Journal article
Intracellular potassium activities in canine tracheal epithelium
The American journal of physiology, Vol.245(3), pp.C248-254
09/1983
DOI: 10.1152/ajpcell.1983.245.3.C248
PMID: 6614158
Abstract
Canine tracheal epithelium secretes Cl- from the submucosal to the mucosal surface via an electrogenic transport process. To investigate the K+ transport mechanisms at the basolateral membrane, intracellular K+ activities were measured using conventional (KCl-filled) and K+-selective intracellular microelectrodes. When the rate of Cl- secretion was minimal, the intracellular K+ activity (a(cK+)) was 69 mM, a value twice the activity expected for an equilibrium distribution across the basolateral membrane. Following the addition of epinephrine (10-6 M) to the submucosal bathing solution, the rate of electrogenic Cl- secretion increased, as indicated by an increase in the short-circuit current, a decrease in transepithelial resistance, and a depolarization of the intracellular voltage. Despite the increase in transepithelial Cl- transport, a(cK+) was unaltered at 70 mM. These findings indicate that K+ is actively accumulated in the cell against its electrochemical gradient. The results also indicate that the electrochemical gradient for K+ at the basolateral membrane is more than sufficient to account for the estimated rate of K+ exit via an electrically conductive process. This conclusion is supported by the finding that submucosal barium, which partially blocks the basolateral K+ permeability, doubled the electrochemical driving force for K+ exit. These results, together with previous studies, provide compelling evidence for active transport of K+ into the cell via the Na+-K+ pump followed by the recycling of K+ back across a K+-conductive basolateral membrane. In addition, these results support previous suggestions that the K+ permeability of the basolateral membrane varies directly with the rate of transepithelial Cl- transport, thus maintaining a constant a(cK+) following stimulation of secretion.
Details
- Title: Subtitle
- Intracellular potassium activities in canine tracheal epithelium
- Creators
- Michael J Welsh
- Resource Type
- Journal article
- Publication Details
- The American journal of physiology, Vol.245(3), pp.C248-254
- DOI
- 10.1152/ajpcell.1983.245.3.C248
- PMID
- 6614158
- NLM abbreviation
- Am J Physiol
- ISSN
- 0002-9513
- eISSN
- 2163-5773
- Publisher
- American Physiological Society; United States
- Grant note
- HL-14388 / NHLBI NIH HHS
- Language
- English
- Date published
- 09/1983
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Fraternal Order of Eagles Diabetes Research Center; Neurosurgery; Internal Medicine
- Record Identifier
- 9984020703702771
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