Abstract
In confluent primary cultures of dog tracheal epithelium, we tested whether Cl entry across the basolateral membrane is by cotransport with K. Two approaches were taken. First, we measured the inhibition of short-circuit current (I(sc)) by the K channel inhibitor, Ba2+. Consistent with Na-K-2Cl cotransport, maximal doses of Ba2+ inhibited five-sixths of I(sc) in tissues previously stimulated to secrete Cl; only two-thirds of I(sc) should be sensitive to Ba2+ if NaCl cotransport is the entry mechanism. Second, we measured basolateral 86Rb uptake and demonstrated inhibition by bumetanide, an inhibitor of Na-K-2Cl cotransport in other tissues. The degree of inhibition by bumetanide was consistent with the levels of Cl secretion measured as I(sc). Uptake of 86Rb was also reduced by removal of Na or Cl, and under these conditions Rb uptake was not further inhibited by bumetanide. These results suggest that the process responsible for Cl entry across the basolateral membrane of tracheal epithelium during Cl secretion is Na-K-2Cl rather than Na-Cl cotransport.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Lung Cellular and Molecular Physiology |
| Volume | 261 |
| Issue number | 4 5-2 |
| State | Published - 1991 |
| Externally published | Yes |
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Keywords
- barium ion
- bumetanide
- sodium-potassium-2-chloride cotransport
ASJC Scopus subject areas
- Cell Biology
- Physiology
- Pulmonary and Respiratory Medicine
Cite this
Potassium dependence of Na-Cl cotransport in dog tracheal epithelium. / Fong, P.; Chao, A. C.; Widdicombe, Jonathan.
In: American Journal of Physiology - Lung Cellular and Molecular Physiology, Vol. 261, No. 4 5-2, 1991.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Potassium dependence of Na-Cl cotransport in dog tracheal epithelium
AU - Fong, P.
AU - Chao, A. C.
AU - Widdicombe, Jonathan
PY - 1991
Y1 - 1991
N2 - In confluent primary cultures of dog tracheal epithelium, we tested whether Cl entry across the basolateral membrane is by cotransport with K. Two approaches were taken. First, we measured the inhibition of short-circuit current (I(sc)) by the K channel inhibitor, Ba2+. Consistent with Na-K-2Cl cotransport, maximal doses of Ba2+ inhibited five-sixths of I(sc) in tissues previously stimulated to secrete Cl; only two-thirds of I(sc) should be sensitive to Ba2+ if NaCl cotransport is the entry mechanism. Second, we measured basolateral 86Rb uptake and demonstrated inhibition by bumetanide, an inhibitor of Na-K-2Cl cotransport in other tissues. The degree of inhibition by bumetanide was consistent with the levels of Cl secretion measured as I(sc). Uptake of 86Rb was also reduced by removal of Na or Cl, and under these conditions Rb uptake was not further inhibited by bumetanide. These results suggest that the process responsible for Cl entry across the basolateral membrane of tracheal epithelium during Cl secretion is Na-K-2Cl rather than Na-Cl cotransport.
AB - In confluent primary cultures of dog tracheal epithelium, we tested whether Cl entry across the basolateral membrane is by cotransport with K. Two approaches were taken. First, we measured the inhibition of short-circuit current (I(sc)) by the K channel inhibitor, Ba2+. Consistent with Na-K-2Cl cotransport, maximal doses of Ba2+ inhibited five-sixths of I(sc) in tissues previously stimulated to secrete Cl; only two-thirds of I(sc) should be sensitive to Ba2+ if NaCl cotransport is the entry mechanism. Second, we measured basolateral 86Rb uptake and demonstrated inhibition by bumetanide, an inhibitor of Na-K-2Cl cotransport in other tissues. The degree of inhibition by bumetanide was consistent with the levels of Cl secretion measured as I(sc). Uptake of 86Rb was also reduced by removal of Na or Cl, and under these conditions Rb uptake was not further inhibited by bumetanide. These results suggest that the process responsible for Cl entry across the basolateral membrane of tracheal epithelium during Cl secretion is Na-K-2Cl rather than Na-Cl cotransport.
KW - barium ion
KW - bumetanide
KW - sodium-potassium-2-chloride cotransport
UR - http://www.scopus.com/inward/record.url?scp=0025991993&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025991993&partnerID=8YFLogxK
M3 - Article
C2 - 1928364
AN - SCOPUS:0025991993
VL - 261
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 4 5-2
ER -