title: Effect of epinephrine on alveolar liquid clearance in the rat.
abstract: Endogenous epinephrine has been found to increase alveolar liquid clearance (ALC) in several pulmonary edema models. In this study, we infused epinephrine intravenously for 1 h in anesthetized rats to produce plasma epinephrine concentrations commonly observed in this species under stressful conditions and measured ALC by mass balance. Epinephrine increased ALC from 31.5 +/- 3.2 to 48.9 +/- 1.1 (SE)% of the instilled volume (P < 0.05). The increased ALC was prevented by either propranolol or amiloride. To determine whether ALC returns to normal after plasma epinephrine concentration normalizes, we measured ALC 2 h after stopping an initial 1-h epinephrine infusion and found ALC to be at baseline values. Finally, to determine whether desensitization of the liquid clearance response occurs, we evaluated the effects of both repeated 1-h infusions and a continuous 4-h infusion of epinephrine on ALC and found no reduction in ALC under either condition. We conclude that epinephrine increases ALC by stimulating beta-adrenoceptors and sodium transport, that the increase is reversible once plasma epinephrine concentration normalizes, and that desensitization of the ALC response does not appear to occur after 4 h of continuous epinephrine exposure.
authors.affiliation: Department of Physiology, Northeastern Ohio Universities College of Medicine, Rootstown, Ohio 44272, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Charron
authors.forename: J P
authors.initials: JP
authors.lastname: Fawley
authors.forename: M B
authors.initials: MB
authors.lastname: Maron
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D011433:Propranolol / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D012709:Serum Albumin / Q000378:metabolism; D013997:Time Factors
chemical_list: D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D012709:Serum Albumin; D000584:Amiloride; D011433:Propranolol; D009638:Norepinephrine; D004837:Epinephrine