Alveolar sodium and liquid transport in mice.
We have developed a simple isolated lung preparation for measurement of liquid and solute fluxes across mouse alveolar epithelium. Liquid instilled into air spaces was absorbed at the rate (J(w)) of 3.7 +/- 0.32 ml x h(-1) x g dry lung wt(-1) x J(w) was significantly depressed by ouabain (P < 0.001) and amiloride (P < 0.001). Omission of glucose from the instillate or addition of the Na(+)-glucose cotransport inhibitor phloridzin did not affect J(w). However, the low epithelial lining fluid glucose concentration (one-third that of plasma), the larger-than-mannitol permeability of methyl-alpha-D-glucopyranoside, and the presence of Na(+)-glucose cotransporter SGLT1 mRNA in mouse lung tissue suggest that there is a Na(+)-glucose cotransporter in the mouse alveolar-airway barrier. Isoproterenol stimulated J(w) (6.5 +/- 0.45 ml x h(-1) x g dry lung wt(-1); P < 0.001), and this effect was blocked by amiloride, benzamil, ouabain, and the specific beta(2)-adrenergic antagonist ICI-118551 but not by atenolol. Similar stimulation was obtained with terbutaline (6.4 +/- 0.46 ml x h(-1) x g dry lung wt(-1)). Na(+) unidirectional fluxes out of air spaces varied in agreement with J(w) changes. Thus alveolar liquid absorption in mice follows Na(+) transport via the amiloride-sensitive pathway, with little contribution from Na(+)-glucose cotransport, and is stimulated by beta(2)-adrenergic agonists.
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Service de Chirurgie Thoracique et Cardiovasculaire, Centre Hospitalier Universitaire de Caen, 14000 Caen, France.
Saumon
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D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D004232:Diuretics / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D009924:Organ Culture Techniques; D010042:Ouabain / Q000494:pharmacology; D010695:Phlorhizin / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000378:metabolism*; D011654:Pulmonary Edema / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D012964:Sodium / Q000378:metabolism*; D051269:Sodium-Glucose Transporter 1; D013726:Terbutaline / Q000494:pharmacology; D014867:Water / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D004232:Diuretics; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D011412:Propanolamines; D012333:RNA, Messenger; C495675:Slc5a1 protein, mouse; D051269:Sodium-Glucose Transporter 1; C013407:benzamil; D014867:Water; C026777:ICI 118551; D010042:Ouabain; D000584:Amiloride; D012964:Sodium; D010695:Phlorhizin; D005947:Glucose; D007545:Isoproterenol; D013726:Terbutaline