β-Agonist activation of an amiloride-insensitive transport mechanism in rabbit pleura
1995; Elsevier BV; Volume: 100; Issue: 1 Linguagem: Inglês
10.1016/0034-5687(94)00120-o
ISSN1872-7611
AutoresLuciano Zocchi, Emilio Agostoni, D. Cremaschi,
Tópico(s)Renal function and acid-base balance
ResumoThe β-agonist terbutaline increases the net rate of liquid absorption from hydrothoraces with albumin-Ringer solution: since β-agonists decrease lymphatic drainage, the effect of terbutaline seems due to an increase in solute-coupled liquid absorption, (Zocchi et al. 1994 Respir. Physiol. 97: 347–356). In this research we determined in anesthetized rabbits the rate of volume change in albumin-Ringer hydrothoraces of different size with amiloride plus terbutaline, and compared it with that previously obtained in hydrothoraces with amiloride alone. The net rate of liquid absorption was 0.09 ml/h greater (P < 0.01) with amiloride plus terbutaline than with amiloride alone. This indicates that terbutaline activates an amiloride-insensitive mechanism of Na+ transport. The increase in net rate of liquid absorption produced by terbutaline persisted with bumetanide 10−6 M and SITS 10−4 M, disappeared almost completely with bumetanide 10−5 M, and completely with furosemide 10−3 M. These findings suggest that the mechanism activated by terbutaline, when the amiloride-sensitive mechanisms of the pleura have been blocked, is a Na+K+2 Cl− or Na+Cl− symport little sensitive to bumetanide.
Referência(s)