Related Experiment Video
Updated: Aug 16, 2026
Cytosolic Calcium Measurements in Renal Epithelial Cells by Flow Cytometry
Published on: October 28, 2014
Tetracyclines reduce Na+/K+ pump capacity in Calu-3 human airway cells
12nd Department of Internal Medicine, School of Medicine, Nagoya University, Tsurumai-cho, Showa-ku, 466, Japan. itoyasu@tsuru.med.nagoya-u.ac.jp
Abstract:
We studied the effect of tetracyclines on the Na+/K+ pump activity in Calu-3, a human airway cell line. To estimate Na+/K+ pump capacity on the basolateral membrane, an ouabain-sensitive component of the short-circuit current (Isc) was measured in the presence of nystatin, an ionophore of Na+. The application of ouabain (1 mM) to the basolateral solution completely inhibited the Isc generated by adding nystatin (50 microM) to the apical solution. Tetracycline (TC), minocycline (MC), or demethylchlortetracycline (DC) at 0.5 mM applied to the apical but not to the basolateral solution also decreased the nystatin-induced Isc. Neither phlorizin- nor diphenylamine-2-carboxylic acid-sensitive Isc was affected by TC, MC, or DC. These results indicate that tetracyclines may permeate only through the apical membrane with the result that the Na+/K+ pump's capacity for Na+ extrusion should be suppressed without a decrease in Cl- transport.
Insights
Tetracyclines applied to the apical side of human airway cells suppress sodium-potassium pump (Na+/K+ pump) activity. This effect reduces sodium extrusion capacity without impacting chloride transport.
Area of Science:
- Cellular Physiology
- Pharmacology
- Respiratory Medicine
Background:
- The Na+/K+ pump is crucial for maintaining cellular ion balance in airway epithelial cells.
- Tetracyclines are antibiotics with potential off-target effects on cellular transport mechanisms.
Purpose of the Study:
- To investigate the impact of tetracyclines on Na+/K+ pump activity in human airway Calu-3 cells.
- To determine if tetracyclines affect ion transport across the apical or basolateral membranes.
Main Methods:
- Utilized short-circuit current (Isc) measurements in Calu-3 cells to assess Na+/K+ pump capacity.
- Applied nystatin (Na+ ionophore) and ouabain (Na+/K+ pump inhibitor) to evaluate pump function.
- Administered tetracycline, minocycline, and demethylchlortetracycline apically and basolaterally.
Main Results:
- Tetracyclines applied to the apical membrane significantly reduced the nystatin-induced Isc, indicating suppressed Na+/K+ pump activity.
- No significant effect on Isc was observed when tetracyclines were applied to the basolateral membrane.
- Tetracyclines did not affect phlorizin- or DPC-sensitive currents, suggesting specific action on the Na+/K+ pump.
Conclusions:
- Tetracyclines permeate the apical membrane of airway cells and inhibit Na+/K+ pump function.
- This inhibition reduces the cell's capacity for sodium extrusion.
- The observed effect on Na+/K+ pump activity occurs independently of changes in chloride transport.
More Related Videos
10:49Efficient Transcriptionally Controlled Plasmid Expression System for Investigation of the Stability of mRNA Transcripts in Primary Alveolar Epithelial Cells
Published on: March 6, 2020
09:04Fluorescence-Based Calcium Imaging in Primary Human Airway Epithelial Cultures Using Automated Cell Segmentation
Published on: May 22, 2026
Related Concept Videos
01:34ATP Driven Pumps II: P-type Pumps
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
01:30ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...