Anion exchange in type II pneumocytes freshly isolated from adult guinea-pig lung.
We have studied chloride influx and efflux in a highly purified preparation of type II cells freshly isolated from adult guinea-pig lung using 36Cl-. Chloride uptake was time-dependent, saturable (Km < 10 mM) and was inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS; Ki approximately 80 microM). In the absence of external chloride (substituted by gluconate), 36Cl- uptake exhibited an overshoot above equilibrium. The rate of 36Cl- entry was strongly inhibited by addition of external nitrate; sulphate was a weaker inhibitor. 36Cl- efflux was stimulated by external bromide > bicarbonate > or = chloride > or = citrate; and was inhibited by propionate > acetate > oxalate. Although the "chloride channel blocker" 4-nitro-2-(3-phenylpropylamino)benzoate (0.14 mM) caused an inhibition, 36Cl- influx did not appear to be electrogenic. These data are compatible with the existence of a substantial electroneutral anion-exchange pathway for chloride transport in freshly isolated adult type II pneumocytes.
Kemp
P J
PJ
Department of Child Health, Ninewells Hospital and Medical School, University of Dundee, UK.
Boyd
C A
CA
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000818:Animals; D000838:Anions; D001639:Bicarbonates / Q000494:pharmacology; D001965:Bromides / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors; D002712:Chlorides / Q000378:metabolism* / Q000494:pharmacology; D002713:Chlorine; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D005942:Gluconates / Q000494:pharmacology; D006168:Guinea Pigs; D007700:Kinetics; D008168:Lung / Q000166:cytology* / Q000378:metabolism*; D009566:Nitrates / Q000494:pharmacology; D009579:Nitrobenzoates / Q000494:pharmacology; D011868:Radioisotopes; D013431:Sulfates / Q000494:pharmacology
D000838:Anions; D001639:Bicarbonates; D001965:Bromides; D018118:Chloride Channels; D002712:Chlorides; D002951:Citrates; D005942:Gluconates; D009566:Nitrates; D009579:Nitrobenzoates; D011868:Radioisotopes; D013431:Sulfates; C085057:4-nitro-2-(3-phenylpropylamino)benzoate; D019343:Citric Acid; D002713:Chlorine; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; C030691:gluconic acid