.1152/ajpgi.1992.263.4.G558 |