Alveolar liquid clearance in the anesthetized ventilated guinea pig.
Alveolar liquid clearance was examined in ventilated, anesthetized guinea pigs. An isosmolar 5% albumin solution was instilled into the lungs. Alveolar liquid clearance was studied over 1 h and was measured from the increase in alveolar protein concentration as water was reabsorbed. Basal alveolar liquid clearance was 38% of instilled volume. The high basal alveolar liquid clearance was not secondary to endogenous catecholamine release. Compared with control animals, epinephrine and the general beta-adrenergic agonist isoproterenol increased alveolar liquid clearance to approximately 50% of instilled volume (P < 0.05), whereas the beta 2-adrenergic agonist terbutaline was without effect. The stimulation of alveolar liquid clearance by epinephrine or isoproterenol was completely inhibited by the addition of the general beta-adrenergic inhibitor propranolol or the beta 1-adrenergic inhibitor atenolol. Alveolar liquid clearance was inhibited by the sodium-channel inhibitor amiloride by 30-40% in control animals and in animals treated with epinephrine or isoproterenol. Isoproterenol and epinephrine, but not terbutaline, increased adenosine 3',5'-cyclic monophosphate in in vitro incubated lung tissue. The results suggest that alveolar liquid clearance in guinea pigs is mediated partly through amiloride-sensitive sodium channels and that alveolar liquid clearance can be increased by stimulation of primarily beta 1-adrenergic receptors.
Norlin
A
A
Department of Animal Physiology, Lund University, Sweden.
Finley
N
N
Abedinpour
P
P
Folkesson
H G
HG
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001826:Body Fluids / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004232:Diuretics / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D006168:Guinea Pigs; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D012119:Respiration; D013726:Terbutaline / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D004232:Diuretics; D011943:Receptors, Adrenergic, beta; D001262:Atenolol; D000584:Amiloride; D000242:Cyclic AMP; D007545:Isoproterenol; D013726:Terbutaline; D004837:Epinephrine