Isoproterenol improves ability of lung to clear edema in rats exposed to hyperoxia.
Exposure of adult rats to 100% O(2) results in lung injury and decreases active sodium transport and lung edema clearance. It has been reported that beta-adrenergic agonists increase lung edema clearance in normal rat lungs by upregulating alveolar epithelial Na(+)-K(+)-ATPase function. This study was designed to examine whether isoproterenol (Iso) affects lung edema clearance in rats exposed to 100% O(2) for 64 h. Active Na(+) transport and lung edema clearance decreased by approximately 44% in rats exposed to acute hyperoxia. Iso (10(-6) M) increased the ability of the lung to clear edema in room-air-breathing rats (from 0.50 +/- 0.02 to 0.99 +/- 0. 05 ml/h) and in rats exposed to 100% O(2) (from 0.28 +/- 0.03 to 0. 86 +/- 0.09 ml/h; P < 0.001). Disruption of intracellular microtubular transport of ion-transporting proteins by colchicine (0. 25 mg/100 g body wt) inhibited the stimulatory effects of Iso in hyperoxia-injured rat lungs, whereas the isomer beta-lumicolchicine, which does not affect microtubular transport, did not inhibit active Na(+) transport stimulated by Iso. Accordingly, Iso restored the lung's ability to clear edema after hyperoxic lung injury, probably by stimulation of the recruitment of ion-transporting proteins (Na(+)-K(+)-ATPase) from intracellular pools to the plasma membrane in rat alveolar epithelium.
Saldías
F J
FJ
Division of Pulmonary and Critical Care Medicine, Michael Reese Hospital, University of Illinois at Chicago, Chicago, Illinois 60616, USA. Esair@aol.com
Comellas
A
A
Ridge
K M
KM
Lecuona
E
E
Sznajder
J I
JI
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D018496:Hyperoxia / Q000150:complications* / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D055370:Lung Injury; D008297:Male; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism; D011654:Pulmonary Edema / Q000188:drug therapy* / Q000209:etiology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D000318:Adrenergic beta-Agonists; D002352:Carrier Proteins; D000254:Sodium-Potassium-Exchanging ATPase; D007545:Isoproterenol