Pleural surface fluorescence measurement of Na+ and Cl- transport across the air space-capillary barrier.
We developed a pleural surface fluorescence method to measure Na(+) and Cl(-) transport in perfused mouse lungs. The air space was filled with aqueous fluid containing membrane-impermeant fluorescent indicators of Cl(-) (lucigenin) or Na(+) (Sodium Green). After instillation of a Cl(-)-free solution into the air space, an increase in perfusate Cl(-) concentration from 0 to 30 mM produced a decrease in surface lucigenin fluorescence (6.5%/min) corresponding to Cl(-) influx of 1.0 mM/min. Cl(-) influx was increased to 2.1 +/- 0.3 mM/min by forskolin, and the increase was inhibited by glibenclamide. cAMP-stimulated Cl(-) influx was decreased by 57% in CFTR null mice. After instillation of a Na(+)-free solution into the air space, an increase in perfusate Na(+) concentration from 0 to 30 mM gave increased Sodium Green fluorescence (Na(+) influx of 1.2 mM/min), which increased approximately fivefold after cAMP agonists. Cl(-) and Na(+) transport were not affected in lungs from mice lacking aquaporins AQP1 or AQP5. Our results establish a pleural surface fluorescence method to measure unidirectional Cl(-) and Na(+) flux in intact lung and provide evidence for cAMP-stimulated transcellular Cl(-) and Na(+) transport.
Jiang
Jinjun
J
Department of Medicine, Cardiovascular Research Institute, University of California, San Francisco, 94143 - 0521, USA.
Song
Yuanlin
Y
Bai
Chunxue
C
Koller
Beverly H
BH
Matthay
Michael A
MA
Verkman
A S
AS
D000166:Acridines; D000818:Animals; D051398:Aquaporin 1; D051402:Aquaporin 5; D020346:Aquaporins / Q000235:genetics; D001692:Biological Transport / Q000187:drug effects; D015824:Blood-Air Barrier / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics; D005456:Fluorescent Dyes; D005905:Glyburide / Q000494:pharmacology; D066298:In Vitro Techniques; D008565:Membrane Proteins; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout / Q000235:genetics; D009930:Organic Chemicals; D010994:Pleura / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D000166:Acridines; C496021:Aqp1 protein, mouse; C496038:Aqp5 protein, mouse; D051402:Aquaporin 5; D020346:Aquaporins; D002352:Carrier Proteins; D002712:Chlorides; D005456:Fluorescent Dyes; D008565:Membrane Proteins; D009930:Organic Chemicals; C098118:sodium green; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D051398:Aquaporin 1; D005576:Colforsin; C033472:10,10'-dimethyl-9,9'-biacridinium; D012964:Sodium; D000242:Cyclic AMP; D005905:Glyburide