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Functional and structural changes of isolated rat parietal cells during membrane potential modulation
J Ostrowski1, D Jarosz, W Zych
1Department of Gastroenterology, Medical Center of Postgraduate Education, Warsaw, Poland.
Summary
Protonophore CCCP alters parietal cell membrane potential, translocating HCl from tubulovesicles to secretory canaliculi. This study investigates membrane recycling during gastric acid secretion.
Area of Science:
- Cell Biology
- Gastroenterology
- Physiology
Background:
- Parietal cells are crucial for gastric acid secretion.
- Membrane recycling is integral to parietal cell function.
- Earlier studies linked membrane potential to parietal cell membrane recycling.
Purpose of the Study:
- To investigate the role of membrane potential changes in parietal cell membrane recycling.
- To explore the translocation of HCl during gastric acid secretion.
- To elucidate the mechanisms of membrane recycling in vitro.
Main Methods:
- In vitro studies using isolated rat gastric glands.
- Measurement of 14C-aminopyrine accumulation for acid production.
- Acridine orange fluorescence for translocation.
- Assay of H+/K+-ATPase activity via pNPPase.
- Electron microscopy for cell morphology.
- Treatment with carbonyl cyanide m-chlorophenylhydrazone (CCCP) at varying pH.
Main Results:
- CCCP decreased aminopyrine accumulation at pH 6.6 but not pH 7.8.
- CCCP treatment altered H+/K+-ATPase distribution, increasing apical and decreasing tubulovesical activity.
- Electron microscopy revealed a shift from non-secreting to secreting parietal cell morphology.
- CCCP induced changes in acridine orange fluorescence, suggesting lumenal translocation.
Conclusions:
- Changes in parietal cell membrane potential induced by CCCP facilitate HCl translocation.
- Findings support the hypothesis of HCl movement from tubulovesicles to secretory canaliculi.
- Exact mechanisms of membrane recycling during parietal cell secretion require further investigation.