Tsutomu Sakuma1,*, Mieko Hida2, Yoshihiro Nambu2,
Kazuhiro Osanai2, Hirohisa Toga2, Keiji Takahashi2,
Nobuo Ohya2, Masao Inoue3 and Yoh Watanabe1
1Department of Thoracic Surgery, 2Department of
Pulmonary Medicine, and 3Radioisotope Center, Division of Core
Facility, Medical Research Institute, Kanazawa Medical University, Uchinada,
Ishikawa 920-0293, Japan
*Corresponding author. FAX: +81-76-286-1207
E-mail: sakuma-t@kanazawa-med.ac.jp
Abstract: Because it was still uncertain whether a stimulation of
b1-adrenoceptors accelerated alveolar
fluid clearance in hyperoxic lung injury, the effect of denopamine, a selective
b1-adrenergic agonist, on alveolar
fluid clearance was determined in rats exposed to 93% oxygen for 48 and
56 h. Alveolar fluid clearance was measured by the progressive increase
in the concentration of Evans blue labeled albumin instilled into the alveolar
spaces over 1 h at 37｡C in isolated rat lungs. The principle results were
as follows: 1) Although lung water volume increased in rats exposed to hyperoxia
for 48 and 56 h, basal alveolar fluid clearance did not change for up to
56 h; 2) Denopamine increased alveolar fluid clearance in rats exposed to
hyperoxia as well as in rats without exposure to hyperoxia; 3) Denopamine
primarily increased amiloride-insensitive alveolar fluid clearance in rats
exposed to hyperoxia; 4) The potency of denopmaine was similar to that of
terbutaline, a selective b2-adrenergic
agonist. In summary, denopamine is a potent stimulator of alveolar fluid
clearance in rats exposed to hyperoxia.
Keywords: Pulmonary edema, Lung injury, Sodium transport, Alveolar epithelium
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