Terbutaline stimulates alveolar fluid resorption in hyperoxic lung injury

Lasnier, Joseph M., O. Douglas Wangensteen, Laura S. Schmitz, Cynthia R. Gross, and David H. Ingbar. Terbutalinestimulates alveolar fluid resorption in hyperoxic lung injury.J. Appl. Physiol. 81(4):1723-1729, 1996.Alveolar fluid resorption occurs by active epithelial sodium transport and is accelerated by terbutaline inhealthy lungs. We investigated the effect of terbutaline on the rate ofalveolar fluid resorption from rat lungs injured by hyperoxia. Ratsexposed to >95% O₂ for 60 h,sufficient to increase wet-to-dry lung weight and cause alveolar edema,were compared with air-breathing control rats. After anesthesia, theanimals breathed 100% O₂ for 10 min through a tracheostomy. Ringer solution was instilled into thealveoli, and the steady-state rate of volume resorbed at 6 cmH₂O pressure was measured via apipette attached to the tracheostomy tubing. Ringer solution in someanimals contained terbutaline(10³ M), ouabain(10³ M), or both. Normoxicanimals resorbed 49 ± 6 µl ^· kg^{1 ·} min¹;ouabain reduced this by 39%, whereas terbutaline increased the rate by75%. The effect of terbutaline was blocked by ouabain. Hyperoxicanimals absorbed 78 ± 9 µl ^· kg^{1 ·} min¹;ouabain reduced this by 44%. Terbutaline increased the rate by a meanof 39 µl ^· kg^{1 ·} min¹,similar to the absolute effect seen in the normoxic group, and this wasblocked by ouabain. Terbutaline accelerates fluid resorption from bothnormal and injured rat lungs via its effects on active sodiumtransport.